xvEPA
United States Atmospheric Research and
Environmental' Protection Exposure Assessment Laboratory
Agency Research Triangle Park NC 27711
EPA/600/4-89/01 7
June 1988
Research and Development
Compendium of
Methods for the
Determination of Toxic
Organic Compounds in
Ambient Air
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EPA/600/4-89/017
June 1988
Compendium of Methods for the
Determination of Toxic Organic
Compounds in Ambient Air
by
William T. Winberry, Jr. and Norma T. Murphy
Engineering-Science
One Harrison Park, Suite 200
401 Harrison Oaks Boulevard
Gary, NC 27513
and
R. M. Riggan
Battelle-Columbus Laboratories
505 King Avenue
Columbus, OH 43201
Revisions
Original Compendium EPA/600/4-84/041 April 1984
First Supplement EPA/600/4-87/006 September 1986
Se ondSup^ment EPA/600/4-89/018 June 1988
Atmospheric Research and Exposure Assessment Laboratory
Office of Research and Development
U S. Environmental Protection Agency
Research Triangle Park, NC 2771 1
Begion 5 , Lilrrar:
230 S. Dearborn-
Chicago, IL &C
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Disclaimer
7h^±±±? ^l?^^ h« be?" ^** Wholly or in
ii
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CONTENTS
/ Page
INTRODUCTION v
TABLE 1. Brief Method Description and Applicability vi
TABLE 2. Method Applicability to Compounds of Primary Interest .... viii
METHODS:
T01 Determination of Volatile Organic Compounds in Ambient Air
Using Tenax® Adsorption and Gas Chromatograph (GC/HS) T01-1
T02 Determination of Volatile Organic Compounds in Ambient Air
by Carbon Molecular Sieve Adsorption and Gas Chromatography/
Mass Spectrometry (GC/MS) T02-1
T03 Determination of Volatile Organic Compounds in Ambient Air
Using Cryogenic Preconcentration Techniques and Gas Chromatog-
raphy with Flame lonization and Electron Capture Detection .... T03-1
T04 Determination of Organochlorine Pesticides and
Polychlorinated Biphenyls in Ambient Air T04-1
T05 Determination of Aldehydes and Ketones in Ambient
Air Using High Performance Liquid Chromatography (HPLC). T05-1
APPENDIX A - EPA Method 608
T06 Determination of Phosgene in Ambient Air Using
High Performance Liquid Chromatography (HPLC) T06-1
T07 Determination of N-Nitrosodimethylamine in Ambient
Air Using Gas Chromatography T07-1
T08 Determination of Phenol and Methyl phenols (Cresols)
in Ambient Air Using High Performance Liquid
Chromatography (HPLC) T08-1
T09 Determination of Polychlorinated Dibenzo-p-Dioxins
(PCDDs) in Ambient Air Using High-Resolution Gas
Chromatography/High-Resolution Mass Spectrometry T09-1
T010 Determination of Organochlorine Pesticides in Ambient
Air Using Low Volume Polyurethane Foam (PUF) Sampling
with Gas Chromatography/Electron Capture Detector (GC/ECD) . . . .T010-1
T011 Determination of formaldehyde in Ambient Air Using
Adsorbent Cartridge Followed By High Performance
Liquid Chromatography (HPLC) . . .T011-1
T012 Determination of Non-methane Organic Compounds (NMOC)
in Ambient Air Using Cryogenic Preconcentration
and Direct Flame lonization Detection (PDFID). T012-1
T013 Determination of Polynuclear Aromatic Hydrocarbons
(PAHs) in Ambient Air Using High Volume Sampling
with Gas Chromatography/Mass Spectrometry (GC/MS)
and High Resolution Liquid Chromatography Analysis T013-1
T014 Determination of Volatile Organic Compounds (VOCs) in
Ambient Air Using SUMMA® Polished Canister Sampling
and Gas Chromatographic (GC) Analysis T014-1
iii
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FOREWORD
Measurement and monitoring research efforts are designed to anticipate
potential environmental problems, to support regulatory actions by developing
an in-depth understanding of the nature and processes that impact health and
the ecology, to provide innovative means of monitoring compliance with regu-
lations, and to evaluate the effectiveness of health and environmental pro-
tection efforts through the monitoring of long-term trends. The Environmental
Monitoring Systems Laboratory, Research Triangle Park, North Carolina, has
responsibility for: assessment of environmental monitoring technology and
systems; implementation of Agency-wide quality assurance programs for air
pollution measurement systems; and supplying technical support to other groups
in the Agency, including the Office of Air and Radiation, the Office of Toxic
Substances, and the Office of Enforcement.
Determination of toxic organic compounds in ambient air is a complex task,
primarily because of the wide variety of compounds of interest and the lack of
standardized sampling and analysis procedures. This methods Compendium has
been prepared to provide a standardized format for such analytical procedures.
A core set of five methods is presented in the original document. In an effort
to update the original Compendium, four specific methods have been developed
and published in a supplemental document. In addition to the Compendium and
Supplement, five new methods have been prepared for inclusion. With this
addition, the Compendium now contains fourteen standardized sampling and anal-
ysis procedures. As advancements are made, the current methods may be modified
from time to time along with new additions to the Compendium.
Gary J. Foley
Director
Environmental Monitoring Systems Laboratory
Research Triangle Park, North Carolina, 27711
iv
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UB XSo osa jaded
INTRODUCTION
This Compendium has been prepared to P^^^^eVestfd^par^es, w,u,
environmental regulatory agencies, « weu . organic compounds in
specific guidance on the **ER? «« '/l.'ulS^e-nt (T'AD) was —'•"
XM.M. ^^^^
"zed format, for selected toxic organic compounds.
Tne current Compendium consists
ered to be of ^ primary l-POrt"«« '» ^Tompend iu™ fS time to time, as such
Additional methods will be Pj»«» '" "e ™K" were selected to cover as many
methods become available. The original methods were se selected). The
analte «™
we
methods become available. The origina metos we selected). The
compounds as possible (i.e., ™J"Ple analyte «™ „ oups of
' be determined by tbe
more general methods.
Each of the methods writeups is self *»Jt.1».M l-Juding pertinent liter-
ature citations) and can be used .1"deefetllhd.entAm°rfictat'ne society for Besting and
may be required in the
future.
„„„ ...
SSSasH
of the specific task.
ealuate the applicability of the method before use.
(1) Riggin, R. M., "Technical Assistance Document
°f •OXnmentaiaprStectT5r Agency", Xswroh TH angle" Park, North Carolina,
1983.
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PUB
JSdBd P8|OAO9J
TABLE 1. BRIEF METHOD DESCRIPTION AND APPLICABILITY
Method
Number
Description
Types of
Compounds Determined
TO-1
TO-2
TO-3
TO-4
TO-5
TO-6
TO-7
TO-8
TO-9
Tenax GC Adsorption
and GC/MS Analysis
Carbon Molecular Sieve
Adsorption and GC/MS
Analysis
Cryogenic Trapping
and GC/FID or ECD
Analysis
High Volume PUF
Sampling and GC/ECD
Analysis
Dinitrophenylhydrazine
Liquid Impinger Sampling
and HPLC/UV Analysis
High Performance Liquid
Chromatography (HPLC)
Thermosorb/N Adsorption
Sodium Hydroxide Liquid
Impinger with High Per-
formance Liquid Chromato-
graphy
High Volume Polyurethane
Foam Sampling with
High Resolution Gas
Chromatography/High
Resolution Mass Spec-
trometry (HRGC/HRMS)
Volatile, nonpolar organics
(e.g., aromatic hydrocarbons,
chlorinated hydrocarbons)
having boiling points in the
range of 80° to 200°C.
Highly volatile, nonpolar
organics (e.g., vinyl chloride,
vinylidene chloride, benzene,
toluene) having boiling points
in the range of -15° to +120°C.
Volatile, nonpolar organics
having boiling points in the
range of -10° to +200°C.
Organochlorine pesticides and
PCBs
Aldehydes and Ketones
Phosgene
N-Nitrosodimethylami ne
Cresol/Phenol
Dioxin
vi
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pu» .
TABLE 1. BRIEF METHOD DESCRIPTION AND APPLICABILITY (Continued)
Method
Number
Description
Types of
Compounds Determined
TO-10
TO-11
TO-12
TO-13
TO-14
Low Volume Polyurethane
Foam (PUF) Sampling With
Gas Chromatography/Electron
Capture Detector (GC/ECD)
Adsorbent Cartridge Followed
By High Performance Liquid
Chromatography (HPLC)
Detection
Cryogenic Preconcentration
and Direct Flame lonization
Detection (PDFID)
PUF/XAD-2 Adsorption
with Gas Chromatography
(GC) and High Performance
Liquid Chromatography
(HPLC) Detection
SUMMA® Passivated Canister
Sampling with Gas Chromatog-
raphy
Pesticides
Formaldehyde
Non-Methane Organic
Compounds (NMOC)
Polynuclear Aromatic
Hydrocarbons (PAHs)
Semi-Volatile and
Volatile Organic
Compounds (SVOC/VOCs)
vii
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1II3UIUIUIAU3 pUB .43O5O.W
TABLE 2. METHOD APPLICABILITY TO COMPOUNDS OF PRIMARY INTEREST
Compound
Applicable
Method(s)
Comments
Acenaphthene
Acenaphthylene
Acetaldehyde
Acetone
Acrolein
Acrylonitrile
Aldrin
Allyl Chloride
Aroclor 1242, 1254
and 1260
Benzaldehyde
Benzene
Benzyl Chloride
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fl uoranthene
Butyraldehyde
Captan
Carbon Tetrachloride
Chlordane
Chlorobenzene
Chloroform
Chloroprene
(2-Chloro-l,3-buta-
diene)
Chlorothalonil
Chlorpyrifos
Chrysene
Cresol
Crotonaldehyde
4,4'-DDE
4,4'-DDT
1,2-Dibromomethane
1,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
1,1-Dichloroethane
1»2-Dichloroethylene
TO-14
TO-14
TO-5, TO-11
TO-11
TO-5, TO-11
TO-2, TO-3
TO-10
TO-2, TO-3
TO-10
TO-5
TO-1, TO-2, TO-3,
TO-14
TO-1, TO-3, TO-14
TO-13
TO-13
TO-13
TO-13
TO-13
TO-13
TO-11
TO-10
TO-1, TO-2, TO-3
TO-14
TO-10
TO-1, TO-3, TO-14
TO-1, TO-2. TO-3
TO-14
TO-1, TO-3
TO-10
TO-10
TO-13
TO-8
.TO-11
TO-4
TO-4
TO-14
TO-14
TO-14
TO-1, TO-3, TO-14
TO-14
TO-14
Extension of TO-11
Extension of TO-11
Extension of TO-11
TO-3 yields better recovery
data than TO-2.
TO-3 yields better recovery
data than TO-2.
TO-14 yields better recovery
data.
Extension of TO-11
Breakthrough volume is very
low using TO-1.
Breakthrough volume is very
low using TO-1
The applicability of these
methods for chloroprene has
not been documented.
Extension of TO-11
vili
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TABLE 2. METHOD APPLICABILITY TO COMPOUNDS OF PRIMARY INTEREST (Continued)
Applicable
Method(s)
Compound
Comments
1,2-Dichloropropane
1,3-Dichloropropane
Dichlorovos
Dicofol
Dieldrin
2,5-Dimethylbenzaldehyde
Dioxin
Endrin
Endrin Aldehyde
Ethyl Benzene
Ethyl Chloride
Ethylene Dichloride
(1,2-Dichloroethane)
4-Ethyltoluene
Fluoranthene
Fluorene
Folpet
Formaldehyde
Freon 11
Freon 12
Freon 113
Freon 114
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
and a-Hexachloro-
cyclohexane
Hexachlorobutadiene
Hexachlorocyclopenta-
diene
Hexanaldehyde
Indeno(l,2,3-cd)pyrene
Isovaleraldehyde
Lindane (a-BHC)
Methoxychlor
Methyl Benzene
Methyl Chloride
Methyl Chloroform
(1,1,1-Trichloroethane)
Methylene chloride
Mexacarbate
Mirex '
Naphthalene
Nitrobenzene
N-Nitrosodimethylamine
trans-Nonachlor
TO-14
TO-14
TO-10
TO-10
TO-10
TO-11
TO-9
TO-10
TO-10
TO-14
TO-14
TO-1, TO-2, TO-3
TO-14
TO-14
TO-13
TO-13
TO-10
TO-5, TO-11
TO-14
TO-14
TO-14
TO-14
TO-10
TO-10
TO-10
TO-10
TO-14
TO-10
TO-11
TO-13
TO-11
TO-10
TO-10
TO-14
TO-14
TO-1, TO-2, TO-3
TO-14
TO-2, TO-3, TO-14
TO-10
TO-10
TO-13
TO-1, TO-3
TO-7
TO-10
Extension of TO-11
Breakthrough volume very low
using TO-1.
Extension of TO-11
Extension of TO-11
Breakthrough volume very low
using TO-1.
1x
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TABLE 2. METHOD APPLICABILITY TO COMPOUNDS OF PRIMARY INTEREST (Continued)
Compound
Non-methane Organic
Compounds
Oxychlordane
Pentachlorobenzene
Pentachlorphenol
p.p1- DDE
P,p'- DDT
Perchloroethylene
(tetrachloroethylene)
Phenanthrene
Phenol
Phosgene
Polychlorlnated bi-
phenyls (PCBs)
Propanal
Propionaldehyde
Pyrene
Ronnel
1,2,3,4-Tetrachloro-
benzene
1,1,2,2-Tetrachloro-
ethane
o-Tolualdehyde
m-Tolualdehyde
p-Tolualdehyde
Toluene
1 »2,3-Trichlorobenzene
1,2,4-Trichlorobenzene
1,1,2-Trichloroethane
Trichloroethylene
2,4,5-Trichlorophenol
1,2,4-Trimethylbenzene
1,3,5-Trimethylbenzene
Valeraldehyde
Vinyl Benzene
Vinyl Chloride
Vinyl Trichloride
Vinylidine Chloride
(1,1-dichloroethene)
o.m.p-Xylene
Applicable
Method(s)
Comments
TO-12
TO-10
TO-10
TO-10
TO-10
TO-10
TO-1, (TO-2?), TO-3,
TO-13
TO-8
TO-6
TO-4, TO-9
TO-5
TO-11
TO-13
TO-10
TO-10
TO-14
TO-11
TO-11
TO-11
TO-1, TO-2, TO-3,
TO-14
TO-10, TO-14
TO-14
TO-14
TO-1, TO-2, TO-3,
TO-14
TO-10
TO-14
TO-14
TO-11
TO-14
TO-2, TO-3, TO-14
TO-14
TO-2, TO-3, TO-14
TO-1, TO-3, TO-14
TO-2 performance has not been
documented for this compound.
Extension of TO-11
Using PUF in combination with
Tenax* GC solid adsorbent.
Extension of TO-11
Extension of TO-11
Extension of TO-11
Using PUF in combination with
Tenax* GC solid adsorbent.
Extension of TO-11
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TOl Revision 1.0
T01 April, 1984
1. Scope
, , The document describes a generalized protocol for Election
and determination of certain volatile organic compounds
which can be captured on Tenax* GC (poly(2,6-0lphenyi
-;:::;;;::> srrrs r--
, t r;::^;: -iir anil-!—- r
to acco-odate procedures currently in use. Hoover, such
within each laboratory
1.3
Organ1cs having boiling points 1. tne range of WP""-^
80» - 200-C. However, not all compounds falling int. th,s
category can be determined. Table 1 gives a listing of
Ids for .Men the method has been used. "^ compo.d
may yield satisfactory results but validate by the ,nd,»,du.l
user is required.
2. Applicable Documents
2.1 ASTM Standards:
D1356 Definitions of Terms Related to Atmospheric Sampling
and Analysis.
E355 Recommended Practice for Gas Chromatography Terms and
Relationships.
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T01-2
2.3 Other documents:
Existing procedures (1-3).
U.S. EPA Technical Assistance Document (4).
3. Summary of Protocol
3.1 Ambient air is drawn through a cartridge containing M-2
grams of Tenax and certain volatile organic compounds are
trapped on the resin while highly volatile organic compounds
and most inorganic atmospheric constituents pass through the
cartridge. The cartridge is then transferred to the
laboratory and analyzed.
3.2 For analysis the cartridge is placed in a heated chamber and
purged with an inert gas. The inert gas transfers the
volatile organic compounds from the cartridge onto a cold trap
and subsequently onto the front of the GC column which is held
at low temperature (e.g. - 70'C). The GC column temperature is
then increased (temperature programmed) and the components
eluting from the column are identified and quantified by mass
spectrometry. Component identification is normally accomplished,
using a library search routine, on the basis of the GC retention
time and mass spectral characteristics. Less sophistacated
detectors (e.g. electron capture or flame ionization) may be
used for certain applications but their suitability for a given
application must be verified by the user.
3.3 Due to the complexity of ambient air samples only high resolution
(i.e. capillary) GC techniques are considered to be acceptable
in this protocol.
4. Significance
4.1 Volatile organic compounds are emitted into the atmosphere from
a variety of sources including industrial and commercial
facilities, hazardous waste storage facilities, etc. Many of
these compounds are toxic; hence knowledge of the levels of
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TO!-3
such materials in the ambient atmosphere is required in order
to determine human health impacts.
4.2 Conventional air monitoring methods (e.g. for workspace
monitoring) have relied on carbon adsorption approaches with
subsequent solvent desorption. Such techniques allow
subsequent injection of only a small portion, typically 1-5%
of the sample onto the GC system. However, typical
ambient air concentrations of these compounds require a more
sensitive approach. The thermal desorption process, wherein
the entire sample is introduced into the analytical (GC/MS) ,
system fulfills this need for enhanced sensitivity.
5. Definitions
Definitions used in this document and any user prepared SOPs should
be consistent with ASTM 01356(6). All abbreviations and symbols
are defined with this document at the point of use.
6. INTERFERENCES
6.1 Only compounds having a similar mass spectrum and GC retention
time compared to the compound of interest will interfere in
the method. The most commonly encountered interferences are
structural isomers.
6.2 Contamination of the Tenax cartridge with the compound(s)
of interest is a commonly encountered problem in the method.
The user must be extremely careful in the preparation, storage,
and handling of the cartridges throughout the entire sampling
and analysis process to minimize this problem.
7. Apparatus
7 i Gas Chromatograph/Mass Spectrometry system - should be capable
of subambient temperature programming. Unit mass resolution
or better up to 800 amu. Capable of scanning 30-440 amu region
every 0.5-1 second. Equipped with data system for instrument
control as well as data acquisition, processing and storage.
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TO!-4
7.2 Thermal Desorption Unit - Designed to accommodate Tenax
cartridges in use. See Figure 2a or b.
7.3 Sampling System - Capable of accurately and precisely
drawing an air flow of 10-500 ml/minute through the Tenax
cartridge. (See Figure 3a or b.)
7.4 Vacuum oven - connected to water aspirator vacuum supply.
7.5 Stopwatch
7.6 Pyrex disks - for drying Tenax.
7.7 Glass jar - Capped with Teflon-lined screw cap. For
storage of purified Tenax.
7.8 Powder funnel - for delivery of Tenax into cartridges.
7.9 Culture tubes - to hold individual glass Tenax cartridges.
7.10 Friction top can (paint can) - to hold clean Tenax cartridges.
7.11 Filter holder - stainless steel or aluminum (to accommodate
1 inch diameter filter). Other sizes may be used if desired.
(optional)
7.12 Thermometer - to record ambient temperature.
7.13 Barometer (optional).
7.14 Dilution bottle - Two-liter with septum cap for standards
preparation.
7.15 Teflon stirbar - 1 inch long.
7.16 Gas-tight glass syringes with stainless steel needles -
10-500 M! for standard injection onto GC/MS system..
7.17 Liquid microliter syringes - 5,50 uL for injecting neat
liquid standards into dilution bottle.
7.18 Oven - 60 + 5°C for equilibrating dilution flasks.
7.19 Magnetic stirrer.
7.20 Heating mantel.
7.21 Variac
7.22 Soxhlet extraction apparatus and glass thimbles - for purifying
Tenax.
7.23 Infrared lamp - for drying Tenax.
7.24 GC column - SE-30 or alternative coating, glass capillary or
fused silica.
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T01-5
7.25 Psychrometer - to determine ambient relative humidity.
(optional).
8. Reagents and Materials
8.1 Empty Tenax cartridges - glass or stainless steel (See
Figure la or b).
8.2 Tenax 60/80 mesh (2,6-diphenylphenylene oxide polymer).
8.3 Glasswool - silanized.
8.4 Acetone - Pesticide quality or equivalent.
8.5 Methanol - Pesticide quality, or equivalent.
8.6 Pentane - Pesticide quality or equivalent.
8.7 Helium - Ultra pure, compressed gas. (99.9999%)
8.8 Nitrogen - Ultra pure, compressed gas. (99.9999%)
8.9 Liquid nitrogen.
8 10 Polyester gloves - for handling glass Tenax cartridges.
8.1.1 Glass Fiber Filter - one inch diameter, to fit in filter holder.
(optional)
8.12 Perfluorotributyl amine (FC-43).
s'.13 Chemical Standards - Neat compounds of interest. Highest
purity available.
8.14 Granular activated charcoal - for preventing contamination of
Tenax cartridges during storage.
9. Cartridge Construction and Preparation
9.1 Cartridge Design
9.1.1 Several cartridge designs have been reported in the
literature (1-3). The most common (1) is shown in
Figure la. This design minimizes contact of the
sample with metal surfaces, which can lead to
decomposition in certain cases. However, a
disadvantage of this design is the need to rigorously
avoid contamination of the outside portion of the
cartridge since the entire surface is subjected to the
purge gas stream during the desorption porcess.
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TO!-6
Clean polyester gloves must be worn at all times
when handling such cartridges and exposure of the
open cartridge to ambient air must be minimized.
9.1.2 A second common type of design (3) is shown in
Figure Ib. While this design uses a metal (stainless
steel) construction, it eliminates the need to avoid
direct contact with the exterior surface since only
the interior of the cartridge is purged.
9.1.3 The thermal desorption module and sampling system
must be selected to be compatible with the particular
cartridge design chosen. Typical module designs
are shown in Figures 2a and b. These designs are
suitable for the cartridge designs shown in Figures
la and Ib, respectively.
9.2 Tenax Purification
9.2.1 Prior to use the Tenax resin is subjected to a
series of solvent extraction and thermal treatment
steps. The operation should be conducted in an area
where levels of volatile organic compounds (other than
the extraction solvents used) are minimized.
9.2.2 All glassware used in Tenax purification as well as
cartridge materials should be thoroughly cleaned by
water rinsing followed by an acetone rinse and dried
in an oven at 250°C.
9.2.3 Bulk Tenax is placed in a glass extraction thimble
and held in place with a plug of clean glasswool.
The resin is then placed in the soxhlet extraction
apparatus and extracted sequentially with methanol
and then pentane for 16-24 hours (each solvent) at
approximately 6 cycles/hour. Glasswool for cartidge
preparation should be cleaned in the same manner as
Tenax.
9.2.4 The extracted Tenax is immediately placed in an open
glass dish and heated under an infrared lamp for two
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T01-7
hours in a hood. Care must be exercised to avoid
over heating of the Tenax by the infrared lamp.
The Tenax is then placed in a vacuum oven (evacuated
using a water aspirator) without heating for one hour.
An inert gas (helium or nitrogen) purge of 2-3
ml/minute is used to aid in the removal of solvent
vapors. The oven temperature is then increased to
110°C, maintaining inert gas flow and held for one
hour. The oven temperature control is then shut
off and the oven is allowed to cool to room temperature.
Prior to opening the oven, the oven is slightly
pressurized with nitrogen to prevent contamination
with ambient air. The Tenax is removed from the oven
and sieved through a 40/60 mesh sieve (acetone rinsed
and oven dried) into a clean glass vessel. If the Tenax
is not to be used immediately for cartridge preparation
it should be stored in a clean glass jar having a
Teflon-lined screw cap and placed in a desiccator.
9.3 Cartridge Preparation and Pretreatment
9.3.1 All cartridge materials are pre-cleaned as described
in Section 9.2.2. If the glass cartridge des< ]n shown
in Figure la is employed all handling should bd
conducted wearing polyester gloves.
9.3.2 The cartridge is packed by placing a 0.5-lcm glass-
wool plug in the base of the cartridge and then
filling the cartridge to within approximately 1 cm
of the top. A 0.5-lcm glasswool plug is placed in
the top of the cartridge.
9.3.3 The cartridges are then thermally conditioned by
heating for four hours at 270°C under an inert gas
(helium) purge (100 - 200 ml/min).
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T01-8
9.3.4 After the four hour heating period the cartridges
are allowed to cool. Cartridges of the type shown
in Figure la are immediately placed (without cooling)
in clean culture tubes having Teflon-lined screw caps
with a glasswool cushion at both the top and the bottom.
Each tube should be shaken to ensure that the cartridge
is held firmly in place. Cartridges of the type shown
in Figure Ib are allowed to cool to room temperature under
inert gas purge and are then closed with stainless steel
plugs.
9.3.5 The cartridges are labeled and placed in a tightly
sealed metal can (e.g. paint can or similar friction
top container). For cartridges of the type shown
in Figure la the culture tube, not the cartridge,is
labeled.
9.3.6 Cartridges should be used for sampling within 2 weeks
after preparation and analyzed within two weeks after
sampling. If possible the cartridges should be stored
at -20°C in a clean freezer (i.e. no solvent extracts
or other sources of volatile organics contained in the
freezer).
10. Sampling
10.1 Flow rate and Total Volume Selection
10.1.1 Each compound has a characteristic retention volume
(liters of air per gram of adsorbent) which must not
be exceeded. Since the retention volume is a function
of temperature, and possibly other sampling variables,
one must include an adequate margin of safety to
ensure good collection efficiency. Some considerations
and guidance in this regard are provided in a recent
report (5). Approximate breakthrough volumes at 38°C
(100°F) in liters/gram of Tenax are provided in Table 1.
These retention volume data are supplied only as rough
guidance and are subject to considerable variability,
depending on cartridge design as well as sampling
parameters and atmospheric conditions.
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T01-9
10.1.2 To calculate the maximum total volume of air which
can be sampled use the following equation:
VMAX
where
VMAX 1s the calculated maximum total volume in liters.
Vb is the breakthrough volume for the least retained
compound of interest (Table 1) in liters per gram
of Tenax.
W is the weight of Tenax in the cartridge, in grams.
1.5 is a dimensionless safety factor to allow for
variability in atmospheric conditions. This factor
is appropriate for temperatures in the range of
25-30°C. If higher temperatures are encountered the
factor should be increased (i.e. maximum total volume
decreased).
10.1.3 To calculate maximum flow rate use the following
equation:
- MX x 1000
XHHA t
where
QMAX 1s the calculated maximum flow rate in milli-
leters per minute.
t is the desired sampling time in minutes. Times
greater than 24 hours (1440 minutes) generally
are unsuitable because the flow rate required
is too low to be accurately maintained.
10.1.4 The maximum flow rate QMAX should yield a linear flow
velocity of 50-500 cm/minute. Calculate the linear
velocity corresponding to the maximum flow rate
using the following equation:
irr
-------
T01-10
where
B is the calculated linear flow velocity in
centimeters per minute.
r is the internal radius of the cartridge in
centimeters.
If B is greater than 500 centimeters per minute
either the total sample volume (VMAX) should be
reduced or the sample flow rate (QMAX) should be
reduced by increasing the collection time. If B is
less than 50 centimeters per minute the sampling rate
(QMAX) should be increased by reducing the sampling
time. The total sample value (VMAX) cannot be
increased due to component breakthrough.
10.1.4 The flow rate calculated as described above defines
the maximum flow rate allowed. In general, one should
collect additional samples in parallel, for the same
time period but at lower flow rates. This practice
yields a measure of quality control and is further
discussed in the literature (5). In general, flow
rates 2 to 4 fold lower than the maximum flow rate
should be employed for the parallel samples. In
all cases a constant flow rate should be achieved
for each cartridge since accurate integration of the
analyte concentration requires that the flow be
constant over the sampling period.
10.2 Sample Collection
10.2.1 Collection of an accurately known volume of air
is critical to the accuracy of the results. For
this reason the use of mass flow controllers,
rather than conventional needle valves or orifices
is highly recommended, especially at low flow
velocities (e.g. less than 100 mi 11 niters/minute).
Figure 3a illustrates a sampling system utilizing
mass flow controllers. This system readily allows
for collection of parallel samples. Figures 3b
shows a commercially available system based on
needle valve flow controllers.
-------
TOl.-ll
10 2 2 Prior to sample collection insure that the sampling
flow rate has been calibrated over a range including
the rate to be used for sampling, with a "dummy"
Tenax cartridge in place. Generally calibration
is accomplished using a soap bubble flow meter
or calibrated wet test meter. The flow calibration
device is connected to the flow exit, assuming
the entire flow system is sealed. ASTM Method
D3686 describes an appropriate calibration scheme,
not requiring a sealed flow system downstream
of the pump.
10 2 3 The flow rate should be checked before and after
each sample collection. If the sampling interval
exceeds four hours the flow rate should be checked
at an intermediate point during sampling as well.
In general, a rotameter should be included, as .
showed in Figure 3b, to allow observation of the
sampling flow rate without disrupting the sampling
process.
10 2 4 To collect an air sample the cartridges are removed
from the sealed container just prior to Initiation
of the collection process. If glass cartridges
(Figure la) are employed they must be handled
only with polyester gloves and should not contact
any other surfaces.
10.2.5 A particulate filter and holder are placed on
the inlet to the cartridges and the exit end
of the cartridge is connected to the sampling
apparatus. In many sampling situations the use
of a filter is not necessary if only the total
concentration of a component is desired. Glass
cartridges of the type shown in Figure la are
connected using teflon ferrules and Swagelok
(stainless steel or teflon) fittings. Start the
pump and record the following parameters on an
appropriate data sheet (Figure 4): data, sampling
location, time, ambient temperature, barometric
-------
T01-12
pressure, relative humidity, dry gas meter reading
(if applicable) flow rate, rotameter reading (if
applicable), cartridge number and dry gas meter
serial number.
10.2.6 Allow the sampler to operate for the desired time,
periodically recording the variables listed above.
Check flow rate at the midpoint of the sampling
interval if longer than four hours.
At the end of the sampling period record the
parameters listed in 10.2.5 and check the flow
rate and record the value. If the flows at the
beginning and end of the sampling period differ
by more than 10% the cartridge should be marked
as suspect.
10.2.7 Remove the cartridges (one at a time) and place
in the original container (use gloves for glass
cartridges). Seal the cartridges or culture tubes
in the friction-top can containing a layer of
charcoal and package for immediate shipment to
the laboratory for analysis. Store cartridges
at reduced temperature (e.g. - 20°C) before analysis
if possible to maximize storage stability.
10.2.8 Calculate and record the average sample rate for
each cartridge according to the following equation:
A = _
where
QA = Average flow rate in ml/minute.
Ql, Q2, QN = Flow rates determined at
beginning, end, and immediate points
during sampling.
N = Number of points averaged.
10.2.9 Calculate and record the total volumetric flow for
each cartridge using the following equation:
V = T x QA
1000
-------
T01-13
where
Vm = Total volume sampled in liters at measured
temperature and pressure.
T£ = Stop time.
T] = Start time.
T - Sampling time = T£ - T-J , minutes
10.2.10 The total volume (Vs) at standard conditions,
25°C and 760 mmHg, is calculated from the
following equation:
where
PA 298
Vs = Vm x —750 x 273 + tA
PA = Average barometric pressure, mmHg
t/\ = Average ambient temperature, °C.
11. GC/MS Analysis
11.1 Instrument Set-up
11.1.1 Considerable variation from one laboratory to
another is expected in terms of instrument configuration.
Therefore each laboratory must be responsible
for verifying that their particular system yields
satisfactory results. Section 14 discusses specific
performance criteria which should be met.
11.1.2 A block diagram of the typical GC/MS system
required for analysis of Tenax cartridges is
depicted in Figure 5. The operation of such
devices is described in 11.2.4. The thermal
desorption module must be designed to accommodate
the particular cartridge configuration. Exposure
of the sample to metal surfaces should be
minimized and only stainless steel, or nickel metal
surfaces should be employed.
-------
T01-14
The volume of tubing and fittings leading from
the cartridge to the GC column must be minimized
and all areas must be well-swept by helium carrier
gas.
11.1.3 The GC column inlet should be capable of being
cooled to -70°C and subsequently increased rapidly
to approximately 30°C. This can be most readily
accomplished using a GC equipped with subambient
cooling capability (liquid nitrogen) although
other approaches such as manually cooling the
inlet of the column in liquid nitrogen may be
acceptable.
11.1.4 The specific GC column and temperature program
employed will be dependent on the specific compounds
of interest. Appropriate conditions are described
in the literature (1-3). In general a nonpolar
stationary phase (e.g. SE-30, OV-1) temperature
programmed from 30°C to 200°C at 8°/minute will
be suitable. Fused silica bonded phase columns
are preferable to glass columns since they are
more rugged and can be inserted directly into
the MS ion source, thereby eliminating the need
for a GC/MS transfer line.
11.1.5 Capillary column dimensions of 0.3 mm ID and 50
meters long are generally appropriate although
shorter lengths may be sufficient in many cases.
11.1.6 Prior to instrument calibration or sample analysis
the GC/MS system is assembled as shown in Figure
5. Helium purge flows (through the cartridge)
and carrier flow are set at approximately 10 ml/
minute and 1-2 ml/minute respectively. If applicable,
the injector sweep flow is set at 2-4 ml/minute.
-------
T01-15
11.1.7 Once the column and other system components are
assembled and the various flows established the
column temperature is increased to 250°C for
approximately four hours (or overnight if desired)
to condition the column.
11.1.8 The MS and data system are set according to the
manufacturer's instructions. Electron impact
ionization (70eV) and an electron multiplier gain
of approximately 5 x 10* should be employed.
Once the entire GC/MS system has been setup the
system is calibrated as described in Section 11.2.
The user should prepare a detailed standard
operating procedure (SOP) describing this process
for the particular instrument being used.
11.2 Instrument Calibration
11.2.1 Tuning and mass standarization of the MS system
is performed according to manufacturer's instructions
and relevant information from the user prepared
SOP. Perfluorotributyl amine should generally
be employed for this purpose. The material
is introduced directly into the ion source
through a molecular leak. The instrumental
parameters (e.g. lens voltages, resolution,
etc.) should be adjusted to give the relative
ion abundances shown in Table 2 as well as
acceptable resolution and peak shape. If
these approximate relative abundances cannot
be achieved, the ion source may require cleaning
according to manufacturer's instructions.
In the event that the user's instrument cannot
achieve these relative ion abundances, but
is otherwise operating properly, the user
may adopt another set of relative abundances
as performance criteria.
-------
T01-16
However, these alternate values must be repeatable
on a day-to-day basis.
11.2.2 After the mass standarization and tuning process
has been completed and the appropriate values
entered into the data system the user should
then calibrate the entire system by introducing
known quantities of the standard components
of interest into the system. Three alternate
procedures may be employed for the calibration
process including 1) direct syringe injection
of dilute vapor phase standards, prepared
in a dilution bottle, onto the GC column, 2)
Injection of dilute vapor phase standards
into a carrier gas stream directed through the
Tenax cartridge, and 3) introduction of permeation
or diffusion tube standards onto a Tenax cartridge.
The standards preparation procedures for each
of these approaches are described in Section
13. The following paragraphs describe the
instrument calibration process for each of
these approaches.
11.2.3 If the instrument is to be calibrated by direct
injection of a gaseous standard, a standard
is prepared in a dilution bottle as described
in Section 13.1. The GC column is cooled
to -70°C (or, alternately, a portion of the
column inlet is manually cooled with liquid
nitrogen). The MS and data system is set
up for acquisition as described in the relevant
user SOP. The ionization filament should be turned
off during the initial 2-3 minutes of the run to
allow oxygen and other highly volatile components
to elute. An appropriate volume (less than 1 ml)
of the gaseous standard is injected onto the GC
system using an accurately calibrated gas tight syringe,
-------
TO!-17
The system clock is started and the column is
maintained at -70°C (or liquid nitrogen inlet cooling)
for 2 minutes. The column temperature is rapidly
increased to the desired initial temperature (e.g. 30°C).
The temperature program is started at a consistent
time (e.g. four minutes) after injection. Simultaneously
the ionization filament is turned on and data acquisition
is initiated. After the last component of interest has
eluted acquisiton is terminated and the data is processed
as described in Section 11.2.5. The standard injection
process is repeated using different standard volumes as
desired.
11.2.4 If the system is to be calibrated by analysis of
spiked Tenax cartridges a set of cartridges is
prepared as described in Sections 13.2 or 13.3.
Prior to analysis the cartridges are stored as
described in Section 9.3. If glass cartridges (Figure la)
are employed care must be taken to avoid direct
contact, as described earlier. The GC column is
cooled to -70°C, the collection loop is immersed in
liquid nitrogen and the desorption module is
maintained at 250°C. The inlet valve is placed in the
desorb mode and the standard cartridge is placed in
the desorption module, making certain that no leakage
of purge gas occurs. The cartridge is purged
for 10 minutes and then the inlet valve is placed in
the inject mode and the liquid nitrogen source removed
from the collection trap. The GC column is maintained
at -70°C for two minutes and subsequent steps are as
described in 11.2.3. After the process is complete the
cartridge is removed from the desorption module and
stored for subsequent use as described in Section 9.3.
-------
T01-18
11.2.5 Data processing for instrument calibration involves
determining retention times, and integrated characteristic
ion intensities for each of the compounds of interest.
In addition, for at least one chromatographic run,the
individual mass spectra should be inspected and
compared to reference spectra to ensure proper
instrumental performance. Since the steps involved
in data processing are highly instrument specific, the
user should prepare a SOP describing the process for
individual use. Overall performance criteria for
instrument calibration are provided in Section 14. If
these criteria are not achieved the user should refine
the instrumental parameters and/or operating
procedures to meet these criteria.
11.3 Sample Analysis
11.3.1 The sample analysis process is identical to that
described in Section 11.2.4 for the analysis of standard
Tenax cartridges.
11.3.2 Data processing for sample data generally involves
1) qualitatively determining the presence or absence
of each component of interest on the basis of a set
of characteristic ions and the retention time using
a reverse-search software routine, 2) quantification
of each identified component by integrating the intensity
of a characteristic ion and comparing the value to
that of the calibration standard, and 3) tentative
identification of other components observed using a
forward (library) search software routine. As for
other user specific processes, a SOP should be prepared
describing the specific operations for each individual
laboratory.
-------
T01-19
12. Calculations
12.1 Calibration Response Factors
12.1.1 Data from calibration standards is used to calculate
a response factor for each component of interest.
Ideally the process involves analysis of at least
three calibration levels of each component during a
given day and determination of the response
factor (area/nanogram injected) from the linear
least squares fit of a plot of nanograms injected ,
versus area (for the characteristic ion).
In general quantities of component greater
than 1000 nanograms should not be injected
because of column overloading and/or MS response
nonlinearity.
12.1.2 In practice the daily routine may not always
allow analysis of three such calibration standards.
In this situation calibration data from consecutive
days may be pooled to yield a response factor,
provided that analysis of replicate standards
of the same concentration are shown to agree
within 20% on the consecutive days. One standard
concentration, near the midpoint of the analytical
range of interest, should be chosen for injection
every day to determine day-to-day response
reproducibility.
12.1.3 If substantial nonlinearity is present in
the calibration curve a nonlinear least squares
fit (e.g. quadratic) should be employed.
This process involves fitting the data to
the following equation:
Y = A + BX + CX2
where
Y = peak area
X = quantity of component, nanograms
A,B, and C are coefficients in the equation
-------
T01-20
12.2 Analyte Concentrations
12.2.1
where
12.2.2
12.2.3
where
Analyte quantities on a sample cartridge are calculated
from the following equation:
YA = A + BXA +
YA is the area of the analyte characteristic ion for
the sample cartridge.
XA is the calculated quantity of analyte on the sample
cartridge, in nanograms.
A,B, and C are the coefficients calculated from the
calibration curve described in Section 12.1.3.
If instrumental response is essentially linear over the
concentration range of interest a linear equation
(C=0 in the equation above) can be employed.
Concentration of analyte in the original air sample is
calculated from the following equation:
CA=^
CA is the calculated concentration of analyte in
nanograms per liter.
V^ and XA are as previously defined in Section
10.2.10 and 12.2.1, respectively.
13. Standard Preparation
13.1 Direct Injection
13.1.1 This process involves preparation of a dilution
bottle containing the desired concentrations
of compounds of interest for direct injection
onto the GC/MS system.
-------
TO!-21
13.1.2 Fifteen three-millimeter diameter glass beads
and a one-inch Teflon stirbar are placed in a
clean two-liter glass septum capped bottle and
the exact volume is determined by weighing the
bottle before and after filling with deionized water.
The bottle is then rinsed with acetone and dried at 200°C.
13.1.3 The amount of each standard to be injected into the
vessel is calculated from the desired injection quantity
and volume using the following equation:
WT . WLX VB
Vl
where
WT is the total quantity of analyte to be injected
into the bottle in milligrams
MI is the desired weight of analyte to be injected
onto the GC/MS system or spiked cartridge in
nanograms
Vj is the desired GC/MS or cartridge injection
volume (should not exceed 500) in microliters.
VB is total volume of dilution bottle determined
in 13.1.1, in liters.
13.1.4 The volume of the neat standard to be injected
into the dilution bottle is determined using
the following equation:
W
where
Vj is the total volume of neat liquid to be injected
in microliters.
d is the density of the neat standard in grams per
milliliter.
-------
T01-22
13.1.6 The bottle is placed in a 60°C oven for at
least 30 minutes prior to removal of a vapor
phase standard.
13.1.7 To withdraw a standard for GC/MS injection
the bottle is removed from the oven and stirred
for 10-15 seconds. A suitable gas-tight microber
syring warmed to 60°C, is inserted through
the septum cap and pumped three times slowly.
The appropriate volume of sample (approximately 25%
larger than the desired injection volume) is drawn
into the syringe and the volume is adjusted to the
exact value desired and then immediately injected
over a 5-10 seconds period onto the GC/MS system as
described in Section 11.2.3.
13.2 Preparation of Spiked Cartridges by Vapor Phase Injection
13.2.1 This process involves preparation of a dilution
bottle containing the desired concentrations
of the compound(s) of interest as described
in 13.1 and injecting the desired volume of
vapor into a flowing inert gas stream directed
through a clean Tenax cartridge.
13.2.2 A helium purge system is assembled wherein
the helium flow 20-30 mL/minute is passed
through a stainless steel Tee fitted with
a septum injector. The clean Tenax cartridge
is connected downstream of the tee using
appropriate Swagelok fittings. Once the cartridge
is placed in the flowing gas stream the appropriate
volume vapor standard, in the dilution bottle,
is injected through the septum as described in
13.1.6. The syringe is flushed several times
by alternately filling the syringe with carrier
gas and displacing the contents into the flow
stream, without removing the syringe from the septum.
Carrier flow is maintain through the cartridge for
approximately 5 minutes after injection.
-------
TO!-23
13.3 Preparation of Spiked Traps Using Permeation or Diffusion
tubes
13.3.1 A flowing stream of inert gas containing known
amounts of each compound of interest is generated
according to ASTM Method 03609(6). Note that
a method of accuracy maintaining temperature
within + 0.1°C is required and the system
generally must be equilibrated for at least
48 hours before use.
13.3.2 An accurately known volume of the standard
gas stream (usually 0.1-1 liter) is drawn
through a clean Tenax cartridge using the
sampling system described in Section 10.2.1,
or a similar system. However, if mass flow
controllers are employed they must be calibrated
for the carrier gas used in Section 13.3.1
(usually nitrogen). Use of air as the carrier
gas for permeation systems is not recommended,
unless the compounds of interest are known
to be highly stable in air.
13.3.3 The spiked cartridges are then stored or immediately
analyzed as in Section 11.2.4.
14. Performance Criteria and Quality Assurance
This section summarizes quality assurance (QA) measures and
provides guidance concerning performance criteria which should be
achieved within each laboratory. In many cases the specific
QA procedures have been described within the appropriate section
describing the particular activity (e.g. parallel sampling).
-------
T01-24
14.1 Standard Opreating Procedures (SOPs)
14.1.1 Each user should generate SOPs describing the
following activities as they are performed
in their laboratory:
1) assembly, calibration, and operation of
the sampling system,
2) preparation, handling and storage of Tenax
cartridges,
3) assembly and operation of GC/MS system including
the thermal desorption apparatus and data
system, and
4) all aspects of data recording and processing.
14.1.2 SOPs should provide specific stepwise instructions
and should be readily available to, and understood
by the laboratory personnel conducting the
work.
14.2 Tenax Cartridge Preparation
14.2.1 Each batch of Tenax cartridges prepared (as
described in Section 9) should be checked for
contamination by analyzing one cartridge immediately
after preparation. While analysis can be accomplished
by GC/MS, many laboratories may chose to use
GC/FID due to logistical and cost considerations.
14.2.2 Analysis by GC/FID is accomplished as described
for GC/MS (Section 11) except for use of FID
detection.
-------
T01-25
14.2.3 While acceptance criteria can vary depending
on the components of interest, at a minimum
the clean cartridge should be demonstrated
to contain less than one fourth of the minimum
level of interest for each component. For
most compounds the blank level should be less
than 10 nanograms per cartridge in order to
be acceptable. More rigid criteria may be
adopted, if necessary, within a specific laboratory.
If a cartridge does not meet these acceptance
criteria the entire lot should be rejected.
14.3 Sample Collection
14.3.1 During each sampling event at least one clean
cartridge will accompany the samples to the
field and back to the laboratory, without being
used for sampling, to serve as a field blank.
The average amount of material found on the
field blank cartridge may be subtracted from
the amount found on the actual samples. However,
if the blank level is greater than 25% of the
sample amount, data for that component must
be identified as suspect.
14.3.2 During each sampling event at least one set
of parallel samples (two or more samples collected
simultaneously) will be collected, preferably
at different flow rates as described in Section
10.1. If agreement between parallel samples
is not generally within + 25% the user should
collect parallel samples on a much more frequent
basis (perhaps for all sampling points). If
a trend of lower apparent concentrations with
increasing flow rate is observed for a set
-------
TOT-26
of parallel samples one should consider using
a reduced flow rate and longer sampling interval
if possible. If this practice does not improve
the reproducibility further evaluation of the
method performance for the compound of interest
may be required.
14.3.3 Backup cartridges (two cartridges in series)
should be collected with each sampling event.
Backup cartridges should contain less than
20% of the amount of components of interest
found in the front cartridges, or be equivalent
to the blank cartridge level, whichever is
greater. The frequency of use of backup cartridges
should be increased if increased flow rate
is shown to yield reduced component levels
for parallel sampling. This practice will
help to identify problems arising from breakthrough
of the component of interest during sampling.
14.4 GC/MS Analysis
14.4.1 Performance criteria for MS tuning and mass
calibration have been discussed in Section
11.2 and Table 2. Additional criteria may
be used by the laboratory if desired. The
following sections provide performance guidance
and suggested criteria for determining the
acceptability of the GC/MS system.
14.4.2 Chromatographic efficiency should be evaluated
using spiked Tenax cartridges since this practice
tests the entire system. In general a reference
compound such as perfluorotoluene should be
spiked onto a cartridge at the 100 nanogram
level as described in Section 13.2 or 13.3.
The cartridge is then analyzed by GC/MS as
-------
TO!-27
described in Section 11.4. The perfluorotoluene (or
other reference compound) peak is then plotted on an
expanded time scale so that its width at 10% of the
peak can be calculated, as shown in Figure 6. The
width of the peak at 10% height should not exceed
10 seconds. More stringent criteria may be required
for certain applications. The assymmetry factor
(See Figure 6) should be between 0.8 and 2.0. The
assymmetry factor for any polar or reactive compounds
should be determined using the process described above,
If peaks are observed that exceed the peak width or
assymmetry factor criteria above, one should inspect
the entire system to determine if unswept zones or
cold spots are present in any of the fittings and
is necessary. Some laboratories may chose
to evaluate column performance separately by
direct injection of a test mixture onto the
GC column. Suitable schemes for column evaluation
have been reported in the literature (7).
Such schemes cannot be conducted by placing
the substances onto Tenax because many of
the compounds (e.g. acids, bases, alcohols)
contained in the test mix are not retained,
or degrade, on Tenax.
14.4.3 The system detection limit for each component
is calculated from the data obtained for
calibration standards. The detection limit
is defined as
DL = A + 3.3S
-------
T01-28
where
DL is the calculated detection limit in
nanograms injected.
A is the intercept calculated in Section
12.1.1 or 12.1.3.
S is the standard deviation of replicate
determinations of the lowest level standard
(at least three such determinations are
required.
In general the detection limit should be 20
nanograms or less and for many applications
detection limits of 1-5 nanograms may be required.
The lowest level standard should yield a signal
to noise ratio, from the total ion current response
of approximately 5.
14.4.4 The relative standard deviation for replicate
analyses of cartridges spiked at approximately
10 times the detection limit should be 20%
or less. Day to day relative standard deviation
should be 25% or less.
14.4.5 A useful performance evaluation step is the
use of an internal standard to track system
performance. This is accomplished by spiking
each cartridge, including blank, sample, and
calibration cartridges with approximately 100
nanograms of a compound not generally present
in ambient air (e.g. perfluorotoluene).. The
integrated ion intensity for this compound
helps to identify problems with a specific
sample. In general the user should calculate
the standard deviation of the internal standard
response for a given set of samples analyzed
under identical tuning and calibration conditions.
Any sample giving a value greater than + 2
standard deviations from the mean (calculated
-------
T01-29
excluding that particular sample) should be
identified as suspect. Any marked change 1n
Internal standard response may Indicate a need
for instrument recall oration.
-------
T01-30
REFERENCES
1. Krost, K. J., Pellizzari, E. D., Walburn, S. G., and Hubbard, S. A.,
Collection and Analysis of Hazardous Organic Emissions",
Analytical Chemistry. 54, 810-817, 1982.
2. Pellizzari, E. 0. and Bunch, J. E., "Ambient Air Carcinogenic Vapors-
Improved Sampling and Analytical Techniques and Field Studies",
EPA-600/2-79-081, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1979.
3. Kebbekus, B. B. and Bozzelli, J. W., "Collection and Analysis of
Selected Volatile Organic Compounds in Ambient Air", Proc Air
Pollution Control Assoc., Paper No. 82-65.2. Air Poll. Control
Assoc., Pittsburgh, Pennsylvania, 1982.
4. Riggin, R. M., "Technical Assistance Document for Sampling and
inalyo^ °M Iox!c Or9an1c Compounds in Ambient Air", EPA-600/
Protection Agency, Research
Walling, J F., Berkley, R. E., Swanson, D. H., and Toth, F. J.
EPAm600/7 M^°!iJ"fi0XS ?rgan1C ChemJ"l-Applications to Tenax",
EPA-600/7-54-82-059, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1982.
Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis"
American Society for Testing and Material, Philadelphia, '
Pennsylvania.
Grob, K., Jr., Grob, 6.,-and Grob, K., "Comprehensive Standardized
?U?J ?JoSt °r Gl3SS CaP111ary Columns", J. Chromatog., 156,
I —20,
-------
TO!-31
TABLE 1. RETENTION VOLUME ESTIMATES FOR COMPOUNDS ON TENAX
ESTIMATED RETENTION VOLUME AT
COMPOUND IQO'F (38°C)-LITERS/GRAM
19
Benzene
97
Toluene
Ethyl Benzene 20°
Xylene(s)
Cumene
20
n-Heptane
40
1-Heptene
g
Chloroform
Carbon Tetrachloride
1,2-Dichloroethane 10
1,1,1-Trichloroethane 6
on
Tetrcchloroethylene
?o
Trichloroethylene
30
1,2-Dichloropropane
QO
1,3-Dichloropropane
Chlorobenzene
Bromoform
Ethyl ene Di bromide 60
300
Bromobenzene
-------
TO!-32
TABLE 2. SUGGESTED PERFORMANCE CRITERIA FOR RELATIVE
ION ABUNDANCES FROM FC-43 MASS CALIBRATION
% RELATIVE
M/E ABUNDANCE
51 1.8 + 0.5
69 100
100 12.0+1.5
119 12.0+1.5
131 35.0+3.5
169 3.0 + 0.4
219 24.0+2.5
264 3.7 + 0.4
314 0.25 + 0.1
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T01-33
Tenax
~1.5 Grams (6 cm Bed Depth)
•GlassWool Plugs
• (0.5 cm Long)
Glass Cartridge
(13.5 mm OD x
100 mm Long)
\
.(a) Glass Cartridge
1/2" to
1/8"
Reducing
Glass Wool
Plugs
(0.5 cm Long)
1/8" End Cap,
Metal Cartridge
1/2" / (12.7 mm OD x
Swagelok Zjenax 100 mm Long)
Fitting ~i .5 Grams (7 cm Bed Depth)
(b) Metal Cartridge
FIGURE 1. TENAX CARTRIDGE DESIGNS
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TO!-34
Teflon
Compression
SM!
Purge
Gas
Cavity for •
Tanax
Cartridge
Latch for
Compression
Seal
Effluent to
6-Port Valve
To GC/MS
Vent
Liquid
Nitrogen
Coolant
Ql
(a) Qlass Cartridges (Compression Fit)
Purge
SwagaJok
End Fittings
Tenax
Trap
Heated
Block
Carrier
Gas
Liquid
Nitrogen
Coolant
(b) Metal Cartridges (Swagelok Fittings)
FIGURE 2. TENAX CARTRIDGE DESORPTION MODULES
-------
T01-35
Vent
Couplings
to Connect
Tenax
Cartridge*
1—-D
Mass Flow
Controllers
(a) Mass Flow Control
Rotometer
Vent
Dry
Test
Meter
^•B
•BHH
T
L
V
Needle
Valve
Pump
Coupling to
Connect Tenax
Cartridge
(b) Needle Valve Control
FIGURE 3. TYPICAL SAMPLING SYSTEM CONFIGURATIONS
-------
TO!-36
SAMPLING DATA SHEET
(One Sarole Per Data Sheet)
PROJECT:
SITE:
DATE(S) SAMPLED:
LOCATION:
TIME PERIOD SAMPLED:,
OPERATOR:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
CALIBRATED BY:
Sample Number:
Start Time:
Stop Time:
Time
1.
2.
-in i
3.
4.
N.
Dry Gas
Meter
Reading
— ' '
Rotameter
Reading
Flow
Rate,*Q
ml/Min
1
Ambient
Temperature
°C
Barometric
Pressure,
mtnHg
— — — -^— — — — >— __
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
= Ql + 0.2 + Q3---O.N
iuuu x (Sampling Hme in Minutes) =
Liters
Liters
**
Use data from dry gas meter if available.
FIGURE 4. EXAMPLE SAMPLING DATA SHEET
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TO!-37
Thermal
DMorption
Chamber
6-Port High-Temperature
Valva
Capillary
Gat
Chromatograph
Mass
Spectrometer
Data
System
Carrier
Gas
Vent
Freeze Out Loop
Liquid
Nitrogen
Coolant
FIGURE 5
. BLOCK DIAGRAM OF ANALYTICAL SYSTEM
-------
TO!-38
Asymmetry Factor -
AB
Example Calculation:
Peak Height - DE * 100 mm
10% Peak Height - BD - 10 mm
P«ak Width at 10% Peak Height - AC - 23 mm
AB- 11 mm
BC *12mm
Therefore: Asymmetry Factor - ~ -1.1
FIGURE 6. PEAK ASYMMETRY CALCULATION
-------
METHOD T02 Revision 1.0
April, 1984
METHOD FOR THE DETERMINATION OF VOLATILE ORGAN^ IN
AMBIENT AIR BY CARBON MOLECULAR SIEVE ADSORPTION AND
GAS CHROMATOGRAPHY/MASS SPECTROMETRY (GC/MS)
1. Scope
1.1 This document describes a procedure for collection and
determination of selected volatile organic compounds
which can be captured on carbon molecular sieve (CMS)
adsorbents and determined by thermal desorption GC/MS
techniques.
1.2 Compounds which can be determined by this method are
nonpolar and nonreactive organics having boiling points
in the range -15 to +120°C. However, not all compounds
meeting these criteria can be determined. Compounds for
which the performance of the method has been documented
are listed in Table 1. The method may be extended to
other compounds but additional Validation by the user
is required. This method has bj;en extensively used in
a single laboratory. Consequently, its general applicability
has not been thoroughly documented.
2. Applicable Documents
2.1 ASTM Standards
D 1356 Definitions of Terms Related to Atmospheric Sampling
and Analysis.
E 355 Recommended Practice for Gas Chromatography Terms
and Relationships.
2.2 Other Documents
Ambient Air Studies (1,2).
U.S. EPA Technical Assistance
Document (3).
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T02-2
3. Summary of Method
3.1 Ambient air is drawn through a cartridge containing ^0.4
of a carbon molecular sieve (CMS) adsorbent. Volatile
organic compounds are captured on the adsorbent while
major inorganic atmospheric constituents pass through
(or are only partially retained). After sampling, the
cartridge is returned to the laboratory for analysis.
3.2 Prior to analysis the cartridge is purged with 2-3 liters of
pure, dry air (in the same direction as sample flow) to
remove adsorbed moisture.
3.3 For analysis the cartridge is heated to 350°-400°C, under
helium purge and the desorbed organic compounds are
collected in a specially designed cryogenic trap. The
collected organics are then flash evaporated onto a
capillary column GC/MS system (held at -70°C). The
individual components are identified and quantified during
a temperature programmed chromatographic run.
3.4 Due to the complexity of ambient air samples, only high
resolution (capillary column) GC techniques are
acceptable for most applications of the method.
4. Significance
4.1 Volatile organic compounds are emitted into the atmosphere
from a variety of sources including industrial and commercial
facilities, hazardous waste storage and treatment facilities,
etc. Many of these compounds are toxic; hence knowledge of
the concentration of such materials in the ambient atmosphere
is required in order to determine human health impacts.
4.2 Traditionally air monitoring methods for volatile organic
compounds have relied on carbon adsorption followed by
solvent desorption and GC analysis. Unfortunately, such
methods are not sufficiently sensitive for ambient air
monitoring, in most cases, because only a small portion of
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T02-3
the sample is injected onto the GC system. Recently on-line
thermal desorption methods, using organic polymeric adsorbents
such as Tenax® GC, have been used for ambient air monitoring.
The current method uses CMS adsorbents (e.g. Spherocarb®)
to capture highly volatile organics (e.g. vinyl chloride)
which are not collected on Tenax®. The use of on-line thermal
desorption GC/MS yields a sensitive, specific analysis
procedure.
5. Definitions
(
Definitions used in this document and any user prepared SOPs should
be consistent with ASTM D1356 (4). All abbreviations and symbols
are defined with this document at the point of use.
6. Interferences
6.1 Only compounds having a mass spectrum and GC retention
time similar to the compound of interest will interfere
in the method. The most commonly encountered interferences
are structural isomers.
6.2 Contamination of the CMS cartridge with the compound(s)
of interest can be a problem in the method. The user must
be careful in the preparation, storage, and handling of the
cartridges through the entire process to minimize contamination.
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T02-4
7. Apparatus
7.1 Gas Chromatograph/Mass Spectrometry system - must be capable
of subambient temperature programming. Unit mass resolution
to 800 amu. Capable of scanning 30-300 amu region every
0.5-0.8 seconds. Equipped with data system for instrument
control as well as data acquisition, processing and storage.
7.2 Thermal Desorption Injection Unit - Designed to accommodate
CMS cartridges in use (See Figure 3) and including cryogenic
trap (Figure 5) and injection valve (Carle Model 5621
or equivalent).
7.3 Sampling System - Capable of accurately and precisely
drawing an air flow of 10-500 ml/minute through the CMS
cartridge. (See Figure 2a or b.)
7.4 Dewar flasks - 500 ml and 5 liter.
7.5 Stopwatches.
7.6 Various pressure regulators and valves - for connecting
compressed gas cylinders to GC/MS system.
7.7 Calibration gas - In aluminum cylinder. Prepared by
user or vendor. For GC/MS calibration.
7.8 High pressure apparatus for preparing calibration gas
cylinders (if conducted by user). Alternatively, custom
prepared gas mixtures can be purchased from gas supply
vendors.
7.9 Friction top can (e.g. one-gallon paint can) - With layer
of activated charcoal to hold clean CMS cartridges.
7.. 10 Thermometer - to record ambient temperature.
7.11 Barometer (optional).
7.12 Dilution bottle - Two-liter with septum cap for standard
preparation.
7.13 Teflon stirbar - 1 inch long
7.14 Gas tight syringes - 10-500 ul for standard injection onto
GC/MS system and CMS cartridges.
7.15 Liquid microliter syringes - 5-50 uL for injecting neat
liquid standards into dilution bottle.
7.16 Oven - 60 + 5°C for equilibrating dilution bottle.
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T02-5
7.17 Magnetic stirrer.
7.18 Variable voltage transformers - (120 V and 1000 VA) and
electrical connectors (or temperature controllers) to
heat cartridge and cryogenic loop.
7.19 Digital pyrometer - 30 to 500°C range.
7.20 Soap bubble flow meter - 1, 10 and 100 ml calibration
points.
7.21 Copper tubing (1/8 inch) and fittings for gas inlet lines.
7.22 GC column - SE-30 or alternative coating, glass capillary
or fused silica.
7.23 Psychrometer (optional).
7.24 Filter holder - stainless steel or aluminum (to accommodate
1 inch diameter filter). Other sizes may be used if
desired, (optional)
8. Reagents and Materials
8.1 Empty CMS cartridges - Nickel or stainless steel (See
Figure 1).
8.2 CMS Adsorbent, 60/80 mesh- Spherocarb® from Analabs Inc.,
or equivalent.
8.3 Glasswool - silanized.
8.4 Methylene chloride - pesticide quality, or equivalent.
8.5 Gas purifier cartridge for purge and GC carrier gas
containing charcoal, molecular sieves, and a drying
agent. Available from various chromatography supply
houses.
8.6 Helium - Ultra pure, (99.9999%) compressed gas.
8.7 Nitrogen - Ultra pure, (99.9999%) compressed gas.
8.8 Liquid nitrogen or argon (50 liter dewar).
8.9 Compressed air, if required - for operation of GC oven
door.
8.10 Perf1uorotributyl amine (FC-43) for GC/MS calibration.
" 8.11 Chemical Standards - Neat compounds of interest. Highest
purity available.
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T02-6
9. Cartridge Construction and Preparation
9.1 A suitable cartridge design in shown in Figure 1. Alternate
designs have been reported (1) and are acceptable, provided
the user documents their performance. The design shown in
Figure 1 has a built-in heater assembly. Many users may
choose to replace this heater design with a suitable
separate heating block or oven to simplify the cartridge
design.
9.2 The cartridge is assembled as shown in Figure 1 using
standard 0.25 inch O.D. tubing (stainless steel or nickel),
1/4 inch to 1/8 inch reducing unions, 1/8 inch nuts,
ferrules, and endcaps. These parts are rinsed with
methylene chloride and heated at 250°C for 1 hour prior
to assembly.
9.3 The thermocouple bead is fixed to the cartridge body, and
insulated with a layer of Teflon tape. The heater wire
(constructed from a length of thermocouple wire) is wound
around the length of the cartridge and wrapped with Teflon
tape to secure the wire in place. The cartridge is then
wrapped with woven silica fiber insulation (Zetex or
equivalent). Finally the entire assembly is wrapped with
fiber glass tape.
9.4 After assembly one end of the cartridge is marked with
a serial number to designate the cartridge inlet during
sample collection.
9.5 The cartridges are then packed with ^0.4 grams .of CMS
adsorbent. Glasswool plugs (-vO.5 inches long) are placed
at each end of the cartridge to hold the adsorbent firmly
in place. Care must be taken to insure that no strands
of glasswool extend outside the tubing, thus causing
leakage in the compression endfittings. After loading the
endfittings (reducing unions and end caps) are tightened
onto the cartridge.
-------
T02-7
9.6 The cartridges are conditioned for initial use by heating
at 400°C overnight (at least 16 hours) with a 100 mL/minute
purge of pure nitrogen. Reused cartridges need only to be
heated for 4 hours and should be reanalyzed before use to
ensure complete desorption of impurities.
9.7 For cartridge conditioning ultra-pure nitrogen gas is passed
through a gas purifier to remove oxygen.moisture and organic
contaminants. The nitrogen supply is connected to the
unmarked end of the cartridge and the flow adjusted to
•v50 mL/minute using a needle valve. The gas flow from the
inlet (marked) end of the cartridge is vented to the atmosphere.
9.8 The cartridge thermocouple lead is connected to a pyrometer
and the heater lead is connected to a variable voltage
transformer (Variac) set at 0 V. The voltage on the Variac
is increased to ^15 V and adjusted over a 3-4 minute period
to stabilize the cartridge temperature at 380-400°C.
9.9 After 10-16 hours of heating (for new cartridges) the
Variac is turned off and the cartridge is allowed to cool
to <30°C, under continuing nitrogen flow.
9.10 The exit end of the cartridge is capped and then the entire
cartridge is removed from the flow line and the other endcap
immediately installed. The cartridges are then placed in a
metal friction top (paint) can containing ^2 inches of gran-
ulated activated charcoal (to prevent contamination of the
cartridges during storage) in the bottom, beneath a retaining
screen. Clean paper tissues (e.g. Kimwipes ) are placed in
can to avoid damage to the cartridges during shipment.
9.11 Cartridges are stored in the metal can at all times except
when in use. Adhesives initially present in the cartridge
insulating materials are "burnt off" during initial condition-
ing. Therefore, unconditioned cartridges should not be placed
in the metal can since they may contaminate the other
cartridges.
9.12 Cartridges are conditioned within two weeks of use. A blank
from each set of cartridges is analyzed prior to use in field
-------
T02-8
sampling. If an acceptable blank level is achieved, that
batch of cartridges (including the cartridge serving as the
blank) can be used for field sampling.
10. Sampling
10.1 Flow Rate and Total Volume Selection
10.1.1 Each compound has a characteristic retention
volume (liters of air per unit weight of
adsorbent). However, all Of the compounds listed
in Table 1 have retention volumes (at 37°C) in
excess of 100 liters/cartridge (0.4 gram CMS
cartridge) except vinyl chloride for which the
value is *30 liters/cartridge. Consequently, if
vinyl chloride or similarly volatile compounds are
of concern the maximum allowable sampling volume
is approximately 20 liters. If such highly volatile
compounds are not of concern, samples as large as
100 liters can be collected.
10.1.2 To calculate the maximum allowable sampling flow
rate the following equation can be used:
^ax-
where
QMax 1s the calculated maximum sampling
rate in mL/minute.
t is the desired sampling time in minutes.
VMax 1s the maximum allowable total volume
based on the discussion in 10.1.1.
10.1.3 For the cartridge design shown in Figure 1 QMax
should be between 20 and 500 mL/minute. If QMax
lies outside this range the sampling time or total
sampling volume must be adjusted so that this
criterion is achieved.
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T02-9
10.1.4 The flow rate calculated in 10.1.3 defines the
maximum allowable flew rate. In general, the
user should collect additional samples in parallel,
at successive 2- to 4-fold lower flow rates. This
practice serves as a quality control procedure to
check on component breakthrough and related sampling
and adsorption problems, and is further discussed
in the literature (5).
10.2 Sample Collection
10.2.1 Collection of an accurately known volume of air
is critical to the accuracy of the results. For
this reason the use of mass flow controllers, rather
than conventional needle valves or orifices is highly
recommended, especially at low flow rates (e.g. less
than 100 milliliters/minute). Figure 2a illustrates
a sampling system based on mass flow controllers
which readily allows for collection of parallel samples.
Figure 2b shows a commercially available sampling system
based on needle valve flow controllers.
10.2.2 Prior to sample collection the sampling flow rate is
calibrated near the value used for sampling, with a
"dummy" CMS cartridge in place. Generally calibration
is accomplished using a soap bubble flow meter or
calibrated wet test meter connected to the flow exit,
assuming the entire flow system is sealed. ASTM
Method D 3686 (4) describes an appropriate calibration
scheme, not requiring a sealed flow system downstream
of the pump.
10.2.3 The flow rate should be checked before and after each
sample collection. Ideally, a rotemeter or mass flow
meter should be included in the sampling system to
allow periodic observation of the flow rate without
disrupting the sampling process.
-------
T02-10
10.2.4 To collect an air sample the cartridges are removed
from the sealed container just prior to initiation of
the collection process.
.10.2.5 The exit (unmarked) end of the cartridge is connected
to the sampling apparatus. The endcap is left on the
sample inlet and the entire system is leak checked by
activating the sampling pump and observing that no flow
is obtained over a 1 minute period. The sampling
pump is then shut off.
10.2.6 The endcap is removed from the cartridge, a particulate
filter and holder are placed on the inlet end of the
cartridge, and the sampling pump is started. In many
situations a particulate filter is not necessary since
the compounds of interest are in the vapor state. How-
ever, if, large amounts of particulate matter are
encountered, the filter may be useful to prevent con-
tamination of the cartridge. The following parameters
are recorded on an appropriate data sheet (Figure 4):
date, sampling location, time, ambient temperature,
barometric pressure, relative humidity, dry gas meter
reading (if applicable), flow rate, rotometer reading
(if applicable), cartridge number, pump, and dry gas
meter serial number.
10.2.7 The samples are collected for the desired time,
periodically recording the variables listed above. At
the end of the sampling period the parameters listed
in 10.2.6 are recorded and the flow rate is checked.
If the flows at the beginning and end of the sampling
period differ by more than 10%, the cartridge should
be marked as suspect.
10.2.8 The cartridges are removed (one at a time), the
endcaps are replaced, and the cartridges are placed
into the original container. The friction top can
is sealed and packaged for immediate shipment to the
analytical laboratory.
-------
102-11
10.2.9 The average sample rate is calculated and recorded
for each cartridge according to the following equation:
where
Q. = Average flow rate in ml /minute.
0, , Q2,...QN = Flow rates determined
beginning, end, and immediate points
during sampling.
N = Number of points averaged.
10.2.10 The total volumetric flow is obtained directly from
the dry gas meter or calculated and recorded for
each cartridge using the following equation:
TxQ.
V =
m
where
1UOTJ
V = Total volume sampled in liters at measured
m
temperature and pressure.
T = Sampling time = T2-T-j, minutes.
10.2.11 The total volume sampled (Vs) at standard conditions,
760 mm Hg and 25°C, is calculated from the following
equation:
Vs = Vm x 760 x 273
ta
where
Pa = Average barometric pressure, mm Hg
ta = Average ambient temperature, °C.
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T02-12
11. Sample Analysis
11.1 Sample Purging
11.1.1 Prior to analysis all samples are purged at room
temperature with pure, dry air or nitrogen to remove
water vapor. Purging is accomplished as described
in 9.7 except that the gas flow is in the same direction
as sample flow (i.e. marked end of cartridge is
connected to the flow system).
11.1.2 The sample is purged at 500 mL/minute for 5 minutes.
After purging the endcaps are immediately replaced.
The cartridges are returned to the metal can or
analyzed immediately.
11:1.3 If very humid air is being sampled the purge time
may be increased to more efficiently remove water
vapor. However, the sum of sample volume and purge
volume must be less than 75% of the retention volume for
the most volatile component of interest.
11.2 GC/MS Setup
11.2.1 Considerable variation from one laboratory to another
is expected in terms of instrument configuration.
Therefore, each laboratory must be responsible for
verifying that their particular system yields satis-
factory results. Section 14 discusses specific
performance criteria which should be met.
11.2.2 A block diagram of the analytical system required
for analysis of CMS cartridges is depicted in Figure 3.
The thermal desorption system must be designed to
accommodate the particular cartridge configuration.
For the CMS cartridge design shown in Figure 1, the
cartridge heating is accomplished as described in 9.8.
The use of a desorption oven, in conjunction with a
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T02-13
simplier cartridge design is also acceptable. Exposure
of the sample to metal surfaces should be minimized and
only stainless steel or nickel should be employed.
The volume of tubing leading from the cartridge to
the GC column must be minimized and all areas must
be well-swept by helium carrier gas.
11.2.3 The GC column oven must be capable of being cooled to
-70°C and subsequently temperature programmed to 150°C.
11.2.4 The specific GC column and temperature program employed
will be dependent on the compounds of interest. Appro-
priate conditions are described in the literature (2).
In general, a nonpolar stationary phase (e.g. SE-30,
OV-1) temperature programmed from -70 to 150°C at 8°/
minute will be suitable. Fused silica, bonded-phase
columns are preferable to glass columns since they are
more rugged and can be inserted directly into the MS
ion source, thereby eliminating the need for a GC/MS
transfer line. Fused silica columns are also more
readily connected to the GC injection valve (Figure 3).
A drawback of fused silica, bonded-phase columns is the
lower capacity compared to coated, glass capillary
columns. In most cases the column capacity will be less
than 1 microgram injected for fused silica columns.
11.2.5 Capillary column dimensions of 0.3 mm ID and 50 meters
long are generally appropriate although shorter lengths
may be sufficient in many cases.
11.2.6 Prior to instrument calibration or sample analysis the
GC/MS system is assembled as shown in Figure 3. Helium
purge flow (through the cartridge) and carrier flow are
set at approximately 50 mL/minute and 2-3 mL/minute
respectively. When a cartridge is not in place a union
is placed in the helium purge line to ensure a continuous
inert gas flow through the injection loop.
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T02-14
11.2.7 Once the column and other system components are assembled
and the various flows established the column temperature
is increased to 250°C for approximately four hours (or
overnight if desired) to condition the column.
11.2.8 The MS and data system are set up according to the
manufacturer's instructions. Electron impact ionization
(70eV) and an electron multiplier gain of approximately
5 x 10 should be employed. Once the entire GC/MS
system has been setup the system is calibrated as described
in Section 11.3. The user should prepare a detailed
standard operating procedure (SOP) describing this process
for the particular instrument being used.
11.3 GC/MS Calibration
11.3.1 Tuning and mass standardization of the MS system is per-
formed according to manufacturer's instructions
and relevant user prepared SOPs. Perfluorotributyl amine
(FC-43) should generally be employed as the reference
compound. The material is introduced directly into the
ion source through a molecular leak. The instrumental
parameters (e.g., lens voltages, resolution, etc.)
should be adjusted to give the relative ion abundances
shown in Table 2, as well as acceptable resolution and
peak shape. If these approximate relative abundances
cannot be achieved, the ion source may require cleaning
according to manufacturer's instructions. In the event
that the user's instrument cannot achieve these relative
ion abundances, but is otherwise operating properly,
the user may adopt another set of relative abundances
as performance criteria. However, these alternate
values must be repeatable on a day-to-day basis.
-------
T02-15
11.3.2 After the mass standardization and tuning process has
been completed and the appropriate values entered into
the data system, the user should then calibrate the
entire GC/MS system by introducing known quantities
of the components of interest into the system. Three
alternate procedures may be employed for the calibra-
tion process including 1) direct injection of dilute
vapor phase standards, prepared in a dilution bottle
or compressed gas cylinder, onto the GC column,
2) injection of dilute vapor phase standards into a
flowing inert gas stream directed onto a CMS cartridge,
and 3) introduction of permeation or diffusion tube
standards onto a CMS cartridge. Direct injection of a
compressed gas cylinder (aluminum) standard containing
trace levels of the compounds of interest has been found
to be the most convenient practice since such standards
are stable over a several month period. The standards
preparation processes for the various approaches are
described in Section 13. The following paragraphs
describe the instrument calibration process for these
approaches.
11.3.3 If the system is to be calibrated by direct injection
of a vapor phase standard, the standard, in either a
compressed gas cylinder or dilution flask, is obtained
as described in Section 13. The MS and data system
are setup for acquisition, but the ionizer filament
is shut off. The GC column oven is cooled to -70°C,
the injection valve is placed in the load mode, and the
cryogenic loop is immersed in liquid nitrogen or liquid
argon. Liquid argon is required for standards prepared
in nitrogen or air, but not for standards prepared in
helium. A known volume of the standard (10-1000 ml)
is injected through the cryogenic loop at a rate of
10-100 mL/minute.
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T02-16
11.3.4 Immediately after loading the vapor phase standard, the
injection valve is placed in the inject mode, the GC
program and system clock are started, and the cryogenic
loop is heated to 60°C by applying voltage (15-20 volts)
to the thermocouple wire heater surrounding the loop.
The voltage is adjusted to maintain a loop temperature
of 60°C. An automatic temperature controller can be
used in place of the manual control system. After
elution of unretained components «3 minutes after
injection) the ionizer filament is turned on and data
acquisition is initiated. The helium purge line (set
at 50 mL/minute) is connected to the injection valve
and the valve is returned to the load mode. The loop
temperature is increased to 150°C, with helium purge,
and held at this temperature until the next sample is
to be loaded.
11.3.5 After the last component of interest has eluted,
acquisition is terminated and the data is processed as
described in Section 11.3.8. The standard injection
process is repeated using different standard concentra-
tions and/or volumes to cover the analytical range of
interest.
11.3.6 If the system is to be calibrated by analysis of
standard CMS cartridges, a series of cartridges is
prepared as described in Sections 13.2 or 13.3. Prior
to analysis the cartridges are stored (no longer than
48 hours) as described in Section 9.10. For analysis
the injection valve is placed in the load mode and the
cryogenic loop is immersed in liquid nitrogen (or
liquid argon if desired). The CMS cartridge is installed
in the helium purge line (set at 50 mL/minute) so that
the helium flow through the cartridge is opposite to
the direction of sample flow and the purge gas is
directed through the cryogenic loop and vented to the
-------
T02-17
atmosphere. The CMS cartridge is heated to 370-400°C
and maintained at this temperature for 10 minutes (using
the temperature control process described in Section 9.8).
During the desorption period, the GC column oven is
cooled to -70°C and the MS and data system are setup for
acquisition, but the ionizer filament is turned off.
11.3.7 At the end of the 10 minute desorption period, the ana-
lytical process described in Sections 11.3.4 and 11.3.5
is conducted. During the GC/MS analysis heating of the
CMS cartridge is discontinued. Helium flow is maintained
through the CMS cartridge and cryogenic loop until the
cartridge has cooled to room temperature. At that time,
the cryogenic loop is allowed to cool to room temperature
and the system is ready for further cartridge analysis.
Helium flow is maintained through the cryogenic loop at
all times, except during the installation or removal of
a CMS cartridge, to minimize contamination of the loop.
11.3.8 Data processing for instrument calibration involves
determining retention times, and integrated characteristic
ion intensities for each of the compounds of interest.
In addition, for at least one chromatographic run, the
individual mass spectra should be inspected and compared
to reference spectra to ensure proper instrumental
performance. Since the steps involved in data processing
are highly instrument specific,, the user should prepare
a SOP describing the process for individual use. Overall
performance criteria for instrument calibration are
provided in Section 14. If these criteria are not
achieved, the user should refine the instrumental
parameters and/or operating procedures to meet these
criteria.
11.4 Sample Analysis
11.4.1 The sample analysis is identical to that described
in Sections 11.3.6 and 11.3.7 for the analysis of
standard CMS cartridges.
-------
T02-18
11.4.2 Data processing for sample data generally involves
1) qualitatively determining the presence or absence
of each component of interest on the basis of a set
of characteristic ions and the retention time using
a reversed-search software routine, 2) quantification
of each identified component by integrating the intensity
of a characteristic ion and comparing the value to
that of the calibration standard, and 3) tentative
identification of other components observed using a
forward (library) search software routine. As for
other user specific processes, a SOP should be prepared
describing the specific operations for each individual
laboratory.
12. Calculations
12.1 Calibration Response Factors
12.1.1 Data from calibration standards is used to calculate a
response factor for each component of interest.
Ideally the process involves analysis of at least three
calibration levels of each component during a given
day and determination of the response factor (area/
nanogram injected) from the linear least squares
fit of a plot of nanograms injected versus area
(for the characteristic ion). In general, quantities
of components greater than 1,000 nanograms should not
be injected because of column overloading and/or MS
response nonlinearity.
12.1.2 In practice the daily routine may not always allow
analysis of three such calibration standards. In
this situation calibration data from consecutive days
may be pooled to yield a response factor, provided
that analysis of replicate standards of the same
concentration are shown to agree within 20* on the
consecutive days. In all cases one given standard
-------
T02-19
concentration, near the midpoint of the analytical
range of interest, should be injected at least once
each day to determine day-to-day precision of response
factors.
12.1.3 Since substantial nonlinearity may be present in the
calibration curve, a nonlinear least squares fit
(e.g. quadratic) should be employed. This process
involves fitting the data to the following equation:
where
Y = A + BX + CX2
Y = peak area
X - quantity of component injected nanograms
A, B, and C are coefficients in the equation.
12.2 Analyte Concentrations
12.2.1 Analyte quantities on a sample cartridge are calculated
from the following equation:
YA = A + BXA + CX2
where Y. is the area of the analyte characteristic ion for
M
the sample cartridge.
XA is the calculated quantity of analyte on the sample
cartridge, in nanograms.
A, B, and C are the coefficients calculated from the
calibration curve described in Section 12.1.3.
12.2.2 If instrumental response is essentially linear over the
concentration range of interest, a linear equation
(C=0 in the equation above) can be employed.
-------
T02-20
12.2.3 Concentration of analyte in the original air sample
is calculated from the following equation:
where
CA is the calculated concentration of analyte in ng/L.
Vs and XA are as previously defined in Section 10.2.11
and 12.2.1, respectively.
13. Standard Preparation
13.1 Standards for Direct Injection
13.1.1 Standards for direct injection can be prepared in
compressed gas cylinders or in dilution vessels.
The dilution flask protocol has been described in
detail in another method and is not repeated here (6).
For the CMS method where only volatile compounds
(boiling point <120°C) are of concern, the preparation
of dilute standards in 15 liter aluminum compressed
gas cylinders has been found to be most convenient.
These standards are generally stable over at least a
3-4 month period and in some cases can be purchased
from commercial suppliers on a custom prepared basis.
13.1.2 Preparation of compressed gas cylinders requires
working with high pressure tubing and fittings, thus
requiring a user prepared SOP which ensures that
adequate safety precautions are taken. Basically,
the preparation process Involves injecting a pre-
determined amount of neat liquid or gas into an
empty high pressure cylinder of known volume, using
gas flow into the cylinder to complete the transfer.
-------
T02-21
The cylinder is then pressurized to a given value
(500-10QO psi). The final cylinder pressure must be
determined using a high precision gauge after the
cylinder has thermally equilibrated for a 1-2 hour
period after filling.
13.1.2 The concentration of components in the cylinder
standard should be determined by comparison with
National Bureau of Standards reference standards
(e.g. SRM 1805-benzene in nitrogen) when available.
13.1.3 The theoretical concentration (at 25°C and 760 mm
pressure) for preparation of cylinder standards
can be calculated using the following equation:
C = VI x d 14.7 x 24.4 x 1000
T vx Pc + 14.7
where CT is the component concentration, in ng/mL at 25°C
and 760 mm Hg pressure.
V is the volume of neat liquid component injected,
in yL.
Vc is the internal volume of the cylinder, in I..
d is the density of the neat liquid component,
in g/nt.
p is the final pressure of the cylinder standards,
in pounds per square inch gauge (psig).
13.2 Preparation of Spiked Traps by Vapor Phase Injection
This process involves preparation of a dilution flask
or compressed gas cylinder containing the desired concentra-
tions of the compound(s) of interest and injecting the desired
volume of vapor into a flowing gas stream which is directed
onto a clean CMS cartridge. The procedure is described in
detail in another method within the Compendium (6) and will not be
repeated here.
-------
T02-22
13.3 Preparation of Spiked Traps Using Permeation or Diffusion Tubes
.13.3.1 A flowing stream of inert gas containing known amounts
of each compound of interest is generated according
to ASTM Method D3609 (4). Note that a method of
accurately maintaining temperature within + 0.1°C is
required and the system generally must be equilibrated
for at least 48 hours before use.
13.3.2 An accurately known volume of the standard gas stream
(usually 0.1-1 liter) is drawn through a clean CMS
cartridge using the sampling system described in
Section 10.2.1, or a similar system. However, if mass
flow controllers are employed, they must be calibrated
for the carrier gas used in Section 13.3.1 (usually
nitrogen). Use of air as the carrier gas for permeation
systems is not recommended, unless the compounds of
interest are known to be highly stable in air.
13.3.3 The spiked traps are then stored or immediately
analyzed as in Sections 11.3.6 and 11.3.7.
14. Performance Criteria and Quality Assurance
This section summarizes the quality assurance (QA) measures and
provides guidance concerning performance criteria which should be
achieved within each laboratory. In many cases the specific QA
procedures have been described within the appropriate section
describing the particular activity (e.g. parallel sampling).
14.1 Standard Operating Procedures (SOPs)
14.1.1 Each user should generate SOPs describing the following
activities as accomplished in their laboratory:
1) assembly, calibration and operation of the sampling
system, 2) preparation, handling and storage of CMS
cartridges, 3) assembly and operation of 6C/MS system
including the thermal desorption apparatus and data
system, and 4) all aspects of data recording and processing.
-------
T02-23
14.1.2 SOPs should provide specific stepwise instructions and
should be readily available to, and understood by the
laboratory personnel conducting the work.
14.2 CMS Cartridge Preparation
14.2.1 Each batch of CMS cartridges, prepared as described in
Section 9, should be checked for contamination by
analyzing one cartridge, immediately after preparation.
While analysis can be accomplished by GC/MS, many
laboratories may chose to use GC/FID due to logistical
and cost considerations.
14.2.2 Analysis by GC/FID is accomplished as described for
GC/MS (Section 11) except for use of FID detection.
14.2.3 While acceptance criteria can vary depending on the
components of interest, at a minimum the clean
cartridge should be demonstrated to contain less than
one-fourth of the minimum level of interest for each
component. For most compounds the blank level should
be less than 10 nanograms per cartridge in order to be
acceptable. More rigid criteria may be adopted, if
necessary, within a specific laboratory. If a cartridge
does not meet these acceptance criteria, the entire lot.
should be rejected.
14.3 Sample Collection
14.3,1 During each sampling event at least one clean cartridge
will accompany the samples to the field and back to the
laboratory, having been placed in the sampler but without
sampling air, to serve as a field blank. The average
amount of material found on the field blank cartridges
may be subtracted from the amount found on the actual
samples. However, if the blank level is greater than
-------
T02-24
25% of the sample amount, data for that component
must be identified as suspect.
14.3.2 During each sampling event at least one set of
parallel samples (two or more samples collected
simultaneously) should be collected, preferably at
different flow rates as described in Section 10.1.4.
If agreement between parallel samples is not generally
within +25% the user should collect parallel samples
on a much more frequent basis (perhaps for all sampling
points). If a trend of lower apparent concentrations
with increasing flow rate is observed for a set of
parallel samples one should consider usvig a reduced
sampling rate and longer sampling interval, if possible.
If this practice does not improve the reproducibility
further evaluation of the method performance for the
compound of interest might be required.
14.3.3 Backup cartridges (two cartridges in series) should be
collected with each sampling event. Backup cartridges
should contain less than 10% of the amount of components
of interest found in the front cartridges, or be equiva-
lent to the blank cartridge level, whichever is greater.
14.4 6C/MS Analysis
14.4.1 Performance criteria for MS tuning and mass standardiza-
tion have been discussed in Section 11.2 and Table 2.
Additional criteria can be used by the laboratory,
if desired. The following sections provide performance
guidance and suggested criteria for determining the
acceptability of the GC/MS system.
-------
T02-25
14 4.2 Chromatographic efficiency should be evaluated daily
by the injection of calibration standards. A reference
compound(s) should be chosen from the calibration
standard and plotted on an expanded time scale so that
its width at 10* of the peak height can be calculated,
as shown in Figure 6. The width of the peak at 10%
height should not exceed 10 seconds. More stringent
criteria may be required for certain applications.
The asytrmetry factor (see Figure 6) should be between
0 8 and' 2.0. The user should also evaluate chroma-
tographic perfonnance for any polar or reactive compounds
of interest, using the process described above. If peaks
are observed that exceed the peak width or asymmetry
factor criteria above, one should inspect the entire
system to determine if unswept zones or cold spots are
fittings or tubing and/or if
column is required. Some labora-
valuate column performance separately
present in any of the
replacement of the GC
tories may chose to
by direct injection If a test mixture onto the GC
column. Suitable scUes for column evaluation have been
reported in the literature (7).
For each component is calculated
ed for calibration standards. The
efined as
14.4.3 The detection limit
from the data obtain
detection limit is d
DL s A + 3.3S
where
DL is the calculated detection limit in nanograms
injected.
A is the intercept calculated in Section 12.1.3.
S is the standard deviation of replicate determina-
tions of the lowest level standard (at least three
such determinates are required). The lowest
-------
T02-26
level standard should yield a signal to noise ratio
(from the total ion current response) of approximately 5.
14.4.4 The relative standard deviation for replicate analyses
of cartridges spiked at approximately 10 times the
detection limit should be 20% or less. Day to day
relative standard deviation for replicate cartridges
should be 25% or less.
14.4.5 A useful performance evaluation step is the use of an
internal standard to track system performance. This
is accomplished by spiking each cartridge, including
blank, sample, and calibration cartridges with approx-
imately 100 nanograms of a compound not generally
present is ambient air (e.g. perfluorotoluene). Spik-
ing is readily accomplished using the procedure outlined
in Section 13.2, using a compressed gas standard. The
integrated ion intensity for this compound helps to
identify problems with a specific sample. In general
the user should calculate the standard deviation of the
internal standard response for a given set of samples
analyzed under identical tuning and calibration conditions.
Any sample giving a value greater than + 2 standard
deviations from the mean (calculated excluding that
particular sample) should be identified as suspect.
Any marked change in internal standard response may
indicate a need for instrument recalibration.
14.5 Method Precision and Recovery
14.5.1 Recovery and precision data for selected volatile organic
compounds are presented in Table 1. These data were
obtained using ambient air, spiked with known amounts
of the compounds in a dynamic mixing system (2).
14.5.2 The data in Table 1 indicate that in general recoveries
better than 75% and precision (relative standard
deviations) of 15-20% can be obtained. However,
selected compounds (e.g. carbon tetrachloride and
-------
T02-27
benzene) will have poorer precision and/or recovery.
The user must check recovery and precision for any
compounds for which quantitative data are needed.
-------
T02-28
References
1. Kebbekus, B. B. and J. W. Bozzelli. Collection and Analysis of
Selected Volatile Organic Compounds in Ambient Air. Proceedings
of Air Pollution Control Association, Paper No. 82-65.2, Air
Pollution Control Association, Pittsburgh, Pennsylvania, 1982.
2. Riggin R. M. and L. E. SIivon. Determination of Volatile Organic
Compounds in Ambient Air Using Carbon Molecular Sieve Adsorbants
Special Report on Contract 68-02-3745 (WA-7), U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina, September,
1983.
3. Riggin, R. M., "Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds in Ambient Air", EPA-600/4-
83-027, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, 1983.
4. Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis-
Occupational Health and Safety", American Society for Testing and
Materials, 1983.
5. Walling, J. F., Berkley, R. E., Swanson, D. H., and Toth, F. J.
rn^lnli ?!r for Gaseous Organic Chemical-Applications to Tenax",
EPA-600/7-54-82-059, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1982.
6. This Methods Compendium - Tenax Method (TO 1).
7. Grob, K., Jr., Grob, G., and Grob, K., "Comprehensive Standardized
?U?ilt:yoJoSt f°r GlaSS CaPillary Columns", J. Chromatog., 156
1-20, 1978. ——
-------
TABLE 1 VOLATILE ORGANIC COMPOUNDS FOR WHICH THE
CMS ADSORPTION METHOD HAS BEEN EVALUATED
Compound
Vinyl Chloride
Acrylonitrile
Vinylidene Chloride
Methylene Chloride
Allyl Chloride
Chloroform
1,2-Dichloroethane
1,1,1-Trichloroethane
Benzene
Carbon Tetrachloride
To!uene
Retention
Time,/ *
Minutes^'
6.3
10.8
10.9
11.3
11.4
13.8
14.5
14.7
15.4
15.5
18.0
Characteristic
Mass Fragment
Used For
Quantification
62
53
96
84
76
83
62
97
78
117
91
Method Performance -Data^
Concentration,
ng/L
17
20
36
28
32
89
37
100
15
86
4.1
Percent
Recovery
74
85
94
93
72
91
85
75
140
55
98
Standard
Deviation
19
18
19
16
19
12
11
9.1
37
2.9
5.4
o
ro
ro
VO
a) GC conditions as follows:
Column - Hewlett Packard, crosslinked methyl silicone,
0.32 mm ID x 50 mm long, thick film, fused silica.
Temperature Program - 70°C for 2 minutes then increased at
8°C/minute to 120°C.
b) From Reference 2. For spiked ambient air.
-------
T02-30
TABLE 2. SUGGESTED PERFORMANCE CRITERIA FOR RELATIVE
ION ABUNDANCES FROM FC-43 MASS CALIBRATION
M/E
% Relative
Abundance
51
69
100
119
131
169
219
264
314
1.8 + 0.5
100
12.0 + 1.5
12.0 + 1.5
35.0 + 3.5
3.0 + 0.4
24.0 + 2.5
3.7 + 0.4
0.25 + 0.1
-------
T02-31
Thermocoupia
Zetex
I mutation
/-Fibarglaa
/ T«p«
mnm
1/4" Nut
t
Radueing
Union
Stainlan
Staal Tuba
1/4" O.D. x 3" Long
Tharmocoupla
Connector
Haatar
Connector
FIGURE 1. DIAGRAM SHOWING CARBON MOLECULAR SIEVE TRAP (CMS) CONSTRUCTION
-------
T02-32
Vtm
Couplings
to Connect
CMS
Cartridge!
(•) Mm Row Control
Rotometer
Vent
Dry
Twt
Pump
Coupling to
Connect CMS
Cartridge
V§1»»
(b| Needle Valve Control
FIGURE 2. TYPICAL SAMPLING SYSTEM CONFIGURATIONS
-------
T02-33
Coupling! for
CMS Cartridge
. Heated 6-Port
Injection Valve
,, Cryogenic Loop («et Figurt SI
Htlium Tank
and Regulator
Flow
Controlltn
Liquid Nitrogen
Helium Purge
From Heated
CMS Trap
60 ml/minute
Helium Purge
From Cooling
CMS Cartridge
MMI
Spectrometer
QC Column
Cooling to -70 C
(b) Velvt - Load Mode
Vent
QC Column
(el Valve - Inject Mode
Cryogenic Trap
Held at Liquid N2
Temperature
Helium Carrier
Flow - 2-3 ml/minute
Cryogenic Trap
Held at 60 C
FIGURE 3. GC/MS ANALYSIS SYSTEM FOR CMS CARTRIDGES
-------
702-3^
PROJECT:,
SITE:
LOCATION:
INSTRUMENT MODEL NO:.
PUMP SERIAL NO:
SAMPLING DATA
SAMPLING DATA SHEET
(One Sample Per Data Sheet)
DATE(S) SAMPLED:
TIME PERIOD SAMPLED:
OPERATOR:
CALIBRATED BY:
Sample Number:_
Start Time:
Stop Time:
Time
1.
2.
3.
4.
N.
Dry Gas
Meter
Reading
Rotameter
Reading
Flow
Rate,*Q
ml/Min
Ambient
Temperature
°C
Barometric
Pressure,
mmHg
Relative
Humidity, X
Comments
Total Volume Data**
Vm * (Final - Initial) Dry Gas Meter Reading, or
Ql + Q2 + Q3---QN
1000 x (Sampling Time in Minutes)
Liters
Liters
* Flowrate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
FIGURE 4. EXAMPLE SAMPLING DATA SHEET
-------
T02-35
oq
30
oo
oc
3O-
OC
1/8" to 1/16" Raduetng Union
1/8" Swagalok Nut and Farrula
Silanizad
Glass
Wool
1/2" Long
60/80 Mash Silanizad Glass Baads
#
e3
oo
>0
°0
oo
Stainlass Staal
Tubing
1/8" O.D. x 0.08" I.D. x 8" Long
FIGURE 5. CRYOGENIC TRAP DESIGN
-------
T02-36
BC
Asymmetry Factor • •—•
AB
ExampU Calculation:
Paak Haight - OE • 100 mm
10% PMk Haight - BO - 10 mm
Paak Width at 10% Paak Haight «• AC • 23 mm
AB -11 mm
BC »12mm
12
Tharafora: Atymmatry Factor - •— «• 1.1
FIGURE 6. PEAK ASYMMETRY CALCULATION
-------
METHOD T03 Revision 1.0
April, 1984
METHOD FOR THE DETERMINATION OF VOLATILE ORGANIC COMPOUNDS
IN AMBIENT AIR USING CRYOGENIC PRECONCENTRATION TECHNIQUES
AND GAS CHROMATOGRAPHY WITH FLAME IONIZATION AND
AND ELECTRON CAPTURE DETECTION
1. Scope
1.1 This document describes a method for the determination of
highly volatile compounds having boiling points in the range
of -10 to 200°C.
1.2 The methodology detailed in this document is currently
employed by numerous laboratories (l-4;8-ll). Modifications
to this methodology should be accompanied by appropriate
documentation of the validity and reliability of these
changes.
2. Applicable Documents
2.1 ASTM Standards
D1356 Definition of Terms Related to Atmospheric Sampling
and Analysis
E 355 Recommended Practice for Gas Chromatography Terms
and Relationships
2.2 Other Documents
Ambient Air Studies (1-4).
U. S. EPA Technical Assistance Document (5).
3. Summary of Method
- 3.1 Ambient air analyses are performed as follows. A collection
trap, as illustrated in Figure 1, is submerged in either
liquid oxygen or argon. Liquid argon is highly recommended
for use because of the safety hazard associated with liquid
-------
T03-2
oxygen. With the sampling valve in the fill position an
air sample is then admitted into the trap by a volume
.measuring apparatus. In the meantime, the column oven is
cooled to a sub-ambient temperature (-50°C). Once sample
collection is completed, the valve is switched so that the
carrier gas sweeps the contents of the trap onto the head of
the cooled GC column. Simultaneously, the liquid cryogen is
removed and the trap is heated to assist the sample transfer
process. The GC column is temperature programmed and the
component peaks eluting from the columns are identified and
quantified using flame ionization and/or electron capture
detection. Alternate detectors (e.g. photoionization) can be
used as appropriate. An automated system incorporating
these various operations as well as the data processing
function has been described in the literature (8,9).
3.2 Due to the complexity of ambient air samples, high resolution
(capillary column) GC techniques are recommended. However,
when highly selective detectors (such as the electron
capture detector) are employed, packed column technology
without cryogenic temperature programming can be effectively
utilized in some cases.
4. Significance
4.1 Volatile organic compounds are emitted into the atmosphere
from a variety of sources including industrial and commercial
facilities, hazardous waste storage facilities, etc. Many
of these compounds are toxic, hence knowledge of the levels
of such materials in the ambient atmosphere is required in
order to determine human health impacts.
4.2 Because these organic species are present at ppb levels or
below, some means of sample preconcentration is necessary in
order to acquire sufficient material for identification and
quantisation. The two primary preconcentration techniques
are cryogenic collection and the use of solid adsorbents.
The method described herein involves the former technique.
-------
T03-3
5. Definitions
Definitions used in this document and any user prepared SOPs should
be consistent with ASTM D1356 (6). All abbreviations and symbols
are defined within this document at the point of use.
6. Interferences/Limitations
6.1 Compounds having similar GC retention times will interfere
in the method. Replacing the flame ionization detector
with more selective detection systems will help to minimize
these interferences. Chlorinated species, in particular,
should be determined using the electron capture detector
to avoid interference from volatile hydrocarbons.
6.2 An important limitation of the technique is the condensation
of moisture in the collection trap. The possibility of
ice plugging the trap and stopping the flow is of concern,
and water subsequently transferred to the capillary column
may also result in flow stoppage and cause deleterious effects
to certain column materials. Use of permaselective Nafion®
tubing in-line before the cryogenic trap avoids this problem;
however, the material must be used with caution because of
possible loses of certain compounds. Another potential
problem is contamination from the Nafion ® tubing. The
user should consult the literature (7-12) for details on the
use of permeation-type driers.
7. Apparatus
7.1 Gas chromatograph/Flame lonization/Electron Capture
Detection System- must be capable of subambient temperature
programming. A recent publication (8) describes an automated
GC system in which the cyrogenic sampling and analysis
features are combined. This system allows simultaneous
flame ionization and electron capture detection.
-------
T03-4
7.2 Six-port sampling valve - modified to accept a sample
collection trap (Figure 1).
7.3 Collection trap - 20 cm x 0.2 cm I.D. stainless steel
tubing packed with 60/80 mesh silanized glass beads and sealed
with glass wool. For the manual system (Section 9.2) the
trap is externally wrapped with 28 gauge (duplex and
fiberglass insulated) type "K" thermocouple wire. This
wire, beaded at one end, is connected to a powerstat
during the heating cycle. A thermocouple is also attached
to the trap as shown in Figure 1.
7.4 Powerstat - for heating trap.
7.5 Temperature readout device - for measuring trap temperature
during heating cycle.
7.6 Glass dewar flask - for holding cryogen.
7.7 Sample volume measuring apparatus - capable of accurately
and precisely measuring a total sample volume up to 500 cc
at sampling rates between 10 and 200 cc/minute. See Section 9.
7.8 Stopwatch.
7.9 Dilution container for standards preparation - glass flasks
or Teflon (Tedlar) bags, .002 inch film thickness (see
Figure 2).
7.10 Liquid microliter syringes - 5-50 yl for injecting liquid
standards into dilution container.
7.11 Volumetric flasks - various sizes, 1-10 ml.
7.12 GC column - Hewlett Packard 50 meter methyl silicone cross-
linked fused silica column (.3 mm I.D., thick film) or
equivalent.
7.13 Mass flow controller - 10-200 mL/minute flow control range.
7.14 Permeation drier - PermaPure* - Model MD-125F, or equivalent.
Alternate designs described in the literature (7-12) may also
be acceptable.
8. Reagents and Materials
8.1 Glass beads - 60/80 mesh, silanized.
-------
T03-5
8.2 Glasswool - silanized.
8.3 Helium - zero grade compressed gas, 99.9999%.
8.4 Hydrogen - zero grade compressed gas, 99.9999%.
8.5 Air - zero grade compressed gas.
8.6 Liquid argon (or liquid oxygen).
8.7 Liquid nitrogen.
8.8 SRM 1805 - benzene in nitrogen standard. Available from the
National Bureau of Standards. Additional such standards will
become available in the future.
8.9 Chemical standards - neat compounds of interest, highest
purity available.
9. Sampling and Analysis Apparatus
Two systems are described below which allow collection of an
accurately known volume of air (100-1000 ml) onto a cryogenically
cooled trap. The first system (Section 9.1) is an automated
device described in the literature (8,9). The second system
(Section 9.2) is a manual device, also described in the liter-
ature (2).
9.1 The automated sampling and analysis system is shown in Figure
3. This system is composed of an automated GC system
(Hewlett Packard Model 5880A, Level 4, or equivalent) and a
sample collection system (Nutech Model 320-01, or equivalent).
The overall system is described in the literature (8).
9.1.1 The electronic console of the sampling unit controls
the mechanical operation of the six-port valve and
cryogenic trapping components as well as the tempera-
tures in each of the three zones (sample trap, transfer
line, and valve).
-------
T03-6
9.1.2 The valve (six-port air activated, Seiscor Model 8
or equivalent) and transfer line are constantly
maintained at 120°C. During sample collection the
trap temperature is maintained at -160 + 5°C by
a flow of liquid nitrogen controlled by a solenoid
valve. A cylindrical 250 with heater, held in
direct contact with the trap, is used to heat the
trap to 120°C in 60 seconds or less during the sample
desorption step. The construction of the sample
trap is described in Section 7.3.
9.1.3 The sample flow is controlled by a pump/mass flow
controller assembly, as shown in Figure 3. A sample
flow of 10-100 mL/minute is generally employed,
depending on the desired sampling period. A total
volume of 100-1000 ml is commonly collected.
9.1.4 In many situations a permaselective drier (e.g.
Nafion®) may be required to remove moisture from
the sample. Such a device is installed at the sample
inlet. Two configurations for such devices are
available. The first configuration is the tube and
shell type in which the sample flow tube is surrounded
by an outer shell through which a countercurrent flow
of clean, dry air is maintained. The dry air stream
must be free from contaminants and its flow rate should
be 3-4 times greater than the sample flow to achieve
effective drying. A second configuration (7)
involves placing a drying agent, e.g. magnesium
carbonate, on the outside of the sample flow tube.
This approach eliminates the need for a source
of clean air in the field. However, contamination
from the drying agent can be a problem.
9.2 The manual sampling consists of the sample volume measuring
apparatus shown in Figure 4 connected to the cryogenic trap/
GC assembly shown in Figure 1. The operation of this
-------
T03-7
assembly is described below.
9.2.1 Pump-Down Position
The purpose of the pump-down mode of operation is to
evacuate the ballast tank in preparation for col-
lecting a sample as illustrated in Figure 4. (While in
this position, helium can also be utilized to back-
flush the sample line, trap, etc. However, this
cleaning procedure is not normally needed during most
sampling operations). The pump used for evacuating
the system should be capable of attaining 200 torr
pressure.
9.2.2 Volume Measuring Position
Once the system has been sufficiently evacuated,
the 4-way ball valve is switched to prepare for sample
collection. The 3-position valve is used to initiate
sample flow while the needle valve controls the rate
of flow.
9.2.3 Sample Volume Calculation
The volume of air that has passed through the col-
lection trap corresponds to a known change in pressure
within the ballast tank (as measured by the Wallace
Tiernan gauge). Knowing the volume, pressure change,
and temperature of the system, the ideal gas law can
be used to calculate the number of moles of air
sampled. On a volume basis, this converts to the
following equation:
760 TA+ 273
-------
T03-8
where
Vs = Volume sampled at 760 mm Hg pressure and
25°C.
AP = Change in pressure within the ballast tank,
mm of Hg.
V = Volume of ballast tank and gauge.
TA = Temperature of ballast tank, °C.
The internal volume of the ballast tank and gauge
can be determined either by H20 displacement or by
injecting calibrated volumes of air into the system
using large volume syringes, etc.
10. Sampling and Analysis Procedure - Manual Device
10.1 This procedure assumes the use of the manual sampling system
described in Section 9.2
10.2 Prior to sample collection, the entire assembly should
be leak-checked. This task is accomplished by sealing
the sampling inlet line, pumping the unit down and placing
the unit in the flow measuring mode of operation. An initial
reading on the absolute pressure gauge is taken and rechecked
after 10 minutes. No apparent change should be detected.
10.3 Preparation for sample collection is carried out by switching
the 6-port valve to the "fill" position and connecting the
heated sample line to the sample source. Meanwhile the
collection trap is heated to 150°C (or other appropriate
temperature). The volume measuring apparatus is pumped-down
and switched to the flow measuring mode. The 3-position
valve is opened and a known volume of sample is then passed
through the heated sample line.and trap to putge the
system.
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T03-9
10.4 After the system purge is completed, the 3-position valve is
closed and the corresponding gauge pressure is recorded.
The collection trap is then immersed into a dewar of liquid
argon (or liquid oxygen) and the 3-position valve is
temporarily opened to draw in a known volume of air, i.e.
a change in pressure corresponds to a specific volume of
air (see Section 9). Liquid nitrogen cannot be used as the
cryogen since it will also condense oxygen from the air.
Liquid oxygen represents a potential fire hazard and should
not be employed unless absolutely necessary.
10.5 After sample collection is completed, the 6-port valve is
switched to the inject position, the dewar is removed and
the trap is heated to 150°C to transfer the sample components
to the head of the GC column which is initially maintained
at -50°C. Temperature programming is initiated to elute
the compounds of interest.
10.6 A GC integrator (or data system if available) is activated
during the injection cycle to provide component identification
and quantitation.
11. Sampling and Analysis Procedure - Automated Device
11.1 This procedure assumes the use of the automated system shown
in Figure 3. The components of this system are discussed
in Section 9.1.
11.2 Prior to initial sample collection the entire assembly should
be leak-checked. This task is completed by sealing the
sample inlet line and noting that the flow indication or the
mass flow controller drops to zero (less than 1 mL/minute).
11.3 The sample trap, valve, and transfer line are heated to
120°C and ambient air is drawn through the apparatus
(^60 mL/minute) for a period of time 5-10 minutes to flush
the system, with the sample valve in the inject position.
During this time the GC column is maintained at 150°C to
condition the column.
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T03-10
11.4 The sample trap is then cooled to -160 + 5°C using a
controlled flow of liquid nitrogen. Once the trap
temperature has stabilized,sample flow through the
trap is initiated by placing the valve in the inject
position and the desired volume of air is collected.
11.5 During the sample collection period the GC column is
stabilized at -50°C to allow for immediate injection
of the sample after collection.
11.6 At the end of the collection period the valve is
immediately placed in the inject position, and the
cryogenic trap is rapidly heated to 120°C to desorb
the components onto GC column. The GC temperature
program and data acquisition are initiated at this
time.
11.7 At the desired time the cryogenic trap is cooled to - 160'C,
the valve is returned to the collect position and the next '
sample collection is initiated (to coincide with the completion
of the GC analysis of the previous sample).
12. Calibration Procedure
Prior to sample analysis, and approximately every 4-6 hours there-
after, a calibration standard must be analyzed, using the identical
procedure employed for ambient air samples (either Section 10 or 11).
This section describes three alternative approaches for preparing
suitable standards.
12.1 Teflon® (on Tedlar®) Bags
12.1.1 The bag (nominal size; 20L) is filled with zero air
and leaked checked. This can be easily accomplished
by placing a moderate weight (text book) on the
inflated bag and leaving overnight. No visible change
in bag volume indicates a good seal. The bag should
also be equipped with a quick-connect fitting for
sample withdrawal and an insertion port for liquid
injections (Figure 2).
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T03-11
12.1.2 Before preparing a standard mixture, the bag is
sequentially filled and evacuated with zero air
(5 times). After the 5th filling, a sample blank
is obtained using the sampling procedure outlined
in Section 10.
12.1.3 In order to prepare a standard mixture, the bag is
filled with a known volume of zero air. This flow
should be measured via a calibrated mass flow
controller or equivalent flow measuring device.
A measured aliquot of each analyte of interest is
injected into the bag through the insertion port
using a microliter syringe. For those compounds
with vapor pressures lower than benzene or for strongly
adsorbed species, the bag should be heated
(60°C) oven) during the entire calibration period.
12.1.4 To withdraw a sample for analysis, the sampling line
is directly connected to the bag. Quick connect
fittings allow this hook-up to be easily accomplished
and also minimizes bag contamination from labora-
tory air. Sample .collection is initiated as described
earlier.
12.2 Glass Flasks
12.2.1 If a glass flask is employed (Figure 2) the exact
volume is determined by weighing the flask before
and after filling with deionized water. The flask
is dried by heating at 200°C.
12.2.2 To prepare a standard, the dried flask is flushed with
zero air until cleaned (i.e. a blank run is made).
An appropriate aliquot of each analyte is injected
using the same procedures as described for preparing
bag standards.
12.2.3 To withdraw a standard for analysis, the GC
sampling line is directly connected to the flask
and a sample obtained. However, because the flask
-------
T03-12
is a rigid container, it will not remain at
atmospheric pressure after sampling has commenced.
In order to prevent room air leakage into the flask,
it is recommended that no more than 10% of the initial
volume be exhausted during the calibration period
(i.e. 200 cc if a 2 liter flask is used).
12.3 Pressurized Gas Cylinders
12.3.1 Pressurized gas cylinders containing selected analytes
at ppb concentrations in air can be prepared or
purchased. A limited number of analytes (e.g.
benzene, propane) are available from NBS.
12.3.2 Speciality gas suppliers will prepare custom gas
mixtures, and will cross reference the analyte
concentrations to an NBS standard for an additional
charge. In general, the user should purchase such
custom mixtures, rather than attempting to prepare
them because of the special high pressure filling
apparatus required. However, the concentrations should
be checked, either by the supplier or the user using
NBS reference materials.
12.3.3 Generally, aluminum cylinders are suitable since most
analytes of potential interest in this method have
been shown to be stable for at least several months
in such cylinders. Regulators constructed of stainless
steel and Teflon® (no silicon or neoprene rubber).
12.3.4 Before use the tank regulator should be flushed by
alternately pressuring with the tank mixture, closing
the tank valve, and venting the regulator contents to
the atmosphere several times.
12.3.5 For calibration a continuous flow of the gas mixture
should be maintained through a glass or Teflon® manifold
from which the calibration standard is drawn. To
generate various calibration concentrations the
-------
T03-13
pressurized gas mixture can be diluted, as desired,
with zero grade air using a dynamic dilution system
(e.g. CSI Model 1700 ).
13. Calibration Strategy
13 1 Vapor phase standards can be prepared with either neat
liquids or diluted liquid mixtures depending upon the
concentration levels desired. It is recommended that benze'ne,
also be included in this preparation scheme so that flame
ionization detector response factors, relative to benzene,
can be determined for the other compounds. The benzene
concentration generated in this fashion should be cross-
checked with an NBS (e.g. SRM 1805) for accuracy determina-
tions.
13 2 Under normal conditions, weekly multipoint calibrations
should be conducted. Each multipoint calibration should
include a blank run and four concentration levels for the
target species. The generated concentrations should bracket
the expected concentration of ambient air samples.
13 3 A plot of nanograms injected versus area using a linear
least squares fit of the calibration data will yield the
following equation:
Y = A + BX
where
Y = quantity of component, nanograms
A = intercept
B = slope (response factor)
If substantial nonlinearity is present in the calibration
curve a quadratic fit of the data can be used:
-------
T03-14
Y = A + BX + CX2
where
C = constant
Alternatively, a, stepwise multilevel calibration scheme
may be used if more convenient for the data system in use.
14. Performance Criteria and Quality Assurance
This section summarizes the quality assurance (QA) measures and
provides guidance concerning performance criteria which should be
achieved within each laboratory.
14.1 Standard Operating Procedures (SOPs)
14.1.1 Each user should generate SOPs describing the
following activities as accomplished in their
laboratories:
1) assembly, calibration and operation of
the sampling system.
2) preparation and handling of calibration
standards.
3) assembly, calibration and operation of the
GC/FID system and
4) all aspects of data recording and processing.
-------
T03-15
14.1.2 SOPs should provide specific stepwise instructions
and should be readily available to, and understood
by, the laboratory personnel conducting the work.
14.2 Method Sensitivity, Precision and Accuracy
14.2.1 System sensitivity (detection limit) for each
component is calculated from the data obtained for
calibration standards. The detection limit is
defined as
DL = A + 3.3S
where
DL = calculated detection limit in
nanograms injected.
A = intercept calculated in Section 13.
S = standard deviation of replicate
determination of the lowest level
standard (at least three deter-
minations are required).
For many compounds detection limits of 1 to 5
nanograms are found using the flame ionization
detection. Lower detection limits can be obtained
for chlorinated hydrocarbons using the electron
capture detector.
14.2.2 A precision of + 5% (relative standard deviation)
can be readily achieved at concentrations 10
times the detection limit. Typical performance
data are included in Table 1.
14.2.3 Method accuracy is estimated to be within + 10%,
based on National Bureau of Standard calibrated
mixtures.
-------
T03-16
REFERENCES
K »nidcen^M^ Spi?er,' C" St1cksel, P., Nepsund, K., Ward, G.,
G flQ offil Lll « K Tm^l Am An +• i ^ 4 M« I II „ _ ^ • ».. .
Analysis oHydcar on
«p6nn and,,a?d J1n?1n"«« "81 Ozone Monitoring
H™ i o ?01^ U:S' Env1ro™ental Protection Agency!
Triangle Park, North Carolina,1982.
2' Ani!i!!!r?'J'* Rasm""en' R" and Holdren, M., "Gas Chromatographic
^i^,^rph.^r.:oUifcthr^:ir5i.^?9?rcai'y
3. J-onneman, H. A., "Ozone and Hydrocarbon Measurements in Recent
UX1Q3 Fl L ll^fln^nftyt ^tiiHTQc" •? T *• r* ^
Pollutant and Its Control ProceedingsrEPA-eOO/^-OOla!1!^?3^
4. Singh, H., "Guidance for the Collection and Use of Ambient
!5e^s D.a.ta. ^ Development of Ozone Control Strategies",
Protection Agency,
5. Rlaaln. R. M , "Technical Assistance Document for Sampling and
ironl^l P^?l^-°mP;UndS innAmbl'ent Air", EPA-600/4-83-027.
6. Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis"
American Society for Testing and Materials, Philadelphia Pen'nsyl'vania,
7. Foulger, B. £. and P. G. Sinamouds, "Drier for Field Use in th»
Determination of Trace Atmospheric Gases", Anal Cnem !^ ^9-1090,
ion , Anal. Chem., submitted, 1984.
9.
10' r°^nT- M;' S'.Rust» R- Smith, and J. Koetz, "Evaluation of
iI-'TOt'n* ?TS f?r Collect^9 Organic Conoids in
Air , Draft Final Report on Contract No. 68-02-3487, 1984.
-------
T03-17
REFERENCES (Continued)
11 Cox R. D. and R. E. Earp,"Determination of Trace Level Organlcs
in Ambient Air by High-Resolution Gas c5romat;?raP^£L»
Simultaneous Photoionization and Flame lomzation Detection ,
Anal. Chem. 54, 2265-2270, 1982.
12 Burns W F., 0. T. Tingy, R. C. Evans and E. H. Bates,
"Problems with a HafloS Membrane Dryer for Chromatographic
Samples", J. Chrom. 269. 1-9, 1983.
-------
T03-18
Sample Voluma
Measuring Apparatus
G.C. Carrier
Gas
Variac
Temperature
Controller
Haatad Sample Line
Sample Source
a. Fill Position
Sample Voluma
Measuring Apparatus
G.C. Carrier
Gas
Variac
Temperature
Controller
Heated Sample Line
* Sample Source
— ——«^ G.C. Column
b. Injection Position
Figure 1. Schematic of Six-Port Valve Used for Sample
Collection.
-------
T03-19
Septum Seal
Claw/Teflon V«l»«
Pinhola Insertion^
Port or Septum \
Injection Port
20 Liter
Teflon Bag
\
Quick Connect
Sampling Port
Figure 2. Dilution Containers for Standard Mixtures
-------
Cryogenic
Sampling
Electronics
Console
Voltage to Solenoid
Liquid N2
Solenoid
Valve
Voltage to
Cartridge
Heaters
ill
Gas Chromatographic System
CD
CO
i
ro
o
FIGURE 3. AUTOMATED SAMPLING AND ANALYSIS
SYSTEM FOR CRYOGENIC TRAPPING
-------
T03-21
Pump
Vant
Shut Off Valva
Halium Tank
Ballast Tank
^} Needle Val<
j ^^- 3 Position Valvt
w
(1) Gas Chromatograph G-Port Valve
(2) (Optional 2nd GC System)
(3) Off
1 2
(a) Volumt Measuring Position
Pump.
Vent
4 Way Ball Valve . Shut Off Valve
u—
Helium Tank
Ballast Tank
(~\ Needle Valve
3 Position Valve
(1 > Gas Chromatograph 6-Port Valve
(2) (Optional 2nd GC System)
(3) Off
1 2
(b) Pump - Down Position
Figure 4. Sample Volume Measuring Apparatus
-------
TABLE
WHICH
CRYOGENIC SAHPLING
Compound
Vinylidene Chloride
Chloroform
1,2-Dichloroethane
Methyl chloroform
Benzene
Trichloroethylene
Tetrachloroethylene
Chlorobenzene
Retention Time,
Minutes'b)
9.26
12.16
12.80
13.00
13.41
14.48
17.37
18.09
Test 1
(4 runs, 200cc
Mean
(Ppb)
144
84
44
63
93
84
69
46
samples)
%RSD
4.4
3.8
3.7
4.5
4.0
3.7
3.7
3.3
Test 2
(8 runs, 200-cc
Mean
(ppb)
6.1
3.5
1.9
2.7
3.9
3.5
2.9
1.9
samples)
%RSD
3.9
5.8
5.1
4.9
5.1
4.1
4.3
3.2
b)GC conditions as follows:
(5cc)
Column - Hewlett Packard, crosslinked methyl silicone, 0.32 mm ID x 50 m long, thick
i i i HI y I U*>6Q 5111 CQ •
Temperature Program - 50°C for 2 minutes, then increased at 8°C/minute to 150°C.
I
ho
r-o
-------
METHOD T04 Revision 1.0
April, 1984
METHOD FOR THE DETERMINATION OF ORGANOCHLORINE PESTICIDES
AND POLYCHLORINATED BIPHENYLS IN AMBIENT AIR
1. Scope
1.1 This document describes a method for determination of a
variety of organochlorine pesticides and polychlorinated
biphenyls (PCBs) in ambient air. Generally, detection
limits of >1 ng/m3 are achievable using a 24-hour sampling
period.
1.2 Specific compounds for which the method has been employed
are listed in Table 1. Several references are available
which provide further details on the development and
application of the method. The sample cleanup and analysis
methods are identical to those described in U. S. EPA Method
608. That method is included as Appendix A of this methods
compendium.
2. Applicable Documents
2.1 ASTM Standards
D1356 Definition of Terms Related to
Atmospheric Sampling and Analysis (7).
2.2 Other Documents
Ambient Air Studies (1-3)
U. S. EPA Technical Assistance Document (4).
U. S. EPA Method 608 (5). See Appendix A of methods
compendium.
3. Summary of Method
3.1 A modified high volume sampler consisting of a glass
fiber filter with a polyurethane foam (PUF) backup
absorbent cartridge is used to sample ambient air at
a rate of ^200-280 L/minute.
-------
T04-2
3.2 The filter and PUF cartridge are placed in clean, sealed
containers and returned to the laboratory for analysis.
The PCBs and pesticides are recovered by Soxhlet extraction
with 5% ether in hexane.
3.3 The extracts are reduced in volume using Kuderna-Danish (K-D)
concentration techniques and subjected to column chroma-
tographic cleanup.
3.4 The extracts are analyzed for pesticides and PCBs using gas
chromatography with electron capture detection (GC-ECD), as
described in U. S. EPA Method 608 (5).
4. Significance
4.1 Pesticides, particularly organochlorine pesticides, are widely
used in both rural and urban areas for a variety of applications
PCBs are less widely used, due to extensive restrictions placed
on their manufacture. However, human exposure to PCBs
continues to be a problem because of their presence in
various electrical products.
4.2 Many pesticides and PCBs exhibit bioaccumulative, chronic health
effects and hence monitoring ambient air for such compounds
is of great importance.
4.3 The relatively low levels of such compounds in the environment
requires the use of high volume sampling techniques to
acquire sufficient sample for analysis. However, the volatility
of these compounds prevents efficient collection on filter
media. Consequently, this method utilizes both a filter and
a PUF backup cartridge which provides for efficient collection
of most organochlorine pesticides, PCBs, and many other organics
within the same volatility range.
5. Definitions
Definitions used in this document and any user-prepared SOPs
should be consistent with ASTM D1356 (7). All abbreviations
-------
T04-3
and symbols are defined within this document at the point of
use.
6. Interferences
6.1 The use of column chromatographic cleanup and selective GC
detection (GC-ECD) minimizes the risk of interference from
extraneous organic compounds. However, the fact that PCBs
as well as certain organochlorine pesticides (e.g. toxaphenfe
and chlordane) are complex mixtures of individual compounds
can cause difficulty in accurately quantifying a particular
formulation in a multiple component mixture.
6.2 Contamination of glassware and sampling apparatus with traces
of pesticides or PCBs can be a major source of error in the
method, particularly when sampling near high level sources
(e.g. dumpsites, waste processing plants, etc.) careful attention
to cleaning and handling procedures is required in all steps
of the sampling and analysis to minimize this source of error.
7. Apparatus
7.1 Hi-Vol Sampler with PUF cartridge - available from General
Metal Works (Model PS-1). See Figure 1.
7.2 Sampling Head to contain glass cartridge with PUF plug - available
from General Metal Works. See Figure 2.
7.3 Calibration orifice - available from General Metal Works.
7.4 Manometer - to use with calibration orifice.
7.5 Soxhlet extraction system - including Soxhlet extractors
(500 and 250 ml), heating mantels, variable voltage trans-
formers, and cooling water source - for extraction of PUF
cartridges before and after sampling. Also for extraction of
filter samples.
7.6 Vacuum oven connected to water aspirator - for drying
extracted PUF cartridges.
7.7 Gas chromatograph with electron capture detector - (consult
U. S. EPA Method 608 for specifications).
-------
T04-4
7.8 Forceps - to handle quartz fiber filter samples.
7.9 Die - to cut PUF plugs..
7.10 Various items for extract preparation, cleanup, and analysis
consult U. S. EPA Method 608 for detailed listing.
7.11 Chromatography column - 2 mm I.D. x 15 cm long - for alumina
cleanup.
8. Reagent and Materials
8.1 Polyurethane foam - 3 inch thick sheet stock, polyether
type used in furniture upholstering. Density 0.022 g/cm3.
8.2 Polyester gloves - for handling PUF cartridges and filters
8.3 Filters, quartz fiber - Pallflex 2500 QAST , or equivalent.
8.4 Wool felt filter - 4.9 mg/cm2 and 0.6 mm thick. To fit
sample head for collection efficiency studies. Pre-
extracted with 5% diethyl ether in hexane.
8.5 Hexane - Pesticide or distilled in glass grade.
8.6 Diethyl ether - preserved with 2% ethanol - distilled in
glass grade, or equivalent.
8.7 Acetone - Pesticide or distilled in glass grade.
8.8 Glass container for PUF cartridges.
8.9 Glass petri dish - for shipment of filters to and from the
laboratory.
8.10 Ice chest - to store samples at ^0°C after collection.
8.11 Various materials needed for extract preparation; cleanup,
and analysis - consult U. S. EPA Method 608 for details
(Appendix A of this compendium).
8.12 Alumina - activity grade IV. 100/200 mesh
9. Assembly and Calibration of Sampling Apparatus
9.1 Description of Sampling Apparatus
9.1.1 The entire sampling system is diagrammed in Figure 1.
This sampler was developed by Syracuse University
-------
T04-5
Research Corporation (SURC) under a U. S. EPA
contract (6) and further modified by Southwest
Research Institute and the U. S. EPA. A unit
specifically designed for this method is now commer-
cially available (Model PS-1 - General Metal Works,
Inc., Village of Cleves, Ohio). The method
writeup assumes the use of the commercial device,
although the earlier modified device is also con-
sidered acceptable.
9.1.2 The sampling module (Figure 2) consists of a glass
sampling cartridge and an air-tight metal cartridge
holder. The PDF plug is retained in the glass
sampling cartridge.
9.2 Calibration of Sampling System
9.2.1 The airflow through the sampling system is monitored
by a venturi/Manehelic assembly, as shown in Figure 1.
A multipoint calibration of the venturi/mag-
nehelic assembly must be conducted every six months
using an audit calibration orifice, as described in
the U. S. EPA High Volume Sampling Method (8). A
single point calibration must be performed before
and after each sample collection, using the procedure
described below.
9.2.2 Prior to calibration a "dummy" PUF cartridge and
filter are placed in the sampling head and the sampling
motor is activated. The flow control valve is
fully opened and the voltage variator is adjusted
so that a sample flow rate corresponding to ^110% of
the desired flow rate is indicated on the magnehelic
(based on the previously obtained multipoint cali-
bration curve). The motor is allowed to warmup
for ^10 minutes and then the flow control valve is
adjusted to achieve the desired flow rate. The
ambient temperature and barometric pres:jre s ould
-------
T04-6
be recorded on an appropriate data sheet (e.g. Figure 3),
9.2.3 The calibration orifice is then placed on the sampling
head and a manometer is attached to the tap on the
calibration orifice. The sampler is momentarily
turned off to set the zero level of the manometer.
The sampler is then switched on and the manometer
reading is recorded, once a stable reading is
achieved. The sampler is then shut off.
9.2.4 The calibration curve for the orifice is used to
calculate sample flow from the data obtained in
9.2.3, and the calibration curve for the venturi/
magnehelic assembly is used to calculate sample
flow from the data obtained in 9.2.2. The calibra-
tion data should be recorded on an appropriate
data sheet (e.g. Figure 3). If the two values do
not agree within 10% the sampler should be inspected
for damage, flow blockage, etc. If no obvious problems
are found the sampler should be recalibrated (multi-
point) according to the U. S. EPA High Volume
Sampling procedure (8).
9.2.5 A multipoint calibration of the calibration orifice,
against a primary standard, should be obtained
annually.
10. Preparation of Sampling (PUF) Cartridges
10.1 The PUF adsorbent is a polyether-type polyurethane foam
(density No. 3014 or 0.0225 g/cm3). This type of foam
is used for furniture upholstery. It is white and yellows
on exposure to light.
10.2 The PUF inserts are 6.0 cm diameter cylindrical plugs cut
from 3 inch sheet stock and should fit with slight com-
pression in the glass cartridge, supported by the wire
-------
T04-7
screen. See Figure 2. During cutting the die is rotated
at high speed (e.g. in a drill press) and continuously
lubricated with water.
10.3 For initial cleanup the PUT plug is placed in a Soxhlet
extractor and extracted with acetone for 14-24 hours at
approximately 4 cycles per hour. When cartridges are
reused, 5% diethyl ether in n-hexane can be used as the
cleanup solvent.
10.4 The extracted PUF is placed in a vacuum oven connected
to a water aspirator and dried at room temperature for
approximately 2-4 hours (until no solvent odor is detected).
10.5 The PUF is placed into the glass sampling cartridge using
polyester gloves. The module is wrapped with hexane
rinsed aluminum foil, placed in a labeled container
and tightly sealed.
10.6 Other adsorbents may be suitable for this method as indicated
in the various references (1-3). If such materials are
employed the user must define appropriate preparation
procedures based on the information contained in these
references.
10.7 At least one assembled cartridge from each batch must be
analyzed, as a laboratory blank, using the procedures
described in Section 12, before the batch is considered
acceptable for field use. A blank levelof <10 ng/plug
for single compounds is considered to be acceptable. For
multiple component mixtures (e.g. Arochlors) the blank level
should be <100 ng/plug.
11. Sampling
11.1 After the sampling system has been assembled and calibrated
as described in Section 9 it can be used to collect air
samples as described below.
11.2 The samples should be located in an unobstructed area, at
least two meters from any obstacle to air flow. The
exhaust hose should be stretched out in the downwind
-------
urao^iAua pun XSoioDa Jeded papAo9J
T04-8
direction to prevent recycling of air.
11.3 A clean sampling cartridge and quartz fiber filter are removed
from sealed transport containers and placed in the sampling
.head using forceps and gloved hands. The head is tightly sealed
into the sampling system. The aluminum foil wrapping is
placed back in the sealed container for later use.
11.4 The zero reading of the Magnehelic is checked. Ambient
temperature, barometric pressure, elapsed time meter setting,
sampler serial number, filter number and PUT cartridge number
are recorded. A suitable data sheet is shown in Figure 4.
11.5 The voltage variator and flow control valve are placed at the
settings used in 9.2.3 and the power switch is turned on.
The elapsed time meter is activated and the start time recorded.
The flow (Magnehelic setting) is adjusted, if necessary using
the flow control valve.
11.6 The Magnehelic reading is recorded every six hours during
the sampling period. The calibration curve (Section 9.2.7) is
used to calculate the flow rate. Ambient temperature and
barometric pressure are recorded at the beginning and end of
the sampling period.
11.7 At the end of the desired sampling period the power is turned
off and the filter and PUF cartridges are wrapped with the
original aluminum foil and placed in sealed, labeled containers
for transport back to the laboratory.
11.8 The Magnehelic calibration is checked using the calibration
orifice as described in Section 9.2.4. If the calibration
deviates by more than 10% from the initial reading the flow data
for that sample must be marked as suspect and the sampler
should be inspected and/or removed from service.
11.9 At least one field blank will be returned to the laboratory
with each group of samples. A field blank is treated exactly
as a sample except that no air is drawn through the cartridge.
-------
T04-9
11.10 Samples are stored at ^20°C in an ice chest until receipt at
the analytical laboratory, at which time they are stored
refrigerated at 4°C.
12. Sample Preparation and Analysis
12.1 Sample Preparation
12.1.1 All samples should be extracted within 1 week after
collection.
12.1.2 PUF cartridges are removed from the sealed con-
container using gloved hands, the aluminum foil
wrapping is removed, and the cartridges are placed
into a 500-mL Soxhlet extraction. The cartridges are
extracted for 14-24 hours at ^4 cycles/hour with 5%
diethyl ether in hexane. Extracted cartridges can be
dried and reused following the handling procedures
in Section 10. The quartz filter can be placed in
the extractor with the PUF cartridges. However, if
separate analysis is desired then one can proceed with
12.1.3.
12.1.3 If separate analysis is desired, quartz filters are
placed in a 250-mL Soxhlet extractor and extracted
for 14-24 hours with 5% diethyl ether in hexane.
12.1.4 The extracts are concentrated to 10 ml final
volume using 500-mL Kuderna-Danish concentrators
as described in EPA Method 608 (5), using a hot water
bath. The concentrated extracts are stored refrigerated
in sealed 4-dram vials having teflon-lined screw-caps
until analyzed or subjected to cleanup.
12.2 Sample Cleanup
12.2.1 If only organochlorine pesticides and PCBs are sought,
an alumina cleanup procedure reported in the literature
is appropriate (1). Prior to cleanup the sample
-------
T04-10
extract is carefully reduced to 1 ml using a gentle
steam of clean nitrogen.
12.2.2 A glass chromatographic column (2 mm ID x 15 cm long)
is packed with alumina, activity grade IV and rinsed
with ^20 ml of n-hexane. The concentrated sample
extract (from 12.2.1) is placed on the column and
eluted with 10 ml of n-hexane at a rate of 0.5
mL/minute. The eluate volume is adjusted to
exactly 10 ml and analyzed as described in 12.3.
12.2.3 If other pesticides are sought, alternate cleanup
procedures (e.g. Florisil) may be required. Method
608 (5) identifies appropriate cleanup procedures.
12.3 Sample Analysis
12.3.1 Sample analysis is performed using 6C/ECD as
described in EPA Method 608 (5). The user must
consult this method for detailed analytical procedures.
12.3.2 GC retention times and conditions are identified
in Table 1 for the compounds of interest.
13. GC Calibration
Appropriate calibration procedures are identified in EPA Method
608 (5).
14. Calculations
14.1 The total sample volume Ofo ) is calculated from the
periodic flow readings (Magnehelic) taken in Section
11.6 using the following equation.
N 1000
where
-------
T04-11
2
V = Total sample volume (m ).
Q-i, QO-..QM = Flow rates determl'ned at the
beginning, end, and intermediate points during
sampling (L/minute).
N » Number of data points averaged.
T = Elapsed sampling time (minutes).
14.2 The volume of air sampled can be converted to standard
conditions (760 mm Hg pressure and 25°C) using the following
equation:
A 298
v = v X — X **°
5 m 760 273+tA
where
V = Total sample volume at 25°C and 760 mm Hg
pressure (m ) 3
V = Total sample flow under ambient conditions (m )
m / H \
P. = Ambient pressure (mm Hg)
t, = Ambient temperature (°C)
A
14.3 The concentration of compound in the sample is calculated
using the following equation:
A x Vc
CA =
V.xvs
where
C. « Concentration of analyte in the sample,
yg/m
A = Calculated amount of material injected onto
the chromatograph based on calibration curve
for injected standards (nanograms)
V. = Volume of extract injected (yL).
-------
T04-12
VE = Final volume of extract (ml).
Vs = Total volume of air samples corrected to
standard conditions (m3).
14. Performance Criteria and Quality Assurance
This section summarizes the quality assurance (QA) measures and
provides guidance concerning performance criteria which should
be achieved within each laboratory.
14.1 Standard Operating Procedures (SOPs)
14.1.1 Users should generate SOPs describing the follow-
ing activities as accomplished in their laboratory:
1) assembly, calibration and operation of the
sampling system, 2) preparation, purification, storage
and handling of sampling cartridges, 3) assembly,
calibration and operation of the GC/ECD system, and
4) all aspects of data recording and processing.
14.1.2 SOPs should provide specific stepwise instructions
and should be readily available to, and understood
by, the laboratory personnel conducting the work.
14.2 Process, Field, and Solvent Blanks
14.2.1 One PUF cartridge and filter from each batch of
approximately twenty should be analyzed, without
shipment to the field, for the compounds of
interest to serve as a process blank.
14.2.2 During each sampling episode at least one PUF
cartridge and filter should be shipped to the field
and returned, without drawing air through the sampler,
to serve as a field blank.
14.2.3 During the analysis of each batch of samples at
least one solvent process blank (all steps conducted
but no PUF cartridge or filter included) should be
-------
T04-13
carried through the procedure and analyzed.
14.2.4 Blank levels should not exceed -v.10 ng/sample for
single components or ^100 ng/sample for multiple
component mixtures (e.g. PCBs).
14.3 Collection Efficiency and Spike Recovery
14.3.1 Before using the method for sample analysis each
laboratory must determine their collection
efficiency for the components of interest.
14.3.2 The glass fiber filter in the sampler is replaced
with a hexane-extracted wool felt filter (weight
14.9 mg/cm2, 0.6 mm thick). The filter is spiked
with microgram amounts of the compounds of interest
by dropwise addition of hexane solutions of the
compounds. The solvent is allowed to evaporate
and filter is placed into the sampling system for
immediate use.
14.3.3 The sampling system, including a clean PUF cartridge,
is activated and set at the desired sampling flow
rate. The sample flow is monitored for 24 hours.
14.3.4 The filter and PUF cartridge are then removed and
analyzed as described in Section 12.
14.3.5 A second sample, unspiked is collected over the
same time period to account for any background
levels of components in the ambient air matrix.
14.3.6 A third PUF cartridge is spiked with the same amounts
of the compounds used in 14.3. 2 and extracted to
determine analytical recovery.
14.3.7 In general analytical recoveries and collection
efficiencies of 75% are considered to be acceptable
method performance.
-------
T04-14
14.3.8 Replicate (at least triplicate) determinations of
collection efficiency should be made. Relative
standard deviations for these replicate determinations
of + 15% or less is considered acceptable performance.
14.3.9 Blind spiked samples should be included with sample
sets periodically, as a check on analytical per-
formance.
14.4 Method Precision and Accuracy
Typical method recovery data are shown in Table 1. Re-
coveries for the various chlorobiphenyls illustrate the
fact that all components of an Arochlor mixture will not
be retained to the same extent. Recoveries for tetrachloro-
biphenyls and above are generally greater than 85% but
di- and trichloro homologs may not be recovered quantitatively.
-------
T04-15
REFERENCES
°B»se:rde £»;£&• 'i^™^ «^ AI ,
Anal. Chem. 49, 1668-1672, 1977.
'
Park, NC, 1980
Park, NC, 1983.
5- assr^u s
EPA-600/4-82-057! U. S. Environmental Protection Agency,
Cincinnati, OH, 1982.
"
Association, Durham, NC, 1970
7.
1983.
8 Reference Method for the Determination of Suspended Particulates
in the Atmosphere (High Volume Method). Federal Register,
Sept. 14, 1972 or 40CFR50 Appendix B.
-------
T04-16
TABLE 1. SELECTED COMPONENTS DETERMINED USING HI-VOL/PUF SAMPLING PROCEDURE
24-Hour Sampling Efflciency(b)
Compound
Aldrin
4,4'-DDE
4,4'-DDT
Chlordane
Chlorobiphenyls
4,4' Di-
2,4,5 Tri-
2, 4', 5 Tri-
2, 2', 5, 5' Tetra-
2, 2', 4, 5, 5' Penta-
2, 2', 4, 4', 5, 5' Hexa
GC Retention
Time, Minutest3 )
2.4
5.1
9.4
(c)
--
—
—
—
—
--
Air
Concentration
ng/m3
0.3-3.0
0.6-6.0
1.8-18
15-150
2.0-20
0.2-2.0
0.2-2.0
0.2-2.0
0.2-2.0
0.2-2.0
%
Recovery
28
89
83
73
62
36
86
94
92
86
(a) Data from U.S. EPA Method 608. Conditions are as follows;
Stationary Phase - 1.5% SP2250/1.95% SP-2401 on
Supelcoport (100/120 mesh) packed in 1.8 mm long x
4 mm ID glass column.
Carrier - 5/95 methane/Argon at 60 mL/Minute
Column Temperature - 160°C except for PCBs which are
determined at 200°C.
(b) From Reference 2.
(c) Multiple component formulation. See U.S. EPA Method 608.
-------
T04-17
Sampling
Head
(See Figure 2)
Magnehelic
Gauge
0-100 in.
Exhaust
Duct
(6 in. x 10 ft)
Voltage Variator
Elapsed Time Meter
FIGURE 1. HIGH VOLUME AIR SAMPLER. AVAILABLE
FROM GENERAL METAL WORKS (MODEL PS-1)
-------
Lower Canister
Filter Holder
With Support
Screen
4" Diameter Filter
Glass Cartridge
and Puf Plug
Silicone Rubber
Gaskets
Filter Retaining Ring-
-H
O
-c*
I
00
Silicone -
Rubber
Gasket
FIGURE 2. SAMPLING HEAD
-------
Performed by_
Date/nine
Calibration Orifice
Manometer S/M
S/M
Ambient Teaperature_
Bar.Press.
Hg
Sampler
S/N
Varlac
Setting V
Timer OK?
Yes/No
Calibration Orifice
Data
Manometer,
In. H20
Flow Rate,
son /min(')
Sampler
Venturl Data
Magnetic lie,
In. H20
Flow Rate
scm/mln W
S Difference Between
Calibration and Sample
Venturl Flow Rates
Comments
o
-e-
(a) From Calibration Tables for Calibration Orifice or Venturl Tube
(b) From Calibration Tables for Venturl Tube 1n each Hi-Vol unit.
Date check by
Date
FIGURE 3. TYPICAL CALIBRATION SHEET FOR HIGH VOLUME SAMPLER
-------
Simirior
S/N
l>) ROHKO-
Sampling Location
ID
MV •vidwie* of Mini
NOT
F«t« lv'
Mrmff wtthM
PUFC.H
No.
Mnplor aml/o
Vcrisc
S*nin«
r •bnormi
Sun. hr CD
Mint in umptor
Cloch Tim*
Slop, hr CD
OCMrition. PU
M« EI.P.M
: onridgt cond
Stin. mm
ition or handlir
S*mpl*t Timar
Step, mm
if, tte.
Min ELpwd
Vcnturi RMdmgr Tim>/M«gn«nlic in. H2
1
2
3
4
Ambi*n1
T«mp«r»tur«. "C
S»n
Stop
B«fomvtric
S»n
Stop
— 1
o
.Cr
1
ro
o
D>» ChKkrd By.
FIGURE 4. TYPICAL SAMPLING DATA FORM FOR HIGH VOLUME PESTICIDE/PCB SAMPLER
-------
METHOD T05 Revision 1.0
April, 1984
METHOD FOR THE DETERMINATION OF ALDEHYDES AND KETONES IN AMBIENT AIR
USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC)
1. Scope
1.1 This document describes a method for determination of
individual aldehydes and ketones in ambient air. With
careful attention to reagent purity and other factors
the method can detect most monofunctional aldehydes and
ketones at the 1-2 ppbv level.
1.2 Specific compounds for which the method has been employed
are listed in Table 1. Several studies have used the
same basic method, with minor procedural differences,
for analysis of ambient air (1-3).
2. Applicable Documents
2.1 ASTM Standards:
D 1356 Definitions of Terms Related to Atmospheric
Sampling and Analysis (s)
2.2 Other Documents
Ambient air studies (1-3).
U.S. EPA Technical Assistance Document (4)
3. Summary of Method
3.1 Ambient air is drawn through a midget impinger containing 10 mL
of 2I\[ HC1/0.05% 2,4-dinitrophenylhydrazine (DNPH reagent)
and 10 mL of isooctane. Aldehydes and ketones readily
form stable 2,4-dinitrophenylhydrazones (DNPH derivatives).
-------
T05-2
3.2 The impinger solution is placed in a screw-capped vial having
a teflon-lined cap and returned to the laboratory for analysis,
The DNPH derivatives are recovered by removing the isooctane
layer, extracting the aqueous layer with 10 ml of 70/30
hexane/methylene chloride, and combining the organic
layers.
3.3 The combined organic layers are evaporated to dryness under
a steam of nitrogen and the residue dissolved in methanol.
3.4 The DNPH derivatives are determined using reversed phase
HPLC with an ultraviolet (UV) adsorption detector operated
at 370 nm.
4. Significance
4.1 Aldehydes and ketones are emitted into the atmosphere from
chemical operations and various combustion sources. In
addition, several of these compounds (e.g. formaldehyde and
acetaldehyde) are produced by photochemical degradation
of other organic compounds. Many of these compounds are
acutely toxic and/or carcinogenic, thus requiring their
determination in ambient air in order to assess human
health impacts.
4.2 Conventional methods for aldehydes and ketones have generally
employed colorimetric techniques wherein only one or two
compounds are detected, or the sum of numerous compounds
is determined. The method described herein provides a
means for specifically determining a wide variety of aldehydes
and ketones at typical ambient concentrations.
5. Definitions
Definitions used in this document and any user prepared SOPs
should be consistent with ASTM D1356(5). All abbreviations and
symbols are defined within this document at the point of use.
-------
T05-3
6. Interferences
6 1 The only significant interferences in the method are certain
isomeric aldehydes or ketones which may be unresolved by
the HPLC system. Such interferences can often be overcome by
altering the separation conditions (e.g. using alternate
HPLC columns or mobile phase compositions).
6.2 Formaldehyde contamination of the DNPH reagent is a
frequently encountered problem. The reagent must be
prepared within 48 hours before use and must be stored in
an uncontaminated environment before and after sampling to
minimize blank problems. Acetone contamination is
apparently unavoidable. Consequently, the method cannot be
used to accurately measure acetone levels except in highly
contaminated environments.
7. Apparatus
7 1 Isocratic HPLC system-consisting of high pressure
pump, injection valve, Zorbax CDS column (25 cm x 4.6 mm ID),
variable wavelength UV detector, and data system or
stripchart recorded. See Figure 3.
7 2 Sampling system-capable of accurately and precisely
sampling 100-1000 mL/minute of ambient air. See Figure 1.
7.3 Stopwatch
7.4 Friction top metal can e.g. one-gallon (paint can) - to hold
DNPH reagent and samples
7.5 Thermometer - to record ambient temperature.
7.6 Barometer (optional)
7.7 Analytical balance - 0.1 mg sensitivity
7.8 Reciprocating shaker
7.9 Midget impingers - jet inlet type - 25 mL volume.
7.10 Ice bath - for cooling impingers during sampling.
-------
T05-4
7.11 Nitrogen evaporator with heating block - for concentrating
samples
7.12 Suction filtration apparatus - for filtering HPLC
mobile phase.
7.13 Volumetric flasks - 100 mL and 500 ml.
7.14 Pipettes - various sizes, 1-10 ml.
7.15 Helium purge line (optional) - for degassing HPLC
mobile phase.
7.16 Erlenmeyer flask, 1-liter - for preparing HPLC mobile
phase.
7.17 Graduated cylinder, 1 liter - for preparing HPLC mobile
phase.
7.18 Microliter syringe, 10-25 uL - for HPLC injector.
8. Reagents and Materials
8.1 Bottles, 10 oz. glass, with teflon-lined screw cap - for
storing DNPH reagent.
8.2 Vials, 50 mL, with teflon-lined screw cap - for holding
samples and extracts.
8.3 Disposable pipettes and bulbs.
8.4 Granular charcoal.
8.5 Methanol, hexane, methylene chloride, isooctane - distilled
in glass or pesticide grade.
8.6 2,4-Dinitrophenylhydrazine - highest purity available
(20% moisture).
8.7 Nitrogen, compressed gas cylinder -99.99% purity for
sample evaporation.
8.8 Polyester filters, 0.22 ym - Nuclepore or equiv.
8.9 DNPH derivatives of the components of interest -
synthesized from DNPH and neat aldehydes according
to reference (7). Recrystallized from ethanol before
use.
-------
T05-5
9. Preparation of DNPH Reagent
9.1 Each batch of DNPH reagent should be prepared and purified
within 48 hours of sampling, according to the procedure
described in this section.
9.2 Two hundred and fifty milligrams of solid 2,4-dinitro-
phenylhydrazine and 90 ml of concentrated hydrochloric
acid are placed into a 500 ml volumetric flask and the
flask is filled to the mark with reagent water. The
flask is then inverted several times or sonified until all of
the solid material has dissolved.
9.3 Approximately 400 ml of the DNPH reagent is placed in a
16 ounce glass screw-capped bottle having a teflon-lined
cap. Approximately 50 ml of a 70/30 (V/V) hexane/methylene
chloride mixture is added to the bottle and the capped
bottle is shaken for 15 minutes on a reciprocating shaker.
The organic layer is then removed and discarded by decanting
as much as possible and using a disposable pipette to
remove the remaining organic layer.
9.4 The DNPH reagent is extracted two more times as described
in 9.3. The bottle is then tightly capped, sealed with
teflon tape, and placed in a friction top can (paint can)
containing a 1-2 inch layer of granulated charcoal. The
bottle is kept in the sealed can prior to use.
9.5 A portion of the DNPH reagent is analyzed using the
procedure described in Section 11 prior to use in order to
ensure that adequate background levels are maintained.
10. Sampling
10.1 The sampling apparatus is assembled and should be similar to
that shown in Figure 1. EPA Method 6 uses essentially the same
sampling system (8). All glassware (e.g. impingers, sampling
bottles, etc.) must be thoroughly rinsed with methanol and oven
dried before use.
-------
T05-6
10.2 Prior to sample collection the entire assembly (including
empty sample impingers) is installed and the flow rate
checked at a value near the desired rate. In general
flow rates of 100-1000 mL/minute are useful. Flow rates
greater than *1000 mL/minute should not be used because
impinger collection efficiency may decrease. Generally
calibration is accomplished using a soap bubble flow
meter or calibrated wet test meter connected to the flow
exit, assuming the entire system is sealed. ASTM Method
D3686 describes an appropriate calibration scheme not
requiring a sealed flow system downstream of the pump.
10.3 Ideally a dry gas meter is included in the system to'record
total flow. If a dry gas meter is not available the operator
must measure and record the sampling flow rate at the
beginning and end of the sampling period to determine
sample volume. If the sampling period exceeds two hours
the flow rate should be measured at intermediate points
during the sampling period. Ideally a rotameter should be
included to allow observation of the flow rate without
interruption of the sampling process.
10.4 To collect an air sample two clean midget impingers are
loaded with 10 ml of purified DNPH reagent and 10 mL of
isooctane. The impingers are connected in series to
the sampling system and sample flow is started. The follow-
ing parameters are recorded on the data sheet (see Figure 3
for an example): date, sampling location, time, ambient
temperature, barometric pressure (if available), relative
humidity (if available), dry gas meter reading (if appro-
priate), flow rate, rotometer setting, DNPH reagent batch
number, and dry gas meter and pump identification numbers.
10.5 The sampler is allowed to operate for the desired period,
with periodic recording of the variables listed above.
The total flow should not exceed «u80 liters. The operator
must ensure that at least 2-3 ml of isooctane remains in
the first impinger at the end of the sampling interval
(i.e. for high ambient temperatures lower sampling volumes
may be required).
-------
T05-7
10.6 At the end of the sampling period the parameters listed
in 10.4 are recorded and the sample flow is stopped. If
a dry gas meter is not used the flow rate must be checked
at the end of the sampling interval. If the flow rate
at the beginning and end of the sampling period differ
by more than 15% the sample should be marked as suspect.
10.7 Immediately after sampling the impingers are removed from
the sampling system. The contents of the first impinger
are emptied into a clean 50 ml glass vial having a teflon^
lined screw cap. The first impinger is then rinsed with
the contents of the second (backup) impinger and the rinse
solution is added to the vial. The vial is then capped,
sealed with teflon tape and placed in a friction top can
containing 1-2 inches of granular charcoal. The samples
are stored in the can, refrigerated until analysis.
10.8 If a dry gas meter or equivalent total flow indicator is
not used the average sample flow rate must be calculated
according to the following equation:
Q Q1 +Q2 •••• QN
A N
where
Q. = Average flow rate in mL/minute.
0,, Q2,...QN= Flow rates determined at the
beginning, end, and intermediate
points during sampling.
N = Number of points averaged.
10.9 The total flow is then calculated using the following
equation:
(T2-T,)I1A
" m ~
1000
Vm = Total volume sampled in liters at measured
temperature and pressure
T2 = Stop time
T1 » Start time (T2-T] given in minutes)
-------
T05-8
11. Sample Analysis
11.1 Sample Preparation
11.1.1 The samples are returned to the laboratory in
50 ml screw-capped glass vials. To recover the
DNPH derivatives the following procedure is em-
ployed.
11.1.2 The vials are shaken in a horizontal position on
a reciprocating shaker for 10 minutes. The vials
are then removed from the shaker and the isooctane
layer is removed and placed in a second clean 50 ml
screw-capped glass vial using a disposable pipette.
11.1.3 The remaining aqueous layer is extracted with 10 ml
of 70/30 (V/V) hexane/methylene chloride in the
same manner as described in 11.1.2. The organic
layer is removed and combined with the isooctane
extract.
11.1.4 The combined organic extracts are then concentrated
to dryness at 40°C under a steam of pure nitrogen.
When the sample just reaches dryness the vial is
removed from the nitrogen stream and a measured
volume (2-5 ml) of methanol is added to the vial.
The vial is tightly capped and stored refrigerated
until analysis.
11.2 HPLC Analysis
11.2.1 The instrument is assembled and calibrated as described
in Section 12. Prior to each analysis the detector
baseline is checked to ensure stable operation.
11.2.2 A 5-25 ML aliquot of the sample, dissolved in
methanol.is drawn into a clean HPLC injection syringe.
The sample injection loop is loaded and an injection
is made. The data system, if available, is activated
simultaneously with the injection and the point of
injection is marked on the stripchart recorder.
-------
T05-9
11.2.3 After approximately one minute, the injection valve
is returned to "load" position and the syringe and
valve are flushed with methanol in preparation for
the next sample analysis.
11.2.4 After elution of the last component of interest the
acquisition is terminated and the component concen-
trations are calculated as described in Section 13.
11.2.5 After a stable baseline is achieved the system can
be used for further sample analyses as described above.
11.2.6 If the concentration of a component exceeds the linear
range of the instrument the sample should be diluted
with methanol, or a smaller volume can be injected
onto the HPLC.
12. HPLC Assembly and Calibration
12.1 The HPLC system is assembled as shown in Figure 3. The
typical chromatographic performance and operating para-
meters are shown in Figure 4.
12.2 Mobile phase is prepared by mixing 800 mL of methanol and
200 mL of reagent water. This mixture is filtered through
a 0.22 vm polyester membrane filter in an all glass and
teflon suction filtration apparatus. The filtered mobile
phase is degassed by purging with helium gas for 10-15
minutes (* 100 mL/minute) or by heating to ^60°C for 5-10
minutes in an Erlenmeyer flask covered with a watch glass. A
constant back pressure restrictor (* 50 psi) or short length
(6-12 inches) of 0.01 inch I.D. teflon tubing should be
placed after the detector to further eliminate mobile phase
outgassing.
12.3 The mobile phase is placed in the HPLC solvent reservoir and
the pump flow is set at 1 mL/minute and allowed to pump
for 20-30 minutes prior to the first analysis. The detector
is switched on at least 30 minutes prior to the first
analysis and the detector output is displayed on a stripchart
recorder or similar output device at a sensitivity of .008
-------
T05-10
absorbance units full scale (AUFS). Once a stable baseline
is achieved the system is ready for calibration.
12.4 Calibration standards are prepared in methanol from the
solid DNPH derivatives. Individual stock solutions of
*• 100 mg/L are prepared by dissolving 10 mg of the solid
derivative in 100 mL of methanol. These individual solutions
are used to prepare calibration standards containing all of
the derivatives of interest at concentrations of 0.1 - 10 mg/L
which spans the concentration of interest for most ambient
air work.
12.5 All calibration runs are performed as described for sample
analyses in Section 11. Before initial use the operator
should inject a series of calibration standards (at least
three levels) spanning the concentration range of interest.
Using the UV detector, a linear response range of approximately
0.1 to 10 mg/L should be achieved, for * 10 VL injection
volumes. Linear response is indicated where a correlation
coefficient of a least 0.999 for a linear least squares
fit of the data (concentration versus area response) is
obtained.
12.6 Once linear response has been documented an intermediate
concentration standard near the anticipated levels for each
component, but at least 10 times the detection limit, should
be chosen for daily calibration. The response for the various
DNPH components should be within 10% day to day. If greater
variability is observed more frequent calibration may be
required to ensure that valid results are obtained.
12.7 The response for each component in the daily calibration
standard is used to calculate a response factor according
to the following equation:
Cc X VI
RFc = £ 1
Rc
-------
T05-11
where
RF = response factor for the component of
interest in nanograms injected/response
unit (usually area counts).
C = concentration of component in the daily
calibration standard (mg/L).
V = volume of calibration standard injected (uL)
R = response for component of interest in
calibration standard (area counts).
13. Calculations
13.1 The volume of air sampled is often reported uncorrected for
atmospheric conditions (i.e. under ambient conditions).
However, the value can be adjusted to standard conditions
(25°C and 760 mm pressure) using the following equation:
P. 298
Vsx Vm x -2- x
760 273 + T.
where
Vs = total sample volume at 25°C and 760 mm Hg
pressure (liters).
Vm = total sample volume under ambient conditions
(liters). Calculated in 10.9 or from dry gas
meter reading.
PA * ambient pressure (nmHg).
T/\ = ambient temperature (°C).
13.2 The concentration of each aldehyde (as the DNPH derivative is
calculated for each sample using the following equation:
-------
T05-12
Wd = RFc X Rd X ~
VI
where
Wrf = total quantity of derivative in the sample
RFc = response factor calculated in 12.7
Rd = response for component in sample extract
(area counts or other response units).
VE = final volume of sample extract (mL).
Vj = volume of extract injected onto the HPLC
system (yL).
13.3 The concentration of aldehyde in the original sample is
calculated from the following equation:
W. MW.
C = X -A- X 1000
Hn(°r Vs ) MWd
where
CA = concentration of aldehyde in the original
sample (ng/L).
1|n or Vs are as specified in Section 13.1.
MWA and MWd are the molecular weights (g/mole) of
the aldehyde and its corresponding DNPH derivative,
respectively.
13.4 The aldehyde concentrations can be converted to ppbv using
the following equation:
24.4
C.(ppbv) = C.(ng/L) X
MWA
where
CA(ng/L) is calculated using Vs.
-------
T05-13
14. Performance Criteria and Quality Assurance
This section summarizes the quality assurance (QA) measures and
provides guidance concerning performance criteria which should
be achieved within each laboratory.
14.1 Standard Operating Procedures (SOPs).
14.1.1 Each user should generate SOPs describing the
following activities as accomplished in their
laboratory: 1) assembly, calibration and operation
of the sampling system, 2) preparation, purification,
storage and handling of DNPH reagent and samples, 3)
assembly, calibration and operation of the HPLC
system, and 4) all aspects of data recording and
processing.
14.1.2 SOPs should provide specific stepwise instructions
and should be readily available to, and understood
by, the laboratory personnel conducting the work.
14.2 HPLC System Performance
14.2.1 The general appearance of the HPLC chromatograph
should be similar to that shown in Figure 4.
14.2.2 The HPLC system efficiency and peak asymmetry
factor should be determined in the following manner.
A solution of the formaldehyde DNPH derivative cor-
responding to at least 20 times the detection
limit should be injected with the recorder chart
sensitivity and speed set to yield a peak
approximately 75% of full scale and 1 cm wide at
half height. The peak asymmetry factor is determined
as shown in Figure 5, and should be between
0.8 and 1.8.
-------
T05-14
14.2.3 HPLC system efficiency is calculated according to
the following equation:
where
N = column efficiency, theoretical plates
tr= retention time of components (seconds)
V/i/2 = width of component peak at half height
(seconds)
A column efficiency of >5,000 should be obtained.
14.2.4 Precision of response for replicate HPLC injections
should be ± 10% or less, day to day, for calibration
standards. Precision of retention times should be
± 2%, on a given day.
14.3 Process Blanks
14.3.1 Prior to use a 10 mL aliquot of each batch of DNPH
reagent should be analyzed as described in Section
11. In general,formaldehyde levels equivalent to
>5 ng/L in a 60 liter sample should be achieved
and other aldehyde levels should be <1 ng/L.
14.3.2 At least one field blank should be shipped and
analyzed with each group of samples. The field
blank is treated identically to the samples except
that no air is drawn through the reagent. The
same performance criteria described in 14.3.1
should be met for process blanks.
-------
T05-15
14.4 Method Precision and Accuracy
14.4.1 Analysis of replicate samples indicates a pre-
cision of + 15-20% relative standard deviation
can be readily achieved. Each laboratory should
collect parallel samples periodically (at least one
for each batch of samples) to document their
precision in conducting the method.
14.4.2 Precision for replicate HPLC injections should
be i 10% or better, day to day, for calibration ,
standards.
14.4.3 Method accuracy is difficult to assess because of
the difficulty in generating accurate gaseous
standards. Literature results indicate (1-3)
recoveries of 75% or greater are achieved for a
broad range of aldehydes. Each laboratory should
periodically collect field samples wherein the
impinger solution is spiked with a known quantity
of the compound of interest, prepared as a dilute
methanol solution. Formaldehyde cannot be spiked
in this manner and therefore a solution of the DNPH
derivative should be used for spiking purposes.
14.4.4 Before initial use of the method each laboratory
should generate triplicate spiked samples at a minimum
of three concentration levels, bracketing the
range of interest for each compound. Triplicate
nonspiked samples must also be processed. Recover-
ies of >70 ± 20%.and blank levels of <5 ng/L for
formaldehyde and 1 ng/L for the other compounds
(assuming a 60 liter air sample) should be achieved.
-------
T05-16
References
/iiHoh^ • '*u 1- K;' and Atkinson» R-« "Measurements of
A's^c^laJer^-SO1^^!^^1"' "^ Al> Po11' <""•
(2) Grosjean, D. and Fung K., "Collection Efficiencies of Cartridges
and Micro-Impingers for Sampling of Aldehydes in Air as 2,J- §
Dinitrophenylhydrazones", Anal. Chem. 54, 1221-1224, 1982
(3) ?mM«naVD''' "Formalde!!yde and Other Carbonyls in Los Angeles
Ambient Air", Environ. Sci. Techno!. ]6, 254-262, 1982.
IJ?lc,!eR'*M;t '!'Te^hn1cal Assistance Document for Sampling and
S Envi Organic Compounds in Ambient Air", EPA-600/4-83-027
(5) Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis"
SCle0r ^^ ^ »™«' ^ "^ '
Snirp' °r Au' H°Jdr?n' M" W" Lyon' T' F" Rl'99in. R- M. . and
Spicer, C W ., Turbine Engine Exhaust Hydrocarbon Analysis-Interim
Report on Task 1 and 2", Report on Contract No. F-08635-82-C-OT3"
^983 En9ineering and Services Center, Tyndall AFB, Florida, '
(7) Shiner, R Fuson, R and Curtin, D. , "The Systematic Identification
' John Wile^ and Sons, Inc., 5th ed. , New
(8) "Method 6 Determination of S02 Emissions from Stationary Sources",
Federal Register, Vol. 42., No. 160, August 1977.
-------
T05-17
TABLE .1. ALDEHYDES AND KETCHES FOR WHICH THE METHOD HAS BEEN EVALUATED
Mnlecular Weight
^™^~ « _ _
Typical
Relative
Retention
Compound
Formaldehyde
Acetaldehyde
Acrolein
Propanal
Acetone
Crotonaldehyde
Isobutyraldehyde
Methyl Ethyl Ketone
Benzaldehyde
Pentanal
o-Tolualdehyde
m-Tolualdehyde
p-Tolualdehyde
Hexanal
Derivative
210
224
236
238
238
250
252
252
286
266
300
300
300
280
Compound.
30
44
56
58
58
70
72
72
106
86
120
120
120
100
1.0
1.3
1.6
1.7
l.g(b)
2.3
2.4
2.8
3.2
3.7
4.8
5.1
5.3
5.7
(b) Acetone background levels in the reagent prevent its determination
in most cases.
-------
Silica Gel
Rotometer
Dry
Test
Vent
Pump
Valve
Sample Impinger
(DNPH Reagent) /
Inlet
O
en
i
00
FIGURE 1. TYPICAL SAMPLING SYSTEM
-------
T05-19
SAMPLING DATA SHEET
(One Sarole Per Data Sheet)
PROJECT:.
SITE:
DATE(S) SAMPLED:.
LOCATION:
TIME PERIOD SAMPLED:.
OPERATOR:
INSTRUMENT MODEL NO:.
PUMP SERIAL NO:
SAMPLING DATA
CALIBRATED BY:
Sample Number:.
Start Time:
Stop Time:
Time
1
2
3.
4
N.
Dry Gas
Meter
Reading
Rotameter
Reading
Flow
Rate,*Q
ml/Min
Ambient
Temperature
°C
Barometric
Pressure,
mmHg
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
Ql + Q? + Q3---QN 1
= _' R x 1000 x (Sampling Time in Minutes)
Liters
Liters
* Flowrate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
FIGURE 2. EXAMPLE SAMPLING DATA SHEET
-------
INJECTION
VALVE
COLUMN
MOBILE
PHASE
RESERVOIR
1 VARIABLE
WAVELENGTH
UV
DETECTOR
• •
DATA
SYSTEM
o
en
ro
o
STRIPCHART
RECORDER
FIGURE 3. TYPICAL HPLC SYSTEM
-------
o
en
i
ro
2 0
40
60
FIGURE 4. TYPICAL HPLC CHROMATOGRAM
Column - Zorbax ODS, 250 x 4.6 mm
Mobile Phase - 80/20 Methanol/^O
Flow Rate - 1 ml/Minutc
Detector - UV at 370 nm
-------
T05-22
Asymmttry Factor » ?£.
AB
Example Calculation:
Paak Height - OE - 100 mm
10% Peak Height - 80 - 10 mm
Paak Width at 10% Paak Height » AC - 23 mm
AB- 11 mm
BC *12mm
Tharafora: Aiymmatry Factor - ~ » 1.1
FIGURE 8. PEAK ASYMMETRY CALCULATION
-------
APPENDIX A— EPA METHOD 608
Environmental Monitoring and
Research and Development
Test Method
Organochlorine Pesticides
and PCBs — Method 608
1. Scope and Application
1.1 This method covers the
determination of certain organochlorine
pesticides and PCBs. The following
parameters can be determined by this
method:
Parameter
Aldrin
a-BHC
0-BHC
d-BHC
y-BHC
Chlordane
4, 4 '-ODD
4,4 '-DDE
4,4 '-DDT
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Heptachlor
Heptachlor epoxide
Toxaphene
PCB-1016
PCB-1221
PCB-1232
PCB-1242
PCB-1248
PCS- 12 54
PCB-1260
STORET No.
39330
39337
39338
34259
39340
39350
39310
39320
39300
39380
34361
34356
34351
39390
34366
39410
39420
39400
34671
39488
39492
39496
39500
39504
39508
CAS No.
309-00-2
319-84-6
319-85-7
319-86-8
58-89-9
57-74-9
72-54-8
72-55-9
50-29-3
60-57-1
959-98-8
33212-65-9"
1031-07-8
72-20-8
7421-93-4
76-44-8
1024-57-3
8001-35-2
12674-11-2
11104-28-2
11141-16-5
53469-21-9
12672-29-6
11097-69-1
11096-82-5
1 2 This is a gas chromatographic
(GO method applicable to the determi-
nation of the compounds listed above
in municipal and industrial discharges
M provided under 40 CFR 1 36. 1 .
When this method is used to analyze
unfamiliar samples for any or all of the
compounds above, compound idenf.fi-
cations should be supported by at least
one additional qualitative technique.
This method describes analytical
conditions for a second gas
chromatographic column that can be
used to confirm measurements made
with the primary column. Method 625
provides gas ch~™tc^rapWrnass
spectrometer (GC/MS) condjt.ons
appropriate for the qualitative and
608-1
1982
-------
quantitative confirmation of results for
all of the parameters listed above,
using the extract produced by this
method.
1.3 The method detection limit (MDL,
defined in Section 14.1)<1> for each
parameter is listed in Table 1. The MDL
for a specific wastewater may differ
from those listed, depending upon the
nature of interferences in the sample
matrix.
1.4 The sample extraction and
concentration steps in this method are
essentially the same as in methods
606, 609, 611 and 612. Thus, a
single sample may be extracted to
measure the parameters included in the
scope of each of these methods. When
cleanup is required, the concentration
levels must be high enough to permit
selection of aliquots as necessary to
.apply appropriate cleanup procedures.
The analyst is allowed the latitude to
select gas chromatographic conditions
appropriate for the simultaneous
measurement of combinations of these
parameters.
1.5 Any modification of this method,
beyond those expressly permitted,
shall be considered as major
modifications subject to application
and approval of alternate test
procedures under 40 CFR 1 36 4 and
136.5.
1.6 This method is restricted to use
by or under the supervision of analysts
experienced in the use of gas chroma-
tography and in the interpretation of
gas chromatograms. Each analyst must
demonstrate the ability to generate
acceptable results with this method
using the procedure described in
Section 8.2.
2. Summary of Method
2.1 A measured volume of sample,
approximately one-liter, is solvent
extracted with methylene chloride
using a separatory funnel. The
methylene chloride extract is dried and
exchanged to hexane, during
concentration to a final volume of 10
ml or less. Gas chromatographic
conditions are described which permit
the separation and measurement of the
parameters in the extract by electron
capture GCI2>.
2.2 The method provides a Florisil
column procedure and elemental sulfur
removal procedure to aid in the
elimination of interferences that may
be encountered.
3. Interferences
3.1 Method interferences may be
caused by contaminants in solvents,
reagents, glassware, and other sample
processing hardware that lead to
discrete artifacts and/or elevated
baselines in gas chromatograms. All of
these materials must be routinely
demonstrated to be free from inter-
ferences under the conditions of the
analysis by running laboratory reagent
blanks as described in Section 8.5.
3.1.1 Glassware must be scrupulously
cleanedi3i. Clean all glassware as soon
as possible after use by rinsing with the
last solvent used in it. This should be
followed by detergent washing with
hot water, and rinses with tap water
and distilled water. It should then be
drained dry and heated in a muffle
furnace at 400 °C for 1 5 to 30
minutes. Some thermally stable
materials, such as PCBs, may not be
eliminated by this treatment. Solvent
rinses with acetone and pesticide
quality hexane may be substituted for
the muffle furnace heating. Thorough
rinsing with such solvents usually
elmmates PCB interference. Volumetric
ware should not be heated in a muffle
furnace. After drying and cooling,
glassware should be sealed and stored
in a clean environment to prevent any
accumulation of dust or other
contaminants. Store inverted or capped
with aluminum foil.
3.1.2 The use of high purity reagents
and solvents helps to minimize
interference problems. Purification of
solvents by distillation in all-glass
systems may be required.
3,2 Interferences by phthalate esters
can pose a major problem in pesticide
analysis when using the elution capture
detector. These compounds generally
appear in the chromatogram as large
eluting peaks, especially in the 1 5 and
50% fractions from Florisil. Common
flexible plastics contain varying
amounts of phthalates. These phtha-
lates are easily extracted or leached
from such materials during laboratory
operations. Cross contamination of
clean glassware routinely occurs when
plastics are handled during extraction
steps, especially when solvent wetted
surfaces are handled. Interferences
from phthalates can best be minimized
by avoiding the use of plastics in the
laboratory. Exhaustive cleanup of
reagents and glassware may be
required to eliminate background
phthalate contamination!4.5i. Tne
interferences from phthalate esters can
be avoided by using a microcoulometric
or electrolytic conductivity detector.
3.3 Matrix interferences may be
caused by contaminants that are
coextracted from the sample. The
extent of matrix interferences will vary
considerably from source to source,
depending upon the nature and
diversity of the industrial complex or
municipality being sampled. The
cleanup procedures in Section 1 1 can
be used to overcome many of these
interferences, but unique samples may
require additional cleanup approaches
to achieve the MDL listed in Table 1.
4. Safety
4.1 The toxicity or carcinogenicity of
each reagent used in this method has
not been precisely defined; however,
each chemical compound should be
treated as a potential health hazard.
From this viewpoint, exposure to these
chemicals must be reduced to the
lowest possible level by whatever
means available. The laboratory is
responsible for maintaining a current
awareness file of OSHA regulations
regarding the safe handling of the
chemicals specified in this method. A
reference file of material data handling
sheets should also be made available to
all personnel involved in the chemical
analysis. Additional references to
laboratory safety are available and
have been identified'6-8) for tne
information of the analyst.
4.2 The following parameters
covered by this method have been
tentatively classified as known or
suspected, human or mammalian
carcinogens: 4,4'-DDT,4,4'-ODD, the
BHCs, and the PCBs. Primary
standards of these toxic compounds
should be prepared in a hood.
5. Apparatus and Materials
5.1 Sampling equipment, for discrete
or composite sampling.
5.7.7 Grab sample bottle —Amber
glass, one-liter or one-quart volume,
fitted with screw caps lined with
Teflon. Foil may be substituted for
Teflon if the sample is not corrosive. If
amber bottles are not available, protect
samples from light. The container must
be washed, rinsed with acetone or
methylene chloride, and dried before
use to minimize contamination.
5.1.2 Automatic sampler (optional)-
Must incorporate glass sample
containers for the collection of a mini-
mum of 250 mL. Sample containers
must be kept refrigerated at 4 °C and
protected from light during compositing.
If the sampler uses a peristaltic pump,
a minimum length of compressible
608-2
July 1982
-------
silicone rubber tubing may be used.
Before use, however, the compressible
tubing should be thoroughly rinsed
with methanol, followed by repeated
rinsings with distilled water to minimize
the potential for contamination of the
sample. An integrating flow meter is
required to collect flow proportional
composites.
5.2 Glassware (All specifications are
suggested. Catalog numbers are
included for illustration only).
5.2.1 Separatory funnel-2000-mL,
with Teflon stopcock.
5.2.2 Drying column-Chroma-
tographic column approximately 400
mm long x 1 9 mm ID, with coarse frit.
5.2.3 Chromatographic column —
Pyrex, 400 mm long x 22 mm ID,
with coarse fritted plate and Teflon
stopcock (Kontes K-42054 or
equivalent).
5.2.4 Concentrator tube, Kuderna-
Danish— 10-mL, graduated (Kontes K-
570050-1 025 or equivalent). Calibra-
tion must be checked at the volumes
employed in the test. Ground glass
stopper is used to prevent evaporation
of extracts.
5.2.5 Evaporative flask, Kuderna-
Danish-500-mL (Kontes K-570001-
0500 or equivalent). Attach to
concentrator tube with springs.
5.2.6 Snyder column, Kuderna-
Danish-three-ball macro (Kontes
K-503000-01 21 or equivalent).
5.2.7 Vials-Amber glass, 10-to
1 5-mL capacity, with Teflon-lined
screw cap.
5.3 Boiling chips-approximately
10/40 mesh. Heat to 400 °C for 30
minutes or Soxhlet extract with
methylene chloride.
5.4 Water bath —Heated, with
concentric ring cover, capable of
temperature control ( ± 2 °C). The bath
should be used in a hood.
5.5 Balance —Analytical, capable of
accurately weighing 0.0001 g.
5.6 Gas chromatograph —An
analytical system complete with gas
chromatograph suitable for on-column
injection and all required accessories
including syringes, analytical columns,
gases, detector, and strip-chart
recorder. A data system is
recommended for measuring peak
areas.
5.6.7 Column 1-1.8 m long x 4
mm ID glass, packed with 1.5%
SP-2250/1.95% SP-2401 on
Supelcoport (10011 20 mesh) or
equivalent. Column 1 was used to
develop the method performance
statements in Section 14. Guidelines
for the use of alternate column
packings are provided in Section 12.1.
5.6.2 Column 2-1.8 m long x 4
mm ID glass, packed with 3% OV-1 on
Supelcoport (10011 20 mesh) or
equivalent:
5.6.3 Detector-Electron capture.
This detector has proven effective in
the analysis of wastewaters for the
parameters listed in the scope, and
was used to develop the method
performance statements in Section 14.
Guidelines for the use of alternate
detectors are provided in Section 12.1.
6. Reagents
6.1 Reagent water-Reagent water is
defined as a water in which an inter-
ferent is not observed at1 the MDL of
each parameter of interest.
6.2 Sodium hydroxide solution (10
N)-(ACS). Dissolve 40g NaOH in
reagent water and dilute to 1 00 ml.
6.3 Sodium thiosulfate-(ACS).
Granular.
6.4 Sulfuric acid solution (1 + 1 )-
(ACS). Slowly, add 50 ml H2S04 (sp.
gr. 1.84) to 50 ml of reagent water.
6.5 Acetone, hexane, isooctane
(2,2,4-trimethylpentane), methylene
chloride-Pesticide quality or
equivalent.
6.6 Ethyl ether- Pesticide quality or
equivalent, redistilled in glass if
necessary.
6.6.7 Must be free of peroxides as
indicated by EM Laboratories Quant
test strips (Available from Scientific
Products Co., Cat. No. P1 1 26-8, and
others suppliers.)
6.6.2 Procedures recommended for
removal of peroxides are provided with
the test strips. After cleanup, 20 ml
ethyl alcohol preservative must be
added to each liter of ether.
6.7 Sodium sulfate-(ACS) Granular,
anhydrous. Purify by heating at 400 °C
for 4 hours in a shallow tray.
6.8 Florisil-PR grade (60/1 00
mesh); purchase activated at 1 250 °F
and store in dark in glass containers
with glass stoppers or foil-lined screw
caps. Before use, activate each batch
at least 16 hours at 1 30 °C in a foil
covered glass container.
6.9 Mercury —Triple distilled.
6.10 Copper powder-Activated.
6.11 Stock standard solutions (1.00
^ig/nD-Stock standard solutions can
be prepared from pure standard
materials or purchased as certified
solutions.
6.77.7 Prepare stock standard
solutions by accurately weighing about
0.01 00 grams of pure material.
Dissolve the material in isooctane,
dilute to volume in a 10-mL volumetric
flask. Larger volumes can be used at
the convenience of the analyst. If
compound purity is certified at 96% or
greater, the weight can be used
without correction to calculate the
concentration of the stock standard.
Commercially prepared stock standards
can be used at any concentration if
they are certified by the manufacturer
or by an independent source,
6.77.2 Transfer the stock standard
solutions into Teflon-sealed screw-cap
bottles. Store at 4 °C and protect from
light. Stock standard solutions should
be checked frequently for signs of
degradation or evaporation, especially
just prior to preparing calibration
standards from them. Quality control
check standards that can be used to
determine the accuracy of calibration
standards will be available from the
U.S. Environmental Protection Agency,
Environmental Monitoring and Support
Laboratory, Cincinnati, Ohio 45268.
6.77.3 Stock standard solutions
must be replaced after six months, or
sooner if comparison with check
standards indicate a problem.
7. Calibration
7.1 Establish gas Chromatographic
operating parameters which produce
retention times equivalent to those
indicated in Table 1. The gas
Chromatographic system may be
calibrated using the external standard
technique (Section 7.2) or the internal
standard technique (Section 7.3).
7.2 External standard calibration
procedure:
7.2. 7 Prepare calibration standards
at a minimum of three concentration
levels for each parameter of interest by
adding volumes of one or more stock
standards to a volumetric flask and
diluting to volume with isooctane. One
of the external standards should be at a
concentration near, but above, the
MDL and the other concentrations
should correspond to the expected
range of concentrations found in real
samples or should define the working
range of the detector.
608-3
July 1982
-------
7.2.2 Using injections of 2 to 5 ^L of
each calibration standard, tabulate
peak height or area responses against
the mass injected. The results can be
used to prepare a calibration curve for
each compound. Alternatively, if the
ratio of response to amount injected
(calibration factor) is a constant over
the working range «10% relative
standard deviation, RSD), linearity
through the origin can be assumed and
the average ratio or calibration factor
can be used in place of a calibration
curve.
7.2,3 The working calibration curve
or calibration factor must be verified on
each working day by the measurement
of one or more calibration standards. If
the response for any parameter varies
from the predicted response by more
than ± 10%, the test must be repeated
using a fresh calibration standard.
Alternatively, a new calibration curve
o.r calibration factor must be prepared
for that compound.
7.3 Internal standard calibration
procedure. To use this approach, the
analyst must select one or more
internal standards that are similar in
analytical behavior to the compounds
of interest. The analyst must further
demonstrate that the measurement of
the internal standard is not affected by
method or matrix interferences.
Because of these limitations, no
internal standard can be suggested that
is applicable to all samples.
7.3. 1 Prepare calibration standards
at a minimum of three concentration
levels for each parameter of interest by
adding volumes of one or more stock
standards to a volumetric flask. To
each calibration standard, add a known
constant amount of one or more
internal standards, and dilute to volume
with isooctane. One of the standards
should be at a concentration near, but
above, the MDL and the other concen-
trations should correspond to the
expected range of concentrations
found in real samples or should define
the working range of the detector.
7.3.2 Using injections of 2 to 5 pi of
each calibration standard, tabulate
peak height or area responses against
concentration for each compound and
internal standard, and calculate
response factors (RF) for each
compound using equation 1 .
Eq. 1. RF = (ASC1S)/!A,SCS)
where:
As = Response for the parameter to
be measured.
AI8 = Response for the internal
standard.
Cls = Concentration of the internal
standard, (^g/L).
Cs = Concentration of the param-
eter to be measured, (jig/L).
If the RF value over the working
range is a constant «1 0% RSD), the
RF can be assumed to be invariant and
the average RF can be used for
calculations. Alternatively, the results
can be used to plot a calibration curve
of response ratios, AS/AIS, vs. RF.
7.3.3 The working calibration curve
or RF must be verified on each working
day by the measurement of one or
more calibration standards. If the
response for any parameter varies from
the predicted response by more than
± 1 0%, the test must be repeated
using a fresh calibration standard.
Alternatively, a new calibration curve
must be prepared for that compound.
7.4 The cleanup procedure in Section
11 utilizes Florisil chromatography.
Florisil from different batches or
sources may vary in absorptive
capacity. To standardize the amount of
Florisil which is used, the use of lauric
acid valued is suggested. The refer-
enced procedure determines the
adsorption from hexane solution of
lauric acid (mg) per gram Florisil. The
amount of Florisil to be used for each
column is calculated by dividing this
factor into 1 10 and multiplying by 20
g.
7.5 Before using any cleanup
procedure, the analyst must process a
series of calibration standards through
the procedure to validate elution
patterns and the absence of interfer-
ences from the reagents.
8. Quality Control
8.1 Each laboratory that uses this
method is required to operate a formal
quality control program. The minimum
requirements of this program consist of
an initial demonstration of laboratory
capability and the analysis of spiked
samples as a continuing check on
performance. The laboratory is required
to maintain performance records to
define the quality of data that is
generated. Ongoing performance
checks must be compared with
established performance criteria to
determine if the results of analyses are
within accuracy and precision limits
expected of the method.
S. 1.1 Before performing any analyses,
the analyst must demonstrate the
ability to generate acceptable accuracy
and precision with this method. This
ability is established as described in
Section 8.2.
8.1.2 In recognition of the rapid
advances that are occurring in chroma-
tography, the analyst is permitted
certain options to improve the separa-
tions or lower the cost of measurements.
Each time such modifications are made
to the method, the analyst is required
to repeat the procedure in Section 8.2.
8.1.3 The laboratory must spike and
analyze a minimum of 1 0% of all
samples to monitor continuing labora-
tory performance. This procedure is
described in Section 8.4.
8.2 To establish the ability to
generate acceptable accuracy and pre-
cision, the analyst must perform the
following operations.
8.2.1 Select a representative spike
concentration for each compound to be
measured. Using stock standards,
prepare a quality control check sample
concentrate in acetone 1 000 times
more concentrated than the selected
concentrations. Quality control check
sample concentrates, appropriate for
use with this method, will be available
from the U.S. Environmental Protection
Agency, Environmental Monitoring and
Support Laboratory, Cincinnati, Ohio
45268.
8.2.2 Using a pipet, add 1.00 ml of
the check sample concentrate to each
of a minimum of four 1000-mL aliquots
of reagent water. A representative
wastewater may be used in place of
the reagent water, but one or more
additional aliquots must be analyzed to
determine background levels, and the
spike level must exceed twice the
background level for the test to be
valid. Analyze the aliquots according to
the method beginning in Section 10.
8.2.3 Calculate the average percent
recovery, (R), and the standard devia-
tion of the percent recovery (s), for the
results. Wastewater background cor-
rections must be made before R and s
calculations are performed.
8.2.4 Using Table 2, note the
average recovery (X) and standard
deviation (p) expected for each method
parameter, Compare these to the cal-
culated values for R and s. If s > 2p or
|X-R > 2p, review potential problem
areas and repeat the test.
8.2.S The U.S. Environmental Pro-
tection Agency plans to establish
performance criteria for R and s based
upon the results of interlaboratory
testing. When they become available,
these criteria must be met before any
samples may be analyzed.
8.3 The analyst must calculate
method performance criteria and define
6Q8-4
July 1982
-------
the performance of the laboratory for
each spike concentration and
parameter being measured.
8.3.1 Calculate upper and lower
control limits for method performance:
Upper Control Limit (UCL) = R + 3s
Lower Control Limit (LCD = R - 3s
where R and s are calculated as in
Section 8.2.3. The UCL and LCL can
be used to construct control charts'101
that are useful in observing trends in
performance. The control limits above
be replaced by method performance
criteria as they become available from
the U.S. Environmental Protection
Agency.
8.3.2 The laboratory must develop
and maintain separate accuracy
statements of laboratory performance
for wastewater samples. An accuracy
statement for the method is defined as
R ± s. The accuracy statement should
be developed by the analysis of four
aliquots of wastewater as described in
Section 8.2.2, followed by the calcula-
tion of R and s. Alternately, the analyst
may use four wastewater data points
gathered through the requirement for
continuing quality control in Section
8.4. The accuracy statements should
be updated regularly! 10>.
8.4. The laboratory is required to
collect a portion of their samples in
duplicate to monitor spike recoveries.
The frequency of spiked sample analysis
must be at least 10% of all samples or
one sample per month, whichever is
greater. One aliquot of the sample must
be spiked and analyzed as described in
Section 8.2. If the recovery for a
particular parameter does not fall
within the control limits for method
performance, the results reported for
that parameter in all samples processed
as part of the same set must be quali-
fied as described in Section 1 3.5. The
laboratory should monitor the frequency
of data so qualified to ensure that it
remains at or below 5%.
8.5 Before processing any samples,
the analyst should demonstrate through
the analysis of a one-liter aliquot of
reagent water,^that all glassware and
reagent interferences are under control.
Each time a set of samples is extracted
or there is a change in reagents, a
laboratory reagent blank should be
processed as a safeguard against
laboratory contamination.
8.6 It is recommended that the
laboratory adopt additional quality
assurance practices for use with this
method. The specific practices that are
most productive depend upon the
needs of the laboratory and the nature
of the samples. Field duplicates may be
analyzed to monitor the precision of
the sampling technique. When doubt
exists over the identification of a peak
on the chromatogram, confirmatory
techniques such as gas chromatography
with a dissimilar column, specific
element detector, or mass spectrometer
must be used. Whenever possible, the
laboratory should perform analysis of
standard reference materials and parti-
cipate in relevant performance
evaluation studies.
9. Sample Collection,
Preservation, and Handling
9.1 Grab samples must be collected
in glass containers. Conventional
sampling practices!1 n should be
followed, except that the bottle must
not be prewashed with sample before
collection. Composite samples should
be collected in refrigerated glass
containers in accordance with the
requirements of the program. Automatic
sampling equipment must be as free as
possible of Tygon tubing and other
potential sources of contamination.
9.2 The samples must be iced or
refrigerated at 4 °C from the time of
collection until extraction. If the
samples will not be extracted within
72 hours of collection, the sample
should be adjusted to a pH range of
5.0 to 9.0 with sodium hydroxide or
sulfuric acid. Record the volume of acid
or base used. If aldrin is to be
determined, add sodium thiosulfate
when residual chlorine is present. U.S.
Environmental Protection Agency
methods 330.4 and 330.5 may be
used to measure chlorine residual'12|.
Field test kits are available for this
purpose.
9.3 All samples must be extracted
within 7 days and completely analyzed
within 40 days of extraction^'.
10. Sample Extraction
10.1 Mark the water meniscus on the
side of the sample bottle for later deter-
mination of sample volume. Pour the
entire sample into a two-liter separatory
funnel.
10.2 Add 60 mL methylene chloride
to the sample bottle, seal, and shake
30 seconds to rinse the inner surface.
Transfer the solvent to the separatory
funnel and extract the sample by
shaking the funnel for two minutes
with periodic venting to release excess
pressure. Allow the organic layer to
separate from the water phase for a
minimum of TO minutes. If the emulsion
interface between layers is more than
one-third the volume of the solvent
layer, the analyst must employ me-
chanical techniques to complete the
phase separation. The optimum tech-
nique depends upon the sample, but
may include stirring, filtration of the
emulsion through glass wool, centrifu-
gation, or other physical methods.
Collect the methylene chioride extract
in a 250-ml. Erlenmeyer flask.
10.3 Add a second 60-mL volume of
methylene chloride to the sample bottle
and repeat the extraction procedure a
second time, combining the extracts in
the Erlenmeyer flask. Perform a third
extraction in the same manner.
10.4 Assemble a Kuderna-Danish
(K-D) concentrator by attaching a,
10-mL concentrator tube to a 500-rnL
evaporative flask. Other concentration
devices or techniques may be used in
place of the Kuderna Danish if the
requirements of Section 8.2 are met.
10.5 Pour the combined extract
through a drying column containing
about 10 cm of anhydrous sodium
sulfate, and collect the extract in the
K-D concentrator. Rinse the Erlenmeyer
flask and column with 20 to 30 ml of
methylene chloride to complete the
quantitative transfer.
10.6 Add one or two clean boiling
chips to the evaporative flask and
attach a three-ball Snyder column.
Prewet the Snyder column by adding
about 1 ml. methylene chloride to the
top. Place the K-D apparatus on a hot
water bath (60 to 65 °C) so that the
concentrator tube is partially immersed
in the hot water and the entire lower
rounded surface of the flask is bathed
with hot vapor. Adjust the vertical
position of the apparatus and the water
temperature as required to complete
the concentration in 1 5 to 20 minutes.
At the proper rate of distillation the
balls of the column will actively chatter
but the chambers will not flood with
condensed solvent. When the apparent
volume of liquid reaches 1 mL, remove
the K-D apparatus and allow it to drain
and cool for at least 1 0 minutes.
10.7 Increase the temperature of the
hot water bath to about 80 °C.
Momentarily remove the Snyder
column, add 50 mL of hexane and a
new boiling chip and reattach the
Snyder column. Prewet the column by
adding about 1 mL of hexane to the
top. Concentrate the solvent extract as
before. The elapsed time of concentra-
tion should be 5 to 10 minutes. When
the apparent volume of liquid reaches 1
mL, remove the K-D apparatus and
allow it to drain and cool at least 1 0
minutes.
608-5
July 1982
-------
10.8 Remove the Snyder column and
rinse the flask and its lower joint into
the concentrator tube with 1 to 2 ml
of hexane, A 5-mL syringe is recom-
mended for this operation. Stopper the
concentrator tube and store
refrigerated if further processing will
not be performed immediately. If the
extracts will be stored longer than two
days, they should be transferred to
Teflon-sealed screw-cap bottles. If the
sample extract requires no further
cleanup, proceed with gas chromato-
graphic analysis. If the sample requires
cleanup proceed to Section 1 1.
10.9 Determine the original sample
volume by refilling the sample bottle to
the mark and transferring the liquid to a
1000-mL graduated cylinder. Record
the sample volume to the nearest 5 ml.
11. Cleanup and Separation
11.1 Cleanup procedures may not be
necessary for a relatively clean sample
matrix. The cleanup procedures recom-
mended in this method have been used
for the analysis of various clean waters
and industrial effluents. If particular
circumstances demand the use of an
alternative cleanup procedure, the
analyst must determine the elution
profile and demonstrate that the
recovery of each compound of interest
is no less than 85%. The Florisil
column allows for a select fractionation
of the compounds and will eliminate
polar materials. Elemental sulfur
interferes with the electron capture gas
chromatography of certain pesticides,
but can be removed by the techniques
described below.
11.2 Florisil column cleanup:
11.2.1 Add a weight of Florisil
(nominally 21 g) predetermined by cali-
bration (Section 7.4 and 7.5), to a
chromatographic column. Settle the
Florisil by tapping the column. Add
sodium sulfate to the top of the Florisil
to form a layer 1 to 2 cm deep. Add 60
mL of hexane to wet and rinse the
sodium sulfate and Florisil. Just prior to
exposure of the sodium sulfate to air,
stop the elution of the hexane by
closing the stopcock on the chroma-
tography column. Discard the eluate.
11.2.2 Adjust the sample extract
volume to 10 mL with hexane and
transfer it from the K-D concentrator
tube to the Florisil column. Rinse the
tube twice with 1 to 2 ml hexane,
adding each rinse to the column.
11.2.3 Place a 500-mL K-D flask and
clean concentrator tube under the
chromatography column. Drain the
column into the flask until the sodium
sulfate latyer is nearly exposed. Eiute
the column with 200 ml of 6% ethyl
ether in hexane (V/V) (Fraction 1) using
a drip rate of about 5 mL/min. Remove
the K-D flask and set aside for later
concentration. Elute the column again,
using 200 ml of 1 5% ethyl ether in
hexane (V/VHFraction 2), into a second
K-D flask. Perform the third elution
using 200 ml of 50% ethyl ether in
hexane (V/VMFraction 3). The elution
patterns for the pesticides an PCB's are
shown in Table 2.
/1.2.4 Concentrate the eluates by
standard K-D techniques (Section
10.6), substituting hexane for the
glassware rinses and using the water
bath at about 85 °C. Adjust final
volume to 10 mL with hexane. Analyze
by gas chromatography.
11.3 Elemental sulfur will usually
elute entirely in Fraction 1 of the Florisil
column cleanup. To remove sulfur
interference from this fraction or the
original extract, pipet 1.00 mL of the
concentrated extract into a clean con-
centrator tube or Teflon-sealed vial.
Add one to three drops of mercury and
seald3i. Agitate the contents of the
vial for 1 5 to 30 seconds. Prolonged
shaking (two hours) may be required. If
so, this may be accomplished with a
reciprocal shaker. Alternatively,
activated copper powder may be used
for sulfur removal'!*). Analyze by gas
chromatography.
12. Gas Chromatography
12.1 Table 1 summarizes the
recommended operating conditions for
the gas chromatograph. This table
includes retention times and MDL that
were obtained under these conditions.
Examples of the parameter separations
achieved by column 1 are shown in
Figures 1 to 10. Other packed
columns, chromatographic conditions,
or detectors may be used if the
requirements of Section 8.2 are met.
Capillary (open-tubular) columns may
also be used if the relative standard
deviations of responses for replicate
injections are demonstrated to be less
than 6% and the requirements of
Section 8.2 are met.
12.2 Calibrate the system daily as
described in Section 7.
12.3 If the internal standard
approach is being used, the internal
standard must be added to the sample
extract and mixed thoroughly
immediately, before injection into the
instrument.
12.4 Inject 2 to 5 j^L of the sample
extract using the solvent-flush
technique'! 5). Smaller (1.0 ^iL) volumes
can be injected if automatic devices are
employed. Record the volume injected
to the nearest 0.05 vL, the total
extract volume, and the resulting peak
size in area or peak height units.
12.5 The width of the retention time
window used to make identifications
should be based upon measurements
of actual retention time variations of
standards over the course of a day.
Three times the standard deviation of a
retention time for a compound can be
used to calculate a suggested window
size; however, the experience of the
analyst should weigh heavily in the
interpretation of chromatograms.
12.6 If the response for the peak
exceeds the working range of the
system, dilute the extract and
reanalyze.
12.7 If the measurement of the peak
response is prevented by the presence
of interferences, further cleanup is
required.
13. Calculations
13.1 Determine the concentration of
individual compounds in the sample.
13.1.1 If the external standard
calibration procedure is used, calculate
the amount of material injected from
the peak response using the calibration
curve or calibration factor in Section
7.2.2. The concentration in the sample
can be calculated from equation 2:
Eq. 2. Concentration,
(A)(Vt)
s
where:
A = Amount of material injected, in
nanograms.
V, = Volume of extract injected
(ML).
V, = Volume of total extract (^L).
Vs = Volume of water extracted
(ml).
13. 1.2 If the internal standard cali-
bration procedure was used, calculate
the concentration in the sample using
the response factor (RF) determined in
Section 7.3.2 and equation 3.
Eq. 3
Concentration, Mg/L =
(At)(lt)
where:
As = Response for the parameter to
be measured.
Ajg = Response for the internal
standard.
I, = Amount of internal standard
added to each extract (pg).
V0 = Volume of water extracted, in
liters.
608-6
July f982
-------
13.2 When it is apparent that two or
more PCB (Aroclor) mixtures are
present, the Webb and McCall
procedure1161 may be used to identify
and quantify the Aroclors.
13.3 For multicomponent mixtures
(chlordane, toxaphene and PCBs)
match retention times of peaks in the
standards with peaks in the sample.
Quantitate every identifiable peak
unless interference with individual
peaks persist after cleanup. Add peak
height or peak area of each identified
peak in the chromatogram. Calculate
as total response in the sample versus
total response in the standard.
13.4 Report results in micrograms
per liter without correction for recovery
data. When duplicate and spiked
samples are analyzed, report all data
obtained with the sample results.
13.5 For samples processed as part
of a set where the laboratory spiked
sample recovery falls outside of the
control limits in Section 8.3, data for
the affected parameters must be
labeled as suspect.
14. Method Performance
14.1 The method detection limit
(MDU is defined as the minimum
concentration of a substance that can
be measured and reported with 99%
confidence that the value is above
zero!11. The MDL concentrations listed
in Table 1 were obtained using reagent
water<171. Similar results were achieved
using representative wastewaters.
14.2 This method has been tested
for linearity of spike recovery from
reagent water and has been demon-
strated to be applicable over the
concentration range from 4 x MDL up
to 1000 x MDL with the following
exceptions: Chlordane recovery at 4 x
MDL was low (60%); Toxaphene
recovery was demonstrated linear over
the range of 10 x MDL to 1000 x
MDL<17>.
14.3 In a single laboratory (South-
west Research Institute), using spiked
wastewater samples, the average
recoveries presented in Table 3 were
obtained141. Each spiked sample was
analyzed in triplicate on two separate
days. The standard deviation of the
percent recovery is also included in
Table 3.
14.4 The U.S. Environmental Protec-
tion Agency is in the process of
conducting an interlaboratory method
study to fully define the performance
of this method.
References
1 See Appendix A
2. "Determination of Pesticides and
PCBs in Industrial and Municipal
Wastewaters." Report for EPA
Contract 68-03-2606. In preparation.
3. ASTM Annual Book of Standards,
Part 31, D3694. "Standard Practice
for Preparation of Sample Containers
and for Preservation," American
Society for Testing and Materials,
Philadelphia, PA, p. 67S, 1980.
4. Giam, D.S., Chan H.S. and Nef,
G.S., "Sensitive Method for
Determination of Phthalate Ester
Plasticizers in Open-Ocean Biota
Samples," Analytical Chemistry, 47,
2225, (1975).
5. Giam, C.S., Chan, H.S., "Control of
Blanks in the Analysis of Phthslates in
Air and Ocean Biota Samples," U.S.
National Bureau of Standards. Special
Publication 442, pp. 701-708, 1976.
6. "Carcinogens-Working With
Carcinogens," Department of Health,
Education, and Welfare, Public Health
Service, Center for Disease Control,
National Institute for Occupational
Safety and Health. Publication No.
77-206, Aug. 1977.
7. "OSHA Safety and Health
Standards, General Industry," (29 CFR
1 91 0), Occupational Safety and
Health Administration, OSHA 2206,
(Revised, January 1976).
8. "Safety in Academic Chemistry
Laboratories," American Chemical
Society Publication, Committee on
Chemical Safety, 3rd Edition, 1 979.
9. Mills, P.A., "Variation of Florisil
Activity: Simple Method for Measuring
Absorbent Capacity and Its Use in
Standardizing Florisil Columns,"
Journal of the Association of Official
Analytical Chemists, 51, 29 H968I.
10. "Handbook for AnalyticafQuality
Control in Water and Wastewatei
Laboratories," EPA-600/4-79-01 9,
U.S. Environmental Protection Agency,
Environmental Monitoring and Support
Laboratory, Cincinnati, Ohio 45268,
March 1979.
11. ASTM Annual Book of Standards,
Part 31, D3370, "Standard Practice
for Sampling Water," American
Society for Testing and Materials,
Philadelphia, PA. p. 76, 1980.
1 2. "Methods 330.4 (Titrimetric,
DPD-FAS) and 330.5 (Spectrophoto-
metric, DPD) for Chlorine, Total
Residual," Methods for Chemical
Analysis of Water and Wastes, EPA
600-4/79-020, U.S. Environmental
Protection Agency, Environmental
Monitoring and Support Laboratory,
Cincinnati, Ohio 45268, March 1979.
1 3. Goerlitz, D.F. and Law, L.M.,
Bulletin for Environmental
Contamination and Toxicology, 6 9
(1971).
14. "Manual of Analytical Methods for
the Analysis of Pesticides in Human
Environmental Samples," U.S. Environ-
mental Protection Agency, Health
Effects Research Laboratory, Research
Triangle Park, N.C., EPA Report
600/8-80-038, Section 1 1,B, p.6.
1 5. Burke, J.A., "Gas Chromatography
for Pesticide Residue Analysis; Some
Practical Aspects," Journal of the
Association of Official Analytical
Chemists, 48, 1037(1965).
16. Webb, R.G., and McCall, A.C.,
"Quantitative PCB Standards for
Electron Capture Gas
Chromatography," Journal of
Chromatographic Science, 11, 366
(1973).
1 7. "Method Detection Limit and
Analytical Curve Studies, EPA Methods
606, 607, and 608," Special letter
report for EPA Contract 68-03-2606.
Environmental Monitoring and Support
Laboratory-Cincinnati, Ohio 45268.
608-7
July 1982
-------
Table 1. Chrom
Detect
Parameter
o-BHC
y-BHC
P-BHC
Heptachlor
6-BHC
Aldrin
Hepachlor epoxide
Endosulfan 1
4,4 '-DDE
Dieldrin
Endrin
4,4 '-ODD
Endosulfan II
4,4 '-DDT
Endrin aldehyde
Endosulfan sulfate
Chlordane
Toxaphene
PCB-1016
PCB-1221
PCB- 1232
PCB-1242
PCB- 1248
PCB- 1254
PCB- 12 60
atographic Conditions ar
ion Limits
Retention Time
(min.) r
Column 1
1.35
.70
1.90
2.00
2.15
2.40
3.50
4.50
5.13
5.45
6.55
7.83
8.00
9.40
11.82
14.22
mr
mr
mr
mr
mr
mr
mr
mr
mr
Column 2
1.82
2.13
1.97
3.35
2.20
4.10
5.00
6.20
7.15
7.23
8.10
9.08
8.28
11.75
9.30
10.70
mr
mr
mr
mr
mr
mr
mr
mr
mr
td Method
Method
Detection Limit
W/L
0.003
0.004
0.006
0.003
0.009
0.004
0.083
0.014
0.004
0.002
0.006
0.01 1
0. 004
0.012
0. 023
0.066
0.014
0.24
nd
nd
nd
0.065
nd
nd
nd
Column 1 conditions: Supelcoport (100/120 mesh) coated
with 1.5%SP-2250/1.95%SP-2401packedina 1.8m
long x 4 mm ID glass column with 5% Methane/95%
Argon carrier gas at a flow rate of 60 mL/min. Column
temperature isothermal at 200 °C, except for PCB-1016
through PCB-1248, which should be measured at
Column 2 conditions: Supelcoport (100/120 mesh) coated
with 3% 0V-1 in a 1.8m long x 4 mm ID glass column
with 5 % Methane/95% Argon carrier gas at a flow rate of
60 mL/min. Column temperature, isothermal at 200 °C
for the pesticides; 140°C for PCB-1221 and 1232-
1 70 °C for PCB-1016 and 1242 to 1268.
mr - Multiple peak response. See Figures 2 thru 10.
nd — Not determined.
Table 2. Distribution of Chlorinated Pesticides and PCBs
into Florisil Column Fractions2
Percent Recovery
by Fraction
Parameter
Aldrin
a-BHC
0-BHC
6-BHC
Y-BHC
Chlordane
4,4'-DDD
4, 4 '-DDE
4, 4 '-DDT
Dieldrin
Endosulfan 1
Endosulfan
Endosulfan sulfate
Endrin
Endrin aldehyde
Heptachlor
Heptachlor epoxide
Toxaphene
PCB-1016
PCB-1221
PCB- 1232
PCB-1242
PCB- 1248
PCB- 12 54
PCB- 1260
Fraction
1
100
100
97
98
100
100
99
98
100
0
37
0
0
4
0
100
100
96
97
97
95
97
103
90
95
Fraction
2
100
64
7
0
96
68
4
Fraction
3
91
106
26
Fraction 1-6% ethyl ether in hexane
Fraction 2-15% ethyl ether in hexane
Fraction 3- 50% ethyl ether in hexane
608-6
July 1982
-------
Table 3. Single Operator Accuracy and Precision
Parameter
_ _— — —
Aldrin
o-BHC
P-BHC
6-BHC
rBHC
I v
Chlorane
4-4 '-ODD
4, 4' -DDE
4, 4 '-DDT
Dieldrin
Endosulfan 1
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Heptachlor
Heptachlor epoxide
Toxaphene
PCB-1016
PCB-1221
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCB-1260
Average
Percent
Recovery
— — —
89
89
88
86
97
93
92
89
92
95
96
97
99
95
87
88
93
95
94
96
88
92
90
92
91
Standard
Deviation
%
2.5
2.0
1.3
3.4
3.3
4. 1
1.9
2.2
3.2
2.8
2.9
2.4
4.1
2. 1
2.1
3.3
1.4
3.8
1.8
4.2
2.4
2.0
1.6
3.3
5.5
Spike
Range
(W/U
•.MI i ~
2.0
/f\
.0
2f*
.0
2.0
;f\ •
.0
20
6.0
3r\
.0
8.0
3 A
.0
3.0
5.0
15
5f\
.O
12
/f\
.0
2.0
200
25
55-110
1 10
28-56
40
40
80
Number
of
Analyses
.•i in
15
15
15
15
15
21
15
15
15
15
12
14
15
12
11
12
15
18
12
12
12
12
12
18
18
Column: 1.5% SP-2250+
1.95% SP-2401 on Supelcoport
Temperature: 200°C.
Detector: Electron capture
0 4 8 12 16
Retention time, minutes
Figure 1. Gas chromatogrem of pesticides.
608-9
Matrix
Types
3
3
3
3
3
4
3
3
3
2
2
3
3
2
2
2
3
3
2
2
2
2
2
3
3
Column: 1.5%SP-2250+
1.95% SP-2401 on
Supelcoport
Temperature: 200°C.
Detector: Electron capture
4 8 12
Retention time, minutes
Figure 2. Gas chromatogram
of chlordane.
16
July 1982
-------
Column: 1.5% SP-2250-
1.95% SP-2401 on
Supelcopon
Temperature: 200°C.
Detector: Electron capture
6 10 14 18 22
Retention time, minutes
Figure 3. Gas chromatogram of toxaphene.
Column: 1.5% SP-2250* 1.95% SP-2401 on
Supelcopon
Temperature: 160°C.
Detector: Electron capture
26
2 6 10 14 18
Retention time, minutes
Figure 4. Gas chromatogram of PCB-1016.
608-10
22
Column: 1.5% SP-2250* 1.95% SP-2401 on
Supelcopon
Temperature: 160°C.
Detector: Electron capture
-L.
6 10 14 18
Retention time, minutes
22
Figure 6. Gas chromatogram of PCB-1221.
Column: 1.5% SP-2250* 1.95% SP-2401 on
Supelcopon
Temperature: 160°C.
Detector: Electron capture
2 6 10 14 18
Retention time, minutes
Figure 6. Gas chromatogram of PCB-1232.
July 1982
22
24
-------
Column: 1.5% SP-2250+ 1.95% SP-2401 on
Supelcoport
Temperature: 160°C.
Detector: Electron capture
26 10 14 18
Retention time, minutes
Figure 7. Gas chromatogram of PCB-1242.
22
Column: 1.5% SP-2250+ 1.95% SP-2401 on
Supelcoport
Temperature: 200°C.
Detector: Electron capture
.1 t
2 6 10 14 18
Retention time, minutes
Figure 9. Gas chromatogram of PCB-1254.
22
Column: 1.5% SP-2250+ 1.95% SP-2401 on
Supelcoport
Temperature: 160°C.
Detector: Electron capture
2 6 10 14 , 18 22
Retention time, minutes
Figur* 8. Gas chromatcgram of PCB-1248.
608-11
Column: 1.5% SP-2250+ 1.95% SP-2401 on
Supelcoport
Temperature: 200°C.
Detector: Electron capture
2 6 10 14 18 22
Retention time, minutes
Figure 10. Gas chromatogram of PCB-1260.
26
July 1982
U.S GOVERNMENT PRINTING OFFICE: 19M 759- 102/09-H
-------
-------
METHOD T06 Revision 1.0
September, 1986
METHOD FOR THE DETERMINATION OF PHOSGENE
IN AMBIENT AIR USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
1. Scope
1.1 This document describes a method for determination of
phosgene in ambient air, in which phosgene is collected by
passage of the air through a solution of aniline, forming
carbanilide. The carbanilide is determined by HPLC. The method
can be used to detect phosgene at the 0.1 ppbv level.
1.2 Precision for phosgene spiked into a clean air stream is
^15-20% relative standard deviation. Recovery is quantita-
tive within that precision, down to less than 3 ppbv. This
method has been developed and tested by a single
laboratory(D, and, consequently, each laboratory desiring
to use the method should acquire sufficient precision
and recovery data to verify performance under those
particular conditions. This method is more sensitive,
and probably more selective, than the standard colorimetric
procedure currently in widespread use for workplace monitor-
1ng(2).
2. Applicable Documents
2.1 ASTM Standards
D1356 - Definitions of Terms Related to Atmospheric Sampling
and Analysis(3).
2.2 Other Documents
Standard NIOSH Procedure for Phosgene(2).
U.S. EPA Technical Assistance Document^).
-------
T06-2
3. Summary of Method
3.1 Ambient air is drawn through a midget impinger containing
10 ml of 2/98 aniline/toluene (by volume). Phosgene
readily reacts with aniline to form carbanilide (1,3-
diphenylurea), which is stable indefinitely.
3.2 After sampling, the impinger contents are transferred to
a screw-capped vial having a Teflon-lined cap and
returned to the laboratory for analysis.
3.3 The solution is taken to dryness by heating to 60°C on an
aluminum heating block under a gentle stream of pure
nitrogen gas. The residue is dissolved in 1 mL of
acetonitrile.
3.4 Carbanilide is determined in the acetonitrile solution
using reverse-phase HPLC with an ultraviolet absorbance
(UV) detector operating at 254 nm.
4. Significance
4.1 Phosgene is widely used in industrial operations, primarily
in the synthetic organic chemicals industry. In addition,
phosgene is produced by photochemical degradation of
chlorinated hydrocarbons (e.g., trichloroethylene) emitted
from various sources. Although phosgene is acutely
toxic, its effects at low levels (i.e., 1 ppbv and below)
are unknown. Nonetheless, its emission into and/or
formation in ambient air is of potential concern.
4.2 The conventional method for phosgene has utilized a
colorimetric procedure involving reaction with
4,4'-nitrobenzyl pyridine in diethyl phthalate. This
method cannot detect phosgene levels below 10 ppbv and
is subject to numerous interferences. The method described
herein is more sensitive (0.1 ppbv detection limit) and
is believed to be more selective due to the chromatographic
separation step. However, the method needs to be more
rigorously tested for interferences before its degree
of selectivity can be firmly established.
-------
T06-3
5. Definitions
Definitions used in this document and in any user-prepared
• SOPs should be consistent with ASTM D1356 (3). All
abbreviations and symbols are defined within this
document at the point of use.
6. Interferences
6.1 There are very few interferences in the method, although
this aspect of the method needs to be more thoroughly
investigated. Ambient levels of nitrogen oxides, ozone,
water vapor, and S02 are known not to interfere. Chloroformates
can cause interferences by reacting with the aniline to form
urea, which produces a peak that overlies the carbanilide
peak in the HPLC trace. Presence of chloroformates should be
documented before use of this method. However, the inclusion
of a HPLC step overcomes most potential interferences from
other organic compounds. High concentrations of acidic materials
can cause precipitation of aniline salts in the impinger, thus
reducing the amount of available reagent.
6.2 Purity of the aniline reagent is a critical factor, since
traces of carbanilide have been found in reagent-grade
aniline. This problem can be overcome by vacuum distil-
lation of aniline in an all-glass apparatus.
7. Apparatus
7.1 Isocratic high performance liquid chromatography (HPLC)
system consisting of a mobile-phase reservoir, a high-pressure
pump, an injection valve, a Zorbax ODS or C-18 reverse-phase
column, or equivalent (25 cm x 4.6 mm ID), a variable-wavelength
UV detector operating at 254 nm, and a data system or strip-
chart recorder (Figure 1).
7.2 Sampling system - capable of accurately and precisely
sampling 100-1000 mL/minute of ambient air (Figure 2).
-------
T06-4
7.3 Stopwatch.
7.4 Friction-top metal can, e.g., one-gallon (paint can) - to
hold sampling reagent and samples.
7.5 Thermometer - to record ambient temperature.
7.6 Barometer (optional).
7.7 Analytical balance - 0.1 mg sensitivity.
7.8 Midget impingers - jet inlet type, 25 ml.
7.9 Nitrogen evaporator with heating block - for concentrating
samples.
7.10 Suction filtration apparatus - for filtering HPLC
mobile phase.
7.11 Volumetric flasks - 100 ml and 500 mL.
7.12 Pipettes - various sizes, 1-10 ml.
7.13 Helium purge line (optional) - for degassing HPLC
mobile phase.
7.14 Erlenmeyer flask, 1-L - for preparing HPLC mobile
phase.
7.15 Graduated cylinder, 1 L - for preparing HPLC mobile
phase.
7.16 Microliter syringe, 10-25 uL - for HPLC injection.
8. Reagents and Materials
8.1 Bottles, 16 02. glass, with Teflon-lined screw cap - for
storing sampling reagent.
8.2 Vials, 20 mL, with Teflon-lined screw cap - for holding
samples and extracts.
8.3 Granular charcoal.
8.4 Acetonitrile, toluene, and methanol - distilled in glass
or pesticide grade.
8.5 Aniline - 99+%, gold label from Aldrich Chemical Co., or
equivalent.
-------
T06-5
8.6 Carbanilide - highest purity available; Aldrich Chemical
Co., or equivalent.
8.7 Nitrogen, compressed gas cylinder - 99.99% purity for
sample evaporation.
8.8 Polyester filters, 0.22 urn - Nuclepore, or equiv.
9. Preparation of Sampling Reagent
9.1 Sampling reagent is prepared by placing 5.0 ml of aniline in
a 250-mL volumetric flask and diluting to the mark with toluene,
The flask is inverted 10-20 times to mix the reagent. The
reagent is then placed in a clear 16-ounce bottle with a
Teflon-lined screw cap. The reagent is refrigerated until use.
9.2 Before use, each batch of reagent is checked for purity by
analyzing a 10-mL portion according to the procedure described
in Section 11. If acceptable purity (<50 ng of carbanilide
per 10 ml of reagent) is not obtained, the aniline or toluene
is probably contaminated.
10. Sampling
10.1 The sampling apparatus is assembled and should be similar
to that shown in Figure 2. EPA Method 6 uses essentially
the same sampling system (5). All glassware (e.g.,
impingers, sampling bottles, etc.) must be thoroughly
rinsed with methanol and oven-dried before use.
10.2 Before sample collection, the entire assembly (including
empty sample impingers) is installed and the flow rate
checked at a value near the desired rate. Flow rates
greater than 1000 mL/minute (^2%) should not be used because
impinger collection efficiency may decrease. Generally,
calibration is accomplished using a soap bubble flow
-------
T06-6
meter or calibrated wet test meter connected to the flow
exit, assuming that the entire system is sealed. ASTM Method
D3686 describes an appropriate calibration scheme that does
not require a sealed-flow system downstream of the pump (3).
10.3 Ideally, a dry gas meter is included in the system to record
total flow, if the flow rate is sufficient for its use.
If a dry gas meter is not available, the operator must measure
and record the sampling flow rate at the beginning and end of
the sampling period to determine sample volume. If the
sampling time exceeds two hours, the flow rate should be
measured at intermediate points during the sampling period.
Ideally, a rotameter should be included to allow observation of
the flow rate without interruption of the sampling process.
10.4 To collect an air sample, the midget impingers are
loaded with 10 ml each of sampling reagent. The impingers
are installed in the sampling system and sample flow is
started. The following parameters are recorded on the
data sheet (see Figure 3 for an example): date, sampling
location, time, ambient temperature, barometric pressure
(if available), relative humidity (if available), dry
gas meter reading (if appropriate), flow rate, rotameter
setting, sampling reagent batch number, and dry gas meter
and pump identification numbers.
10.5 The sampler is allowed to operate for the desired period,
with periodic recording of the variables listed above.
The total flow should not exceed 50 L. If it does, the
operator must use a second impinger.
10.6 At the end of the sampling period, the parameters listed
in Section 10.4 are recorded and the sample flow is stopped.
If a dry gas meter is not used, the flow rate must be checked
at the end of the sampling interval. If the flow rates at the
beginning and end of the sampling period differ by more than
15%, the sample should be marked as suspect.
-------
T06-7
10.7 Immediately after sampling, the impinge r is removed from
the sampling system. The contents of the impinger are
emptied into a clean 20-mL glass vial with a Teflon-
' lined screw cap. The impinger is then rinsed with
2-3 ml of toluene and the rinse solution is added to the
vial. The vial is then capped, sealed with Teflon tape,
and placed in a friction-top can containing 1-2 inches
of granular charcoal. The samples are stored in the
can and refrigerated until analysis.
10.8 If a dry gas meter or equivalent total flow indicator
is not used, the average sample flow rate must be calculated
according to the following equation:
Q! + Q2 •••• QN
QA
where
Q2
Q/\ = average flow rate (mL/minute).
QN = flow rates determined at the beginning, end,
and intermediate points during sampling.
N = number of points averaged.
10.9 The total flow is then calculated using the following
equation:
Vm =
(T2-Ti)QA
1000
where
Vm = total sample volume (L) at measured
temperature and pressure.
T2 = stop time.
TI = start time.
-T2 = total sampling time (minutes).
Qa = average flow rate (mL/minute).
-------
T06-8
11. Sample Analysis
11.1 Sample Preparation
11.1.1 The samples are returned to the laboratory in 20-ml
screw-capped vials and refrigerated in charcoal
containing cans until analysis.
11.1.2 The sample vial is placed in an aluminum
heating block maintained at 60°C and a gentle
stream of pure nitrogen gas is directed
across the sample.
11.1.3 When the sample reaches complete dryness, the vial
is removed from the heating block, capped, and
cooled to near room temperature. A 1-mL volume
of HPLC mobile phase (50/50 acetonitrile/water)
is placed in the vial. The vial is then capped
and gently shaken to dissolve the residue.
11.1.4 The concentrated sample is then refrigerated
until HPLC analysis, as described in Section 11.2.
11.2 HPLC Analysis
11.2.1 The HPLC system is assembled and calibrated as described in
Section 12. The operating parameters are as follows:
Column: C-18 RP
Mobile Phase: 30% acetonitrile/70% distilled water
Detector: ultraviolet, operating at 254 nm
Flow Rate: 1 mL/min
Before each analysis, the detector baseline is checked
to ensure stable operation.
11.2.2 A 25-uL aliquot of the sample, dissolved in HPLC
mobile phase, is drawn into a clean HPLC injection
syringe. The sample injection loop is loaded and
an injection is made. The data system is activated
simultaneously with the injection and the point of
injection is marked on the strip-chart recorder.
-------
T06-9
11.2.3 After approximately one minute, the injection valve
is returned to the "load" position and the syringe and
valve are flushed with mobile phase in preparation
for the next sample analysis.
11.2.4 After elution of carbanilide, data acquisition is
terminated and the component concentrations are
calculated as described in Section 13.
11.2.5 Once a stable baseline is achieved, the system can be
used for further sample analyses as described above.
11.2.6 If the concentration of carbanilide exceeds the
linear range of the instruments, the sample should
be diluted with mobile phase, or a smaller volume
can be injected into the HPLC.
11.2.7 If the retention time is not duplicated, as determined
by the calibration curve, you may increase or decrease
the acetonitrile/water ratio to obtain the correct elution
time, as specified in Figure 4. If the elution time is too
long, increase the ratio; if it is too short, decrease the
ratio.
11.2.8 If a dirty column causes improper detection of carbanilide,
you may reactivate the column by reverse solvent flushing
utilizing the following sequence: water, methanol,
acetonitrile, dichloromethane, hexane, acetonitrile,
then 50/50, acetonitrile in water.
12. HPLC Assembly and Calibration
12.1 The HPLC system is assembled and operated according to the
parameters outlined in Section 11.2.1. An example of a typical
chromatogram oabtained using the above parameters is shown in
Figure 4.
12.2 The mobile phase is prepared by mixing 500 mL of acetonitrile
and 500 mL of reagent water. This mixture is filtered
through a 0.22-um polyester membrane filter in an all-glass
and Teflon suction filtration. A constant back pressure
restrictor (50 psi) or short length (6-12 inches) of 0.01-inch
I.D. Teflon tubing should be placed after the detector to
eliminate further mobile phase outclassing.
-------
T06-10
12.3 The mobile phase is placed in the HPLC solvent reservoir and
the pump is set at a flow rate of 1 mL/minute and allowed to
pump for 20-30 minutes before the first analysis. The detector
is switched on at least 30 minutes before the first analysis
and the detector output is displayed on a strip-chart recorder
or similar output device at a sensitivity of ca 0.008 absorbance
units full scale (AUFS). Once a stable baseline is achieved,
the system is ready, for calibration.
12.4 Carbanilide standards are prepared in HPLC mobile phase.
A concentrated stock solution of 100 mg/L is prepared by
dissolving 10 mg of carbanilide in 100 ml of mobile phase.
This solution is used to prepare calibration standards
containing concentrations of 0.05-5 mg/L.
12.5 Each calibration standard (at least five levels) is analyzed
three times and area response is tabulated against mass injected.
All calibration runs are performed as described for sample
analyses in Section 11. Using the UV detector, a linear
response range (Figures 5a through 5e) of approximately 0.1 to
10 mg/L should be achieved for a 25-uL injection volumes. The
results may be used to prepare a calibration curve, as illus-
trated in Figure 6. Linear response is indicated where a corre-
lation coefficient of at least 0.999 for a linear least-squares
fit of the data (concentration versus area response) is obtained.
12.6 Once linear response has been documented, an intermediate
concentration standard near the anticipated levels for ambient
air, but at least 10 times the detection limit, should be
chosen for daily calibration. The response for carbanilide
should be within 10% day to day. If greater variability is
observed, more frequent calibration may be required to ensure
that valid results are obtained or a new calibration curve
must be developed from fresh standards.
12.7 The response for carbanilide in the daily calibration standard
is used to calculate a response factor according to the following
equation:
-------
where
RFC =
T06-11
Cc X Vj
RC
RFC = response factor (usually area counts) for
carbanilide in nanograms injected/response
unit.
Cc = concentration (mg/L) of carbanilide in the
daily calibration standard.
Vi = volume (uL) of calibration standard injected
Rc = response (area counts) for carbanilide in
calibration standard.
13. Calculations
13.1 The volume of air sampled is often reported unconnected for
atmospheric conditions (i.e., under ambient conditions).
The value should be adjusted to standard conditions
(25°C and 760 mm pressure) using the following equation:
where
Vs ' Vm
298
760 273 + TA
Vs = total sample volume (L) at 25°C and 760 mm Hg
pressure.
Vm = total sample volume (L) under ambient conditions,
calculated as in Section 10.9 or from dry gas
meter reading.
PA = ambient pressure (mm Hg).
TA = ambient temperature (°C).
-------
T06-12
13.2 The concentration of carbanilide is calculated for each
sample using the following equation:
Wd = RFC X Rd X J
V
VI
where
Wd = total quantity of carbanilide (ug) in the sample,
RFC = response factor calculated in Section 12.7.
Rd = response (area counts or other response units)
for carbanilide in sample extract.
VE = final volume (mL) of sample extract.
Vj = volume (uL) of extract injected into the HPLC
system.
13.3 The concentration of phosgene in the original sample is
calculated from the following equation:
C. • "d 99
A Vm (or vs) " In " 100°
where
CA = concentration of phosgene (ng/L)in the original
sample.
Wd = total quantity of carbanilide (ug) in sample.
Vm = total sample volume (L) under ambient conditions.
Vc = total sample volume (L) at 25 °C and 760 mm Hg.
_99 = the molecular weights (g/mole) of phosgene and
212 carbanilide are 99 and 212 g/mole, respectively.
13.4 The phosgene concentrations can be converted to ppbv using the
following equation:
-------
T06-13
/L) x
where
CA (ppbv) - CA (ng/L) x 244
CA (ng/L) is calculated using Vs-
14 Performance Criteria and Quality Assurance
This section summarizes retired quality assurance (QA) measures and
provides guidance concerning performance criteria that should be
achieved within each laboratory.
14.1
Standard Operating Procedures (SOPs)
14.L1 Users should generate SOPs describing ^*"<«"
activities in their laboratory: 1) assembly, calibra
tion, and operation of the sampling system with make
and model of equipment used; 2) preparation, purifica-
tion, storage, and handling of sampling reagent and
samples; 3) assembly, calibration, and operation of
the HPLC system with make and model of equipment used;
and 4) all aspects of data recording and process! ng.
including lists of computer hardware and software used,
14 l 2 SOPs should provide specific stepwise instructions
and should be readily available to and understood
by the laboratory personnel conducting the work.
14.2 HPLC System Performance
14 2.1 The general appearance of the HPLC chromatogram
should be similar to that illustrated in Figure 4.
14 2 2 The HPLC system efficiency and peak asymmetry
' factor should be determined in the following manner:
-------
T06-14
A solution of carbanilide corresponding to at
least 20 times the detection limit should be
Injected with the recorder chart sensitivity
and speed set to yield a peak approximately
75% of full scale and 1 cm wide at half height.
The peak asymmetry factor is determined as shown
in Figure 7,.and should be between 0.8 and 1.8.
14.2.3 HPLC system efficiency is calculated according to
the following equation:
N = 5.54 tr
Wl/2
where
N = column efficiency (theoretical plates).
tr = retention time (seconds) of carbanilide.
Wl/2 = width of component peak at half
height (seconds).
A column efficiency of >5,000 theoretical plates
should be obtained.
14.2.4 Precision of response for replicate HPLC injections
should be +10% or less, day to day, for calibration
standards. Precision of retention times should be +2%.
on a given day.
14.3 Process Blanks
14.3.1 Before use, a 10-mL aliquot of each batch of sampling
reagent should be analyzed as described in Section 11.
The blank should contain less than 50 ng of carbanilide
per 10-mL aliquot.
-------
T06-15
14.3.2 At least one field blank or 10% of the field samples,
whichever is larger, should be shipped and analyzed
with each group of samples. The field blank is treated
. identically to the samples except that no air is drawn
through the reagent. The same performance criteria
described in Section 14.3.1 should be met for process
blanks.
14.4 Method Precision and Recovery
14.4.1 Analysis of replicate samples indicates that a precision
of +15-20% relative standard deviation can be readily
achieved (see Table 1). Each laboratory should collect
parallel samples periodically (at least one for each
batch of samples) to document its precision in conduct-
ing the method.
14.4.2 Precision for replicate HPLC injections should be +10%
or better, day to day, for calibration standards.
14.4.3 Before using the method in the field, each laboratory
must confirm the performance of the method under its
particular conditions. Since static, dilute, gas phase
standards of phosgene are unstable, a dynamic flow/
permeation tub system should be assembled as described
in the literature^). ASTM Method D 3609(3) should be
used as the protocol for operating such a system.
14.4.4 Once a suitable dynamic flow/permeation tube system
has been constructed, a series of three samples from
the outlet gas stream (60 L) should be sampled at three
different spike levels (achieved by adjusting the air
flow through the permeation chamber). Precision and
recovery data comparable to those shown in Table 1
should be achieved.
-------
T06-16
REFERENCES
4'
5-
-------
INJECTION
VALVE
COLUMN
VARIABLE
WAVELENGTH
UV
DETECTOR
DATA
SYSTEM
MOBILE
PHASE
RESERVOIR
STRIPCHART
RECORDER
FIGURE 1. TYPICAL HPLC SYSTEM
-------
SILICA GEL
ROTAMETER
VENT
DRY
TEST
METER
PUMP
SAMPLE
IMPINGERS
7
mm
* '
• 1
L
r
|
*'-<
-
f
L**
Lr
V
M
7.
10 ml of 2/98
Aniline/Toluene
FLOW
o
-------
T06-19
.SAMPLING DATA SHEET
(One Sample per Data Sheet)
PROJECT:
SITE:
DATES(S) SAMPLED:
LOCATION:
TIME PERIOD SAMPLED:
OPERATOR:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
CALIBRATED BY:
Sample Number:
Start Time: _______
Stop Time:
Time
1
•
•3
4
N.
Dry Gas
Meter
Reading
Rotameter
Reading
Flow
Rate,*Q
mL/min
Ambient
Temperature
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
.. «^_^_ M—^— »^— «» ™ '"
Comments
.-Mil 1 •' ™'™
• HI—I II. ........
Total Volume Data1
Vm = (Final - Initial) Dry Gas Meter Reading, or
Q '" Q
x 1
1000 x (Sampling Time in Minutes)
L
L
* Flow rate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
FIGURE 3. TYPICAL SAMPLING DATA FORM
-------
T06-20
\D
•
ro
f
o
UJ
OPERATING PARAMETERS
HPLC
Column: C-18 RP
Mobile Phase: 30% Acetonitrile/70% Distilled Water
Detector: Ultra violet operating at 254 nm
Flow Rate: 1 ml/min
Retention Time: 3.59 minutes
AUG. 22. 1986 15:25:17 CHART 0.50 CM/MIN
RUN #50 CALC *0
COLUMN SOLVENT OPR ID:
EXTERNAL STANDARD QUANTITATION
PEAK* AMOUNT RT EXP RT
2.7530O 2.74
10020.20000 3.59
TOTAL 1002300000
AREA
2753 L
10020345 L
RF
OOOOOOOEO
O.OOOOOOEO
FIGURE 4. CHROMATOGRAM FOR 3 ppbv OF
PHOSGENE SPIKED INTO CLEAN AIR
-------
3.59
OPERATING PARAMETERS
HPLC
Column: C-18 RP
Mobile Phase: 30% Acetonitrile/70% Distilled Water
Detector: Ultra violet operating at 254 nm
Flow Rate: 1 ml/min
Retention Time: 3.59 minutes
(a)
3.55
(b)
3.57
(C)
TIME-
o
UJ
-3
o
UJ
TIME-
o
UJ
-3
z
TIME
3/iQ
CONG
2/tg
5/tg
AREA
COUNTS
2126577
4243289
6312128
8373790
10020345
3.60
(d)
3.59
(e)
FIGURE 5a-5e. HPLC CHROMATOGRAM OF
VARYING CARBANILIDE CONCENTRATIONS
-------
T06-22
CORRELATION COEFFICIENT:
0.9999
OPERATING PARAMETERS
HPLC
Column: C-18 RP
Mobile Phase: 30% Acetonitrile/70% Distilled Water
Detector: Ultra violet operating at 254 nm
Flow Rate: 1 ml/min
Retention Time: 3.59 minutes
2345
CARBANILIDE
FIGURE 6. CALIBRATION CURVE FOR
CARBANILINE
-------
T06-23
BC
Asymmetry Factor = TJT
Example Calculation:
Pea* Height = DE = 100 mm
10% Peak Height = BD = 10 mm
Peak Width at 10% Peak Height -
AB = 11 mm
BC = 12 mm
12
Therefore: Asymmetry Factor =
AC = 23 mm
FIGURE 7. PEAK ASYMMETRY CALCULATION
-------
T06-24
TABLE 1: PRECISION AND RECOVERY DATA
FOR PHOSGENE IN CLEAN AIR
Phosgene
Concentration,
ppbv
0.034
0.22
3.0
4.3
20
Recovery,
63
87
99
109
99
Standard
Deviation
13
14
3
12
14
200 96 7
======================a==-==-=============-==____.
-------
Revision 1.0
September. 1986
METHOD T07
METHOD FOR THE DETERMINATION OF N-NITROSODIMETHYLAMINE
IN AMBIENT AIR USING GAS CHROMATOGRAPHY
1. Scope
1.1 This document describes a method for determination of N-
nitrosodimethyl amine (NDMA) in ambient air. Although the
method, as described, employs gas chromatography/mass
spectrometry (GC/MS), other detection systems are allowed.
1.2 Although additional documentation of the performance of this
method is required, a detection limit of better than 1 ug/m3
is achievable using GC/MS (1,2). Alternate, selective GC
detection systems such as a thermal energy analyzer (2), a
thermionic nitrogen-selective detector (3), or a Hall Electro-
lytic conductivity detector (4) may prove to be more sensitive
and selective in some instances.
2. Applicable Documents
2.1 ASTM Standards
D1356 Definitions of Terms Related to Atmospheric Sampling
and Analysis (5)
2.2 Other Documents
Ambient air studies (1,2)
U.S. EPA Technical Assistance Document (6)
3. Summary of Method
3.1 Ambient air is drawn through a Thermosorb/N adsorbent
cartridge at a rate of approximately 2 L per minute for
an appropriate period of time. Breakthrough has been shown
-------
T07-2
not to be a problem with total sampling volumes of 300 L
(i.e., 150 minutes at 2 L per minute). The selection
of Thermosorb/N absorbent over Tenax GC, was due, in part,
to recent laboratory studies indicating artifact formation
on Tenax from the presence of oxides of nitrogen in the sample
matrix.
3.2 In the laboratory, the cartridges are pre-eluted with 5 ml
of dichloromethane (in the same direction as sample flow) to
remove interferences. Residual dichloromethane is removed by
purging the cartridges with air in the same direction. The
cartridges are then eluted, in the reverse direction, with 2 ml
of acetone. This eluate is collected in a screw-capped vial
and refrigerated until analysis.
3.3 NDMA is determined by GC/MS using a Carbowax 20M capillary
column. NDMA is quantified from the response of the m/e 74
molecular ion using an external standard calibration method.
4. Significance
4.1 Nitrosamines, including NDMA, are suspected human carcinogens.
These compounds may be present in ambient air as a result of
direct emission (e.g., from tire manufacturing) or from atmos-
pheric reactions between secondary or tertiary amines and NOX.
4.2 Several papers (1,2,4) have been published describing analytical
approaches for NDMA detennination. The purpose of this document
is to combine the attractive features of these methods into
one standardized method. At the present time, this method has
not been validated in its final form, and, therefore, one must
use caution when employing it for specific applications.
5. Definitions
Definitions used in this document and in any user-prepared SOPs should
be consistent with ASTM 01356(5). All abbreviations and symbols are
defined within this document at the point of use.
-------
T07-3
6. Interferences
Compounds having retention times similar to NDMA, and yielding
detectable m/e 74 ion fragments, may interfere in the method. The
inclusion of a pre-elution step in the sample desorption procedure
minimizes the number of interferences. Alternative GC columns and
conditions may be required to overcome interferences in unique
situations.
7. Apparatus
7.1 GC/MS System - capable of temperature-programmed, fused-silica
capillary column operation. Unit mass resolution or better to
300 amu. Capable of full scan and selected ion monitoring
with a scan rate of 0.8 second/scan or better.
7.2 Sampling system - capable of accurately and precisely sampling
100-2000 mL/minute of ambient air. (See Figure 1.) The dry
test meter may not be accurate at flows below 500 mL/minute;
in such cases it should be replaced by recorded flow readings
at the start, finish, and hourly during the collection. See
Section 9.4.
7.3 Stopwatch.
7.4 Friction top metal can, e.g., one-gallon (paint can) - to hold
clean cartridges and samples.
7.5 Thermometer - to record ambient temperature.
7.6 Barometer (o'ptional).
7.7 Glass syringe - 5 mL with Luer* fitting.
7.8 Volumetric flasks -2 mL, 10 mL, and 100 mL.
7.9 Glass syringe - 10 uL for GC injection.
8. Reagents and Materials
8.1 Thermosorb/N - Available from Thermedics Inc., 470 Wildwood St.,
P.O.Box 2999, Woburn, Mass., 01888-1799, or equivalent.
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T07-4
8.2 Dichloromethane - Pesticide quality, or equivalent.
8.3 Helium - Ultrapure compressed gas (99.9999%).
8.4 Perfluorotributylamine (FC-43) - for GC/MS calibration.
8.5 Chemical Standards - NDMA solutions. Available from various
chemical supply houses. Caution: NDMA is a suspected human
carcinogen. Handle in accordance with OSHA regulations.
8.6 Granular activated charcoal - for preventing contamination of
cartridges during storage.
8.7 Glass jar, 4 oz - to hold cartridges.
8.8 Glass vial - 1 dram, with Teflon®-lined screw cap.
8.9 Luer® fittings - to connect cartridges to sampling system.
8.10 Acetone- Reagent grade.
9. Sampling
9.1 Cartridges (Thermosorb/N) are purchased prepacked from Thermedics
Inc. These cartridges are 1.5 cm ID x 2 cm long polyethylene
tubes with Luer®-type fittings on each end. The adsorbent is
held in place with 100-mesh stainless steel screens at each
end. The cartridges are used as received and are discarded
after use. At least one cartridge from each production lot
should be used as a blank to check for contamination. The
cartridges are stored in screw-capped glass jars (with Luer®
style caps), and placed in a charcoal-containing metal can when
not in use.
9.2 The sampling system may employ either a mass flow controller or
a dry test meter. (See Figure 1.) For purposes of discussion,
the following procedure assumes the use of a dry test meter.
9.3 Before sample collection, the entire assembly (including a
"dummy" sampling cartridge) is installed and the flow rate is
checked at a value near the desired rate. In general, flow
rates of 100-2000 mL/minute should be employed. The flow rate
should be adjusted so that no more than 300 L of air is col-
lected over the desired sampling period. Generally, calibra-
tion is accomplished using a soap bubble flow meter or
-------
T07-5
calibrated wet test meter connected to the flow exit, assuming
the system is sealed. ASTM Method 3686 describes an
appropriate calibration scheme not requiring a sealed flow
system downstream of the pump.
9.4 Ideally, a dry gas meter is included in the system to record
total flow. If a dry gas meter is not available, the operator
must measure and record the sampling flow rate at the
beginning and end of the sampling period to determine sample
volume. If the sampling period exceeds two hours, the flow
rate should be measured at intermediate points during the
sampling period. Ideally, a rotameter should be included to
allow observation of the flow rate without interruption of the
sampling process.
9.5 To collect an air sample, a new Thermosorb/N cartridge is
removed from the glass jar and connected to the sampling
system using a Luer® adapter fitting. The glass jar is sealed
for later use. The following parameters are recorded on the
data sheet (see Figure 2 for an example): date, sampling
location, time, ambient temperature, barometric pressure (if
available), relative humidity (if available), dry gas meter
reading (if appropriate), flow rate, rotameter setting,
cartridge batch number, and dry gas meter and pump
identification numbers.
9.6 The sampler is allowed to operate for the desired period,
with periodic recording of the variables listed above. The
total flow should not exceed 300 L.
9.7 At the end of the sampling period, the parameters listed in Section
9.5 are recorded and the sample flow is stopped. If a dry gas
meter is not used, the flow rate must be checked at the end of
the sampling interval. If the flow rates at the beginning and
end of the sampling period differ by more than 15%, the
sample should be marked as suspect.
9.8 Immediately after sampling, the cartridge is removed from
the sampling system, capped, and placed back in the 4-oz
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T07-6
glass jar. The jar is then capped, sealed with Teflon® tape,
and placed in a friction-top can containing 1-2 inches of
granular charcoal. The samples are stored in the can until
analysis.
9.9 If a dry gas meter or equivalent total flow indicator is not
used, the average sample flow rate must be calculated
according to the following equation:
where
QA * average flow rate (mL/minute).
Ql> Q2» ••••ON = fl°w rates determined at beginning,
end, and immediate points during
sampling.
N = number of points averaged.
9.10 The total flow is then calculated using the following
equation:
1000
where
Vm = total sample volume (L) at measured
temperature and pressure.
T£ = stop time.
TI = start time.
T£-TI = sampling time (minutes).
-------
T07-7
9.11 The total volume (Vs) at standard conditions, 25°C and 760
mm Hg, is calculated from the following equation:
y PA y 298
u _ u X H X
vs m
760 273 + tA
where Vs = total sample volume (L) at standard
conditions of 25° C and 760 mm Hg.
Vm = total sample volume (L) at measured
temperature and pressure.
PA = average barometric pressure (mm Hg).
tA = average ambient temperature (°C).
10. Sample Desorption
10.1 Samples are returned to the laboratory and prepared for
analysis within one week of collection.
10.2 Using a glass syringe, the samples are pre-eluted to remove
potential interferences by passing 5 mL of dichloromethane
through the cartridge, in the same direction as sample flow.
This operation should be conducted over approximately a 2-minute
period. Excess solvent is expelled by injecting 5 mL of air
through the cartridge, again using the glass syringe.
10.3 The NDMA is then desorbed passing 2 mL of acetone through the
cartridge, in the direction opposite to sample flow, using a
glass syringe. A flow rate of approximately 0.5 mL/minute
is employed and the eluate is collected in a 2-mL volumetric
flask.
10.4 Desorption is halted once the volumetric flask is filled to
the mark. The sample is then transferred to a 1-dram vial
having a Teflon®-lined screw cap and refrigerated until
analysis. The vial is wrapped with aluminum foil to prevent
photolytic decomposition of the NDMA.
-------
T07-8
11. GC/MS Analysis
Although a variety of GC detectors can be used for NDMA determination,
the following procedure assumes the use of GC/MS in the selected ion
monitoring (SIM) mode.
11.1 Instrument Setup
11.1.1 Considerable variation in instrument configuration
is expected from one laboratory to another. There-
fore, each laboratory must be responsible for veri-
fying that its particular system yields satisfactory
results. The GC/MS system must be capable of accom-
modating a fused-silica capillary column, which can be
inserted directly into the ion source. The system must
be capable of acquiring and processing data in the
selected ion monitoring mode.
11.1.2 Although alternative column systems can be used, a
0.2 mm I.D. x 50 m Carbowax 20M fused-silica column
(Hewlett-Packard Part No. 19091-60150, or equivalent)
is recommended. After installation, a helium carrier
gas flow of 2 ml per minute is established and the
column is conditioned at 250°C for 16 hours. The
injector and GC/MS transfer line temperatures should
also be set at 250°C.
11.1.3 The MS and data system are set up according to manu-
facturer's specifications. Electron impact ionization
(70 eV) should be employed. Once the entire GC/MS
system is set up, it is calibrated as described in
Section 11.2. The user should prepare a detailed
standard operating procedure (SOP) describing this
process for the particular instrument being used.
-------
T07-9
11.2 Instrument Calibration
11.2.1 Tuning and mass standardization of the MS system is
performed according to manufacturer's instructions
and relevant information from the user-prepared SOP.
Perfluorotributyl amine should generally be employed
for this purpose. The material is introduced
directly into the ion source through a molecular
leak. The instrumental parameters (e.g., lens,
voltages, resolution, etc.) should be adjusted to
give the relative ion abundances shown in Table 1 as
well as acceptable resolution and peak shape. If
these approximate relative abundances cannot be
achieved, the ion source may require cleaning
according to manufacturer's instructions. In the
event that the user's instrument cannot achieve these
relative ion abundances, but is otherwise operating
properly, the user may adopt another set of relative
abundances as performance criteria. However, these
values must be repeatable on a day-to-day basis.
11.2.2 After the mass standardization and tuning process has
been completed and the appropriate values entered
into the data system, the user should set the SIM
monitoring parameters (i.e., mass centroid and window
to be monitored) by injecting a moderatley high level
standard solution (100 ug/mL) of NDMA onto the 6C/MS in
the full scan mode. The scan range should be 40 to 200
amu at a rate of 0.5 to 0.8 scans/second. The nominal
mass 42, 43, and 74 amu ions are to be used for SIM
monitoring, with the 74 amu ion employed for NDMA quan-
tification.
-------
T07-10
11.2.3 Before injection of NDMA standards, the GC oven
temperature is stabilized at 45°C. The filament and
electron multiplier voltage are turned off. A 2-uL
aliquot of an appropriate NDMA standard, dissolved in
acetone, is injected onto the GC/MS system using the
splitless injection technique. Concentrated NDMA
standards can be purchased from chemical supply
houses. The standards are diluted to the appropriate
concentration with acetone. CAUTION: NDMA is a
suspected carcinogen and must be handled according to
OSHA regulations. After five minutes, the electron
multiplier and filament are turned on, data acquisition
is initiated, and the oven temperature is programmed
to 250°C at a rate of 16°C/minute. After elution of
the NDMA peak from the GC/MS (Figure 3), the data
acquisition process can be halted and data processing
initiated.
11.2.4 Once the appropriate SIM parameters have been estab-
lished, as described in Section 11.2.2, the instrument
is calibrated by analyzing a range of NDMA standards
using the SIM prodecure. If necessary, the electron
multiplier voltage or amplifier gain can be adjusted
to give the desired sensitivity for standards
bracketing the range of interest. A calibration
curve of m/e 74 ion intensity versus quantity of NDMA
injected is constructed and used to calculate NDMA
concentration in the samples.
11.3 Sample Analysis
11.3.1 The sample analysis process is the same as that de-
scribed in Section 11.2.3 for calibration standards.
Samples should be handled so as to minimize exposure
to light.
-------
T07-11
11.3.2 If a peak is observed for NDMA (within ±6 seconds of
the expected retention time), the areas (integrated
ion intensities) for m/e 42, 43, and 74 are
calculated. The area of the m/e 74 peak is used to
calculate NDMA concentration. The ratios of
m/e 42/74 and 43/74 ion intensities are used to
determine the certainty of the NDMA identification.
Ideally, these ratios should be within ±20% of the
ratios for an NDMA standard in order to have
confidence in the peak identification. Figure 4
illustrates the MS scan for N-nitrosodimethylamine.
12. Calculations
12.1 Calibration Response Factors
12.1.1 Data from calibration standards are used to calculate
a response factor for NDMA. Ideally, the process
involves analysis of at least three calibration
levels of NDMA during a given day and determination
of the response factor (area/ng injected) from the
linear least squares fit of a plot of nanograms in-
jected versus area (for the m/e 74 ion). In general,
quantities of NDMA greater than 1000 nanograms should
not be injected because of column overloading and/or
MS response nonlinearity.
12.1.2 If substantial nonlinearity is present in the cali-
bration curve, a nonlinear least squares fit (e.g.,
quadratic) should be employed. This process involves
fitting the data to the following equation:
Y = A + BX + CX2
-------
T07-12
where
Y = peak area
X « quantity of NDMA (ng)
A. B, and C are coefficients in the equation
12.2 NDMA Concentration
12.2.1 Analyte quantities on a sample cartridge are
calculated from the following equation:
where
= A + BXA + CXA2
YA is the area of the m/e 74 ion for the sample
injection.
XA is the calculated quantity of NDMA (ng) on the
sample cartridge.
A, B, and C are the coefficients calculated from the
calibration curve described in Section 12.1.2.
12.2.2 If instrumental response is essentially linear over
the concentration range of interest, a linear equation
(C=0 in the equation above) can be employed.
12.2.3 Concentration of analyte in the original air sample
is calculated from the following equation:
C
where
CA is the calculated concentration of analyte (ng/L).
Vs and XA are as previously defined in Sections 9.11
and 12.2.1, respectively.
-------
T07-13
13. Performance Criteria and Quality Assurance
This section summarizes required quality assurance (QA) measures and
provides guidance concerning performance criteria that should be
achieved within each laboratory.
13.1 Standard Operating Procedures (SOPs).
13.1.1 User should generate SOPs describing the
following activites in their laboratory:
1) assembly, calibration, and operation
of the sampling system with make and model of
equipment used; 2) preparation, purification,
storage, and handling of Thermosorb/N cartridges
and samples; 3) assembly, calibration, and operation
of the GC/MS system with make and model of equipment
used; and 4) all aspects of data recording and
processing, including lists of computer hardware
and software used.
13.1.2 SOPs should provide specific stepwise instructions
and should be readily available to and understood
by the laboratory personnel conducting the work.
13.2 Sample Collection
13.2.1 During each sampling event, at least one clean
cartridge will accompany the samples to the field and
back to the laboratory, having been placed in the
sampler but without sampling air, to serve as a field
blank. The average amount of material found on the
field blank cartridges may be subtracted from the
amount found on the actual samples. However, if the
blank level is greater than 25% of the sample amount,
data for that component must be identified as suspect
13.2.2 During each sampling event, at least one set of
parallel samples (two or more samples collected
simultaneously) should be collected. If agreement
-------
T07-14
between parallel samples is not generally within
+25%, the user should collect parallel samples on a
much more frequent basis (perhaps for all sampling
points;.
13.2.3 Backup cartridges (two cartridges in series) should
be collected with each sampling event. Backup car-
tridges should contain less than 10% of the amount
of NDMA found- in the front cartridges, or be equiva-
lent to the blank cartridge level, whichever is
greater.
13.2.4 NDMA recovery for spiked cartridges (using a solution-
spiking technique) should be determined before initial
use of the method on real samples. Currently available
information indicates that a recovery of 75% or greater
should be achieved.
13.3 GC/MS Analysis
13.3.1 Performance criteria for MS tuning and mass standard-
ization are discussed in Section 11.2 and Table 1.
Additional criteria can be used by the laboratory, if
desired. The following sections provide performance
guidance and suggested criteria for determining the
acceptability of the GC/MS system.
13.3.2 Chromatographic efficiency should be evaluated daily
by the injection of NDMA calibration standards. The
NDMA peak should be plotted on an expanded time scale
so that its width at 10% of the peak height can be
calculated, as shown in Figure 5. The width of the
peak at 10% height should not exceed 10 seconds. More
stringent criteria may be required for certain appli-
cations. The asymmetry factor (see Figure 5) should
be between 0.8 and 2.0.
-------
T07-15
13.3.3 The detection limit for NDMA is calculated from the
data obtained for calibration standards. The
detection limit is defined as
DL = A + 3.3S
where
DL is the calculated detection limit in nanograms
injected.
A is the intercept calculated in Section 12.1.2.
S is the standard deviation of replicate determina-
tions of the lowest-level standard (at least three
such determinations are required). The lowest-level
standard should yield a signal-to-noise ratio (from
the total ion current response) of approximately 5.
13.3.4 Replicate GC/MS analysis of NDMA standards and/or
sample extracts should be conducted on a daily basis.
A precision of +15% RSD.or better should be achieved.
-------
T07-16
REFERENCES
(1) Marano, R. S., Updegrove, W. S.. and Machem, R. C., "Determination
of Trace Levels of Nitrosamines in Air by Gas Chromatography/Low
Resolution Mass Spectrometry," Anal. Chem., 54, 1947-1951 (1982).
(2) Fine, D. H., et. al, "N-Nitrosodimethylamine in Air," Bull. Env.
Cont. Toxicol., 1J5, 739-746 (1976).
(3) "EPA Method 607 - Nitrosamines," Federal Register, 49, 43313-43319.
October 26, 1984. ~
(4) Anderson, R. J., "Nitrogen-Selective Detection in Gas Chromatography,"
Tracer Inc. Applications Note 79-3, Austin, Texas.
(5) Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis,"
American Society for Testing and Materials, Philadelphia, Pennsylvania,
(6) Riggin, R. M., "Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds in Ambient Air," EPA-600/4-83-
027, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina, 1983.
-------
T07-17
MASS FLOW
CONTROLLERS
OILLESS
PUMP
VENT
Coupling to
connect
Thermosorb® N
Adsorbent Cartridges
(a) MASS FLOW CONTROL
ROTAMETER
DRY
TEST
METER
"**
1
PUMP
iv
^
1*1
1 1
IEEDLE
yALVE
VENT
(DRY TEST METER SHOULD NOT BE USED
FOR FLOW OF LESS THAN 500 ml/mmut«)
(b) NEEDLE VALVE/DRY TEST METER
coupling to
connect
Thermosorb® N
adsorbent
cartridge
FIGURE 1. TYPICAL SAMPLING SYSTEM CONFIGURATION
-------
PROJECT:
SITE:
LOCATION:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
T07-18
SAMPLING DATA SHEET
(One Sample per Data Sheet)
DATES(S) SAMPLED:
TIME PERIOD SAMPLED:
OPERATOR:
CALIBRATED BY:
Sample Number:
Start Time:
Stop Time:
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading,
or
„___ _ 1
lOuu * (Sampling Time in Minutes)
L
L
* Flow rate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
FIGURE 2. EXAMPLE SAMPLING DATA SHEET
-------
_ _. m
«£»
m
TOTAL ION CURRENT
CJI O
,«
C/) m
> Z
-
go
^2
S>
O H
SO
> Q
r\>
m
— o»
o>
NDEA
NOPA
RESIDUAL SOLVENT
NDBA
O m
cn
-------
C2H6N20
Methanamme, N— methyl—N— nitroso—
Me 2 NNO
100.
80-
60-
40-
20-
10 20 30 40 50 60 70
80 9
30
FIGURE 4. MASS SPECTROSCOPY SCAN (10 TO 150 AMV)
OF NDMA AT A RATE OF 0.5 TO 0.8 SCANS/SECOND
-------
T07-21
Asymmetry Factor
BC
Exampte Calculation:
Peak Height - DE = 100 mm
10% Peak Height = BD = 10 mm
Peak Width at 10% Peak Height - AC
AB = 11 mm
BC = 12 mm
23 mm
12
Therefore: Asymmetry Factor = —
,
1.
FIGURE 5. PEAK ASYMMETRY CALCULATION
-------
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-------
Revision 1.0
September, 1986
METHOD T08
METHOD FOR THE DETERMINATION OF PHENOL
AND METHYLPHENOLS (CRESOLS) IN AMBIENT AIR USING
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
1. Scope
1.1 This document describes a method for determination of phenol
and methylphenols (cresols) in ambient air. With careful
attention to reagent purity and other factors, the method
can detect these compounds at the 1-5 ppbv level.
1.2 The method as written has not been rigorously evaluated. The
approach is a composite of several existing methods (1-3).
The choice of HPLC detection system will be dependent on the
requirements of the individual user. However, the UV detection
procedure is considered to be most generally useful for
relatively clean samples.
2. Applicable Documents
2.1 ASTM Standards
D1356 - Definitions of Terms Related to Atmospheric Sampling
and Analysis(4).
2.2 Other Documents
U.S. EPA Technical Assistance Document (5).
3. Summary of Method
3.1 Ambient air is drawn through two midget impingers, each con-
taining 15 mL of 0.1 N NaOH. The phenols are trapped as
phenolates.
3.2 The impinger solutions are placed in a vial with a Teflon®-
lined screw cap and returned to the laboratory for
-------
T08-2
analysis. The solution is cooled in an ice bath and adjusted
to pH <4 by addition of 1 ml of 5% v/v sulfuric acid. The sample
is adjusted to a final volume of 25 mL with distilled water.
3.3 The phenols are determined using reverse-phase HPLC with
either ultraviolet (UV) absorption detection at 274 nm,
electrochemical detection, or fluorescence detection. In
general, the UV detection approach should be used for
relatively clean samples.
4. Significance
4.1 Phenols are emitted into the atmosphere from chemical opera-
tions and various combustion sources. Many of these compounds
are acutely toxic, and their determination in ambient air is
required in order to assess human health impacts.
4.2 Conventional methods for phenols have generally employed
colorimetric or gas chromatographic techniques with relatively
large detection limits. The method described here reduces
the detection limit through use of HPLC.
5. Definitions
Definitions used in this document and in any user-prepared Standard
Operating Procedures (SOPs) should be consistent with ASTM D1356
(5). All abbreviations and symbols are defined within this document
at the point of use.
6. Interferences
6.1 Compounds having the same retention times as the compounds of
interest will interfere in the method. Such interferences can
often be overcome by altering the separation conditions (e.g.,
using alternative HPLC columns or mobile phase compositions) or
detectors. Additionally, the phenolic compounds of interest
in this method may be oxidized during sampling. Validation
experiments may be required to show that the four target
compounds are not substantially degraded.
-------
T08-3
6.2 If interferences are suspected in a "dirty" sample, prelimi-
nary cleanup steps may be required to identify interfering
compounds by recording infrared spectrophotometry followed
by specific ion-exchange column chromatography. Likewise,
overlapping HPLC peaks may be resolved by increasing/decreasing
component concentration of the mobile phase.
6.3 All reagents must be checked for contamination before use.
7. Apparatus
7.1 Isocratic HPLC system consisting of a mobile-phase reservoir,
a high-pressure pump, an injection valve, a Zorbax ODS or
C-18 reverse-phase column, or equivalent (25 cm x 4.6 mm ID),
a variable-wavelength UV detector operating at 274 nm, and a
data system or strip-chart recorder (Figure 1). Amperometric
(electrochemical) or fluorescence detectors may also be employed.
7.2 Sampling system - capable of accurately and precisely sampling
100-1000 mL/minute of ambient air (Figure 2).
7.3 Stopwatch.
7.4 Friction-top metal can, e.g., one-gallon (paint can) - to hold
samples.
7.5 Thermometer - to record ambient temperature.
7.6 Barometer (optional).
7.7 Analytical balance - 0.1 mg sensitivity.
7.8 Midget impingers --jet inlet type, 25-mL.
7.9 Suction filtration apparatus - for filtering HPLC mobile phase.
7.10 Volumetric flasks - 100 mL and 500 mL.
7.11 Pipettes - various sizes, 1-10 mL.
7.12 Helium purge line (optional) - for degassing HPLC mobile phase.
7.13 Erlenmeyer flask, 1 L - for preparing HPLC mobile phase.
7.14 Graduated cylinder, 1 L - for preparing HPLC mobile phase.
7.15 Microliter syringe, 100-250 uL - for HPLC injection.
8. Reagents and Materials
8.1 Bottles, 10 oz, glass, with Teflon®-lined screw cap - for
storing sampling reagent.
8.2 Vials, 25 mL, with Teflon®-lined screw cap - for holding samples.
-------
T08-4
8.3 Disposable pipettes and bulbs.
8.4 Granular charcoal.
8.5 Methanol - distilled in glass or pesticide grade.
8.6 Sodium hydroxide - analytical reagent grade.
8.7 Sulfuric acid - analytical reagent grade.
8.8 Reagent water - purified by ion exchange and carbon
filtration, or distillation.
8.9 Polyester filters, 0.22 urn - Nuclepore, or equivalent.
8.10 Phenol, 2-methyl-, 3-methyl-, and 4-methylphenol - neat
standards (99+ % purity) for instrument calibration.
8.11 Sampling reagent, 0.1 N NaOH. Dissolve 4.0 grams of NaOH in
reagent water and dilute to a final volume of 1 L. Store
In a glass bottle with Teflon®-lined cap.
8.12 Sulfuric acid, 5% v/v. Slowly add 5 mL of concentrated
sulfuric acid to 95 mL of reagent water.
8.13 Acetate buffer, 0.1M, pH 4.8 - Dissolve 5.8 ml of glacial
acetic acid and 13.6 grams of sodium acetate trihydrate in 1 L
of reagent water.
8.14 Acetom'trile - spectroscopic grade.
8.15 Glacial acetic acid - analytical reagent grade.
8.16 Sodium acetate trihydrate - analytical reagent grade.
9. Sampling
9.1 The sampling apparatus is assembled and should be similar to
that shown in Figure 2. EPA Federal Reference Method 6 uses
essentially the same sampling system (6). All glassware
(e.g., impingers, sampling bottles, etc.) must be thoroughly
rinsed with methanol and oven-dried before use.
9.2 Before sample collection, the entire assembly (including
, empty sample impingers) is installed and the flow rate checked
at a value near the desired rate. In general, flow rates of
100-1000 mL/minute are useful. Flow rates greater than
1000 mL/minute should not be used because impinger collection
-------
T08-5
efficiency may decrease. Generally, calibration is accomp-
lished using a soap bubble flow meter or calibrated wet test
meter connected to the flow exit, assuming the entire system
is sealed. ASTM Method D3686 describes an appropriate
calibration scheme that does not require a sealed-flow system
downstream of the pump (4).
9.3 Ideally, a dry gas meter is included in the system to record
total flow, if the flow rate is sufficient for its use. If a
dry gas meter is not available, the operator must measure and
record the sampling flow rate at the beginning and end of the
sampling period to determine sample volume. If the sampling
time exceeds two hours, the flow rate should be measured at
intermediate points during the sampling period. Ideally, a
rotameter should be included to allow observation of the flow
rate without interruption of the sampling process.
9.4 To collect an air sample, two clean midget impingers are
loaded with 15 mL of 0.1 N NaOH each and sample flow is start-
ed. The following parameters are recorded on the data sheet
(see Figure 3 for an example): date, sampling location, time,
ambient temperature, barometric pressure (if available),
relative humidity (if available), dry gas meter reading (if
appropriate), flow rate, rotameter setting, 0.1 N NaOH reagent
batch number, and dry gas meter and pump identification
numbers.
9.5 The sampler is allowed to operate for the desired period, with
periodic recording of the variables listed above. The total
volume should not exceed 80 L. The operator must ensure that
at least 5 ml of reagent remains in the impinger at the end of
the sampling interval. (Note; for high ambient temperatures,
lower sampling volumes may be required.)
9.6 At the end of the sampling period, the parameters listed in Sec-
tion 9.4 are recorded and the sample flow is stopped. If a dry
gas meter is not used, the flow rate must be checked at the end
of the sampling interval. If the flow rates at the beginning and
-------
T08-6
end of the sampling period differ by more than 15%, the sample
should be discarded.
9.7 Immediately after sampling, the impinger is removed from the
sampling system. The contents of the impinger are emptied
into a clean 25-mL glass vial with a Teflon®-lined screw-
cap. The impinger is then rinsed with 5 ml of reagent water
and the rinse solution is added to the vial. The vial is then
capped, sealed with Teflon® tape, and placed in a friction-top
can containing 1-2 inches of granular charcoal. The samples
are stored in the can and refrigerated until analysis. No
degradation has been observed if the time between refrigration
and analysis is less than 48 hours.
9.8 If a dry gas meter or equivalent total flow indicator is not
used, the average sample flow rate must be calculated
according to the following equation:
where
QA = average flow rate (ml/mlnute).
Ql, 0.2, QN = flow rates determined at beginning, end, and
intermediate points during sampling.
N = number of points averaged.
9.9 The total flow is then calculated using the following
equation:
(T2-T ) * o
-------
T08-7
where
Vm = total volume (L) sampled at measured
temperature and pressure.
?2 = stop time.
TI = start time.
T2"Tl = total sampling time (minutes).
QA = average flow rate (ml/minute).
9.10 The volume of air sampled is often reported unconnected for
atmospheric conditions (i.e., under ambient conditions).
However, the value should be adjusted to standard conditions
(25°C and 760 mm pressure) using the following equation:
x PA
u _ u X H
vs m
760 273 + TA
where
Vs = total sample volume (L) at 25°C and 760 mm Hg
pressure.
Vm = total sample volume (L) under ambient conditions.
Calculated as in Section 9.9 or from dry gas
meter reading.
P/\ = ambient pressure (mm Hg).
TA = ambient temperature (°C).
10. Sample Analysis
10.1 Sample Preparation
10.1.1 The samples are returned to the laboratory in 25-mL
screw-capped vials. The contents of each vial are
transferred to a 25-mL volumetric flask. A 1-mL
volume of 5% sulfuric acid is added and the final
volume is adjusted to 25 ml with reagent water.
-------
T08-8
10.1.2 The solution is thoroughly mixed and then placed in a
25-ml screw-capped vial for storage (refrigerated)
until HPLC analysis.
10.2 HPLC Analysis
10.2.1 The HPLC system is assembled and calibrated as described
in Section 11. The operating parameters are as follows:
Column: C-18 RP
Mobile Phase: 30% acetonitrile/70% acetate
buffer solution
Detector: ultraviolet, operating at
274 nm
Flow Rate: 0.3 mL/minute
Retention Time: phenol - 9.4 minutes
o-cresol - 12.5 minutes
m-cresol - 11.5 minutes Individual
p-cresol - 11.9 minutes
phenol - 9.4 minutes
o-cresol - 12.8 minutes Combined
m/p-cresol - 11.9 minutes
Before each analysis, the detector baseline is checked
to ensure stable operation.
10.2.2 A 100-uL aliquot of the sample is drawn into a clean
HPLC injection syringe. The sample injection loop
(50 uL) is loaded and an injection is made. The data
system, if available, is activated simultaneously with
the injection and the point of injection is marked on
the strip-chart recorder.
- 10.2.3 After approximately one minute, the injection valve
is returned to the "load" position and the syringe and
valve are flushed with water in preparation for
the next sample analysis.
10.2.4 After elution of the last component of interest, data
acquisition is terminated and the component concen-
trations are calculated as described in Section 12.
-------
T08-9
10.2.5 Phenols have been successfully separated from cresols
utilizing HPLC with the above operating parameters.
However, meta- and para-cresols have not been successfully
separated. Figure 4 illustrates a typical chromatogram.
10.2.6 After a stable baseline is achieved, the system can
be used for further sample analyses as described
above.
10.2.7 If the concentration of analyte exceeds the linear
range of the instrument, the sample should be diluted
with mobile phase, or a smaller volume can be injected
into the HPLC.
10.2.8 If the retention time is not duplicated, as determined
by the calibration curve, you may increase or decrease
the acetonitrile/water ratio to obtain the correct elution
time, as specified in Figure 4. If the elution time is
long, increase the ratio; if it is too short, decrease
the ratio.
11.0 HPLC Assembly and Calibration
11.1 The HPLC system is assembled and operated according to
Section 10.2.1.
11.2 The HPLC mobile phase is prepared by mixing 300 mL of acetonitrile
and 750 mL of acetate buffer, pH 4.8. This mixture is filtered
through a 0.22-um polyester membrane filter in an all-glass
and Teflon® suction filtration apparatus. The filtered mobile
phase is degassed by purging with helium for 10-15 minutes
(100 mL/minute) or by heating to 60°C for 5-10 minutes in an
Erlenmeyer flask covered with a watch glass. A constant back
pressure restrictor (50 psi) or short length (6-12 inches) of
0.01-inch I.D. Teflon® tubing should be placed after the
detector to eliminate further mobile phase outgassing.
-------
T08-10
11.3 The mobile phase is placed in the HPLC solvent reservoir and
the pump is set at a flow rate of 0.3 mL/minute and allowed
to pump for 20-30 minutes before the first analysis. The
detector is switched on at least 30 minutes before the first
analysis and the detector output is displayed on a strip-chart
recorder or similar output device. UV detection at 274 nm is
generally preferred. Alternatively, fluorescence detection
with 274-nm excitation at 298-nm emission (2), or electrochemi-
cal detection at 0.9 volts (glassy carbon electrode versus
Ag/AgCl) (3) may be used. Once a stable baseline is achieved,
the system is ready for calibration.
11.4 Calibration standards are prepared in HPLC mobile phase from the
neat materials. Individual stock solutions of 100 mg/L are
prepared by dissolving 10 mg of solid derivative in 100 mL of
mobile phase. These individual solutions are used to prepare
calibration standards containing all of the phenols and cresols
of interest at concentrations spanning the range of interest.
11.5 Each calibration standard (at least five levels) is analyzed three
times and area response is tabulated against mass injected.
Figures 5a through 5e illustrate HPLC response to various phenol
concentrations (1 mL/minute flow rate). All calibration runs
are performed as described for sample analyses in Section 10.
Using the UV detector, a linear response range of approximately
0.05 to 10 mg/L should be achieved for 50-uL injection volumes.
The results may be used to prepare a calibration curve, as
illustrated in Figure 6 for phenols. Linear response is
indicated where a correlation coefficient of at least 0.999
for a linear least-squares fit of the data (concentration
versus area response) is obtained. The retention times for
each analyte should agree within 2%.
11.6 Once linear response has been documented, an intermediate con-
centration standard near the anticipated levels for each compo-
nent, but at least 10 times the detection limit, should be chosen
for daily calibration. The response for the various components
should be within 10% day to day. If greater variability is
observed, recalibration may be required or a new calibration
curve must be developed from fresh standards.
-------
T08-11
11 7 The response for each exponent In the daily calibration standard
is used to calculate a response factor according to the following
equation:
C x
RFC =
RC
where
RFC - response factor (usually area counts) for the
component of interest in nanograms injected/response
unit.
Cc - concentration (mg/L) of analyte in the daily call-
bration standard.
V, = volume (uL) of calibration standard injected.
R^ . response (area counts) for analyte in the calibration
standard.
12. Calculations
12.1 The concentration of each compound is calculated for each
sample using the following equation:
WH - RFC X Rd X !£ X ^
d c d Vj VA
where
Wd = total quantity of analyte (ug) in the sample.
RFC = response factor calculated in Section 11.6.
Rd = response (area counts or other response units)
for analyte in sample extract.
VE = final volume (ml) of sample extract.
Vl = volume of extract (uL) injected onto the HPLC
system.
VD = redilution volume (if sample was rediluted).
VA = aliquot used for redilution (if sample was
rediluted).
-------
T08-12
12.2 The concentration of analyte in the original sample is
calculated from the following equation:
CA = d x 1000
vm (or Vs)
where
CA = concentration of analyte (ng/L) in the original sample.
Wjj = total quantity of analyte (ug) in sample.
Vm = total sample volume (L) under ambient conditions.
Vs = total sample volume (L) at 25 °C and 760 mm Hg.
12.3 The analyte concentrations can be converted to ppbv using the
following equation:
CA (ppbv) * CA (ng/L) x 24.4
MWA
where
CA (ng/L) is calculated using Vs.
MWA = molecular weight of analyte.
13. Performance Criteria and Quality Assurance
This section summarizes required quality assurance (QA) measures and
provides guidance concerning performance criteria that should be
achieved within each laboratory.
1.3.1 Standard Operating Procedures (SOPs).
13.1.1 Users should generate SOPs describing the following
activities in their laboratory: (1) assembly,
calibration, and operation of the sampling system,
with make and model of equipment used; (2) prepara-
tion, purification, storage, and handling of sampl-
ing reagent and samples; (3) assembly, calibration,
-------
T08-13
and operation of the HPLC system, with make and model
of equipment used; and (4) all aspects of data recording
and processing, including lists of computer hardware
and software used.
13.1.2 SOPs should provide specific stepwise instructions
and should be readily available to and understood
by the laboratory personnel conducting the work.
13.2 HPLC System Performance
13.2.1 The general appearance of the HPLC chromatogram should
be similar to that illustrated in Figure 4.
13.2.2 The HPLC system efficiency and peak asymmetry factor
should be determined in the following manner: A
solution of phenol corresponding to at least 20 times
the detection limit should be injected with the re-
corder chart sensitivity and speed set to yield a peak
approximately 75% of full scale and 1 cm wide at half
height. The peak asymmetry factor is determined as
shown in Figure 7, and should be betweeen 0.8 and 1.8.
13.2.3 HPLC system efficiency is calculated according to the
following equation:
N = 5.54
where
N = column efficiency (theoretical plates).
tr = retention time (seconds) of analyte.
wl/2 = widtn of component peak at half height
(seconds).
A column efficiency of >5,000 theoretical plates
should be obtained.
13.2.4 Precision of response for replicate HPLC injections
should be +10% or less, day to day, for calibration
standards. Precision of retention times should be
+2%, on a given day.
-------
T08-14
13.3 Process Blanks
13.3.1 Before use, a 15-mL aliquot of each batch of 0.1 N
NaOH reagent should be analyzed as described in
Section 10. In general, analyte levels equivalent to
<5 ng/L in an 80-L sample should be achieved.
13.3.2 At least one field blank, or 10% of the field samples,
whichever is larger, should be shipped and analyzed
with each group of samples. The number of samples
within a group and/or time frame should be recorded
so that a specified percentage of blanks is obtained
for a given number of field samples. The field blank
is treated identically to the samples except that no
air is drawn through the reagent. The same performance
criteria described in Section 13.3.1 should be met for
process blanks.
13.4 Method Precision and Accuracy
13.4.1 At least one duplicate sample, or 10% of the field
samples, whichever is larger, should be collected
during each sampling episode. Precision for field
replication should be ±20% or better.
13.4.2 Precision for replicate HPLC injections should be
_+10% or better, day to day, for calibration
standards.
13.4.3 At least one spiked sample, or 10% of the field
samples, whichever is larger, should be collected.
The impinger solution is spiked with a known quantity
of the compound of interest, prepared as a dilute
water solution. A recovery of >80% should be achieved
routinely.
13.4.4 Before initial use of the method, each laboratory
should generate triplicate spiked samples at a
minimum of three concentration levels, bracketing the
range of interest for each compound. Triplicate
nonspiked samples must also be processed. Spike
recoveries of >80 ±10% and blank levels of <5 ng/L
(using an 80-L sampling volume) should be achieved.
-------
T08-15
REFERENCES
(1) NIOSH P & CAM Method S330-1, "Phenol," National Institute of
Occupational Safety and Health, Methods Manual, Vol. 3, 1978.
(2) Ogan, K. and, Katz, E.. "Liquid Chromatographic Separation of
Alkylphenols with Fluorescence and Ultraviolet Detection," Anal.
Chem., E.3, 160-163 (1981).
(3) Shoup, R. E.f and Mayer, G. S., "Determination of Environmental
Phenols by Liquid Chromatography Electrochemistry," Anal. Chem.,
54, 1164-1169 (1982).
(4) Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis,"
American Society for Testing and Materials, Philadelphia,
Pennsylvania, 1983.
(5) Riggin, R. M., "Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds in Ambient Air," EPA-600/4-83-
027, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina, 1983.
(6) "Method 6 Determination of S02 Emissions from Stationary Sources,"
Federal Register, Vol. 42.. No. 160. August, 1977.
-------
INJECTION
VALVE
MOBILE
PHASE
RESERVOIR
COLUMN
VARIABLE
WAVELENGTH
UV
DETECTOR
TO
WASTE
DATA
SYSTEM
STRIPCHART
RECORDER
o
oo
Cfi
FIGURE 1. TYPICAL HPLC SYSTEM
-------
SILICA GEL
SAMPLE
IMPINGERS
ROTAMETER
VENT
DRY
TEST
METER
PUMP
0.1 N NaOH
o
00
I
FIGURE 2. TYPICAL SAMPLING SYSTEM FOR MONITORING
PHENOLS/CRESOLS IN AMBIENT AIR
-------
T08-18
PROJECT:
SITE:
LOCATION:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
SAMPLING DATA SHEET
(One Sample per Data Sheet)
DATES(S) SAMPLED:
TIME PERIOD SAMPLED:
OPERATOR:
CALIBRATED BY:
Sample Number:
Start Time:
Stop Time:
Time
1.
2.
3.
4.
N.
Dry Gas
Meter
Reading
Rotameter
Reading
Flow
Rate,*0
mL/min
Ambient
Temperature
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
Q2 + Q3 "• 0N
_
1000 * (Sampling Time in Minutes)
* Flow rate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
FIGURE 3. EXAMPLE SAMPLING DATA SHEET
-------
T08-19
O
ro
OPERATING PARAMETERS
HPLC
Column: C-18 RP
Mobile Phase: 30% Acetonitrile/70% Acetate Buffer
Detector: Ultra violet operating at 274 nm
Flow Rate: 1 ml/min
Retention Time: 3.4 minutes
M/P-CRESOL-**
0-CRESOL
JUL. 30, 1986 15:07:17 CHART 0.50 CM/MIN
RUN *43 CALC fO
COLUMN SOLVENT OPR ID:
EXTERNAL STANDARD QUANTITATION
AMOUNT RT EXP RT
790.82600 8.81
2686.95000 11.30
1645.46000 12.22
5123.24000
AREA RF
790826 L O.OOOOOOEO
2686966 F O.OOOOOOEO
1645466 L O.OOOOOOEO
O
LU
TIME
FIGURE 4. TYPICAL CHROMATOGRAM ILLUSTRATING
SEPARATION OF PHENOLS/CRESOLS BY HPLC
-------
T08-20
(b)
3.43
(O
3.39
(a)
3.39
O
LJ
TIME
TIME-
(d)
3.44
(VI
cvi
(e)
3.39
CONC.
AREA
COUNTS
249054
554609
804918
1038422
1296781
u
UJ
TIME
4/tg
TIME
FIGURE 5a-5e. HPLC CHROMATOGRAM OF VARYING
PHENOL CONCENTRATIONS
-------
T08-21
o
o
10
Column: C-18 RP
Mobile Phase: 30% Acetonitrile/70% Acetate Buffer
Detector: Ultra violet operating at 274 nm
Flow Rate: 1 ml/min
Retention Time: 3.4 minutes
D
O
O
O
O
o
LU
DC
o
o
ID
CORRELATION COEFFICIENT:
0.999
T
2
3 4
PHENOL (pg)
FIGURE 6. CALIBRATION CURVE FOR PHENOL
-------
T08-22
Asymmetry Factor
BC
AS
Example Calculation:
Peak Haight « DE » 100 mm
10% Paak Height • SO » 10 mm
Peak Width at 10% Peak Height - AC
AB * 11 mm
BC « 12 mm
23 mm
Therefore: Asymmetry Factor * ~
1.1
FIGURE 7. PEAK ASYMMETRY CALCULATION
-------
Revision 1.1
June, 1988
METHOD T09
METHOD FOR THE DETERMINATION OF POLYCHLORINATED DIBENZO-
p D OXINS (PCDDs) IN AMBIENT AIR USING HIGH-RESOLUTION GAS
CHROMATOGRAPHY/HIGH-RESOLUTION MASS SPECTROMETRY (HRGC/HRMS)
1. Scope
1.1 This document describes a method for the determination of
polychlorinated dibenzo-p-dioxins (PCDDs) in ambient air. In
particular, the following PCDDs have been evaluated in the
laboratory utilizing this method:
o l,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD)
o l,2,3,4,7,8-hexachlorodibenzo-p-dioxin (1,2,3,4,7,8-HXCDD)
o Octachlorodibenzo-p-dioxin (OCDD)
o 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)
The method consists of sampling ambient air via an inlet filter
followed by a cartridge (filled with polyurethane foam) and
analysis of the sample using high-resolution gas chromatography/
high-resolution mass spectrometry (HRGC/HRMS). Original laboratory
studies have indicated that the use of polyurethane foam (PUF) or
silica gel in the sampler will give equal efficiencies for retain-
ing PCDD/PCDF isomers; i.e., the median retention efficiencies
for the PCDD isomers ranged from 67 to 124 percent with PUF and
from 47 to 133 percent with silica gel. Silica gel, however,
produced lower levels of background interferences than PUF.
The detection limits were, therefore, approximately four times
lower for tetrachlorinated isomers and ten times lower for
hexachlorinated isomers when using silica gel as the adsorbent.
The difference in detection limit was approximately a factor of
two for the octachlorinated isomers. However, due to variable
recovery and extensive cleanup required with silica gel, the
method has been written using PUF as the adsorbent.
1.2 With careful attention to reagent purity and other factors, the
method can detect PCDDs in filtered air at levels below 1-5 pg/m3*.
*Lowest levels for which the method has been validated. Up to en order of magnitude better
sensitivity should be achievable with 24-hour air samples.
-------
T09-2
1.3 Average recoveries ranged from 68 percent to 140 percent in
laboratory evaluations of the method sampling ultrapure filtered
air. Percentage recoveries and sensitivities obtainable for
ambient air samples have not been determined.
Applicable Documents
2.1 ASTM Standards
2.1.1 Method D1356 - Definitions of Terms Relating to Atmospheric
Sampling and Analysis.
2.1.2 Method E260 - Recommended Practice for General Gas Chro-
matography Procedures.
2.1.3 Method E355 - Practice for Gas Chromatography Terms and
Relationships.
2.2 EPA Documents
2'2'1 Quality Assurance Handbook for Air Pollution Measurement
Systems. Volume II - "Ambient Air Specific Methods,"
Section 2.2 - "Reference Method for the Determination of
Suspended Particulates in the Atmosphere," Revision 1,
July, 1979. EPA-600/4-77-027A.
2'2'2- Protocol for the Analysis of 2.3,7 .S-Tetrachlorodlbenzo-
P-Dioxin by High Resolution Gas Chromatography-High
Resolution Mass Spectrometry. U.S. Environmental Protection
Agency, January, 1986, EPA-600/4-86-004.
2'2*3 Evaluation of an EPA High Volume Air Sampler for Polychlori-
nated Dibenzo-p-dioxins and Polychlorinated Dibenzo-
furans, undated report by Battelle under Contract 68-02-
4127, Project Officers.Robert G. Lewis and Nancy K.
Wilson, U.S. Environmental Protection Agency. EMSL. Research
Triangle Park, North Carolina.
2'2'4 Compendium of Methods for the Determination of Toxic Organic
Compounds in Ambient Air. U.S. Environmental Protection
Agency, April, 1984, 600/4-84-041.
2'2'5 Technical Assistance Document for Sampling and Analysis of
Toxic Organic Compounds in Ambient Air. U.S. Environmental
Protection Agency, June, 1983, EPA-600/4-83-027.
-------
T09-3
2.3 Other Documents
2.3.1 General Metal Works Operating Procedures for Model PS-1
Sampler. General Metal Works, Inc., Village of Cleves,
Ohio.
2.3.2 Chicago Air Quality: PCB Air Monitoring Plan, Phase 2,
Illinois Environmental Protection Agency, Division of Air
Pollution Control, April, 1986, IEPA/APC/86-011.
3. Summary of Method
3.1 Filters and adsorbent cartridges (containing PUF) are cleaned in
solvents and vacuum-dried. The filters and adsorbent cartridges
are stored in screw-capped jars wrapped in aluminum foil (or
otherwise protected from light) before careful installation
on a modified high volume sampler.
3.2 Approximately 325 m3 of ambient air is drawn through a cartridge
on a calibrated General Metal Works Model PS-1 Sampler, or equi-
valent (breakthrough has not been shown to be a problem with
sampling volumes of 325 m3).
3.3 The amount of air sampled through the adsorbent cartridge is
recorded, and the cartridge is placed in an appropriately
labeled container and shipped along with blank adsorbent
cartridges to the analytical laboratory for analysis.
3.4 The filters and PUF adsorbent cartridge are extracted together
with benzene. The extract is concentrated, diluted with hexane,
and cleaned up using column chromatography.
3.5 The High-Resolution Gas Chromatography/High-Resolution Mass Spect-
rometry (HRGC/HRMS) system is verified to be operating properly
and is calibrated with five concentration calibration solutions,
each analyzed in triplicate.
3.6 A preliminary analysis of a sample of the extract is performed to
check the system performance and to ensure that the samples are
within the calibration range of the instrument. If necessary,
recalibrate the instrument, adjust the amount of the sample
injected, adjust the calibration solution concentration, and
adjust the data processing system to reflect observed retention
times, etc.
-------
T09-4
3.7 The samples and the blanks are analyzed by HRGC/HRMS and the
results are used (along with the amount of air sampled) to
calculate the concentrations of polychlorinated dioxins in
ambient air.
4. Significance
4.1 Polychlorinated dibenzo-p-dioxins (PCDDs) are extremely toxic.
They are carcinogenic and are of major environmental concern.
Certain isomers, for example, 2,3,7,8-tetrachlorodibenzo-p-
dioxin (2,3,7,8-TCDD), have LD50 values in the parts-per-tril-
lion range for some animal species. Major sources of these
compounds have been commercial processes involving polychlorinated
phenols and polychlorinated biphenyls (PCBs). Recently, however,
combustion sources have been shown to emit polychlorinated
dibenzo-p-dioxin (PCDD), including the open-flame combustion of
wood containing chlorophenol wood preservatives, and emissions
from burning transfonners and/or capacitors that contain PCBs
and chlorobenzenes.
4.2 Several documents have been published which describe sampling and
analytical approaches for PCDDs, as outlined in Section 2.2. The
attractive features of these methods have been combined in this
procedure. This method has not been validated in its final
form, and, therefore, one must use caution when employing it for
specific applications.
4.3 The relatively low level of PCDDs in the environment requires
the use of high volume sampling techniques to acquire sufficient
samples for analysis. However, the volatility of PCDDs prevents
efficient collection on filter media. Consequently, this method
utilizes both a filter and a PUF backup cartridge which provides
for efficient collection of most PCDDs.
-------
T09-5
5. Definitions
Definitions used in this document and in any user-prepared standard
operating procedures (SOPs) should be consistent with ASTM Methods
D1356 and E355 (Sections 2.1.1 and 2.1.3). All abbreviations and
symbols within this document are defined the first time they are
used.
6. Interferences
6.1 Chemicals that elute from the gas chromatographic (GC) column
within ^10 scans of the standards or compounds of interest and
which produce, within the retention time windows, ions with any
mass-to-charge (m/e) ratios close enough to those of the ion
fragments used to detect or quantify the analyte compounds are
potential interferences. Most frequently encountered potential
interferences are other sample components that are extracted
along with PCDDs, e.g., polychlorinated biphenyls (PCBs), metho-
xybiphenyls, chlorinated hydroxydiphenylethers, chlorinated naph-
thalenes, DDE, DDT, etc. The actual incidence of interference
by these compounds also depends upon relative concentrations,
mass spectrometric resolution, and chromatographic conditions.
Because very low levels of PCDDs must be measured, the elimina-
tion of interferences is essential. High-purity reagents and
solvents must be used and all equipment must be scrupulously
cleaned. Laboratory reagent blanks must be analyzed to demon-
strate absence of contamination that would interfere with the
measurements. Column chromatographic procedures are used to
remove some coextracted sample components; these procedures must
be performed carefully to minimize loss of analyte compounds
during attempts to increase their concentration relative to
other sample components.
6.2 In addition to chemical interferences, inaccurate measurements
could occur if PCDDs are retained on particulate matter, the
filter, or PUF adsorbent cartridge, or are chemically changed
during sampling and storage in ways that are not accurately
measured by adding isotopically labeled spikes to the samples.
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T09-6
6.3 The system cannot separately quantify gaseous PCDDs and parti-
culate PCDDs because the material may be lost from the filter
by volatilization after collection and may be transferred to
the absorbent cartridge. Gaseous PCDDs may also be adsorbed on
particulate matter on the filter.
Apparatus
7.1 General Metal Works (GMW) Model PS-1 Sampler.
7.2 At least two Model PS-1 sample cartridges and filters per PS-1
Sampler.
7.3 Calibrated GMW Model 40 calibrator.
7.4 High-Resolution Gas Chromatograph/High-Resolution Mass
Spectrometer/Data System (HRGC/HRMS/DS)
7.4.1 The GC must be equipped for temperature programming, and
all required accessories must be available, including
syringes, gases, and a capillary column. The GC injection
port must be designed for capillary columns. The use of
splitless injection techniques is recommended. On-
column injection techniques can be used but they may
severely reduce column lifetime for nonchemically bonded
columns. In this protocol, a 2-uL injection volume is
used consistently. With some GC injection ports, however,
1-uL injections may produce some improvement in precision
and chromatographic separation. A 1-uL injection volume
may be used if adequate sensitivity and precision can be
achieved.
[NOTE: If 1 uL is used as the injection volume, the injection
volumes for all extracts, blanks, calibration solutions
and performance check samples must be 1 uL.]
7.4.2 Gas Chromatograph-Mass Spectrometer Interface.
The gas chromatograph is usually coupled directly to the
mass spectrometer source. The interface may include a
diverter valve for shunting the column effluent and
isolating the mass spectrometer source. All components
of the interface should be glass or glass-lined stainless
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T09-7
steel. The interface components should be compatible with
300°C temperatures. Cold spots and/or active surfaces
(adsorption sites) in the GC/MS interface can cause peak
tailing and peak broadening. It is recommended that the
GC column be fitted directly into the MS source. Graphic
ferrules should be avoided in the GC injection area
since they may adsorb TCDD. Vespel® or equivalent
ferrules are recommended.
7.4.3 Mass Spectrometer. The static resolution of the instru-
ment must be maintained at a minimum of 10,000 (10 percent
valley). The mass spectrometer must be operated in a
selected ion monitoring (SIM) mode with a total cycle time
(including voltage reset time) of one second or less
(Section 12.3.4.1). At a minimum, ions that occur at
the following masses must be monitored:
2,3,7,8-TCDD 1.2.3,4,7,8-HyCDD OCDD
258.9300 326.8521 394.7742
319.8965 389.8156 457.7377
321.8936 391.8127 459.7347
331.9368
333.93338
7.4.4 Data System. A dedicated computer data system is employed
to control the rapid multiple ion monitoring process and
to acquire the data. Quantification data (peak areas or
peak heights) and SIM traces (displays of intensities of
each m/z being monitored as a function of time) must be
acquired during the analyses. Quantifications may be
reported based upon computer-generated peak areas or upon
measured peak heights (chart recording). The detector
zero setting must allow peak-to-peak measurement of the
noise on the baseline.
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T09-8
7.4.5 GC Column. A fused silica column (30 m x 0.25 mm I.D.)
coated with DB-5, 0.25 u film thickness (J & s Scientific,
Inc., Crystal Lake, IL) is utilized to separate each of
the several tetra- through octa-PCDDs, as a group, from all
of the other groups. This column also resolves 2,3,7,8-TCDD
from all 21 other TCDD isomers; therefore, 2,3,7,8-TCDD
can be determined quantitatively if proper calibration
procedures are followed as per Sections 12.3 through 12.6.
Other columns may be used for determination of PCDDs, but
separation of the wrong PCDD isomers must be demonstrated
and documented. Minimum acceptance criteria must be
determined as per Section 12.1. At the beginning of each
12-hour period (after mass resolution has been demonstrated)
during which sample extracts or concentration calibration
solutions will be analyzed, column operating conditions
must be attained for the required separation on the
column to be used for samples.
7.5 All required syringes, gases, and other pertinent supplies to
operate the HRGC/HRMS system.
7.6 Airtight, labeled screw-capped containers to hold the sample car-
tridges (perferably glass with Teflon seals or other noncontaminat-
ing seals).
7.7 Data sheets for each sample for recording the location and sample
time, duration of sample, starting time, and volume of air sampled.
7.8 Balance capable of weighing accurately to _+0.001 g.
7.9 Pipettes, micropipets, syringes, burets, etc., to make calibra-
tion and spiking solutions, dilute samples if necessary, etc..
including syringes for accurately measuring volumes such
as 25 uL and 100 uL of isotopically labeled dioxin solutions.
7.10 Soxhlet extractors capable of extracting GMW PS-1 PUF adsorbent
cartridges (2.3" x 5" length), 500-mL flask, and condenser.
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T09-9
7.11 Vacuum drying oven system capable of maintaining the PUF car-
tridges being evacuated at 240 torr (flushed with nitrogen)
overnight.
7.12 Ice chest - to store samples at 0°C after collection.
7.13 Glove box for working with extremely toxic standards and
reagents with explosion-proof hood for venting fumes from
solvents reagents, etc.
7.14 Adsorbtion columns for column chromatography - 1 cm x 10 cm
and 1 cm x 30 cm, with stands.
7.15 Concentrator tubes and a nitrogen evaporation apparatus with
variable flow rate.
7.16 Laboratory refrigerator with chambers operating at 0°C
and 4°C.
7.17 Kuderna-Danish apparatus - 500 ml evaporating flask, 10 ml
graduated concentrator tubes with ground-glass stoppers,
and 3-ball macro Snyder Column (Kontes K-570001-0500,
K-50300-0121, and K-569001-219, or equivalent).
7.18 Two-ball micro Snyder Column, Kuderna-Danish (Kontes
569001-0219, or equivalent).
7.19 Stainless steel spatulas and spoons.
7.20 Minivials - 1 ml, borosilicate glass, with conical reservoir
and screw caps lined with Teflon-faced silicone
disks, and a vial holder.
7.21 Chromatographic columns for Carbopak cleanup - disposable
5-mL graduated glass pipets, 6 to 7 mm ID.
7.22 Desiccator.
7.23 Polyester gloves for handling PUF cartridges and filter.
7.24 Die - to cut PUF plugs.
7.25 Water bath equipped with concentric ring cover and capable
of being temperature-controlled within ^2°C.
7.26 Erlenmeyer flask, 50 ml.
7.27 Glass vial, 40 ml.
7.28 Cover glass petri dishes for shipping filters.
7.29 Fritted glass extraction thimbles.
7.30 Pyrex glass tube furnace system for activating silica
gel at 180°C under purified nitrogen gas purge for an hour,
with capability of raising temperature gradually.
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T09-10
[NOTE: Reuse of glassware should be minimized to avoid the risk of
cross-contamination. All glassware that is used, especially glassware
that 1S reused, must be scrupulously cleaned as soon as possible after
use. Rinse glassware with the last solvent used in it and then with
high-purity acetone and hexane. Wash with hot water containing
detergent. Rinse with copious amount of tap water and several
portions of distilled water. Drain, dry, and heat in a muffle furnace
at 400°C for 2 to 4 hours.- Volumetric glassware must not be heated
in a muffle furnace; rather, it should be rinsed with high-purity
acetone and hexane. After the glassware is dry and cool, rinse it with
hexane, and store it inverted or capped with solvent-rinsed aluminum
foil in a clean environment.]
8. Reagents and Materials
8.1 Ultrapure glass wool, silanized, extracted with methylene
chloride and hexane, and dried.
8.2 Ultrapure acid-washed quartz fiber filters for PS-1
Sampler (Pallfex 2500 glass, or equivalent).
8.3 Benzene (Burdick and Jackson, glass-distilled, or equivalent).
8.4 Hexane (Burdick and Jackson, glass-distilled, or equivalent).
8.5 Alumina, acidic - extracted in a Soxhlet apparatus with
methylene chloride for 6 hours (minimum of 3 cycles
per hour) and activated by heating in a foil-covered
glass container for 24 hours at 190°C.
8.6 Silica gel - high-purity grade, type 60, 70-230 mesh;
extracted in a Soxhlet apparatus with methylene chloride
for 6 hours (minimum of 3 cycles per hour) and activated
by heating in a foil-covered glass container for 24 hours
at 130°C.
8.7 Silica gel impregnated with 40 percent (by weight) sulfuric
acid - prepared by adding two parts (by weight) concentrated
sulfuric acid to three parts (by weight) silica gel (extracted
and activated) and mixiing with a glass rod until free of lumps;
- stored in a screw-capped glass bottle.
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T09-11
8 8 Graphitized carbon black (Carbopak C or equivalent),
surface of approximately 12 m2/g, 80/100 mesh - prepared by
thoroughly mixing 3.6 grams Carbopak C and 16.4 grams Celite
545« in a 40-mL vial and activating at 130'C for six hours;
stored in a desiccator.
8.9 Sulfuric Acid, ultrapure, ACS grade, specific gravity 1.84.
8.10 Sodium Hydroxide, ultrapure, ACS grade.
8 11 Native and isotopically labeled PCDD/PCDF isomers for
calibration and spiking standards, from Cambridge Isotopes,
Cambridge, MA.
8.12 n-decane (Aldrich Gold Label grade [D90-1], or equivalent).
8.13 Toluene (high purity, glass-distilled).
8 14 Acetone (high purity, glass-distilled).
8.15 Filters, quartz fiber - Pall flex 2500 QAST, or equivalent.
8.16 Ultrapure nitrogen gas (Scott chromatographic grade, or equivalent).
8.17 Methanol (chromatographic grade).
8 18 Methylene chloride (chromatographic grade, glass-distilled).
8 19 Dichloromethane/hexane (3:97, v/v), chromatographic grade.
8.20 Hexane/dichloromethane (1:1, v/v), chromatogtraphic grade.
8.21 Perfluorokerosene (PFK), chromatographic grade.
8 22 Celite 545®, reagent grade, or equivalent.
8.23 Membrane filters or filter paper with pore sizes less than
25 urn, hexane-rinsed.
8 24 Granular anhydrous sodium sulfate, reagent grade.
8*.25 Potassium carbonate-anhydrous, granular, reagent grade.
8.26 Cyclohexane, glass-distilled.
8.27 Tridecane, glass-distilled.
8.28 2,2,3-trimethylpentane, glass-distilled.
8.29 Isooctane, glass-distilled.
8.30 Sodium sulfate, ultrapure, ACS grade.
8.31 Polyurethane foam - 3 inches thick sheet stock, polyether
type used in furniture upholstering, density 0.022 g/cm .
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T09-12
8.32 Concentration calibration solutions (Table 1) - four tridecane
solutions containing 13Cl2-l,2,3,4-TCDD (recovery standard)
and unlabeled 2,3,7,8-TCDD at varying concentrations, and
C12-2,3.7,8-TCDD (internal standard, CAS RN 80494-19-5).
These solutions must be obtained from the Quality Assurance
Division, U.S. EPA. Environmental Monitoring Systems Laboratory
(EMSL-LV), Las Vegas, Nevada, and must be used to calibrate
the instrument. However, secondary standards may be obtained
from commercial sources, and solutions may be prepared in the
analytical laboratory. Traceability of standards must be
verified against EPA-supplied standard solutions by procedures
documented in laboratory SOPs. Care must be taken to use the
correct standard. Serious overloading of instruments may occur
if concentration calibration solutions intended for low-resolution
MS are injected into the high-resolution MS.
8.33 Column performance check mixture dissolved in 1 mL of tridecane
from Quality Assurance Division (EMSL-LV). Each ampule of this
solution will contain approximately 10 ng of the following
components (A) eluting near 2,3,7,8-TCDD and of the first (F)
and last-eluting (L) TCDDs, when using the recommended columns
at a concentration of 10 pg/uL of each of these isomers:
o unlabeled 2,3,7,8-TCDD
o 13C12-2,3,7,8-TCDD
o 1,2,3,4-TCDD (A)
o 1,4,7,8-TCDD (A)
o 1,2,3,7-TCDD (A)
o 1,2,3,8-TCDD (A)
o 1,3,6,8-TCDD (F)
0 1,2,8,9-TCDD (L)
If these solutions are unavailable from EPA. they should be
prepared by the analytical laboratory or a chemical supplier
and analyzed in a manner traceable to the EPA performance
check mixture designed for 2,3,7,8-TCDD monitoring. Similar
mixtures of isotopically labeled compounds should be prepared
to check performance for monitoring other specific forms of
TCDD that are of interest.
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T09-13
8.34 Sample fortification solution - isooctane solution contain-
ing the internal standard at a nominal concentration of 10 pg/uL.
8.35 Recovery standard spiking solution - tridecane solution con-
taining the isotopically labeled standard (13C12-2,3f7,8-TCDD
and other PCDDs of interest) at a concentration of 10.0 pg/uL.
8.36 Field blank fortification solutions - isooctane solutions
containing the following:
0 Solution A: 10.0 pg/uL of unlabeled 2,3,7,8-TCDD
0 Solution B: 10.0 pg/uL of unlabeled 1,2,3,4-TCDD
[NOTE: These reagents and the detailed analytical procedures described
herein are designed for monitoring TCDD isomer concentrations of
6.0 pg/m3 to 37 pg/m3 each. If ambient concentrations should exceed
these levels, concentrations of calibrations and spiking solutions
will need to be modified, along with the detailed sample preparation
procedures. The reagents and procedures described herein are based
on Appendix B of the Protocol for the Analysis of 2,3,7,8-TCDD
(Section 2.2.2) combined with the evaluation of the high volume air
sampler for PCDD.
Preparation of PUF Sampling Cartridge
9.1 The PUF adsorbent is a polyether-type polyurethane foam (density
No. 3014 or 0.0225 g/cm3) used for furniture upholstery.
9.2 The PUF inserts are 6.0-cm diameter cylindrical plugs cut from
3-inch sheet stock and should fit, with slight compression, in the
glass cartridge, supported by the wire screen (Figure 1). During
cutting, the die is rotated at high speed (e.g., in a drill
press) and continuously lubricated with water.
9.3 For initial cleanup, the PUF plug is placed in a Soxhlet appara-
tus and extracted with acetone for 14-24 hours at approximately
4 cycles per hour. When cartridges are reused, 5% diethyl
ether in n-hexane can be used as the cleanup solvent.
9,4 The extracted PUF is placed in a vacuum oven connected to a
water aspirator and dried at room temperature for approximately
2-4 hours (until no solvent odor is detected).
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num
T09-14
9.5 The PUF is placed into the glass sampling cartridge using poly-
ester gloves. The module is wrapped with hexane-rinsed alumi
foil, placed in a labeled container, and tightly sealed.
9.6 At least one assembled cartridge from each batch must be
analyzed, as a laboratory blank, using the procedures described
in Section 11, before the batch is considered acceptable for
field use. A blank level of <10 ng/plug for single compounds
is considered to be acceptable.
10. Sample Collection
10.1 Description of Sampling Apparatus
10.1.1 The entire sampling system is diagrammed in Figure 2.
A unit specifically designed for this method is
commercially available (Model PS-1 - General Metal
Works, Inc., Village of Cleves, Ohio).
10.1.2 The sampling module (Figure 1) consists of a glass sampl-
ing cartridge and an air-tight metal cartridge holder.
The PUF is retained in the glass sampling cartridge.
10.2 Calibration of Sampling System
10.2.1 The airflow through the sampling system is monitored
by a Venturi/Magnehelic assembly, as shown in Figure 2.
Assembly must be audited every six months using an
audit calibration orifice, as described in the U.S.
EPA High Volume Sampling Method, 40 CFR 50, Appendix B.
A single-point calibration must be performed before
and after each sample collection, using the procedure
described in Section. 10.2.2.
10.2.2 Prior to calibration, a "dummy" PUF cartridge and filter
are placed in the sampling head and the sampling motor
is activated. The flow control valve is fully opened
and the voltage variator is adjusted so that a sample
flow rate corresponding to 110% of the desired flow rate
is indicated on the Magnehelic (based on the previously
obtained multipoint calibration curve). The motor is
allowed to warm up for 10 minutes and then the flow control
-------
T09-15
valve is adjusted to achieve the desired flow rate. The
ambient temperature and barometric pressure should be
recorded on an appropriate data sheet.
10.2.3 The calibration orifice is placed on the sampling
head and a manometer is attached to the tap on the
calibration orifice. The sampler is momentarily
turned off to set the zero level of the manometer.
The sampler is then switched on and the manometer
reading is recorded after a stable reading is
achieved. The sampler is then shut off.
10.2.4 The calibration curve for the orifice is used to cal-
culate sample flow from the data obtained in Section
10.2.3, and the calibration curve for the Venturi/
Magnehelic assembly is used to calculate sample flow
from the data obtained in Section 10.2.2. The calibra-
tion data should be recorded on an appropriate data
sheet. If the two values do not agree within 10%, the
sampler should be inspected for damage, flow blockage,
etc. If no obvious problems are found, the sampler
should be recalibrated (multipoint) according to the
U.S. EPA High Volume Sampling Method (Section 10.2.1).
10.2.5 A multipoint calibration of the calibration orifice,
against a primary standard, should be obtained annually.
10.3 Sample Collection
10.3.1 After the sampling system has been assembled and
calibrated as described in Sections 10.1 and 10.2, it
can be used to collect air samples, as described in
Section 10.3.2.
10.3.2. The samples should be located in an unobstructed area,
at least two meters from any obstacle to air flow.
The exhaust hose should be stretched out in the down-
wind direction to prevent recycling of air.
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T09-16
10.3.3 A clean PUF sampling cartridge and quartz filter are
removed from sealed transport containers and placed in
the sampling head using forceps and gloved hands. The
head is tightly sealed into the sampling system. The
aluminum foil wrapping is placed back in the sealed
container for later use.
10.3.4 The zero reading of the Magnehelic is checked. Ambient
temperature, barometric pressure, elapsed time meter
setting, sampler serial number, filter number, and
PUF cartridge number are recorded on a suitable data
sheet, as illustrated in Figure 3.
10.3.5 The voltage variator and flow control valve are placed
at the settings used in Section 10.2.3, and the power
switch is turned on. The elapsed time meter is acti-
vated and the start time is recorded. The flow (Magne-
helic setting) is adjusted, if necessary, using the
flow control valve.
10.3.6 The Magnehelic reading is recorded every six hours
during the sampling period. The calibration curve
(Section 10.2.4) is used to calculate the flow rate.
Ambient temperature and barometric pressure are
recorded at the beginning and end of the sampling
period.
10.3.7 At the end of the desired sampling period, the power is
turned off and the filter and PUF cartridges are wrapped
with the original aluminum fail and placed in sealed,
labeled containers for transport back to the laboratory.
10.3.8 The Magnehelic calibration is checked using the cali-
bration orifice, as described in Section 10.2.4. If
calibration deviates by more than 10% from the initial
reading, the flow data for that sample must be marked
as suspect and the sampler should be inspected and/or
removed from service.
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T09-17
10.3.9 At least one field filter/PUF blank will be returned to
the laboratory with each group of samples. A field
blank is treated exactly as a sample except that no air
is drawn through the filter/PUF cartridge assembly.
10.3.10 Samples are stored at 20°C in an ice chest until receipt
at the analytical laboratory, after which they are
refrigerated at 4°C.
11. Sample Extraction
11.1 Immediately before use, charge the Soxhlet apparatus with 200
to 250 ml of benzene and reflux for 2 hours. Let the apparatus
cool, disassemble it, transfer the benzene to a clean glass
container, and retain it as a blank for later analysis, if
required. After sampling, spike the cartridges and filters
with an internal standard (Table 1). After spiking, place the
PUF cartridge and filter together in the Soxhlet apparatus
(the use of an extraction thimble is optional). (The filter and
PUF cartridge are analyzed together in order to reach detection
limits, avoid questionable interpretation of the data, and mini-
mize cost.) Add 200 to 250 ml of benzene to the apparatus and
relux for 18 hours at a rate of at least 3 cycles per hour.
11.2 Transfer the extract to a Kuderna-Danish (K-D) apparatus, concen-
trate it to 2 to 3 ml, and let it cool. Rinse the column and
flask with 5 ml of benzene, collecting the rinsate in the concen-
trator tube to 2 to 3 ml. Repeat the rinsing and concentration
steps twice more. Remove the concentrator tube from the K-D
apparatus and carefully reduce the extract volume to approximately
1 ml with a stream of nitrogen using a flow rate and distance
above the solution such that a gentle rippling of the solution
surface is observed.
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T09-18
11.3 Perform the following column chromatographic procedures for
sample extraction cleanup. These procedures have been
demonstrated to be effective for a mixture consisting of:
0 1,2,3,4-TCDD
1,2,3,4,7,8-HXCDD
0 OCDD
0 2,3,7,8-TCDD
11.3.1 Prepare an acidic silica gel column as follows (Figure 4)
Pack a 1 cm x 10 cm chromatographic column with a glass
wool plug, a 1-cm layer of Na2S04/K2C03 (1:1), 1.0 g of
silica gel (Section 8.6), and 4.0 g of 40-percent (w/w)
sulfuric acid-impregnated silica gel (Section 8.7).
Pack a second chromatographic column (1 cm x 30 cm)
with a glass wool plug and 6.0 g of acidic alumina
(Section 8.5), and top it with a 1-cm layer of sodium
sulfate (Section 8.30). Add hexane to the columns
until they are free of channels and air bubbles.
11.3.2 Quantitatively transfer the benzene extract (1 ml)
from the concentrator tub to the top of the silica
gel column. Rinse the concentrator tube with 0.5-mL
portions of hexane. Transfer the rinses to the top of
the silica gel column.
11.3.3 Elute the extract from the silica gel column with 90 of
ml hexane directly into a Kudena-Danish concentrator
tube. Concentrate the eluate to 0.5 ml. using nitro-
gen blowdown, as necessary.
11.3.4 Transfer the concentrate (0.5 ml) to the top of the
alumina column. Rinse the K-D assembly with two
0.5-mL portions of hexane, and transfer the rinses to
the top of the alumina column. Elute the alumina
column with 18 mL hexane until the hexane level is
just below the top of the sodium sulfate. Discard the
eluate. Do not let the columns reach dryness
(i.e., maintain a solvent "head").
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T09-19
11.3.5 Place 30 mL of 20% (v/v) methylene chloride in hexane
on top of the alumina column and elute the TCDDs from
the column. Collect this fraction in a 50-mL Erlenmeyer
flask.
11.3.6 Certain extracts, even after cleanup by column chroma-
tography, contain interferences that preclude
determination of TCDD at low parts-per-trillion
levels. Therefore, a cleanup step is included using
activated carbon which selectively retains planar
molecules such as TCDDs. The TCDDs are then removed
from the carbon by elution with toluene. Proceed as
follows: Prepare an 18% Carbopak C/Celite 545* mixture
by thoroughly mixing 3.6 grams Carbopak C (80/100 mesh)
and 16.4 grams Celite 545® in a 40-mL vial. Activate
the mixture at 130°C for 6 hours, and store it in a
desiccator. Cut off a clean 5-mL disposable glass
pipet at the 4-mL mark. Insert a plug of glass wool
(Section 8.1) and push it to the 2-mL mark. Add 340 mg
of the activated Carbopak/Celite mixture followed by
another glass wool plug. Using two glass rods, push both
glass wool plugs simultaneously toward the Carbopak/Celite
plug to a length of 2.0 to 2.5 cm. Pre-elute the column
with 2 ml of toluene followed by 1 ml of 75:20:5 methylene
chloride/methanol/ benzene, 1 ml of 1:1 cyclohexane in
methylene choride, and 2 ml of hexane. The flow rate
should be less than 0.5 ml per minute. While the column
is still wet with hexane, add the entire elute (30 ml)
from the alumina column (Section 11.3.5) to the top of
the column. Rinse the Erlenmeyer flask that contained the
extract twice with 1 ml of hexane and add the rinsates
to the top of the column. Elute the column sequentially
with two 1-mL aliquots of hexane, 1 ml of 1:1 cyclohex-
ane in methylene chloride, and 1 mL of 75:20:5 methylene
-------
T09-20
chloride/mentanol/benzene. Turn the column upside
down and elute the TCDD fraction into a concentrator
tube with 6 ml of toluene. Warm the tube to approxi-
mately 60°C and reduce the toluene volume to approxi-
mately 1 mL using a stream of nitrogen. Carefully
transfer the residue into a 1-mL minivial and, again
at elevated temperature, reduce the volume to about
100 uL using a stream of nitrogen. Rinse the concen-
trator tube with 3 washings using 200 uL of 1% toluene
in CH2C12 each time. Add 50 uL of tridecane and store
the sample in a refrigerator until GC/MS analysis is
performed.
12. HRGC/HRMS System Performance Criteria
The laboratory must document that the system performance criteria
specified in Sections 12.1, 12.2, and 12.3 have been met before
analysis of samples.
12.1 GC Column Performance
12.1.1 Inject 2 uL of the column performance check solution
(Section 8.33) and acquire selected ion monitoring
(SIM) data for m/z 258.930, 319.897, 321.894, and
333.933 within a total cycle time of
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T09-21
the retention time window for total TCDD determination.
The peaks representing 2,3,7,8-TCDD, and the first and
last eluting TCDD isomers must be labeled and identified.]
12.2 Mass Spectometer Performance
12.2.1 The mass spectrometer must be operated in the electron
(impact) ionization mode. Static mass resolution of at
least 10,000 (10% valley) must be demonstrated before any
analysis of a set of samples is performed (Section 12.2.2).
Static resolution checks must be performed at the beginn-
ing and at the end of each 12-hour period of operation.
However, it is recommended that a visual check (e.g., not
documented) of the static resolution be made using the
peak matching unit before and after each analysis.
12.2.2 Chromatography time for TCDD may exceed the long-term
mass stability of the mass spectrometer; therefore, mass
drift correction is mandatory. A reference compound
(high boiling perfluorokerosene [PFK] is recommended)
is introduced into the mass spectrometer. An acceptable
lock mass ion at any mass between m/z 250 and m/z 334
(m/z 318.979 from PFK is recommended) must be used to
monitor and correct mass drifts.
[NOTE: Excessive PFK may cause background noise problems and
contamination of the source, resulting in an increase in
"downtime" for source cleaning. Using a PFK molecular
leak, tune the instrument to meet the minimum required
mass resolution of 10,000 (10% valley) at m/z 254.986
(or any other mass reasonably close to m/z 259). Cali-
brate the voltage sweep at least across the mass range
m/z 259 to m/z 344 and verify that m/z 330.979 from PFK
(or any other mass close to m/z 334) is measured within
^5 ppm (i.e., 1.7 mmu). Document the mass resolution
by recording the peak profile of the PFK reference peak
m/z 318.979 (or any other reference peak at a mass close
to m/z 320/322). The format of the peak profile represen-
tation must allow manual determination of the resolution;
-------
T09-22
i.e., the horizontal axis must be a calibrated mass
scale (mmu or ppm per division). The result of the
peak width measurement (performed at 5 percent of the
maximum) must appear on the hard copy and cannot exceed
31.9 mmu or 100 ppm.]
12.3 Initial Calibration
Intitial calibration is required before any samples are analyzed
for 2,3,7,8-TCDD. Initial calibration is also required if any
routine calibration does not meet the required criteria listed
in Section 12.6.
12.3.1 All concentration calibration solutions listed in Table 1
must be utilized for the initial calibration.
12.3.2 Tune the instrument with PFK as described in
Section 12.2.2.
12.3.3 Inject 2 uL of the column performance check solution
(Section 8.33) and acquire SIM mass spectral data for m/z
258.930, 319.897, 321.894, 331.937, and 333.934 within
a total cycle time of
-------
T09-23
12.3.4.2 Acquire SIM data for the following selected
characteristic ions:
m/z Compound
258.930 TCDD - COC1
319.897 unlabeled TCDD
321.894 unlabeled TCDD
331.937 13C12-2,3,7,8-TCDD,
13C12-1,2,3,4-TCDD
333.934 13C12-2,3,7,8-TCDD,
13C12-1,2,3,4-TCDD
12.3.4.3 The ratio of intergrated ion current for m/z
319.897 to m/z 321.894 for 2,3,7,8-TCDD must
be between 0.67 and 0.87 (+13%).
12.3.4.4 The ratio of integrated ion current for m/z
331.937 to m/z 333.934 for 13C12-2,3,7,8-TCDD
and 13C12-1,2.3,4-TCDD must be between 0.67
and 0.87.
12.3.4.5 Calculate the relative response factor for
unlabeled 2,3,7,8-TCDD [RRF(I)] relative to
13C12-2S3,758-TCDD and for labeled 13C12-
2,3,7,8-TCDD [RRF(II)] relative to 13C12-
1,2,3,4-TCDD as follows:
A» n
Y ^T ^
RRF(I) = ___
QX * AIS
RRF(II)-
ARS
-------
T09-24
where:
Ax = sum of the integrated abundances of m/z 319.897
and m/z 321.894 for unlabeled 2,3,7,8,-TCDD.
= sum of the integrated abundances of m/z 331.937
and m/z 333.934 for 13C12-2,3,7,8-TCDD.
sum of the integrated abundances for m/z 331.937
and m/z 333.934 for 13C12-1,2,3,4-TCDD.
QJS = quantity (pg) of 13C12-2,3,7,8-TCDD injected.
QRS = quantity (pg) of 13C12-1,2,3,4-TCDD injected.
Qx = quantity (pg) of unlabeled 2,3,7,8-TCDD injected.
12.4 Criteria for Acceptable Calibration
The criteria listed below for acceptable calibration must be met
before analysis of any sample is performed.
12.4.1 The percent relative standard deviation (RSD) for the
response factors from each of the triplicate analyses
for both unlabeled and 13C12-2,3S7,8-TCDD must be less
than ±20%.
12.4.2 The variation of the five mean RRFs for unlabeled
2,3,7,8-TCDD obtained from the triplicate analyses
must be less than _+20% RSD.
12.4.4 SIM traces for 13C12-2,3,7,8-TCDD must present a
signal-to-noise ratio _>10 for 333.934.
12.4.5 Isotopic ratios (Sections 12.3.4.3 and 12.3.4.4) must
be within the allowed range.
[NOTE: If the criteria for acceptable calibration listed in
Sections 12.4.1 and 12.4.2 have been met, the RRF can
be considered independent of the analyte quantity for
the calibration concentration range. The mean RRF
from five triplicate determinations for unlabeled
2.3,7,8-TCDD and for 13Cl22,3,7,8-TCDD will be used for
all calculations until routine calibration criteria
(Section 12.6) are no longer met. At such time, new
mean RRFs will be calculated from a new set of five
triplicate determinations.]
-------
T09-25
12.5 Routine Calibration
Routine calibration must be performed at the beginning of each
12-hour period after successful mass resolution and GC column
performance check runs.
12.5.1 Inject 2 uL of the concentration calibration solution
(Section 8.32) that contains 5.0 pg/uL of unlabeled
2,3,7,8-TCDD, 10.0 pg/uL of 13C12-2,3,7,8-TCDD, and 5.0
pg/uL 13C12-1,2,3,4-TCDD. Using the same GC/MS/DS
conditions as in Sections 12.1, 12.2, and 12.3, deter-
mine and document acceptable calibration as provided
in Section 12.6.
12.6 Criteria for Acceptable Routine Calibration
The following criteria must be met before further analysis is
performed. If these criteria are not met, corrective action
must be taken and the instrument must be recalibrated.
12.6.1 The measured RRF for unlabeled 2,3,7,8-TCDD must be
within +20 percent of the mean values established
(Section 12.3.4.5) by triplicate analyses of concen-
tration calibration solutions.
12.6.2 The measured RRF for 13Cl2-2,3,7,8-TCDD must be within
+20 percent of the mean value established by triplicate
analyses of concentration calibration solutions
(Section 12.3.4.5).
12.6.3 Isotopic ratios (Sections 12.3.4.3 and 12.3.4.4) must be
within the allowed range.
12.6.4 If one of the above criteria is not satisfied, a second
attempt can be made before repeating the entire initial-
ization process (Section 12.3).
[NOTE: An initial calibration must be carried out whenever any
HRCC solution is replaced.]
13. Analytical Procedures
13.1 Remove the sample extract or blank from storage, allow it to
warm to ambient laboratory temperature, and add 5 uL of recovery
standard solution. With a stream of dry, purified nitrogen,
reduce the extract/blank volume to 20 uL.
-------
T09-26
13.2 Inject a 2-uL aliquot of the extract into the GC? which should
be operating under the conditions previously used (Section 12.1)
to produce acceptable results with the performance check
solution.
13.3 Acquire SIM data using the same acquisition time and MS operating
conditions previously used (Section 12.3.4) to determine the
relative response factors for the following selected characteristic
ions:
m/z Compound
258.930 TCDD - COC1 (weak at detection limit level)
319.897 unlabeled TCDD
321.894 unlabeled TCDD
331.937 13C12-2,3,7,8-TCDD, 13C]2-1,2,3,4-TCDD,
333.934 13C12-2,3,7,8-TCDD, 13C12-1,2,3,4-TCDD,
13.4 Identification Criteria
13.4.1 The retention time (RT) (at maximum peak height) of
the sample component m/z 319.897 must be within -1 to
+3 seconds of the retention time of the peak for the
isotopically labeled internal standard at m/z 331.937
to attain a positive identification of 2,3.7,8-TCDD.
Retention times of other tentatively identified TCDDs
must fall within the RT window established by analyzing
the column performance check solution (Section 12.1).
Retention times are required for all chromatograms.
13.4.2 The ion current responses for m/z 258.930, 319.897
and 321.894 must reach their maxima simultaneously
(+1 scan), and all ion current intensities must be
>2.5 times noise level for positive identification of
a TCDD.
13.4.3 The integrated ion current at m/z 319.897 must be
between 67 and 87 percent of the ion current response
at m/z 321.894.
-------
T09-27
t
13.4.4 The integrated ion current at m/z 331.937 must be
between 67 and 87 percent of the ion current response
at m/z 333.934.
13.4.5 The integrated ion currents for m/z 331.937 and 333.934
must reach their maxima within +1 scan.
13.4.6 The recovery of the internal standard 13C12-2,3,7,8-
TCDD must be between 40 and 120 percent.
14. Calculations
14.1 Calculate the concentration of 2,3,7,8-TCDD (or any other TCDD
isomer) using the formula:
Cx *
AIS • V • RRF(I)
where:
Cx - quantity (pg) of unlabeled 2,3,7,8-TCDD (or any other
unlabeled TCDD isomer) present.
AX = sum of the integrated ion abundances determined for m/z
319.897 and 321.894.
AIS = sum °f the integrated ion abundances determined for m/z
331.937 and 333.934 of 13Cl2-2,3,7,8-TCDD (IS = internal
standard).
QIS = quantity (pg) of 13C12-2,3,7,8-TCDD added to the
sample before extraction (Qjs = 500 pg).
V = volume (m3) of air sampled.
RRF(I) = Calculated mean relative response factor for unlabeled
2,3,7,8-TCDD relative to 13C12-2,3,7,8-TCDD. This value
represents the grand mean of the RRF(I)s obtained in
Section 12.3.4.5.
-------
T09-28
14.2 Calculate the recovery of the internal standard 13C-,2-2. 3,7,8
TCDD, measured in the sample extract, using the formula:
AIS ' QRS
Internal standard, x 100
percent recovery =
ARS • RRF(II) •
where:
and QlS = same definitions as above (Section 14.1)
ARS = sum of the integrated ion abundances determined for m/z
331.937 and 333.934 of 13C12-1,2,3,4-TCDD (RS = recovery
standard).
QRS = quantity (pg) of 13C12-1,2,3,4-TCDD added to the
sample residue before HRGC-HRMS analysis (QRS = 500 pg).
RRF(II) = Calculated mean relative response factor for labeled ^Cip-
2,3,7,8-TCDD. This value represents the grand mean of the
RRF(II)s calculated in Section 12.3.4.5.
14.3 Total TCDD Concentration
14.3.1 All positively identified isomers of TCDD must be
within the RT window and meet all identification
criteria listed in Sections 13.4.2, 13.4.3, and 13.4.4.
Use the expression in Section 14.1 to calculate the
concentrations of the other TCDD isomers, with Cx be-
coming the concentration of any unlabeled TCDD isomer.
14.4 Estimated Detection Limit
14.4.1 For samples in which no unlabeled 2,3,7,8-TCDD was
detected, calculate the estimated minimum detectable
concentration. The background area is determined by
integrating the ion abundances for m/z 319.897 and
321.894 in the appropriate region and relating that
height area to an estimated concentration that would
produce that product area. Use the formula:
(2.5) • (A ) • (QIS)
CE = x 15
(AIS) - RRF(I) • (W)
-------
T09-29
where:
CE = estimated concentration of unlabeled 2,3,7,8-TCDD required
to produce Ax.
Ax = sum of integrated ion abundance for m/z 319.897 and 321.894
in the same group of >25 scans used to measure AI$.
AIS - sum of integrated ion abundance for the appropriate ion
characteristic of the internal standard, m/z 331.937 and
m/z 333.934.
QIS, RRF(I). and V retain the definitions previously stated in
Section 14.1. Alternatively, if peak height measurements are used
for quantification, measure the estimated detection limit by the peak
height of the noise in the TCDD RT window.
14.5 The relative percent difference (RPD) is calculated as follows:
RPD
Si - S2
(Mean Concentration)
Si - S2
Si + S2)/Z
Si and S2 represent sample and duplicate sample results.
14.6 The total sample volume (Vm) is calculated from the periodic
flow readings (Magnehelic) taken in Section 10.3.6 using the
following equation:
Q *<>2 •" QN T
*
where:
V = total sample volume (nr).
Q Qp *'*• QN = flow rates determined at the beginning, end, and inter-
mediate points during sampling (L/minute).
N = number of data points averaged.
T = elapsed sampling time (minutes).
-------
T09-30
14.7 The concentration of compound in the sample is calculated using
the following equation:
x 298
_
760
273 +
where:
V$ = total sample volume (m3) at 25°C and 760 mm Hg pressure.
Vm = total sample flow (m3) under ambient conditions.
PA » ambient pressure (mm Hg).
tA = ambient temperature (°C).
14.8 The concentration of compound in the sample is calculated
using the following equation:
A x V
where:
x V
CA = concentration (ug/m3) of analyte in the sample.
A = calculated amount of material determined by HRGC/HRMS.
Vi = volume (uL) of extract injected.
VE = final volume (mL) of extract.
V$ = total volume (m3) of air samples corrected to standard
conditions.
15. Performance Criteria and Quality Assurance
This section summarizes required quality assurance (QA) measures and
provides guidance concerning performance criteria that should be
achieved within each laboratory.
15.1 Standard Operating Procedures (SOPs)
15.1.1 Users should generate SOPs describing the following
activities in their laboratory: 1) assembly, calibra-
tion and operation of the sampling system with make
and model of equipment used; 2) preparation, purifica-
tion, storage, and handling of sampling cartridges and
filters; 3) assembly, calibration and operation of the
HRGC/HRMS system with make and model of equipment used;
4) all aspects of data recording and processing, in-
cluding lists of computer hardware and software used.
-------
T09-31
15.1.2 SOPs should provide specific stepwise instructions and
should be readily available to and understood by the
laboratory personnel conducting the work.
15.2 Process, Field, and Solvent Blanks
15.2.1 One PUF cartridge and filter from each batch of
approximately 20 should be analyzed, without shipment
to the field, for the compounds of interest to serve as
process blank.
15.2.2 During each sampling episode, at least one PUF cartridge
and filter should be shipped to the field and returned,
without drawing air through the sampler, to serve as a
field blank.
15.2.3 During the analysis of each batch of samples, at least
one solvent process blank (all steps conducted but no
PUF cartridge or filter included) should be carried
through the procedure and analyzed.
-------
T09-32
TABLE 1
COMPOSITION OF CONCENTRATION CALIBRATION SOLUTIONS
Recovery
13C -1
L12-l,
HRCC1
HRCC2
HRCC3
HRCC4
HRCC5
Standards
2,3,4-TCDD
2.5 pg/uL
5.0 pg/uL
10.0 pg/uL
20.0 pg/uL
40.0 pg/uL
Analyte
2,3,7,8-TCDD
2.5 pg/uL
5.0 pg/uL
10.0 pg/uL
20.0 pg/uL
40.0 pg/uL
Sample Fortification Solution
-Internal Standard
13C12-2,3,7,8-TCDD
10.0 pg/uL
10.0 pg/uL
10.0 pg/uL
10.0 pg/uL
10.0 pg/uL
5.0 pg/uL of 13C12-2,3,7,8-TCDD
Recovery Standard Spiking Solution
100 pg/uL 13C12-1,2,3,4-TCDD
Field Blank Fortification Solutions
A) 4.0 pg/uL of unlabeled 2,3,7,8-TCDD
B) 5.0 pg/uL of unlabeled 1,2,3,4-TCDD
-------
T09-33
TABLE 2
RECOMMENDED GC OPERATING CONDITIONS
Column coating SP-2330 (SP 2331) CP-SIL 88
Film thickness 0.20 urn 0.22 urn
Column dimensions 60 m x 0.24 mm 50 m x 0.22 mm
Helium linear velocity 28-29 cm/sec at 240°C 28-29 cm/sec at 240°C
Initial temperature 200°C 190°C
Initial time 4 min 3 min
Temperature program 200°C to 250°C at 190°C to 240°C at
4°C/min 5°C/min
-------
LOWER CANISTER
RETAINING SCREEN
GLASS CARTRIDGE AND
ADSORBENT
FILTER HOLDER SUPPORT
FILTER HOLDER WITH
SUPPORT SCREEN
4" DIAMETER FILTER
SILICONE RUBBER
GASKET
FILTER RETAINING RING
o
l£>
I
u>
-p.
SILICONE
RUBBER
GASKETS
FIGURE 1. SAMPLING HEAD
-------
T09-35
Magnehelic
Gauge
0-100 in.
Exhaust
Duct
(6 in. x 10 ft)
Sampling
Head
(See Figure 2)
^Pipe Fitting (1/2 in.)
Venturi
Voltage Variator
Elapsed Time Meter
7-Day
Timer
FIGURE 2. HIGH VOLUME AIR SAMPLER
GENERAL METAL WORKS (MODEL PS-1)
-------
Performed by
Date/Time
Calibration Orifice
Manometer S/N
S/N
Ambient Temperature
Bar. Press.
°C
_mm Hg
Sampler
S/N
Variac
Setting V
Timer OK?
Yes/No
Calibration Orifice
Data
Manometer,
in. H00
Flow Rate
scm/min'a/
Sampler
Venturi Data
Magnehelic,
in. H00
Flow Rate
s cm/mi n'")
% Difference Between
Calibration and Sample
Venturi Flow Rates
Comments
I
o»
Ot
(a) From Calibration Tables for Calibration Orifice or Venturi Tube
(b) From Calibration Tables for Venturi Tube in each Hi-Vol unit.
Date check by
Date
FIGURE 3. EXAMPLE SAMPLING DATA SHEET
-------
T09-37
SODIUM SULFATE
ACIDIC ALUMINA (-6.0 g)
GLASS WOOL PLUG
(a) ALUMINA COLUMN
SULFURIC ACID ON SILICA GEL (- 4.0 g)
SILICA GEL <- 1.0 g)
SODIUM SULFATE/POTASSIUM CARBONATE 11:1»
GLASS WOOL PLUG
(b) SILICA GEL COLUMN
FIGURE 4. MULTILAYERED EXTRACT CLEANUP COLUMNS
-------
-------
Revi sion 1.0
June, 1987
METHOD T010
METHOD FOR THE DETERMINATION OF ORGANOCHLORINE PESTICIDES IN
AMBIENT AIR USING LOW VOLUME POLYURETHANE FOAM (PUF) SAMPLING WITH GAS
CHROMATOGRAPHY/ELECTRON CAPTURE DETECTOR (GC/ECD)
1. Scope
1.1 This document describes a method for sampling and analysis of a
variety of organochlorine pesticides in ambient air. The procedure
is based on the adsorption of chemicals from ambient air on
polyurethane foam (PUF) using a low volume sampler.
1.2 The low volume PUF sampling procedure is applicable to multi.com-
ponent atmospheres containing organochlorine pesticide concentrations
from 0.01 to 50 ug/m3 over 4- to 24-hour sampling periods.
The detection limit will depend on the nature of the analyte and
the length of the sampling period.
1.3 Specific compounds for which the method has been employed are
listed in Table 1. The analysis methodology described in this
document is currently employed by laboratories using EPA Method
608. The sampling methodology has been formulated to meet the
needs of pesticide sampling in ambient air.
2. Applicable Documents
2.1 ASTM Standards
D1356 - Definitions of Terms Related to Atmospheric
Sampling and Analysis.
D1605-60 - Standard Recommended Practices for Sampling
Atmospheres for Analysis of Gases and Vapors.
E260 - Recommended Practice for General Gas Chroma-
tography Procedures.
E355 - Practice for Gas Chromatography Terms and
Relationships.
2.2 EPA Documents
-------
T010-2
2.2.1 Compendium of Methods for the Determination of Toxic
Organic Compounds in Ambient Air. EPA-600/4-84-041,
U.S. Environmental Protection Agency, Research Triangle
Park, NC, April 1984.
- 2-2.2 Manual of Analytical Methods for Determination of Pesti-
cides in Humans and Environmental Standards. EPA-
600/8-80-038, U.S. Environmental Protection Agency,
Research Triangle Park, NC, July 1982.
2.2.3 "Test Method 608, Organochlorine Pesticides and PCBs,"
in EPA-600/4-82-057, U. S. Environmental Protection
Agency, Cincinnati, Ohio, July 1982.
2.2.4 R. G. Lewis, ASTM draft report on standard practice
for sampling and analysis pesticides and polychlorinated
biphenyls in indoor atmospheres, U. S. Environmental
Protection Agency, Research Triangle Park, NC, June 1987,
3. Summary of Method
3.1 A low volume (1 to 5 L/minute) sampler is used to collect va-
pors on a sorbent cartridge containing PUF. Airborne particles
may also be collected, but the sampling efficiency is not known.
3.2 Pesticides are extracted from the sorbent cartridge with 5%
diethyl ether in hexane and determined by gas-liquid chro-
matography coupled with an electron capture detector (ECD).
For some organochlorine pesticides, high performance liquid
chromatography (HPLC) coupled with an ultraviolet (UV) detector
or electrochemical detector may be preferable. This method
describes the use of an electron capture detector.
3.3 Interferences resulting from analytes having similar retention
times during gas-liquid chromatography are resolved by improv-
ing the resolution or separation, such as by changing the
chromatographic column or operating parameters, or by frac-
tionating the sample by column chromatography.
3.4 Sampling procedure is also applicable to other pesticides
which may be determined by gas-liquid chromatography coupled
with a nitrogen-phosphorus detector (NPD), flame photometric
detector (FPD), Hall electrolytic conductivity detector (HECD),
or a mass spectrometer (MS).
-------
T010-3
4. Significance
4.1 Pesticide usage and environmental distribution are common to
rural and urban areas of the United States. The application
of pesticides can cause adverse health effects to humans by
contaminating soil, water, air, plants, and animal life.
4.2 Many pesticides exhibit bioaccumulative, chronic health effects;
therefore, monitoring the presence of these compounds in ambient
air is of great importance.
4.3 Use of a portable, low volume PUF sampling system allows the
user flexibility in locating the apparatus. The user can
place the apparatus in a stationary or mobile location.
The portable sampling apparatus may be positioned in a vertical
or horizontal stationary location (if necessary, accompanied
with supporting structure). Mobile positioning of the
system can be accomplished by attaching the apparatus to a
person to test air in the individual's breathing zone.
Moreover, the PUF cartridge used in this method provides for
successful collection of most pesticides.
5. Definitions
Definitions used in this document and in any user-prepared Standard
Operating Procedures (SOPs) should be consistent with ASTM D1356,
D1605-60, E260, and E355. All abbreviations and symbols are defined
within this document at point of use.
5.1 Sampling efficiency (SE) - ability of the sampling medium to trap
vapors of interest. %SE is the percentage of the analyte of in-
terest collected and retained by the sampling medium when it is
introduced as a vapor in air or nitrogen into the air sampler and
the sampler- is operated under normal conditions for a period of
time equal to or greater than that required for the intended use.
5.2 Retention efficiency (RE) - ability of sampling medium to retain
a compound added (spiked) to it in liquid solution.
5.2.1 Static retention efficiency - ability of the sampling
medium to retain the solution spike when the
sampling cartridge is stored under clean, quiescent
conditions for the duration of the test period.
-------
T010-4
5.2.2 Dyjnami^retention efficiency - ab 111 ty of the sampl 1 ng
medium to retain the solution spike when air or nit-
rogen is drawn through the sampling cartridge under
normal operating conditions for the duration of the
test period. The dynamic RE is normally equal to or
less than the SE.
5.3 Retention time (RT) - time to elute a specific chemical from
a chromatographic column. For a specific carrier gas flow rate,
RT is measured from the time the chemical is injected into the
gas stream until it appears at the detector.
5'4 Relative retention time (RRT) - a ratio of RTs for two chemi-
cals for the same chromatographic column and carrier gas flow
rate, where the denominator represents a reference chemical.
6. Interferences
6.1 Any gas or liquid chromatographic separation of complex mix-
tures of organic chemicals is subject to serious interference
problems due to coelution of two or more compounds. The use
of capillary or narrowbore columns with superior resolution
and/or two or more columns of different polarity will
frequently eliminate these problems.
6.2 The electron capture detector responds to a wide variety of
organic compounds. It is likely that such compounds will be
encountered as interferences during 6C/ECD analysis. The NPD,
FPD, and HECD detectors are element specific, but are still
subject to interferences. UV detectors for HPLC are nearly
universal, and the electrochemical detector may also respond to
a variety of chemicals. Mass spectrometric analyses will gene-
rally provide positive identification of specific compounds.
6.3 Certain organochlorine pesticides (£.£., chlordane) are complex
mixtures of individual compounds that can make difficult
accurate quantification of a particular formulation in a multiple
component mixture. Polychlorinated biphenyls (PCBs) may inter-
fere with the determination of pesticides.
-------
T010-5
6.4 Contamination of glassware and sampling apparatus with traces
of pesticides can be a major source of error, particularly at
lower analyte concentrations. Careful attention to cleaning
and handling procedures is required during all steps of sampling
and analysis to minimize this source of error.
6.5 The general approaches listed below should be followed to
minimize interferences.
6.5.1 Polar compounds, including certain pesticides (£.£•.
organophosphorus and carbamate classes), can be removed
by column chromatography on alumina. This sample clean-
up will permit analysis of most organochlorine pesticides.
6.5.2 PCBs may be separated from other organochlorine
pesticides by column chromatography on silicic
acid.
6.5.3 Many pesticides can be fractionated into groups by column
chromatography on Florisil (Floridin Corp.).
7. Apparatus
7.1 Continuous-flow sampling pump (Figure 1) - (DuPont Alpha-1
Air Sampler, E.I. DuPont de Nemours & Co., Inc., Wilimington,
DE, 19898, or equivalent).
7.2 Sampling cartridge (Figure 2) - constructed from a 20 mm (i.d.)
x 10 cm borosilicate glass tube drawn down to a 7 mm (o.d.)
open connection for attachment to the pump via Tygon tubing
(Norton Co., P.O. Box 350, Akron, OH, 44309, or equivalent).
The cartridge can be fabricated inexpensively from glass by
Kontes (P.O. Box 729,'Vlneland, NJ, 08360), or equivalent.
7.3 Sorbent, polyurethane foam (PUF) - cut into a cylinder, 22 mm
in diameter and 7.6 cm long, fitted under slight compression
inside the cartridge. The PUF should be of the polyether type,
(density No. 3014 or 0.0225 g/cm3) used for furniture upholstery,
pillows, and mattresses; it may be obtained from Olympic Products
Co. (Greensboro, NC), or equivalent source. The PUF cylinders
(plugs) should be slightly larger in diameter than the internal
diameter of the cartridge. They may be cut by one of the
following means:
-------
T010-6
With a high-speed cutting tool, such as a motorized
cork borer. Distilled water should be used to lub-
ricate the cutting tool.
With a hot wire cutter. Care should be exercised
to prevent thermal degradation of the foam.
With scissors, while plugs are compressed between
the 22 mm circular templates.
Alternatively, pre-extracted PUF plugs and glass cartridges
may be obtained commercially (Supelco, Inc., Supelco Park,
Bellefonte, PA, 16823, No. 2-0557, or equivalent).
7.4 Gas chromatograph (GC) with an electron capture detector (ECD)
and either an isothermally controlled or temperature-programmed
heating oven. The analytical system should be complete with all
required accessories including syringes, analytical columns,
gases, detector, and strip chart recorder. A data system is
recommended for measuring peak heights. Consult EPA Method 608
for additional specifications.
7.5 Gas chromatographic column, such as 4- or 2-mm (i.d.) x 183 cm
borosilicate glass packed with 1.5% SP-2250 (Supelco, Inc.)/1.95%
SP-2401 (Supelco, Inc.) on 100/120 mesh Supelcoport (Supelco,
Inc.), 4% SE-30 (General Electric, 50 Fordham Rd., Wilmington, MA,
01887, or equivalent)/6% OV-210 (Ohio Valley Specialty Chemical,
115 Industry Rd., Marietta, OH, 45750, or equivalent) on 100/200
mesh Gas Chrom Q (Alltec Assoc., Applied Science Labs, 2051
Waukegan Rd, Deerfield, IL, 60015, or equivalent), 3% OV-101
(Ohio Valley Specialty Chemical ) on UltraBond (Ultra Scientific,
1 Main St., Hope, RI, 02831, or equivalent) and 3% OV-1 (Ohio
Valley Specialty Chemical) on 80/100 mesh Chromosorb WHP
(Manville, Filtration, and Materials, P.O. Box 5108, Denver
CO, 80271, or equivalent). Capillary GC column, such as 0.32
mm (i.d.) x 30 m DB-5 (J&W Scientific, 3871 Security Park Dr.,
Rancho Cordova, CA, 95670, or equivalent) with 0.25 urn film thick-
ness. HPLC column, such as 4.6 mm x 25 cm Zorbax SIL (DuPont
Co., Concord Plaza, Wilmington, DE, 19898, or equivalent) or
u-Bondapak C-18 (Millipore Corp., 80 Ashby Rd., Bedfore, MA,
01730, or equivalent).
7.6 Microsyringes - 5 uL volume or other appropriate sizes.
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T010-7
8. Reagents and Materials
[Note: For a detailed listing of various other items required for
extract preparation, cleanup, and analysis, consult U.S. Method 608
which is provided in Appendix A of Method TO-4 in the Compendium.]
8.1 Round bottom flasks, 500 ml, I 24/40 joints.
8.2 Soxhlet extractors, 300 ml, with reflux condensers.
8.3 Kuderna-Danish concentrator apparatus, 500 ml, with Snyder
columns.
8.4 Graduated concentrator tubes, 10 ml, with J 19/22 stoppers
(Kontes, P.O. Box 729, Vineland, NJ, 08360, Cat. No. K-570050,
size 1025, or equivalent).
8.5 Graduated concentrator tubes, 1 mL, with I 14/20 stoppers
(Kontes, Vineland, NJ, Cat. No. K-570050, size 0124, or
equivalent).
8.6 TFE fluorocarbon tape, 1/2 in.
8.7 Filter tubes, size 40 mm (i.d.) x 80 mm, (Corning Glass Works,
Science Products, Houghton Park, AB-1, Corning, NY, 14831, Cat.
No. 9480, or equivalent).
8.8 Serum vials, 1 ml and 5 mL, fitted with caps lined with TFE
fluorocarbon.
8.9 Pasteur pipettes, 9 in.
8.10 Glass wool fired at 500°C.
8.11 Boiling chips fired at 500°C.
8.12 Forceps, stainless steel, 12 in.
8.13 Gloves, latex or precleaned (5% ether/hexane Soxhlet extracted)
cotton.
8.14 Steam bath.
8.15 Heating mantles, 500 mL.
8.16 Analytical evaporator, nitrogen blow-down (N-EvapCii), Organomation
Assoc., P.O. Box 159, South Berlin, MA, 01549, or equivalent).
8.17 Acetone, pesticide quality.
8.18 n-Hexane, pesticide quality.
8.19 Diethyl ether preserved with 2% ethanol (Mallinckrodt, Inc.,
Science Products Division, P.O. Box 5840, St. Louis, MO, 63134,
Cat. No. 0850, or equivalent).
8.20 Sodium sulfate, anhydrous analytical grade.
8.21 Alumina, activity grade IV, 100/200 mesh.
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T010-8
8.22 Glass chronatographic column (2 mm i.d. x 15 cm long).
8.23 Soxhlet extraction system, including Soxhlet extractors
(500 and 300 ml), variable voltage transformers, and
cooling water source.
8.24 Vacuum oven connected to water aspirator.
8.25 Die.
8.26 Ice chest.
8.27 Silicic acid, pesticide quality.
8.28 Octachloronaphthalene (OCN), research grade, (Ultra Scien-
tific, Inc., 1 Main St., Hope, RI, 02831, or equivalent).
8.29 Florisil (Floridin Corp.).
Assembly and Calibration of Sampling System
9.1 Description of Sampling Apparatus
9.1.1 The entire sampling system is diagrammed in Figure 1.
This apparatus was developed to operate at a rate of
1-5 L/minute and is used by U.S. EPA for low volume
sampling of ambient air. The method writeup presents
the use of this device.
9.1.2 The sampling module (Figure 2) consists of a glass
sampling cartridge in which the PUF plug is retained.
9.2 Calibration of Sampling System
9.2.1 Air flow through the sampling system is calibrated by
the assembly shown in Figure 3. The air sampler must
be calibrated in the laboratory before and after each
sample collection period, using the procedure described
below.
9.2.2 For accurate calibration, attach the sampling cartridge
in-line during calibration. Vinyl bubble tubing (Fisher
Scientific, 711 Forbes Ave., Pittsburgh, PA, 15219, Cat.
No. 14-170-132, or equivalent) or other means (£.£.,
rubber stopper or glass joint) may be used to connect
the large end of the cartridge to the calibration system.
Refer to ASTM Standard Practice D3686, Annex A2 or
Standard Practice D4185, Annex Al for procedures to
calibrate small volume air pumps.
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T010-9
10. Preparation of Sampling (PUF) Cartridges
10.1 The PUF adsorbent is white and yellows upon exposure to light.
10.2 For initial cleanup and quality assurance purposes, the PUF
plug is placed in a Soxhlet extractor and extracted with ace-
tone for 14 to 24 hours at 4 to 6 cycles per hour (If commer-
cially pre-extracted PUF plugs are used, extraction with ace-
tone is not required.). This procedure is followed by a 16-hour
Soxhlet extraction with 5% diethyl ether in n-hexane. When
cartridges are reused, 5% ether in n-hexane can be used as the
cleanup solvent.
10.3 The extracted PUF is placed in a vacuum oven connected to a
water aspirator and dried at room temperature for 2 to 4 hours
(until no solvent odor is detected). The clean PUF is placed in
labeled glass sampling cartridges using gloves and forceps. The
cartridges are wrapped with hexane-rinsed aluminum foil and
placed in glass jars fitted with TFE fluorocarbon-lined caps.
The foil wrapping may also be marked for identification using
a blunt probe.
10.4 At least one assembled cartridge from each batch should be an-
alyzed as a laboratory blank before any samples are analyzed.
A blank level of <10 ng/plug for single component compounds is
considered to be acceptable. For multiple component mixtures,
the blank level should be <100 ng/plug.
11. Sampling
11.1 After the sampling system has been assembled and calibrated as
per Section 9, it can be used to collect air samples as described
below.
11.2 The prepared sample cartridges should be used within 30 days of
loading and should be handled only with latex or precleaned
cotton gloves.
11.3 The clean sample cartridge is carefully removed from the alumi-
num foil wrapping (the foil is returned to jars for later use)
and attached to the pump with flexible tubing. The sampling
assembly is positioned with the intake downward or horizontally.
The sampler is located in an unobstructed area at least 30 cm
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T010-10
from any obstacle to air flow. The PUF cartridge intake is
positioned 1 to 2 m above ground level. Cartridge height above
ground is recorded on the Sampling Data Form shown in Figure 4.
11.4 After the PUF cartridge is correctly inserted and positioned,
the power switch is turned on and the sampling begins. The
elapsed time meter is activated and the start time is recorded.
The pumps are checked during the sampling process and any
abnormal conditions discovered are recorded on the data sheet.
Ambient temperatures and barometric pressures are measured and
recorded periodically during the sampling procedure.
11.5 At the end of the desired sampling period, the power is turned
off and the PUF cartridges are wrapped with the original alumi-
num foil and placed in sealed, labeled containers for transport
back to the laboratory. At least one field blank is returned
to the laboratory with each group of samples. A field blank
is treated exactly like a sample except that no air is drawn
through the cartridge. Samples are stored at -10°C or below
until analyzed.
12. Sample Preparation, Cleanup, and Analysis
[Note: Sample preparation should be preformed under a properly
ventilated hood.]
12.1 Sample Preparation
12.1.1 All samples should be extracted within 1 week after
col lection.
12.1.2 All glassware is washed with a suitable detergent;
rinsed with deionized water, acetone, and hexane;
rinsed again with deionized water; and fired in an
oven (450°C).
12.1.3 Sample extraction efficiency is determined by spik-
ing the samples with a known solution. Octachloro-
naphthalene (OCN) is an appropriate standard to use
for pesticide analysis using GC/ECD techniques. The
spiking solution is prepared by dissolving 10 mg of
OCN in 10 ml of 10% acetone in n-hexane, followed by
serial dilution with n-hexane to achieve a final
concentration of 1 ug/mL.
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T010-11
12.1.4 The extracting solution (5% ether/hexane) is prepared
by mixing 1900 mL of freshly opened hexane and 100 ml
of freshly opened ethyl ether (preserved with ethanol)
to a flask.
12.1.5 All clean glassware, forceps, and other equipment to
be used are placed on rinsed (5% ether/hexane) aluminum
foil until use. The forceps are also rinsed with 5%
ether/hexane. The condensing towers are rinsed with
5% ether/hexane and 300 ml are added to a 500 ml round
bottom boiling flask.
12.1.6 Using precleaned (£.£., 5% ether/hexane Soxhlet extracted)
cotton gloves, the PDF cartridges are removed from the
sealed container and the PDF is placed into a 300
ml Soxhlet extractor using prerinsed forceps.
12.1.7 Before extraction begins, 100 uL of the OCN solution
are added directly to the top of the PUF plug. Addition
of the standard demonstrates extraction efficiency of the
Soxhlet procedure. [Note: Incorporating a known concen-
tration of the solution onto the sample provides a quality
assurance check to determine recovery efficiency of the
extraction and analytical processes.]
12.1.8 The Soxhlet extractor is then connected to the 500 ml
boiling flask and condenser. The glass joints of the
assembly are wet with 5% ether/hexane to ensure a tight
seal between the fittings. If necessary, the PUF plug
can be adjusted using forceps to wedge it midway along
the length of the siphon. The above procedure should
be followed for all samples, with the inclusion of a
blank control sample.
12.1.9 The water flow to the condenser towers of the Soxhlet
extraction assembly is checked and the heating unit is
turned on. As the samples boil, the Soxhlet extractors
are inspected to ensure that they are filling and siphon-
ing properly (4 to 6 cycles/hour). Samples should cycle
for a minimum of 16 hours.
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T010-12
12.1.10 At the end of the extracting process, the heating units
are turned off and the samples are cooled to room temper-
ature.
12.1.11 The extracts are concentrated to a 5 mL solution using a
Kuderna-Danish (K-D) apparatus. The K-D is set up and
assembled with concentrator tubes. This assembly is
rinsed. The lower end of the filter tube is packed with
glass wool and filled with sodium sulfate to a depth of
40 mm. The filter tube is placed in the neck of the K-D.
The Soxhlet extractors and boiling flasks are carefully
removed from the condenser towers and the remaining sol-
vent is drained into each boiling flask. Sample extract
is carefully poured through the filter tube into the K-D.
Each boiling flask is rinsed three times by swirling hex-
ane along the sides. Once the sample has drained, the
filter tube is rinsed down with hexane. Each Synder column
is attached to the K-D and rinsed to wet the joint for a
tight seal. The complete K-D apparatus is placed on a
steam bath and the sample is evaporated to approximately
5 mL. The sample is removed from the steam bath and
allowed to cool. Each Synder column is rinsed with a
minimum of hexane. Sample volume is adjusted to 10 ml
in a concentrator tube, which is then closed with a glass
stopper and sealed with TFE fluorocarbon tape. Alterna-
tively, the sample may be quantitatively transferred (with
concentrator tube rinsing) to prescored vials and brought
up to final volume. Concentrated extracts are stored
at -10°C until analyzed. Analysis should occur no later
than two weeks after sample extraction.
12.2 Sample Cleanup
12.2.1 If only organochlorine pesticides are sought, an alumina
cleanup procedure is appropriate. Before cleanup, the
sample extract is carefully reduced to 1 ml using a
gentle stream of clean nitrogen.
12.2.2 A glass chromatographic column (2 mm i.d. x 15 cm long)
is packed with alumina, activity grade IV, and rinsed with
approximately 20 ml of n-hexane. The concentrated sample
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T010-13
extract is placed on the column and eluted with 10 ml of
n-hexane at a rate of 0.5 mL/minute. The eluate volume
is adjusted to exactly 10 mL and analyzed as per 12.3.
12.2.3 If other pesticides are sought, alternate cleanup pro-
cedures may be required (e^.£., Florisil). EPA Method 608
identifies appropriate cleanup procedures.
12.3 Sample Analysis
12.3.1 Organochlorine pesticides and many nonchlorinated pesti-
cides are responsive to electron capture detection
(Table 1). Most of these compounds can be determined at
concentrations of 1 to 50 ng/mL by 6C/ECD.
12.3.2 An appropriate GC column is selected for analysis of the
extract. (For example, 4 mm i.d. x 183 cm glass, packed
with 1.5% SP-2250/1.95% SP-2401 on 100/120 mesh Supelo-
port, 200°C isothermal, with 5% methane/95% argon carrier
gas at 65 to 85 mL/min). A chromatogram showing a mix-
ture containing single component pesticides determined
by GC/ECD using a packed column is shown in Figure 5.
A table of corresponding chromatographic characteristics
follows in Figure 6.
12.3.3 A standard solution is prepared from reference materials
of known purity. Standards of organochlorine pesticides
may be obtained from the National Bureau of Standards
and from the U.S. EPA.
12.3.4 Stock standard solutions (1.00 ug/uL) are prepared by
dissolving approximately 10 milligrams of pure material
in isooctane and diluting to volume in a 10 mL volu-
metric flask. Larger volumes can be used at the con-
venience of the analyst. If compound purity is cer-
tified at 96% or greater, the weight can be used with-
out correction to calculate the concentration of the
stock standard. Commerically prepared stock standards
may be used at any concentration if they are certified
by the manufacturer or an independent source.
12.3.5 The prepared stock standard solutions are transferred
to Teflon-sealed screw-capped bottles and stored at -10°C
for no longer than six months. The standard solutions
should be inspected frequently for signs of degradation
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T010-14
or evaporation (especially before preparing calibration
standards from them). [Note: Quality control check
standards used to determine accuracy of the calibration
standards are available from the U.S. Environmental
Protection Agency, Environmental Monitoring and Support
Laboratory, Cincinnati, Ohio 45268.]
12.3.6 The standard solutions of the various compounds of
interest are used to determine relative retention
times (RRTs) to an internal standard such as j3,j3'-DDE,
aldrin, or OCN.
12.3.7 Before analysis, the GC column is made sensitive to the
pesticide samples by injecting a standard pesticide solu-
tion ten (10) times more concentrated than the stock
standard solution. Detector linearity is then determined
by injecting standard solutions of three different concen-
trations that bracket the required range of analyses.
12.3.8 The GC system is calibrated daily with a minimum of
three injections of calibrated standards. Consult EPA
Method 608, Section 7 for a detailed procedure to
calibrate the gas chromatograph.
12.3.9 If refrigerated, the sample extract is removed from the
cooling unit and allowed to warm to room temperature. The
sample extract is injected into the GC for analysis in
an aliquot of approximately 2-6 uL using the solvent-
flush technique (Ref. D3687, 8.1.4.3-8.1.4.5). The actual
volume injected is recorded to the nearest 0.05 uL. After
GC injection, the sample's response from the strip chart
is analyzed by measuring peak heights or determining peak
areas. Ideally, the peak heights should be 20 to 80% of
full scale deflection. Using injections of 2 to 6 uL of
each calibration standard, the peak height or area re-
sponses are tabulated against the mass injected (injec-
tions of 2, 4, and 6 uL are recommended). If the response
(peak height or area) exceeds the linear range of detec-
tion, the extract is diluted and reanalyzed.
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T010-15
12.3.10 Pesticide mixtures are quantified by comparison of the
total heights or areas of GC peaks with the correspond-
ing peaks in the best-matching standard. If both PCBs
and organochlorine pesticides are present in the same
sample, column chromatographic separation on silicic
acid is used before GC analysis, according to ASTM
Standards, Vol. 14.01. If polar compounds that interfere
with GC/ECD analysis are present, column chromatographic
cleanup on alumina (activity grade IV) is used as per
Section 12.2.2.
12.3.11 For confirmation, a second GC column is used such as
4% SE-30/6% OV-210 on 100/200 mesh Gas Chrom Q or 3%
OV-1 on 80/100 mesh Chromosorb WHP. For improved re-
solution, a capillary column is used such as 0.32 mm
(i.d.) x 30 m DB-5 with 0.25 urn film thickness.
12.3.12 A chromatogram of a mixture containing single component
pesticides determined by GC/ECD using a capillary column
is shown in Figure 7. A table of the corresponding
chromatographic characteristics follows in Figure 8.
12.3.13 Class separation and improved specificity can be achieved
by column chromatographic separation on Florisil as per
EPA Method 608. For improved specificity, a Hall
electrolytic conductivity detector operated in the
reductive mode may be substituted for the electron
capture detector. Limits of detection will be reduced
by at least an order of magnitude, however.
13. GC Calibration
Appropriate calibration procedures are identified in EPA Method 608,
Section 7.
14. Calculations
14.1 The concentration of the analyte in the extract solution is
taken from a standard curve where peak height or area is
plotted linearly against concentration in nanograms per mini-
liter (ng/mL). If the detector response is known to be linear,
a single point is used as a calculation constant.
14.2 From the standard curve, determine the ng of analyte standard
equivalent to the peak height or area for a particular compound.
-------
T010-16
14.3 Determine if the field blank is contaminated. Blank levels
should not exceed 10 ng/sample for organochlorine pesticides
or 100 ng/sample for other pesticides. If the blank has been
contaminated, the sampling series must be held suspect.
14.4 Quantity of the compound in the sample (A) is calculated
using the following equation:
A = 1000
where:
A = total amount of analyte in the sample (ng).
As = calculated amount of material (ng) injected onto the
chromatograph based on calibration curve for injected
standards.
Ve = final volume of extract (ml).
V-j = volume of extract injected (uL).
1000 = factor for converting microliters to milliliters.
14.5 The extraction efficiency (EE) is determined from the recovery
of octachl oronaphthal ene (OCN) spike as follows:
EE(%) = S_ x 100
Sa
where:
S = amount of spike (ng) recovered.
Sa = amount of spike (ng) added to plug.
14.6 The total amount of nanograms found in the sample is corrected
for extraction efficiency and laboratory blank as follows:
where:
AC = corrected amount of analyte in sample (ng).
A0 = amount of analyte in blank (ng).
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T010-17
14.7 The total volume of air sampled under ambient conditions is
determined using the following equation:
x (T x F)
1000 L/m3
where:
Va = total volume of air sampled (nr).
T-J = length of sampling segment (min) between flow checks.
F-J = average flow (L/min) during sampling segment.
14.8 The air volume is corrected to 25° and 760 mm Hg (STP) as
follows:
/ Ph - Pw \ -/29_8J<\
\ 760 mm Hg/ \ t& /
where:
o
Vs = volume of air (m ) at standard conditions.
Va = total volume of air sampled (m3).
Pb = average ambient barometric pressure (mm Hg).
Pw = vapor pressure of water (mm Hg) at calibration temperature.
t/\ = average ambient temperature (K).
14.9 If the proper criteria for a sample have been met, concentration
of the compound in a cubic meter of air is calculated as follows:
ng/m3 = . A,, x 100
"vf "SET*)
where:
SE = sampling efficiency as determined by the procedure out-
lined in Section 15.
If it is desired to convert the air concentration value to parts
per trillion (wt/wt) in dry air at STP, the following conversion
is used:
ppt = 1.205 ng/m3
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T010-18
The air concentration is converted to parts per trillion (v/v) in
air at STP as follows:
k45 /ng/m3 \
I MW J
pptv = 24.
where:
MW = molecular weight of the compound of interest.
15. Sampling and Retention Efficiencies
15.1 Before using this procedure, the user should determine the sam-
pling efficiency for the compound of interest. The sampling
efficiencies shown in Tables 2 and 3 were determined for approxi-
mately 1 m3 of air at about 25°C, sampled at 3.8 L/min. Sampling
efficiencies for the pesticides shown in Table 4 are for 24 hours
at 3.8 L/min and 25°C. For compounds not listed, longer sampling
times, different flow rates, or other air temperatures, the fol-
lowing procedure may be used to determine sampling efficiencies.
15.2 SE is determined by a modified impinger assembly attached to the
sampler pump (Figure 9). Clean PUF is placed in the pre-fliter
location and the inlet is attached to a nitrogen line. [Note:
Nitrogen should be used instead of air to prevent oxidation of
the compounds under test. The oxidation would not necessarily
reflect what may be encountered during actual sampling and may
give misleading sampling efficiencies.] PUF plugs (22 mm x 7.6
cm) are placed in the primary and secondary traps and are atta-
ched to the pump.
15.3 A standard solution of the compound of interest is prepared
in a volatile solvent (e_.£., hexane, pentane, or benzene). A
small, accurately measured volume (£.£., 1 ml) of the standard
solution is placed into the modified midget impinger. The
sampler pump is set at the rate to be used in field application
and then activated. Nitrogen is drawn through the assembly for
a period of time equal to or exceeding that intended for field
application. After the desired sampling test period, the PUF
plugs are removed and analyzed separately as per Section 12.3.
15.4 The impinger is rinsed with hexane or another suitable solvent
and quantitatively transferred to a volumetric flask or concen-
trator tube for analysis.
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T010-19
15.5 The sampling efficiency (SE) is determined using the following
equation:
% SE = HT x 100
where:
WQ -
Wj = amount of compound extracted from the primary trap (rig).
W0 = original amount of compound added to the impinger (ng).
Wr = residue left in the impinger at the end of the test (ng)
15.6 If material is found in the secondary trap, it is an indication
that breakthrough has occurred. The addition of the amount found
in the secondary trap, W2, to Wi, will provide an indication of
the overall sampling efficiency of a tandem-trap sampling system.
The sum of Wj_, ^2 (if any)» and wr must eW^ (approximately +_
10%) W0 or the test is invalid.
15.7 If the compound of interest is not sufficiently volatile to vapo-
rize at room temperature, the impinger may be heated in a water
bath or other suitable heater to a maximum of 50°C to aid volati-
lization. If the compound of interest cannot be vaporized at
50°C or without thermal degradation, dynamic retention efficiency
(REd) may be used to estimate sampling efficiency. Dynamic re-
tention efficiency is determined in the manner described in 15.80
Table 5 lists those organochlorine pesticides which dynamic re-
tention efficiencies have been determined.
15.8 A pair of PUF plugs is spiked by slow, dropwise addition of the
standard solution to one end of each plug. No more than 0.5 to
1 ml of solution should be used. Amounts added to each plug
should be as nearly the same as possible. The plugs are allowed
to dry for 2 hours in a clean, protected place (e_._g_., dessicator).
One spiked plug is placed in the primary trap so that the spiked
end is at the intake and one clean unspiked plug is placed in the
secondary trap. The other spiked plug is wrapped in hexane-rinsed
aluminum foil and stored in a clean place for the duration of the
test (this is the static control plug, Section 15.9). Prefiltered
nitrogen or ambient air is drawn through the assembly as per
Section 15.3. [Note: Impinger may be discarded.] Each PUF
plug (spiked and static control) is analyzed separately as per
Section 12.3.
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T010-20
15.9 % REj) is calculated as follows:
Ml x 100
% REd = ~Ro
where:
MI = amount of compound (ng) recovered from primary plug.
W0 = amount of compound (ng) added to primary plug.
If a residue, W2, is found on the secondary plug, breakthrough
has occurred. The sum of Wj + W2 must equal W0, within 25% or
the test is invalid. For most compounds tested by this proce-
dure, % RE,j values are generally less than % SE values determined
per Section 15.1. The purpose of the static RE^ determination
is to establish any loss or gain of analyte unrelated to the
flow of nitrogen or air through the PUF plug.
16. Performance Criteria and Quality Assurance
This section summarizes required quality assurance (QA) measures
and provides guidance concerning performance criteria that should
be achieved within each laboratory.
16.1 Standard Operating Procedures (SOPs)
16.1.1 Users should generate SOPs describing the following
activities accomplished in their laboratory:
(1) assembly, calibration, and operation of the
sampling system, with make and model of equipment used;
(2) preparation, purification, storage, and
handling of sampling cartridges, (3) assembly,
calibration, and operation of the GC/ECD system,
with make and model of equipment used; and (4) all
aspects of data recording and processing, including
lists of computer hardware and software used.
16.1.2 SOPs should provide specific stepwise instructions and
should be readily available to, and understood by, the
laboratory personnel conducting the work.
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T010-21
16.2 Process, Field, and Solvent Blanks
16.2.1 One PUF cartridge from each batch of approximately twenty
should be analyzed, without shipment to the field, for
the compounds of interest to serve as a process blank.
16.2.2 During each sampling episode, at least one PUF cartridge
should be shipped to the field and returned, without draw-
ing air through the sampler, to serve as a field blank.
16.2.3 Before each sampling episode, one PUF plug from each
batch of approximately twenty should be spiked with a
known amount of the standard solution. The spiked
plug will remain in a sealed container and will not be
used during the sampling peroid. The spiked plug is
extracted and analyzed with the other samples. This
field spike acts as a quality assurance check to
determine matrix spike recoveries and to indicate sample
degradation.
16.2.4 During the analysis of each batch of samples, at least
one solvent process blank (all steps conducted but no
PUF cartridge included) should be carried through the
procedure and analyzed.
16.2.5 Blank levels should not exceed 10 ng/sample for single
components or 100 ng/sample for multiple component mix-
tures (£•£., for organochlorine pesticides).
16.3 Sampling Efficiency and Spike Recovery
16.3.1 Before using the method for sample analysis, each labo-
ratory must determine its sampling efficiency for the
component of interest as per Section 15.
16.3.2 The PUF in the sampler is replaced with a hexane-extracted
PUF. The PUF is spiked with a microgram level of compounds
of interest by dropwise addition of hexane solutions of
the compounds. The solvent is allowed to evaporate.
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T010-22
16.3.3 The sampling system is activated and set at the desired
sampling flow rate. The sample flow is monitored for
24 hours.
16.3.4 The PUF cartridge is then removed and analyzed as per
Section 12.3.
16.3.5 A second sample, unspiked, is collected over the same
time period to account for any background levels of
components in the ambient air matrix.
16.3.6 In general, analytical recoveries and collection effi-
ciencies of 75% are considered to be acceptable method
performance.
16.3.7 Replicate (at least triplicate) determinations of col-
lection efficiency should be made. Relative standard
deviations for these replicate determinations of +15%
or less are considered acceptable performance.
16.3.8 Blind spiked samples should be included with sample sets
periodically as a check on analytical performance.
16.4 Method Precision and Accuracy
16.4.1 Several different parameters involved in both the samp-
ling and analysis steps of this method collectively
determine the accuracy with which each compound is detected,
As the volume of air sampled is increased, the sensitivity
of detection increases proportionately within limits set
by (a) the retention efficiency for each specific com-
ponent trapped on the polyurethane foam plug, and (b) the
background interference associated with the analysis of
each specific component at a given site sampled. The
accuracy of detection of samples recovered by extraction
depends on (a) the inherent response of the particular
GC detector used in the determinative step, and (b) the
extent to which the sample is concentrated for analysis.
It is the responsibility of the analyst(s) performing the
sampling and analysis steps to adjust parameters so that
the required detection limits can be obtained.
-------
T010-23
16.4.2 The reproducibility of this method has been determined to
range from +5 to ^30% (measured as the relative stan-
dard deviation) when replicate sampling cartridges are
used (N>5). Sample recoveries for individual compounds
generally fall within the range of 90 to 110%, but
recoveries ranging from 75 to 115% are considered accept-
able. PUF alone may give lower recoveries for more vola-
tile compounds (e_.£., those with saturation vapor pres-
sures >10-3 mm Hg). In those cases, another sorbent or
a combination of PUF and Tenax GC should be employed.
16.5 Method Safety
This procedure may involve hazardous materials, operations, and
equipment. This method does not purport to address all of the
safety problems associated with Us use. It is the users
responsibility to consult and establish appropriate safety and
health practices and determine the applicability of regulatory
limitations prior to the Implementation of this procedure.
This should be part of the users SOP manual.
-------
T010-24
TABLE 1. PESTICIDES DETERMINED BY
GAS CHROMATOGRAPHY/ELECTRON CAPTURE DETECTOR (GC/ECD)
Aldrin
BHC (a - and 0-Hexa-
chlorocyclohexanes)
Captan
Chlordane, technical
Chlorothalonll
Chlorpyrifos
2,4,-D esters
£,£,-DDT
£,£,-DDE
Dieldrin
Dlchlorvos (DDVP)
Dicofol
Endrin
Endrin aldehyde
Folpet
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Lindane (y-BHC)
Methoxychlor
Mexacarbate
Mi rex
trans-Nonachlor
Oxychlordane
Pentachlorobenzene
Pentachlorophenol
Ronnel
2,4,5-Trichlorophenol
-------
T010-25
TABLE 2. SAMPLING EFFICIENCIES FOR SOME ORGANOCHLORINE PESTICIDES
Compound
a-Hexachlorocyclo-
hexane (a-BHC)
y-Hexachlorocyclo-
hexane (Lindane)
Hexachlorobenzene *
Chlordane, technical
£,£' -DDT
£,£'-DDE
Mi rex
Pentachlorobenzene *
Pentachlorophenol
2,4,5-Trichlorophenol
2,4-D Esters:
isopropyl
butyl
i sobutyl
i sooctyl
Quantity
Introduced, ug
0.005
0.05-1.0
0.5, 1.0
0.2
0.6, 1.2
0.2, 0.4
0.6, 1.2
1.0
1.0
t 1.0
0.5
0.5
0.5
0.5
,1 i • '-• "* !• —
Air
Volume,
m3
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
3.6
3.6
3.6
3.6
Sampling
Efficiency, %
mean RSD n
115
91.5
94.5
84.0
97.5
102
85.9
94
107
108
92.0
82.0
79.0
>80*
•.,.- - i
8 6 '
8 5
8 5
11 8
21 12
11 12
22 7
12 5
16 5
3 5
5 12
10 11
20 12
* Not vaporized. Value base on %RE = 81.0 (RSD = 10%, n = 6).
t Semi volatile organochlorine pesticides.
-------
T010-26
TABLE 3. SAMPLING EFFICIENCIES FOR ORGANOPHOSPHORUS PESTICIDES
Sampling
Quantity Efficiency, %
Compound Introduced,b ug mean RSD
Dichlorvos (DDVP)
Ronnel
Chlorpyrifos
Diazinon3
Methyl parathion3
Ethyl parathion3
Malathion3
0.2
0.2
0.2
1.0
0.6
0.3
0.3
72.0
106
108
84.0
80.0
75.9
100C
13
8
9
18
19
15
—
2
12
12
18
18
18
—
a Analyzed by gas chromatography with nitrogen phosphorus detector or
flame photometric detector.
b Air volume = 0.9 m^.
c Decomposed in generator; value based on %RE = 101
(RDS = 7, n = 4).
-------
T010-27
TABLE 4 EXTRACTION AND 24-HOUR SAMPLING EFFICIENCIES FOR VARIOUS
IWSLt <*. tA.KHo pESTICIDES m RELATED COMPOUNDS
Compound
Chlorpyrifos
Pentachlorophenol
Chi or dan e
Lindane
DDVP
2,4-D methyl ester
Heptachlor
Aldrin
Dieldrin
Ronnel
Diazinon
trans-Nonachl or
Oxychlordane
«-BHC
Chlorothalonil
Heptachlor epoxide
Extraction
Efficiency, *%
mean RSD
83.3 11.5
84.0 22.6
95.0 7.1
96.0 6.9
88.3 20.2
99.0 1.7
97.7 4.0
95.0 7.0
80.3 19.5
72.0 21.8
97.7 4.0
100.0 0.0
98.0 3.5
90.3 8.4
100.0 0.0
Sampling Efficiency, t %, at
10 ng/m3 100 ng/m-3 1000 ng/m-3
mean RSD mean RSD mean RSD
83.7 18.0 92.7
66.7 42.2 52.3
96.0 1.4 74.0
91.7 11.6 93.0
51.0 53.7 106.0
75.3 6.8 58.0
97.3 13.6 103.0
90.7 5.5 94.0
82.7 7.6 85.0
74.7 12.1 60.7
63.7 18.9 41.3
96.7 4.2 101.7
95.3 9.5 94.3
86.7 13.7 97.0
76.7 6.1 70.3
95.3 5.5 97.7
15.1 83.7
36.2 66.7
8.5 96.0
2.6 91.7
1.4 51.0
23.6 75.3
17.3 97.3
2.6 90.7
11.5 82.7
15.5 74.7
26.6 63.7
15.3 96.7
1.2 95.3
18.2 86.7
6.5 76.7
14.2 95.3
18.0
42.2
1.4
11.6
53.7
6.8
13.6
5.5
7.6
12.2
19.9
4.2
9.5
13.7
6.1
5.5
* Mean values for one spike at 550 ng/plug
t Mean values for three determinations.
and two spikes at 5500 ng/plug.
-------
T012-28
Table 5. EXTRACTION AND 24-HOUR SAMPLING EFFICIENCIES FOR VARIOUS
PESTICIDES AND RELATED COMPOUNDS
Compound
Dicofol
Captan
Methoxychlor
Folpet
Extraction Retention Efficiency, t %, at
Efficiency, *% 10 ng/m3 100 ng/m3 1000 ng/m3
mean RSD mean RSD mean RSD mean RSD
57-° 8-5 38.0 25.9 65.0 8.7 69.0
73-° 12-7 56.0 — 45.5 64.3 84.3 16.3
65'5 4-9 78.5 2.1
86-7 n-7 — — 78.0 — 93.0
* Mean Values for one spike at 550 ng/plug and two spikes at 5500 ng/plug.
t Mean Values for generally three determinations.
-------
T010-29
SAMPLING CARTRIDGE
115V ADAPTER/
CHARGER PLUG
FIGURE 1. LOW VOLUME AIR SAMPLER
-------
T010-30
fm^^^^^Wmimi^^^^-
FIGURE 2. POLYURETHANE FOAM (PUF) SAMPLING
CARTRIDGE
-------
T010-31
FLOW RATE
METER (0-1 in H20)
If
FLOWRATE
VALVE
)
x
y
500 mL
BUBBLE
TUBE
AIR IN
DISH WITH
BUBBLE SOLUTION
PRESSURE DROP
METER (0-50 in H20)
r™ ____ --------
VALVE
I
PUMP
FIGURE 3. CALIBRATION ASSEMBLY FOR AIR SAMPLER
PUMP
-------
yiiH . Date PPrfnrmrrl hv
Sampler
S/N
Sampling
Location
I.D.
Height
above
Ground
PUF Cart.
No.
Samplin
Start
Period
Stop
Sampling
Time min.
Pump Timer
hr. min.
Low flow
Indication
Yes Nn
Comments
o
I—'
o
I
CO
ro
Checked by_
Date
FIGURE 4. LOW VOLUME PESTICIDE SAMPLING DATA FORM
-------
T010-33
OPERATING CONDITIONS
Column Type: 1.5% SP 2250/1.95% SP 2401,
V4" glass.
Temperature: 200°C isothermal.
Detector: Electron Capture.
Carrier Gas: 5% Methane/95% Argon.
Flow Rate: 65 to 85 mL/min.
Lindane
Heptachlor
Aldrin
Dieldrin
Dibutylchlorendate
Methoxychlor
TIME
FIGURE 5. CHROMATOGRAM SHOWING A MIXTURE OF
SINGLE COMPONENT PESTICIDES DETERMINED BY
GC/ECD USING A PACKED COLUMN
-------
T010-34
EXTERNAL STANDARD TABLE
SINGLE COMPONENT PESTICIDE MIXTURE (5uL) ON
A PACKED COLUMN
RETENTION COMPOUND CONCENTRATION IN PG
TIME NAME ON COLUMN
2.77
3.37
4.03
8.90
10.72
14.63
24.87
26.82
gamma-BHC (Lindane)
Heptachlor
Aldrin
Dieldrin
Endrin
p.p'-DDT
Di butyl chlorendate*
Methoxychlor
500
500
500
500
500
500
2500
2500
AREA/
HEIGHT
8.2
10.4
12.0
24.7
30.2
39.0
61.4
57.5
Internal standard used for earlier pesticide detection.
FIGURE 6. CHROMATOGRAPHIC CHARACTERISTICS OF THE
SINGLE COMPONENT PESTICIDE MIXTURE
DETERMINED BY GC/ECD USING A
PACKED COLUMN
-------
T010-35
OPERATING CONDITIONS _
Column Type: DB-5 0.32 capillary,
0.25 urn film thickness
Column Temperature Program: 90°C (4 min)/16°C per min to
154°C/4°C per min to 270°C.
Detector: Electron Capture
Carrier Gas: Helium at 1 mL/min.
Make Up Gas: 5% Methane/95% Argon at 60 mL/min.
TIME
Heptachlor
Lindane
Dibutylchlorendate
Methoxychlor
Aldrin Endrjn
Dieldrin
FIGURE 7. CHROMATOGRAM SHOWING A MIXTURE OF
SINGLE COMPONENT PESTICIDES DETERMINED BY
GC/ECD USING A CAPILLARY COLUMN
-------
T010-36
EXTERNAL STANDARD TABLE
SINGLE COMPONENT PESTICIDE MIXTURE (2uL) ON
ON A CAPILLARY COLUMN
RETENTION
TIME
14.28
17.41
18.96
23.63
24.63
27.24
29.92
31.49
COMPOUND
NAME
CONCENTRATION
ON COLUMN
gamma-BHC (Lindane)
Heptachlor
Aldrin
Dieldrin
Endrin
p.p'-DDT
Methoxychlor
Di butyl chl orendate*
IN PG
200
200
200
200
200
200
1000
1000
AREA/
HEIGHT
5.2
5.3
5.4
*f * ~
5.8
6.3
5.6
5.5
5.4
* Internal standard used for earlier pesticide detection.
FIGURE 8. CHROMATOGRAPHIC CHARACTERISTICS OF THE
SINGLE COMPONENT PESTICIDE MIXTURE
DETERMINED BY GC/ECD USING A
CAPILLARY COLUMN
-------
AIR INLET
AIR TO PUMPING
SYSTEM
COLLECTION
MEDIUM
COLLECTION
MEDIUM
BACK-UP
CD
I—1
o
GO
FIGURE 9. APPARATUS FOR DETERMINING SAMPLING
EFFICIENCIES
-------
-------
Revision 1.0
June, 1987
METHOD T011
METHOD FOR THE DETERMINATION OF FORMALDEHYDE IN AMBIENT AIR
USING ADSORBENT CARTRIDGE FOLLOWED BY HIGH PERFORMANCE
LIQUID CHROMATOGRAPHY (HPLC)
1. Scope
1.1 This document describes a method for the determi nation of
formaldehyde in ambient air utilizing solid adsorbent fol-
lowed by high performance liquid chromatographic detection.
Formaldehyde has been found to be a major promoter in the
formation of photochemical ozone. In particular, short
term exposure to formaldehyde and other specific aldehydes
(acetaldehyde, acrolein, crotonaldehyde) is known to cause
irritation of the eyes, skin, and mucous membranes of the
upper respiratory tract.
1.2 Compendium Method T05, "Method For the Determination of
Aldehydes and Ketones in Ambient Air Using High Perform-
ance Liquid Chromatography (HPLC)" involves drawing
ambient air through a midget impinger sampling train con-
taining 10 mL of 2N HC1/0.05% 2,4-dinitrophenylhydrazine
(DNPH) reagent. Aldehydes and ketones readily form a stable
derivative with the DNPH reagent, and the DNPH derivative
is analyzed for aldehydes and ketones utilizing HPLC.
Method T011 modifies the sampling procedures outlined in
Method T05 by introducing a coated adsorbent for sampling
formaldehyde. This current method is based on the specific
reaction of organic carbonyl compounds (aldehydes and
ketones) with DNPH-coated cartridges in the presence of an
acid to form stable derivatives according to the following
equation:
N02 N02
R1
\ / \ H+ \ /\
C = 0 + H2N-NH—^ NV- NQ2 >- C = N-NH—(' /—N02 + H2°
CARBONYL GROUP 2.4-DINITROPHENYLHYDRAZINE nMpl. npmx/AT,.,p WATFR
(ALDEHYDES AND KETONES) (DNPH) DNPH-DERIVATIVE WATER
where R and R' are organic alkyl or aromatic group (ketones) or
either substituent is a hydrogen (aldehydes).
-------
T011-2
The determination of formaldehyde from the DNPH-formaldehyde
derivative is similar to Method T05 in incorporating HPLC.
The detection limits have been extended and other aldehydes
and ketones can be determined as outlined in Section 14.
1.3 The sampling method gives a time-weighted average (TWA) sample.
It can be used for long-term (1-24 hr) sampling of ambient air
where the concentration of formaldehyde is generally in the
low (1-20) ppb (v/v) or for short-term (5-60 min) sampling
of source-impacted atmospheres where the concentration of
formaldehyde could reach the ppm (v/v) levels.
1.4 The sampling flow rate, as described in this document, is
presently limited to about 1.5 L/min. This limitation is
principally due to the high pressure drop across the DNPH-
coated silica gel cartridges. Because of this, the procedure is
not compatible with pumps used in personal sampling equipments.
1.5 The method instructs the user to purchase Sep-PAK chromato-
graphic grade silica gel cartridges (Waters Associates,
34 Maple St., Mil ford, MA 01757) and apply acidified DNPH
in situ to each cartridge as part of the user-prepared
quality assurance program (1,2). Commercially pre-coated DNPH
cartridges are also available. [Caution: Recent studies
have indicated abnormally high formaldehyde background
levels in commercially prepacked cartridges. It is advised
that three cartridges randomly selected from each production
lot, be analyzed for formaldehyde prior to use to determine
acceptable levels.] Thermosorb/F cartridges (Thermedics,
Inc., 470 Wildwood St., P.O. Box 2999, Woburn, MA, 01888-1799)
can be purchased prepacked. The cartridges are 1.5 cm ID x
2 cm long polyethylene tubes with Luer®-type fittings on
each end. The adsorbent is composed of 60/80-mesh Florisil
(magnesium silicate) coated with 2,4-dinitrophenylhydrazine.
The adsorbent is held in place with 100 mesh stainless
steel screens at each end. The precoated cartridges are
used as received and are discarded after use. The cartridges
are stored in glass culture tubes with polypropylene caps
and placed in cold storage when not in use.
-------
T011-3
1.6 This method may involve hazardous materials, operations,
and equipments. This method does not purport to address
all the safety problems associated with its use. It is the
responsibility of whoever uses this method to consult and
establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
Applicable Documents
2.1 ASTM Standards
D1356 - Definition of Terms Relating to Atmospheric Sampling
and Analysis
E682 - Practice for Liquid Chromatography Terms and
Relationships
2.2 Other Documents
Existing Procedures (3-5)
Ambient Air Studies (6-8)
U. S. EPA Technical Assistance Document (9)
Indoor Air Studies (10-11)
Summary of Method
3.1 A known volume of ambient air is drawn through a prepacked
silica gel cartridge coated with acidified DNPH at a sampling
rate of 500-1200 mL/min for an appropriate period of time.
Sampling rate and time are dependent upon carbonyl concentra-
tion in the test atmosphere.
3.2 After sampling, the sample cartridges are capped and placed in
borosilicate glass culture tubes with polypropylene caps.
The capped tubes are then placed in a friction-top can con-
taining a pouch of charcoal and returned to the laboratory
for analysis. Alternatively, the sample vials can be placed
in a styrofoam box with appropriate padding for shipment to
the laboratory. The cartridges may either be placed in cold
storage until analysis or immediately washed by gravity
feed elution of 6 ml of acetonitrile from a plastic syringe
reservoir to a graduated test tube or a 5 ml volumetric flask.
3.3 The eluate is then topped to a known volume and refrigerated
until analysis.
3.4 The DNPH-formaldehyde derivative is determined using isocratic
reverse phase HPLC with an ultraviolet (UV) absorption detector
operated at 360 nm.
-------
T011-4
3.5 A cartridge blank is likewise desorbed and analyzed as per Sec-
tion 3.4.
3.6 Formaldehyde and other carbonyl compounds in the sample are iden-
tified and quantified by comparison of their retention times
and peak heights or peak areas with those of standard solutions.
Significance
4.1 Formaldehyde has been found to be a major promoter in the forma-
tion of photochemical ozone (12). In particular, short term ex-
posure to formaldehyde and other specific aldehydes (acetaldehyde,
acrolein, crotonaldehyde) is known to cause irritation of the
eyes, skin, and mucous membranes of the upper respiratory tract
(13). Animal studies indicate that high concentrations can in-
jure the lungs and other organs of the body (14). Formaldehyde
may contribute to eye irritation and unpleasant odors that are
common annoyances in polluted atmospheres.
4.2 Formaldehyde emissions result from incomplete combustion of hydro-
carbons and other organic materials. The major emission sources
appear to be vehicle exhaust, incineration of wastes, and burning
of fuels (natural gas, fuel oil, and coal). In addition, signifi-
cant amounts of atmospheric formaldehyde can result from photo-
chemical reactions between reactive hydrocarbons and nitrogen
oxides. Moreover, formaldehyde can react photochemically to pro-
duce other products, including ozone, peroxides, and peroxyacetyl
nitrate compounds. Local sources of formaldehyde may include
manufacturing and other industrial processes using the chemical.
In particular, formaldehyde emissions are associated with any
industrial process that results in the pyrolysis of organic
compounds in air or oxygen. This test method provides a means
to determine concentrations of formaldehyde and other carbonyl
compounds in emissions sources in various working environment
and in ambient indoor and outdoor atmospheres.
Definitions
5.1 Definitions used in this document and in any user-prepared Stan-
dard Operating Procedures (SOPs) should be consistent with ASTM
Methods D1356 and E682. All abbreviations and symbols within
this document are defined the first time they are used.
-------
T011-5
6. Interferences
6.1 This procedure has been written specifically for the sampling
and analysis of formaldehyde. Interferences in the method are
' certain isomeric aldehydes or ketones that may be unresolved by
the HPLC system when analyzing for other aldehydes and ketones.
Organic compounds that have the same retention time and signifi-
cant absorbance at 360 nm as the DNPH derivative of formaldehyde
will interfere. Such interferences can often be overcome by
altering the separation conditions (e.g., using alternative HPLC
columns or mobile phase compositions). However, other aldehydes
and ketones can be detected with a modification of the basic
procedure. In particular, chromatographic conditions can be
optimized to separate acrolein, acetone, and propionaldehyde
and the following higher molecular weight aldehydes and ketones
(within an analysis time of about one hour) by utilizing two
Zorbax ODS columns in series under a linear gradient program:
Formaldehyde Isovaleraldehyde
Acetaldehyde Valeraldehyde
Acrolein o-Tolualdehyde
Acetone m-Tolualdehyde
Propionaldehyde p-Tolualdehyde
Crotonaldehyde Hexanaldehyde
Butyraldehyde 2,5-Dimethylbenzaldehyde
Benzaldehyde
The linear gradient program varies the mobile phase composition
periodically to achieve maximum resolution of the C-3, C-4, and
benzaldehyde region of the chromatogram. The following gradient
program was found to be adequate to achieve this goal: Upon
sample injection, linear gradient from 60-75% acetonitrile/40-25%
water in 30 minutes, linear gradient from 75-100% acetonitrile/
25-0% water in 20 minutes, hold at 100% acetonitrile for 5 minutes,
reverse gradient to 60% acetonitrile/40% water in 1 minute, and
maintain isocratic at 60% acetonitrile/40% water for 15 minutes.
-------
T011-6
6.2 Formaldehyde contamination of the DNPH reagent is a frequently
encountered problem. The DNPH must be purified by multiple
recrystallizations in UV grade acetonitrile. Recrystalliza-
tion is accomplished at 40-60°C by slow evaporation of the
solvent to maximize crystal size. The purified DNPH crystals
are stored under UV grade acetonitrile until use. Impurity
levels of carbonyl compounds in the DNPH are determined by HPLC
prior to use and should be less than 0.025 ug/mL.
Apparatus
7.1 Isocratic HPLC system consisting of a mobile phase reservoir;
a high pressure pump; an injection valve (automatic sampler
with an optional 25-uL loop injector); a Zorbax ODS (DuPont
Instruments, Wilmington, DE), or equivalent C-18, reverse phase
(RP) column, or equivalent (25 cm x 4.6 mm ID); a variable
wavelength UV detector operating at 360 nm; and a data system
or strip chart recorder (Figure 1).
7.2 Sampling system - capable of accurately and precisely sampling
100-1500 mL/min of ambient air (Figure 2). The dry test meter
may not be accurate at flows below 500 mL/min, and should then
be replaced by recorded flow readings at the start, finish,
and hourly during the collection. The sample pump consists of
a diaphragm or metal bellows pump capable of extracting an air
sample between 500-1200 mL/min. [Note: A normal pressure drop
through the sample cartridge approaches 14 cm Hg at a sampling
rate of 1.5 L/min.]
7.3 Stopwatch.
7.4 Friction-top metal can (e.g., 1-gallon paint can) or a styrofoam
box with polyethlyene-air bubble padding - to hold sample vials.
7.5 Thermometer - to record ambient temperature.
7.6 Barometer (optional).
7.7 Suction filtration apparatus - for filtering HPLC mobile phase.
7.8 Volumetric flasks - various sizes, 5-2000 mL.
7.9 Pipets - various sizes, 1-50 mL.
7.10 Helium purge line (optional) - for degassing HPLC mobile phase.
7.11 Erlenmeyer flask, 1 L - for preparing HPLC mobile phase.
-------
T011-7
7.12 Graduated cylinder, 1 L - for preparing HPLC mobile phase.
7.13 Syringe, 100-250 uL - for HPLC injection.
7.14 Sample vials.
7.15 Melting point apparatus.
7.16 Rotameters.
7.17 Calibrated syringes.
7.18 Special glass apparatus for rinsing, storing and dispensing
saturated DNPH stock reagent (Figure 3).
7.19 Mass flow meters and mass flow controllers for metering/setting
air flow rate through sample cartridge of 500-1200 mL/min. [Note:
The mass flow controllers are necessary because cartridges
have a high pressure drop and at maximum flow rates, the
cartridge behaves like a "critical orifice." Recent studies
have shown that critical flow orifices may be used for 24-hour
sampling periods at a maximum rate of 1 L/min for atmospheres
not heavily loaded with particulates without any problems.]
7.20 Positive displacement, repetitive dispensing pipets (Lab-Indus-
tries, or equivalent), 0-10 mL range.
7.21 Cartridge drying manifold with multiple standard male Luer® con-
nectors.
7.22 Liquid syringes, 10 mL (polypropylene syringes are adequate) for
preparing DNPH-coated cartridges.
7.23 Syringe rack - made of an aluminum plate (0.16 x 36 x 53 cm)
with adjustable legs on four corners. A matrix (5 x 9) of cir-
cular holes of diameter slightly larger than the diameter of
the 10-mL syringes was symetrically drilled from the center of
the plate to enable batch processing of 45 cartridges for clean-
ing, coating, and/or sample elution.
7.24 Luer® fittings/plugs - to connect cartridges to sampling system
and to cap prepared cartridges.
7.25 Hot plates, beakers, flasks, measuring and disposable pipets,
volumetric flasks, etc. - used in the purification of DNPH.
7.26 Borosilicate glass culture tubes (20 mm x 125 mm) with polypro-
pylene screw caps - used to transport Sep-PAK coated cartridges
for field applications (Fisher Scientific, Pittsburgh, PA, or
equivalent).
7.27 Heated probe - necessary when ambient temperature to be sampled
is below 60°F to insure the effective collection of formaldehyde
as a hydrazone.
-------
T011-8
7.28 Cartridge sampler - prepacked silica gel cartridge, Sep-PAK
(Waters Associates, Mil ford, MA 01757, or equivalent) coated
in situ with DNPH according to Section 9.
7.29 Polyethylene gloves - used to handle Sep-PAK silica gel cart-
ridges, best source.
Reagents and Materials
8.1 2,4-Dinitrophenylhydrazine (DNPH)- Aldrich Chemical or J.T. Baker,
reagent grade or equivalent. Recrystallize at least twice
with UV grade acetonitrile before use.
8.2 Acetonitrile - UV grade, Burdick and Jackson "distilled-in-
glass," or equivalent.
8.3 Deionized-distilled water - charcoal filtered.
8.4 Perchloric acid - analytical grade, best source.
8.5 Hydrochloric acid - analytical grade, best source.
8.6 Formaldehyde - analytical grade, best source.
8.7 Aldehydes and ketones, analytical grade, best source - used
for preparation of DNPH derivative standards (optional).
8.8 Ethanol or methanol - analytical grade, best source.
8.9 Sep-PAK silica gel cartridge - Waters Associates, 34 Maple St.,
Mil ford, MA, 01757, or equivalent.
8.10 Nitrogen - high purity grade, best source.
8.11 Charcoal - granular, best source.
8.12 Helium - high purity grade, best source.
Preparation of Reagents and Cartridges
9.1 Purification of 2,4-Dinitrophenylhydrazine (DNPH)
[Note: This procedure should be performed under a properly
ventilated hood.]
9.1.1 Prepare a supersaturated solution of DNPH by boiling excess
DNPH in 200 mL of acetonitrile for approximately one hour.
9.1.2 After one hour, remove and transfer the supernatant to a
covered beaker on a hot plate and allow gradual cooling
to 40-60°C.
9.1.3 Maintain the solution at this temperature (40-60°C) until
95% of solvent has evaporated.
-------
T011-9
9.1.4 Decant solution to waste, and rinse crystals twice with
three times their apparent volume of acetonitrile. [Note:
Various health effects are resultant from the inhalation of
acetonitrile. At 500 ppm in air, brief inhalation has pro-
duced nose and throat irritation. At 160 ppm, inhalation
for 4 hours has caused flushing of the face (2 hour delay
after exposure) and bronchial tightness (5 hour delay).
Heavier exposures have produced systemic effects with
symptoms ranging from headache, nausea, and lassitude to
vomiting, chest or abdominal pain, respiratory depression,
extreme weakness, stupor, convulsions and death (dependent
upon concentration and time).]
9.1.5 Transfer crystals to another clean beaker, add 200 mL of
acetonitrile, heat to boiling, and again let crystals grow
slowly at 40-60°C until 95% of the solvent has evaporated.
9.1.6 Repeat rinsing process as described in Section 9.1.4.
9.1.7 Take an aliquot of the second rinse, dilute 10 times with
acetonitrile, acidify with 1 ml of 3.8 M perchloric acid
per 100 mL of DNPH solution, and analyze by HPLC.
9.1.8 The chromatogram illustrated in Figure 4 represents an
acceptable impurity level of <0.025 ug/mL of formaldehyde
in recrystallized DNPH reagent. An acceptable impurity
level for an intended sampling application may be defined
as the mass of the analyte (e.g. DNPH-formaldehyde deriva-
tive) in a unit volume of the reagent solution equivalent
to less than one tenth (0.1) the mass of the corresponding
analyte from a volume of an air sample when the carbonyl
(e.g. formaldehyde) is collected as DNPH derivative in an
equal unit volume of the reagent solution. An impurity
level unacceptable for a typical 10 L sample volume may
be acceptable if sample volume is increased to 100 L.
The impurity level of DNPH should be below the sensitivity
(ppb, v/v) level indicated in Table 1 for the anticipated
sample volume. If the impurity level is not acceptable
for intended sampling application, repeat recrystallization.
A special glass apparatus should be used for the final rinse
and storage according to the following procedure:
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T011-10
9.1.8.1 Transfer the crystals to the special glass appa-
ratus (Figure 3).
9.1.8.2 -Add about 25 mL of acetonitrile, agitate gently,
and let solution equilibrate for 10 minutes.
9.1.8.3 Drain the solution by properly positioning the
three-way stopcock. [Note: The purified crystals
should not be allowed to contact laboratory air
except for a brief moment. This is accomplished
by using the DNPH-coated silica cartridge on
the gas inlet of the special glass apparatus.]
9.1.8.4 After draining, turn stopcock so drain tube is
connected to measuring reservoir.
9.1.8.5 Introduce acetonitrile through measuring reservoir.
9.1.8.6 Rinsing should be repeated with 20-mL portions of
acetonitrile until a satisfactorily low impurity
level in the supernatant is confirmed by HPLC an-
alysis. An impurity level of <0.025 ug/mL formal-
dehyde should be achieved, as illustrated in
Figure 4.
9.1.9 If special glass apparatus is not available, transfer the
purified crystals to an all-glass reagent bottle, add
200 ml of acetonitrile, stopper, shake gently, and let
stand overnight. Analyze supernatant by HPLC according
to Section 11. The impurity level should be comparable
to that shown in Figure 4.
9.1.10 If the impurity level is not satisfactory, pipet off the
solution to waste, then add 25 mL of acetonitrile to the
purified crystals. Repeat Section 9.1.8.6.
9.1.11 If the impurity level is satisfactory, add another 25 mL
of acetonitrile, stopper and shake the reagent bottle,
then set aside. The saturated solution above the purified
crystals is the stock DNPH reagent.
9.1.12 After purification, purity of the DNPH reagent can be main-
tained by storing in the special glass apparatus.
9.1.13 Maintain only a minimum volume of saturated solution ade-
quate for day to day operation. This will minimize wastage
-------
T011-11
of purified reagent should it ever become necessary to re-
rinse the crystals to decrease the level of impurity for
applications requiring more stringent purity specifications,
9.1.14 Use clean pipets when removing saturated DNPH stock
solution for any analytical applications. Do not pour the
stock solution from the reagent bottle.
9.2 Preparation of DNPH-Formaldehyde Derivative
9.2.1 Titrate a saturated solution of DNPH in 2N HC1 with formal-
dehyde (other aldehydes or ketones may be used if their de-
tection is desirable).
9.2.2 Filter the colored precipitate, wash with 2N HC1 and water
and let precipitate air dry.
9.2.3 Check the purity of the DNPH-formaldehyde derivative by
melting point determination table or HPLC analysis. If
the impurity level is not acceptable, recrystallize the
derivative in ethanol. Repeat purity check and recrystal-
lization as necessary until acceptable level of purity
(e.g. 99%) is achieved.
9.3 Preparation of DNPH-Formaldehyde Standards
9.3.1 Prepare a standard stock solution of the DNPH-formal-
dehyde derivative by dissolving accurately weighed
amounts in acetonitrile.
9.3.2 Prepare a working calibration standard mix from the
standard stock solution. The concentration of the
DNPH-formaldehyde compound in the standard mix solutions
should be adjusted to reflect relative distribution
in a real sample. [Note: Individual stock solutions
of approximately 100 mg/L are prepared by dissolving
10 mg of the solid derivative in 100 ml of acetonitrile.
The individual solution is used to prepare calibra-
tion standards containing the derivative of interest
at concentrations of 0.5-20 ug/L, which spans the
concentration of interest for most ambient air work.]
9.3.3 Store all standard solutions in a refrigerator. They
should be stable for several months.
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9.4 Preparation of DNPH-Coated Sep-PAK Cartridges
[Note: This procedure must be performed in an atmosphere with a
very low aldehyde background. All glassware and plastic ware must
be scrupulously cleaned and rinsed with deionized water and alde-
hyde free acetonitrile. Contact of reagents with laboratory air
must be minimized. Polyethylene gloves must be worn when handl-
ing the cartridges.]
9.4.1 DNPH Coating Solution
9.4.1.1 Pipet 30 ml_ of saturated DNPH stock solution to a
1000 ml volumetric flask then add 500 mL acetonitrile.
9.4.1.2 Acidify with 1.0 ml of concentrated HC1. [Note:
The atmosphere above the acidified solution should
preferably be filtered through a DNPH-coated silica
gel cartridge to minimize contamination from labora-
tory air.] Shake solution then make up to volume
with acetonitrile. Stopper the flask, invert and
shake several times until the solution is homogeneous.
Transfer the acidified solution to a reagent bottle
with a 0-10 ml range positive displacement dispenser.
9.4.1.3 Prime the dispenser and slowly dispense 10-20 ml
to waste.
9.4.1.4 Dispense an aliquot solution to a sample vial,
and check the impurity level of the acidified
solution by HPLC according to Section 9.1 and
illustrated in Figure 4.
9.4.1.5 The impurity level should be <0.025 ug/mL
formaldehyde similar to that in the DNPH coating
solution.
9.4.2 Coating of Sep-PAK Cartridges
9.4.2.1 Open the Sep-PAK package, connect the short end
to a 10-mL syringe, and place it in the syringe
rack. [Note: Prepare as many cartridges and
syringes as possible.]
9.4.2.2 Using a positive displacement repetitive pipet,
add 10 ml of acetonitrile to each of the syringes.
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T011-13
9.4.2.3 Let liquid drain to waste by gravity. [Note:
Remove any air bubbles that may be trapped between
the syringe and the silica cartridge by displacing
them with the acetonitrile in the syringe.]
9.4.2.4 Set the repetitive dispenser containing the acidi-
fied DNPH coating solution to dispense 7 ml into
the cartridges.
9.4.2.5 Once the effluent flow at the outlet of the cart-
ridge has stopped, dispense 7 ml of the coating
reagent into each of the syringes.
9.4.2.6 Let the coating re'agent drain by gravity through
the cartridge until flow at the other end of the
cartridge stops.
9.4.2.7 Wipe the excess liquid at the outlet of each of
the cartridges with clean tissue paper.
9.4.2.8 Assemble a drying manifold with a scrubber or
"guard cartridge" connected to each of the
exit ports. These "guard cartridges" are
DNPH-coated and serve to remove any trace of
formaldehyde in the nitrogen gas supply.
9.4.2.9 Remove the cartridges from the syringes and con-
nect the short ends to the exit end of the scrub-
ber cartridge.
9.4.2.10 Pass nitrogen through each of the cartridges at
about 300-400 mL/min for 5-10 minutes.
9.4.2.11 Within 10 minutes of the drying process, rinse
the exterior surfaces and outlet ends of the car-
tridges with acetonitrile using a Pasteur pipet.
9.4.2.12 Stop the flow of nitrogen after 15 minutes and
insert cartridge connectors (flared at both
ends 0.25 OD x 1 in Teflon FEP tubing with ID
slightly smaller than the OD of the cartridge
port) to the long end of the scrubber cartridges.
9.4.2.13 Connect the short ends of a batch of the coated
cartridges to the scrubbers and pass nitrogen
at about 300-400 mL/min.
9.4.2.14 Follow procedure in Section 9.4.2.11.
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T011-14
9.4.2.15 After 15 minutes, stop the flow of nitrogen,
remove the dried cartridges and wipe the
cartridge exterior free of rinse acetonitrile.
9.4.2.16 Plug both ends of the coated cartridge with standard
polypropylene Luer® male plugs, place the plugged
cartridge in a borosilicate glass culture tube
with polypropylene screw caps.
9.4.2.17 Put a serial number and a lot number label on
each of the individual cartridge glass storage
container and store the prepared lot in the
refrigerator until use.
9.4.2.18 Store cartridges in an all-glass stoppered rea-
gent bottle in a refrigerator until use. [Note:
Plugged cartridges could also be placed in screw-
capped glass culture tubes and placed in a refrig-
erator until use.] Cartridges will maintain their
integrity for up to 90 days stored in refrigerated,
capped culture tubes.
9.4.2.19 Before transport, remove the glass-stoppered rea-
gent bottles (or screw-capped glass culture tubes)
containing the adsorbent tubes from the refriger-
ator and place the tubes individually in labeled
glass culture tubes. Place culture tubes in a
friction-top metal can containing 1-2 inches of
charcoal for shipment to sampling location.
9.4.2.20 As an alternative to friction-top cans for
transporting sample cartridges, the coated
cartridges could be shipped in their individual
glass containers. A big batch of coated
cartridges in individual glass containers may
be packed in a styrofoam box for shipment to the
field. The box should be padded with clean
tissue paper or polyethylene-air bubble padding.
Do not use polyurethane foam or newspaper as
padding material.
9.4.2.21 The cartridges should be immediately stored in a
refrigerator upon arrival in the field.
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T011-15
10. Sampling
10.1 The sampling system is assembled and should be similar
to that shown in Figure 2. [ Note: Figure 2(a) illustrates
a three tube/one pump configuration. The tester should
ensure that the pump is capable of constant flow rate
throughout the sampling period.] The coated cartridges
can be used as direct probes and traps for sampling
ambient air when the temperature is above freezing.
[Note: For sampling ambient air below freezing, a short
length (30-60 cm) of heated (50-60°C) stainless steel tubing
must be added to condition the air sample prior to
collection on adsorbent tubes.] Two types of sampling
systems are shown in Figure 2. For purposes of discussion,
the following procedure assumes the use of a dry test meter.
[Note: The dry test meter may not be accurate at flows
below 500 mL/min and should be backed up by recorded
flow readings at the start, finish, and hourly intervals
during sample collection.]
10.2 Before sample collection, the system is checked for leaks.
Plug the input end of the cartridge so no flow is indicated
at the output end of the pump. The mass flow meter should
not indicate any air flow through the sampling apparatus.
10.3 The entire assembly (including a "dummy" sampling cartridge)
is installed and the flow rate checked at a value near the
desired rate. In general, flow rates of 500-1200 mL/min
should be employed. The total moles of carbonyl in the
volume of air sampled should not exceed that of the DNPH
concentration ( 2 mg/cartridge). In general, a safe
estimate of the sample size should be 75% of the DNPH
loading of the cartridge. Generally, calibration is
accomplished using a soap bubble flow meter or calibrated
wet test meter connected to the flow exit, assuming the
system is sealed. [Note: ASTM Method 3686 describes an
appropriate calibration scheme that does not require a
sealed flow system downstream of the pump.]
-------
T011/-16
10.4 Ideally, a dry gas meter is included in the system to re-
cord total flow. If a dry gas meter is not available, the
operator must measure and record the sampling flow rate at
the beginning and end of the sampling period to determine
sample volume. If the sampling period exceeds two hours,
the flow rate should be measured at intermediate points
during the sampling period. Ideally, a rotameter should
be included to allow observation of the flow rate without
interruption of the sampling process.
10.5 Before sampling, remove the glass culture tube from the
friction-top metal can or styrofoam box. Let the cartridge
warm to ambient temperature in the glass tube before
connecting it to the sample train.
10.6 Using polyethylene gloves, remove the coated cartridge
from the glass tube and connect it to the sampling system
with a Luer® adapter fitting. Seal the glass tube for
later use, and connect the cartridge to the sampling train
so that its short end becomes the sample inlet. Record the
following parameters on the sampling data sheet (Figure 5):
date, sampling location, time, ambient temperature, baro-
metric pressure (if available), relative humidity (if avail-
able), dry gas meter reading (if appropriate), flow rate,
rotameter setting, cartridge batch number, and dry gas
meter pump identification numbers.
10.7 The sampler is turned on and the flow is adjusted to the
desired rate. A typical flow rate through one cartridge is
1.0 L/min and 0.8 L/min for two tandem cartridges.
10.8 The sampler is operated for the desired period, with peri-
odic recording of the variables listed above.
10.9 At the end of the sampling period, the parameters listed
in Section 10.6 are recorded and the sample flow is stopped.
If a dry gas meter is not used, the flow rate must be checked
at the end of the sampling interval. If the flow rates at
the beginning and end of the sampling period differ by more
than 15%, the sample should be marked as suspect.
-------
T011-17
10.10 Immediately after sampling, remove the cartridge (using
polyethylene gloves) from the sampling system, cap with
Luer* end plugs, and place it back In the original labeled
glass culture tube. Cap the culture tube, seal it with
Teflon* tape, and place it in a friction-top can contain-
ing 1-2 inches of granular charcoal or styrofoam box with
appropriate padding. Refrigerate the the culture tubes
until analysis. Refrigeration period prior to analysis
should not exceed 30 days. [Note: If samples are to be
shipped to a central laboratory for analysis, the duration
of the non-refrigerated period should be kept to a
minimum, preferably less than two days.]
10.11 If a dry gas meter or equivalent total flow indicator is
not used, the average sample flow rate must be calculated
according to the following equation:
• Ql + Q? + . . . QN
QA •
. . - • ' N'
where:
QA * average flow rate (mL/min).
Ql» Q2* • • • ON * fl°w rates determined at beginning, end,
and intermediate points during sampling.
N = number of points averaged.
10.12 The total flow rate is then calculated using the following
equation:
(T2 - TX) x QA
V«n - _
1000
where:
Vm - total volume (L) sampled at measured
temperature and pressure.
Tg « stop time (minutes).
TI » start time (minutes).
?2 - TI • total sampling time (minutes).
QA •» average flow rate (mL/min).
-------
T011-18
10.13 The total volume (Vs) at standard conditions, 25°C and
760 mm Hg, is calculated from the following equation:
vs = Vm x J>A x 298
760 173" + fA
where:
Vs = total sample volume (L) at 25°C and
760 mm Hg pressure.
Vm = total sample volume (L) at measured tem-
_ perature and pressure.
PA = average ambient pressure (mm Hg).
t/\ = average ambient temperature (°C).
11. Sample Analysis
11.1 Sample Preparation
11.1.1 The samples are returned to the laboratory in a friction-
top can containing 1-2 inches of granular charcoal and
stored in a refrigerator until analysis. Alternatively,
the samples may also be stored alone in their individual
glass containers. The time between sampling and
analysis should not exceed 30 days.
11.2 Sample Desorption
11.2.1 Remove the sample cartridge form the labeled culture tube.
Connect the sample cartridge (outlet end during sampling)
to a clean syringe. [Note: The liquid flow during desorp-
tion should be in the reverse direction of air flow during
sample collection.]
11.2.2 Place the cartridge/syringe in the syringe rack.
11.2.3 Backflush the cartridge (gravity feed) by passing 6 mL
of acetonitrile from the syringe through the cartridge
to a graduated test tube or to a 5-mL volumetric flask.
[Note: A dry cartridge has an acetonitrile holdup volume
slightly greater than 1 ml. The eluate flow may stop be-
fore the acetonitrile in the syringe is completely drained
into the cartridge because of air trapped between the car-
tridge filter and the syringe Luer® tip. If this happens,
displace the trapped air with the acetronitrile in the
syringe using a long-tip disposable Pasteur pipet.]
-------
T011-19
11.2.4 Dilute to the 5-mL mark with acetonitrile. Label the
flask with sample identification. Pipet two aliquots
into sample vials with Teflon-lined septa. Analyze
the first aliquot for the derivative carbonyls by HPLC.
Store the second aliquot in the refrigerator until
sample analysis.
11.3 HPLC Analysis
11.3.1 The HPLC system is assembled and calibrated as described
in Section 11.4. The operating parameters are as follows:
Column; Zorbax ODS (4.6 mm ID x 25 cm), or
equivalent.
Mobile Phase; 60% acetonitrile/40% water, isocratic.
Detector; ultraviolet, operating at 360 nm.
Flow Rate; 1.0 mL/min.
Retention Time: 7 minutes for formaldehyde with
one Zorbax ODS column.
13 minutes for formaldehyde with
two Zorbax ODS columns.
Sample Injection Volume; 25 uL.
Before each analysis, the detector baseline is checked
to ensure stable conditions.
11.3.2 The HPLC mobile phase is prepared by mixing 600 mL of
acetonitrile and 400 mL of water. This mixture is
filtered through a 0.22-um polyester membrane filter
in an all-glass and Teflon® suction filtration appa-
ratus. The filtered mobile phase is degassed by pur-
ging with helium for 10-15 minutes (100 mL/min) or
by heating to 60°C for 5-10 minutes in an Erlenmeyer
flask covered with a watch glass. A constant back
pressure restrictor (350 kPa) or short length (15-30 cm)
of 0.25 mm (0.01 inch) ID Teflon® tubing should be
placed after the detector to eliminate further mobile
phase outgassing.
11.3.3 The mobile phase is placed in the HPLC solvent reservoir
and the pump is set at a flow rate of 1.0 mL/min and
-------
T011-20
allowed to pump for 20-30 minutes before the first analy-
sis. The detector is switched on at least 30 minutes be^-
fore the first analysis, and the detector output is dis-
played on a strip chart recorder or similar output device.
11.3.4 A 100-uL aliquot of the sample is drawn into a clean HPLC
injection syringe. The sample injection loop (25 uL) is
loaded and an injection is made. The data system, if
available, is activated simultaneously with the injection,
and the point of injection is marked on the strip chart
recorder.
11.3.5 After approximately one minute, the injection valve is '
returned to the "inject" position and the syringe and
valve are rinsed or flushed with acetonitrile/water
mixture in preparation for the next sample analysis.
[Note: The flush/rinse solvent should not pass through
the sample loop during flushing.] The loop is clean
while the valve is in the "inject" mode.
11.3.6 After elution of the DNPH-formaldehyde derivative
(Figure 6), data acquisition is terminated and the
component concentrations are calculated as described
1n Section 12.
11.3.7 After a stable baseline is achieved, the system can be
used for further sample analyses as described above.
[Note: After several cartridge analyses, buildup on
the column may be removed by flushing with several
column volumes of 100% acetonitrile.]
11.3.8 If the concentration of analyte exceeds the linear range
of the instrument, the sample should be diluted with
mobile phase, or a smaller volume can be injected into
the HPLC.
11.3.9 If the retention time is not duplicated (+10%), as de-
termined by the calibration curve, the acetonitrile/water
ratio may be increased or decreased to obtain the correct
elution time. If the elution time is too long, increase
-------
T011-21
the ratio; if it is too short, decrease the ratio.
[Note: The chromatographic conditions described here
have been optimized for the detection of formaldehyde.
Analysts are advised to experiment with their HPLC
system to optimize chromatographic conditions for
their particular analytical needs.]
11.4 HPLC Calibration
11.4.1 Calibration standards are prepared in acetonitrile
from the DNPH-formaldehyde derivative. Individual
stock solutions of 100 mg/L are prepared by dissolving
10 mg of solid derivative in 100 ml of mobile phase.
These individual solutions are used to prepare calibration
standards at concentrations spanning the range of interest.
11.4.2 Each calibration standard (at least five levels) is
analyzed three times and area response is tabulated
against mass injected (Figure 7). All calibration
runs are performed as described for sample analyses
in Section 11.3. Using the UV detector, a linear
response range of approximately 0.05-20 ug/L should be
achieved for 25-uL injection volumes. The results may
be used to prepare a calibration curve, as illustrated
in Figure 8. Linear response is indicated where a
correlation coefficient of at least 0.999 for a linear
least-squares fit of the data (concentration versus
area response) is obtained. The retention times for
each analyte should agree within 2%.
11.4.3 Once linear response has been documented, an intermediate
concentration standard near the anticipated levels of
each component, but at least 10 times the detection
limit, should be chosen for daily calibration. The day
to day response for the various components should be
within 10% for analyte concentrations 1 ug/mL or greater
and within 15-20% for analyte concentrations near 0.5 ug/mL.
If greater variability is observed, recalibration may be
required or a new calibration curve must be developed
from fresh standards.
-------
T011-22
11.4.4 The response for each component in the daily calibra-
tion standard is used to calculate a response factor
according to the following equation:
where:
RFC = response factor (usually area counts)
for the component of interest in nano-
grams injected/response unit.
Cc = concentration (mg/L) of analyte in the
daily calibration standard.
Vj = volume (uL) of calibration standard injected
Rc = response (area counts) for analyte in
the calibration standard.
12. Calculations
12.1 The total mass of analyte (DNPH-formaldehyde) is calculated
for each sample using the following equation:
Wd = RFC x Rd x VE/VI
where:
Wd = total quantity of analyte (ug) in the sample.
RFC = response factor calculated in Section 11.4.4.
Rd = response (area counts or other response units)
for analyte in sample extract, blank corrected.
= [(As) (VD/VA) - (Ab)(vb/vs)]
where:
As = area counts, sample.
Ab = area counts, blank.
Vb = volume (ml), blank.'
Vs = volume (ml), sample.
VE = final volume (mL) of sample extract.
Vj = volume of extract (uL) injected into the HPLC
system.
VD = redilution volume (if sample was rediluted).
VA = aliquot used for redilution (if sample was
rediluted).
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T011-23
12.2 The concentration of formaldehyde in the original sample is cal-
culated from the following equation:
Wd
C = . x 1000
Vs)
where:
CA = concentration of analyte (ng/L) in the orig-
inal sample.
Wd = total quantity of analyte (ug) in sample, blank
corrected.
Vm = total sample volume (L) under ambient conditions
Vs = total sample volume (L) at 25°C and 760 mm Hg.
The analyte concentrations can be converted to ppbv using the
following equation:
CA (ppbv) = CA (ng/L) x 24.4
MWA
where:
CA(ppbv) = Concentration of analyte in parts per
billion by volume.
CA (ng/L) is calculated using Vs.
= .molecular weight of analyte.
13. Performance Criteria and Quality Assurance
This section summarizes required quality assurance measures and
provides guidance concerning performance criteria that should be
achieved within each laboratory.
13.1 Standard Operating Procedures (SOPs).
13.1.1 Users should generate SOPs describing the following
activities in their laboratory: (1) assembly, cali-
bration, and operation of the sampling system, with
make and model of equipment used; (2) preparation,
-------
T011-24
purification, storage, and handling of sampling reagent
and samples; (3) assembly, calibration, and operation
of the HPLC system, with make and model of equipment
used; and (4) all aspects of data recording and processing,
including lists of computer hardware and software used.
13.1.2 SOPs should provide specific stepwise instructions and
should be readily available to and understood by the
laboratory personnel conducting the work.
13.2 HPLC System Performance
13.2.1 The general appearance of the HPLC system should be
similar to that illustrated in Figure 1.
13.2.2 HPLC system efficiency is calculated according to the
following equation:
N
where:
N column efficiency (theoretical plates).
tr = retention time (seconds) of analyte.
Wi/g = width of component peak at half height
(seconds).
A column efficiency of >5,000 theoretical plates should
be obtained.
13.2.3 Precision of response for replicate HPLC injections should
be +10% or less, day to day, for analyte calibration
standards at 1 ug/mL or greater levels. At 0.5 ug/mL level
and below, precision of replicate analyses could vary up
to 25%. Precision of retention times should be ^2% on
a given day.
13.3 Process Blanks
13.3.1 At least one field blank or 10% of the field samples,
whichever is larger, should be shipped and analyzed with
each group of samples. The number of samples within a
-------
T011-25
group and/or time frame should be recorded so that a
specified percentage of blanks is obtained for a given
number of field samples. The field blank is treated
identically to the samples except that no air is drawn
through the cartridge. The performance criteria de-
scribed in Section 9.1 should be met for process blanks.
13.4 Method Precision and Accuracy
13.4.1 At least one duplicate sample or 10% of the field sam-
ples, whichever is larger, should be collected during
each sampling episode. Precision for field replication
should be _+20% or better.
13.4.2 Precision for replicate HPLC injections should be +10%
or better, day to day, for calibration standards.
13.4.3 At least one sample spike with analyte of interest or
10% of the field samples, whichever is larger, should
be collected.
13.4.4 Before initial use of the method, each laboratory should
generate triplicate spiked samples at a minimum of three
concentration levels, bracketing the range of interest
for each compound. Triplicate nonspiked samples must
also be processed. Spike recoveries of >80 _+ 10% and
blank levels as outlined in Section 9.1 should be
achieved.
14. Detection of other Aldehydes and Ketones
[Note: The procedure outlined above has been written specifically
for the sampling and analysis of formaldehyde in ambient air using
an adsorbent cartridge and HPLC. Ambient air contains other alde-
hydes and ketones. Optimizing chromatographic conditions by using two
Zorbax ODS columns in series and varying the mobile phase composition
through a gradient program will enable the analysis of other aldehydes
and ketones.]
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T011-26
14.1 Sampling Procedures
Same as Section 10.
14.2 HPLC Analysis
14.2.1 The HPLC system is assembled and calibrated as described
in Section 11. The operating parameters are as follows:
Column; Zorbax ODS, two columns in series
Mobile Phase: Acetonitrile/water, linear gradient
Step 1. 60-75% acetonitrile/40-25% water in 30
minutes.
Step 2. 75-100% acetonitrile/25-0% water in
20 minutes.
Step 3. 100% acetonitrile for 5 minutes.
Step 4. 60% acetonitrile/40% water reverse gra-
dient in 1 minute.
Step 5. 60% acetonitrile/40% water, isocratic, for
15 minutes.
Detector; Ultraviolet, operating at 360 nm
Flow Rate; 1.0 mL/min
Sample Injection Volume: 25 uL
14.2.2 The gradient program allows for optimization of chromato-
graphic conditions to separate acrolein, acetone,
propionaldehyde, and other higher molecular weight alde-
hydes and ketones in an analysis time of about one
hour. Table 1 illustrates the sensitivity for selective
aldehydes and ketones that have been identified using
two Zorbax ODS columns in series.
14.2.3 The chromatographic conditions described here have been
optimized for a gradient HPLC (Varian Model 5000) sys-
tem equipped with a UV detector (ISCO Model 1840 variable
wavelength), an automatic sampler with a 25-uL loop
injector and two DuPont Zorbax ODS columns (4.6 x 250
mm), a recorder, and an electronic integrator. Analysts
are advised to experiment with their HPLC systems to
optimize chromatographic conditions for their particular
analytical needs. Highest chromatographic resolution
and sensitivity are desirable but may not be achieved.
-------
T011-27
The separation of acrolein, acetone, and propionaldehyde
should be a minimum goal of the optimization.
14.2.4 The carbonyl compounds in the sample are identified and
quantified by comparing their retention times and area
counts with those of standard DNPH derivatives. Formal-
dehyde, acetaldehyde, acetone, propionaldehyde, croton-
aldehyde, benzaldehyde, and o-, m-, p-tolualdehydes can
be identified with a high degree of confidence. The
identification of butyraldehyde is less certain because
it coelutes with isobutyraldehyde and methyl ethyl
ketone under the stated chromatographic conditions.
Figure 10 illustrates a typical chromatogram obtained
with the gradient HPLC system.
14.2.5 The concentrations of individual carbonyl compounds are
determined as outlined in Section 12.
14.2.6 Performance criteria and quality assurance activities
should meet those requirements outlined in Section 13.
-------
T011-28
REFERENCES
S yestre B. Tejada, "Standard Operating Procedure For DNPH-coated
Silica Cartridges For Sampling Carbonyl Compounds In Air And Analysis
by High-performance Liquid Chromatography," Unpublished, U.S.
Environmental Protection Agency, Research Triangle Park, NC, March
19oo.
2. Silvestre B. Tejada, "Evaluation of Silica Gel Cartridges Coated in
|itu with Acidified 2,4-Dinitrophenylhydrazine for Sampling Aldehydes
and Ketones in Air", Intern. J. Environ. Anal. Chem.. 26:167-185, 1986.
3. Quality Assurance Handbook for Air Pollution Measurement Systems,
Volume ii - Ampient Air Specific Methods. LPA-bOQ/4-77-n?7AT n. s
Environmental Protection Agency, Research Triangle Park, NC, July
A .7 / y •
4. J. 0. Levin, et al., "Determination of Sub-part-per-Million Levels
of Formaldehyde in Air Using Active or Passive Sampling on 2,4-
Dinitrophenylhydrazine-Coated Glass Fiber Filters and High-Performance
Liquid Chromatography", Anal. Chem.. J57:1032-1035, 1985.
5* Compendium of Methods for the Determination of Toxic Organic Compounds
in Ambient Air. hPA-60Q/4-84-Q4i. n.s. Fnw^nn^n^i pr»tfct1on
Agency, Research Triangle Park, NC, April 1984.
6. J. E. Sigsby, Jr., et al., unpublished report on volatile organic
compound emissions from 46 in-use passenger cars, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 1984.
7. S. B. Tejada and W. D. Ray, unpublished results of study of aldehyde
concentration in indoor atmosphere of some residential homes, U.S.
Environmental Protection Agency, Research Triangle Park, NC, 1982.
8. J. M. Perez, F. Lipari, and D. E. Seizinger, "Cooperative Development
of Analytical Methods for Diesel Emissions and Particulates - Solvent
Extractions, Aldehydes and Sulfate Methods", presented at the Society
of Automotive Engineers International Congress and Exposition, Detroit,
MI, February-March 1984.
9. R. M. Riggin, Technical Assistance Document for Sampling and Analysis
of Toxic Organic Compounds in Ambient Air. EPA-600/4-83-Q27. U s
Environmental Protection Agency, Research Triangle Park, NC, June
1983.
10. E. V. Kring, et al., "Sampling for Formaldehyde in Workplace and
Ambient Air Environments - Additional Laboratory Validation and Field
Verification of a Passive Air Monitoring Device Compared with Conventional
Sampling Methods", J. Am. Ind. Hyg. Assoc.. 45:318-324, 1984.
-------
T011-29
11. I. Ahonen, E. Priha, and M-L Aijala, "Specificity of Analytical Methods
Used to Determine the Concentration of Formaldehyde in Workroom
Air", Chemosphere, 1_3:521-525, 1984.
12. J.J. Bufalini and K.L. Brulkker, "The Photooxidation of Formaldehyde
at Low Pressures." In: Chemical Reaction in Urban Atmospheres,
(ed. C.S. Tuesday), (American Elsevier Publishing Co., New York,
1971), pp. 225-240.
13. A.P. Altshuller and I.R. Cohen, Science 7, 1043 (1963).
14. Committee on Aldehydes, Board of Toxicology and Environmental Hazards,
•- "Formaldehyde and Other Aldehydes" (National
National Research Council,
Academy Press, Washington,
DC, 1981).
-------
Sample Volume, L
TABLE 1. SENSITIVITY (PPB.V/V) OF SAMPLING/ANALYSIS FOR
™.T ALDEHYDES AND KETONES IN AMBIENT AIR USING ADSORBENT
CARTRIDGE FOLLOWED BY GRADIENT HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
10
20
30
40
50
60
100 200 300 400 500 1000
Compound
Formaldehyde
Acet aldehyde
Acroleln
Acetone
Propionaldehyde
Crotonaldehyde
Butyraldehyde
Benzaldehyde
Isovaleraldehyde
Valeraldehyde
o-tolualdehyde
m-tolualdehyde
p-tolualdehyde
Hexanaldehyde
2,5-Dimethylbenzaldehyde
1.45
1.36
1.29
1.28
1.28
1.22
1.21
1.07
1.15
1.15
1.02
1.02
1.02
1.09
0.97
Sensiti
0.73
0.68
0.65
0.64
0.64
0.61
0.61
0.53
0.57
0.57
0.51
0.51
0.51
0.55
0.49
vity (ppb
0.48
0.45
0.43
0.43
0.43
0.41
0.40
0.36
0.38
0.38
0.34
0.34
0.34
0.36
0.32
, v/v)
0.36
0.34
0.32
0.32
0.32
0.31
0.30
0.27
0.29
0.29
0.25
0.25
0.25
0.27
0.24
of DNPH/HPLC
0.29 0.24
0.27 0.23
0.26 0.22
0.26 0.21
0.26 0.21
0.24 0.20
0.24 0.20
0.21 0.18
0.23 0.19
0.23 0.19
0.20 0.17
0.20 0.17
0.20 0.17
0.22 0.18
0.19 0.16
Method
0.15
0.14
0.13
0.13
0.13
0.12
0.12
0.11
0.11
0.11
0.10
0.10
0.10
0.11
0.10
Carbonyls
0.07 0.05
0.07 0.05
0.06 0.04
0.06 0.04
0.06 0.04
0.06 0.04
0.06 0.04
0.05 0.04
0.06 0.04
0.06 0.04
0.05 0.03
0.05 0.03
0.05 0.03
0.05 0.04
0.05 0.03
in Ambient Air
0.04 0.03 0.01
0.03 0.03 0.01
0.03 0.03 0.01
0.03 0.03 0.01
0.03 0.03 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.03 0.02 0.01
0.02 0.02 0.01
[Note: PPb values are measured at 1 atm and 25'C; sample cartridge is eluted with 5 mL
acetomtnle, and 25 mL are injected onto HPLC column.]
[Note: Maximum sampling flow through a DNPH-coated SEP-PAK is about 1.5 L per minute.]
I
CO
o
-------
INJECTION
VALVE
COLUMN
tr
VARIABLE
WAVELENGTH
UV
DETECTOR
MOBILE
PHASE
RESERVOIR
DATA
SYSTEM
STRIP CHART
RECORDER
CO
FIGURE 1. TYPICAL HPLC SYSTEM
-------
OIL-LESS
PUMP
VENT
TOll-32
MASS FLOW
CONTROLLERS
Couplings to
connect
DNPH-coated Sep-PAK
Adsorbent Cartridges
(a) MASS FLOW CONTROL
ROTAMETER
VENT
• . n
DRY
TEST
METER
=
i
•••
PUMP
••M
N
\
T
-*r=l
EEDLE
fALVE
(DRY TEST METER SHOULD NOT BE USED
FOR FLOW OF LESS THAN 500 ml/minute)
Coupling to
connect
DNPH-coated
Sep-PAK
Adsorbent
Cartridges
(b) NEEDLE VALVE/DRY TEST METER
FIGURE 2. TYPICAL SAMPLING SYSTEM CONFIGURATIONS
-------
T011-33
DNPH-COATED Si02
DNPH
CRYSTALS
HIGH-POROSITY
FRIT
THREE-WAY STOPCOCK
FIGURE 3.
SPECIAL GLASS APPARATUS FOR RINSING,
STORING, AND DISPENSING SATURATED
DNPH STOCK SOLUTION
-------
DNPH Reagent
Solvent Front
OJ
-p.
10
20
30
40
TIME, min
FIGURE 4. IMPURITY LEVEL OF DNPH
AFTER RECRYSTALLIZATION
50
-------
T011-35
PROJECT:
SITE:
SAMPLING DATA SHEET
(One Sample per Data Sheet)
DATE(S) SAMPLED:
LOCATION:
TIME PERIOD SAMPLED:_
OPERATOR:
INSTRUMENT MODEL NO:.
PUMP SERIAL NO:
CALIBRATED BY:
ADSORBENT CARTRIDGE INFORMATION:
Type:
Adsorbent:_
SAMPLING DATA:
Start Time:
Serial Number:_
Sample Number:"
Stop Time:
Time
Avg.
Dry Gas
Meter
Reading
Rotameter
Reading
*
Flow
Rate (Q)*f
mL/min
Ambient
Temperature,
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
Comments
* Flow rate from rotameter or soap bubble calibrator (specify which)
Total Volume Data (Vm) (use data from dry gas meter, if available)
Vm = (Final - Initial) Dry Gas Meter Reading, or = Liters
"m
or
Qi + Qz + Qs - • • QN
V = x 1
R1000 x (Sampling Time in Minutes)
'm
Liters
FIGURE 5.
EXAMPLE SAMPLING DATA SHEET
-------
T011-36
OPERATING PARAMETERS
HPLC
Column: Zorbax ODS or C-18 RP
Mobile Phase: 60% Acetonitrile/40% Water
Detector: Ultraviolet, operating at 360 nm
Flow Rate: 1 mL/min.
Retention Time: - 7 minutes for formaldehyde
Sample Injection Volume: 25 uL
z
c_
m
1
0
1 1 1
10
TIME, min
|
20
FIGURE 6.
CHROMATOGRAM OF DNPH-FORMALDEHYDE
DERIVATIVE
-------
T011-37
OPERATING PARAMETERS
HPLC
Column: Zorbax ODS or C-18 RP
Mobile Phase: 60°/o Acetonitrile/40% Water
Detector: Ulltraviolet, operating at 360 nm
Flow Rate: 1 mL/min.
.Retention Time: ~ 7 minutes for formaldehyde
Sample Injection Volume: 25 uL (a)
T
2 61 ug/mL
-3
T
6
TIME-*
m 1.23ug/mL
z
6.16ug/mL
CONC
.61 ug/mL
1.23 ug/mL
6.16ug/mL
12.32ug/mL
18.48ug/ml_
AREA
COUNTS
226541
452166
2257271
4711408
6953812
(d)
(e)
T
ts
LU
"3
T
TIME -> ^
12.32ug/mL yj
z
TIME-*
18.48ug/mL
FIGURE 7.
HPLC CHROMATOGRAM OF VARYING CON
CENTRATIONS OF DNPH-FORMALDEHYDE
DERIVATIVE
-------
T011-38
o
o
<
LU
OC
CORRELATION COEFFICIENT:
0.9999
OPERATING PARAMETERS
HPLC
Column: Zorbax ODS or C-18 RP
Mobile Phase: 60% Acetonitrile/40% Water
Detector: Ultraviolet, operating at 360 nm
Flow Rate: 1 mL/min
Retention Time: ~ 7 minutes for formaldehyde
Sample Injection Volume: 25 uL
3 6 9 12 15 18
DNPH-Formaldehyde Derivative (ug/mL)
FIGURE 8. CALIBRATION CURVE FOR FORMALDEHYDE
-------
Revision 1.0
June, 1987
METHOD T012
METHOD FOR THE DETERMINATION OF NON-METHANE ORGANIC COMPOUNDS (NMOC)
IN AMBIENT AIR USING CRYOGENIC PRECONCENTRATION AND DIRECT FLAME
IONIZATION DETECTION (PDFID)
1. Scope
1.1 In recent years, the relationship between ambient concentrations
of precursor organic compounds and subsequent downwind concentra-
tions of ozone has been described by a variety of photochemical
dispersion models. The most important application of such models
is to determine the degree of control of precursor organic com-
pounds that is necessary in an urban area to achieve compliance
with applicable ambient air quality standards for ozone (1,2).
1.2 The more elaborate theoretical models generally require detailed
organic species data obtained by multicomponent gas chromatography (3)
The Empirical Kinetic Modeling Approach (EKMA), however, requires
only the total non-methane organic compound (NMOC) concentration
data; specifically, the average total NMOC concentration from 6
a.m. to 9 a.m. daily at the sampling location. The use of total
NMOC concentration data in the EKMA substantially reduces the
cost and complexity of the sampling and analysis system by not
requiring qualitative and quantitative species identification.
1.3 Method T01, "Method for The Determination of Volatile Organic
Compounds in Ambient Air Using Tenax® Adsorption and Gas
Chromatography/Mass Spectrometry (GC/MS)", employs collection
of certain volatile organic compounds on Tenax® GC with subse-
quent analysis by thermal desorption/cryogenic preconcentration
and GC/MS identification. This method (T012) combines the same
type of cryogenic concentration technique used in Method T01
for high sensitivity with the simple flame ionization detector
(FID) of the GC for total NMOC measurements, without the GC
columns and complex procedures necessary for species separation.
-------
T012-2
1.4 In a flame ionization detector, the sample is injected into a
hydrogen-rich flame where the organic vapors burn producing
ionized molecular fragments. The resulting ion fragments are
then collected and detected. The FID is nearly a universal
detector. However, the detector response varies with the species
of [functional group in] the organic compound in an oxygen atmos-
phere. Because this method employs a helium or argon carrier
gas, the detector response is nearly one for all compounds.
Thus, the historical short-coming of the FID involving varying
detector response to different organic functional groups is
minimized.
1.5 The method can be used either for direct, in situ ambient
measurements or (more commonly) for analysis of integrated
samples collected in specially treated stainless steel canisters.
EKMA models generally require 3-hour integrated NMOC measurements
over the 6 a.m. to 9 a.m. period and are used by State or local
agencies to prepare State Implementation Plans (SIPs) for ozone
control to achieve compliance with the National Ambient Air
Quality Standards (NAAQS) for ozone. For direct, in situ ambient
measurements, the analyst must be present during the 6 a.m. to
9 a.m. period, and repeat measurements (approximately six per
hour) must be taken to obtain the 6 a.m. to 9 a.m. average
NMOC concentration. The use of sample canisters allows the
collection of integrated air samples over the 6 a.m. to 9 a.m.
period by unattended, automated samplers. This method has
incorporated both sampling approaches.
2. Applicable Documents
2.1 ASTM Standards
D1356 - Definition of Terms Related to Atmospheric
Sampling and Analysis
E260 - Recommended Practice for General Gas Chromato-
graphy Procedures
E355 - Practice for Gas Chromatography Terms and
Relationships
-------
T012-3
2.2 Other Documents
U. S. Environmental Protection Agency Technical Assistance
Documents (4,5)
Laboratory and Ambient Air Studies (6-10)
3. Summary of Method
3.1 A whole air sample is either extracted directly from the ambient
air and analyzed on site by the GC system or collected into a
precleaned sample canister and analyzed off site.
3.2 The analysis requires drawing a fixed-volume portion of the
sample air at a low flow rate through a glass-bead filled trap
that is cooled to approximately -186°C with liquid argon. The
cryogenic trap simultaneously collects and concentrates the
NMOC (either via condensation or adsorption) while allowing
the methane, nitrogen, oxygen, etc. to pass through the trap
without retention. The system is dynamically calibrated so
that the volume of sample passing through the trap does not
have to be quantitatively measured, but must be precisely
repeatable between the calibration and the analytical phases.
3.3 After the fixed-volume air sample has been drawn through the
trap, a helium carrier gas flow is diverted to pass through
the trap, in the opposite direction to the sample flow, and
into an FID. When the residual air and methane have been
flushed from the trap and the FID baseline restabilizes,
the cryogen is removed and the temperature of the trap is
raised to approximately 90°C.
3.4 The organic compounds previously collected in the trap revol-
atilize due to the increase in temperature and are carried into
the FID, resulting in a response peak or peaks from the FID.
The area of the peak or peaks is integrated, and the integrated
value is translated to concentration units via a previously-
obtained calibration curve relating integrated peak areas with
known concentrations of propane.
3.5 By convention, concentrations of NMOC are reported in units of
parts per million carbon (ppmC), which, for a specific compound,
is the concentration by volume (ppmV) multiplied by the number
of carbon atoms in the compound.
-------
T012-4
3.6 The cryogenic trap simultaneously concentrates the NMOC while
separating and removing the methane from air samples. The
technique is thus direct reading for NMOC and, because of
the concentration step, is more sensitive than conventional
continuous NMOC analyzers.
Significance
4.1 Accurate measurements of ambient concentrations of NMOC
are important for the control of photochemical smog because
these organic compounds are primary precursors of atmospheric
ozone and other oxidants. Achieving and maintaining compliance
with the NAAQS for ozone thus depends largely on control of
ambient levels of NMOC.
4.2 The NMOC concentrations typically found at urban sites may
range up to 5-7 ppmC or higher. In order to determine transport
of precursors into an area, measurement of NMOC upwind of the
area may be necessary. Upwind NMOC concentrations are likely
to be less than a few tenths of 1 ppm.
4.3 Conventional methods that depend on gas chromatography and
qualitative and quantitative species evaluation are excessively
difficult and expensive to operate and maintain when speciated
measurements are not needed. The method described here involves
a simple, cryogenic preconcentration procedure with subsequent,
direct, flame ionization detection. The method is sensitive and
provides accurate measurements of ambient NMOC concentrations
where speciated data are not required as applicable to the
EKMA.
Definitions
[Note: Definitions used in this document and in any user-prepared
Standard Operating Procedures (SOPs) should be consistent with ASTM
Methods D1356 and E355. All abbreviations and symbols are defined
within this document at point of use.]
-------
T012-5
5.1 Absolute pressure - Pressure measured with reference to absolute
zero pressure (as opposed to atmospheric pressure), usually ex-
Pressed as pounds-force per square inch absolute (psia).
5.2 Cryogen - A substance used to obtain very low trap temperatures
in the NMOC analysis system. Typical cryogens are liquid argon
(bp -185.7) and liquid oxygen (bp-183.0).
5.3 Dynamic calibration - Calibration of an analytical system with
pollutant concentrations that are generated in a dynamic, flow-
ing system, such as by quantitative, flow-rate dilution of a
high concentration gas standard with zero gas.
5.4 EKMA - Empirical Kinetics Modeling Approach; an empirical model
that attempts to relate morning ambient concentrations of non-
methane organic compounds (NMOC) and NOX with subsequent peak,
downwind ambient ozone concentrations; used by pollution control
agencies to estimate the degree of hydrocarbon emission reduction
needed to achieve compliance with national ambient air quality
standards for ozone.
5.5 Gauge pressure - Pressure measured with reference to atmospheric
pressure (as opposed to absolute pressure). Zero gauge pressure
(0 psig) is equal to atmospheric pressure, or 14.7 psia (101 kPa).
5.6 in situ - In place; in situ measurements are obtained by direct,
on-the-spot analysis, as opposed to subsequent, remote analysis
of a collected sample.
5.7 Integrated sample - A sample obtained uniformly over a specified
time period and representative of the average levels of pollutants
during the time period.
5.8 NMOC - Nonmethane organic compounds; total organic compounds as
measured by a flame ionization detector, excluding methane.
5.9 ppmC - Concentration unit of parts per million carbon; for a spe-
cific compound, ppmC is equivalent to parts per million by volume
(ppmv) multiplied by the number of carbon atoms in the compound.
5.10 Sampling - The process of withdrawing or isolating a representative
portion of an ambient atmosphere, with or without the simultaneous
isolation of selected components for subsequent analysis.
-------
T012-6
6. Interferences
6.1 In field and laboratory evaluation, water was found to cause a
positive shift in the FID baseline. The effect of this shift
is minimized by carefully selecting the integration termination
point and adjusted baseline used for calculating the area of
the NMOC peak(s).
6.2 When using helium as a carrier gas, FID response is quite
uniform for most hydrocarbon compounds, but the response can
vary considerably for other types of organic compounds.
7. Apparatus
7.1 Direct Air Sampling (Figure 1)
7.1.1 Sample manifold or sample inlet line - to bring
sample air into the analytical system.
7.1.2 Vacuum pump or blower - to draw sample air through a
sample manifold or long inlet line to reduce inlet
residence time. Maximum residence time should be no
greater than 1 minute.
7.2 Remote Sample Collection in Pressurized Canisters (Figure 2)
7.2.1 Sample canister(s) - stainless steel, Summa®-polished
vessel(s) of 4-6 L capacity (Scientific Instrumentation
Specialists, Inc., P.O. Box 8941, Moscow, ID 83843), used
for automatic collection of 3-hour integrated field
air samples. Each canister should have a unique identi-
fication number stamped on its frame.
7.2.2 Sample pump - stainless steel, metal bellows type
(Model MB-151, Metal Bellows Corp., 1075 Providence
Highway, Sharon, MA 02067) capable of 2 atmospheres
minimum output pressure. Pump must be free of leaks,
clean, and uncontaminated by oil or organic compounds.
7.2.3 Pressure gauge - 0-30 psig (0-240 kPa).
7.2.4 Solenoid valve - special electrically-operated, bistable
solenoid valve (Skinner Magnelatch Valve, New Britain}
-------
T012-7
CT), to control sample flow to the canister with negligi-
ble temperature rise (Figure 3). The use of the Skinner
Magnelatch valve avoids any substantial temperature rise
that would occur with a conventional, normally closed
solenoid valve, which would have to be energized during
the entire sample period. This temperature rise in the
valve could cause outgasing of organics from the Viton
valve seat material. The Skinner Magnelatch valve
requires only a brief electrical pulse to open or close
at the appropriate start and stop times and therefore
experiences no temperature increase. The pulses may
be obtained with an electronic timer that can be pro-
grammed for short (5 to 60 seconds) ON periods or with
a conventional mechanical timer and a special pulse
circuit. Figure 3 [a] illustrates a simple electrical
pulse circuit for operating the Skinner Magnelatch
solenoid valve with a conventional mechanical timer.
However, with this simple circuit, the valve may
operate unpredictably during brief power interruptions
or if the timer is manually switched on and off too
fast. A better circuit incorporating a time-delay
relay to provide more reliable valve operation is
shown in Figure 3[b].
7.2.5 Stainless steel orifice (or short capillary) - capable
of maintaining a substantially constant flow over the
sampling period (see Figure 4).
7.2.6 Particulate matter filter - 2 micron stainless steel
sintered in-line type (see Figure 4).
7.2.7 Timer - used for unattended sample collection. Capable
of controlling pump(s) and solenoid valve.
7.3 Sample Canister Cleaning (Figure 5)
7.3.1 Vacuum pump - capable of evacuating sample canister(s)
to an absolute pressure of <5 mm Hg.
7.3.2 Manifold - stainless steel manifold with connections
for simultaneously cleaning several canisters.
7.3.3 Shut off valve(s) - seven required.
7.3.4 Vacuum gauge - capable of measuring vacuum in the manifold
to an absolute pressure of 5 mm Hg or less.
-------
T012-8
7.3.5 Cryogenic trap (2 required) - U-shaped open tubular trap
cooled with liquid nitrogen or argon used to prevent con-
tamination from back diffusion of oil from vacuum pump,
and to provide clean, zero air to sample canister(s).
7.3.6 Pressure gauge - 0-50 psig (0-345 kPa), to monitor
zero ai r pressure.
7.3.7 Flow control valve - to regulate flow of zero air into
canister(s).
7.3.8 Humidifier - water bubbler or other system capable of
providing moisture to the zero air supply.
7.4 Analytical System (Figure 1)
7.4.1 FID detector system - including flow controls for the
FID fuel and air, temperature control for the FID, and
signal processing electronics. The FID burner air,
hydrogen, and helium carrier flow rates should be set
according to the manufacturer's instructions to obtain an
adequate FID response while maintaining as stable a flame
as possible throughout all phases of the analytical cycle.
7.4.2 Chart recorder - compatible with the FID output signal,
to record FID response.
7.4.3 Electronic integrator - capable of integrating the area
of one or more FID response peaks and calculating peak
area corrected for baseline drift. If a separate inte-
grator and chart recorder are used, care must be exer-
cised to be sure that these components do not interfere
with each other electrically. Range selector controls
on both the integrator and the FID analyzer may not pro-
vide accurate range ratios, so individual calibration
curves should be prepared for each range to be used.
The integrator should be capable of marking the beginning
and ending of peaks, constructing the appropriate base-
line between the start and end of the integration period,
and calculating the peak area.
-------
T012-9
Note: The FID (7.4.1), chart recorder (7.4.2), inte-
grator (7.4.3), valve heater (7.4.5), and a trap heat-
ing system are conveniently provided by a standard lab-
oratory chromatograph and associated integrator. EPA
has adapted two such systems for the PDFID method: a
Hewlett-Packard model 5880 (Hewlett-Packard Corp., Avon-
dale, PA) and a Shimadzu model GC8APF (Shimadzu Scientific
Instruments Inc., Columbia, MD; see Reference 5). Other
similar systems may also be applicable.
7.4.4 Trap - the trap should be carefully constructed from a
single piece of chromatographic-grade stainless steel
tubing (0.32 cm O.D, 0.21 cm I.D.) as shown in Figure 6.
The central portion of the trap (7-10 cm) is packed with
60/80 mesh glass beads, with small glass wool (dimethyldi-
chlorosilane-treated) plugs to retain the beads. The
trap must fit conveniently into the Dewar flask (7.4.9),
and the arms must be of an appropriate length to allow
the beaded portion of the trap'to be submerged below
the level of liquid cryogen in the Dewar. The trap should
connect directly to the six-port valve, if possible,
to minimize line length between the trap and the FID. The
trap must be mounted to allow the Dewar to be slipped
conveniently on and off the trap and also to facilitate
heating of the trap (see 7.4.13).
7.4.5 Six-port chromatographic valve - Seiscor Model VIII
(Seismograph Service Corp., Tulsa, OK), Valco Model 9110
(Valco Instruments Co., Houston, TX), or equivalent.
The six-port valve and as much of the interconnecting
tubing as practical should be located inside an oven or
otherwise heated to 80 - 90°C to minimize wall losses
or adsorption/desorption in the connecting tubing. All
lines should be as short as practical.
7.4.6 Multistage pressure regulators - standard two-stage,
stainless steel diaphram regulators with pressure gauges,
for helium, air, and hydrogen cylinders.
7.4.7 Pressure regulators - optional single stage, stainless
steel, with pressure gauge, if needed, to maintain
constant helium carrier and hydrogen flow rates.
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7.4.8 Fine needle valve - to adjust sample flow rate through
trap.
7.4.9 Dewar flask - to hold liquid cryogen to cool the trap,
sized to contain submerged portion of trap.
7.4.10 Absolute pressure gauge - 0-450 mm Hg,(2 mm Hg [scale
divisions indicating units]), to monitor repeatable
volumes of sample air through cryogenic trap (Wallace
and Tiernan, Model 61C-ID-0410, 25 Main Street, Belle-
ville, NJ).
7.4.11 Vacuum reservoir - 1-2 L capacity, typically 1 L.
7.4.12 Gas purifiers - gas scrubbers containing Drierite® or
silica gel and 5A molecular sieve to remove moisture
and organic impurities in the helium, air, and hydrogen
gas flows (Alltech Associates, Deerfield, IL). Note:
Check purity of gas purifiers prior to use by passing
zero-air through the unit and analyzing according to
Section 11.4. Gas purifiers are clean if produce
[contain] less than 0.02 ppmC hydrocarbons.
7.4.13 Trap heating system - chromatographic oven, hot water,
or other means to heat the trap to 80° to 90°C. A simple
heating source for the trap is a beaker or Dewar filled
with water maintained at 80-90°C. More repeatable types
of heat sources are recommended, including a temperature-
programmed chromatograph oven, electrical heating of
the trap itself, or any type of heater that brings the
temperature of the trap up to 80-90°C in 1-2 minutes.
7.4.14 Toggle shut-off valves (2) - leak free, for vacuum valve
and sample valve.
7.4.15 Vacuum pump - general purpose laboratory pump capable
of evacuating the vacuum reservoir to an appropriate
vacuum that allows the desired sample volume to be
drawn through the trap.
7.4.16 Vent - to keep the trap at atmospheric pressure during
trapping when using pressurized canisters.
7.4.17 Rotameter - to verify vent flow.
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7.4.18 Fine needle valve (optional) - to adjust flow rate of
sample from canister during analysis.
7.4.19 Chromatographic-grade stainless steel tubing (Alltech
Applied Science, 2051 Waukegan Road, Deerfield, IL, 60015,
(312) 948-8600) and stainless steel plumbing fittings -
for interconnections. All such materials in contact
with the sample, analyte, or support gases prior to
analysis should be stainless steel or other inert
metal. Do not use plastic or Teflon® tubing or fittings.
7.5 Commercially Available PDFID System (5)
7.5.1 A convenient and cost-effective modular PDFID system suit-
able for use with a conventional laboratory chromatograph
is commercially available (NuTech Corporation, Model 8548,
2806 Cheek Road, Durham, NC, 27704, (919) 682-0402).
7.5.2 This modular system contains almost all of the apparatus
items needed to convert the chromatograph into a PDFID
analytical system and has been designed to be readily
available and easy to assemble.
Reagents and Materials
8.1 Gas cylinders of helium and hydrogen - ultrahigh purity grade.
8.2 Combustion air - cylinder containing less than 0.02 ppm hydro-
carbons, or equivalent air source.
8.3 Propane calibration standard - cylinder containing 1-100 ppm
(3-300 ppmC) propane in air. The cylinder assay should be
traceable to a National Bureau of Standards (NBS) Standard Refer-
ence Material (SRM) or to a NBS/EPA-approved Certified Reference
Material (CRM).
8.4 Zero air - cylinder containing less than 0.02 ppmC hydrocar-
bons. Zero air may be obtained from a cylinder of zero-grade
compressed air scrubbed with Drierite® or silica gel and 5A
molecular sieve or activated charcoal, or by catalytic cleanup
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of ambient air. All zero air should be passed through a liquid
argon cold trap for final cleanup, then passed through a hyrdo-
carbon-free water bubbler (or other device) for humidification.
8.5 Liquid cryogen - liquid argon (bp -185.7°C) or liquid oxygen,
(bp -183°C) may be used as the cryogen. Experiments have shown
no differences in trapping efficiency between liquid argon and
liquid oxygen. However, appropriate safety precautions must be
taken if liquid oxygen is used. Liquid nitrogen (bp -195°C)
should not be used because it causes condensation of oxygen and
methane in the trap.
9. Direct Sampling
9.1 For direct ambient air sampling, the cryogenic trapping system
draws the air sample directly from a pump-ventilated distribution
manifold or sample line (see Figure 1). The connecting line should
be of small diameter (1/8" O.D.) stainless steel tubing and as
short as possible to minimize its dead volume.
9.2 Multiple analyses over the sampling period must be made to estab-
lish hourly or 3-hour NMOC concentration averages.
10. Sample Collection in Pressurized Canister(s)
For integrated pressurized canister sampling, ambient air is sampled
by a metal bellows pump through a critical orifice (to maintain
constant flow), and pressurized into a clean, evacuated, Summa®-
polished sample canister. The critical orifice size is chosen so
that the canister is pressurized to approximately one atmosphere above
ambient pressure, at a constant flow rate over the desired sample
period. Two canisters are connected in parallel for duplicate samples.
The canister(s) are then returned to the laboratory for analysis,
using the PDFID analytical system. Collection of ambient air samples
in pressurized canisters provides the following advantages:
o Convenient integration of ambient samples over a specific
time period
o Capability of remote sampling with subsequent central
laboratory analysis
o Ability to ship and store samples, if necessary
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o Unattended sample collection
o Analysis of samples from multiple sites with one analytical
system , ,
o Collection of replicate samples for assessment of measurement
precision
With canister sampling, however, great care must be exercised in
selecting, cleaning, and handling the sample canister(s) and sampling
apparatus to avoid losses or contamination of the samples.
10.1 Canister Cleanup and Preparation
10.1.1 All canisters must be clean and free of any contaminants
before sample collection.
10.1.2 Leak test all canisters by pressurizing them to approxi-
mately 30 psig [200 kPa (gauge)] with zero air. The
use of the canister cleaning system (see Figure 5) may
be adequate for this task. Measure the final pressure -
close the canister valve, then check the pressure after
24 hours. If leak tight, the pressure should not vary
more than +_ 2 psig over the 24-hour period. Note leak
check result on sampling data sheet, Figure 7.
10.1.3 Assemble a canister cleaning system, as illustrated in
Figure 5. Add cryogen to both the vacuum pump and zero
air supply traps. Connect the canister(s) to the mani-
fold. Open the vent shut off valve and the canister
valve(s) to release any remaining pressure in the canis-
ter. Now close the vent shut off valve and open the
vacuum shut off valve. Start the vacuum pump and evacuate
the canister(s) to <_ 5.0 mm Hg (for at least one hour).
[Note: On a daily basis or more often if necessary, blow-
out the cryogenic traps with zero air to remove any
trapped water from previous canister cleaning cycles.]
10.1.4 Close the vacuum and vacuum gauge shut off valves and
open the zero air shut off valve to pressurize the canis-
ter(s) with moist zero air to approximately 30 psig [200
kPa (gauge)]. If a zero gas generator system is used,
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the flow rate may need to be limited to maintain the
zero air quality.
10.1.5 Close the zero shut off valve and allow canister(s) to
vent down to atmospheric pressure through the vent shut
off valve. Close the vent shut off valve. Repeat steps
10.1.3 through 10.1.5 two additional times for a total of
three (3) evacuation/pressurization cycles for each set of
canisters.
10.1.6 As a "blank" check of the canister(s) and cleanup proce-
dure, analyze the final zero-air fill of 100% of the
canisters until the cleanup system and canisters are'
proven reliable. The check can then be reduced to a
lower percentage of canisters. Any canister that does
not test clean (compared to direct analysis of humidified
zero air of less than 0.02 ppmC) should not be utilized.
10.1.7 The canister is then re-evacuated to £ 5.0 mm Hg, using
the canister cleaning system, and remains in this con-
dition until use. Close the canister valve, remove the
canister from the canister cleaning system and cap
canister connection with a stainless steel fitting. The
canister is now ready for collection of an air sample.
Attach an identification tag to the neck of each
canister for field notes and chain-of-custody purposes.
10.2 Collection of Integrated Whole-Air Samples
10.2.1 Assemble the sampling apparatus as shown in Figure 2.
The connecting lines between the sample pump and the
canister(s) should be as short as possible to minimize
their volume. A second canister is used when a duplicate
sample is desired for quality assurance (QA) purposes
(see Section 12.2.4). The small auxiliary vacuum pump
purges the inlet manifold or lines with a flow of
several L/min to minimize the sample residence time.
The larger metal bellows pump takes a small portion of
this sample to fill and pressurize the sample canister(s).
Both pumps should be shock-mounted to minimize vibration.
Prior to field use, each sampling system should be leak
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tested. The outlet side of the metal bellows pump can
be checked for leaks by attaching the 0-30 psig pressure
gauge to the canister(s) inlet via connecting tubing and
pressurizing to 2 atmospheres or approximately 29.4 psig.
If pump and connecting lines are leak free pressure should
remain at +2 psig for 15 minutes. To check the inlet
side, plug the sample inlet and insure that there is no
flow at the outlet of the pump.
10.2.2 Calculate the flow rate needed so that the canister(s)
are pressurized to approximately one atmosphere above
ambient pressure (2 atmospheres absolute pressure)
over the desired sample period, utilizing the following
equation:
F = (P)(V)(N)
(T)(60)
where:
F = flow rate (cm^/min)
P = final canister pressure (atmospheres absolute)
= (Pg/Pa) + 1
V = volume of the canister (cm3)
N = number of canisters connected together for
simultaneous sample collection
T = sample period (hours)
Pg = gauge pressure in canister, psig (kPa)
Pa = standard atmospheric pressure, 14.7 psig (101 kPa)
For example, if one 6-L canister is to be filled to 2
atmospheres absolute pressure (14.7 psig) in 3 hours,
the flow rate would be calculated as follows:
F = 2 x 6000 x 1 = 67 cm3/min
3 x 60
10.2.3 Select a critical orifice or hypodermic needle suitable
to maintain a substantially constant flow at the cal-
culated flow rate into the canister(s) over the desired
sample period. A 30-gauge hypodermic needle, 2.5 cm
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long, provides a flow of approximately 65 cm3/min with
the Metal Bellows Model MBV-151 pump (see Figure 4).
Such a needle will maintain approximately constant flow
up to a canister pressure of about 10 psig (71 kPa),
after which the flow drops with increasing pressure.
At 14.7 psig (2 atmospheres absolute pressure), the
flow is about 10% below the original flow.
10.2.4 Assemble the 2.0 micron stainless steel in-line particu-
late filter and position it in front of the critical
orifice. A suggested filter-hypodermic needle assembly
can be fabricated as illustrated in Figure 4.
10.2.5 Check the sampling system for contamination by filling
two evacuated, cleaned canister(s) (See Section 10.1)
with humidified zero air through the sampling system.
Analyze the canisters according to Section 11.4. The
sampling system is free of contamination if the canisters
contain less than 0.02 ppmC hydrocarbons, similar to
that of humidified zero air.
10.2.6 During the system contamination check procedure, check
the critical orifice flow rate on the sampling system
to insure that sample flow rate remains relatively con-
stant (+10%) up to about 2 atmospheres absolute pressure
(101 kPa). Note: A drop in the flow rate may occur
near the end of the sampling period as the canister
pressure approaches two atmospheres.
10.2.7 Reassemble the sampling system. If the inlet sample line
is longer than 3 meters, install an auxiliary pump to
ventilate the sample line, as illustrated in Figure 2.
10.2.8 Verify that the timer, pump(s) and solenoid valve are
connected and operating properly.
10.2.9 Verify that the timer is correctly set for the desired
sample period, and that the solenoid valve is closed.
10.2.10 Connect a cleaned, evacuated canister(s) (Section 10.1)
to the non-contaminated sampling system, by way of the
solenoid valve, for sample collection.
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10.2.11 Make sure the solenoid valve is closed. Open the
canister valve(s). Temporarily connect a small rotameter
to the sample inlet to verify that there is no flow.
Note: Flow detection would indicate a leaking (or open)
solenoid valve. Remove the rotameter after leak de-
tection procedure.
10.2.12 Fill out the necessary information on the Field Data
Sheet (Figure 7).
10.2.13 Set the automatic timer to start and stop the pump
or pumps to open and close the solenoid valve at the
appropriate time for the intended sample period.
Sampling will begin at the pre-determined time.
10.2.14 After the sample period, close the canister valve(s) and
disconnect the canister(s) from the sampling system.
Connect a pressure gauge to the canister(s) and briefly
open and close the canister valve. Note the canister
pressure on the Field Data Sheet (see Figure 7). The
canister pressure should be approximately 2 atmospheres
absolute [1 atmosphere or 101 kPa (gauge)]. Note: If
the canister pressure is not approximately 2 atmospheres
absolute (14.7 psig), determine and correct the cause be-
fore next sample. Re-cap canister valve.
10.2.15 Fill out the identification tag on the sample canister(s)
and complete the Field Data Sheet as necessary. Note
any activities or special conditions in the area (rain,
smoke, etc.) that may affect the sample contents on the
sampling data sheet.
10.2.16 Return the canister(s) to the analytical system for
analysis.
11. Sample Analysis
11.1 Analytical System Leak Check
11.1.1 Before sample analysis, the analytical system is assembled
(see Figure 1) and leak checked.
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11.1.2 To leak check the analytical system, place the six-port
gas valve in the trapping position. Disconnect and cap
the absolute pressure gauge. Insert a pressure gauge
capable of recording up to 60 psig at the vacuum valve
outlet.
11.1.3 Attach a valve and a zero air supply to the sample
inlet port. Pressurize the system to about 50 psig
(350 kPa) and close the valve.
11.1.4 Wait approximately 3 hrs. and re-check pressure. If
the pressure did not vary more than +_ 2 psig, the '
system is considered leak tight.
11.1.5 If the system is leak free, de-pressurize and reconnect
absolute pressure gauge.
11.1.6 The analytical system leak check procedure needs to
be performed during the system checkout, during a series
of analysis or if leaks are suspected. This should be
part of the user-prepared SOP manual (see Section 12.1).
11.2 Sample Volume Determination
11.2.1 The vacuum reservoir and absolute pressure gauge are
used to meter a precisely repeatable volume of sample
air through the cryogenically-cooled trap, as follows:
With the sample valve closed and the vacuum valve open,
the reservoir is first evacuated with the vacuum pump
to a predetermined pressure (e.g., 100 mm Hg). Then
the vacuum valve is closed and the sample valve is
opened to allow sample air to be drawn through the
cryogenic trap and into the evacuated reservoir until
a second predetermined reservoir pressure is reached
(e.g., 300 mm Hg). The (fixed) volume of air thus
sampled is determined by the pressure rise in the
vacuum reservoir (difference between the predetermined
pressures) as measured by the absolute pressure gauge
(see Section 12.2.1).
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11.2.2 The sample volume can be calculated by:
V
s (P
where:
Vs = volume of air sampled (standard cm3)
AP = pressure difference measured by gauge (mm Hg)
O
Vp = volume of vacuum reservoir (cm0)
usually 1 L
Ps = standard pressure (760 mm Hg)
For example, with a vacuum reservoir of 1000 cm3 and a
pressure change of 200 mm Hg (100 to 300 mm Hg), the volume
sampled would be 263 cm3. [Note: Typical sample volume
using this procedure is between 200-300 cm3.]
11.2.3 The sample volume determination need only be performed once
during the system check-out and shall be part of the
user-prepared SOP Manual (see Section 12.1).
11.3 Analytical System Dynamic Calibration
11.3.1 Before sample analysis, a complete dynamic calibration
of the analytical system should be carried out at five or
more concentrations on each range to define the calibra-
tion curve. This should be carried out initially and
periodically thereafter [may be done only once during
a series of analyses]. This should be part of the
user-prepared SOP Manual (See Section 12.1). The
calibration should be verified with two or three-point
calibration checks (including zero) each day the analyt-
ical system is used to analyze samples.
11.3.2 Concentration standards of propane are used to calibrate
the analytical system. Propane calibration standards
may be obtained directly from low concentration cylinder
standards or by dilution of high concentration cylinder
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standards with zero air (see Section 8.3). Dilution
flow rates must be measured accurately, and the combined
gas stream must be mixed thoroughly for successful cali-
bration of the analyzer. Calibration standards should
be sampled directly from a vented manifold or tee. Note:
Remember that a propane NMOC concentration in ppmC is
three times the volumetric concentration in ppm.
11.3.3 Select one or more combinations of the following parameters
to provide the desired range or ranges (e.g., 0-1.0 ppmC
or 0-5.0 ppmC): FID attenuator setting, output voltage
setting, integrator resolution (if applicable), and sample
volume. Each individual range should be calibrated sep-
arately and should have a separate calibration curve.
Note: Modern GC integrators may provide automatic ranging
such that several decades of concentration may be covered
in a single range. The user-prepared SOP manual should
address variations applicable to a specific system design
(see Section 12.1).
11.3.4 Analyze each calibration standard three times according
to the procedure in Section 11.4. Insure that flow
rates, pressure gauge start and stop readings, initial
cryogen liquid level in the Dewar, timing, heating, inte-
grator settings, and other variables are the same as
those that will be used during analysis of ambient
samples. Typical flow rates for the gases are: hydrogen,
30 cm^/minute; helium carrier, 30 cm^/minute; burner
air, 400 cm3/minute.
11.3.5 Average the three analyses for each concentration standard
and plot the calibration curve(s) as average integrated peak
area reading versus concentration in ppmC. The relative
standard deviation for the three analyses should be less
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than 3% (except for zero concentration). Linearity should
be expected; points that appear to deviate abnormally
should be repeated. Response has been shown to be linear
over a wide range (0-10,000 ppbC). If nonlinearity is
observed, an effort should be made to identify and correct
the problem. If the problem cannot be corrected, addi-
tional points in the nonlinear region may be needed to
define the calibration curve adequately.
11.4 Analysis Procedure
11.4.1 Insure the analytical system has been assembled properly,
leaked checked, and properly calibrated through a dynamic
standard calibration. Light the FID detector and allow to
stabilize.
11.4.2 Check and adjust the helium carrier pressure to provide the
correct carrier flow rate for the system. Helium is used
to purge residual air and methane from the trap at the
end of the sampling phase and to carry the re-volatilized
NMOC from the trap into the FID. A single-stage auxiliary
regulator between the cylinder and the analyzer may not
be necessary, but is recommended to regulate the helium
pressure better than the multistage cylinder regulator.
When an auxiliary regulator is used, the secondary stage
of the two-stage regulator must be set at a pressure
higher than the pressure setting of the single-stage
regulator. Also check the FID hydrogen and burner air
flow rates (see 11.3.4).
11.4.3 Close the sample valve and open the vacuum valve to
evacuate the vacuum reservoir to a specific predetermined
value (e.g., 100 mm Hg).
11.4.4 With the trap at room temperature, place the six-port
valve in the inject position.
11.4.5 Open the sample valve and adjust the sample flow rate
needle valve for an appropriate trap flow of 50-100
cm3/min. Note: The flow will be lower later, when the
trap is cold.
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11.4.6 Check the sample canister pressure before attaching it
to the analytical system and record on Field Data
Sheet (see Figure 7). Connect the sample canister or
direct sample inlet to the six-port valve, as shown in
Figure 1. For a canister, either the canister valve
or an optional fine needle valve installed between the
canister and the vent is used to adjust the canister
flow rate to a value slightly higher than the trap
flow rate set by the sample flow rate needle valve.
The excess flow exhausts through the vent, which
assures that the sample air flowing through the trap
is at atmospheric pressure. The vent is connected to
a flow indicator such as a rotameter as an indication of
vent flow to assist in adjusting the flow control
valve. Open the canister valve and adjust the canister
valve or the sample flow needle valve to obtain a
moderate vent flow as indicated by the rotameter. The
sample flow rate will be lower (and hence the vent
flow rate will be higher) when the the trap is cold.
11.4.7 Close the sample valve and open the vacuum valve (if
not already open) to evacuate the vacuum reservoir.
With the six-port valve in the inject position and the
vacuum valve open, open the sample valve for 2-3 minutes
[with both valves open, the pressure reading won't
change] to flush and condition the inlet lines.
11.4.8 Close the sample valve and evacuate the reservoir to
the predetermined sample starting pressure (typically
100 mm Hg) as indicated by the absolute pressure gauge.
11.4.9 Switch the six-port valve to the sample position.
11.4.10 Submerge the trap in the cryogen. Allow a few minutes
for the trap to cool completely (indicated when the
cryogen stops boiling). Add cryogen to the initial
level used during system dynamic calibration. The level
of the cryogenic liquid should remain constant with
respect to the trap and should completely cover the
beaded portion of the trap.
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11.4.11 Open the sample valve and observe the increasing pressure
on the pressure gauge. When it reaches the specific pre-
determined pressure (typically 300 mm Hg) representative
of the desired sample volume (Section 11.2), close the
sample valve.
11.4.12 Add a little cryogen or elevate the Dewar to raise the
liquid level to a point slightly higher (3-15 mm) than
the initial level at the beginning of the trapping.
Note: This insures that organics do not bleed from the
trap and are counted as part of the NMOC peak(s).
11.4.13 Switch the 6-port valve to the inject position, keeping
the cryogenic liquid on the trap until the methane and
upset peaks have deminished (10-20 seconds). Now close
the canister valve to conserve the remaining sample in
the canister.
11.4.14 Start the integrator and remove the Dewar flask containing
the cryogenic liquid from the trap.
11.4.15 Close the GC oven door and allow the GC oven (or alter-
nate trap heating system) to heat the trap at a predeter-
mined rate (typically, 30°C/min) to 90°. Heating the trap
volatilizes the concentrated NMOC such that the FID pro-
duces integrated peaks. A uniform trap temperature rise
rate (above 0°C) helps to reduce variability and facili-
tates more accurate correction for the moisture-shifted
baseline. With a chromatograph oven to heat the trap,
the following parameters have been found to be acceptable:
initial temperature, 30°C; initial time, 0.20 minutes
(following start of the integrator); heat rate, 30°/minute;
final temperature, 90°C.
11.4.16 Use the same heating process and temperatures for both
calibration and sample analysis. Heating the trap too
quickly may cause an initial negative response that
could hamper accurate integration. Some initial exper-
imentation may be necessary to determine the optimal
heating procedure for each system. Once established,
the procedure should be consistent for each analysis
as outlined in the user-prepared SOP Manual.
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11.4.17 Continue the integration (generally, in the range of
1-2 minutes is adequate) only long enough to include
all of the organic compound peaks and to establish the
end point FID baseline, as illustrated in Figure 8.
The integrator should be capable of marking the begin-
ning and ending of peaks, constructing the appropriate
operational baseline between the start and end of the
integration period, and calculating the resulting
corrected peak area. This ability is necessary because
the moisture in the sample, which is also concentrated
in the trap, will cause a slight positive baseline
shift. This baseline shift starts as the trap warms
and continues until all of the moisture is swept from
the trap, at which time the baseline returns to its
normal level. The shift always continues longer than
the ambient organic peak(s). The integrator should be
programmed to correct for this shifted baseline by
ending the integration at a point after the last NMOC
peak and prior to the return of the shifted baseline to
normal (see Figure 8) so that the calculated operational
baseline effectively compensates for the water-shifted
baseline. Electronic integrators either do this auto-
matically or they should be programmed to make this cor-
rection. Alternatively, analyses of humidified zero air
prior to sample analyses should be performed to determine
the water envelope and the proper blank value for
correcting the ambient air concentration measurements
accordingly. Heating and flushing of the trap should
continue after the integration period has ended to
insure all water has been removed to prevent buildup of
water in the trap. Therefore, be sure that the 6-port
valve remains in the inject position until all moisture
has purged from the trap (3 minutes or longer).
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11.4.18 Use the dynamic calibration curve (see Section 11.3)
to convert the integrated peak area reading into
concentration units (ppmC). Note that the NMOC peak
shape may not be precisely reproducible due to vari-
ations in heating the trap, but the total NMOC peak
area should be reproducible.
11.4.19 Analyze each canister sample at least twice and report
the average NMOC concentration. Problems during an
analysis occasionally will cause erratic or incon-
sistent results. If the first two analyses do not
agree within +_ 5% relative standard deviation (RSD),
additional analyses should be made to identify in-
accurate measurements and produce a more accurate
average (see also Section 12.2.).
12. Performance Criteria and Quality Assurance
This section summarizes required quality assurance measures and pro-
vides guidance concerning performance criteria that should be achieved
within each laboratory.
12.1 Standard Operating Procedures (SOPs)
12.1.1 Users should generate SOPs describing and documenting
the following activities in their laboratory: (1)
assembly, calibration, leak check, and operation of the
specific sampling system and equipment used; (2) prepara-
tion, storage, shipment, and handling of samples; (3)
assembly, leak-check, calibration, and operation of the
analytical system, addressing the specific equipment used;
(4) canister storage and cleaning; and (5) all aspects of
of data recording and processing, including lists of
computer hardware and software used.
12.1.2 SOPs should provide specific stepwise instructions and
should be readily available to, and understood by, the
laboratory personnel conducting the work.
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12.2 Method Sensitivity, Accuracy, Precision and Linearity
12.2.1 The sensitivity and precision of the method is proportional
to the sample volume. However, ice formation in the
trap may reduce or stop the sample flow during trapping
if the sample volume exceeds 500 cm3. Sample volumes
below about 100-150 cm3 may cause increased measurement
variability due to dead volume in lines and valves. For
most typical ambient NMOC concentrations, sample volumes
in the range of 200-400 cm3 appear to be appropriate.
If a response peak obtained with a 400 cm3 sample is
off scale or exceeds the calibration range, a second
analysis can be carried out with a smaller volume. The
actual sample volume used need not be accurately known
if it is precisely repeatable during both calibration
and analysis. Similarly, the actual volume of the
vacuum reservoir need not be accurately known. But the
reservoir volume should be matched to the pressure
range and resolution of the absolute pressure gauge so
that the measurement of the pressure change in the reser-
voir, hence the sample volume, is repeatable within 1%.
A 1000 cm3 vacuum reservoir and a pressure change of
200 mm Hg, measured with the specified pressure gauge,
have provided a sampling precision of +_ 1.31 cm3. A
smaller volume reservoir may be used with a greater
pressure change to accommodate absolute pressure gauges
with lower resolution, and vice versa.
12.2.2 Some FID detector systems associated with laboratory
chromatographs may have autoranging. Others may
provide attenuator control and internal full-scale
output voltage selectors, an appropriate combination
should be chosen so that an adequate output level for
accurate integration is obtained down to the detection
limit; however, the electrometer or integrator must not
be driven into saturation at the upper end of the
calibration. Saturation of the electrometer may be
indicated by flattening of the calibration curve at
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high concentrations. Additional adjustments of range
and sensitivity can be provided by adjusting the sample
volume used, as discussed in Section 12.2.1.
12.2.3 System linearity has been documented (6) from 0 to 10,000
ppbC.
12.2.4 Some organic compounds contained in ambient air are
"sticky" and may require repeated analyses before they
fully appear in the FID output. Also, some adjustment
may have to be made in the integrator off time setting
to accommodate compounds that reach the FID late in the
analysis cycle. Similarly, "sticky" compounds from
ambient samples or from contaminated propane standards
may temporarily contaminate the analytical system and
can affect subsequent analyses. Such temporary contam-
ination can usually be removed by repeated analyses of
humidified zero air.
12.2.5 Simultaneous collection of duplicate samples decreases
the possibility of lost measurement data from samples
lost due to leakage or contamination in either of the
canisters. Two (or more) canisters can be filled simul-
taneously by connecting them in parallel (see Figure 2(a))
and selecting an appropriate flow rate to accommodate
the number of canisters (Section 10.2.2). Duplicate (or
replicate) samples also allow assessment of measurement
precision based on the differences between duplicate samples
(or the standard deviations among replicate samples).
13. Method Modification
13.1 Sample Metering System
13.1.1 Although the vacuum reservoir and absolute pressure gauge
technique for metering the sample volume during analysis is
efficient and convenient, other techniques should work also.
13.1.2 A constant sample flow could be established with a vacuum
pump and a critical orifice, with the six-port valve being
switched to the sample position for a measured time period.
-------
T012-28
A gas volume meter, such as a wet test meter, could
also be used to measure the total volume of sample air
drawn through the trap. These alternative techniques
should be tested and evaluated as part of a user-prepared
SOP manual.
13.2 FID Detector System
13.2.1 A variety of FID detector systems should be adaptable to
the method.
13.2.2 The specific flow rates and necessary modifications for
the helium carrier for any alternative FID instrument
should be evaluated prior to use as part of the user-
prepared SOP manual.
13.3 Range
13.3.1 It may be possible to increase the sensitivity of the
method by increasing the sample volume. However,
limitations may arise such as plugging of the trap by ice.
13.3.2 Any attempt to increase sensitivity should be evaluated
as part of the user-prepared SOP manual.
13.4 Sub-Atmospheric Pressure Canister Sampling
13.4.1 Collection and analysis of canister air samples at sub-
atmospheric pressure is also possible with minor modifi-
cations to the sampling and analytical procedures.
13.4.2 Method TO-14, "Integrated Canister Sampling for Selective
Organics: Pressurized and Sub-atmospheric Collection
Mechanism," addresses sub-atmospheric pressure canister
sampling. Additional information can be found in the
literature (11-17).
-------
T012-29
1. Uses, Limitations, and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors, EPA-
450/2-77-21a, U.S. Environmental Protection Agency, Research Triangle
Park, NC, November 1977.
2. Guidance for Collection of Ambient Non-Methane Organic Compound
TNMOC) Data for Use in 1982 Ozone SIP Development. EPA-450/4-80-011,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
June 1980.
3. H. B. Singh, Guidance for the Collection and Use of Ambient Hydrocarbons
Species Data in Development of Ozone Control Strategies, EPA-450/480-008.
U.S. Environmental Protection Agency, Research Triangle Park, NC,
April 1980.
4. R. M. Riggin, Technical Assistance Document for Sampling and Analysis
of Toxic Organic Compounds in Ambient Air, EPA-600/483-027, U.S.
Environmental Protection Agency, Research Triangle Park, NC, 1983.
5. M. J. Jackson, et^ _al_., Technical Assistance Document for Assembly and
Operation of the Suggested Preconcentration Direct Flame lonization
Detection (PDFID) Analytical System, publication scheduled for late
1987; currently available in draft form from the Qualilty Assurance
Division, MD-77, U.S. Environmental Protection Agency, Research
Triangle Park, NC 27711.
6. R. K. M. Jayanty, et^ aj_., Laboratory Evaluation of Non-Methane Organic
Carbon Determination in Ambient Air by Cryogenic Preconcentration and
Flame lonization Detection, EPA-600/54-82-019, U.S. Evironmental Protec-
tion Agency, Research Triangle Park, NC, July 1982.
7. R. D. Cox, jet^ ^1_., "Determination of Low Levels of Total Non-Methane
Hydrocarbon Content in Ambient Air", Environ. Sci. Techno!., JUS (1):57.
1982.
8. F. F. McElroy, et^ aj_., A Cryogenic Preconcentration - Direct FID (PDFID)
Method for Measurement of NMOC in the Ambient Air, EPA-600/4-85-063,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
August 1985.
9. F. W. Sexton, et^ jjl_., A Comparative Evaluation of Seven Automated
Ambient Non-Methane Organic Compound Analyzers, EPA-600/5482-046,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
August 1982.
10. H. G. Richter, Analysis of Organic Compound Data Gathered During 1980
in Northeast Corridor Cities, EPA-450/4-83-017, U.S. Environmental
Protection Agency, Research Triangle Park, NC, April 1983.
-------
T012-30
11. Cox, R. D. "Sample Collection and Analytical Techniques for Volatile
Organics in Air," presented at APCA Speciality Conference, Chicago, II
March 22-24, 1983.
12. Rasmussen, R. A. and Khalil, M.A.K. " Atmospheric Halocarbons:
Measurements and Analyses of Selected Trace Gases," Proc. NATO ASI on
Atmospheric Ozone, 1980, 209-231.
13. Oliver, K. D., Pleil J.D. and McClenny, W.A. "Sample Intergrity of
Trace Level Volatile Organic Compounds in Ambient Air Stored in
"SUMMA®" Polished Canisters," accepted for publication in Atmospheric
Environment as of January 1986. Draft available from W. A. McClenny,
MD-44, EMSL, EPA, Research Triangle Park, NC 27711.
14. McClenny, W. A. Pleil J.D. Holdren, J.W.; and Smith, R.N.; 1984.
" Automated Cryogenic Preconcentration and Gas Chromatographic
Determination of Volatile Organic Compounds," Anal. Chem. 56:2947.
15. Pleil, J. D. and Oliver, K. D., 1985, "Evaluation of Various Config-
urations of Nafion Dryers: Water Removal from Air Samples Prior to
Gas Chromatographic Analysis". EPA Contract No. 68-02-4035.
16. Oliver, K. D.; Pleil, and McClenny, W. A.; 1986. "Sample Integrity
of Trace Level Volatile Organic Compounds in Ambient Air Stored in
Summa® Polished Canisters," Atmospheric Environ. 20:1403.
17. Oliver, K. D. Pleil, J. D., 1985, "Automated Cryogenic Sampling and
Gas Chromatographic Analysis of Ambient Vapor-Phase Organic Compounds:
Procedures and Comparison Tests," EPA Contract No. 68-02-4035,
Research Triangle Park, NC, Northrop Services, Inc. - Environmental
Sciences.
-------
T012-31
PRESSURE
REGULATOR
ABSOLUTE
PRESSURE GAUGE
VACUUM
VALVE
VACUUM
PUMP
SAMPLE
VALVE
VACUUM
RESERVOIR
FINE
NEEDLE
VALVE
(SAMPLE FLOW
ADJUSTMENT)
He
GAS
PURIFIER
VENT
PRESSURIZED (EXCESS)
CANISTER
SAMPLE
CANISTER
VALVE
CANSITER
DIRECT AIR SAMPLING
DEWAR
FLASK
GLASS
BEADS
ROTAMETER
CRYOGENIC
TRAP COOLER
(LIQUID ARGON)
PRESSURE
GAS REGULATOR
PURIFIER
(OPTIONAL FINE
NEEDLE VALVE)
INTEGRATOR
RECORDER
FIGURE 1. SCHEMATIC OF ANALYTICAL SYSTEM FOR
NMOC-TWO SAMPLING MODES
-------
T012-32
SAMPLE
IN
CRITICAL
ORIFICE
AUXILIARY IN
VACUUM
PUMP
TIMER
SOLENOID
VALVE
METAL
BELLOWS
PUMP
PRESSURE
GAUGE
CANISTER(S)
FIGURE 2. SAMPLE SYSTEM FOR AUTOMATIC COLLECTION
OF 3-HOUR INTEGRATED AIR SAMPLES
-------
T012-33
TIMER
SWITCH
100K
RED
115 VAC
40^fd, 450 V DC
R2 100K
BLACK
PUMP'1
4LVfd, 450 V DC o2
WHITE
COMPONENTS
Capacitor Ci and C2 - 40 u(, 450 VDC (Sprague Atom* TVA 1712 or equivalent)
Resister RI and Rj - 0.5 watt. 5% tolerance
Diode DI and 02 • 1000 PRV, 2.5 A (RCA. SK 3081 or equivalent)
MAGNELATCH
SOLENOID
VALVE
FIGURE 3[a]. SIMPLE CIRCUIT FOR OPERATING MAGNELATCH VALVE
TIMER
SWITCH
O
115 VAC
COMPONENTS
Bridge Rectifier - 200 PRV, 1.5 A (RCA. SK 3105 or equivalent)
Oiode D-i and 02 - 1000 PRV. 2.5 A (RCA, SK 3081 or equivalent)
Capacitor Ci - 200 ul, 250 VDC (Sprague Atom* TVA 1528 or equivalent)
Capacitor Cz - 20 uf, 400 VOC Non-Polarized (Sprague Atom* TVAN 1652 or equivalent)
Relay - 10,000 ohm coil, 3.5 ma (AMF Potter and Brumfield, KCP 5, or equivalent)
Resister RI and KZ • 0-5 watt. 5% tolerance
MAGNELATCH
SOLENOID
VALVE
20 uf
400 Voll
NON-POLARIZED
FIGURE 3[b], IMPROVED CIRCUIT DESIGNED TO HANDLE POWER INTERRUPTIONS
FIGURE 3. ELECTRICAL PULSE CIRCUITS FOR DRIVING
SKINNER MAGNELATCH SOLENOID VALVE
WITH A MECHANICAL TIMER
-------
T012-34
'F' SERIES COMPACT, INLINE FILTER
W/2 urn SS SINTERED ELEMENT
FEMALE CONNECTOR, 0.25 in O.D. TUBE TO
0.25 in FEMALE NPT
HEX NIPPLE, 0.25 in MALE NPT BOTH ENDS
30 GAUGE x 1.0 in LONG HYPODERMIC
NEEDLE (ORIFICE)
FEMALE CONNECTOR, 0.25 in O.D. TUBE TO
0.25 in FEMALE NPT
THERMOGREEN LBI 6 mm (0.25 in)
SEPTUM (LOW BLEED)
0.25 in PORT CONNECTOR W/TWO 0.25 in NUTS
FIGURE 4. FILTER AND HYPODERMIC NEEDLE
ASSEMBLY FOR SAMPLE INLET FLOW
CONTROL
-------
T012-35
3-PORT
ZERO AIR
SUPPLY
V
GAS
VALVE
-KM O
l^\| V,.
VENT VALVE /
CHECK VALVE
^
^
T
u
s
CRYOGENIC
'TRAP
VACUUM VACUUM PUMP
PUMP SHUT OFF VALVE VENT VALVE
ZERO AIR
SUPPLY
VENT SHUT OFF
VALVE
VACUUM SHUT OFF
VALVE
VENT
VENT SHUT OFF
VALVE
HUMIDIFIER
CRYOGENIC
TRAP
VACUUM GAUGE
SHUT OFF VALVE
— PRESSURE
GAUGE
ZERO SHUT OFF
VALVE
FLOW
CONTROL
VALVE
VENT SHUT OFF
VALVE
A
MANIFOLD
J_]H CANISTER VALVE
SAMPLE CANISTERS
FIGURE 5. CANISTER CLEANING SYSTEM
-------
T012-36
TUBE LENGTH: -30 cm
O.D.: 0.32 cm
I.D.: 021 cm
CRYOGENIC LIQUID LEVEL'
60/80 MESH GLASS BEADS
-GLASS WOOL-
~13 cm
(TO FIT DEWAR)
FIGURE 6. CRYOGENIC SAMPLE TRAP DIMENSIONS
-------
GENERAL INFORMATION:
PRESSURIZED CANISTER SAMPLING DATA SHEET
PROJECT:
SITE:
LOCATION:
MONITOR STATION NUMBER:
PUMP SERIAL NUMBER:
OPERATOR:
ORIFICE IDENTIFICATION:
FLOW RATE:
CALIBRATED BY:
LEAK CHECK
Pass
Fail
FIELD DATA:
Date
Canister
Serial
Number
Sample
Number
Sample Time
Start
Stop
Average Atmospheric Conditions
Temperature
Pressure
Relative Humidity
Canister pressure
Final , Laboratory
Comments
o
I—»
ro
CO
Date
Title
Signature
FIGURE 7. EXAMPLE SAMPLING DATA SHEET
-------
T012-38
NMOC
PEAK
w
w
O
D-
(0
W
DC
START
INTEGRATION
END
INTEGRATION
CONTINUED HEATING
OF TRAP
WATER-SHIFTED
BASELINE
1
t
OPERATIONAL BASELINE
CONSTRUCTED BY INTEGRATOR
TO DETERMINE CORRECTED AREA
NORMAL BASELINE
TIME (MINUTES)
FIGURE 8. CONSTRUCTION OF OPERATIONAL BASELINE
AND CORRESPONDING CORRECTION OF
PEAK AREA
-------
Revision 1.0
June, 1988
METHOD TO-13
THE DETERMINATION OF BENZO(a)PYRENE [B(a)P] AND OTHER
POLYNUCLEAR AROMATIC HYDROCARBONS (PAH's) IN AMBIENT AIR USING GAS
CHROMATOGRAPHIC (GC) AND HIGH PERFORMANCE LIQUID
CHROMATOGRAPHIC (HPLC) ANALYSIS
OUTLINE
I. Scope
2. Applicable Documents
3. Summary of Method
4* Significance
5. Definitions
6. Interferences
7. Safety
8. Apparatus
8.1 Sample Collection
8.2 Sample Clean-up and Concentration
8.3 Sample Analysis
8.3.1 Gas Chromatography with Flame lonization Detection
8.3.2 Gas Chromatography with Mass Spectroscopy Detection
Coupled with Data Processing System (GC/MS/DS)
8.3.3 High Performance Liquid Chromatography System
9. Reagents and Materials
9.1 Sample Collection
9.2 Sample Clean-up and Concentration
9.2.1 Soxhlet Extraction
9.2.2 Solvent Exchange
9.2.3 Column Clean-up
9.3 Sample Analysis
9.3.1 Gas Chromatography Detection
9.3.2 High Performance Liquid Chromatography Detection
10. Preparation of Sampling Filter and Adsorbent
10.1 Sampling Head Configuration
10.2 Glass Fiber Filter Preparation
10.3 XAD-2 Adsorbent Preparation
10.4 PUF Sampling Cartridge Preparation
11. Sample Collection
11.1 Description of Sampling Apparatus
11.2 Calibration of Sampling System
11.2.1 Calibration of Flow Rate Transfer Standard
11.2.2 Initial Multi-point Calibration of High Volume Sampling System
Utilizing Flow Rate Transfer Standard
11.2.3 Single Point Audit of the High Volume Sampling System
Utilizing Flow Rate Transfer Standard
11.3 Sample Collection
12. Sample Clean-up and Concentration
12.1 Sample Identification
12.2 Soxhlet Extraction and Concentration
12.3 Solvent Exchange
12.4 Sample Clean-up by Solid Phase Exchange and Concentration
12.4.1 Method 610 Clean-up Procedure
12.4.2 Lobar Prepacked Column Procedure
-------
OUTLINE (cont'd)
13. Gas Chromatography (GC) with Flame lonization (FI) Detection
13.1 Analytical Technique
13.2 Analytical Sensitivity
13.3 Analytical Assembly
13.4 GC Calibration
13.4.1 External Standard Calibration Procedure
13.4.2 Internal Standard Calibration Procedure
13.5 Retention Time Window Determination
13.6 Sample Analysis
13.6.1 Sample Injection
13.6.2 Area Counts and Peak Height
13.6.3 Analyte Identification
13.6.4 Analyte Quantification
14. Gas Chromatography (GC) with Mass Spectroscopy (MS) Detection
14.2 Analytical System
14.2 Operation Parameters
14.3 Calibration Techniques
14.3.1 External Standard Calibration
14.3.2 Internal Standard Calibration
14.4 Sample Analysis
14.4.1 Preliminary Screening by GC/FID
14.4.2 Sample Injection
14.4.3 Area Counts
14.4.4 Analyte Identification
14.4.5 Spectrum Comparison
14.4.6 Analyte Quantification
14.5 GC/MS Performance Tests
14.5.1 Daily DFTPP Tuning
14.5.2 Daily 1-point Initial Calibration Check
14.5.3 12-hour Calibration Verification
15. High Performance Lliquid Chromatography (HPLC) Detection
15.1 Introduction
15.2 Solvent Exchange to Acetonitrile
15.3 HPLC Assembly
15.4 HPLC Calibration
15.4.1 Stock Standard Solution
15.4.2 Storage of Stock Standard Solution
15.4.3 Replacement of Stock Standard Solution
15.4.4 Calibration Standards
15.4.5 Analysis of Calibration Standards
15.4.6 Lingar Response
15.4.7 Daily Calibration
15.5 Sample Analysis
15.6 HPLC System Performance
15.7 HPLC Method Modification
16. Quality Assurance/Quality Control (QA/QC)
16.1 General System QA/QC
16.2 Process, Field and Solvent Blanks
16.3 Gas Chromatography with Flame lonization Detection
16.4 Gas Chromatography with Mass Spectroscopy Detection
16.5 High Performance Liquid Chromatography Detection
-------
OUTLINE (cont'd)
17. Calculations
17.1 Sample Volume
17.2 Sample Concentration
17.2.1 Gas Chromatography with Flame lonization Detection
17.2.2 Gas Chromatography with Mass Spectroscopy Detection
17.2.3 High Performance Liquid Chromatography Detection
17.3 Sample Conversion from ng/m3 to ppbv
18. Bibliography
-------
-------
METHOD TO-13
THE DETERMINATION OF BENZO(a)PYRENE [B(a)P] AND OTHER
POLYNUCLEAR AROMATIC HYDROCARBONS (PAHs) IN AMBIENT AIR USING GAS
CHROMATOGRAPHIC (GC) AND HIGH PERFORMANCE LIQUID
CHROMATOGRAPHIC (HPLC) ANALYSIS
1. Scope
1.1 Polynuclear aromatic hydrocarbons (PAHs) have received increased
attention in recent years in air pollution studies because some
of these compounds are highly carcinogenic or mutagenic. In par-
ticular, benzo[a]pyrene (B[a]P) has been identified as being
highly carcinogenic. To understand the extent of human exposure
to B[a]Ps and other PAHs, a reliable sampling and analytical method
has been established. This document describes a sampling and
analysis procedure for B[a]P and other PAHs involving a combination
quartz filter/adsorbent cartridge with subsequent analysis by gas
chromatography (GC) with flame ionization (FI) and mass spectrometry
(MS) detection (GC/FI and 6C/MS) or high resolution liquid chroma-
tography (HPLC). The analytical methods are a modification of EPA
Test Method 610 and 625, Methods for Organic Chemical Analysis of
Municipal and Industrial Wastewater, and Methods 8000, 8270, and
8310, Test Methods for Evaluation of Solid Waste.
1.2 Fluorescence methods were among the very first methods used for
detection of B[a]P and other PAHs as a carcinogenic constituent
of coal tar (1-7). Fluorescent methods are capable of measuring
subnanogram quantities of PAHs, but tend to be fairly non-selective.
The normal spectra obtained tended to be intense and lacked reso-
lution. Efforts to overcome this difficulty led to the use of
ultraviolet (UV) absorption spectroscopy as the detection method
coupled with pre-speci ated techniques involving liquid chromatog-
raphy (LC) and thin layer chromatography (TLC) to isolate specific
PAHs, particularly B[a]P (8). As with fluorescence spectroscopy, the
individual spectra for various PAHs are unique, although portions
of spectra for different compounds may be the same. As with flu-
oresence techniques, the possibility of spectra overlap required
complete separation of sample components to insure accurate measure-
ment of component levels. Hence, the use of UV absorption coupled
-------
T013-2
with pre-speciation involving LC and TLC and fluorescence spectro-
scopy has declined and is now being replaced with the more sensitive
high performance liquid chromatography (9) with UV/fluorescence detec-
tion and highly sensitive and specific gas chromatograph with either
flame ionization detector or coupled with mass spectroscopy (10-11).
1.3' The choice of GC and HPLC as the recommended procedures for analysis
of B[a]P and other PAHs are influenced by their sensitivity and
selectivity, along with their ability to analyze complex samples.
This method provides for both GC and HPLC approaches to the deter-
mination of B[a]P and other PAHs in the extracted sample.
1.4 The analytical methodology is well defined, but the sampling pro-
cedures can reduce the validity of the analytical results. Recent
studies (12-15) have indicated that non-volatile PAHs (vapor pres-
sure <10'8 mm Hg) may be trapped on the filter, but post-collection
volatilization problems may distribute the PAHs down stream of the
the filter to the back-up adsorbent. A wide variety of adsorbents
such as Tenax GC, XAD-2 resin and polyurethane foam (PUF) have been
used to sample B[a]P and other PAH vapors. All adsorbents have
demonstrated high collection efficiency for B[a]P in particular.
In general, XAD-2 resin has a higher collection efficiency (16-17)
for volatile PAHs than PUF, as well as a higher retention efficiency.
However, PUF cartridges are easier to handle in the field and main-
tain better flow characteristics during sampling. Likewise, PUF
has demonstrated its capability in sampling organochlorine pesticides
and polychlorinated biphenyls (Compendium Methods T04 and TO 10 re-
spectively), and polychlorinated dibenzo-p-dioxins (Compendium
Method T09). However, PUF has demonstrated a lower recovery effi-
ciency and storage capability for naphthalene and B[a]P, respectively,
than XAD-2. There have been no significant losses of PAHs, up to
30 days of storage at 0°C, using XAD-2. It also appears that XAD-2
resin has a higher collection efficiency for volatile PAHs than
PUF, as well as a higher retention efficiency for both volatile and
reactive PAHs. Consequently, while the literature cites weaknesses
and strengths of using either XAD-2 or PUF, this method covers both
the utilization of XAD-2 and PUF as the adsorbent to address post-
collection volatilization problems associated with B[a]P and other
reactive PAHs.
-------
T013-3
1.5 This method covers the determination of B[a]P specificially by
both GC and HPLC and enables the qualitative and quantitative
analysis of the other PAHs. They are:
Acenaphthene Benzo(k)fluoranthene
Acenaphthylene Chrysene
Anthracene Dibenzo(a,h)anthracene
Benzo(a)anthracene Fluoranthene
Benzo(a)pyrene Fluorene
Benzo(b)fluoranthene Indeno(l,2,3-cd)pyrene
Benzo(e)pyrene Naphthalene
Benzo(g,h,i)perylene Phenanthrene
Pyrene
The GC and HPLC methods are applicable to the determination of
PAHs compounds involving two-member rings or higher. Nitro-
PAHs have not been fully evaluated using this procedure; therefore,
they are not included in this method. When either of the methods
are used to analyze unfamiliar samples for any or all of the com-
pounds listed above, compound identification should be supported
by both techniques.
1.6 With careful attention to reagent purity and optimized analytical
conditions, the detection limits for GC and HPLC methods range from
1 ng to 10 pg which represents detection of B[a]P and other PAHs
in filtered air at levels below 100 pg/m3. To obtain this detection
limit, at least 100 m3 of air must be sampled.
2. Applicable Documents
2.1 ASTM Standards
2.1.1 Method D1356 - Definitions of Terms Relating to Atmospheric
Sampling and Analysis.
2.1.2 Method E260 - Recommended Practice for General Gas
Chromatography Procedures.
2.1.3 Method E355 - Practice for Gas Chromatography Terms and
Relationships.
2.1.4 Method E682 - Practice for Liquid Chromatography Terms and
Relationships.
2.1.5 Method D-1605-60 - Standard Recommended Practices for Sampling
Atmospheres for Analysis of Gases and Vapors.
2.2 Other Documents
2.2.1 Existing Procedures (18-25)
2.2.2 Ambient Air Studies (26-28)
-------
T013-4
2.2.3 U.S. EPA Technical Assistance Document (29-32)
2'2*4 General Metal Works Operating Procedures for Model PS-1
Sampler, General Metal Works, Inc., Village of Cleves, Ohio.
3. Summary of Method
3.1 Filters and adsorbent cartridges (containing XAD-2 or PUF) are
cleaned in solvents and vacuum-dried. The filters and adsorbent
cartridges are stored in screw-capped jars wrapped in aluminum
foil (or otherwise protected from light) before careful installa-
tion on a modified high volume sampler.
3.2 Approximately 325 m3 of ambient air is drawn through the filter
and adsorbent cartridge using a calibrated General Metal Works
Model PS-1 Sampler, or equivalent (breakthrough has not shown
to be a problem with sampling volumes of 325 m3).
3.3 The amount of air sampled through the filter and adsorbent car-
tridge is recorded, and the filter and cartridge are placed in
an appropriately labeled container and shipped along with blank
filter and adsorbent cartridges to the analytical laboratory
for analysis.
3.4 The filters and adsorbent cartridge are extracted by Soxhlet
extraction with appropriate solvent. The extract is concentrated
by Kuderna-Danish (K-D) evaporator, followed by silica gel clean-up
using column chromatography to remove potential interferences prior
to analysis.
3.5 The eluent is further concentrated by K-D evaporator, then analyzed
by either gas chromatograhy equipped with FI or MS detection or high
performance liquid chromatography (HPLC). The analytical system is
verified to be operating properly and calibrated with five concen-
tration calibration solutions, each analyzed in triplicate.
3.6 A preliminary analysis of the sample extract is performed to check
the system performance and to ensure that the samples are within
the calibration range of the instrument. If necessary, recalibrate
the instrument, adjust the amount of the sample injected, adjust
the calibration solution concentration, and adjust the data proces-
sing system to reflect observed retention times, etc.
3.7 The samples and the blanks are analyzed and used (along with the
amount of air sampled) to calculated the concentratuon of B[a]P in
ambient air.
-------
T013-5
3.8 Other PAHs can be determined both qualitatively and quantitatively
through optimization of the GC or HPLC procedures.
4. Significance
4.1 Several documents have been published which describe sampling and
analytical approaches for benzo[a]pyrene and other PAHs,-as out-
lined in Section 2.2. The attractive features of these methods
have been combined in this procedure. This method has been
validated in the laboratory; however, one must use caution when
employing it for specific applications.
4.2 The relatively low level of B[a]P and other PAHs in the environ- ,
ment requires use of high volume (^.7 cfm) sampling techniques
to acquire sufficient sample for analysis. However, the volatility
of certain PAHs prevents efficient collection on filter media
alone. Consequently, this method utilizes both a filter and a
backup adsorbent cartridge which provide for efficient collection
of most PAHs.
5. Definitions
Definitions used in this document and in any user-prepared standard
operating procedures (SOPs) should be consistent with ASTM Methods D1356,
D1605-60, E260, and E255. All abbreviations and symbols are defined with-
in this document at point of use.
5.1 Sampling efficiency (SE) - ability of the sampling medium to trap
vapors of interest. %SE is the percentage of the analyte of in-
terest colleted and retained by the sampling medium when it is
introduced as a vapor in air or nitrogen into the air sampler and
the sampler is operated under normal conditions for a period of
time equal to or greater than that required for the intended use.
5.2 Retention time (RT) - time to elute a specific chemical from a
chromatographic column. For a specific carrier gas flow rate,
RT is measured from the time the chemical is injected into the
gas stream until it appears at the detector.
5.3 High Performance Liquid Chromatography - an analytical method
based on separation of compounds of a liquid mixture through a
liquid chromatographic column and measuring the separated com-
ponents with a suitable detector.
-------
T013-6
5.4 Gradient elution - defined as increasing the strength of the
mobile phase during a chromatographic analysis. The net effect
of gradient elution is to shorten the retention time of compounds
strongly retained on the analytical column. Gradient elution may
be stepwise on continuous.
5.5 Method detection limit (MDL) - the minimum concentration of a sub-
stance that can be measured and reported with confidence and that
the value is above zero.
5.6 Kuderna-Danish apparatus - the Kuderna-Danish (KD) appartus is a
system for concentrating materials dissolved in volatile solvents.
5.7 Reverse phase liquid chromatography - reverse phase liquid chro-
matography involves a non-polar absorbent (C-18.0DS) coupled with
a polar solvent to separate non-polar compounds.
5.8 Guard column - guard columns in HPLC are usually short ( 5cm)
columns attached after the injection port and before the analytial
column to prevent particles and strongly retained compounds from
accumulating on the analytical column. The guard column should
always be the same stationary phase as the analytical column and
is used to extend the life of the analytical column.
5.9 MS-SIM - the GC is coupled to a select ion mode (SIM) detector
where the instrument is programmed to acquire data for only the
target compounds and to disregard all others. This is performed
using SIM coupled to retention time discriminators. The SIM
analysis procedure provides quantitative results.
5.10 Sublimation - Sublimation is the direct passage of a substance
from the solid state to the gaseous state and back into the solid
form without at any time appearing in the liquid state. Also
applied to the conversion of solid to vapor without the later
return to solid state, and to a conversion directly from the
vapor phase to the solid state.
5.11 Surrogate standard - A surrogate standard is a chemically inert
compound (not expected to occur in the environmental sample)
which is added to each sample, blank and matrix spiked sample
before extraction and analysis. The recovery of the surrogate
standard is used to monitor unusual matrix effects, gross sample
processing errors, etc. Surrogate recovery is evaluated for
acceptance by determining whether the measured concentration
falls within acceptable limits.
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5.12 Retention time window - Retention time window is determined for
each analyte of interest and is the time from injection to elution
of a specific chemical from a chromatographic column. The window
is determined by three injections of a single component standard over
a 72-hr period as plus or minus three times the standard deviation
of the absolute retention time for that analyte.
6. Interferences
6.1 Method interferences may be caused by contaminants in solvents,
reagents, glassware, and other sample processing hardware that
result in discrete artifacts and/or elevated baselines in the
detector profiles. All of these materials must be routinely
demonstrated to be free from interferences under the conditions
of the analysis by running laboratory reagent blanks.
6.1.1 Glassware must be scrupulously cleaned (33). Clean all
glassware as soon as possible after use by rinsing with
the last solvent used in it. This should be followed by
detergent washing with hot water, and rinsing with tap
water and reagent water. It should then be drained dry,
solvent rinsed with acetone and spectrographic grade
hexane. After drying and rinsing, glassware should be
sealed and stored in a clean environment to prevent any
accumulation of dust or other contaminants. Glassware
should be stored inverted or capped with aluminum foil.
6.1.2 The use of high purity water, reagents and solvents helps to
minimize interference problems. Purification of solvents
by distillation in all-glass systems may be required.
6.1.3 Matrix interferences may be caused by contaminants that
are coextracted from the sample. Additional clean-up by
column chromatography may be required (see Section 12.4).
6.2 The extent of interferences that may be encountered using liquid
chromatographic techniques has not been fully assessed. Although
GC and HPLC conditions described allow for unique resolution
of the specific PAH compounds covered by this method, other PAH
compounds may interfere. The use of column chromatography for
sample clean-up prior to GC or HPLC analysis will eliminate most
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of these interferences. The analytical system must, however, be
routinely demonstrated to be free of internal contaminants such
as contaminated solvents, glassware, or other reagents which may
lead to method interferences. A laboratory reagent blank is run
for each batch of reagents used to determine if reagents are
contaminant-free.
6.3 Although HPLC separations have been improved by recent advances
in column technology and instrumentation, problems may occur with
baseline noise, baseline drift, peak resolution and changes in
sensitivity. Problems affecting overall system performance can
arise (34). The user is encouraged to develop a standard operating
procedure (SOP) manual specific for his laboratory to minimize
problems affecting overall system performance.
6.4 Concern during sample transport and analysis is mentioned. Heat,
ozone, N02 and ultraviolet (UV) light may cause sample degradation.
These problems should be addressed as part of the user prepared
standard operating procedure manual. Where possible, incandescent
or UV-shield fluorescent lighting should be used during analysis.
7. Safety
7.1 The toxicity or carcinogenicity of each reagent used in this
method has not been precisely defined; however, each chemical
compound should be treated as a potential health hazard. From
this viewpoint, exposure to these chemicals must be reduced to
the lowest possible level by whatever means available. The
laboratory is responsible for maintaining a current awareness
file of Occupational Safety and Health Administration (OSHA)
regulations regarding the safe handling of the chemicals speci-
fied in this method. A reference file of material data handling
sheets should also be made available to all personnel involved in
the chemical analysis. Additional references to laboratory
safety are available and have been identified for the analyst
(35-37).
7.2 Benzo[a]pyrene has been tentatively classified as a known or
suspected, human or mammalian carcinogen. Many of the other PAHs
have been classified as carcinogens. Care must be exercised when
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working with these substances. This method does not purport to
address all of the safety problems associated with its use. It
is the responsibility of whoever uses this method to consult and
establish appropriate safety and health practices and determine
the applicability of regulatory limitations prior to use. The
user should be thoroughly familiar with the chemical and physical
properties of targeted substances (Table 1.0 and Figure 1.0).
7.3 Treat all selective polynuclear aromatic hydrocarbons as carcinogens.
Neat compounds should be weighed in a glove box. Spent samples and
unused standards are toxic waste and should be disposed according to
regulations. Regularly check counter tops and equipment with "black
light" for fluorescence as an indicator of contamination.
7.4 Because the sampling configuration (filter and backup adsorbent) has
demonstrated greater than 95% collection efficiency for targeted PAHs,
no field recovery evaluation will occur as part of this procedure.
8. Apparatus
8.1 Sample Collection
8.1.1 General Metal Works (GMW) Model PS-1 Sampler, or equi-
valent [General Metal Works, Inc., 145 South Miami Ave.,
Village of Cleves, Ohio, 45002, (800-543-7412)].
8.1.2 At least two Model PS-1 sample cartridges and filters
assembled for PS-1 sampler.
8.1.3 GMW Model PS-1 calibrator and associated equipment -
General Metal Works, Inc., Model GMW-40, 145 South Miami
Ave., Village of Cleves, Ohio, 45002, (800-543-7412).
8.1.4 Ice chest - to store samples at 0°C after collection.
8.1.5 Data sheets for each sample for recording the location and
sample time, duration of sample, starting time, and volume
of air sampled.
8.1.6 Airtight, labeled screw-capped container sample cartridges
(wide mouth, preferrably glass with Teflon seal or other non-
contaminating seals) to hold filter and adsorbent cartridge
during transport to analytical laboratory.
8.1.7 Portable Tripod Sampler (optional) - user prepared (38).
8.2 Sample Clean-up and Concentration
8.2.1 Soxhlet extractors capable of extracting GMW Model PS-1
filter and adsorbent cartridges (2.3" x 5" length), 500 ml
flask, and condenser.
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8.2.2 Pyrex glass tube furnace system for activating silica gel
at 180°C under purified nitrogen gas purge for an hour,
with capability of raising temperature gradually.
8.2.3 Glass vial, 40 ml.
8.2.4 Erlenmeyer flask, 50 ml - best source. [Note: Reuse of
glassware should be minimized to avoid the risk of cross-
contamination. All glassware that is used, especially glass-
ware that is reused, must be scrupulously cleaned as soon
as possible after use. Rinse glassware with the last solvent
used in it and then with high-purity acetone and hexane.
Wash with hot water containing detergent. Rinse with copious
amount of tap water and several portions of distilled water.
Drain, dry, and heat a muffle furnace at 400°C for 2 to 4
hours. Volumetric glassware must not be heated in a muffle
furnace; rather, it should be rinsed with high-purity acetone
and hexane. After the glassware is dry and cool, rinse it
with hexane, and store it inverted or capped with solvent-
rinsed aluminum foil in a clean environment.]
8.2.5 Polyester gloves for handling cartridges and filters.
8.2.6 Minivials - 2 ml, borosilicate glass, with conical reservoir
and screw caps lines with Teflon-faced silicone disks, and
a vial holder.
8.2.7 Stainless steel Teflon® coated spatulas and spoons.
8.2.8 Kuderna-Danish (KD) apparatus - 500 ml evaporation flask
(Kontes K-570001-500 or equivalent), 10 ml graduated con-
centrator tubes (Knotes K-570050-1025 or equivalent) with
ground-glass stoppers, and 3-ball macro Snyder Column (Kontes
K-5700010500, K-50300-0121, and K-569001-219, or equivalent).
8.2.9 Adsorption columns for column chromatography - 1-cm x 10-cm
with stands.
8.2.10 Glove box for working with extremely toxic standards and
reagents with explosion-proof hood for venting fumes from
solvents, reagents, etc.
8.2.11 Vacuum Oven - Vacuum drying oven system capable of maintaining
a vacuum at 240 torr (flushed with nitrogen) overnight.
8.2.12 Concentrator tubes and a nitrogen evaporation apparatus
with variable flow rate - best source.
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8.2.13 Laboratory refrigerator with chambers operating at 0°C and 4°C.
8.2.14 Boiling chips - solvent extracted, 10/40 mesh silicon car-
bide or equivalent.
8.2.15 Water bath - heated, with concentric ring cover, capable
of temperature control (+_ 5°C).
8.2.16 Vortex evaporator (optional).
8.3 Sample Analysis
8.3.1 Gas Chromatography with Flame lonization Detection (FID).
8.3.1.1 Gas Chromatography: Analytical system complete
with gas Chromatography suitable for on-column
injections and all required accessories, including
detectors, column supplies, recorder, gases, and
syringes. A data system for measuring peak areas
and/or peak heights is recommended.
8.3.1.2 Packed Column: 1.8-m x 2-mm I.D. glass column
packed with 3% OV-17 on Chromosorb W-AW-DMCS
(100/120 mesh) or equivalent (Supelco Inc.,
Supelco Park, Bellefonte, Pa. Supelco SPB-5).
8.3.1.3 Capillary Column: 30-m x 0.25-mm ID fused silica
column coated with 0.25 u thickness 5% phenyl,
90% methyl siloxane (Supelco Inc., Supelco Park,
Bellefonte, Pa.).
8.3.1.4 Detector: Flame lonization (FI)
8.3.2 Gas Chromatograph with Mass Spectroscopy Detection Coupled
with Data Processing System (GC/MS/DS).
8.3.2.1 The GC must be equipped for temperature programming,
and all required accessories must be available, in-
cluding syringes, gases, and a capillary column. The
GC injection port must be designed for capillary
columns. The use of splitless injection techniques
is recommended. On-column injection techniques can be
used but they may severely reduce column lifetime for
nonchemically bonded columns. In this protocol, a 1-3
uL injection volume is used consistently. With some
GC injection ports, however, 1 uL injections may pro-
duce some improvement in precision and chromatographic
-------
T013-12
separation. A 1 uL injection volume may be used if
adequate sensitivity and precision can be achieved.
[NOTE: If 1 uL is used as the injection volume, the
injection volumes for all extracts, blanks, calibra-
tion solutions and performance check samples must be
1 uL.]
8.3.2.2 Gas Chromatograph-Mass Spectrometer Interface. The
gas chromatograph is usually coupled directly to the
mass spectrometer source. The interface may include
a diverter valve for shunting the column effluent and
isolating the mass spectrometer source. All compo-
nents of the interface should be glass or glass-lined
stainless steel. The interface components should
be compatible with 320°C temperatures. Cold spots
and/or active surfaces (adsorption sites) in the
GC/MS interface can cause peak tailing and peak
broadening. It is recommended that the GC column
be fitted directly into the MS source. Graphic
ferrules should be avoided in the GC injection area
since they may adsorb PAHs. Vespel® or equivalent
ferrules are recommended.
8.3.2.3 Mass Spectrometer. The static resolution of the in-
strument must be maintained at a minimum of 10,000
(10 percent valley). The mass spectrometer should
be operated in the selected ion mode (SIM) with a total
cycle time (including voltage reset time) of one
second or less (Section 14.2).
8.3.2.4 Mass spectrometer: Capable of scanning from 35 to
500 amu every 1 sec or less, using 70 volts
(nominal) electron energy in the electron impact
ionization mode. The mass spectrometer must be
capable of producing a mass spectrum for decafluoro-
triphenylphosphine (DFTPP) which meets all of the
criteria (Section 14.5.1).
8.3.2.5 Data System. A dedicated computer data system
is employed to control the rapid multiple ion
monitoring process and to acquire the data.
Quantification data (peak areas or peak heights)
and multi-ion detector (MID) traces (displays
of intensities of each m/z being monitored
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T013-13
as a function of time) must be acquired during the
analyses. Quantifications may be reported based
upon computer-generated peak areas or upon measured
peak heights (chart recording). The detector zero
setting must allow peak-to-peak measurement of the
noise on the baseline.
8.3.2.6 GC Column. A fused silica column (50-m x 0.25-mm
I.D.) HP Ultra #2 crosslinked 5% phenyl methylsili-
cone, 0.25 urn film thickness (Hewlett-Packard Co.,
Crystal Lake, IL) is utilized to separate individual
PAHs. Other columns may be used for determination
of PAHs. Minimum acceptance criteria must be deter-
mined as per Section 14.2. At the beginning of each
12-hour period (after mass resolution has been demon-
strated) during which sample extracts or concentra-
tion calibration solutions will be analyzed, column
operating conditions must be attained for the required
separation on the column to be used for samples.
8.3.2.7 Balance - Mettler balance or equivalent.
8.3.2.8 All required syringes, gases, and other pertinent
supplies to operate the GC/MS system.
8.3.2.9 Pipettes, micropipettes, syringes, burets, etc., to
make calibration and spiking solutions, dilute samples
if necessary, etc., including syringes for accurately
measuring volumes such as 25 uL and 100 uL.
8.3.3 High Performance Liquid Chromatography (HPLC) System.
8.3.3.1 Gradient HPLC system - Consisting of acetonitrile and
water phase reservoirs; mixing chamber; a high pres-
sure pump; an injection valve (automatic sampler
with an optional 25 uL loop injector); a Vydac C-18
bonded phase reverse phase (RP) column, (The Separa-
tions Group, P.O. Box 867, Hesperia, CA 92345) or
equivalent (25-cm x 4.6-mm ID); a variable wavelength
UV/Fluorescence detector and a data system or strip
chart recorder. A Spectra Physics 8100 liquid chromat-
ograph multi-microprocessor controlled, with ternary
gradient pumping system, constant flow, autosampler
injector (10 uL injection loop), and column oven
(optional).
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8.3.3.2 Guard column - 5-cm guard column pack with Vydac
reverse phase C-18 material.
8.3.3.3 Reverse phase analytical column - Vydac or equivalent,
C-18 bonded phase RP column (The Separation Group,
P.O. Box 867, Hesperia, Ca., 92345), 4.6-mm x 25-cm,
5-micron particle diameter.
8.3.3.4 LS-4 fluorescence spectrometer, Perkin Elmer, sepa-
ate excitation and emission, monochromator positioned
by separate microprocessor-controlled flow cell and
wavelength programming ability (optional).
8.3.3.5 Ultraviolet/visible detector, Spectra Physics 8440,
deuterium Lamp, capable of programmable wavelengths
(optional).
8.3.3.6 Dual channel Spectra Physics 4200 Computing Integra-
tor, measures peak areas and retention times from
recorded chromatographs. IBM PC XT will Spectra
Physics Labnet system for data collection and storage
(optional).
9. Reagents and Materials
9.1 Sample Collection
9.1.1 Acid-washed quartz fiber filter - 105 mm micro quartz fiber
binderless filter (General Metal Works, Inc., Cat. No. GMW
QMA-4, 145 South Miami Ave., Village of Cleves, Ohio,
45002 [800-543-7412] or Supeico Inc., Cat. No. 1-62,
Supeico Park, Bellefonte, PA, 16823-0048).
9.1.2 Polyurethane foam (PUT) - 3 inch thick sheet stock,
polyether type (density 0.022 g/cm3) used in furniture
upholstering (General Metal Works, Inc., Cat. No. PS-1-16,
145 South Miami Ave., Village of Cleves, Ohio, 45002 [800-
543-7412] or Supeico Inc., Cat. No. 1-63, Supeico Park,
Bellefonte, PA, 16823-0048).
9.1.3 XAD-2 resin - Supeico Inc., Cat. No. 2-02-79, Supeico
Park, Bellefonte, PA, 16823-0048.
9.1.4 Hexane-rinsed aluminum foil - best source.
9.1.5 Hexane-reagent grade, best source.
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9.2 Sample Clean-up and Concentration
9.2.1 Soxhlet Extraction
9.2.1.1 Methylene chloride - chromatographic grade,
glass-distilled, best source.
9.2.1.2 Sodium sulfate, anhydrous - (ACS) granular
anhydrous (purified by washing with methylene
chloride followed by heating at 400°C for 4 hrs
in a shallow tray).
9.2.1.3 Boiling chips - solvent extracted, approximately
10/40 mesh (silicon carbide or equivalent).
9.2.1.4 Nitrogen - high purity grade, best source.
9.2.1.5 Ether - chromatographic grade, glass-distilled,
best source.
9.2.1.6 Hexane - chromatographic grade, glass-distilled,
best source.
9.2.1.7 Dibromobiphenyl - chromatographic grade, best source,
Used for internal standard.
9.2.1.8 Decafluorobiphenyl - chromatographic grade, best
source. Used for internal standard.
9.2.2 Solvent Exchange
9.2.2.1 Cyclohexane - chromatographic grade, glass-
distilled, best source.
9.2.3 Column Clean-up
Method 610
9.2.3.1 Silica gel - high purity grade, type 60, 70-230
mesh; extracted in a Soxhlet apparatus with
methylene chloride for 6 hours (minimum of 3
cycles per hour) and activated by heating in a
foil-covered glass container for 24 hours at 130°C.
9.2.3.2 Sodium sulfate, anhydrous - (ACS) granular
anhydrous (See Section 9.2.1.2).
9.2.3.3 Pentane - chromatographic grade, glass-distilled,
best source.
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Lobar Prepacked Column
9.2.3.4 Silica gel lobar prepacked column - E. Merck,
Darmstadt, Germany [Size A(240-10) Lichroprep Si
(40-63 urn)].
9.2.3.5 Precolumn containing sodium sulfate - American
Chemical Society (ACS) granular anhydrous (purified
by washing with methylene chloride followed by
heating at 400°C for 4 hours in a shallow tray).
9.2.3.6 Hexane - chromatographic grade, glass-distilled,
best source.
9.2.3.7 Methylene chloride - chromatographic grade, glass-
distilled, best source
9.2.3.8 Methanol - chromatographic grade, glass-distilled,
best source.
9.3 Sample Analysis
9.3.1 Gas Chromatography Detection
9.3.1.1 Gas cylinders of hydrogen and helium - ultra high
purity, best source.
9.3.1.2 Combustion air - ultra high purity, best source.
9.3.1.3 Zero air - Zero air may be obtained from a cylinder
or zero-grade compressed air scrubbed with Drierite®
or silica gel and 5A molecular sieve or activated
charcoal, or by catalytic cleanup of ambient air.
All zero air should be passed through a liquid
argon cold trap for final cleanup.
9.3.1.4 Chromatographic-grade stainless steel tubing
and stainless steel plumbing fittings - for
interconnections. [Alltech Applied Science,
2051 Waukegan Road, Deerfield, IL, 60015, (312)
948-8600]. [Note: Al1 such materials in contact
with the sample, analyte, or support gases prior
to analysis should be stainless steel or other
inert metal. Do not use plastic or Teflon®
tubing or fittings.]
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9.3.1.5 Native and isotopically labeled PAHs isomers for
calibration and spiking standards-CCambridge
Isotopes, 20 Commerce Way, Woburn, MA, 01801 (617-
547-1818)]. Suggested isotopically labeled PAH
isomers are:
o perylene - d\2
o chrysene - d^2
o acenaphthene -
o naphthalene -
o phenanthrene -
9.3.1.6 Decafluorotriphenylphosphine (DFTPP) - best source,
used for tuning GC/MS.
9.3.2 High Performance Liquid Chromatography Detection
9.3.2.1 Acetonitrile - chromatographic grade, glass-
distilled, best source.
9.3.2.2 Boiling chips - solvent extracted, approximatley
10/40 mesh (silicon carbide or equivalent).
9.3.2.3 Water - HPLC Grade. Water must not have an
interference that is observed at the minimum
detectable limit (MDL) of each parameter of interest.
9.3.2.4 Decafluorobiphenyl - HPLC grade, best source
(used for internal standard).
10. Preparation of Sample Filter and Adsorbent
10.1 Sampling Head Configuration
10.1.1 The sampling head (Figure 2) consist of a filter holder
compartment followed by a glass cartridge for retaining
the adsorbent.
10.1.2 Before field use, both the filter and adsorbent must be
cleaned to <10 ng/apparatus of B[a]P or other PAHs.
10.2 Glass Fiber Filter Preparation
10.2.1 The glass fiber filters are baked at 600°C for five hours
before use. To insure acceptable filters, they are ex-
tracted with methylene chloride in a Soxhlet apparatus, sim-
ilar to the cleaning of the XAD-2 resin (see Section 10.3).
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10.2.2 The extract is concentrated and analyzed by either GC or
HPLC. A filter blank of <10 ng/filter of B[a]P or other
PAHs is considered acceptable for field use.
10.3. XAD-2 Adsorbent Preparation
10.3.1 For initial cleanup of the XAD-2, a batch of XAD-2 (approxi-
mately 60 grams) is placed in a Soxhlet apparatus [see Fig-
ure 3(a)] and extracted with methylene chloride for 16
hours at approximately 4 cycles per hour.
10.3.2 At the end of the initial Soxhlet extraction, the spent
methylene chloride is discarded and replaced with fresh
reagent. The XAD-2 resin is once again extracted for 16
hours at approximately 4 cycles per hour.
10.3.3 The XAD-2 resin is removed from the Soxhlet apparatus,
places in a vacuum oven connected to an ultra-purge nitrogen
gas stream and dries at room temperature for approximately
2-4 hours (until no solvent odor is detected).
10.3.4 A nickel screen (mesh size 200/200) is fitted to the bottom
of a hexane-rinsed glass cartridge to retain the XAD-2 resin.
10.3.5 The Soxhlet extracted/vacuum dried XAD-2 resin is placed into
the sampling cartridge (using polyester gloves) to a depth
of approximately 2 inches. This should require approxi-
mately 55 grams of adsorbent.
10.3.6 The glass module containing the XAD-2 adsorbent is wrapped
with hexane-rinsed aluminum foil, placed in a labeled
container and tightly sealed with Teflon® tape.
10.3.7 At least one assemble cartridge from each batch must be
analyzed, as a laboratory blank, using the procedures
described in Section 13, before the batch is considered
acceptable for field use. A blank of <10 ng/cartridge of
B[a]P on other PNA's is considered acceptable.
10.4 PDF Sampling Cartridge Preparation
10.4.1 The PUF adsorbent is a polyether-type polyurethane foam
(density No. 3014 or 0.0225 g/cm3) used for furniture up-
holstery.
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10.4.2 The PUF inserts are 6.0-cm diameter cylindrical plugs cut
from 3-inch sheet stock and should fit, with slight
compression, in the glass cartridge, supported by the
wire screen (see Figure 1). During cutting, the die is
rotated at high speed (e.g., in a drill press) and
continuously lubricated with water.
10.4.3 For initial cleanup, the PUF plug is placed in a Soxhlet
apparatus [see Figure 3(a)] and extracted with acetone
for 14-24 hours at approximately 4 cycles per hour.
[Note: When cartridges are reused, 5% diethyl ether in
n-hexane can be used as the cleanup solvent.]
10.4.4 The extracted PUF is placed in a vacuum oven connected to
a water aspirator and dried at room temperature for
approximately 2-4 hours (until no solvent odor is detected).
10.4.5 The PUF is placed into the glass sampling cartridge using
polyester gloves. The module is wrapped with hexane-
rinsed aluminum foil, placed in a labeled container, and
tightly sealed.
10.4.6 At least one assembled cartridge from each batch must be
analyzed, as a laboratory blank, using the procedures
described in Section 13, before the batch is considered
acceptable for field use. A blank level of <10 ng/plug
for single compounds is considered to be acceptable.
11. Sample Collection
11.1 Description of Sampling Apparatus
11.1.1 The entire sampling system can be a modification of a
traditional high volume sampler (see Figure 4) or a portable
sampler (see Figure 5). A unit specifically designed for
this method is commercially available (Model PS-1 -
General Metal Works, Inc., Village of Cleves, Ohio).
11.1.2 The sampling module consists of a glass sampling cartridge
and an air-tight metal cartridge holder, as outlined in
Section 10.1. The adsorbent (XAD-2 or PUF) is retained
in the glass sampling cartridge.
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11.2 Calibration of Sampling System
Each sampler is to be calibrated: 1) when new; 2) after major
repairs or maintenance; 3) whenever any audit point deviates
from the calibration curve by more than 7%; 4) when a different
sample collection media, other than that which the sampler was
originally calibrated to, will be used for sampling; or 5) at the
frequency specified in the user Standard Operating Procedure (SOP)
manual in which the samplers are utilized.
11.2.1 Calibration of Flow Rate Transfer Standard
Calibration of the modified high volume air sampler in
the field is performed using a calibrated orifice flow
rate transfer standard. The flow rate transfer standard
must be certified in the laboratory against a positive
displacement rootsmeter (see Figure 6). Once certified,
the recertification is performed rather infrequently if
the orifice is protected from damage. Recertification
of the orifice flow rate transfer standard is performed
once per year utilizing a set of five (5) multihole re-
sistance plates. [Note: The 5 multihole resistance
plates are used to change the flow through the orifice so
that several points can be obtained for the orifice cali-
bration curve.]
11.2.1.1 Record the room temperature (tj in °C) and barome-
tric pressure (P& in mm Hg) on Orifice Calibra-
tion Data Sheet (see Figure 7). Calculate the
room temperature in °K (absolute temperature)
and record on Orifice Calibration Data Sheet.
ti in K = 273° + ti in °C
11.2.1.2 Set up laboratory orifice calibration equipment
as illustrated in Figure 6. Check the oil level
of the rootsmeter prior to starting. There are
three oil level indicators, one at the clear
plastic end, and two sight glasses, one at each
end of the measuring chamber.
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11.2.1.3 Check for leaks by clamping both manometer lines
blocking the orifice with cellophane tape, turning
on the high volume motor, and noting any change
in the rootsmeter's reading. If the rootsmeter's
reading changes, then there is a leak in the sys-
tem or in the tape. Eliminate the leak before
proceeding. If the rootsmeter's reading remains
constant, turn off the hi-vol motor, remove the
cellophane tape, and unclamp both manometer lines.
11.2.1.4 Install the 5-hole resistance plate between the
orifice and the filter adapter.
11.2.1.5 Turn manometer tubing connectors one turn counter-
clockwise. Make sure all connectors are open.
11.2.1.6 Adjust both manometer midpoints by sliding their
movable scales until the zero point corresponds
with the bottom of the meniscus. Gently shake
or tap to remove any air bubbles and/or liquid
remaining on tubing connectors. (If additional
liquid is required for the water manometer,
remove tubing connector and add clean water).
11.2.1.7 Turn on the hi-vol motor and let it run for
five minutes to set the motor brushes.
11.2.1.8 Record both manometer readings-orifice water mano-
meter (AH) and rootsmeter mercury manometer (AP).
[Note: AH is the sum of the difference from zero
(0) of the two column heights.]
11.2.1.9 Record the time, in minutes, required to pass a
known volume of air (approximately 200-300 ft3 of
air for each resistance plate) through the roots-
meter by using the rootsmeter's digital volume dial
and a stopwatch.
11.2.1.10 Turn off the high volume motor.
11.2.1.11 Replace the 5-hole resistance plate with the 7-
hole resistance plate.
11.2.1.12 Repeat Sections 11.2.1.3 through 11.2.1.10.
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T013-22
11.2.1.13 Repeat for each resistance plate. Note results
on Orifice Calibration Data Sheet (see Figure 7).
Only a minute is needed for warm-up of the motor.
Be sure to tighten the orifice enough to elimi-
nate any leaks. Also check the gaskets for
cracks. [Note: The placement of the orifice
prior to the rootsmeter causes the pressure at
the inlet of the rootsmeter to be reduced below
atmospheric conditions, thus causing the measured
volume to be incorrect. The volume measured
by the rootsmeter must be corrected.]
11.2.1.14 Correct the measured volumes with the following
formula and record the standard volume on the
Orifice Calibration Data Sheet:
Vstd = Vm Pi -AP Tstd
Pstd T!
o
where: Vg^ = standard volume (std m ).
Vm = actual volume measured by the
rootsmeter (m^).
P! = barometric pressure during cali-
bration (mm Hg).
AP = differential pressure at inlet
to volume meter (mm Hg).
Pstd = 760 mm Hg.
Tstd = 298 K.
TI = ambient temperature during cali-
bration (K).
11.2.1.15 Record standard volume on Orifice Calibration
Data Sheet.
11.2.1.16 The standard flow rate as measured by the
rootsmeter can now be calculated using the
following formula:
Qstd = Vstd
9
where: Q$td = standard volumetric flow rate,
std m3/min.
9 = elapsed time, min.
-------
T013-23
11.2.1.17 Record the standard flow rates to the nearest
0.01 std m3/min.
11.2.1.18 Calculate and record \AH(Pi/Pstd) (298/Ti)
value for each standard flow rate.
11.2.1.19 Plot each ^AH(Pi/Pstd) (298/T!) value (y-axis)
versus its associated standard flow rate (x-axis)
on arithmetic graph paper, draw a line of best
fit between the individual plotted points and
calculate the linear regression slope (M) and
intercept (b).
11.2.1.20 Commercially available calibrator kits are
available [General Metal Works Inc., Model
GMW-40, 145 South Miami Avenue, Village of
Cleves, Ohio, 45002 (1-800-543-7412)].
11.2.2 Calibration of The High Volume Sampling System Utilizing
Calibrated Multi-point Flow Rate Transfer Standard
11.2.2.1 The airflow through the sampling system can be
monitored by a venturi/magnehelic assembly, as
illustrated in Figure 4 or by a u-tube assembly
connected to the high volume portable design as
illustrated in Figure 5. The field sampling sys-
tem must be audited every six months using a
flow rate transfer standard, as described in the
U.S. EPA High Volume Sampling Method, 40 CFR 50,
Appendix B. A single-point calibration must be
performed before and after each sample collec-
tion, using a transfer standard calibrated as
described in Section 11.2.1.
11.2.2.2 Prior to initial multi-point calibration, a
"dummy" adsorbent cartridge and filter are
placed in the sampling head and the sampling
motor is activated. The flow control valve
is fully opened and the voltage variator is
adjusted so that a sample flow rate corresponding
to 110% of the desired flow rate (typically
0.20 - 0.28 m3/min) is indicated on the
Magnehelic gauge (based on the previously
obtained multi-point calibration curve). The
-------
T013-24
motor is allowed to warm up for 10 minutes and
then the flow control valve is adjusted to
achieve the desired flow rate. Turn off the
sampler. The ambient temperature and baro-
metric pressure should be recorded on the Field
Calibration Data Sheet (Figure 9).
11.2.2.3 The flow rate transfer standard is placed on
the sampling head, and a manometer is connected
to the tap on the transfer standard using a
length of tubing. Properly align the retaining
rings with filter holder and secure by tighten-
ing the three screw clamps. Set the zero
level of the manometer. Attach the magnehelic
gage to the sampler venturi quick release
connections. Adjust the zero (if needed)
using the zero adjust screw on the face of
the gage.
11.2.2.4 Turn the flow control valve to the fully open
position and turn the sampler on. Adjust the
flow control valve until a magnehelic reading
of approximately 70 in. is obtained. Allow
the magnehelic and manometer readings to
stabilize and record these values.
11.2.2.5 Adjust the flow control valve and repeat until
six or seven uniformally spaced magnehelic
readings are recorded spanning the range of
approximately 40-70 in. Record the readings
on the Field Calibration Data Sheet (see
Figure 9). [Note: Use of some filter/sorbent
media combinations may restrict the airflow
resulting in a maximum magnehelic reading of
60 in. or less. In such cases, a variable
transformer should be placed in-line between
the 110 volt power source and the sampler so
that the line voltage can be increased suf-
ficiently to obtain a maximum magnehelic
reading approaching 70 in.].
-------
T013-25
11.2.2.6 Adjust the orifice manometer reading for standard
temperature and pressure using the following
equation:
X =
-------
TO13-26
Mstd •
where:
V(M)(Pa)
Pstd
Tstd
Ta
Mstd = adjusted magnehelic reading to
standard temperature and pressure
(inches of water).
M = observed magnehelic reading
(inches of water).
Pa = ambient atmospheric pressure (mm Hg).
Pstd = standard pressure (760 mm Hg).
Ta = ambient temperature (K), (K = °C + 273),
Tstd = standard temperature (298 K).
11.2.2.9 Plot each Mstd value (y-axis) versus its
associated Qstd standard (x-axis) on arithmetic
graph paper. Draw a line of best fit between
the individual plotted points. This is the
calibration curve for the venturi. Retain with
sampler.
11.2.2.10 Record the corresponding Qstd for each Mstd
under Qstd column on Field Calibration Data
Sheet, Figure 9.
11.2.3 Single-point Audit of The High Volume Sampling System
Utilizing Calibrated Flow Rate Transfer Standard
11.2.3.1 A single point flow audit check is performed
before and after each sampling period utilizing
the Calibration Flow Rate Transfer Standard
(Section 11.2.1).
11.2.3.2 Prior to single point audit, a "dummy" adsorbent
cartridge and filter are placed in the sampling
head and the sampling motor is activated.
The flow control valve is fully opened and
the voltage variator is adjusted so that a
-------
T013-27
sample flow rate corresponding to 110% of the
desired flow rate (typically 0.20-0.28 m3/min)
is indicated on the magnehelic gauge (based on
the previously obtained multi-point calibration
curve). The motor is allowed to warm up for 5
minutes and then the flow control valve is
adjusted to achieve the desired flow rate.
Turn off the sampler. The ambient temperature
and barometric pressure should be recorded on
a Field Test Data Sheet (Figure 10).
11.2.3.3 The flow rate transfer standard is placed on
the sampli ng head.
11.2.3.4 Properly align the retaining rings with filter
holder and secure by tightening the three screw
clamps.
11.2.3.5 Using tubing, attach one manometer connector to
the pressure tap of the transfer standard. Leave
the other connector open to the atmosphere.
11.2.3.6 Adjust the manometer midpoint by sliding the
movable scale until the zero point corresponds
with the water meniscus. Gently shake or tap
to remove any air bubbles and/or liquid remain-
ing on tubing connectors. (If additional liquid
is required, remove tubing connector and add
clean water.)
11.2.3.7 Turn on high volume motor and let run for five
minutes.
11.2.3.8 Record the pressure differential indicated, AH,
in inches of water. Be sure stable AH has been
established.
11.2.3.9 Record the observed magnehelic gauge reading,
in inches of water. Be sure stable M has been
establi shed.
-------
T013-28
11.2.3.10 Using previously established Flow Rate Transfer
Standard curve, calculate Qg^d (see steps
11.2.2.6 - 11.2.2.7).
11.2.3.11 Using previously established venturi calibration
curve, calculate the indicated QS^J (Section
11.2.2.9).
11.2.3.12 A multi-point calibration of the Flow Rate
Transfer Standard against a primary standard,
must be obtained annually, as outlined in
Section 11.2.1.
11.2.3.13 Remove Flow Rate Transfer Standard and dummy
adsorbent cartridge and filter assembly.
11.3 Sample Collection
11.3.1 After the sampling system has been assembled and flow check-
ed as described in Sections 11.1 and 11.2, it can be used to
collect air samples, as described in Section 11.3.2.
11.3.2 The samples should be located in an unobstructed area, at
least two meters from any obstacle to air flow. The exhaust
hose should be stretched out in the downwind direction to
prevent recycling of air into the sample head.
11.3.3 With the empty sample module removed from the sampler,
rinse all sample contact areas using reagent grade hexane
in a Teflon® squeeze bottle. Allow the hexane to evaporate
from the module before loading the samples.
11.3.4 Detach the lower chamber of the rinsed sampling module.
While wearing disposable clean lint-free nylon or powder-
free surgical gloves, remove a clean glass cartridge/sorbent
from its container (wide mouthed glass jar with a Teflon®-
lined lid) and unwrap its aluminum foil covering. The foil
should be replaced back in the sample container to be re-
used after the sample has been collected.
11.3.5 Insert the cartridge into the lower chamber and tightly
reattach it to the module.
11.3.6 Using clean Teflon® tipped forceps, carefully place a clean
fiber filter atop the filter holder and secure in place
by clamping the filter holder ring over the filter using
the three screw clamps. Insure that all module connec-
tions are tightly assembled. [Note: Failure to do so
-------
T013-29
could result in air flow leaks at poorly sealed locations
which could affect sample representativeness]. Ideally,
sample module loading and unloading should be conducted
in a controlled environment or at least a centralized
sample processing area so that the sample handling vari-
ables can be minimized.
11.3.7 With the module removed from the sampler and the flow
control valve fully open, turn the pump on and allow it
to warm-up for approximately 5 minutes.
11.3.8 Attach a "dummy" sampling module loaded with the exact
same type of filter and sorbent media as that which
will be used for sample collection.
11.3.9 With the sampler off, attach the Magnahelic gage to the
sampler. Turn the sampler on and adjust the flow control
valve to the desired flow (normally as indicated by the
cfm) magnahelic gauge reading and reference by the
calibration chart. [Note: Breakthrough has not been a
problem for all PAHs outlined in Section 1.5 using
this sampling method except anthracene and penanthrene].
Once the flow is properly adjusted, extreme care should
be taken not to inadvertantly alter its setting.
11.3.10 Turn the smpler off and remove both the "dummy" module
and the Magnahelic gauge. The sampler is now ready for
field use.
11.3.11 The zero reading of the sampler Magnehelic is checked.
Ambient temperature, barometric pressure, elapsed time
meter setting, sampler serial number, filter number,
and adsorbent sample number are recorded on the Field
Test Data Sheet (see Figure 10). Attach the loaded
sampler module to the sampler.
11.3.12 The voltage variator and flow control valve are placed
at the settings used in Section 11.2.2, and the power
switch is turned on. The elapsed time meter is acti-
vated and the start time is recorded. The flow (Magne-
helic setting) is adjusted, if necessary, using the
flow control valve.
11.3.13 The Magnehelic reading is recorded every six hours
during the sampling period. The calibration curve
-------
T013-30
(Section 11.2.4) is used to calculate the flow rate.
Ambient temperature, barometric pressure, and Magnehe-
lic reading are recorded at the beginning and end of
the sampling period.
11.3.14 At the end of the desired sampling period, the power is
turned off. Carefully remove the sampling head contain-
ing the filter and adsorbent cartridge to a .clean area.
11.3.15 While wearing disposable lint free nylon or surgical
gloves, remove the sorbent cartridge from the lower
module chamber and lay it on the retained aluminum foil
in which the sample was originally wrapped.
11.3.16 Carefully remove the glass fiber filter from the upper
chamber using clean Teflon® tiped forceps.
11.3.17 Fold the filter in half twice (sample side inward) and
place it in the glass cartridge atop the sorbent.
11.3.18 Wrap the combined samples in aluminum foil and place them
in their original glass sample container. A sample label
should be completed and affixed to the sample container.
Chain-of-custody should be maintained for all samples.
11.3.19 The glass containers should be stored in ice and pro-
tected from light to prevent possible photo-decomposi-
tion of collected analytes. If the time span between
sample collection and laboratory analysis is to exceed
24 hours, sample must be kept refrigerated. [Note: Recent
studies (13,16) have indicated that PDF does not retain,
during storage, B[a]P as effectively as XAD-2. Therefore,
sample holding time should not exceed 20 days.]
11.3.20 A final calculated sample flow check is performed using
the calibration orifice, as described in Section 11.2.2.
If calibration deviates by more than 10% from the initial
reading, the flow data for that sample must be marked
as suspect and the sampler should be inspected and/or
removed from service.
11.3.21 At least one field filter/adsorbent blank will be re-
turned to the laboratory with each group of samples. A
field blank is treated exactly as a sample except that
no air is drawn through the filter/adsorbent cartridge
assembly.
-------
T013-31
11.3.22 Samples are stored at 0°C in an ice chest until receipt
at the analytical laboratory, after which they are
refrigerated at 4°C.
12. Sample Clean-up and Concentration
[Note: The following sample extraction, concentration, solvent exchange
and analysis procedures are outlined for user convenience in Figure 11.]
12.1 Sample Identification
12.1.1 The samples are returned in the ice chest to the laboratory
in the glass sample container containing the filter and
adsorbent.
12.1.2 The samples are logged in the laboratory logbook according
to sample location, filter and adsorbent cartridge number
identification and total air volume sampled (unconnected).
12.1.3 If the time span between sample registration and analysis
is greater than 24-hrs., then the samples must be kept
refrigerated. Minimize exposure of samples to fluores-
cence light. All samples should be extracted within one
week after sampling.
12.2 Soxhlet Extraction and Concentration
12.2*1 Assemble the Soxhlet apparatus [see Figure 3(a)]. Immedi-
ately before use, charge the Soxhlet apparatus with 200 to
250 ml of methylene chloride and reflux for 2 hours. Let
the apparatus cool, disassemble it, transfer the methylene
chloride to a clean glass container, and retain it as a
blank for later analysis, if required. Place the adsorbent
and filter together in the Soxhlet apparatus (the use of an
extraction thimble is optional) if using XAD-2 adsorbent in
the sampling module. [Note: The filter and adsorbent are
analyzed together in order to reach detection limits, avoid
questionable interpretation of the data, and minimize cost.]
Since methylene chloride is not a suitable solvent for PDF,
10% ether in hexane is employed to extract the PAHs from
the PUT resin bed separate from the methylene chloride
extraction of the accompanying filter rather than methylene
chloride for the extraction of the XAD-2 cartridge.
12.2.1.1 Prior to extraction, add a surrogate standard to
the Soxhlet solvent. A surrogate standard (i.e.,
a chemically inert compound not expected to
-------
T013-32
occur in an environmental sample) should be
added to each sample, blank, and matrix spike
sample just prior to extraction or processing.
The recovery of the surrogate standard is used
to monitor for unusual matrix effects, gross
sample processing errors, etc. Surrogate recov-
ery is evaluated for acceptance by determining
whether the measured concentration falls within
the acceptance limits. The following surrogate
standards have been successfully utilized in
determining matrix effects, sample process errors,
etc. utilizing GC/FID, GC/MS or HPLC analysis.
Surrogate Analytical
Standard Concentration Technique
Dibromobiphenyl 50 ng/uL GC/FID
Dibromobiphenyl 50 ng/uL GC/MS
Deuterated Standards 50 ng/uL GC/MS
Decafluorobiphenyl 50 ng/uL HPLC
[Note: The deuterated standards will be added
in Section 14.3.2. Deuterated analogs of selec-
tive PAHs cannot be used as surrogates for HPLC
analysis due to coelution problems.] Add the
surrogate standard to the Soxhlet solvent.
12.2.1.2 For the XAD-2 and filter extracted together,
add 300 mL of methylene chlorine to the apparatus
and reflux for 18 hours at a rate of at least
3 cycles per hour.
12.2.1.3 For the PUF extraction separate from the filter,
add 300 mL of 10 percent ether in hexane to the
apparatus and reflux for 18 hours at a rate of
at least 3 cycles per hour.
12.2.1.4 For the filter extraction, add 300 mL of methylene
chloride to the apparatus and reflux for 18 hours
at a rate of at least 3 cycles per hour.
12.2.2 Dry the extract from the Soxhlet extraction by passing it
through a drying column containing about 10 grams of anhy-
drous sodium sulfate. Collect the dried extract in a
Kuderna-Danish (K-D) concentrator assembly. Wash the
-------
T013-33
extractor flask and sodium sulfate column with 100 - 125 ml
of methylene chloride to complete the quantitative transfer.
12.2.3 Assemble a Kuderna-Danish concentrator [see Figure 3(b)]
by attaching a 10 ml concentrator tube to a 500 ml evapora-
tive flask. [Note: Other concentration devices (vortex
evaporator) or techniques may be used in place of the K-D
as long as qualitative and quantitative recovery can be
demonstrated.]
12.2.4 Add two boiling chips, attach a three-ball macro-Snyder
column to the K-D flask, and concentrate the extract using
a water bath at 60 to 65°C. Place the K-D apparatus in ,
the water bath so that the concentrator tube is about half
immersed in the water and the entire rounded surface of
the flask is bathed with water vapor. Adjust the vertical
position of the apparatus and the water temperature as
required to complete the concentration in one hour. At
the proper rate of distillation, the balls of the column
actively chatter but the chambers do not flood. When the
liquid has reached an approximate volume of 5 ml_, remove the
K-D apparatus from the water bath and allow the solvent
to drain for at least 5 minutes while cooling.
12.2.5 Remove the Snyder column and rinse the flask and its lower
joint into the concentrator tube with 5 ml of cyclohexane.
12.3 Solvent Exchange
12.3.1 Replace the K-D apparatus equipped with a Snyder column
back on the water bath.
12.3.2 Increase the temperature of the hot water bath to 95-100°C.
Momentarily, remove the Snyder column, add a new boiling
chip, and attach a two-ball micro-Snyder column. Prewet
the Snyder column, using 1 ml of cyclohexane. Place the
K-D apparatus on the water bath so that the concentrator
tube is partially immersed in the hot water. Adjust the
vertical position of the apparatus and the water tempera-
ture, as required, to complete concentration in 15-20
minutes. At the proper rate of distillation, the balls
of the column will actively chatter, but the chambers
-------
T013-34
will not flood. When the apparent volume of liquid
reaches 0.5 ml, remove the K-D apparatus and allow it to
drain and cool for at least 10 minutes.
12.3.3 When the apparatus is cool, remove the micro-Snyder
column and rinse its lower joint into the concentrator
tube with about 0.2 ml of cyclohexane. [Note: A 5 ml
syringe is recommended for this operation]. Adjust the
extract volume to exactly 1.0 mL with cyclohexane. Stopper
the concentrator tube and store refrigerated at 4°C, if
further processing will not be performed immediately. If
the extract will be stored longer than 24 hours, it should
be transferred to a Teflon®-sealed screw-cap vial.
12.4 Sample Cleanup By Solid Phase Exchange
Cleanup procedures may not be needed for relatively clean matrix
samples. If the extract in Section 12.3.3 is clear, cleanup may
not be necessary. If cleanup is not necessary, the cyclohexane
extract ( 1 ml) can be analyzed directly by GC/FI detection, except
the initial oven temperature begins at 30°C rather than 80°C for
cleanup samples (see Section 13.3), or solvent exchange to aceton-
itrile for HPLC analysis. If cleanup is required, the procedures
are presented using either handpack silica gel column as prescribed
in Method 610 (see Section 18.0, citation No. 18 and 22) or the
use of a Lobar prepacked silica gel column for PAH concentration
and separation. Either approach can be employed by the user.
12.4.1 Method 610 Cleanup Procedure [see Figure 3(c)]
12.4.1.1 Pack a 6-inch disposable Pasture pipette
(10 mm I.D.-x 7 cm length) with a piece of
glass wool. Push the wool to the neck of the
disposable pipette. Add 10 grams of activated
silica gel in methylene chloride slurry to the
disposable pipette. Gently tap the column to
settle the silica gel and elute the methylene
chloride. Add 1 gram of anhydrous sodium sul-
fate to the top of the silica gel column.
12.4.1.2 Prior to initial use, rinse the column with
methylene chloride at 1 mL/min for 1 hr to
-------
T013-35
remove any trace of contaminants. Preelute the
column with 40 ml of pentane. Discard the eluate
and just prior to exposure of the sodium sulfate
layer to the air, transfer the 1 ml of the cyclo-
hexane sample extract onto the column, using an
additional 2 ml of cyclohexane to complete the
transfer. Allow to elute through the column.
12.4.1.3 Just prior to exposure of the sodium sulfate
layer to the air, add 25 ml of pentane and con-
tinue elution of the column. Discard the pen-
tane eluate. [Note: The pentane fraction
contains the aliphatic hydrocarbons collected
on the filter/ adsorbent combination. If inter-
ested, this fraction may be analyzed for specific
aliphatic organics.] Elute the column with 25 ml
of methylene chloride/pentane (4 +6) (V/V) and
collect the eluate in a 500 ml K-D flask equipped
with a 10 ml concentrator tube. [Note: This
fraction contains the B[a]P and other moderately
polar PAHs]. Elution of the column should be
at a rate of about 2 mL/min. Concentrate the
collected fraction to less than 10 ml by the
K-D technique, as illustrated in Section 12.3
using pentane to rinse the walls of the glass-
ware. The extract is now ready for HPLC or GC
analysis. [Note: An additional elution through
the column with 25 mL of methanol will collect
highly polar oxygenated PAHs with more than one
functional group. This fraction may be analyzed
for specific polar PAHs. However, additional
cleanup by solid phase extraction may be required
to obtain both qualitative and quantitative data
due to complexity of the eluant.]
12.4.2 Lobar Prepacked Column Procedure
12.4.2.1 The setup using the Lobar prepacked column con-
sists of an injection port, septum, pump, pre-
column containing sodium sulfate, Lobar prepacked
column and solvent reservoir.
-------
T013-36
12.4.2.2 The column is cleaned and activated according
to the following cleanup sequence:
Fraction Solvent Composition Volume (ml)
1 100% Hexane 20
2 80% Hexane/20% Methylene Chloride 10
3 50% Hexane/50% Methylene Chloride 10
4 100% Methylene Chloride 10
5 95% Methylene Chloride/5% Methanol 10
6 80% Methylene Chloride/20% Methanol 10
12.4.2.3 Reverse the sequence at the end of the run and
run to the 100% hexane fraction in order to
activate the column. Discard all fractions.
12.4.2.4 Pre-elute the column with 40 ml of hexane,
which is also discharged.
12.4.2.5 Inject 1 ml of the cyclohexane sample extract,
followed by 1 ml injection of blank cyclohexane.
12.4.2.6 Continue elution of the column with 20 ml of
hexane, which is also discharged.
12.4.2.7 Now elute the column with 180 mL of a 40/60
mixture of methylene chloride/hexane respectively.
12.4.2.8 Collect approximately 180 ml of the 40/60 methy-
lene chloride/hexane mixture in a K-D concentrator
assembly.
12.4.2.9 Concentrate to less than 10 ml with the K-D
assembly as discussed in Section 12.2.
12.4.2.10 The extract is now ready for either HPLC or
GC analysis.
13. Gas Chromatography Analysis with Flame lonization Detection
13.1 Gas Chromatography (GC) is a quantitative analytical technique
useful for PAH identification. This method provides the user the
flexibility of column selection (packed or capillary) and detector
[flame ionization (FI) or mass spectrometer (MS)] selection. The
mass spectrometer provides for specific identification of B(a)P;
however, with system optimization, other PAHs may be qualitatively
and quantitatively detected using MS (see Section 14.0). This
procedure provides for common GC separation of the PAHs with
-------
T013-37
subsequent detection by either FI or MS (see Figure 12.0). The
following PAHs have been quantified by GC separation with either
FI or MS detection:
Acenaphthene Chrysene
Acenaphthylene Dibenzo(a,h)anthracene
Anthracene Fluoranthene
Benzo(a)anthracene Fluorene
Benzo(a)pyrene Indeno(l,2,3-cd)pyrene
Benzo(b)f1uoranthene Naphthalene
Benzo(e)pyrene Phenanthrene
Benzo(g,h,i)perylene Pyrene
Benzo(k)fluoranthene
The packed column gas chromatographic method described here can not
adequately resolve the following four pairs of compounds: anthra'cene
and phenanthrene; chrysene and benzo(a)anthracene; benzo(b)fluoran-
thene and benzo(k)fluoranthene; and dibenzo(a,h) anthracene and
indeno(l,2,3-cd)pyrene. The use of a capillary column instead of
the packed column, also described in this method, should adequately
resolve these PAHs. However, unless the purpose of the analysis can
be served by reporting a quantitative sum for an unresolved PAH pair,
either capillary gas chromatography/mass spectroscopy (Section 14.0)
or high performance liquid chromatography (Section 15.0) should be
used for these compounds. This section will address the use of
GC/FI detection using packed or capillary columns.
13.2 To achieve maximum sensitivity with the GC/FI method, the extract
must be concentrated to 1.0 ml, if not already concentrated to 1 ml.
If not already concentrated to 1 ml, add a clean boiling chip to the
methylene chloride extract in the concentrator tube. Attach a two-
ball micro-Snyder column. Prewet the micro-Snyder column by adding
about 2.0 mL of methylene chloride to the top. Place the micro K-D
apparatus on a hot water bath (60 to 65°C) so that the concentrator
tube is partially immersed in the hot water. Adjust the vertical
position of the apparatus and the water temperature as required to
complete the concentration in 5 to 10 minutes. At the proper rate
of distillation the balls will actively chatter but the chambers
will not flood. When the apparent volume of liquid reaches 0.5 ml,
remove the K-D apparatus. Drain and cool for at least 10 minutes.
Remove the micro-Snyder column and rinse its lower joint into the
concentrator tube with a small volume of methylene chloride. Adjust
the final volume to 1.0 ml and stopper the concentrator tube.
-------
TO13-38
13.3 Assemble and establish the following operating parameters for
the GC equipped with an FI detector:
Capil lary
(A) (B)
Identification
SPB-5 fused silica
capillary, 0.25 urn
5% phenyl, methyl
siloxane bonded
SPB-5 fused silica
capillary, 0.25 urn
5% phenyl, methyl
siloxane bonded
Packed
Chromosorb W-AW-DMCS
(100/120 mesh) coated
with 3% OV-17
Dimensions
Carrier Gas
Carrier Gas
Flow Rate
Column
Program
Detector
30-m x 0.25-mm ID 30-m x 0.25-mm ID 1.8-m x 2-mm ID
Helium
28-30 cm/sec
( 1 cm/minute)
35°C for 2 min;
program at 8°C/min
to 280°C and hold
for 12 minutes
Heli urn
28-30 cm/sec
( 1 cm/minute)
80°C for 2 min;
program at 8°C/min
to 280°C and hold
for 12 minutes
Nitrogen
30-40 cm/minute
Hold at 100°C for
4 minutes; program at
8°C/min to 280°C and
hold for 15 minutes
Flame lonization Flame lonization Flame lonization
(A) Without column cleanup (see Section 12.4) ~~~~
(B) With column cleanup (see Section 12.4.1)
13.4 Prepare and calibrate the chromatographic system using either
the external standard technique (Section 13.4.1) or the internal
standard technique (Section 13.4.2). Figure 13.0 outlines the
following sequence involving GC calibration and retention time
window determination.
13.4.1 External Standard Calibration Procedure - For each analyte
of interest, including surrogate compounds for spiking, if
used, prepare calibration standards at a minimum of five
concentration levels by adding volumes of one or more stock
standards to a volumetric flask and diluting to volume with
methylene chloride. [Note: All calibration standards of
interest involving selected PAHs, of the same concentration,
can be prepared in the same flask.]
13.4.1.1 Prepare stock standard solutions at a concentration
of 100 ug/uL by dissolving 0.100 gram of assayed PAH
material in methylene chloride and diluting to vol-
in a 10 ml volumetric flask. [Note: Larger volumes
can be used at the convenience of the analyst.]
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T013-39
13.4.1.2 When compound purity is assayed to be 98% or
greater, the weight can be used without correc-
tion to calculate the concentration of the stock
standard. [Note: Commercially prepared stock
standards can be used at any concentration if
they are certified by the manufacturer or by an
independent source.] Transfer the stock standard
solutions into Teflon®-sealed screw-cap bottles.
13.4.1.3 Store at 4°C and protect from light. Stock
standards should be checked frequently for signs
of degradation or evaporation, especially just
prior to preparing calibration standards from
them. Stock standard solutions must be replaced
after one year, or sooner, if comparison with
check standards indicates a problem.
13.4.1.4 Calibration standards at a minimum of five
concentration levels should be prepared through
dilution of the stock standards with methylene
chloride. One of the concentration levels should
be at a concentration near, but above, the method
detection limit. The remaining concentration
levels should correspond to the expected range
of concentrations found in real samples or
should define the working range of the GC.
[Note: Calibration solutions must be replaced
after six months, or sooner, if comparison
with a check standard indicates a problem.]
13.4.1.5 Inject each calibration standard using the
technique that will be used to introduce the
actual samples into the gas chromatograph
(e.g., 1- to 3-uL injections). [Note: The
same amount must be injected each time.]
13.4.1.6 Tabulate peak height or area responses against
the mass injected. The results can be used to
prepare a calibration curve for each analyte.
[Note: Alternatively, for samples that are
introduced into the gas chromatograph using a
syringe, the ratio of the response to the amount
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T013-40
injected, defined as the calibration factor (CF),
can be calculated for each analyte at each stand-
ard concentration by the following equation:
Calibration factor (CF) = Total Area of Peak
Mass injected (in nanograms)
If the percent relative standard deviation
(%RSD) of the calibration factor is less than
20% over the working range, linearity through
the origin can be assumed, and the average
calibration factor can be used in place of a
calibration curve.]
13.4.1.7 The working calibration curve or calibration
factor must be verified on each working day by
the injection of one or more calibration
standards. If the response for any analyte
varies from the predicted response by more
than +20%, a new calibration curve must be
prepared for that analyte. Calculate the
percent variance by the following equation:
Percent variance = R? - RI x 100
Rl
where
Rg = Calibration factor from succeeding analysis.
R! = Calibration factor from first analysis.
13.4.2 Internal Standard Calibration Procedure - To use this
approach, the analyst must select one or more internal
standards that are similar in analytical behavior to the
compounds of interest. The analyst must further demon-
strate that the measurement of the internal standard is
not affected by method or matrix interferences. Due to
these limitations, no internal standard applicable to
all samples can be suggested. [Note: It is recommended
that the internal standard approach be used only when the
GC/MS procedure is employed due to coeluting species.]
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T013-41
13.4.2.1 Prepare calibration standards at a minimum of
five concentration levels for each analyte of
interest by adding volumes of one or more stock
standards to a volumetric flask.
13.4.2.2 To each calibration standard, add a known con-
stant amount of one or more internal standard
and dilute to volume with methylene chloride.
[Note: One of the standards should be at a
concentration near, but above, the method
detection limit. The other concentrations
should correspond to the expected range of
concentrations found in real samples or should
define the working range of the detector.]
13.4.2.3 Inject each calibration standard using the same
introduction technique that will be applied to
the actual samples (e.g., 1- to 3-uL injection).
13.4.2.4 Tabulate the peak height or area responses against
the concentration of each compound and internal
standard.
13.4.2.5 Calculate response factors (RF) for each compound
as follows:
Response Factor (RF) = (AsCis)/(A-jsCs)
where:
As = Response for the analyte to be measured
(area units or peak height).
ATS = Response for the internal standard.
(area units or peak height).
C-jS = Concentration of the internal standard,
(ug/L).
Cs = Concentration of the analyte to be
measured, (ug/L).
13.4.2.6 If the RF value over the working range is con-
stant (<20% RSD), the RF can be assumed to be
invariant, and the average RF can be used for
calculations. [Note: Alternatively, the results
can be used to plot a calibration curve of
response ratios, As/AiS versus RF.]
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T013-42
13.4.2.7 The working calibration curve or RF must be veri-
fied on each working day by the measurement of
one or more calibration standards.
13.4.2.8 If the response for any analyte varies from the
predicted response by more than +20%, a new cali-
bration curve must be prepared for that compound.
13.5 Retention Time Windows Determination
13.5.1 Before analysis can be performed, the retention time windows
must be established for each analyte.
13.5.2 Make sure the GC system is within optimum operating condi-
tions.
13.5.3 Make three injections of the standard containing all
compounds for retention time window determination. [Note:
The retention time window must be established for each
analyte throughout the course of a 72-hr period.]
13.5.4 The retention window is defined as plus or minus three
times the standard deviation of the absolute retention
times for each standard.
13.5.5 Calculate the standard deviation of the three absolute
retention times for each single component standard. In
those cases where the standard deviation for a particular
standard is zero, the laboratory must substitute the
standard deviation of a close eluting, similar compound
to develop a valid retention time window.
13.5.6 The laboratory must calculate retention time windows for each
standard on each GC column and whenever a new GC column
is installed. The data must be noted and retained in a
notebook by the laboratory as part of the user SOP and
as a quality assurance check of the analytical system.
13.6 Sample Analysis
13.6.1 Inject 1- to 3-uL of the methylene chloride extract from
Section 13.2 (however, the same amount each time) using
the splitless injection technique when using capillary
column. [Note: Smaller (1.0 uL) volumes can be injected
if automatic devices are employed.]
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T013-43
13.6.2 Record the volume injected and the resulting peak size
in area units or peak height.
13.6.3 Using either the internal or external calibration pro-
cedure, determine the identity and quantity of each com-
ponent peak in the sample chromatogram through retention
time window and established calibration curve. Table 2
outlines typical retention times for selected PAHs, using
both the packed and capillary column technique coupled
with FI detection, while Figure 14.0 illustrates typical
chromatogram for a packed column analysis.
13.6.3.1 If the responses exceed the linear range of
the system, dilute the extract and reanalyze.
It is recommended that extracts be diluted so
that all peaks are on scale. Overlapping
peaks are not always evident when peaks are off
scale. Computer reproduction of chromatograms,
manipulated to ensure all peaks are on scale
over a 100-fold range, are acceptable if linearity
is demonstrated. Peak height measurements are
recommended over peak area integration when over-
lapping peaks cause errors in area integration.
13.6.3.2 Establish daily retention time windows for each
analyte. Use the absolute retention time for
each analyte from Section 13.5.4 as the midpoint
of the window for that day. The daily retention
time window equals the midpoint j^ three times the
standard deviation determined in Section 13.5.4.
13.6.3.3 Tentative identification of an analyte occurs
when a peak from a sample extract falls within
the daily retention time window. [Note: Con-
firmation may be required on a second GC column,
or by GC/MS (if concentration permits) or by
other recognized confirmation techniques if
overlap of peaks occur.]
13.6.3.4 Validation of GC system qualitative performance
is performed through the use of the midlevel
standards. If the mid-level standard falls out-
side its daily retention time window, the system
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T013-44
is out of control. Determine the cause of the
problem and perform a new calibration sequence
(see Section 13.4).
13.6.3.5 Additional validation of the GC system perform-
ance is determined by the surrogate standard
recovery. If the recovery of the surrogate
standard deviates from 100% by not more than
20%, then the sample extraction, concentration,
clean-up and analysis is certified. If it
exceeds this value, then determine the cause
of the problem and correct.
13.6.4 Determine the concentration of each analyte in the sample
according to Sections 17.1 and 17.2.1.
14. Gas Chromatography with Mass Spectroscopy Detection
14.1 The analysis of the extracted sample for benzo[a]pyrene and other
PAHs is accomplished by an electron impact gas chromatography/mass
spectrometry (El GO/MS) in the selected ion monitoring (SIM) mode
with a total cycle time (including voltage reset time) of one
second or less. The GC is equipped with an ultra No. 2 fused
silica capillary column (50-m x 0.25-mm I.D.) with helium carrier
gas for analyte separation. The GC column is temperature controlled
and interfaced directly to the MS ion source.
14.2 The laboratory must document that the El GC/MS system is properly
maintained through periodic calibration checks. The GC/MS system
should have the following specifications:
Mass range: 35-500 amu
Scan time: 1 sec/scan
GC Column: 50 m x 0.25 mm I.D. (0.25 urn film thickness)
Ultra No. 2 fused silica capillary column or equivalent
Initial column temperature and hold time: 40°C for 4 min
Column temperature program: 40-270°C at 10°C/min
Final column temperature hold: 270°C (until benzo[g,h,i] perylene
has eluted)
Injector temperature: 250-300°C
Transfer line temperature: 250-300°C
Source temperature: According to manufacturer's specifications
Injector: Grob-type, splitless
El Condition: 70 eV
Mass Scan: Follow manufacturer instruction for select ion
monitoring (SIM) mode. ,
Sample volume: 1-3 uL
Carrier gas: Helium at 30 cm/sec.
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T013-45
The GC/MS is tuned using a 50 ng/uL solution of decafluorotriphenyl-
phosphine (DFTPP). The DFTPP permits the user to tune the mass spec-
trometer on a daily basis. If properly tuned, the DFTPP key ions
and ion abundance criteria should be met as outlined in Table 3.
14.3 The GC/MS operating conditions are outlined in Table 4. The
GC/MS system can be calibrated using the external standard tech-
nique (Section 14.3.1) or the internal standard technique
(Section 14.3.2). Figure 15.0 outlines the following sequence
involving the GC/MS calibration.
14.3.1 External standard calibration procedure.
14.3.1.1 Prepare calibration standard of B[a]P or other,
PAHs at a minimum of five concentration levels
by adding volumes of one or more stock standards
to a volumetric flask and diluting to volume
with methylene chloride. The stock standard
solution of B[a]P (1.0 ug/uL) must be prepared
from pure standard materials or purchased as
certified solutions.
14.3.1.2 Place 0.0100 grams of native B[a]P or other PAHs
on a tared aluminum weighing disk and weigh on
a Mettler balance.
14.3.1.3 Quantitatively, transfer to a 10 ml volumetric
flask. Rinse the weighing disk with several
small portions of methylene chloride. Ensure
all material has been transferred.
14.3.1.4 Dilute to mark with methylene chloride.
14.3.1.5 The concentration of the stock standard solution
of B[a]P or other PAHs in the flask is 1.0 ug/uL
[Note: Commerically prepared stock standards may
be used at any concentration if they are certified
by the manufacturer or by an independent source.]
14.3.1.6 Transfer the stock standard solutions into Teflon®-
sealed screw-cap bottles. Store at 4°C and pro-
tect from light. Stock standard solutions should
be checked frequently for signs of degradation or
evaporation, especially just prior to preparing
calibration standards from them.
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T013-46
14.3.1.7 Stock standard solutions must be replaced after
1 yr or sooner if comparison with quality control
check samples indicates a problem.
14.3.1.8 Calibration standards at a minimum of five con-
centration levels should be prepared. [Note:
One of the calibration standards should be at a
concentration near, but above the method detection
limit; the others should correspond to the range
of concenrations found in the sample but should not
exceed the working range of the GC/MS system.]
Accurately pipette 1.0 ml of the stock solution
(1 ug/uL) into another 10 ml volumetric flask,
dilute to mark with methylene chloride. This
daughter solution contains 0.1 ug/uL of B[a]P
or other PAHs.
14.3.1.9 Prepare a set of standard solutions by appropri-
ately diluting, with methylene chloride, accu-
rately measured volumes of the daughter solution
(0.1 ug/uL).
14.3.1.10 Accurately pipette 100 uL, 300 uL, 500 uL, 700 uL
and 1000 uL of the daughter solution (0.1 ug/uL)
into each 10 ml volumetric flask, respectively.
To each of these flasks, add an internal deuterated
standard to give a final concentration of 40
ng/uL of the internal deuterated standard (Section
14.3.2.1). Dilute to mark with methylene chloride.
14.3.1.11 The concentration of B[a]P in each flask is 1 ng/uL,
3 ng/uL, 5 ng/uL, 7 ng/uL, and 10 ug/uL respec-
tively. All standards should be stored at 4°C
and protected from fluorescent light and should
be freshly prepared once a week or sooner if check
standards indicates a problem.
14.3.1.12 Analyze a constant volume (1-3 uL) of each cali-
bration standard and tabulate the area responses
of the primary characteristic ion of each stand-
ard against the mass injected. The results may
be used to prepare a calibration curve for each
compound. Alternatively, if the ratio of response
-------
T013-47
to amount injected (calibration factor) is a
constant over the working range (<20% relative
standard deviation, RSD), linearity through the
origin may be assumed and the average ratio or
calibration factor may be used in place of a
calibration curve.
14.3.1.13 The working calibration curve or calibration
factor must be verified on each working day
by the measurement of one or more calibration
standards. If the response for any parameter
varies from the predicted response by more than
± 20%, the rest must be repeated using a fresh
calibration standard. Alternatively, a new
calibration curve or calibration factor must
be prepared for that compound.
14.3.2 Internal standard calibration procedure.
14.3.2.1 To use this approach, the analyst must select
one or more internal standards that are similar
in analytical behavior to the compounds of inter-
est. For analysis of B[a]P, the analyst should
use perylene -di2. The analyst must further demon-
strate that the measurement of the internal standard
is not affected by method or matrix interferences.
The following internal standards are suggested
at a concentration of 40 ng/uL for specific PAHs:
Perylene -dip Acenaphthene - dm
Benzo(a)pyrene Acenaphthene
Benzo(k)fluoranthene Acenaphthylene
Benzo(g,h,i)perylene Fluorene
Dibenzo(a,h)anthracene
Indeno(l,2,3-cd)pyrene Naphthalene - d«
Chrysene - di? Naphthalene
Benzo(a)anthracene Phenanthrene -dm
Chrysene
Pyrene Anthracene
Fluoranthene
Phenanthrene
14.3.2.2 A mixture of the above deuterated compounds in
the appropriate concentration range are cooer-
cially available (see Section 9.3.1.5).
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T013-48
14.3.2.3 Use the base peak ion as the primary ion for
quantification of the standards. If interferences
are noted, use the next two most intense ions
as the secondary ions. The internal standard
is added to all calibration standards and all
sample extracts analyzed by GC/MS. Retention
time standards, column performance standards,
and a mass spectrometer tuning standard may be
included in the internal standard solution used.
14.3.2.4 Prepare calibration standards at a minimum of
three concentration level for each parameter of
interest by adding appropriate volumes of one
or more stock standards to a volumetric flask.
To each calibration standard or standard mixture,
add a known constant amount of one or more of the
internal deuterated standards to yield a resulting
concentration of 40 ng/uL of internal standard
and dilute to volume with methylene chloride.
One of the calibration standards should be at a
concentration near, but above, the minimum detec-
tion limit (MDL) and the other concentrations
should correspond to the expected range of
concentrations found in real samples or should
define the working range of the GC/MS system.
14.3.2.5 Analyze constant amount (1-3 uL) of each calibra-
tion standard and tabulate the area of the
primary characteristic ion against concentration
for each compound and internal standard, and
calculate the response factor (RF) for each analyte
using the following equation:
RF = (AsCis)/(AisCs)
Where:
As = Area of the characteristic ion for the
analyte to be measured.
A-js = Area of the characteristic ion for the
internal standard.
Cis = Concentration of the internal standard,
(ng/uL).
Cs = Concentration of the analyte to be
measured, (ng/uL).
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T013-49
If the RF value over the working range is a con-
stant (<20% RSD), the RF can be assumed to be'
invariant and the average RF can be used for
calculations. Alternatively, the results can
be used to plot a calibration curve of response
ratios, As/A-js, vs. RF. Table 5.0 outlines key
ions for selected internal deuterated standards.
14.3.2.6 The working calibration curve or RF must be veri-
fied on each working day by the measurement of one
or more calibration standards. If the response
for any parameter varies from the predicted response
by more than _+ 20%, the test must be repeated using
a fresh calibration standard. Alternatively, a
new calibration curve must be prepared.
14.3.2.7 The relative retention times for each compound
in each calibration run should agree within
0.06 relative retention time units.
14.4 Sample Analysis
14.4.1 It is highly recommended that the extract be screened on a
GC/FID or GC/PID using the same type of capillary column
as in the GC/MS procedure. This will minimize contamina-
tion of the GC/MS system from unexpectedly high concentra-
tions of organic compounds.
14.4.2 Analyze the 1 ml extract (see Section 13.2) by GC/MS.
The recommended GC/MS operating conditions to be used
are specified in Section 14.2.
14.4.3 If the response for any quantisation ion exceeds the
initial calibration curve range of the GC/MS system,
extract dilution must take place. Additional internal
standard must be added to the diluted extract to maintain
the required 40 ng/uL of each internal standard in the
extracted volume. The diluted extract must be reanalyzed.
14.4.4 Perform all qualitative and quantitative measurements as
described in Section 14.3. The typical characteristic ions
for selective PAHs are outlined in Table 6.0. Store the
extracts at 4°C, protected from light in screw-cap vials
equipped with unpierced Teflon®-li ned, for future analysis.
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T013-50
14.4.5 For sample analysis, the comparison between the sample and
references spectrum must illustrate:
(1) Relative intensities of major ions in the reference
spectrum (ions >10% of the most abundant ion) should be
present in the sample spectrum.
(2) The relative intensities of the major ions should
agree within +20%. (Example: For an ion with an abundance
of 50% in the standard spectrum, the corresponding sample
ion abundance must be between 30 and 70%).
(3) Molecular ions present in the reference spectrum
should be present in the sample spectrum.
(4) Ions present in the sample spectrum but not in the
reference spectrum should be reviewed for possible back-
ground contaminatiuon or presence of coeluting compounds.
(5) Ions present in the reference spectrum but not in
the sample spectrum should be reviewed for possible sub-
traction from the sample spectrum because of background
contamination or coeluting peaks. Data system library re-
duction programs can sometimes create these discrepancies.
14.4.6 Determine the concentration of each analyte in the sample
according to Sections 17.1 and 17.2.2.
14.5 GC/MS Performance Tests
14.5.1 Daily DFTPP Tuning - At the beginning of each day that
analyses are to be performed, the GC/MS system must be
checked to see that acceptable performance criteria are
achieved when challenged with a 1 uL injection volume
containing 50 ng of decafluorotriphenylphosphine (DFTPP).
The DFTPP key ions and ion abundance criteria that must
be met are illustrated in Table 3.0. Analysis should not
begin until all those criteria are met. Background
subtraction should be staightforward and designed only to
eliminate column bleed or instrument background ions.
The GC/MS tuning standard should also be used to assess
GC column performance and injection port inertness.
Obtain a background correction mass spectra of DFTPP and
check that all key ions criteria are met. If the criteria
are not achieved, the analyst must retune the mass spectrometei
and repeat the test until all criteria are achieved. The
-------
TO13-51
performance criteria must be achieved before any samples,
blanks on standards are analyzed. If any key ion abundance
observed for the daily DFTPP mass tuning check differs by
more than 10% absolute abundance from that observed during
the previous daily tuning, the instrument must be retuned
or the sample and/or calibration solution reanalyzed until
the above condition is met.
14.5.2 Daily 1-point Initial Calibration Check - At the beginning
of each work day, a daily 1-point calibration check is
performed by re-evaluating the midscale calibration
standard. This is the same check that is applied during
the initial calibration, but one instead of five working
standards are evaluated. Analyze the one working standards
under the same conditions the initial calibration curve
was evaluated. Analyze 1 uL of each of the mid-scale
calibration standard and tabulate the area response of
the primary characteristic ion against mass injected.
Calculate the percent difference using the following
equation:
% Difference = RFr - RFT x 100
RFj
Where:
RFj = average response factor from initial cali-
bration using mid-scale standard.
RFC = response factor from current verification check
using mid-scale standard.
If the percent difference for the mid-scale level is
greater than 10%, the laboratory should consider this a
warning limit. If the percent difference for the mid-scale
standard is less than 20%, the initial calibration is
assumed to be valid. If the criterion is not met (<20%
difference), then corrective action MUST be taken. [Note:
Some possible problems are standard mixture degradation,
injection port inlet contamination, contamination at the
front end of the analytical column, and active sites in the
column or chromatographic system.] This check must be met
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T013-52
before analysis begins. If no source of the problem can be
determined after corrective action has been taken, a new
five-point calibration MUST be generated. This criterion
MUST be met before sample analysis begins.
14.5.3 12-hour Calibration Verification - A calibration standard
at mid-level concentration containing B[a]P or other PAHs
must be performed every twelve continuous hours of analysis.
Compare the standard every 12-hours with the average response
factor from the initial calibration. If the % difference
for the response factor (see Section 14.5.2) is less than
20%, then the GC/MS system is operative within initial cali-
bration values. If the criteria is not met (>20% difference),
then the source of the problem must be determined and a new
five-point curve MUST be generated.
14.5.4 Surrogate Recovery - Additional validation of the GC system
performance is determined by the surrogate standard recovery.
If the recovery of the surrogate standard deviates from 100%
by not more than 20%, then the sample extraction, concentra-
tion, clean-up and analysis is certified. If it exceeds this
value, then determine the cause of the problem and correct.
15. High Performance Liquid Chromatography (HPLC) Detection
15.1 Introduction
15.1.1 Detection of B[a]P by HPLC has also been a viable tool in
recent years. The procedure outlined below has been writ-
ten specifically for analysis of B[a]P by HPLC. However, by
optimizing chromatographic conditions [(multiple detector
fluorescence - excitation at 240 nm, emission at 425 nm; ul-
traviolet at 254 nm)] and varying the mobile phase composi-
tion through a gradient program, the following PAHs may
also be quantitatified:
COMPOUND
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo( b ) f 1 uoranthene
Benzo[e]pyrene
Benzo(ghi jperylene
±UV= Ultraviolet
FL= Fluorescences
DETECTOR1
UV
UV
UV
FL
FL
FL
FL
FL
COMPOUND
Benzo(k) f 1 uoranthene
Dibenzo(a,h)anthracene
Fl uoranthene
Fluorene
Indeno(l,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
DETECTOR1
FL
FL
FL
UV
FL
UV
UV
FL
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T013-53
15.1.2 This method provides quantitative identification of the se-
lected PAH's compounds listed above by high performance liquid
chromatography. It is based on separating of compounds of
a liquid mixture through a liquid chromatographic column and
measuring the separated components with suitable detectors.
15.1.3 The method involves solvent exchange, with subsequent HPLC
detection involving ultraviolet (UV) and fluoresence (FL)
detection.
15.2 Solvent Exchange To Acetonitrile
15.2.1 To the extract in the concentrator tube, add 4 ml of ace-
tonitrile and a new boiling chip; attach a micro-snyder
column to the apparatus.
15.2.2 Increase temperature of the hot water bath to 95 to 100°C.
15.2.3 Concentrate the solvent as in Section 12.3.
15.2.4 After cooling, remove the micro-Snyder column and rinse its
lower sections into the concentration tube with approxi-
mately 0.2 mL acetonitrile.
15.2.5 Adjust its volume to 1.0 mL.
15.3 HPLC Assembly
15.3.1 The HPLC system is assembled, as illustrated in Figure 10.
15.3.2 The HPLC system is operated according to the following para-
meters:
HPLC Operating Parameters
Guard Column: VYDAC 201 GCCIOYT
Analytical Column: VYDAC 201 TP5415 C-18 RP (0.46 x 25 cm)
Column Temperature: 27.0 >2°C
Mobile Phase: Solvent Composition Time (Minutes)
40% Acetonitrile/60% water 0
100% Acetonitrile 25
100% Acetonitrile 35
40% Acetonitrile/60% water 45
Linear gradient elution at 1.0 mL/min
Detector: Variable wavelength ultraviolet and fluore-
scence.
Flow Rate: 1.0 mL/minute
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T013-54
[Note: To prevent irreversible absorption due to "dirty"
injections and premature loss of column efficiency, a
guard column is installed between the injector and the
analytical column. The guard column is generally packed
with identical material as is found in the analytical
column. The guard column is generally replaced with a
fresh guard column after several injections ( 50) or
when separation between compounds becomes difficult.
The analytical column specified in this procedure has
been laboratory evaluated. Other analytical columns
may be used as long as they meet procedure and separation
requirements. Table 7.0 outlines other columns uses to
determine PAHs by HPLC.]
15.3.3 The mobile phases are placed in separate HPLC solvent
reservoirs and the pumps are set to yield a total of
1.0 mL/minute and allowed to pump for 20-30 minutes
before the first analysis. The detectors are switched on
at least 30 minutes before the first analysis. UV Detec-
tion at 254 nm is generally preferred. The fluorescence
spectrometer excitation wavelengths range from 250 to 800
nanometers. The excitation and emission slits are both
set at 10 nanometers nominal bandpass.
15.3.4 Before each analysis, the detector baseline is checked
to ensure stable operation.
15.4 HPLC Calibration
15.4.1 Prepare stock standard solutions at PAH concentrations of
1.00 ug/uL by dissolving 0.0100 grams of assayed material in
acetonitrile and diluting to volume in a 10 mL volumetric
flask. [Note: Larger volumes can be used at the convenience
• • -J of the analyst. When compound purity is assayed to be 98%
or greater, the weight can be used without correction to
calculate the concentration of the stock standard.] Commer-
cially prepared stock standards can be used at any concen-
tration if they are certified by the manufacturer or by an
independent source.
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T013-55
15.4.2 Transfer the stock standard solutions into Teflon®-sealed
screw-cap bottles. Store at 4°C and protect from light.
Stock standards should be checked frequently for signs of
degradation or evaporation, especially just prior to pre-
paring calibration standards from them.
15.4.3 Stock standard solutions must be replaced after one year, or
sooner, if comparision with check standards indicates a problem.
15.4.4 Prepare calibration standards at a minimum of five concentra-
tion levels ranging from 1 ng/uL to 10 ng/uL by first diluting
the stock standard 10:1 with acetonitrile, giving a daughter
solution of 0.1 ug/uL. Accurately pipette 100 uL, 300 uL,
500 uL, 700 uL and 1000 uL of the daughter solution (0.1 ug/uL)
into each 10 ml volumetric flask, respectively. Dilute to
mark with acetonitrile. One of the concentration levels
should be at a concentration near, but above, the method
detection limit (MDL). The remaining concentration levels
should correspond to the expected range of concentrations
found in real samples or should define the working range
of the HPLC. [Note: Calibration standards must be replaced
after six months, or sooner, if comparison with check standards
indicates a problem.]
15.4.5 Analyze each calibration standard (at lease five levels)
three times. Tabulate area response vs. mass injected.
All calibration runs are performed as described for sample
analysis in Section 15.5.1. Typical retetion times for
specific PAHs are illustrated in Table 8.0. Linear response
is indicated where a correlation coefficient of at least
0.999 for a linear least-squares fit of the data (concen-
tration versus area response) is obtained. The retention
times for each analyte should agree within +_ 2%.
15.4.6 Once linear response has been documented, an intermediate con-
centration standard near the anticipated levels for each com-
ponent, but at least 10 times the detection limit, should be
chosen for a daily calibration check. The response for the
various components should be within 15% day to day. If greater
variability is observed, recalibration may be required or a
new calibration curve must be developed from fresh standards.
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15.4.7 The response for each component in the daily calibration
standard is used to calculate a response factor according to
the following equation:
RFC = Cr x VT
RC
Where
RFC = response factor (usually area counts) for the
component of interest in nanograms injected/
response unit.
Cc = concentration (mg/L) of analyte in the daily
calibration standard.
Vj = volume (uL) of calibration standard injected.
Rc = response (area counts) for analyte in the cali-
bration standard.
15.5 Sample Analysis
15.5.1 A 100 uL aliquot of the sample is drawn into a clean HPLC
injection syringe. The sample injection loop (10 uL) is
loaded and an injection is made. The data system, if avai-
ble, is activated simultaneously with the injection and the
point of injection is marked on the strip-chart recorded.
15.5.2 After approximately one minute, the injection valve is
returned to the "load" position and the syringe and valve
are flushed with water in preparation for the next sample
analysis.
15.5.3 After elution of the last component of interest, concen-
trations are calculated as described in Section 16.2.3.
[Note: Table 8.0 illustrates typical retention times asso-
ciates with individual PAHs, while Figure 17 represent a
typical chromatogram associates with fluorescence detection.]
15.5.4 After the last compound of interest has eluted, establish
a stable baseline; the system can be now used for further
sample analyses as described above.
15.5.5 If the concentration of analyte exceeds the linear range
of the instrument, the sample should be diluted with mobile
phase, or a smaller volume can be injected into the HPLC.
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15.5.6 Calculate surrogate standard recovery on all samples, blanks
and spikes. Calculate the percent difference by the follow-
ing equation:
% difference = SR- ST x 100
Si
Where
Sj = surrogate injected, ng.
SR = surrogate recovered, ng.
15.5.7 Once a minimum of thirty samples of the same matrix have been
analyzed, calculte the averge percent recovery (%R) and stand-
ard deviation of the percent recovery (SD) for the surrogate.
15.5.8 For a given matrix, calculate the upper and lower control
limit for method performance for the surrogate standard.
This should be done as follows:
Upper Control Limit (UCL) = (%R) + 3(SD)
Lower Control Limit (LCL) = (%R) - 3(SD)
The surrogate recovery must fall within the control limits.
If recovery is not within limits, the following is required.
o Check to be sure there are no errors in calculations
surrogate solutions and internal standards. Also,
check instrument performance.
o Recalculate the data and/or reanalyze the extract if
any of the above checks reveal a problem.
o Reextract and reanalyze the sample if none of the
above are a problem or flag the data as "estimated
concentration."
15.5.9 Determine the concentration of each analyte in the sample
according to Sections 17.1 and 17.2.3.
15.6 HPLC System Performance
15.6.1 The general appearance of the HPLC system should be
similar to that illustrated in Figure 10.
15.6.2 HPLC system efficiency is calculated according to the
following equation:
N * 5.54 t 2
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where:
N = column efficiency (theoretical plates).
tr = retention time (seconds) of analyte.
wl/2 = width of component peak at half height
(seconds).
A column efficiency of >5,000 theoretical plates should
be obtained.
15.6.3 Precision of response for replicate HPLC injections should
be +10% or less, day to day, for analyte calibration stand-
ards at 1 ug/mL or greater levels. At 0.5 ug/mL level and
below, precision of replicate analyses could vary up to 25%.
Precision of retention times should be +2% on a given day.
15.6.4 From the calibration standards, area responses for each
PAH compound can be used against the concentrations to
establish working calibration curves. The calibration
curve must be linear and have a correlation coefficient
greater than 0.98 to be acceptable.
15.6.5 The working calibration curve should be checked daily with
an analysis of one or more calibration standards. If the
observed response (rp) for any PAH varies by more than 15%
from the predicted response (rp), the test method must be
repeated with new calibration standards. Alternately a new
calibration curve must be prepared. [Note: If rn - Pp
>15%, recalibration is necessary.] Pp
15.7 HPLC Method Modification
15.7.1 The HPLC procedure has been automated by Acurex Corpora-
tion as part of their "Standard Operating Procedure for
Polynuclear Aromatic Hydrocarbon Analysis by High Perform-
ance Liquid Chromatography Methods," as reported in Refer-
ence 9 of Section 18.
15.7.2 The system consists of a Spectra Physics 8100 Liquid Chpomat-
ograph, a micro-processor-controlled HPLC, a ternary gradient
generator, and an autosampler (10 uL injection loop).
15.7.3 The chromatographic analysis involves an automated solvent
program allowing unattended instrument operation. The
-------
T013-59
solvent program consists of four timed segments using
varying concentrations of acetonitrile in water with a
constant flow rate, a constant column temperature, and a
10-minute equilibration time, as outlined below.
AUTOMATED HPLC WORKING PARAMETERS
Solvent
Time Composition Temperature Rate
10 minutes 40% Acetonitrile 27.0 +_ 2°C 1 mL/min
equilibration 60% Water
T=0 40% Acetonitrile
60% Water
T=25 100% Acetonitrile
T=35 100% Acetonitrile
T=45 40% Acetonitrile
60% Water
Table 9.0 outlines the associated PAHs with their minimum
detection limits (MDL) which can be detected employing
the automated HPLC methodology.
15.7.4 A Vydac or equivalent analytical column packed with a CIQ
bonded phase is used for PAH separation with a reverse
phase guard column. The optical detection system consists
of a Spectra Physics 8440 variable Ultraviolet (UV)/Visible
(VIS) wavelength detector and a Perkin Elmer LS-4 Fluores-
cence Spectrometer. The UV/VIS detector, controlled by
remote programmed commands, contains a Deuterium lamp with
wavelength selection between 150 and 600 nanometers. It
is set at 254 nanometers with the time constant (detector
response) at 1.0 seconds.
15.7.5 The LS-4 Fluorescence Spectrometer contains separate exci-
tation and emission monochromators which are positioned
by separate microprocessor-controlled stepper motors. It
contains a Xenon discharge lamp, side-on photomultiplier
and a 3-microliter illuminated volume flow cell. It is
equipped with a wavelength programming facility to set
the monochromators automatically to a given wavelength
position. This greatly enhances selectivity by changing
-------
T013-60
the fluorescence excitation and emission detection wave-
lengths during the chromatographic separation in order to
optimize the detection of each PAH. The excitation wave-
lengths range from 230 to 720 nanometers; the emission
wavelengths range from 250 to 800 nanometes. The excita-
tion and emission slits are both set at 10 nanometers
nominal bandpass.
15.7.6 The UV detector is used for determining naphthalene, acenap-
thylene and acenapthene, and the fluorescence detector is
used for the remaining PAHs. Table 9 outlines the detec-
tion techniques and minimum detection limit (MDL) employing
this HPLC system. A Dual Channel Spectra Physics (SP) 4200
computing integrator, with a Labnet power supply, provides
data analysis and a chromatogram. An IBM PC XT with a
10-megabyte hard disk provides data storage and reporting.
Both the SP4200 and the IBM PC XT can control all functions
of the instruments in the series through the Labnet system
except for the LS-4, whose wavelength program is started
with a signal from the High Performance Liquid Chromatograph
autosampler when it injects. All data are transmitted to
the XT and stored on the hard disk. Data files can later
be transmitted to floppy disk storage.
16.0 Quality Assurance/Quality Control
16.1 General System QA/QC
16.1.1 Each laboratory that uses these methods is required to oper-
ate a formal quality control program. The minimum require-
ments of this program consist of an initial demonstration
of laboratory capability and an ongoing analysis of spiked
samples to evaluate and document quality data. The labora-
tory must maintain records to document the quality of the
data generated. Ongoing data quality checks are compared
with established performance criteria to determine if the
results of analyses meet the performance characteristics of
the method. When results of sample spikes indicate a
typical method performance, a quality control check stand-
ard must be analyzed to confirm that the measurements were
performed in an in-control mode of operation.
-------
T013-61
16.1.2 Before processing any samples, the analyst should demon-
strate, through the analysis of a reagent solvent blank,
that interferences from the analytical system, glassware,
and reagents are under control. Each time a set of samples
is extracted or there is a change in reagents, a reagent
solvent blank should be processed as a safeguard against
chronic laboratory contamination. The blank samples should
be carried through all stages of the sample preparation
and measurement steps.
16.1.3 For each analytical batch (up to 20 samples), a reagent
blank, matrix spike and deuterated/surrogate samples must •
be analyzed (the frequency of the spikes may be different
for different monitoring programs). The blank and spiked
samples must be carried through all stages of the sample
preparation and measurement steps.
16.1.4 The experience of the analyst performing gas chromatography
and high performance liquid chromatography is invaluable
to the success of the methods. Each day that analysis is
performed, the daily calibration sample should be evaluated
to determine if the chromatographic system is operating
properly. Questions that should be asked are: Do the
peaks look normal?; Is the response windows obtained
comparable to the response from previous calibrations?
Careful examination of the standard chromatogram can
indicate whether the column is still good, the injector is
leaking, the injector septum needs replacing, etc. If any
changes are made.to the system (e.g., column changed),
recalibration of the system must take place.
16.2 Process, Field, and Solvent Blanks
16.2.1 One cartridge (XAD-2 or PUF) and filter from each batch of
approximately twenty should be analyzed, without shipment
to the field, for the compounds of interest per to serve as
a process blank. A blank level of less than 10 ng per
cartridge/filter assembly for single PAH component is
considered to be acceptable.
-------
TO13-62
16.2.2 During each sampling episode, at least one cartridge and
filter should be shipped to the field and returned, without
drawing air through the sampler, to serve as a field blank.
16.2.3 During the analysis of each batch of samples at least one
solvent process blank (all steps conducted but no cartridge
or filter included) should be carried through the procedure
and analyzed. Blank levels should be less than 10 ng/sample
for single components to be acceptable.
16.2.4 Because the sampling configuration (filter and backup
adsorbent) has been tested for targeted PAHs in the
laboratory in relationship to collection efficiency and
has been demonstrated to be greater than 95% for targeted
PAHs, no field recovery evaluation will occur as part of
the QA/QC program outlined in this section.
16.3 Gas Chromatography with Flame lonization Detection
16.3.1 Under the calibration procedures (internal and external), the
% RSD of the calibration factor should be <20% over the
linear working range of a five point calibration curve
(Sections 13.4.1.6 and 13.4.2.6).
16.3.2 Under the calibration procedures (internal and external),
the daily working calibration curve for each analyte should
not vary from the predicted response by more than +20%
(Sections 13.4.1.7 and 13.4.2.8).
16.3.3 For each analyte, the retention time window must be
established (Section 13.5.1), verified on a daily basis
(Section 13.6.3.2) and established for each analyte
throughout the course of a 72-hour period (Section 13.5.3).
16.3.4 For each analyte, the mid-level standard must fall within the
retention time window on a daily basis as a qualitative
performance evaluation of the GC system (Section 13.6.3.4).
16.3.5 The surrogate standard recovery must not deviate from 100%
by no more than 20% (Section 13.6.3.5).
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16.4 Gas Chromatography with Mass Spectroscopy Detection
16.4.1 Section 14.5.1 requires the mass spectrometer be tuned
daily with DFTPP and meet relative ion abundance require-
ments outlined in Table 3.
16.4.2 Section 14.3.1.1 requires a minimum of five concentration
levels of each analyte (plus deuterated internal standards)
be prepared to establish a calibration factor to illustrate
<20% variance over the linear working range of the
calibration curve.
16.4.3 Section 14.3.1.13 requires the verification of the working
curve each working day (if using the external standard tech-
nique) by the measurement of one or more calibration stand-
ards. The predicted response must not vary by more than
+20%.
16.4.4 Section 14.3.2.6 requires the initial calibration curve
be verified each working day (if using the internal standard
technique) by the measurement of one or more calibration
standards. If the response varies by more than +20% of
predicted response, a fresh calibration curve (five point)
must be established.
16.4.5 Section 14.4.5 requires that for sample analysis, the com-
parison between the sample and reference spectrum illustrate:
(1) Relative intensities of major ions in the reference
spectrum (ions >10% of the most abundant ion) should be
present in the sample spectrum.
(2) The relative intensities of the major ions should
agree within +20%. (Example: For an ion with an abundance
of 50% in the standard spectrum, the corresponding sample
ion abundance must be between 30 and 70%).
(3) Molecular ions present in the reference spectrum
should be present in sample the spectrum.
(4) Ions present in the sample spectrum but not in the
reference spectrum should be reviewed for possible back-
ground contaminatiuon or presence of coeluting compounds.
(5) Ions present in the reference spectrum but not in
the sample spectrum should be reviewed for possible sub-
traction from the sample spectrum because of background
contamination or coeluting peaks. Data system library re-
duction programs can sometimes create these discrepancies.
-------
T013-64
16.4.6 Section 14.5.3 requires that initial calibration curve be
verified every twelve continuous hour of analysis by a
mid-level calibration standard. The response must be
less than 20% difference from the initial response.
16.4.7 The surrogate standard recovery must not deviate from 100%
by no more than 20% (Section 14.5.4).
16.5 High Performance Liquid Chromatography
16.5.1 Section 15.4.4 requires the preparation of calibration
standards at a minimum of five concentration levels to
establish correlation coefficient of at least 0.999 for a
linear least-squares fit of the data.
16.5.2 Section 15.4.5 requires that the retention time for each
analyte should agree within +2%.
16.5.3 A daily calibration check involving an intermediate
standard of the initial five point calibration curve
should be within +15% from day to day.
16.5.4 Section 15.5.6 requires the calculation of percent difference
of surrogate standard recovery in order to establish
control limits:
Upper Control Limit (UCL) = (%R) + 3 (SD)
Lower Control Limit (LCL) = (%R) - 3 (SD)
The surrogate recovery must fall within the control limits.
17. Calculations
17.1 Sample Volume
17.1.1 The total sample volume should be corrected to standard
temperature and pressure.
17.1.2 The total sample volume (Vm) is calculated from the
periodic flow readings (Magnehelic readings taken in
Section 11.3.13) using the following equation.
Vm = Qi + Q? ...On x T
N 1000
Where
Vm = total sample volume (m3) at ambient
conditions .
Ql, Q2-..Qn = flow rates determined at the beginning,
end, and intermediate points during
sampling (m3/minute).
N = number of data points.
T = elapsed sampling time (minutes).
-------
T013-65
17.1.3 The volume of air sampled can be converted to standard
conditions (760 mm Hg pressure and 25°C) using the
following equation:
Vc = Vm x Pfl x 298
Where
760 273 + tA
o
V_ = total sample volume (m) at standard
temperature and pressure (25°C and 760 mm
Hg pressure).
Vm = total sample flow under ambient conditions
(m3).
PA = ambient pressure (mm Hg).
tA = ambient temperature (°C).
17.2 Sample Concentration
17.2.1 6C/FI Detection
17.2.1.1 The concentration of each analyte in the sample
may be determined from the external standard tech-
nique by calculating the amount of standard
injected, from the peak response, using the
calibration curve or the calibration factor
determined in Section 13.4.1.6.
17.2.1.2 The concentration of a specific analyte is
calculated as follows:
Concentration, ng/m3 = C(Aj(Vt)(D)3
Where:
CF = calibration factor for chromatographic
system, peak height or area response
per mass injected, Section 13.4.1.6.
Ax = Response for the analyte in the
sample, area counts or peak height.
Vt = volume of total sample, uL.
D = Dilution factor, if dilution was made
on the sample prior to analysis. If
no dilution was made, D=l, dimensionless.
Vi = volume of sample injected, uL
o
V = total sample volume (m ) at standard
temperature and pressure (25°C and
760 mm Hg), Section 17.1.3.
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T013-66
17.2.2 GC/MS Detection
17.2.2.1 When an analyte has been identified, the quanti-
fication of that analyte will be based on the
integrated abundance from the monitoring of the
primary characteristic ion. Quantification will
take place using the internal standard technique.
The internal standard used shall be the one
nearest the retention time of that of a given
analyte (see Section 14.3.2.1).
17.2.2.2 Calculate the concentration of each identified
analyte in the sample as follows:
Concentration, ng/m3 = [(AV)(IC)(V^.)(D)]
b \ X ' > i 5 n ' t' >u •' J
L(A{S)(RFJ(VI)(VS)]
Where
Ax = area of characteristic ion(s)
for analyte being measured.
Is = amount of internal standard
injected, ng.
Vt - volume of total sample, uL.
D = dilution factor, if dilution was
made on the sample prior to analysis.
If no dilution was made, D = 1,
dimensionless.
AJS = area of characteristic ion(s) for
internal standard.
RF = Response factor for analyte being
measured, Section 14.3.2.5.
Vj = volume of analyte injected, uL.
Vs = total sample volume (m3) at standard
temperature and pressure (25°C and
760 mm Hg), Section 17.1.3.
17.2.3 HPLC Detection
17.2.3.1 The concentration of each analyte in the
sample may be determined from the external
standard technique by calculating response
factor and peak response using the calibration
curve.
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T013-67
17.2.3.2 The concentration of a specific analyte is
calculated as follows:
Concentration, ng/m3 = FfRF )(A
Where
RFC = response factor (nanograms injected
per area counts) calculated in
Section 15.4.7.
Ax » response for the analyte in the sample,
area counts or peak height.
Vt = volume of total sample, uL.
D = dilution factor, if dilution was
made on the sample prior to analysis.
If no dilution was made, D = 1,
dimensionless.
Vi = volume of sample injected, uL.
o
V » total sample volume (nr) at standard
temperature and pressure (25°C and
760 mm Hg), Section 17.1.3.
17.3 Sample Concentration Conversion From ng/m3 to ppbv
17.3.1 The concentrations calculated in Section 17.2 can be
converted to ppbv for general reference.
17.3.2 The analyte concentration can be converted to ppbv using
the following equation:
C« (ppbv) - C« (ng/m3) x 24.4
A A MWA
Where
C« - concentration of analyte, ng/m , calculated
according to Sections 17.2.1 through 17.2.3.
MWA = molecular weight of analyte, g/g-mole
24.4 = molar volume occupied by ideal gas at
standard temperature and pressure (25°C and
760 mm Hg), I/mole.
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18.0 BIBLIOGRAPHY
1. Dubois, L., Zdrojgwski, A., Baker, C., and Monknao J.L., "Some Improve-
ment in the Determination of Benzo[a]Pyrene in Air Samples," Air Pol-
lution Control Association J., 17:818-821, 1967.
2. Intersociety Committee "Tentative Method of Analysis for Polynuclear
Aromantic Hydrocarbon of Atmospheric Particulate Matter, Health Labora-
tory Science, Vol. 7, No. 1, pp. 31-40, January, 1970.
3. Cautreels, W., and Van Cauwenberghe, K., "Experiments on the Distribu-
tion of Organic Pollutants Between Airborne Particulate Matter and
Corresponding Gas Phase", Atmos. Environ., 12:1133-1141 (1978).
4. "Tentative Method of Microanalysis for Benzo[a]Pyrene in Airborne
Particules and Source Effluents," American Public Health Association,
Health Laboratory Science, Vol 7, No. 1, pp. 56-59, January, 1970.
5. "Tentative Method of Chromatographic Analysis for Benzo[a]Pyrene and
Benzo[k]Fluoranthene in Atmospheric Particulate Matter," American
Public Health Association, Health Laboratory Science, Vol. 7, No. 1,
pp. 60-67, January, 1970.
6. "Tentative Method of Spectrophotometric Analysis for Benzo[a]Pyrene
in Atmospheric Particulate Matter," American Public Health Association,
Health Laboratory Science, Vol. 7, No. 1, pp. 68-71, January, 1970.
7. Jones, P.M., Wilkinson, J.E., and Strup, P.E., "Measurement of Poly-
cyclic Organic Materials and Other Hazardous Organic Compounds in
Stack Gases: State-of-art," U.S. EPA-600/2-77-202, 1977.
8. "Standard Operating Procedure for Ultrasonic Extraction and Analysis
of Residual Benzo[a]Pyrene from Hi-Vol Filters via Thin-Layer Chroma-
tography", J.F. Walling, U.S. Environmental Protection Agency, Environ-
mental Monitoring Systems Laboratory, Methods Development and Analysis
Division, Research Triangle Park, N.C., EMSL/RTP-SOP-MDAD-015, December,
1986.
9. "Standard Operating Procedure for Polynuclear Aromantic Hydrocarbon
Analysis by High Performance Liquid Chromatography Methods," Susan Rasor,
Acurex Corporation, Research Triangle Park, N.C., 1978.
10. Rapport, S.W., Wang, Y.Y., Wei, E.T., Sawyer, R., Watkins, B.E., and
Rapport, H., "Isolation and Identification of a Direct-Acting Mutagen
in Diesel Exhaust Particulates", Envir. Sci. Technol., 14:1505-1509,
1980.
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11. Konlg, J., Balfanz, E., Funcke, W., and Romanowski, T., "Determination
of Oxygenated Polycyclic Aromantic Hydorcarbons in Airborne Particu-
late Matter by Capillary Gas Chromatography and Gas Chromatography/Mass
Spectrometry", Anal. Chem., Vol. 55, pp. 599-603, 1983.
12. Chuang, J. C., Bresler,W. E. and Hannan, S. W.."Evaluation of Polyurethane
Foam Cartridges for Measurement of Polynuclear Aromantic Hydrocarbons
in Air," U.S. Environmental Protection Agency, Environmental Monitoring
Systems Laboratory, Methods Development and Analysis Division, Research
Triangle Park, N.C., EPA-600/4-85-055, September, 1985.
13. Chuang, J.C., Hannan, S.W., and Kogtz, J. R., "Stability of Polynuclear
Aromantic Compounds Collected from Air on Quartz Fiber Filters and XAD-2
Resin," U.S. Environmental Protection Agency, Environmental Monitoring
Systems Laboratory, Methods Development and Analysis Division, Research
Triangle Park, N.C., EPA-600/4-86-029, September, 1986.
14. Feng, Y. and Bidleman, T.F., "Influence of Volatility on the Collection
of Polynuclear Aromantic Hydrocarbon Vapors with Polyurethane Foam",
Envir. Sci. Technol., 18:330-333, 1984.
15. Yamasaki, H., Kuwata, K., and Miyamoto, H., "Effects of Ambient Tempera-
ture on Aspects of Airborne Polycyclic Aromantic Hydrocarbons", Envir.
Sci. Technol., Vol. 16, pp. 189-194, 1982.
16. Chuang, J.C., Hannan, S.W. and Kogtz, J. R., "Comparison of Polyurethane
Foam and XAD-2 Resin as Collection Media for Polynuclear Aromantic
Hydrocarbons in Air," U.S. Environmental Protection Agency, Environmental
Monitoring Systems Laboratory, Methods Development and Analysis Division,
Research Triangle Park, N.C., EPA-600/4-86-034, December, 1986.
17. Chuang, J. C., Mack, G. A., Mondron, P. J. and Peterson, B. A., "Evalua-
ation of Sampling and Analyjtical Methodology for Polynuclear Aromatic
Compounds in Indoor Air," Environmental Protection Agency, Environmental,
Monitoring Systems Laboratory, Methods Development and Analysis Division,
Research Triangle Park, N.C., EPA-600/4-85-065, January, 1986.
18. Methods for Organic Chemical Analysis of Municipal and Industrial Waste-
water, U.S. Environmental Protection Agency, Environmental Monitoring
and Support Laboratory, Cincinnati, OH, EPA-600/4-82-057, July 1982.
19. ASTM Annual Book of Standards, Part 31, D 3694. "Standard Practice for
Preparation of Sample Containers and for Preservation," American Society
fdr Testing and Materials, Philadelphia, PA, p. 679, 1980.
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20. Burke, J.A., "Gas Chromatography for Pesticle Residue Analysis; Some
Practical Aspects," Journal of the Association of Official Analytical
Chemists, Vol. 48, p. 1037, 1965.
21. Cole, T., Riggins, R., and Glaser, J., "Evaculation of Method Detection
Limits an Analytical Curve for EPA Merhod 610 - PNAs," International
Symposium on Polynuclear Aromantic Hydrocarbons, 5th, Battelle Columbus
Laboratory, Columbus, Ohio, 1980.
22. "Handbook of Analytical Quality Control in Water and Wastewater Labora-
tories, "U.S. Environmental Protection Agency, Environmental Monitoring
and Support Laboratory, Cincinnati, Ohio 45268, EPA-600/4-79-019, March,
1979.
23. ASTM Annual Book of Standards, Part 31, D 3370, "Standard Practice for
Sampling Water," American Society for Testing and Materials, Philadelphia
PA, p. 76, 1980.
24. Protocol for the Collection and Analysis of Volatile POHC's (Principal
Organic Hazardous Constituents) using VOST (Volatile Organic Sampling
Train), PB84-170042, EPA-600/8-84-007, March, 1984.
25. Sampling and Analysis Methods for Hazardous Waste Combustion - Methods
3500, 3540, 3610, 3630, 8100, 8270, and 8310; Test Methods For Evaluating
Solid Waste (SW-846), U.S. EPA, Office of Solid Waste, Washington, D.C.
26. Chuang, C.C. and Peterson, B.A., "Review of Sampling and Analysis Method-
ology for Polunuclear Aromantic Compounds in Air from Mobile Sources",
Final Report, EPA-600/S4-85-045, August, 1985.
27. "Measurement of Polycyclic Organic Matter for Environmental Assessment,"
U.S. Environmental Protection Agency, Industrial Environmental Research
Laboratory, Research Triangle Park, N.C., EPA-600/7-79-191, August, 1979.
28. "Standard Operating Procedure No. FA 113C: Monitoring For Particulate
and Vapor Phase Pollutants Using the Portable Particulate/Vapor Air
Sampler," J.L. Hudson, U.S. Environmental Protection Agency, Region VII,
Environmental Monitoring and Compliance Branch, Environmental Services
Division, Kansas City, Kansas, March, 1987.
29. Technical Assistance Document for Sampling and Analysis of Toxic Organic
Compounds in Ambient Air, U.S. Environmental Protection Agency, Environ-
mental Monitoring Systems Laboratory, Quality Assurance Division,
Research Triangle Park, N.C., EPA-600/4-83-027, June, 1983.
-------
T013-71
30. Winberry, W. T., Murphy, N.T., Supplement to Compendium of Methods
for the Determination of Toxic Organic Compounds in Ambient Air,
U.S. Environmental Protection Agency, Environmental Monitoring Systems
Laboratory, Quality Assurance Division, Research Triangle Park, N.C.,
EPA-600/4-87-006, September, 1986.
31. Riggins, R. M., Compendium of Methods for the Determination of Toxic
Organic Compounds in Ambient Air, U.S. Environmental Protection
Agency, Environmental Monitoring Systems Laboratory, Quality Assurance
Division Research Triangle Park, N.C., EPA-600/4-84-041, April, 1984.
32. Quality Assurance Handbook for Air Pollution Measurement Systems, Vo-
lume II - "Ambient Air Specific Methods," Section 2.2 - "Reference
Method for the Determination of Suspended Particulates in the Atmos-
phere," Revision 1, July, 1979, EPA-600/4-77-027A.
33. ASTM Annual Book of Standards, Part 31, D 3694. "Standard Practice
for Preparation of Sample Containers and for Preservation," American
Society for Testing and Materials, Philadelphia, PA, p. 679, 1980. '
34. "HPLC Troubleshooting Guide - How to Identify, Isolate, and Correct '*
Many HPLC Problems," Supelco, Inc., Supelco Park, Bellefonte, PA,
16823-0048, Guide 826, 1986.
35. "Carcinogens - Working With Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, August, 1977.
36. "OSHA Safety and Health Standards, General Industry," (29CFR1910),
Occupational Safety and Health Administration, OSHA 2206, Revised,
January, 1976.
37. "Safety in Academic Chemistry Laboratories,'1 American Chemical Society
Publication, Committee on Chemical Safety, 3rd Edition, 1979.
38. Hudson, J., "Monitoring for Particulate And Vapor Phase Pollutants
Using A Portable Particulate/Vapor Air Sampler - Standard Operating
Procedure No. SA-113-C", U.S. Environmental Protection Agency, Region
VII, Environmental Services Division, 25 Funston Road, Kansas City,
Kansas, 66115.
-------
T013-72
TABLE 1.0 FORMULAE AND PHYSICAL PROPERTIES OF SELECTIVE PAHs
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b) f 1 uoranthene
Benzo(e)pyrene
Benzo(g.h,i)perlene
Benzo(k)fl uoranthene
Chrysene
Dibenzo(a,h)anthracene
Fl uoranthene
Fluorene
Indeno(l,2,3-cd)pyrene
^Naphthalene
Phenanthrene
Pyrene
FORMULA
C12H10
C12H8
Ci4Hio
C18H12
C20H12
C20H12
C2QH12
C22H12
C20Hi2
Cl8Hl2
C£2Hi4
c^io
Cl3HlO
C22H12
ClOHs
Ci4Hio
CieHio
MOLECULAR
WEIGHT
154.21
152.20
178.22
228.29
252.32
252.32
252.32
276.34
252.32
228.29
278.35
202.26
166.22
276.34
128.16
178.22
202.26
MELTING POINT
°C
96.2°
92-93
218°
158-159
177°
168
178-179
273
217
255-256
262
110
116-117
161.5-163
80.2
100°
156
BOILING POINT
°C
279
265-275
342
-
310-312
_
-
480
-
-
-
293-295
-
217.9
340
399
CASE
#
83-32-9
208-96-8
120-12-7
56-55-3
50-32-8
205-99-2
192-92-2
191-24-2
207-08-9
218-01-9
53-70-3
206-44-0
86-73-7
193-39-5
91-20-3
85-01-8
129-00-0
*Many of these compounds sublime.
recycled paper
ecology and environment
-------
T013-73
TABLE 2.0 RETENTION TIMES FOR SELECTIVE PAHs FOR PACKED
AND CAPILLARY COLUMNS
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo( a, h) anthracene
Fluoranthene
Fluorene
Indeno(l,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
10.8
1 f\ A
10.4
1C f\
15,9
20.6
29.4
28.0
38.6
28.0
f\ A T
24.7
36.2
19.8
12.6
36.2
4.5
1C rt
15.9
20.6
Packed1 Capillary2
16.8
15.9
20.7
29.1
36.2
34.2
48.4
34.4
29.3
46.1
24.3
18.1
45.6
11.0
20.6
25.0
conditions: Chromosorb W-AW-DMCS (100/120 mesh) coated with 3%
OV-17, packed in a 1.8-m long x 2 mm ID glass column, with nitrogen
carrier gas at a flow rate of 40 mL/min. Column temperature was held
at 100°C for 4 min. then programmed at 8°/minute to a final hold at 280 C.
2Capillary GC conditions: 30 meter fused silica SPB-5 capillary column;
flame ionization detector, splitless injection; oven temperature held at
80 Segree C for 2 minutes, increased at 8 degrees/min. to 280 degrees C.
-------
T013-74
TABLE 3.0 DFTPP KEY IONS AND ION ABUNDANCE CRITERIA
Mass
68
70
127
197
198
199
275
365
441
442
443
Ion Abundance Criteria
—• —-—
30-60% of mass 198
Less than 2% of mass 69
Less than 2% of mass 69
40-60% of mass 198
Less than 1% of mass 198
Base peak, 100% relative abundance
5-9% of mass 198
10-30% of mass 198
Greater than 1% of mass 198
Present but less than mass 443
Greater than 40% of mass 198
17-23% of mass 442
-------
T013-75
TABLE 4.0 GC AND MS OPERATING CONDITIONS
Chromatography
folumn Hewlett-Packard Ultra #2 crossi inked 5% phenyl
° methyl silicone (50 m x 0.25 mm, 0.25 urn film
thickness) or equivalent
Carrier Gas Helium velocity 20 cm3/sec at 250°C
Injection Volume Constant (1-3 uL)
Injection Mode Splitless
Temperature Program
Initial Column Temperature 45°C
i^to 100°C in 5 rcin, then 100°C to 320«C at
8°C/min
Final Hold Time 15 min
Mass Spectrometer
Detection Mode Multiple ion detection, SIM mode
-------
T013-76
j-naphthalene
Dio-phenanthrene
Phenathrene
Anthracene
Fluoranthene
D10-Pyrene
Pyrene
Cyclopenta[c,d]pyrene
Benz[a]anthracene
Di2-chrysene
Benzo[e]pyrene
Di2-benzo[a]pyrene
Benzo[a]pyrene
136
188
178
178
202
212
202
226
228
240
252
264
252
-------
T013-77
TABLE 6.0 CHARACTERISTIC IONS FROM GC/MS DETECTION
FOR SELECTED PAHs
Primary
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Fluorene
Indeno(l,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
154
152
178
228
252
252
276
252
228
278
202
166
276
128
178
202
153
151
179
229
253
253
138
253
226
139
101
165
138
129
179
200
Secondajx
152
153
176
226
125
125
277
125
229
279
203
167
227
127
176
203
-------
T013-78
TABLE 7.0. COMMERCIAL AVAILABLE COLUMNS FOR PAH
ANALYSIS USING HPLC
Company
Column Identification
Column Name
The Separation Group
P.O. Box 867
Hesperia, California 92345
Rainin Instrument Company
Mack Road
Wasurn, MA 01801-4626
Supelco, Inc.
Supelco Park
Bellefonte, PA 16823-0048
DuPont Company
Biotechnology Systems
Barley Mill Plaza, P24
Wilmington, DE 19898
Perkin-Elmer Corp.
Corporate Office
Main Avenue
Norwalk, CT 06856
Waters Associates
34-T Maple St.
Mil ford, MA 01757
201-TP
Ultrasphere - ODS
LC-PAH
ODS
VYDAC
ALEX
Supelcosil
Zorbax
HC-ODS
u-Bondapak
Sil-X
NH3 u-Bondapak
-------
T013-79
TABLE 8.0. TYPICAL RETENTION TIME FOR SELECTIVE PAHs
BY HPLC SEPARATION AND DETECTION
. — ' •
Compound
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
tenzo(a)pyrene
Benzo(b)fluoranthene
3enzo(e)pyrene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Fluorene
Indeno(l,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
__ — • !
— —
Retention Times (minutes)
HPLC Conditions
Condition A
Fluorescence UV
— ' — • —
20 5
tw • */
18 5
•LV-' • v
00 A
£J.£T
oo c
28.5
OO Q
oo.y
31.6
36.3
32.9
9Q "?
U3 . *^
35.7
*)A C
£H.3
21.2
37.4
16 6
xu . u
OO 1
C.C.,1
05 4
C.
-------
T013-80
TABLE 9.0.
RETENTION TIMES (RT) AND MINIMUM DETECTION LIMITS (MDLs) FOR
SELECTED PAHs USING ULTRAVIOLET AND FLOURESCENCE DETECTION
PAH
Ultraviolet Detector
RT MDL
RT = Retention time in minutes
MDL = Minimum detection limit
Flourescence Detector
RT MDL
Naphthalene
Acenaphthylene
Acenaphthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzo(a)anthracene
Chrysene
Benzo(b)fluoranthene
Benzo{k)fluoranthene
Benzo(a)pyrene
Dibenzo(a,h)anthracene
Benzo(ghi)perylene
Indeno(1.2,3-cd)Dvrene
14.0
15.85
18.0
18.5
19.9
21.0
22.5
23.4
26.3
26.7
29.3
30.2
31.1
32.7
33.9
34.6
250pg/uL
250pg/uL
250pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
50pg/uL
18.5
19.9
21.0
22.5
23.4
26.3
26.7
29.3
30.2
31.1
32.7
33.9
34.6
5pg/uL
lOpg/uL
50pg/uL
lOpg/uL
5pg/uL
5pg/uL
5pg/uL
lOpg/uL
5pg/uL
5pg/uL
5pg/uL
5pg/uL
50pg/uL
-------
TO13-81
Acenaphthene
Benzo(a)anthracene
Benzo(g,h,!)perylene
Chrysene
Fluorene
Acenaphthylene
Benzo(b)fluoranthene
Benzo(a)pyrene
Dibenz(a,h)anthracene
lndeno(1,2,3-c,d)pyrene
Anthracene
Benzo(k)fluoranthene
Benzo(e)pyrene
Fluoranthene
Naphthalene
Phenanthrene Pyrene
FIGURE 1.0 RING STRUCTURE OF SELECTIVE PAHs.
-------
TO 13-82
Filter Retaining Ring
Silicone Gasket
Air Flow
4" Diameter
Pallflex Filter
Particulate
Filter
Support
Adsorbent
Cartridge and
Support
Air Flow
Exhaust
4" Diameter
-Pallflex
Filter
TX40H120WW
Filter Support Screen
Filter Support Base
Silicone Gasket
Glass Cartridge
Adsorbent
(XAD-2 or PUF)
Retaining Screen
Silicone Gasket
Adsorbent
Support
FIGURE 2.0 GENERAL METAL WORKS SAMPLING HEAD
-------
T013-83
Water In-
Soxhlet
Extraction.
Tube and
Thimble
$>-*• Water Out
Alllhn
Condenser
•Flask
(a) Soxhlet Extraction Apparatus
with AHihn Condenser
3 Ball Macro
Synder Column
500 mL
Evaporator
Flask
10 mL
Concentrator
Tube
(b) Kudema-Danish (K-D) Evaporator
with Macro Synder Column
Disposable 6 inch
Pasteur Pipette
-1 Gram Sodium Sulfate
JO Gram Silica
~Gel Slurry
-—Glass Wool Plug
(c) Silica Gel Clean-up Column
FIGURE 3. APPARATUS USES IN SAMPLING ANALYSIS.
-------
1ttaiuuo,nAira pus A'
TO13-84
Sampling
Head
(See Figure 2)
Magnehelic
Gauge
0-100 In.
Elapsed Time
Meter
Exhaust
Duct
(6 In. x 10 ft)
Base Plate
FIGURE 4. MODIFIED HIGH VOLUME AIR SAMPLER
GENERAL METAL WORKS MODEL PS-1 SAMPLER
-------
TO13-85
Exhaust Hose
4" Diameter Pullflex
Filter And Support
XAD-2 or PUF Adsorbent
Cartridge And Support
Quick Release Connections
For Module
Quick Release Connections
For Magnahelic Gage
Flow Control Valve
Elapsed Time Indicator
FIGURE 5. PORTABLE HIGH VOLUME AIR SAMPLER
-------
TO13-86
Mercury
Manometer
Orifice
Barometer
Thermometer
Filter Adapter
Rootsmeter
High Volume Motor
Resistance Plates
FIGURE 6. LABORATORY ORIFICE CALIBRATION SETUP
-------
'1
PI
JC.
Orifice No..
K
.mmHg
Roots Meter No..
Name.
Date-
Resistance
Plates
(No. of Holes)
5
7
10
13
18
Air Volume
Measured By
Rootsmeter
Vm
(ft3)
200
200
300
300
300
(m3)
5.66
5.66
8.50
8.50
8.50
Standard
Volume
VSW
(std m3)
Time For Air
Volume To
Pass Through
Rootsmeter
0
(min)
Roots Meter
Pressure
Differential
AP
(mm Hg)
Pressure
Drop Across
Orifice
AH
(in.H2O)
x-Axis
Standard
Flow Rate
Qstd
(std m3/min)
y-Axis
VAH(P1/Psfd)(298/T1)
Value
GO
OO
Factors: (ft3) 0.02832
~\ = m3and(in.Hg)25.4(^^.J = mmHg.
ft3; \,in-H9/
Calculation Equations:
Pstd
Where:
Tsfd = 298 K
PsW = 760.0 mmHg
2.
.VsW
• HBHBW^H
e
FIGURE 7. ORIFICE CALIBRATION DATA SHEET.
-------
T013-88
' | ' I I I | I I I I | I I I I
I I I I i i i I I I i i i I . i i , I i ,,,
0.0 0.25 0.50 0.75 1.00 1.25 1.50
FIGURE 8. ORIFICE METER CALIBRATION CURVE
-------
Performed by.
Date/Time
Calibration Orifice.
Manometer S/N_
.S/N.
Ambient Temperature.
Bar. Press. _____
.mrnHg
Sampler
S/N
Varlac
Setting V
Timer OK?
Yes/No
•———-————
Flow Rate Transfer Standard
Manometer
(n.H2O
Q a
std
Sampler Venturl Date
Magnehellc,
laH2O
Om,"
Comments
00
\o
* From Calibration Curve For Flow Rate Transfer Standard (Section 11.2.1).
b From Calibration Curve tor Venturl Tube Using Flow Rate Transfer Standard (Section 11.2A9).
FIGURE 9. FIELD CALIBRATION DATA SHEET
-------
Sampler Site
Before
After
Sampler Location.
Date •
Barometric Pressure
Ambient Temperature.
Site.
Date.
Performed By.
Sampler
S/N
Sampling
Location
I.D.
Height
Above
Ground
Identification
No.
Rlter
XAD-2
or PUF
Sampling Period
Start
Stop
Totaling
Sampling
Time, min.
Pump Timer
Hr. Min.
Sampler Flow Check1
Manometer A H,
Inches of Water
QXS
M
Qms
Within
± 10%
o
I—>
£
o
1
Must Be Performed Before and After Each Sampling Period
Checked By.
Date
FIGURE 10. FIELD TEST DATA SHEET.
-------
T013-91
Adsorbent
PUForXAD-2)
Surrogate Standard
Addition for GC/FID
and GC/MS Analysis
(Section 12.2.1)
I
Soxhlet Extraction In Methylene Chloride
18 Hours/3 Cycles/Hr) or
Ether/Hexane Solvent
(Section 12.2.1)
Drying with Anhydrous Sodium Sulfate
(Section 12.2.2)
Kuderna-Danish (K-D) Evaporator
Attached with Macro Synder Column
(Section 12.2.3)
Surrogate Standard
Addition for
HPLC Analysis
(Section 12.2.1)
Water Bath
at60°C
Solvent Exchange to Cyclohexane by
K-D Apparatus with Macro Snyder Column
(Section 12.3.2)
Add 5 mL of
Cyclohexane
r
(No Extract Clean-up Required) Concentrate
toLOmL
4j —
1 (Extract Clean-Up
y Required)
f —
Pentane
Fraction
(Optional)
Silica Gel Column Topped with
Sodium Sulfate
(Section 12.4.1)
or Lobar Column
(Section (12.4.2)
f
If
Methylene Chloride/Pentane Fraction
Concentrated by K-D Apparatus to 1 mL
(Section 12.4.1 .3)
»J
—
Add 0.5 mL
Cyclohexane
Pentane
Elution
Methylene
Chloride/Pentane
Elution
Methanol
Elution
T
Methanol
Fraction
(Optional)
Analysis by
GC or HPLC
J_
Gas Chromatography
Analysis
(Section 13.0)
Flame lonization
(Fl) Detection
(Section 13.3)
Solvent Exchange to Acetonitrile
by K-D Apparatus
(Section 15.2)
Mass
Spectroscopy
(MS) Detection
(Section 14.0)
HPLC Analysis
(Section 15.4)
Ultra Violet
(UV) Detection
Fluorescence
(FL) Detection
FIGURE 11.0. SAMPLE CLEAN-UP, CONCENTRATION,
SEPARATION AND ANALYSIS SEQUENCE.
-------
TO13-92
Injection
Port
mm.
GC Column
(Capillary
or Packed)
Flame
lonization
(Fl)
Detector
Mass
Spectroscopy
(MS)
In
SCAN Mode
Flow
Controller
Carrier
Gas
Bottle
FIGURE 12.0
GC SEPARATION WITH SUBSEQUENT
FLAME IONIZATION (Fl) OR MASS
SPECTROSCOPY (MS) DETECTION.
-------
TO13-93
I
Select Internal Standards
Having Similar Behavior to ^
Compounds of Interest
(Section 13.4.2)
I
Prepare Calibration/
Internal Standards
(Section 13.4.2.1)
4
Inject Calibration Standards:
Calculate Response Factor (RF)
(Section 13.4.2.2)
4
Verify Working Calibration
Curve or RF Each Day —
(Section 13.4.2.6)
Establish Gas Chromatograph
Operating Parameters:
(Section 13.3)
Prepare Calibration Standards
(Section 13.4)
Tternal Standard ^ External Stand
Calibration Technique
• (Section 13.4)
Calculate Retention
(Section 13.5)
i^
|
Introduce Extract Into
Gas Chromatograph by
Direct Injection
(Section 13.6.1)
\ r
Does Response Exceed
Linear Range
of System?
(Section 13.6.3.1)
^
Determine Identity and
Quantity of Each Analyte,
Using Appropriate Formulas
and Curves
(Section 13.6.3 and 17.2.1)
ard 1
Prepare Calibration Standards
^ for Each Analyte
of Interest
(Section 13.4.1)
^
Inject Calibration Standard:
Prepare Calibration Curve
or Calibration Factor (CF)
(Section 13.4.1.5)
1 '
Verify Working Calibration
Curve Each Day
(Section 13.4.1.7)
yes Dilute Extract
(Section 13.6.3.1)
FIGURE 13.0 GC CALIBRATION AND RETENTION
TIME WINDOW DETERMINATION.
-------
TO13-94
t
8
40
Retention Time, minutes
Column: 3% OV-17 on Chromosorb W-AW-DCMS
Program: 100 °C. 4 min., 8 ° per min. to 280 °C.
Detector: Flame lonlzation
FIGURE 14.0 TYPICAL CHROMATOGRAM OF SELECTIVE PNAs
BY GC EQUIPPED WITH Fl DETECTOR.
-------
1013-95
Establish Gas Chromatograph/
Mass Spectroscopy Operating Parameters:
Prepare Calibration Standards
(Section 14.2)
Select Internal Standards
Having Similar Behavior to
Compounds of Interest
Normally Deuterated PAHs
(Section 14.3.2 and 14.3.2.1)
Tune GC/MS with DFTPP
(Section 14.2)
Internal Standard
•4—
Calibration Technique
(Section 14.3)
External Standard
—*
Prepare Calibration Standards
for Each Analysis
of Interest
(Section 14.3.1)
Prepare Calibration
Standards
(Section 14.3.2.4.1)
Add Internal
Standards
(Section 14.3.1.10)
Inject Calibration Standards:
Calculate Response Factor (RD)
(Section 14.3.2.5)
Verify Working Calibration
Curve or RF Each Day
(Section 14.3.2.6)
Introduce Extract into
GC/MS by Direct Injection
(Section 14.4)
Does Response Exceed
Linear Range of System?
(Section 14.4.3)
Inject Calibration Standard:
Prepare Calibration Curve
or Calibration Factor (CF)
(Section 14.3.1 .12)
Verify Working Calibration
Curve Each Day
(Section 14.3.1 .13)
Yes
Dilute Extract and
Reanalyze
(Section 14.4.3)
Calculate Concentration of
Each Analyte, Using
Appropriate Formulas
(Section 14.4.4 and 17.2.2)
Daily GC/MS Tuning
With DFTPP
(Section 14.5.1)
fe-
GC/MS Performance Test
(Section 14.5)
-^
12-Hr Calibration Verification
(Section 14.5.3)
Daily 1-Point
Calibration Verification
(Section 14.5.2)
FIGURE 15.0 GC/MS CALIBRATION AND ANALYSIS.
-------
Guard Analytical
Column Column
Helium
nitrite Reservoir Water Reservoir High
with Fitter \ with Filter Pump
Variable
Wavelength
UV/Fluorescence
Detector
Data System
and Recorder
o
I—"
V
Binary
Proportioning
Valve
FIGURE 16. IMPORTANT COMPONENTS OF AN HPLC SYSTEM.
-------
METHOD T014
DETERMINATION OF VOLATILE ORGANIC COMPOUNDS (VOCs) IN AMBIENT AIR
USING SUMMA® PASSIVATED CANISTER SAMPLING AND GAS
CHROMATOGRAPHIC ANALYSIS
1. Scope
1.1 This document describes a procedure for sampling and analysis
of volatile organic compounds (VOCs) in ambient air. The method
is based on collection of whole air samples in SUMMA® passivated
stainless steel canisters. The VOCs are subsequently separated
by gas chromatography and measured by mass-selective detector or
multidetector techniques. This method presents procedures for
sampling into canisters to final pressures both above and below
atmospheric pressure (respectively referred to as pressurized
and subatmospheric pressure sampling).
1.2 This method is applicable to specific VOCs that have been tested
and determined to be stable when stored in pressurized and sub-
atmospheric pressure canisters. Numerous compounds, many of
which are chlorinated VOCs, have been successfully tested for
storage stability in pressurized canisters (1,2). However,
minimal documentation is currently available demonstrating
stability of VOCs in subatmospheric pressure canisters.
1.3 The organic compounds that have been successfully collected in
pressurized canisters by this method are listed in Table 1.
These compounds have been successfully measured at the parts per
billion by volume (ppbv) level.
2. Applicable Documents
2.1 ASTM Standards
D1356 - Definition of Terms Related to Atmospheric Sampling and
Analysis „.',,. u
E260 - Recommended Practice for General Gas Chromatography
Procedures .
E355 - Practice for Gas Chromatography Terms and Relationships
2.2 Other Documents
U.S. Environmental Protection Agency Technical Assistance Document (3)
Laboratory and Ambient Air Studies (4-17)
-------
Revision 1.0
June, 1988
METHOD T014
DETERMINATION OF VOLATILE ORGANIC COMPOUNDS (VOCs) IN AMBIENT AIR
USING SUMMA® PASSIVATED CANISTER SAMPLING AND GAS CHROMATOGRAPHIC ANALYSIS
OUTLINE
1. Scope
2. Applicable Documents
3. Summary of Method
4. Significance
5. Definitions
6. Interferences and Limitations
7. Apparatus
7.1 Sample Collection
7.1.1 Subatmospheric Pressure
7.1.2 Pressurized
7.2 Sample Analysis
7.2.1 GC-MS-SCAN Analytical System
7.2.2 GC-MS-SIM Analytical System
7.2.3 GC-Multidetector Analytical System
7.3 Canister Cleaning System
7.4 Calibration System and Manifold
8. Reagents and Materials
9. Sampling System
9.1 System Description
9.1.1 Subatmospheric Pressure Sampling
9.1.2 Pressurized Sampling
9.1.3 All Samplers
9.2 Sampling Procedure
10. Analytical System
10.1 System Description
10.1.1 GC-MS-SCAN System
10.1.2 GC-MS-SIM System
10.1.3 GC-Multidetector (GC-FID-ECD-PID) System
10.2 GC-MS-SCAN-SIM System Performance Criteria
10.2.1 GC-MS System Operation
10.2.2 Daily GC-MS Tuning
10.2.3 GC-MS Calibration
10.2.3.1 Initial Calibration
10.2.3.2 Routine Calibration
10.3 GC-FID-ECD System Performance Criteria (With Optional PID)
10.3.1 Humid Zero Air Certification
10.3.2 GC Retention Time Windows Determination
10.3.3 GC Calibration
10.3.3.1 Initial Calibration
10.3.3.2 Routine Calibration
10.3.4 GC-FID-ECD-PID System Performance Criteria
10.4 Analytical Procedures
10.4.1 Canister Receipt
10.4.2 GC-MS-SCAN Analysis (With Optional FID System)
10.4.3 GC-MS-SIM Analysis (With Optional FID System)
10.4.4 GC-FID-ECD Analysis (With Optional PID System)
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OUTLINE (Cont.)
11. Cleaning and Certification Program
11.1 Canister Cleaning and Certification
11.2 Sampling System Cleaning and Certification
11.2.1 Cleaning Sampling System Components
11.2.2 Humid Zero Air Certification
11.2.3 Sampler System Certification With Humid
Calibration Gas Standards
12. Performance Criteria and Quality Assurance
12.1 Standard Operating Procedures (SOPs)
12.2 Method Relative Accuracy and Linearity
12.3 Method Modification
12.3.1 Sampling
12.3.2 Analysis
12.4 Method Safety
12.5 Quality Assurance
12.5.1 Sampling System
12.5.2 GC-MS-SCAN-SIM System Performance Criteria
12.5.3 GC-Multidetector System Performance Criteria
13. Acknowledgements
14. References
APPENDIX A - Availability of Audit Cylinders from U.S. Environmental
Protection Agency (USEPA) to USEPA Program/Regional Offices,
State/Local Agencies and Their Contractors
APPENDIX B - Operating Procedures for a Portable Gas Chromatograph Equipped
With a Photoionization Detector
APPENDIX C - Installation and Operating Procedures for Alternative Air Toxics
Samplers
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Summary of Method
3.1 Both subatmospheric pressure and pressurized sampling modes use
an initially evacuated canister and a pump-ventilated sample line
during sample collection. Pressurized sampling requires an addi-
tional pump to provide positive pressure to the sample canister.
A sample of ambient air is drawn through a sampling train comprised
of components that regulate the rate and duration of sampling into
a pre-evacuated SUMMA® passivated canister.
3.2 After the air sample is collected, the canister valve is closed,
an identification tag is attached to the canister, and the canis-
ter is transported to a predetermined laboratory for analysis.
3.3 Upon receipt at the laboratory, the canister tag data is recorded
and the canister is attached to the analytical system. During analy-
sis, water vapor is reduced in the gas stream by a Nafion® dryer
(if applicable), and the VOCs are then concentrated by collection
in a cryogenically-cooled trap. The cryogen is then removed and the
temperature of the trap is raised. The VOCs originally collected
In the trap are revolatilized, separated on a GC column, then de-
tected by one or more detectors for identification and quantitation.
3.4 The analytical strategy for Method T014 involves using a high-
resolution gas chromatograph (GC) coupled to one or more appro-
priate GC detectors. Historically, detectors for a GC have been
divided into two groups: non-specific detectors and specific
detectors. The non-specific detectors include, but are not limited
to, the nitrogen-phosphorus detector (NPD), the flame ionization
detector (FID), the electron capture detector (ECD) and the photo-
ionization detector (PID). The specific detectors include the
mass spectrometer (MS) operating in either the selected ion moni-
toring (SIM) mode or the SCAN mode, or the ion trap detector.
The use of these detectors or a combination of these detectors
as part of an analytical scheme is determined by the required
specificity and sensitivity of the application. While the non-
specific detectors are less expensive per analysis and in some
cases more sensitive than the specific detector, they vary in
- specificity and sensitivity for a specific class of compounds.
For instance, if multiple halogenated compounds are targeted,
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T014-3
an ECD is usually chosen; if only compounds containing nitrogen
or phosphorus are of interest, a NPD can be used; or, if a variety
of hydrocarbon compounds are sought, the broad response of the
FID or PID is appropriate. In each of these cases, however, the
specific identification of the compound within the class is deter-
mined only by its retention time, which can be subject to shifts
or to interference from other nontargeted compounds. When misiden-
tification occurs, the error is generally a result of a cluttered
chromatogram, making peak assignment difficult. In particular,
the more volatile organics (chloroethanes, ethyl toluenes, dichloro-
benzenes, and various freons) exhibit less well defined chromato-
graphic peaks, leading to misidentification using non-specific
detectors. Quantitative comparisons indicate that the FID is more
subject to error than the ECD because the ECD is a much more selec-
tive detector for a smaller class of compounds which exhibits a
stronger response. Identification errors, however, can be reduced
by: (a) employing simultaneous detection by different detectors
or (b) correlating retention times from different GC columns for
confirmation. In either case, interferences on the non-specific
detectors can still cause error in identifying a complex sample.
The non-specific detector system (GC-NPD-FID-ECD-PID), however,
has been used for approximate quantitation of relatively clean
samples. The nonspecific detector system can provide a "snapshot"
of the constituents in the sample, allowing determination of:
- Extent of misidentification due to overlapping peaks,
- Position of the VOCs within or not within the concentration
range of anticipated further analysis by specific detectors
(GC-MS-SCAN-SIM) (if not, the sample is further diluted), and
- Existence of unexpected peaks which need further identification
by specific detectors.
On the other hand, the use of specific detectors (MS coupled to a
GC) allows positive compound identification, thus lending itself
to more specificity than the multidetector GC. Operating in the
SIM mode, the MS can readily approach the same sensitivity as the
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T014-4
multidetector system, but its flexibility is limited. For SIM
operation, the MS is programmed to acquire data for a limited
number of targeted compounds while disregarding other acquired
information. In the SCAN mode, however, the MS becomes a universal
detector, often detecting compounds which are not detected by
the multidetector approach. The GC-MS-SCAN will provide positive
identification, while the GC-MS-SIM procedure provides quantitation
of a restricted "target compound" list of VOCs.
The analyst often must decide whether to use specific or non-
specific detectors by considering such factors as project objectives,
desired detection limits, equipment availability, cost and
personnel capability in developing an analytical strategy.
A list of some of the advantages and disadvantages associated
with non-specific and specific detectors may assist the
analyst in the decision-making process.
Non-Specific Multidetector Analytical System
Advantages
o Somewhat lower equipment
cost than GC-MS
o Less sample volume required
for analysis
o More sensitive
- ECD may be 1000 times
more sensitive than
GC-MS
Disadvantages
o Multiple detectors to calibrate
o Compound identification not
positive
o Lengthy data interpretation
(one hour each for analysis
and data reduction)
o Interference(s) from co-eluting
compound(s)
o Cannot identify unknown
compounds
- outside range of cali-
bration
- without standards
o Does not differentiate
targeted compounds from
interfering compounds
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T014-5
Specific Detector Analytical System
GC-MS-SIM
o
o
Advantages
positive compound identification
greater sensitivity than GC-MS-
SCAN
o less operator interpretation
than for multidetector GC
o can resolve co-eluting peaks
o more specific than the multi-
detector GC
GC-MS-SCAN
o positive compound identification
o can identify all compounds
o less operator interpretation
o can resolve co-eluting peaks
Disadvantages
o can't identify non-specified
compounds (ions)
o somewhat greater equipment
cost than multidetector GC
o greater sample volume required
than for multidetector GC
o universality of detector sac-
rificed to achieve enhance-
ment in sensitivity
o lower sensitivity than GC-MS-
SIM
o greater sample volume required
than for multidetector GC
o somewhat greater equipment cost
than multidetector GC
The analytical finish for the measurement chosen by the analyst
should provide a definitive identification and a precise quanti-
tation of volatile organics. In a large part, the actual approach
to these two objectives is subject to equipment availability.
Figure 1 indicates some of the favorite options that are used as
an analytical finish. The GC-MS-SCAN option uses a capillary
column GC coupled to a MS operated in a scanning mode and sup-
ported by spectral library search routines. This option offers
the nearest approximation to unambiguous identification and
covers a wide range of compounds as defined by the completeness
of the spectral library. GC-MS-SIM mode is limited to a set of
target compounds which are user defined and is more sensitive
than GC-MS-SCAN by virtue of the longer dwell times at the
restricted number of m/z values. Both these techniques, but
especially the GC-MS-SIM option, can use a supplemental general
non-specific detector to verify/identify the presence of VOCs.
Finally, the option labelled GC-multidetector system uses a
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combination of retention time and multiple general detector veri-
fication to identify compounds. However, interference due to
nearly identical retention times can affect system quantitation
when using this option.
Due to the low concentrations of VOCs encountered in urban air
(typically less than 4 ppbv and the majority below 1 ppbv) along
with their complicated chromatograms, Method TO-14 strongly recommends
the specific detectors (GC-MS-SCAN-SIM) for positive identification
and for primary quantitation to ensure that high-quality ambient
data is acquired.
For the experienced analyst whose analytical system is limited to the
non-specific detectors, Section 10.3 does provide guidelines and
example chromatograms showing typical retention times and calibra-
tion response factors, and utilizing the non-specific detectors
(GC-FID-ECD-PID) analytical system as the primary quantitative
technique.
4. Significance
4.1 VOCs enter the atmosphere from a variety of sources, including
petroleum refineries, synthetic organic chemical plants, natural
gas processing plants, and automobile exhaust. Many of these
VOCs are acutely toxic; therefore, their determination in ambient
air is necessary to assess human health impacts.
4.2 Conventional methods for VOC determination use solid sorbent sampl-
ing techniques. The most widely used solid sorbent is Tenax®. An
air sample is drawn through a Tenax®-filled cartridge where certain
VOCs are trapped on the polymer. The sample cartridge is transferred
to a laboratory and analyzed by GC-MS.
4.3 VOCs can also be successfully collected in stainless steel canisters.
Collection of ambient air samples in canisters provides (1) conven-
ient integration of ambient samples over a specific time period,
(e.g., 24 hours); (2) remote sampling and central analysis; (3)
ease of storing and shipping samples; (4) unattended sample col-
lection; (5) analysis of samples from multiple sites with one
analytical system; and (6) collection of sufficient sample volume
to allow assessment of measurement precision and/or analysis of
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T014-7
samples by several analytical systems. However, care must be exer-
cised in selecting, cleaning, and handling sample canisters and
sampling apparatus to avoid losses or contamination of the samples,
Contamination is a critical issue with canister-based sampling be-
• cause the canister is the last element in the sampling train.
4.4 Interior surfaces of the canisters are treated by the SUMMA®
passivation process, in which a pure chrome-nickel oxide is
formed on the surface. This type of vessel has been used in the
past for sample collection and has demonstrated sample storage
stability of many specific organic compounds.
4.5 This method can be applied to sampling and analysis of not only
VOCs, but also some selected semi volatile organic compounds
(SVOCs). The term "semivolatile organic compounds" is used to
broadly describe organic compounds that are too volatile to be
collected by filtration air sampling but not volatile enough for
thermal desorption from solid sorbents. SVOCs can generally be
classified as those with saturation vapor pressures at 25°C be-
tween 10-1 and 10~7 mm Hg. VOCs are generally classified as
those organics having saturated vapor pressures at 25°C greater
than 10"1 mm Hg.
5. Definitions
Note: Definitions used in this document and in any user-prepared
Standard Operating Procedures (SOPs) should be consistent with ASTM
Methods D1356, E260, and E355. All abbreviations and symbols within
this method are defined at point of use.
5.1 Absolute canister pressure = Pg+Pa, where Pg = gauge pressure in
the canister (kPa, psi) and Pa = barometric pressure (see 5.2).
5.2 Absolute pressure - Pressure measured with reference to absolute
zero pressure (as opposed to atmospheric pressure), usually
expressed as kPa, mm Hg or psia.
5.3 Cryogen - A refrigerant used to obtain very low temperatures in
the cryogenic trap of the analytical system. A typical cryogen
is liquid oxygen (bp -183.0°C) or liquid argon (bp -185.7°C).
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T014-8
5.4 Dynamic calibration - Calibration of an analytical system using
calibration gas standard concentrations in a form identical or
very similar to the samples to be analyzed and by introducing
such standards into the inlet of the sampling or analytical
system in a manner very similar to the normal sampling or
analytical process.
5.5 Gauge pressure - Pressure measured above ambient atmospheric
pressure (as opposed to absolute pressure). Zero gauge pressure
is equal to ambient atmospheric (barometric) pressure.
5.6 MS-SCAN - The GC is coupled to a MS programmed in the SCAN mode
to scan all ions repeatedly during the GC run. As used in the
current context, this procedure serves as a qualitative identi-
fication and characterization of the sample.
5.7 MS-SIM - The GC is coupled to a MS programmed to acquire data
for only specified ions and to disregard all others. This is
performed using SIM coupled to retention time discriminators.
The GC-SIM analysis provides quantitative results for selected
constituents of the sample gas as programmed by the user.
5.8 Megabore* column - Chromatographic column having an internal di-
ameter (I.D.) greater than 0.50 mm. The Megabore* column is a
trademark of the J&W Scientific Co. For purposes of this
method, Megabore* refers to Chromatographic columns with 0.53
mm I.D.
5.9 Pressurized sampling - Collection of an air sample in a canister
with a (final) canister pressure above atmospheric pressure,
using a sample pump.
5.10 Qualitative accuracy - The ability of an analytical system to
correctly identify compounds.
5.11 Quantitative accuracy - The ability of an analytical system to
correctly measure the concentration of an identified compound.
5.12 Static calibration - Calibration of an analytical system using
standards in a form different than the samples to be analyzed.
An 'example of a static calibration would be injecting a small
volume of a high concentration standard directly onto a GC
column, bypassing the sample extraction and preconcentration
portion of the analytical system.
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T014-9
5.13 Suba tiros pheric sampling - Collection of an air sample in an
evacuated canister at a (final) canister pressure below atmos-
pheric pressure, without the assistance of a sampling pump. The
canister is filled as the internal canister pressure increases
to ambient or near ambient pressure. An auxiliary vacuum pump
may be used as part of the sampling system to flush the inlet
tubing prior to or during sample collection.
6. Interferences and Limitations
6.1 Interferences can occur in sample analysis if moisture accumu-
lates in the dryer (see Section 10.1.1.2). An automated cleanup
procedure that periodically heats the dryer to about 100°C while
purging with zero air eliminates any moisture buildup. This pro-
cedure does not degrade sample integrity.
6.2 Contamination may occur in the sampling system if canisters are
not properly cleaned before use. Additionally, all other sampling
equipment (e.g., pump and flow controllers) should be thoroughly
cleaned to ensure that the filling apparatus will not contaminate
samples. Instructions for cleaning the canisters and certifying
the field sampling system are described in Sections 12.1 and 12.2,
respectively.
6.3 Because the GC-MS analytical system employs a Nafion* permeable
membrane dryer to remove water vapor selectively from the sample
stream, polar organic compounds may permeate concurrent with the
moisture molecule. Consequently, the analyst should quantitate
his or her system with the specific organic constituents under
examination.
7. Apparatus
7.1 Sample Collection
[Note: Subatmospheric pressure and pressurized canister sampling
systems are commercially available and have been used as part of
U.S. Environmental Protection Agency's Toxics Air Monitoring
Stations (TAMS), Urban Air Toxic Pollutant Program (UATP), and
the non-methane organic compound (NMOC) sampling and analysis
program.]
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T014-10
7.1.1 Subatmospheric Pressure (See Figure 2 Without Metal Bellows
Type Pump)
7.1.1.1 Sampling inlet line - stainless steel tubing to
connect the sampler to the sample inlet.
7.1.1.2 Sample canister - leak-free stainless steel pressure
vessels of desired volume (e.g., 6 L), with valve
and SUMMA® passivated interior surfaces (Scientific
Instrumentation Specialists, Inc., P.O. Box 8941,
Moscow, ID 83843, or Anderson Samplers, Inc., 4215-C
Wendell Dr., Atlanta, GA, 30336, or equivalent).
7.1.1.3 Stainless steel vacuum/pressure gauge - capable of '
measuring vacuum (-100 to 0 kPa or 0 to 30 in Hg)
and pressure (0-206 kPa or 0-30 psig) in the sampling
system (Matheson, P.O. Box 136, Morrow, GA 30200,
Model 63-3704, or equivalent). Gauges should be
tested clean and leak tight.
7.1.1.4 Electronic mass flow controller - capable of main-
taining a constant flow rate (_+ 10%) over a sampl-
ing period of up to 24 hours and under conditions
of changing temperature (20-40°C) and humidity
(Tylan Corp., 19220 S. Normandie Ave., Torrance,
CA 90502, Model FC-260, or equivalent).
7.1.1.5 Particulate matter filter - 2-um sintered stainless
steel in-line filter (Nupro Co., 4800 E. 345th St.,
Willoughby, OH 44094, Model SS-2F-K4-2, or equiva-
lent).
7.1.1.6 Electronic timer - for unattended sample collection
(Paragon Elect. Co., 606 Parkway Blvd., P.O. Box 28,
Twin Rivers, WI 54201, Model 7008-00, or equivalent).
7.1.1.7 Solenoid valve - electrically-operated, bi-stable
solenoid valve (Skinner Magnelatch Valve, New
Britain, CT, Model V5RAM49710, or equivalent) with
Viton® seat and o-rings.
7.1.1.8 Chromatographic grade stainless steel tubing and
fittings - for interconnections (Alltech Associates,
2051 Waukegan Rd., Deerfield, IL 60015, Cat. #8125,
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T014-11
or equivalent). All such materials in contact with
sample, analyte, and support gases prior to analy-
sis should be chromatographic grade stainless steel.
7.1.1.9 Thermostatically controlled heater - to maintain
temperature inside insulated sampler enclosure above
ambient temperature (Watlow Co., Pfafftown, NC,
Part 04010080, or equivalent).
7.1.1.10 Heater thermostat - automatically regulates heater
temperature (Elmwood Sensors, Inc., 500 Narragansett
Park Dr., Pawtucket RI 02861, Model 3455-RC-0100-
0222, or equivalent).
7.1.1.11 Fan - for cooling sampling system (EG&6 Rotron,
Woodstock, NY, Model SUZAI, or equivalent).
7.1.1.12 Fan thermostat - automatically regulates fan opera-
tion (Elmwood Sensors, Inc., Pawtucket, RI, Model
3455-RC-0100-0244, or equivalent).
7.1.1.13 Maximum-minimum thermometer - records highest and
lowest temperatures during sampling period (Thomas
Scientific, Brooklyn Thermometer Co., Inc.,
P/N 9327H30, or equivalent).
7.1.1.14 Nupro stainless steel shut-off valve - leak free,
for vacuum/pressure gauge.
7.1.1.15 Auxiliary vacuum pump - continuously draws ambient
air to be sampled through the inlet manifold at 10
L/min. or higher flow rate. Sample is extracted
from the manifold at a lower rate, and excess air
is exhausted. [Note: The use of higher inlet flow
rates dilutes any contamination present in the inlet
and reduces the possibility of sample contamination
as a result of contact with active adsorption sites
on inlet walls.]
7.1.1.16 Elapsed time meter - measures duration of sampling
(Conrac, Cramer Div., Old Saybrook, CT, Type 6364,
P/N 10082, or equivalent).
7.1.1.17 Optional fixed orifice, capillary, or adjustable
micrometer!ng valve - may be used in lieu of the
electronic flow controller for grab samples or short
duration time-integrated samples. Usually appropri-
ate only 1n situations where screening ^mple are
taken to assess future sampling activity.
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7.1.2 Pressurized (Figure 2 With Metal Bellows Type Pump and Figure 3)
7.1.2.1 Sample pump - stainless steel, metal bellows type
(Metal Bellows Corp., 1075 Providence Highway,
Sharon, MA 02067, Model MB-151, or equivalent),
capable of 2 atmospheres output pressure. Pump must
be free of leaks, clean, and uncontaminated by oil
or organic compounds. [Note: An alternative sampl-
ing system has been developed by Dr. R. Rasmussen,
The Oregon Graduate Center (18,19) and is illustrated
in Figure 3. This flow system uses, in order, a
pump, a mechanical flow regulator, and a mechanical
compensating flow restrictive device. In this con-
figuration the pump is purged with a large sample
flow, thereby eliminating the need for an auxiliary
vacuum pump to flush the sample inlet. Interferences
using this configuration have been minimal.]
7.1.2.2 Other supporting materials - all other components of
the pressurized sampling system (Figure 2 with metal
bellows type pump and Figure 3) are similar to compo-
nents discussed in Sections 7.1.1.1 through 7.1.1.16.
7.2 Sample Analysis
7.2.1 GC-MS-SCAN Analytical System (See Figure 4)
7.2.1.1 The GC-MS-SCAN analytical system must be capable of
acquiring and processing data in the MS-SCAN mode.
7.2.1.2 Gas chromatograph - capable of sub-ambient tempera-
ture programming for the oven, with other generally
standard features such as gas flow regulators, auto-
matic control of valves and integrator, etc. Flame
ionization detector optional. (Hewlett Packard,
Rt. 41, Avondale, PA 19311, Model 5880A, with oven
temperature control and Level 4 BASIC programming,
or equivalent.)
7.2.1.3 Chromatographic dstector - mass-selective detector
(Hewlett Packard, 3000-T Hanover St., 9B, Palo Alto,
CA 94304, Model HP-5970 MS, or equivalent), equipped
with computer and appropriate software (Hewlett
Packard, 3000-T Hanover St., 9B, Palo Alto, CA 94304,
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T014-13
HP-216 Computer, Quicksilver MS software, Pascal
3.0, mass storage 9133 HP Winchester with 3.5 inch
floppy disk, or equivalent). The GC-MS is set in
the SCAN mode, where the MS screens the sample for
identification and quantitation of VOC species.
7.2.1.4 Cryogenic trap with temperature control assembly -
refer to Section 10.1.1.3 for complete description
of trap and temperature control assembly (Nutech
Corporation, 2142 Geer St., Durham, NC, 27704,
Model 320-01, or equivalent).
7.2.1.5 Electronic mass flow controllers (3) - maintain
constant flow (for carrier gas and sample gas) and
to provide analog output to monitor flow anomalies
(Tylan Model 260, 0-100 cm3/min, or equivalent).
7.2.1.6 Vacuum pump - general purpose laboratory pump,
capable of drawing the desired sample volume through
the cryogenic trap (Thomas Industries, Inc., Sheboygan,
WI, Model 107BA20, or equivalent).
7.2.1.7 Chromatographic grade stainless steel tubing and
stainless steel plumbing fittings - refer to Section
7.1.1.8 for description.
7.2.1.8 Chromatographic column - to provide compound separation
such as shown in Table 5 (Hewlett Packard, Rt. 41,
Avondale, PA 19311, OV-1 capil lary column, 0.32 mm x
50 m with 0.88 urn crossi inked methyl silicone coating,
or equivalent).
7.2.1.9 Stainless steel vacuum/pressure gauge (optional) -
capable of measuring vacuum (-101.3 to 0 kPa) and pres-
sure (0-206 kPa) in the sampling system (Matheson, P.O.
Box 136, Morrow, GA 30200, Model 63-3704, or equiva-
lent). Gauges should be tested clean and leak tight.
7.2.1.10 Stainless steel cylinder pressure regulators - standard,
two-stage cylinder regulators with pressure gauges for
helium, zero air and hydrogen gas cylinders.
7.2.1.11 Gas purifiers (3) - used to remove organic impurities
and moisture from gas streams (Hewlett Packard, Rt. 41,
Avondale, PA, 19311, P/N 19362 - 60500, or equivalent).
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7.2.1.12 Low dead-volume tee (optional) - used to split the
exit flow from the GC column (Alltech Associates,
2051 Waukegan Rd., Deerfield, IL 60015, Cat. #5839,
or equivalent).
7.2.1.13 Nafion® dryer - consisting of Nafion tubing co-
axially mounted within larger tubing (Perma Pure
Products, 8 Executive Drive, Toms River, NJ, 08753,
Model MD-125-48, or equivalent). Refer to Section
10.1.1.2 for description.
7.2.1.14 Six-port gas chromatographic valve - (Seismograph
Service Corp, Tulsa, OK, Seiscor Model VIII, or
equivalent).
7.2.1.15 Chart recorder (optional) - compatible with the
detector output signals to record optional FID
detector response to the sample.
7.2.1.16 Electronic integrator (optional) - compatible
with the detector output signal of the FID and
capable of integrating the area of one or more
response peaks and calculating peak areas cor-
rected for baseline drift.
7.2.2 GC-MS-SIM Analytical System (See Figure 4)
7.2.2.1 The GC-MS-SIM analytical system must be capable of
acquiring and processing data in the MS-SIM mode.
7.2.2.2 All components of the GC-MS-SIM system are identi-
cal to Sections 7.2.1.2 through 7.2.1.16.
7.2.3 GC-Multidetector Analytical System (See Figure 5 and Figure 6)
7.2.3.1 Gas chromatograph with flame ionization and elec-
tron capture detectors (photoionization detector
optional) - capable of sub-ambient temperature
programming for the oven and simultaneous opera-
tion of all detectors, and with other generally
standard features such as gas flow regulators,
automatic control of valves and integrator, etc.
(Hewlett Packard, Rt. 41, Avondale, PA 19311,
Model 5880A, with oven temperature control and
Level 4 BASIC programming, or equivalent).
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7.2.3.2 Chart recorders - compatible with the detector output
signals to record detector response to the sample.
7.2.3.3 Electronic integrator - compatible with the detec-
tor output signals and capable of integrating the
area of one or more response peaks and calculating
peak areas corrected for baseline drift.
7.2.3.4 Six-port gas chromatographic valve - (Seismograph Ser-
vice Corp, Tulsa, OK, Seiscor Model VIII, or equivalent),
7.2.3.5 Cryogenic trap with temperature control assembly -
refer to Section 10.1.1.3 for complete description of
trap and temperature control assembly (Nutech Corpora-
tion, 2142 Geer St., Durham, NC 27704, Model 320-01,
or equivalent).
7.2.3.6 Electronic mass flow controllers (3) - maintain con-
stant flow (for carrier gas, nitrogen make-up gas and
sample gas) and to provide analog output to monitor
flow anomalies (Tylan Model 260, 0-100 cm3/min, or
equivalent).
7.2.3.7 Vacuum pump - general purpose laboratory pump, capable
of drawing the desired sample volume through the cry-
ogenic trap (see 7.2.1.6 for source and description).
7.2.3.8 Chromatographic grade stainless steel tubing and stain-
less steel plumbing fittings - refer to Section 7.1.1.8
for description.
7.2.3.9 Chromatographic column - to provide compound separation
such as shown in Table 7. (Hewlett Packard, Rt. 41,
Avondale, PA 19311, OV-1 capillary column, 0.32
mm x 50 m with 0.88 urn crosslinked methyl silicone
coating, or equivalent). [Note: Other columns
(e.g., DB-624) can be used as long as the system
meets user needs. The wider Megabore® column (i.e.,
0.53 mm I.D.) is less susceptible to plugging as
a result of trapped water, thus eliminating the
need for a Nafion® dryer in the analytical system.
The Megabore® column has sample capacity approaching
that of a packed column, while retaining much of
the peak resolution traits of narrower columns
(i.e., 0.32 mm I.D.).
-------
T014-16
7.2.3.10 Vacuum/pressure gauges (3) - refer to Section
7.2.1.9 for description.
7.2.3.11 Cylinder pressure stainless steel regulators -
standard, two-stage cylinder regulators with
pressure gauges for helium, zero air, nitrogen,
and hydrogen gas cylinders.
7.2.3.12 Gas purifiers (4) - used to remove organic
impurities and moisture from gas streams (Hewlett-
Packard, Rt. 41, Avondale, PA, 19311, P/N 19362 -
60500, or equivalent).
7.2.3.13 Low dead-volume tee - used to split (50/50) the
exit flow from the GC column (Alltech Associates,
2051 Waukegan Rd., Deerfield, IL 60015, Cat.
#5839, or equivalent).
7.3 Canister Cleaning System (See Figure 7)
7.3.1 Vacuum pump - capable of evacuating sample canister(s) to
an absolute pressure of <0.05 mm Hg.
7.3.2 Manifold - stainless steel manifold with connections for
simultaneously cleaning several canisters.
7.3.3 Shut-off valve(s) - seven (7) on-off toggle valves.
7.3.4 Stainless steel vacuum gauge - capable of measuring vacuum
in the manifold to an absolute pressure of 0.05 mm Hg or
less.
7.3.5 Cryogenic trap (2 required) - stainless steel U-shaped open
tubular trap cooled with liquid oxygen or argon to prevent
contamination from back diffusion of oil from vacuum pump
and to provide clean, zero air to sample canister(s).
7.3.6 Stainless steel pressure gauges (2) - 0-345 kPa (0-50 psig)
to monitor zero air pressure.
7.3.7 Stainless steel flow control valve - to regulate flow of
zero air into canister(s).
7.3.8 Humidifier - pressurizable water bubbler containing high
performance liquid chromatography (HPLC) grade deionized
water or other system capable of providing moisture to the
zero air supply.
7.3.9 Isothermal oven (optional) for heating canisters (Fisher
Scientific, Pittsburgh, PA, Model 349, or equivalent).
-------
T014-17
7.4 Calibration System and Manifold (See Figure 8)
7.4.1 Calibration manifold - glass manifold, (1.25 cm I.D. x 66 cm)
with sampling ports and internal baffles for flow disturbance
to ensure proper mixing.
7.4.2 Humidifier - 500-mL impinger flask containing HPLC grade
deionized water.
7.4.3 Electronic mass flow controllers - one 0 to 5 L/min and
one 0 to 50 cm3/min (Tylan Corporation, 23301-TS Wilmington
Ave., Carson, CA, 90745, Model 2160, or equivalent).
7.4.4 Teflon® filter(s) - 47-mm Teflon® filter for particulate
control, best source.
8. Reagents and Materials
8.1 Gas cylinders of helium, hydrogen, nitrogen, and zero air -
ultrahigh purity grade, best source.
8.2 Gas calibration standards - cylinder(s) containing approximately
10 ppmv of each of the following compounds of interest:
vinyl chloride
vinylidene chloride
l,l,2-trichloro-l,2,2-
trifluoroethane
chloroform
1,2-dichloroethane
benzene
toluene
Freon 12
methyl chloride
l,2-dichloro-l,l,2
methyl bromide
ethyl chloride
Freon 11
dichloromethane
1,1-dichloroethane
ci s-1,2-dichloroethylene
1,2-dichloropropane
1,1,2-trichloroethane
2-tetrafluoroethane
1,2-dibromoethane
tetrachloroethylene
chlorobenzene
benzyl chloride
hexachloro-1,3-butadiene
methyl chloroform
carbon tetrachloride
trichloroethylene
cis-l,3-dichloropropene
trans-1,3-di chloropropene
ethyl benzene
o-xylene
m-xylene
p-xylene
styrene
1,1,2,2-tetrachloroethane
1,3,5-trimethyl benzene
1,2,4-trimethylbenzene
m-dichlorobenzene
o-dichlorobenzene
p-dichlorobenzene
1,2,4-trichlorobenzene
-------
T014-18
The cylinder(s) should be traceable to a National Bureau of
Standards (NBS) Standard Reference Material (SRM) or to a NBS/EPA
approved Certified Reference Material (CRM). The components may
be purchased in one cylinder or may be separated into different
cylinders. Refer to manufacturer's specification for guidance on
purchasing and mixing VOCs in gas cylinders. Those compounds
purchased should match one's own target list.
8.3 Cryogen - liquid oxygen (bp -183.0°C), or liquid argon (bp
-185.7°C), best source.
8.4 Gas purifiers - connected in-line between hydrogen, nitrogen, and
zero air gas cylinders and system inlet line, to remove moisture
and organic impurities from gas streams (Alltech Associates,
2051 Waukegan Road, Deerfield, Il_, 60015, or equivalent).
8.5 Deionized water - high performance liquid chromatography (HPLC)
grade, ultrahigh purity (for humidifier), best source.
8.6 4-bromofluorobenzene - used for tuning 6C-MS, best source.
8.7 Hexane - for cleaning sampling system components, reagent grade,
best source.
8.8 Methanol - for cleaning sampling system components, reagent grade,
best source.
9. Sampling System
9.1 System Description
9.1.1 Subatmospheric Pressure Sampling [See Figure 2 (Without Metal
Bel lows Type Pump)]
9.1.1.1 In preparation for subatmospheric sample collec-
tion in a canister, the canister is evacuated to
0.05 mm Hg. When opened to the atmosphere con-
taining the VOCs to be sampled, the differential
pressure causes the sample to flow into the can-
ister. This technique may be used to collect grab
samples (duration of 10 to 30 seconds) or time-
integrated samples (duration of 12 to 24 hours)
taken through a flow-restrictive inlet (e.g.,
mass flow controller, critical orifice).
-------
T014-19
9.1.1.2 With a critical orifice flow restrictor, there will
be a decrease in the flow rate as the pressure
approaches atmospheric. However, with a mass flow
controller, the subatmospheric sampli-ng system can
maintain a constant flow rate from full vacuum to
within about 7 kPa (1.0 psi) or less below ambient
pressure.
9.1.2 Pressurized Sampling [See Figure 2 (With Metal Bellows Type Pump)]
9.1.2.1 Pressurized sampling is used when longer-term inte-
grated samples or higher volume samples are required.
The sample is collected in a canister using a pump
and flow control arrangement to achieve a typical
103-206 kPa (15-30 psig) final canister pressure.
For example, a 6-liter evacuated canister can be
filled at 10 cm3/min for 24 hours to achieve a final
pressure of about 144 kPa (21 psig).
9.1.2.2 In pressurized canister sampling, a metal bellows type
pump draws in ambient air from the sampling manifold
to fill and pressurize the sample canister.
9.1.3 All Samplers
9.1.3.1 A flow control device is chosen to maintain a constant
flow into the canister over the desired sample period.
This flow rate is determined so the canister is filled
(to about 88.1 kPa for subatmospheric pressure sampl-
ing or to about one atmosphere above ambient pressure
for pressurized sampling) over the desired sample
period. The flow rate can be calculated by
F = P x V
T x 60
where:
F = flow rate (cm3/min).
P = final canister pressure, atmospheres
absolute. P is approximately equal to
+ 1
qannp
1.
101.2
-------
T014-20
V = volume of the canister (cm3).
T = sample period (hours).
For example, if a 6-L canister is to-be filled
to 202 kPa (2 atmospheres) absolute pressure in
24 hours, the flow rate can be calculated by
F = 2 x 6000 = 8.3 cm3/min
24 x 60
9.1.3.2 For automatic operation, the timer is wired to start
and stop the pump at appropriate times for the desired
sample period. The timer must also control the sole-
noid valve, to open the valve when starting the pump
and close the valve when stopping the pump.
9.1.3.3 The use of the Skinner Magnelatch valve avoids any
substantial temperature rise that would occur with
a conventional, normally closed solenoid valve that
would have to be energized during the entire sample
period. The temperature rise in the valve could
cause outgassing of organic compounds from the Vi;
valve seat material. The Skinner Magnelatch
valve requires only a brief electrical pulse to
open or close at the appropriate start and stop
times and therefore experiences no temperature
increase. The pulses may be obtained either
with an electronic timer that can be programmed
for short (5 to 60 seconds) ON periods, or with
a conventional mechanical timer and a special
pulse circuit. A simple electrical pulse circuit
for operating the Skinner Magnelatch solenoid valve
with a conventional mechanical timer is illustrated
in Figure 9(a). However, with this simple circuit,
the valve may operate unreliably during brief
power interruptions or if the timer is manually
switched on and off too fast. A better circuit in-
corporating a time-delay relay to provide more re-
liable valve operation is shown in Figure 9(b).
-------
TO14-21
9.1.3.4 The connecting lines between the sample inlet and the
canister should be as short as possible to minimize
their volume. The flow rate into the canister should
remain relatively constant over the entire sampling
period. If a critical orifice is used, some drop in
the flow rate may occur near the end of the sample
period as the canister pressure approaches the final
calculated pressure.
9.1.3.5 As an option, a second electronic timer (see Sec-
tion 7.1.1.6) may be used to start the auxiliary
pump several hours prior to the sampling period
to flush and condition the inlet line.
9.1.3.6 Prior to field use, each sampling system must pass
a humid zero air certification (see Section 12.2.2).
All plumbing should be checked carefully for leaks.
The canisters must also pass a humid zero air certi-
fication before use (see Section 12.1).
9.2 Sampling Procedure
9.2.1 The sample canister should be cleaned and tested according
to the procedure in Section 12.1.
9.2.2 A sample collection system is assembled as shown in Figure 2
(and Figure 3) and must meet certification requirements as
outlined in Section 12.2.3. [Note: The sampling system
should be contained in an appropriate enclosure.]
9.2.3 Prior to locating the sampling system, the user may want to
perform "screening analyses" using a portable GC system,
as outlined in Appendix B, to determine potential volatile
organics present and potential "hot spots." The information
gathered from the portable GC screening analysis would be
used in developing a monitoring protocol, which includes the
sampling system location, based upon the "screening analysis"
results.
9.2.4 After "screening analysis," the sampling system is located.
Temperatures of ambient air and sampler box interior are
recorded on canister sampling field data sheet (Figure 10).
[Note: The following discussion is related to Figure 2.]
-------
T014-22
9.2.5 To verify correct sample flow, a "practice" (evacuated)
canister is used in the sampling system. [Note: For a
subatmospheric sampler, the flow meter and practice can-
ister are needed. For the pump-driven system., the practice
canister is not needed, as the flow can be measured at
the outlet of the system.] A certified mass flow meter
is attached to the inlet line of the manifold, just in
front of the filter. The canister is opened. The sampler
is turned on and the reading of the certified mass flow
meter is compared to the sampler mass flow controller.
The values should agree within +10%. If not, the sampler
mass flow meter needs to be recalibrated or there is a
leak in the system. This should be investigated and
corrected. [Note: Mass flow meter readings may drift.
Check the zero reading carefully and add or subtract the
zero reading when reading or adjusting the sampler flow
rate, to compensate for any zero drift.] After two minutes,
the desired canister flow rate is adjusted to the proper
value (as indicated by the certified mass flow meter) by
the sampler flow control unit controller (e.g., 3.5
cm3/min for 24 hr, 7.0 cm3/min for 12 hr). Record final
flow under "CANISTER FLOW RATE," Figure 10.
9.2.6 The sampler is turned off and the elapsed time meter is
reset to 000.0. Note: Any time the sampler is turned
off, wait at least 30 seconds to turn the sampler back on.
9.2.7 The "practice" canister and certified mass flow meter
are disconnected and a clean certified (see Section 12.1)
canister is attached to the system.
9.2.8 The canister valve and vacuum/pressure gauge valve are opened.
9.2.9 Pressure/vacuum in the canister is recorded on the canister
sampling field data sheet (Figure 10) as indicated by the
sampler vacuum/pressure gauge.
9.2.10 The vacuum/pressure gauge valve is closed and the maximum-
minimum thermometer is reset to current temperature. Time
of day and elapsed time meter readings are recorded on the
canister sampling field data sheet.
9.2.11 The electronic timer is set to begin and stop the sampling
period at the appropriate times. Sampling commences and
stops by the programmed electronic timer.
-------
T014-23
9.2.12 After the desired sampling period, the maximum, minimum,
current interior temperature and current ambient temper-
ature are recorded on the sampling field data sheet. The
current reading from the flow controller is recorded.
9.2.13 At the end of the sampling period, the vacuum/pressure
gauge valve on the sampler is briefly opened and closed
and the pressure/vacuum is recorded on the sampling field
data sheet. Pressure should be close to desired pressure.
[Note: For a subatmospheric sampling system, if the
canister is at atmospheric pressure when the field final
pressure check is performed, the sampling period may be
suspect. This information should be noted on the sampl-
ing field data sheet.] Time of day and elapsed time
meter readings are also recorded.
9.2.14 The canister valve is closed. The sampling line is dis-
connected from the canister and the canister is removed
from the system. For a subatmospheric system, a certi-
fied mass flow meter is once again connected to the in-
let manifold in front of the in-line filter and a "prac-
tice" canister is attached to the Magnelatch valve of
the sampling system. The final flow rate is recorded
on the canister sampling field data sheet (see Figure
10). [Note: For a pressurized system, the final flow
may be measured directly.] The sampler is turned off.
9.2.15 An identification tag is attached to the canister. Can-
ister serial number, sample number, location, and date
are recorded on the tag.
10. Analytical System (See Figures 4, 5 and 6)
10.1 System Description
10.1.1 GC-MS-SCAN System
10.1.1.1 The analytical system is comprised of a GC
equipped with a mass-selective detector set
in the SCAN mode (see Figure 4). All ions
are scanned by the MS repeatedly during the
-------
T014-24
GC run. The system includes a computer and
appropriate software for data acquisition,
data reduction, and data reporting. A 400
cm3 air sample is collected from the canister
into the analytical system. The sample air is
first passed through a Nafion® dryer, through
the 6-port chromatographic valve, then routed
into a cryogenic trap. [Note: While the
GC-multidetector analytical system does not
employ a Nafion® dryer for drying the sample
gas stream, it is used here because the GC-MS
system utilizes a larger sample volume and is
far more sensitive to excessive moisture than
the GC-multidetector analytical system. Mois-
ture can adversely affect detector precision.
The Nafion® dryer also prevents freezing of
moisture on the 0.32 mm I.D. column, which may
cause column blockage and possible breakage.]
The trap is heated (-160°C to 120°C in 60 sec)
and the analyte is injected onto the OV-1 cap-
illary column (0.32 mm x 50 m). [Note: Rapid
heating of the trap provides efficient transfer
of the sample components onto the gas chromato-
graphic column.] Upon sample injection onto
the column, the MS computer is signaled by
the GC computer to begin detection of compounds
which elute from the column. The gas stream
from the GC is scanned within a preselected
range of atomic mass units (amu). For detec-
tion of compounds in Table 1, the range should
be 18 to 250 amu, resulting in a 1.5 Hz repeti-
tion rate. Six (6) scans per eluting chromato-
graphic peak are provided at this rate. The
10-15 largest peaks are chosen by an automated
data reduction program, the three scans nearest
the peak apex are averaged, and a background sub-
traction is performed. A library search is then
performed and the top ten best matches for each
peak are listed. A qualitative characterization
-------
1014-25
of the sample is provided by this procedure. A
typical chromatogram of VOCs determined by 6C-MS-
SCAN is illustrated in Figure Ilia).
10.1.1.2 A Nafion® permeable membrane dryer is used to
remove water vapor selectively from the sample
stream. The permeable membrane consists of
Nafion® tubing (a copolymer of tetrafluoroethylene
and fluorosulfonyl monomer) that is coaxially
mounted within larger tubing. The sample stream
is passed through the interior of the Nafion®
tubing, allowing water (and other light, polar
compounds) to permeate through the walls into a
dry air purge stream flowing through the annular
space between the Nafion® and outer tubing.
[Note: To prevent excessive moisture build-up
and any memory effects in the dryer, a clean-
up procedure involving periodic heating of the
dryer (100°C for 20 minutes) while purging with
dry zero air (500 cm3/min) should be implemented
as part of the user's SOP manual. The clean-up
procedure is repeated during each analysis (see
Section 14, reference 7). Recent studies have
indicated no substantial loss of targeted
VOCs utilizing the above clean-up procedure
(7). This cleanup procedure is particularly
useful when employing cryogenic preconcentration
of VOCs with subsequent GC analysis using a
0.32 mm I.D. column because excess accumulated
water can cause trap and column blockage and
also adversely affect detector precision.
In addition, the improvement in water removal
from the sampling stream will allow analyses
of much larger volumes of sample air in the
event that greater system sensitivity is
required for targeted compounds.]
-------
T014-26
10.1.1.3 The packed metal tubing used for reduced tem-
perature trapping of VOCs is shown in Figure 12.
The cooling unit is comprised of a 0.32 cm out-
side diameter (O.D.) nickel tubing loop packed
with 60-80 mesh Pyrex® beads (Nutech Model
320-01, or equivalent). The nickel tubing loop
is wound onto a cyli ndrical ly formed tube heater
(250 watt). A cartridge heater (25 watt) is
sandwiched between pieces of aluminum plate
at the trap inlet and outlet to provide addi-
tional heat to eliminate cold spots in the
»
transfer tubing. During operation, the trap
is inside a two-section stainless steel shell
which is well insulated. Rapid heating
(-150 to +100°C in 55 s) is accomplished by
direct thermal contact between the heater
and the trap tubing. Cooling is achieved by
vaporization of the cryogen. In the shell,
efficient cooling (+120 to -150°C in 225 s)
is facilitated by confining the vaporized
cryogen to the small open volume surrounding
the trap assembly. The trap assembly and
chromatographic valve are mounted on a
baseplate fitted into the injection and
auxiliary zones of the GC on an insulated
pad directly above the column oven when used
with the Hewlett-Packard 5880 GC. [Note:
Alternative trap assembly and connection to
the GC may be used depending upon user's
requirements.] The carrier gas line is con-
nected to the injection end of the analytical
column with a zero-dead-volume fitting that is
usually held in the heated zone above the GC
oven. A 15 cm x 15 cm x 24 cm aluminum box
is fitted over the sample handling elements
to complete the package. Vaporized cryogen
is ve*ited*'4H£ough the top of the box.
-------
T014-27
10.1.1.4 As an option, the analyst may wish to split
the gas stream exiting the column with a
low dead-volume tee, passing one-third
of the sample gas (1.0 mL/min) te the mass-
selective detector and the remaining two-
thirds (2.0 mL/min) through a flame
ionization detector, as illustrated as an
option in Figure 4. The use of the specific
detector (MS-SCAN) coupled with the non-
specific detector (FID) enables enhancement
of data acquired from a single analysis. In
particular, the FID provides the user:
o Semi-real time picture of the progress
of the analytical scheme;
o Confirmation by the concurrent MS
analysis of other labs that can provide
only FID results; and
o Ability to compare GC-FID with other
analytical laboratories with only GC-
FID capability.
10.1.2 GC-MS-SIM System
10.1.2.1 The analytical system is comprised of a GC
equipped with an OV-1 capillary column (0.32 mm
x 50 m) and a mass-selective detector set in
the SIM mode (see Figure 4). The GC-MS is
set up for automatic, repetitive analysis.
The system is programmed to acquire data for
only the target compounds and to disregard
all others. The sensitivity is 0.1 ppbv for
a 250 cm-* air sample with analytical precision
of about 5% relative standard deviation. Con-
centration of compounds based upon a previously
installed calibration table is reported by an
automated data reduction program. A Nafion®
dryer is also employed by this analytical sys-
tem prior to cryogenic preconcentration; there-
fore, many polar compounds are not identified
by this procedure.
-------
T014-28
10.1.2.2 SIM analysis is based on a combination of reten-
tion times and relative abundances of selected
ions (see Table 2). These qualifiers are stored
on the hard disk of the GC-MS computer and are
applied for identification of each chromato-
graphic peak. The retention time qualifier is
determined to be j^ 0.10 minute of the library
retention time of the compound. The acceptance
level for relative abundance is determined to
be jf 15% of the expected abundance, except for
vinyl chloride and methylene chloride, which
is determined to be _+ 25%. Three ions are mea-
sured for most of the forty compounds. When
compound identification is made by the computer,
any peak that fails any of the qualifying tests
is flagged (e.g., with an .*). All the data
should be manually examined by the analyst
to determine the reason for the flag and
whether the compound should be reported as
found. While this adds some subjective
judgment to the analysis, computer-generated
identification problems can be clarified by
an experienced operator. Manual inspection
of the quantitative results should also be
performed to verify concentrations outside
the expected range. A typical chromatogram
of VOCs determined by GC-MS-SIM mode is
illustrated in Figure ll(b).
10.1.3 GC-Multidetector (GC-FID-ECD) System with Optional PID
10.1.3.1 The analytical system (see Figure 5) is
comprised of a gas chromatograph equipped
with a capillary column and electron capture
and flame ionization detectors (see Figure 5).
In typical operation, sample air from pressur-
ized canisters is vented past the inlet to
the analytical system from the canister at a
flow rate of 75 cm3/min. For analysis, only
35 cm3/min of sample gas is used, while excess
-------
T014-29
is vented to the atmosphere. Sub-ambient
pressure canisters are connected directly to
the inlet. The sample gas stream is routed
through a six port chromatographic valve and
into the cryogenic trap for a total sample
volume of 490 cm3. [Note: This represents a
14 minute sampling period at a rate of 35
cm3/min.] The trap (see Section 10.1.1.3)
is cooled to -150°C by controlled release of
a cryogen. VOCs and SVOCs are condensed on
the trap surface while N2, 02, and other sample
components are passed to the pump. After the
organic compounds are concentrated, the valve
is switched and the trap is heated. The revola-
tilized compounds are transported by helium
carrier gas at a rate of 4 cm3/min to the
head of the Megabore® OV-1 capillary column
(0.53 mm x 30 m). Since the column initial
temperature is at -50°C, the VOCs and SVOCs
are cryofocussed on the head of the column.
Then, the oven temperature is programmed to
increase and the VOCs/SVOCs in the carrier gas
are chromatographically separated. The carrier
gas containing the separated VOCs/SVOCs is then
directed to two parallel detectors at a flow
rate of 2 cm3/min each. The detectors sense
the presence of the speciated VOCs/SVOCs, and
the response is recorded by either a strip
chart recorder or a data processing unit.
10.1.3.2 Typical chromatograms of VOCs determined by
the 6C-FID-ECD analytical system are illus-
trated in Figures ll(c) and ll(d), respectively.
10.1.3.3 Helium is used as the carrier gas (4 cm3/min)
to purge residual air from the trap at the
end of the sampling phase and to carry the
revolatilized VOCs through the Megabore®
GC column. Moisture and organic impurities
are removed from the helium gas stream by a
chemical purifier installed in the GC (see
-------
T014-30
Section 7.2.1.11). After exiting the OV-1 -
Megabore® column, the carrier gas stream is
split to the two detectors at rates of 2
cm3/min each.
10.1.3.4 Gas scrubbers containing Drierite® or silica
gel and 5A molecular sieve are used to remove
moisture and organic impurities from the zero
air, hydrogen, and nitrogen gas streams. [Note:
Purity of gas purifiers is checked prior to use
by passing humid zero-air through the gas purifier
and analyzing according to Section 12.2.2.] ,
10.1.3.5 All lines should be kept as short as practical. '
All tubing used for the system should be chro-
matographic grade stainless steel connected
with stainless steel fittings. After assembly,
the system should be checked for leaks accord-
ing to manufacturer's specifications.
10.1.3.6 The FID burner air, hydrogen, nitrogen (make-
up), and helium (carrier) flow rates should
be set according to the manufacturer's instruc-
tions to obtain an optimal FID response while
maintaining a stable flame throughout the analy-
sis. Typical flow rates are: burner air, 450
cm3/min; hydrogen, 30 cm3/min; nitrogen, 30
cm3/min; helium, 2 cm3/min.
10.1.3.7 The ECD nitrogen make-up gas and helium carrier
flow rates should be set according to manufac-
turer's instructions to obtain an optimal ECD
response. Typical flow rates are: nitrogen,
76 cm3/min and helium, 2 cm3/min.
10.1.3.8 The GC-FID-ECD could be modified to include a
PID (see Figure 6) for increased sensitivity
(20). In the photoionization process, a mole-
cule is ionized by ultraviolet light as follows:
R + hv --> R + e-, where R+ is the ionized species
and a photon is represented by hv, with energy
less than or equal to the ionization potential of
-------
T014-31
the molecule. Generally all species with an
ionization potential less than the ionization
energy of the lamp are detected. Because the
ionization potential of all major components
of air (02, N2, CO, C02, and H20) is greater
than the ionization energy of lamps in general
use, they are not detected. The sensor is
comprised of an argon-filled, ultraviolet (UV)
light source where a portion of the organic
vapors are ionized in the gas stream. A pair
of electrodes are contained in a chamber adja-
cent to the sensor. When a positive potential
is applied to the electrodes, any ions formed
by the absorption of UV light are driven by
the created electronic field to the cathode,
and the current (proportional to the organic
vapor concentration) is measured. The PlD
is generally used for compounds having ioni-
zation potentials less than the ratings of
the ultraviolet lamps. This detector is
used for determination of most chlorinated
and oxygenated hydrocarbons, aromatic
compounds, and high molecular weight aliphatic
compounds. Because the PID is insensitive
to methane, ethane, carbon monoxide, carbon
dioxide, and water vapor, it is an excellent
detector. The electron volt rating is applied
specifically to the wavelength of the most
intense emission line of the lamp's output
spectrum. Some compounds with ionization
potentials above the lamp rating can still
be detected due to the presence of small
quantities of more intense light. A typical
system configuration associated with the
GC-FID-ECD-PID is illustrated in Figure 6.
This system is currently being used in EPA's
FY-88 Urban Air Toxics Monitoring Program.
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10.2 GC-MS-SCAN-SIM System Performance Criteria
10.2.1 GC-MS System Operation
10.2.1.1 Prior to analysis, the GC-MS system is assembled
and checked according to manufacturer's instruc-
tions.
10.2.1.2 Table 3.0 outlines general operating conditions
for the GC-MS-SCAN-SIM system with optional FID.
10.2.1.3 The GC-MS system is first challenged with humid
zero air (see Section 11.2.2).
10.2.1.4 The GC-MS and optional FID system is acceptable
if it contains less than 0.2 ppbv of targeted
VOCs.
10.2.2 Daily GC-MS Tuning (See Figure 13)
10.2.2.1 At the beginning of each day or prior to a
calibration, the GC-MS system must be tuned to
verify that acceptable performance criteria are
achieved.
10.2.2.2 For tuning the GC-MS, a cylinder containing
4-bromofluorobenzene is introduced via a
sample loop valve injection system. [Note:
Some systems allow auto-tuning to facilitate
this process.] The key ions and ion abundance
criteria that must be met are illustrated in
Table 4. Analysis should not begin until
all those criteria are met.
10.2.2.3 The GC-MS tuning standard could also be used to
assess GC column performance (chromatographic
check) and as an internal standard. Obtain a
background correction mass spectra of 4-bromo-
fluorobenzene and check that all key ions cri-
teria are met. If the criteria are not achieved,
the analyst must retune the mass spectrometer and
repeat the test until all criteria are achieved.
10.2.2.4 The performance criteria must be achieved before
any samples, blanks or standards are analyzed. If
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any key ion abundance observed for the daily 4-
bromofluorobenzene mass tuning check differs by
more than 10% absolute abundance from that observed
during the previous daily tuning, the instrument
must be retuned or the sample and/or calibration
gases reanalyzed until the above condition is met.
10.2.3 GC-MS Calibration (See Figure 13)
[Note: Initial and routine calibration procedures are
illustrated in Figure 13.]
10.2.3.1 Initial Calibration - Initially, a multipoint dy-
namic calibration (three levels plus humid zero
air) is performed on the GC-MS system, before
sample analysis, with the assistance of a calibra-
tion system (see Figure 8). The calibration sys-
tem uses NBS traceable standards or NBS/EPA CRMs
in pressurized cylinders [containing a mixture
of the targeted VOCs at nominal concentrations of
10 ppmv in nitrogen (Section 8.2)] as working
standards to be diluted with humid zero air. The
contents of the working standard cylinder(s) are
metered (2 cm3/min) into the heated mixing chamber
where they are mixed with a 2-L/min humidified
zero air gas stream to achieve a nominal 10 ppbv
per compound calibration mixture (see Figure 8).
This nominal 10 ppbv standard mixture is allowed
to flow and equilibrate for a minimum of 30 min-
utes. After the equilibration period, the gas
standard mixture is sampled and analyzed by the
real-time GC-MS system [see Figure 8(a) and Sec-
tion 7.2.1]. The results of the analyses are
averaged, flow audits are performed on the mass
flow meters and the calculated concentration com-
pared to generated values. After the GC-MS is
calibrated at three concentration levels, a second
humid zero air sample is passed through the system
and analyzed. The second humid zero air test is
used to verify that the GC-MS system is certified
clean (less than 0.2 ppbv of target compounds).
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10.2.3.2 As an alternative, a multipoint humid static
calibration (three levels plus zero humid air)
can be performed on the GC-MS system. During
the humid static calibration analyses, three
(3) SUMMA® passivated canisters are filled
each at a different concentration between 1-20
ppbv from the calibration manifold using a
pump and mass flow control arrangement [see
Figure 8(c)]. The canisters are then delivered
to the GC-MS to serve as calibration standards.
The canisters are analyzed by the MS in the
SIM mode, each analyzed twice. The expected
retention time and ion abundance (see Table
2 and Table 5) are used to verify proper opera-
tion of the GC-MS system. A calibration re-
sponse factor is determined for each analyte,
as illustrated in Table 5, and the computer
calibration table is updated with this infor-
mation, as illustrated in Table 6.
10.2.3.3 Routine Calibration - The GC-MS system is cal-
ibrated daily (and before sample analysis) with
a one-point calibration. The GC-MS system is
calibrated either with the dynamic calibration
procedure [see Figure 8(a)] or with a 6-L SUMMA®
passivated canister filled with humid calibration
standards from the calibration manifold (see
Section 10.2.3.2). After the single point cali-
bration, the GC-MS analytical system is challenged
with a humidified zero gas stream to insure the
analytical system returns to specification (less
than 0.2 ppbv of selective organics).
ID.3 GC-FID-ECD System Performance Criteria (With Optional PID System)
(See Figure 14)
10.3.1 Humid Zero Air Certification
10.3.1.1 Before system calibration and sample analysis,
the GC-FID-ECD analytical system is assembled and
checked according to manufacturer's instructions.
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10.3.1.2 The 6C-FID-ECD system is first challenged with
humid zero air (see Section 12.2.2) and moni-
tored.
10.3.1.3 Analytical systems contaminated with less than
0.2 ppbv of targeted VOCs are acceptable.
10.3.2 GC Retention Time Windows Determination (See Table 7)
10.3.2.1 Before analysis can be performed, the retention
time windows must be established for each
analyte.
10.3.2.2 Make sure the GC system is within optimum
operating conditions.
10.3.2.3 Make three injections of the standard contain-
ing all compounds for retention time window
determination. [Note: The retention time
window must be established for each analyte
every 72 hours during continuous operation.]
10.3.2.4 Calculate the standard deviation of the three
absolute retention times for each single com-
ponent standard. The retention window is
defined as the mean plus or minus three times
the standard deviation of the individual reten-
tion times for each standard. In those cases
where the standard deviation for a particular
standard is zero, the laboratory must substi-
tute the standard deviation of a closely-
eluting, similar compound to develop a valid
retention time window.
10.3.2.5 The laboratory must calculate retention time
windows for each standard (see Table 7) on
each GC column, whenever a new GC column is
installed or when major components of the GC
are changed. The data must be noted and re-
tained in a notebook by the laboratory as
part of the user SOP and as a quality assurance
check of the analytical system.
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10.3.3 GC Calibration
[Note: Initial and routine calibration procedures are
illustrated in Figure 14.]
10.3.3.1 Initial Calibration - Initially, a multipoint
dynamic calibration (three levels plus humid
zero air) is performed on the 6C-FID-ECD sys-
tem, before sample analysis, with the assist-
ance of a calibration system (see Figure 8).
The calibration system uses NBS traceable
standards or NBS/EPA CRMs in pressurized
cylinders [containing a mixture of the
targeted VOCs at nominal concentrations of
10 ppmv in nitrogen (Section 8.2)] as working
standards to be diluted with humid zero air.
The contents of the working standard cylinders
are metered (2 cm3/min) into the heated
mixing chamber where they are mixed with a
2-L/min humidified zero air stream to achieve
a nominal 10 ppbv per compound calibration
mixture (see Figure 8). This nominal 10
ppbv standard mixture is allowed to flow and
equilibrate for an appropriate amount of
time. After the equilibration period, the gas
standard mixture is sampled and analyzed by
the GC-MS system [see Figure 8(a)]. The
results of the analyses are averaged, flow
audits are performed on the mass flow control-
lers used to generate the standards and the
appropriate response factors (concentration/
area counts) are calculated for each compound,
as illustrated in Table 5. [Note: GC-FIDs
are linear in the 1-20 ppbv range and may
not require repeated multipoint calibra-
tions; whereas, the GC-ECD will require
frequent linearity evaluation.] Table 5 out-
lines typical calibration response factors
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T014-37
and retention times for 40 VOCs. After the
GC-FID-ECD is calibrated at the three concen-
tration levels, a second humid zero air sample
is passed through the system and-analyzed. The
second humid zero air test is used to verify
that the GC-FID-ECD system is certified clean
(less than 0.2 ppbv of target compounds).
10.3.3.2 Routine Calibration - A one point calibration
is performed daily on the analytical system to
verify the initial multipoint calibration (see
Section 10.3.3.1). The analyzers (GC-FID-ECD)
are calibrated (before sample analysis) using
the static calibration procedures (see Section
10.2.3.2) involving pressurized gas cylinders
containing low concentrations of the targeted
VOCs (10 ppbv) in nitrogen. After calibration,
humid zero air is once again passed through the
analytical system to verify residual VOCs are
not present.
10.3.4 GC-FID-ECD-PID System Performance Criteria
10.3.4.1 As an option, the user may wish to include a
photoionization detector (PID) to assist in
peak identification and increase sensitivity.
10.3.4.2 This analytical system is presently being used
in U.S. Environmental Protection Agency's Urban
Air Toxic Pollutant Program (UATP).
10.3.4.3 Preparation of the GC-FID-ECD-PID analytical
system is identical to the GC-FID-ECD system
(see Section 10.3).
10.3.4.4 Table 8 outlines typical retention times (minutes)
for selected organics using the GC-FID-ECD-PID
analytical system.
10.4 Analytical Procedures
10.4.1 Canister Receipt
10.4.1.1 The overall condition of each sample canister
is observed. Each canister should be received
with an attached sample identification tag.
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10.4.1.2 Each canister is recorded in the dedicated
laboratory logbook. Also noted on the identi-
fication tag are date received and initials
of recipient.
10.4.1.3 The pressure of the canister is checked by
attaching a pressure gauge to the canister
inlet. The canister valve is opened briefly
and the pressure (kPa, psig) is recorded.
[Note: If pressure is <83 kPa (<12 psig), the
user may wish to pressurize the canisters,
as an option, with zero grade nitrogen up to
137 kPa (20 psig) to ensure that enough
sample is available for analysis. However,
pressurizing the canister can introduce addi-
tional error, increase the minimum detection
limit (MDL), and is time consuming. The user
should weigh these limitations as part of his
program objectives before pressurizing.]
Final cylinder pressure is recorded on can-
ister sampling field data sheet (see Figure 10)
10.4.1.4 If the canister pressure is increased, a di-
lution factor (DF) is calculated and recorded
on the sampling data sheet.
DF = Ya_
where:
Xa = canister pressure (kPa, psia) abso-
lute before dilution.
Ya = canister pressure (kPa, psia) abso-
lute after dilution.
After sample analysis, detected VOC concentra-
tions are multiplied by the dilution factor
to determine concentration in the sampled air.
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TO14-39
10.4.2 GC-MS-SCAN Analysis (With Optional FID System)
10.4.2.1 The analytical system should be properly assem-
bled, humid zero air certified (see Section
12.3), operated (see Table 3), and calibrated
for accurate VOC determination.
10.4.2.2 The mass flow controllers are checked and adjusted
to provide correct flow rates for the system.
10.4.2.3 The sample canister is connected to the inlet
of the GC-MS-SCAN (with optional FID) analytical
system. For pressurized samples, a mass flow
controller is placed on the canister and the
canister valve is opened and the canister
flow is vented past a tee inlet to the analytical
system at a flow of 75 cm3/min so that 40
cm3/min is pulled through the Nafion® dryer to
the six-port chromatographic valve. [Note: Flow
rate is not as important as acquiring sufficient
sample volume.] Sub-ambient pressure samples are
connected directly to the inlet.
10.4.2.4 The GC oven and cryogenic trap (inject position)
are cooled to their set points of -50°C and
-160°C, respectively.
10.4.2.5 As soon as the cryogenic trap reaches its lower
set point of -160°C, the six-port chromatographic
valve is turned to its fill position to initiate
sample collection.
10.4.2.6 A ten minute collection period of canister sample
is utilized. [Note: 40 cm3/min x 10 min = 400
cm3 sampled canister contents.]
10.4.2.7 After the sample is preconcentrated in the cry-
ogenic trap, the GC sampling valve is cycled
to the inject position and the cryogenic trap
is heated. The trapped analytes are thermally
desorbed onto the head of the OV-1 capillary
column (0.31 mm I.D. x 50 m length). The GC
oven is programmed to start at -50°C and after
2 min to heat to 150°C at a rate of 8°C per
minute.
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T014-40
10.4.2.8 Upon sample injection onto the column, the MS
is signaled by the computer to scan the eluting
carrier gas from 18 to 250 amu, resulting in a
1.5 Hz repetition rate. This corresponds to
about 6 scans per eluting chromatographic peak.
10.4.2.9 Primary identification is based upon retention
time and relative abundance of eluting ions
as compared to the spectral library stored on
the hard disk of the 6C-MS data computer.
10.4.2.10 The concentration (ppbv) is calculated using
the previously established response factors
(see Section 10.2.3.2), as illustrated in
Table 5. [Note: If the canister is diluted
before analysis, an appropriate multiplier is
applied to correct for the volume dilution of
the canister (Section 10.4.1.4).]
10.4.2.11 The optional FID trace allows the analyst to
record the progress of the analysis.
10.4.3 GC-MS-SIM Analysis (With Optional FID System)
10.4.3.1 When the MS is placed in the SIM mode of
operation, the MS monitors only preselected
ions, rather than scanning all masses contin-
uously between two mass limits.
10.4.3.2 As a result, increased sensitivity and improved
quantitative analysis can be achieved.
10.4.3.3 Similar to the GC-MS-SCAN configuration, the
GC-MS-SIM analysis is based on a combination
of retention times and relative abundances of
selected ions (see Table 2 and Table 5). These
qualifiers are stored on the hard disk of
the GC-MS computer and are applied for identi-
fication of each chromatographic peak. Once
the GC-MS-SIM has identified the peak, a calibra-
tion response factor is used to determine the
analyte's concentration.
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T014-41
10.4.3.4 The individual analyses are handled in three
phases: data acquisition, data reduction, and
data reporting. The data acquisition software
is set in the SIM mode, where specific compound
fragments are monitored by the MS at specific
times in the analytical run. Data reduction
is coordinated by the postprocessing macro pro-
gram that is automatically accessed after data
acquisition is completed at the end of the GC
run. Resulting ion profiles are extracted, peaks
are identified and integrated, and an internal
integration report is generated by the program.
A reconstructed ion chromatogram for hardcopy
reference is prepared by the program and various
parameters of interest such as time, date, and
integration constants are printed. At the com-
pletion of the macro program, the data reporting
software is accessed. The appropriate calibra-
tion table (see Table 9) is retrieved by the
data reporting program from the computer's hard
disk storage and the proper retention time and
response factor parameters are applied to the
macro program's integration file. With refer-
ence to certain pre-set acceptance criteria,
peaks are automatically identified and quanti-
fied and a final summary report is prepared,
as illustrated in Table 10.
10.4.4 GC-FID-ECD Analysis (With Optional PID System)
10.4.4.1 The analytical system should be properly assem-
bled, humid zero air certified (see Section 12.2)
and calibrated through a dynamic standard cali-
bration procedure (see Section 10.3.2). The
FID detector is lit and allowed to stabilize.
10.4.4.2 Sixty-four minutes are required for each sample
analysis - 15 min for system initialization, 14
min for sample collection, 30 min for analysis,
and 5 min for post-time, during which a report
is printed. [Note: This may vary depending
upon system configuration and programming.]
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T014-42
10.4.4.3 The helium and sample mass flow controllers are
checked and adjusted to provide correct flow
rates for the system. Helium is used to purge
residual air from the trap at the end of the
sampling phase and to carry the revolatilized
VOCs from the trap onto the GC column and into
the FID-ECD. The hydrogen, burner air, and ni-
trogen flow rates should also be checked. The
cryogenic trap is connected and verified to
be operating properly while flowing cryogen
through the system.
10.4.4.4 The sample canister is connected to the inlet of
the GC-FID-ECD analytical system. The canister
valve is opened and the canister flow is vented
past a tee inlet to the analytical system at 75
cm3/min using a 0-500 cm3/min Tylan mass flow
controller. During analysis, 40 cm3/min of sample
gas is pulled through the six-port chromatographic
valve and routed through the trap at the appro-
priate time while the extra sample is vented.
The VOCs are condensed in the trap while the
excess flow is exhausted through an exhaust
vent, which assures that the sample air flow-
ing through the trap is at atmospheric pressure.
10.4.4.5 The six-port valve is switched to the inject
position and the canister valve is closed.
10.4.4.6 The electronic integrator is started.
10.4.4.7 After the sample is preconcentrated on the trap,
the trap is heated and the VOCs are thermally
desorbed onto the head of the capillary column.
Since the column is at -50°C, the VOCs are cryo-
focussed on the column. Then, the oven tempera-
ture (programmed) increases and the VOCs elute
from the column to the parallel FID-ECD assembly.
10.4.4.8 The peaks eluting from the detectors are iden-
tified by retention time (see Table 7 and
Table 8), while peak areas are recorded in area
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T014-43
counts. Figures 15 and 16 illustrate typical
response of the FID and ECD, respectively,
for the forty (40) targeted VOCs.. [Note: Refer
to Table 7 for peak number and identification.]
10.4.4.9 The response factors (see Section 10.3.3.1) are
multiplied by the area counts for each peak
to calculate ppbv estimates for the unknown
sample. If the canister is diluted before
analysis, an appropriate dilution multiplier
(DF) is applied to correct for the volume dilu-
tion of the canister (see Section 10.4.1.4).
10.4.4.10 Depending on the number of canisters to be
analyzed, each canister is analyzed twice
and the final concentrations for each analyte
are the averages of the two analyses.
10.4.4.11 However, if the GC-FID-ECD analytical system
discovers unexpected peaks which need further
identification and attention or overlapping
peaks are discovered, eliminating possible quan-
titation, the sample should then be subjected
to a GC-MS-SCAN for positive identification
and quantitation.
11. Cleaning and Certification Program
11.1 Canister Cleaning and Certification
11.1.1 All canisters must be clean and free of any contaminants
before sample collection.
11.1.2 All canisters are leak tested by pressurizing them to
approximately 206 kPa (30 psig) with zero air. [Note:
The canister cleaning system in Figure 7 can be used
for this task.] The initial pressure is measured, the
canister valve is closed, and the final pressure is
checked after 24 hours. If leak tight, the pressure
should not vary more than +_ 13.8 kPa (± 2 psig) over
the 24 hour period.
11.1.3 A canister cleaning system may be assembled as illus-
trated in Figure 7. Cryogen is added to both the
vacuum pump and zero air supply traps. The rani
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T014-44
are connected to the manifold. The vent shut-off valve
and the canister valve(s) are opened to release any re-
maining pressure in the canister(s). The vacuum pump
is started and the vent shut-off valve is then closed
and the vacuum shut-off valve is opened. The canister(s)
are evacuated to < 0.05 mm Hg (for at least one hour).
[Note: On a daily basis or more often if necessary, the
cryogenic traps should be purged with zero air to remove
any trapped water from previous canister cleaning cycles.]
11.1.4 The vacuum and vacuum/pressure gauge shut-off valves
are closed and the zero air shut-off valve is opened
to pressurize the canister(s) with humid zero air to
approximately 206 kPa (30 psig). If a zero gas gener-
ator system is used, the flow rate may need to be
limited to maintain the zero air quality.
11.1.5 The zero shut-off valve is closed and the canister(s)
is allowed to vent down to atmospheric pressure through
the vent shut-off valve. The vent shut-off valve is
closed. Steps 11.1.3 through 11.1.5 are repeated two
additional times for a total of three (3) evacuation/
pressurization cycles for each set of canisters.
11.1.6 At the end of the evacuation/pressurization cycle, the
canister is pressurized to 206 kPa (30 psig) with
humid zero air. The canister is then analyzed by a
GC-MS or GC-FID-ECD analytical system. Any canister
that has not tested clean (compared to direct analysis
of humidified zero air of less than 0.2 ppbv of targeted
VOCs) should not be used. As a "blank" check of the
canister(s) and cleanup procedure, the final humid zero
air fill of 100% of the canisters is analyzed until the
cleanup system and canisters are proven reliable (less
than 0.2 ppbv of targets VOCs). The check can then be
reduced to a lower percentage of canisters.
11.1.7 The canister is reattached to the cleaning manifold and
is then reevacuated to <0.05 mm Hg and remains in this
condition until used. The canister valve is closed. The
canister is removed from the cleaning system and the can-
ister connection is capped with a stainless steel fitting.
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T014-45
The canister is now ready for collection of an air sample.
An identification tag is attached to the neck of each
canister for field notes, and chain-of-custody purposes.
11.1.8 As an option to the humid zero air cleaning procedures,
the canisters could be heated in an isothermal oven to
100°C during Section 11.1.3 to ensure that lower mole-
cular weight compounds (C2-Cs) are not retained on the
walls of the canister. [Note: For sampling heavier, more
complex VOC mixtures, the canisters should be heated to
250°C during Section 11.1.3.7.] Once heated, the canisters
are evacuated to 0.05 mm Hg. At the end of the heated/
evacuated cycle, the canisters are pressurized with humid
zero air and analyzed by the GC-FID-ECD system. Any
canister that has not tested clean (less than 0.2 ppbv
of targeted compounds) should not be used. Once
tested clean, the canisters are reevacuated to 0.05 mm
Hg and remain in the evacuated state until used.
11.2 Sampling System Cleaning and Certification
11.2.1 Cleaning Sampling System Components
11.2.1.1 Sample components are disassembled and cleaned
before the sampler is assembled. Nonmetallic
parts are rinsed with HPLC grade deionized
water and dried in a vacuum oven at 50°C.
Typically, stainless steel parts and fittings
are cleaned by placing them in a beaker of
methanol in an ultrasonic bath for 15 minutes.
This procedure is repeated with hexane as
the solvent.
11.2.1.2 The parts are then rinsed with HPLC grade
deionized water and dried in a vacuum oven
at 100°C for 12 to 24 hours.
11.2.1.3 Once the sampler is assembled, the entire
system is purged with humid zero air for 24
hours.
11.2.2 Humid Zero Air Certification
[Note: In the following sections, "certification" is
defined as evaluating the sampling system with humid
-------
puts AHoiasa . . ,
K ' jeded pepAoaj
T014-46
zero air and humid calibration gases that pass through
all active components of the sampling system. The sys-
tem is "certified" if no significant additions or dele-
tions (less than 0.2 ppbv of targeted compounds) have
occurred when challenged with the test gas stream.]
11.2.2.1 The cleanliness of the sampling system is deter-
mined by testing the sampler with humid zero air
without an evacuated gas cylinder, as follows.
11.2.2.2 The calibration system and manifold are assem-
bled, as illustrated in Figure 8. The sampler
(without an evacuated gas cylinder) is con-
nected to the manifold and the zero air
cylinder activated to generate a humid gas
stream (2 L/min) to the calibration manifold
[see Figure 8(b)].
11.2.2.3 The humid zero gas stream passes through the
calibration manifold, through the sampling
system (without an evacuated canister) to a
6C-FID-ECD analytical system at 75 cm3/min
so that 40 crrrVmin is pulled through the six-
port valve and routed through the cryogenic
trap (see Section 10.2.2.1) at the appropriate
time while the extra sample is vented. [Note:
The exit of the sampling system (without the
canister) replaces the canister in Figure 4.]
After the sample (400 ml) is preconcentrated
on the.trap, the trap is heated and the VOCs
are thermally desorbed onto the head of the
capillary column. Since the column is at
-50°C, the VOCs are cryofocussed on the col-
umn. Then, the oven temperature (programmed)
increases and the VOCs begin to elute and are
detected by a GC-MS (see Section 10.2) or the
GC-FID-ECD (see Section 10.3). The analytical
system should not detect greater than 0.2 ppbv
of targeted VOCs in order for the sampling
system to pass the humid zero air certification
-------
T014-47
test. Chromatograms of a certified sampler
and contaminated sampler are illustrated in
Figures 17(a) and (b), respectively. If
the sampler passes the humid zero air test,
it is then tested with humid calibration gas
standards containing selected VOCs at concen-
tration levels expected in field sampling (e.g.,
0.5 to 2 ppbv) as outlined in Section 11.2.3.
11.2.3 Sampler System Certification with Humid Calibration Gas
Standards
11.2.3.1 Assemble the dynamic calibration system and
manifold as illustrated in Figure 8.
11.2.3.2 Verify that the calibration system is clean
(less than 0.2 ppbv of targeted compounds)
by sampling a humidified gas stream, without
gas calibration standards, with a previously
certified clean canister (see Section 12.1).
11.2.3.3 The assembled dynamic calibration system is
certified clean if less than 0.2 ppbv of
targeted compounds are found.
11.2.3.4 For generating the humidified calibration
standards, the calibration gas cylinder(s)
(see Section 8.2) containing nomin*! concen-
trations of 10 ppmv in nitrogen of S'lected
VOCs, are attached to the calibration system, as
outlined in Section 10.2.3.1. The gas cylinders
are opened and the gas mixtures are passed
through 0 to 10 cm3/min certified mass flow
controllers to generate ppb levels of
calibration standards.
11.2.3.5 After the appropriate equilibrium period, attach
the sampling system (containing a certified
evacuated canister) to the manifold, as illus-
trated in Figure 8(a).
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T014-48
11.2.3.6 Sample? the dynamic calibration gas stream with
the sampling system according to Section 9.2.1.
[Note: To conserve generated calibration gas,
bypass the canister sampling system manifold
and attach the sampling system to the calibra-
tion gas stream at the inlet of the in-line
filter of the sampling system so the flow
will be less than 500 cm3/min.]
11.2.3.7 Concurrent with the sampling system operation,
realtime monitoring of the calibration gas
stream is accomplished by the on-line GC-MS
or GC-multidetector analytical system
[Figure 8(b)] to provide reference concentra-
tions of generated VOCs.
11.2.3.8 At the end of the sampling period (normally same
time period used for anticipated sampling),
the sampling system canister is analyzed and
compared to the reference GC-MS or GC-multi-
detector analytical system to determine if
the concentration of the targeted VOCs was
increased or decreased by the sampling
system.
11.2.3.9 A recovery of between 90% and 110% is expected
for all targeted VOCs.
12. Performance Criteria and Quality Assurance
12.1 Standard Operating Procedures (SOPs)
12.1.1 SOPs should be generated in each laboratory describing
and documenting the following activities: (1) assembly,
calibration, leak check, and operation of specific
sampling systems and equipment used; (2) preparation,
storage, shipment, and handling of samples; (3) assembly,
leak-check, calibration, and operation of the analytical
system, addressing the specific equipment used; (4) can-
ister storage and cleaning; and (5) all aspects of data
recording and processing, including lists of computer
hardware and software used.
-------
T014-49
12.1.2 Specific stepwise instructions should be provided in
the SOPs and should be readily available to and under-
stood by the laboratory personnel conducting the work.
12.2 Method Relative Accuracy and Linearity
12.2.1 Accuracy can be determined by injecting VOC standards
(see Section 8.2) from an audit cylinder into a sampler.
The contents are then analyzed for the components con-
tained in the audit canister. Percent relative accuracy
is calculated:
% Relative Accuracy = V - x x 100
X
Where: Y = Concentration of the targeted
compound recovered from sampler.
X = Concentration of VOC targeted
compound in the NBS-SRM or
EPA-CRM audit cylinders.
12.2.2 If the relative accuracy does not fall between 90 and
and 110 percent, the field sampler should be removed
from use, cleaned, and recertified according to initial
certification procedures outlined in Section 11.2.2
and Section 11.2.3. Historically, concentrations of
carbon tetrachloride, tetrachloroethylene, and hexachlo-
robutadiene have sometimes been detected at lower con-
centrations when using parallel ECD and FID detectors.
When these three compounds are present at concentrations
close to calibration levels, both detectors usually
agree on the reported concentrations. At concentrations
below 4 ppbv, there is a problem with nonlinearity of
the ECD. Plots of concentration versus peak area for
calibration compounds detected by the ECD have shown
that the curves are nonlinear for carbon tetrachloride,
tetrachloroethylene, and hexachlorobutadiene, as illus-
trated in Figures 18(a) through 18(c). Other targeted
ECD and FID compounds scaled linearly for the range 0 to
8 ppbv, as shown for chloroform in Figure 18(d). For
compounds that are not linear over the calibration
-------
T014-50
range, area counts generally roll off between 3 and 4
ppbv. To correct for the nonlinearity of these compounds,
an additional calibration step is performed. An evacuated
stainless steel canister is pressurized with calibration
gas at a nominal concentration of 8 ppbv. The sample
is then diluted to approximately 3.5 ppbv with zero air
and analyzed. The instrument response factor (ppbv/area)
of the ECD for each of the three compounds is calculated
for the 3.5 ppbv sample. Then, both the 3.5 ppbv and
the 8 ppbv response factors are entered into the ECD
calibration table. The software for the Hewlett-Packard
5880 level 4 GC is designed to accommodate multilevel
calibration entries, so the correct response factors
are automatically calculated for concentrations in this
range.
12.3 Method Modification
12.3.1 Sampling
12.3.1.1 The sampling system for pressurized canister
sampling could be modified to use a lighter,
more compact pump. The pump currently being
used weighs about 16 kilograms (35 Ibs). Com-
mercially available pumps that could be used
as alternatives to the prescribed sampler pump
are described below. Metal Bellows MB-41 pump:
These pumps are cleaned at the factory; however,
some precaution should be taken with the circu-
lar (4.8 cm diameter) Teflon® and stainless steel
part directly under the flange. It is often
dirty when received and should be cleaned
before use. This part is cleaned by removing
it from the pump, manually cleaning with
deionized water, and placing in a vacuum oven
at 100°C for at least 12 hours. Exposed
parts of the pump head are also cleaned with
swabs and allowed to air dry. These pumps have
-------
T014-51
proven to be very reliable; however, they are
only useful up to an outlet pressure of about
137 kPa (20 psig). Neuberger Pump: Viton gas-
kets or seals must be specified -with this pump.
The "factory direct" pump is received contaminated
and leaky. The pump is cleaned by disassembling
the pump head (which consists of three stainless
steel parts and two gaskets), cleaning the gaskets
with deionized water and drying in a vacuum oven,
and remachining (or manually lapping) the sealing
surfaces of the stainless steel parts. The stain-
less steel parts are then cleaned with methanol,
hexane, deionized water and heated in a vacuum
oven. The cause for most of the problems with
this pump has been scratches on the metal parts
of the pump head. Once this rework procedure is
performed, the pump is considered clean and can
be used up to about 240 kPa (35 psig) output pres-
sure. This pump is utilized in the sampling sys-
tem illustrated in Figure 3.
12.3.1.2 Urban Air Toxics Sampler
The sampling system described in this method can
be modified like the sampler in EPA's FY-88 Urban
Air Toxics Pollutant Program. This particular
sampler is described in Appendix C (see Figure 19).
12.3.2 Analysis
12.3.2.1 Inlet tubing from the calibration manifold could
be heated to 50°C (same temperature as the cali-
bration manifold) to prevent condensation on the
internal walls of the system.
12.3.2.2 The analytical strategy for Method TO-14 involves
positive identification and quantitation by
GC-MS-SCAN-SIM mode of operation with optional
FID. This is a highly specific and sensitive
detection technique. Because a specific detec-
tor system (GC-MS-SCAN-SIM) is more complicated
and expensive than the use of non-specific detectors
-------
T014-52
(GC-FID-ECD-PID), the analyst may want to perform
a screening analysis and preliminary quantisation
of VOC species in the sample, including any polar
compounds, by utilizing the GC-multidetector
(GC-FID-ECD-PID) analytical system prior to GC-MS
analysis. This system can be used for approximate
quantitation. The GC-FID-ECD-PID provides a "snap-
shot" of the constituents in the sample, allow-
ing the analyst to determine:
- Extent of misidentification due to over-
lapping peaks,
- Whether the constituents are within the
calibration range of the anticipated
GC-MS-SCAN-SIM analysis or does the
sample require further dilution, and
- Are there unexpected peaks which need further
identification through GC-MS-SCAN or are
there peaks of interest needing attention?
If unusual peaks are observed from the GC-FID-ECD-
PID system, the analyst then performs a GC-MS-SCAN
analysis. The GC-MS-SCAN will provide positive
identification of suspect peaks from the GC-FID-
ECD-PID system. If no unusual peaks are identi-
fied and only a select number of VOCs are of con-
cern, the analyst can then proceed to GC-MS-SIM.
The GC-MS-SIM is used for final quantitation of
selected VOCs. Polar compounds, however, cannot
be identified by the GC-MS-SIM due to the use
of a Nafion® dryer to remove water from the sample
prior to analysis. The dryer removes polar com-
pounds along with the water. The analyst often
has to make this decision incorporating project
objectives, detection limits, equipment availa-
bility, cost and personnel capability in develop-
ing an analytical strategy. Figure 20 outlines
the use of the GC-FID-ECD-PID as a "screening"
approach, with the GC-MS-SCAN-SIM for final
identification and quantitation.
-------
T014-53
12.4 Method Safety
This procedure may involve hazardous materials, operations, and
equipment. This method does not purport to address all of the
safety problems associated with its use. It is the user's respon-
sibility to establish appropriate safety and health practices
and determine the applicability of regulatory limitations prior
to the implementation of this procedure. This should be part
of the user's SOP manual.
12.5 Quality Assurance (See Figure 21)
12.5.1 Sampling System
12.5.1.1 Section 9.2 suggests that a portable GC system be
used as a "screening analysis" prior to locating
fixed-site samplers (pressurized or subatmospheric),
12.5.1.2 Section 9.2 requires pre and post-sampling meas-
urements with a certified mass flow controller
for flow verification of sampling system.
12.5.1.3 Section 11.1 requires all canisters to be pres-
sure tested to 207 kPa _+ 14 kPa (30 psig ± 2 psig)
over a period of 24 hours.
12.5.1.4 Section 11.1 requires that all canisters be
certified clean (containing less than 0.2 ppbv
of targeted VOCs) through a humid zero air certi-
fication program.
12.5.1.5 Section 11.2.2 requires all field sampling systems
to be certified initially clean (containing less
than 0.2 ppbv of targeted VOCs) through a humid
zero air certification program.
12.5.1.6 Section 11.2.3 requires all field sampling sys-
tems to pass an initial humidified calibration
gas certification [at VOC concentration levels
expected in the field (e.g., 0.5 to 2 ppbv)]
with a percent recovery of greater than 90.
12.5.2 GC-MS-SCAN-SIM System Performance Criteria
12.5.2.1 Section 10.2.1 requires the GC-MS analytical
system to be certified clean (less than 0.2
-------
T014-54
ppbv of targeted VOCs) prior to sample analy-
sis, through a humid zero air certification.
12.5.2.2 Section 10.2.2 requires the daily tuning of
the GC-MS with 4-bromofluorobenzene (4-BFB)
and that it meet the key ions and ion abun-
dance critera (10%) outlined in Table 5.
12.5.2.3 Section 10.2.3 requires both an initial multi-
point humid static calibration (three levels
plus humid zero air) and a daily calibration
(one point) of the GC-MS analytical system.
12.5.3 GC-Multidetector System Performance Criteria
12.5.3.1 Section 10.3.1 requires the GC-FID-ECD analyti-
cal system, prior to analysis, to be certified
clean (less than 0.2 ppbv of targeted VOCs)
through a humid zero air certification.
12.5.3.2 Section 10.3.2 requires that the GC-FID-ECD
analytical system establish retention time
windows for each analyte prior to sample analy-
sis, when a new GC column is installed, or
major components of the GC system altered
since the previous determination.
12.5.3.3 Section 8.2 requires that all calibration
gases be traceable to a National Bureau of
Standards (NBS) Standard Reference Material
(SRM) or to a NBS/EPA approved Certified
Reference Material (CRM).
12.5.3.4 Section 10.3.2 requires that the retention
time window be established throughout the
course of a 72-hr analytical period.
12.5.3.5 Section 10.3.3 requires both an initial multi-
point calibration (three levels plus humid
zero air) and a daily calibration (one point)
of the GC-FID-ECD analytical system with zero
gas dilution of NBS traceable or NBS/EPA CRMs
gases. [Note: Gas cylinders of VOCs at the
ppm and ppb level are available for audits
from the USEPA, Environmental Monitoring Systems
-------
T014-55
Laboratory, Quality Assurance Division, MD-77B,
Research Triangle Park, NC 27711, (919)541-4531.
Appendix A outlines five groups of audit gas
cylinders available from USEPA.]
13. Acknowledgements
The determination of volatile and some semi-volatile organic compounds
in ambient air is a complex task, primarily because of the wide variety
of compounds of interest and the lack of standardized sampling and
analytical procedures. While there are numerous procedures for sampling
and analyzing VOCs/SVOCs in ambient air, this method draws upon the
best aspects of each one and combines them into a standardized method-
ology. To that end, the following individuals contributed to the
research, documentation and peer review of this manuscript.
-------
Topic
Sampling System
Analytical System
GC-FID-ECD
Contact
Mr. Frank McElroy
Mr. Vinee Thompson
Dr. Bill McClenny
Mr. Joachim Pleil
Mr. Tom Merrifield
Mr. Joseph P. Krasnec
Dr. Bill McClenny
Mr. Joachim Pleil
Ms. Karen D. Oliver
GC-FID-ECD-PID Dave-Paul Dayton
JoAnn Rice
Address
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-77
Research Triangle Park, N.C. 27711
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-44
Research Triangle Park, N.C. 27711
Anderson Samplers, Inc.
4215-C Wendell Drive
Atlanta, GA 30336
Scientific Instrumentation Specialists, Inc.
P.O. Box 8941
Moscow, Idaho, 83843
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-44
Research Triangle Park, N.C. 27711
Northrop Services, Inc.
Environmental Sciences
P.O. Box 12313
Research Triangle Park, N.C. 27709
Radian Corporation
P.O. Box 13000
Progress Center
Research Triangle Park, N.C. 27709
Telephone No.
919-541-2622
919-541-3791
919-541-3158
919-541-4680
1-800-241-6898-
208-882-3860-
919-541-3158
919-541-4680
919-549-0611
919-481-0212
CTV
-------
Topic
GC-MS-SCAN-SIM
Canister Cleaning
Certification and
VOC Canister Storage
Stability
Cryogenic
Sampling
Unit
U.S. EPA
Audit Gas
Standards
Contact
Dr. Bill McClenny
Mr. Joachim Pleil
Mr. John V. Hawkins
Mr. Vince Thompson
Dr. Bill McClenny
Mr. Joachim Pleil
Dave-Paul Dayton
JoAnn Rice
Dr. R.K.M. Jayanty
Mr. Lou Ballard
Mr. Pete Watson
Mr. Joachim Pleil
Mr. Bob Lampe
Address
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-44
Research Triangle Park, N.C. 27711
Research Triangle Laboratories, Inc.
P.O. Box 12507
Research Triangle Park, N.C. 27709
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-77
Research Triangle Park, N.C. 27711
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-44
Research Triangle Park, N.C. 27711
Radian Corporation
P.O. Box 13000
Progress Center
Research Triangle Park, N.C. 27709
Research Triangle Institute
P.O. Box 12194
Research Triangle Park, N.C. 27709
NuTech Corporation
2806 Cheek Road
Durham, N.C., 27704
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-44
Research Triangle Park, N.C. 27711
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
MD-77B
Research Triangle Park, N.C.27711
Telephone No.
919-541-3158
919-541-4680
919-544-5775
919-541-3791
919-541-3158
919-541-4680
919-481-0212
919-541-6000
919-682-0402
919-541-4680
919-541-4531
i
en
-------
T014-58
14. REFERENCES
1. K. D. Oliver, J. D. Pleil, and W. A. McClenny, "Sample Integrity of
Trace Level Volatile Organic Compounds in Ambient Air Stored in
SUMMA® Polished Canisters," Atmospheric Environ. 20:1403, 1986.
2. M. W. Holdren and D. L. Smith, "Stability of Volatile Organic Compounds
While Stored in SUMMA® Polished Stainless Steel Canisters," Final
Report, EPA Contract No. 68-02-4127, Research Triangle Park, NC,
Battel le Columbus Laboratories, January, 1986.
3. Ralph M. Riggin, Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds in Ambient Air, EPA-600/4-83-027,
U.S. Environmental Protection Agency, Research Triangle Park, NC, 1983.
4. Ralph M. Riggin, Compendium of Methods for the Determination of Toxic '
Organic Compounds in Ambient Air. EPA-600/4-84-041, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 1986.
5. W. T. Winberry and N. V. Til ley, Supplement to EPA-600/4-84-041;
Compendium of Methods for the Determination of Toxic Organic Compounds
in Ambient Air. EPA-600/4-87-006, U.S. Environmental Protection Agency,
Research Triangle Park, NC, 1986.
6. W. A. McClenny, J. D Pleil, J. W. Holdren, and R. N. Smith, "Automated
Cryogenic Preconcentration and Gas Chromatographic Determination of
Volatile Organic Compounds," Anal. Chem. 56:2947, 1984.
7. J. D. Pleil and K. D. Oliver, "Evaluation of Various Configurations of
Nafion Dryers: Water Removal from Air Samples Prior to Gas Chromatographic
Analysis," EPA Contract No. 68-02-4035, Research Triangle Park, NC,
Northrop Services, Inc.- Environmental Sciences, 1985.
8. K. D. Oliver and J. D. Pleil, "Automated Cryogenic Sampling and Gas
Chromatographic Analysis of Ambient Vapor-Phase Organic Compounds:
Procedures and Comparison Tests," EPA Contract No. 68-02-4035, Research
Triangle Park, NC, Northrop Services, Inc.- Environmental Sciences, 1985.
9. W. A. McClenny and J. D. Pleil, "Automated Calibration and Analysis of
VOCs with a Capillary Column Gas Chromatograph Equipped for Reduced Temper-
ature Trapping," Proceedings of the 1984. Air Pollution Control
Association Annual Meeting, San Francisco, CA, June 24-29, 1984.
10. W. A. McClenny, J. D. Pleil, T. A. Lumpkin, and K. D. Oliver, "Update
on Canister-Based Samplers for VOCs," Proceedings of the 1987 EPA/APCA
Symposium on Measurement of Toxic and Related Air Pollutants, May, 1987
-APCA Publication VIP-8, EPA 600/9-87-010.
11. J. D. Pleil, "Automated Cryogenic Sampling and Gas Chromatographic
Analysis of Ambient Vapor-Phase Organic Compounds: System Design,"
EPA Contract No. 68-02-2566, Research Triangle Park, NC, Northrop
"Services, Inc.- Environmental Sciences, 1982.
-------
T014-59
12. K. D. Oliver and J. D. Pleil, "Analysis of Canister Samples Collected
During the CARB Study in August 1986," EPA Contract No. 68-02-4035,
Research Triangle Park, NC, Northrop Services, Inc.- Environmental
Sciences, 1987.
13. J. D. Pleil and K. D. Oliver, "Measurement of Concentration Variability
of Volatile Organic Compounds in Indoor Air: Automated Operation of a
Sequential Syringe Sampler and Subsequent GC/MS Analysis," EPA Contract
No. 68-02-4444, Research Triangle Park, NC, Northrop Services, Inc. -
Environmental Sciences, 1987.
14. J. F. Walling, "The Utility of Distributed Air Volume Sets When
Sampling Ambient Air Using Solid Adsorbents," Atmospheric Environ.,
18:855-859, 1984.
15. J. F. Walling, J. E. Bumgarner, J. D. Driscoll, C. M. Morris, A. E. Riley,
and L. H. Wright, "Apparent Reaction Products Desorbed From Tenax Used
to Sample Ambient Air," Atmospheric Environ., 20: 51-57, 1986.
16. Portable Instruments User's Manual for Monitoring VOC Sources, EPA-
340/1-88-015, U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Washington, DC, June, 1986.
17. F. F. McElroy, V. L. Thompson, H. G. Richter, A Cryogenic Preconcentra-
tion - Direct FID (PDFID) Method for Measurement of NMOC in the Ambient
Air. EPA-600/4-85-063, U.S. Environmental Protection Agency, Research
Triangle Park, NC, August 1985.
18. R. A. Rasmussen and J. E. Lovelock, "Atmospheric Measurements Using
Canister Technology," J. Geophys. Res., 83: 8369-8378, 1983.
19. R. A. Rasmussen and M.A.K. Khalil, "Atmospheric Halocarbons: Measure-
ments and Analysis of Selected Trace Gases," Proc. NATO ASI on Atmos-
pheric Ozone, BO: 209-231.
20. Dave-Paul Dayton and JoAnn Rice, "Development and Evaluation of a
Prototype Analytical System for Measuring Air Toxics," Final Report,
Radian Corporation for the U.S. Environmental Protection Agency,
Environmental Monitoring Systems Laboratory, Research Triangle Park,
NC 27711, EPA Contract No. 68-02-3889, WA No. 120, November, 1987.
-------
TABLE 1. VOLATILE ORGANIC COMPOUND DATA SHEET
COMPOUND (SYNONYM)
Freon 12 (Dichlorodifluoromethane)
Methyl chloride (Chloromethane)
Freon 114 (l,2-Dichloro-l,l,2,2-
tetrafluoroethane)
Vinyl chloride (Chloroethylene)
Methyl bromide (Bromomethane)
Ethyl chloride (Chloroethane)
Freon 11 (Trichlorof luoromethane)
Vinylidene chloride (1,1-Dichloroethene)
Dichloromethane (Methylene chloride)
Freon 113 (l,l,2-Trichloro-l,2,2-
trifluoroethane)
1,1-Dichloroethane (Ethylidene chloride)
cis-l,2-Dichloroethylene
Chloroform (Trichloromethane)
1,2-Dichloroethane (Ethylene dichloride)
Methyl chloroform (1,1,1-Trichloroethane)
Benzene (Cyclohexatriene)
Carbon tetrachloride (fetrachloromethane)
1,2-Dichloropropane (Propylene
dichloride)
Trichloroethylene (Trichloroethene)
cis-l,3-Dichloropropene (cis-1,3-
dichloropropylene)
FORMULA
C12CF2
CH3C1
C1CF2CC1F2
CH2=CHC1
CHsBr
CH3CH2C1
CClsF
C2H2C12
CH2C12
CF2C1CC12F
CH3CHC12
CHC1=CHC1
CHC13
C1CH2CH2C1
CHsCCla
C6H6
CC14
CH3CHC1CH2C1
C1CH=CC12
CH3CC1=CHC1
MOLECULAR
WEIGHT
120.91
50.49
170.93
62.50
94.94
64.52
137.38
96.95
84.94
187.38
98.96
96.94
119.38
98.96
133.41
78.12
153.82
112.99
131.29
110.97
BOILING
POINT (°C)
-29.8
-24.2
4.1
-13.4
3.6
12.3
23.7
31.7
39.8
47.7
57.3
60.3
61.7
83.5
74.1
80.1
76.5
96.4
87
76
MELTING
POINT (°C)
-158.0
-97.1
-94.0
-1538.0
-93.6
-136.4
-111.0
-122.5
-95.1
-36.4
-97.0
-80.5
-63.5
-35.3
-30.4
5.5
-23.0
-100.4
-73.0
CAS
NUMBER
74-87-3
75-01-4
74-83-9
75-00-3
75-35-4
75-09-2
74-34-3
67-66-3
107-06-2
71-55-6
71-43-2
56-23-5
78-87-5
79-01-6
I
o>
o
-------
TABLE 1. VOLATILE ORGANIC COMPOUND DATA SHEET (cont.)
____ r
COMPOUND (SYNONYM)
trans-l,3-Dichloropropene (cis-1,3-
Dichloropropylene)
1,1,2-Trichloroethane (Vinyl trichloride)
Toluene (Methyl benzene)
1 ,2-Dibremoethane (Ethyl ene di bromide)
Tetrachloroethylene (Perchloroethylene)
Chlorobenzene (Phenyl chloride)
Ethyl benzene
m-Xylene (1,3-Dimethyl benzene)
p-Xylene (1,4-Dimethylxylene)
Styrene (Vinyl benzene)
1,1,2,2-Tetrachloroethane
o-Xylene (1,2-Dimethyl benzene)
1, 3, 5-Tri methyl benzene (Mesitylene)
1, 2, 4-Tri methyl benzene (Pseudocumene)
m-Dichlorobenzene (1,3-Dichlorobenzene)
Benzyl chloride («-Chlorotoluene)
o-Dichlorobenzene (1,2-Dichlorobenzene)
p-Dichlorobenzene (1,4-Dichlorobenzene)
1,2,4-Trichlorobenzene
Hexachi orobut adi ene (1,1,2,3,4,4-
Hexachl oro-1 ,3-but adi ene)
FORMULA
C1CH2CH=CHC1
CH2C1CHC12
C6H5CH3
1,3-^CH3)2C6H4
1,4-(CH3)2C6H4
CHC12CHC12
1,2-(CH3)2C6H4
l,3,5-(CH3)3CeH6
1,2,4-(CH3)3C6H6
1,3-C12C6H4
1,2-C12C6H4
1,4-C12C6H4
l,2,4-Cl3CeH3
MOLECULAR
WEIGHT
110.97
133.41
92.15
187.88
165.83
112.56
mfi 17
106.17
106.17
104.16
167.85
106.17
120.20
120.20
147.01
126.59
147.01
147.01
181.45
BOILING
POINT (°C)
112.0
113.8
110,6
131.3
121.1
132.0
136 2
139.1
138.3
145.2
146.2
144.4
164.7
169.3
173.0
179.3
180.5
174.0
213.5
MELTING
POINT (°C)
-36.5
.... -95.0
9.8
-19.0
-45.6
-95.0
-47.9
13.3
-30.6
-36.0
-25.2
-44.7
-43.8
-24.7
-39.0
-17.0
53.1
17.0
CAS
\NUMBER
79-00-5
108-88-3
106-93-4
127-18-4
108-90-7
100-41-4
100-42-5
79-34-5
108-67-8
95-63-6
541-73-1
100-44-7
95-50-1
106-46-7
120-82-1
o
t—'
f*
I
-------
T014-62
TABLE 2. ION/ABUNDANCE AND EXPECTED RETENTION TIME
FOR SELECTED VOCs ANALYZED BY GC-MS-SIM
Ion/Abundance
Compound (amu/% base peak)
Freon 12 (Dichi orodi fl uoromethane)
Methyl chloride (Chloromethane)
Freon 114 (1, 2-Dichloro-l, 1,2,2-
tetrafluoroethane)
Vinyl chloride (Chloroethene)
Methyl bromide (Bromomethane)
Ethyl chloride (Chl oroethane)
Freon 11 (Trichl orof 1 uoromethane)
Vinylidene chloride (1,1-Dichloroethylene)
Dichloromethane (Methylene chloride)
Freon 113 (l,l,2-Trichloro-l,2,2-
trifluoroethane)
1,1-Dichloroethane (Ethylidene dichloride)
cis-l,2-Dichloroethylene
Chloroform (Trichloromethane)
1,2-Dichloroethane (Ethylene dichloride)
Methyl chloroform (1,1,1-Trichl oroethane)
Benzene (Cyclohexatriene)
Carbon tetrachloride (Tetrachloromethane)
85/100
87/ 31
50/100
52/ 34
85/100
135/ 56
87/ 33
62/100
27/125
64/ 32
94/100
96/ 85
64/100
29/140
27/140
101/100
103/ 67
61/100
96/ 55
63/ 31
49/100
84/ 65
86/ 45
151/100
101/140
103/ 90
63/100
27/ 64
65/ 33
61/100
96/ 60
98/ 44
83/100
85/ 65
47/ 35
62/100
27 / 70
64/ 31
97/100
99/ 64
6 If 61
78/100
77/ 25
50/ 35
117/100
119/ 97
Expected Retention
Time (min)
5.01
5.69
6.55
6.71
7.83
8.43
9.97
10.93
11.21
11.60
12.50
13.40
13.75
14.39
14.62
15.04
15.18
(continued)
-------
TABLE 2.
T014-63
ION/ABUNDANCE AND EXPECTED RETENTION TIME FOR
SELECTED VOCs ANALYZED BY GC-MS-SIM (cont.)
Ion/Abundance
Compound (amu/% base peak)
1,2-Dichloropropane (Propylene dichloride)
Trichloroethylene (Trichloroethene)
cis-l,3-Dichloropropene
trans-l,3-Dichloropropene (1,3
dichloro-1-propene)
1,1,2-Trichl oroethane (Vinyl trichloride)
Toluene (Methyl benzene)
1,2-Dibromoethane (Ethylene dibromide)
Tetrachl oroethylene (Perchloroethylene)
Chlorobenzene (Benzene chloride)
Ethyl benzene
m,p-Xylene(l, 3/1, 4-di methyl benzene)
Styrene (Vinyl benzene)
1 ,1 ,2 ,2-Tetrachl oroethane (Tetrachl oroethane)
o-Xylene (1,2-Dimethylbenzene)
4-Ethyltoluene
1, 3, 5-Tri methyl benzene (Mesitylene)
1,2,4-Trimethylbenzene (Pseudocumene)
m-Dichlorobenzene (1,3-Dichlorobenzene)
63/100
4 1/ 90
62/ 70
130/100
132/ 92
95/ 87
75/100
39/ 70
77/ 30
75/100
39 / 70
77/ 30
97/100
83/ 90
61/ 82
91/100
92/ 57
107/100
109/ 96
27/115
166/100
164/ 74
131/ 60
112/100
77/ 62
114/ 32
91/100
106/ 28
91/100
106/ 40
104/100
78/ 60
103/ 49
83/100
85/ 64
91/100
106/ 40
105/100
120/ 29
105/100
120/ 42
105/100
120/ 42
146/100
148/ 65
111/ 40
Estimated Retention
Time (min)
15.83
16.10
16.96
17.49
17.61
17.86
18.48
19.01
19.73
20.20
20.41
20.81
20.92
20.92
22.53
22.65
23.18
23.31
(continued)
-------
T014-64
TABLE 2. ION/ABUNDANCE AND EXPECTED RETENTION TIME FOR
SELECTED VOCs ANALYZED BY GC-MS-SIM (cont.)
Compound
Ion/Abundance
(amu/% base peak)
Expected Retention
Time (min)
Benzyl chloride («-Chlorotoluene)
p-Dichlorobenzene (1,4-Dichlorobenzene)
o-Dichlorobenzene (1,2-Dichlorobenzene)
1,2,4-Trichlorobenzene
Hexachlorobutadiene (1,1,2,3,4,4
Hexachloro-1,3-butadi ene)
91/100
126/ 26
146/100
148/ 65
111/ 40
146/100
148/ 65
111/ 40
180/100
182/ 98
184 / 30
225/100
227/ 66
223/ 60
23.32
23.41
23.88
26.71
27.68
-------
TO14-65
TABLE 3. GENERAL GC AND MS OPERATING CONDITIONS
Chromatography
Column
Carrier Gas
Injection Volume
Injection Mode
Temperature Program
Initial Column Temperature
Initial Hold Time
Program
Final Hold Time
Mass Spectrometer
Mass Range
Scan Time
El Condition
Mass Scan
Detector Mode
FID System (Optional)
Hydrogen Flow
Carrier Flow
Burner Air
Hewlett-Packard OV-1 crosslinked
methyl silicone (50 m x 0.31-mm I.D.,
17 urn film thickness), or equivalent
Helium (2.0 cm3/min at 250°C)
Constant (1-3 uL)
Splitless
-50°C
2 min
8°C/min to 150°C
15 min
18 to 250 amu
1 sec/scan
70 eV
Follow manufacturer's instruction for selecting
mass selective detector (MS) and selected ion
monitoring (SIM) mode
Multiple ion detection
30 cm3/minute
30 cm^/minute
400 cm^/minute
-------
T014-66
TABLE 4. 4-BROMOFLUOROBENZENE KEY IONS AND ION ABUNDANCE CRITERIA
Mass Ion Abundance Criteria
50 15 to 40% of mass 95
75 30 to 60% of mass 95
95 Base Peak, 100% Relative Abundance
96 5 to 9% of mass 95
173 <2% of mass 174
174 >50% of mass 95
175 5 to 9% of mass 174
176 >95% but< 101% of mass 174
177 5 to 9% of mass 176
-------
T014-67
TABLE 5. RESPONSE FACTORS (ppbv/area count) AND
EXPECTED RETENTION TIME FOR GC-MS-SIM
ANALYTICAL CONFIGURATION
Response Factor Expected Retention
Time (minutes)
lUliipuunua
Freon 12
Methyl chloride
Freon 114
Vinyl chloride
Methyl bromide
Ethyl chloride
Freon 11
Vinylidene chloride
Dichloromethane
Trichlorotrifluoroethane
1,1-Dichloroethane
cis-l,2-Dichloroethylene
Chloroform
1,2-Dichloroethane
Methyl chloroform
Benzene
Carbon tetrachloride
1,2-Dichloropropane
Trichloroethylene
ci s-1 ,3-Dichl oropropene
trans-l,3-Dichloropropene
1,1,2-Trichloroethane
Toluene
1,2-Dibromoethane (EDB)
Tetrachloroethylene
Chlorobenzene
Ethyl benzene
m,p-Xylene
Styrene
1 ,1 ,2 ,2-Tetrachl oroethane
o-Xylene
4-Ethyltoluene
1 , 3, 5-Tri methyl benzene
1 ,2 ,4-Tri methyl benzene
m-Dichlorobenzene
Benzyl chloride
p-Dichlorobenzene
o-Dichlorobenzene
1,2,4-Trichlorobenzene
Hexachlorobutadiene
0.6705
4.093
0.4928
2.343
2.647
2.954
0.5145
1.037
2.255
0.9031
1.273
1.363
0.7911
1.017
0.7078
1.236
0.5880
2.400
1.383
1.877
1.338
1.891
0.9406
0.8662
0.7357
0.8558
0.6243
0.7367
1.888
1.035
0.7498
0.6181
0.7088
0.7536
0.9643
1.420
0.8912
1.004
2.150
0.4117
5.01
5.64
6.55
6.71
7.83
8 A O
.43
9.87
10.93
11.21
11.60
i n c f\
12.50
13.40
1*5 "I C
13.75
14.39
14.62
15.04
15.18
15.83
1C 1 f\
16.10
1C f\C
16.96
UA rt
.49
Uf -m
.61
17.86
18.48
19.01
1 f\ TO
19.73
20.20
20.41
o r\ on
Zu.oO
20.92
20.92
22.53
22.65
f\f\ 10
23.18
23.31
23.32
23.41
oo o o
23.88
26.71
27.68
-------
T014-68
TABLE 6. GC-MS-SIM CALIBRATION TABLE
*** External Standard *•**
Operator: JDP
Sample In-fc :
Misc In-fo:
Integration Fi1
SYR 1
Name : DATA:SYR2A02A.I
Sequence Index: 1
8 Jan 87 10:02
Bottle Number : 2
Last Update: 8 Jan 87 8: 13 am
Re-ference Peak Window: 5.00 Absolute Minutes
Non-Re-ference Peak Windows O.40 Absolute Minutes
Sample Amount: O.OOO Uncalibrated Peak RF: 0.000 Multiplier: 1.667
Compound
Name
FREON 12
METHYLCHLORI
FREON 114
VINYLCHLORID
METHYLBROMID
ETHYLCHLORID
FREON 11
VINDENECHLOR
DICHLOROMETH
ALLYLCHLORID
3CHL3FLUETHA
1,1DICHLOETH
c-l,2DICHLET
CHLOROFORM
1,2DICHLETHA
METHCHLOROFO
BENZENE
CARBONTETRAC
1,2DICHLPROP
TRICHLETHENE
c-l,3DICHLPR
t-l,3DICHLPR
1,1,2CHLETHA
TOLUENE
EDB
TETRACHLETHE
CHLOROBENZEN
ETHYLBENZENE
m,p-XYLENE
STYRENE
TETRACHLETHA
o-XYLENE
4-ETHYLTOLUE
1,3,5METHBEN
1,2,4METHBEN
m-DICHLBENZE
BENZYLCHLORI
p-DICHLBENZE
o-DICHLBENZE
1,2,4CHLBENZ
HEXACHLBUTAD
Ret
Ti me
• 5.020
5.654
6.525
6 . 650
7.818
8.421
9. 940
10.369
11. 187
1 1 . 225
1 1 . 578
12.492
13.394
13.713
14.378
14.594
1-5. OO9
15. 154
15.821
16.067
16.941
17.475
17.594
17.844
18.463
1 8 . 989
19.705
20. 168
20.372
20.778
20.887
20.892
22.488
22.609
23. 144
23.273
23.279
23.378
23.850
26.673
~*~7 i"1*""*
4. 1 m Ow' /
Si gnal
Descripti on
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
85.
50.
85.
62.
94.
64.
101.
61.
49.
41.
151.
63.
61.
83.
62.
97.
78.
117.
63.
130.
75.
75.
97.
91.
107.
166.
112.
91.
91.
1 04 .
83.
91.
105.
1 05 .
105.
146.
91.
146.
146.
1 80 .
225.
00 amu
OO amu
OO amu
OO amu
OO amu
OO amu
00 amu
OO amu
OO amu
OO amu
00 amu
00 amu
OO amu
OO amu
OO .amu
OO amu
OO amu
OO amu
OO amu
OO amu
OO amu
OO amu
OO amu
OO amu
00 amu
OO amu
OO amu
OO amu
00 amu
00 amu
00 amu
00 amu
OO amu
OO amu
OO amu
OO amu
00 amu
OO amu
00 amu
OO amu
00 amu
Area
12893
4445
7067
2892
2401
2134
25069
5034
4803
761
5477
5O52
4761
.5327
5OO9
6656
8352
5888
3283
4386
2228
1626
2721
14417
4070
6874
5648
11084
17989
3145
4531
9798
7694
6781
7892
3046
3880
6090
2896
562
63O9
Amount
4011 pptv
2586 pptv
1215 pptv
1929 pptv
1729 pptv
2769 pptv
6460 pptv
1700 pptv
2348 pptv
8247 pptv
1672 pptv
1733 pptv
1970 pptv
1673 pptv
2263 pptv
2334 pptv
2167 pptv
1915 pptv
179r pptv
2109 pptv
987.3 pptv
689.2 pptv
1772 pptv
2733 pptv
1365 pptv
2065 pptv
1524 pptv
1842 pptv
3790 pptv
1695 pptv
1376 pptv
2010 pptv
1481 pptv
1705 pptv
2095 pptv
1119 pptv
1006 pptv
2164 pptv
1249 pptv
767. 1 pptv
1789 pptv
.j.
*
*
*
*
*•
-------
T014-69
TABLE 7. TYPICAL RETENTION TIME (MIN) AND
CALIBRATION RESPONSE FACTORS (ppbv/area count)
FOR TARGETED VOCs ASSOCIATED WITH FID
AND ECD ANALYTICAL SYSTEM
Peak
Number1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28 x
29
30
31
32
33
34
35
36
37
38
39
40
Compound
rreon 12
Methyl chloride
Freon 114
Vinyl chloride
Methyl bromide
Ethyl chloride
Freon 11
Vinylidene chloride
Dichloromethane
Trichlorotrifluoroethane
1,1-Dichloroethane
ci s-l,2-Dichloroethylene
Chloroform
1,2-Dichl oroethane
Methyl chloroform
Benzene
Carbon tetrachloride
1,2-Dichl oropropane
Trichloroethylene
ci s-l,3-Dichloropropene
trans-l,3-Dichloropropene
1 ,1 ,2-Trichl oroethane
Toluene
1,2-Dibromoethane (EDB)
Tetrachl oroethylene
Chlorobenzene
Ethyl benzene
m,p-Xylene
Styrene
1 ,1 ,2 ,2-Tetrachl oroethane
o-Xylene
4-Ethyltoluene
1, 3, 5-Tri methyl benzene
1 ,2, 4-Tri methyl benzene
m-Dichlorobenzene
Benzyl chloride
p-Dichlorobenzene
o-Dichlorobenzene
1 ,2 ,4-Trichl orobenzene
Hexachlorobutadiene
detention
Time (RT) ,
minutes
3.65
4.30
5.13
5.28
6.44
7.06
8.60
9.51
9.84
10.22
11.10
11.99
12.30
12.92
13.12
13.51
13.64
14.26
14.50
15.31
15.83
15.93
16.17
16.78
17.31
18.03
18.51
18.72
19.12
19.20
19.23
20.82
20.94
21.46
21.50
21.56
21.67
22.12
24.88
25.82
FID T
Response 1
Factor (RF)
(ppbv/area
count)
3.465
0.693
0.578
0.406
0.413
6.367
0.347
Of\ f\ ^
.903
0.374
0.359
0.368
1.059
0.409
0.325
0.117
1.451
0.214
0.327
0.336
0.092
0.366
0.324
0.120
0.092
0.095
0*1 fl O
.143
01 rt f\
.100
0.109
0.111
0.188
0.188
0.667
0.305
ECD
Response
-actor
(ppbv/area
count x 10~b)
13.89
22.32
f\f *) A
26.34
1.367
3.955
U*l A
.14
3.258
1.077
8.910
5.137
1.449
9.856
1.055
1 Refer to Figures 15 and 16 for peak location
-------
T014-70
TABLE 8. TYPICAL RETENTION TIME (minutes) FOR
SELECTED OR6ANICS USING GC-FID-ECD-PID*
ANALYTICAL SYSTEM
Compound
Acetylene
1,3-Butadiene
Vinyl chloride
Chloromethane
Chi oroethane
Bromoethane
Methylene Chloride
trans-l,2-Dichloroethylene
1,1-Dichl oroethane
Chloroprene
Perfluorobenzene
Bromo chloromethane
Chloroform
1,1,1-Trichl oroethane
Carbon Tetrachloride
Benzene/1 ,2-Dichl oroethane
Perfluorotoluene
Trichloroethylene
1,2-Dichloropropene
Bromodichloromethane
trans -1,3-Dichloropropylene
Toluene
ci s-1 ,3-Dichl oropropylene
1,1,2-Trichloroethane
Tetrachloroethylene
Dibromo chloromethane
Chlorobenzene
m/p-Xylene
Styrene/o-Xylene
Bromofluorobenzene
1,1,2,2-Tetrachloroethane
m-Dichlorobenzene
p-Dichlorobenzene
o-Dichlorobenzene
Retention Time minutes)
FID
2.984
3.599
3.790
5.137
5.738
8.154
9.232
10.077
11.190
11.502
13.077
13.397
13.768
14.151
14.642
15.128
15.420
17.022
17.491
18.369
19.694
20.658
21.461
21.823
22.340
22.955
24.866
25.763
27.036
28.665
29.225
32.347
32.671
33.885
ECD
__
__
•» M
W «
__
13.078
13.396
13.767
14.153
14.667
15.425
17.024
17.805
19.693
•» *»
21.357
22.346
22.959
28.663
29.227
32.345
32.669
33.883
PIP
3 594
*J • -J J"
3 781
+r • / "— *JL
9 218
•J • t_ Xw
10.065
11 491
•*• J- • i -• J.
13.069
13.403
13.771
14 158
±~ + ± *j \j
14.686
15 114
* *J • J. X *
15 41?
J. *J • T^ X t.
17 014
* r • w X ~
17 522
JL / « v/ L. 4.
19.688
20.653
21.357
22.335
22.952
?4 ftfil
t.1* .001
25 757
(~ -J + 1 %/ /
27.030
28.660
29.228
32.342
32.666
33.880
Varian® 3700 GC equipped with J & W Megabore® DB 624 Capillary
Column (30 m X 0.53 I.D. mm) using helium carrier gas.
-------
T014-71
TABLE 9. GC-MS-SIM CALIBRATION TABLE
Last Updates IB Dec 86 7:54 am
Re-ference Peak Window: 5.OO Absolute Minutes
Non-Re-ference Peak Window: 0.40 Absolute Minutes
Sample Amount: O.OOO Uncalibrated Peak RF: O.OOO Multiplier: l.OOO
Ret Time Pk#
5.008
5.690
6.552
6.709
7.831
8.431
9 . 970
10.927
1 1 . 209
11.331
11.595
12.502
13.403
13.747
1 4 . 337
14.623
-J5.038
•15.133
15.829
16.096
16.956
17.492
17.610
17.362
13.485
19.012
19.729
2O. 195
20.407
2O. 306
20.916
2O. 921
22.523
22.648
23. 179
23.3O7
23.317
23.413
23.335
26.714
27.680
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
IS
19
20
21
22
23
24
25
26
27
23
29
3O
31
32
33
34
35
36
37
33
39
40
41
Signal Descr Amt pptv
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
85 . 00 amu
SO. 00 amu
35.00 amu
62.00 amu
94.00 amu
64.00 amu
101. OO amu
61.0O amu
49.0O amu
4 1 . OO amu
151. OO amu
63. OO amu
6 1 . 00 amu
83. OO amu
62 . OO amu
97 . 00 amu
73.00 amu
117.00 amu
63 . 00 amu
130.00 amu
75.OO amu
75 . OO amu
97 . 00 amu
9 1 . 00 amu
107.00 amu
1 66 . OO amu
112. OO amu
9 1 . OO amu
9 1 . 00 amu
1 O4 . 00 amu
33 . OO amu
9 1 . OO amu
105.0O amu
1O5.OO amu
1 05 . OO amu
146.OO amu
9 1 . 00 amu
146.OO amu
146.OO amu
1 BO . OO amu
225 . OO amu
13620
12720
8380
3050
12210
12574
1238O
7890
1276O
12650
7420
12710
12630
7670
904O
810O
1076O
3340
1273O
8750
454O
338O
12690
10O1O
6710
783O
716O
1274O
254OO
1239O
1169O
1 1 085
1256O
1262O
1271O
1265O
7900
1239O
1351O
1552O
747O
Lvl CArea]
1 72974
1 36447
1 81251
1 20118
1 28265
1 16149
1 8O088
1 38954
1 43507
1 1945
1 40530
1 61595
1 509OO
1 4O585
1 33356
1 33503
1 69119
1 42737
1 33375
1 30331
1 . 17078.
1 13294
1 32480
1 8BO36
1 3335O
1 43454
1 44224
1 127767
1 200973
1 38332
1 64162
1 9OO96
1 108747
1 83666
1 79333
1 574O9
1 50774
1 58127
1 52233
1 18967
1 43920
Pk-Type .Partial Name
1 FRECIM 12
1 ItETHYLCHLQRID
1 FREDN 114
1 VINYLCHLORIDE
1 METHYLBROMIDE
1 ETHYLCHLORIDE
1 FREON 11
1 VINDENECHLORi
1 DICHLOROMETHA
1 ALLYLCHLORIDE
1 3CHL3FLUETHAN
1 1,1DICHLCETHH
1 c-l,2DICHLETH
1 CHLOROFORM
1 1.2DICHLETHAN
1 METHCHLORCFOR
1 BENZENE
1 CARBCNTETRACH
1 1.2DTCHLFRCPA
1 TRICHLETHENE
1 c-i,3DICHl.PRO
1 t-l,3DICHLPRC
1 1 , 1,2CHLE7HAN
1 TOLUENE
1 EDB
1 TETRACKLETMEN
1 CHLQRGBENZENE
1 ETHYLBENZE^4E
1 m,p~XYLENE
1 STYRENE
1 TETRACHLETHAN.
1 o-XYLENE
1 4-ETHYLTOLUEN
1 1,3,SMETHBENZ
1 1,2,4METHBENZ
1 m-DICHLBEN2EN
1 BENZYLCHLCRID
1 p-DICHLBEHZEN
1 o-DICHLBENZEN
1 1,2,4CHLBENZE
1 HEXACHLBUTADI
-------
T014-72
TABLE 10. EXAMPLE OF HARD-COPY OF GC-MS-SIM ANALYSIS
Data -file: DATA: SYR2A02A. D
File type: GC / MS DATA FILE
Name In-fo: SYR 1
Mi sc In-fo:
Operator : JDP
Date : 8 Jan 37
Instrment: MS_5970
Inlet : GC
Sequence index; : 1
Als bottle num : 2
Replicate num : 1
10:02 am
TIC af DRTR.-EVR3RD2R.D
IBQCl
1EBB
14BB
1BBB
BOB
BBB'
2BB-
tj.
IB
15
2Q
25
3Q
*** integration Parameters ***
FALSE : Shoulder Detection Enabled
0.020 : Expected Peak Width
-------
T014-73
TABLE 10. EXAMPLE OF HARD-COPY OF GC-MS-SIM ANALYSIS (cont.)
Operator: JDP
Sample In-fc : SYR 1
Misc In-fo:
Integration File Name i DATA:SYR2A02A. I
Sequence Index: 1
8 Jan 87 10:02 *»•
Bottle Number t 2
Last Update: 8 Jan 87 6: 13 am
Re-ference Peak Window: 5.00 Absolute Minutes
Non-Re-ference Peak Window: 0.40 Absolute Minutes
Sample Amount: 0.000 Uncalibrated Peak RF: 0.000 Multiplier: 1.667
Compound
Name
amu FREON 12
amu METHYLCHLOR1
amu FREON 114
amu VINYLCHLORID
amu METHYLBROMID
amu ETHYLCHLORID
amu FREON 11
amu VINDENECHLOR
amu DICHLOROMETH
amu ALLYLCHLORID
amu 3CHL3FLUETHA
amu 1,1DICHLOETH
amu c-l,2DICHLET
amu CHLOROFORM
.amu 1,2DICHLETHA
amu METHCHLOROFD
amu BENZENE
amu CARBONTETRAC
amu 1,2DICHLPROP
amu TRICHLETHENE
amu c-l,3DICHLPR
amu t-l,3DICHLPR
amu 1,1,2CHLETHA
amu TOLUENE
amu EDB
amu TETRACHLETHE
-amu CHLOROBENZEN
amu ETHYLBENZENE
amu m,p-XYLENE
amu STYRENE
amu TETRACHLETHA
amu o-XYLENE
amu 4-ETHYLTOLUE
amu 1,3,5METHBEN
amu 1,2,4METHBEN
amu m-DICHLBENZE
amu BENZYLCHLORI
amu p-DICHLBENZE
amu o-DICHLBENZE
amu 1,2,4CHLBENZ
amu HEXACHLBUTAD
Peal:.
Num Type
1
2
A
C"(
6
"T
/
8
«?
«*!
i
• »*i
j, *^
1 T,
1-
15
\ e
•7
13
1s?
20
21
/•%*".
^•'~.
2*
*•>«•
«» *•'
26
27
25
'?
30
31
*Tt~,
W «
33
34
3S
5
37
3S
39
40
41
Int
Type
1 PP '
1 PP
] BP
1 PB
1 BP
1 BB
1 BV
1 BP
1 BP
1 PP
1 BP
1 BP
3 VP
1 PH
1 BP
1 PB
1 VP
1. VP
1 BB
1 BB
1 PB
1 BP
1 BB
1 BV
1 PB
1 PH
1 PB
1 BP
1 PB
1 BV
1 BH
1 BP
1 W
1 VB
1 BB
1 BV
1 VV
1 VB
1 BP
1 BB
1 BB
Ret
Time
5.020
5.654
6.525
6 . 650
7. BIB
8.421
9.940
10.369
11.187
1 1 . 225
1 1 . 578
12.492
13.394
13.713
14.378
14.594
V5.O09
15. 154
15.821
16.067
16.941
17.475
17.594
17.844
18.463
18.989
19.705
20. 16B
20.372
20.778
20.887
20.892
22.488
22.609
23. 144
23.273
23.279
23.378
23. 850
26.673
27.637
Si
gnal
Descripti on
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
Mass
B5.OO £
50.00 c
85.00 i
62. OO i
94.00 c
64.00 i
101.00 •
61.00 i
49.00 i
41.00 i
151.00 i
63.00 •
61.OO •
•83.00 .
62.00 .,
97.00 .
78.00 .
117.OO
63.00
130.00
75.00
75.00
97 . 00
91.00
1 07 . OO
1 66 . OO
112.OO-
9 1 . OO
91.OO
1 04 . OO
83 . 00
91.00
105.00
105.00
105.00
146.00
91.00
146.00
146.00
180.00
Mass 225.00
Area
12893
4445
7067
2892
2401
2134
25069
5034
4803
761
5477
5052
4761
.5327
5009
6656
8352
58BB
32B3
4386
222B
1626
2721
14417
4070
6B74
5648
11084
17989
3145
4531
9798
7694
67S1
7892
3046
3880
609O
2896
562
6309
Amount
4011 pptv
2586 pptv
1215 pptv
1929 pptv *
1729 pptv
2769 pptv +
6460 ppt\
1700 pptv
2343 pptv
8247 pptv *
1672 pptv
1738 pptv *
1970 pptv
1673 pptv
2263 pptv
2334 pptv
2167 pptv
1915 pptv
1799 pptv *
2109 pptv
987.3 pptv
689.2 pptv
1772 pptv
2733 pptv
1365 pptv *•
2065 pptv
1524 pptv
1842 pptv
3790 pptv
1695 pptv
1376 pptv
2010 pptv
1481 pptv
1705 pptv
2095 pptv
1119 pptv
1006 pptv
2164 pptv
1249 pptv
767. 1 pptv
1789 pptv
-------
GC-MS-SCAN
(Section 10.4.2)
T014-74
Receive
Sample
Canister
(Section
9.2.2)
Log Sample In
(Section 10.4.1.2)
Check and Record
initial Pressure
(Section 10.4.1.3)
Analyze
<83kPa
(12psig).
(Optional)
GC-MS-SIM
(Section 10.4.3)
Pressurize
with N2 To
138 kPa
(20pslg)
Record Final
Pressure
(Section 10.4.1.3)
Calculate
Dilution Factor
(Section 10.4.1.4)
GC-Multldetector
(GC-FID-ECD-PID)
(Section 10.4.4)
Non-Specific Detector (FID)
(Optional)
FIGURE 1. ANALYTICAL SYSTEMS AVAILABLE FOR CANISTER
VOC IDENTIFICATION AND QUANTITATION
-------
Inlet
~1.6 Meters
(-5 ft)
1
Ground
Level
Vent
T014-75
To AC
Insulated Enclosure
Inlet
Manifold
M M
Vacuum/Pressure
Gauae
Electronic
Time |