&EPA
United States Environmental Monitoring Systems
Environmental Protection Laboratory
Agency Research Triangle Park NC 2771 1
EPA/600/4-87-006
September 1986
Research and Development
Supplement to
EPA/600/4-84/041
Compendium of
Methods for the
Determination of
Toxic Organic
Compounds in
Ambient Air
-------
-------
NOTICE
SUPPLEMENT TO COMPENDIUM OF METHODS FOR THE
. DETERMINATION OF TOXIC ORGANIC COMPOUNDS IN AMBIENT AIR
To holders of Compendium of Methods for the Determination of Toxic Organic
Compounds in Ambient Air (EPA-600/4-84-041). dated April 1984:
The accompanying document is a supplement to the Compendium referenced
above and contains the pages necessary to update the Compendium as of
September 1986. The supplement is only an update and is intended to be used
in conjunction with the original Compendium published by the U.S. Environmental
Protection Agency, Environmental Monitoring Systems Laboratory, Quality
Assurance Division, in April 1984 (EPA-600/4-84-041). Copies of this document
may be obtained, as supplies permit, from:
U. S. Environmental Protection Agency
Center for Environmental Research Information
Compendium Registration
26 W. St. Clair Street
Cincinnati, Ohio 45268
Attention: Distribution Record System
Copies of the Compendium dated September 1986 will contain the supplement.
Included in this supplement are all revisions pertinent to the update,
along with instructions for merging the supplementary pages with the original
document. Four new methods are added to the Compendium, and a new title page,
Table of Contents, and new Tables 1 and 2 are included to reflect the added
methods.
-------
Any questions, comments, or suggestions regarding this supplement or the
Compendium should be directed to the U. S. Environmental Protection Agency,
Environmental Monitoring Systems Laboratory, Quality Assurance Division,
MD-77, Research Triangle Park, NC, 27711; (919) 541-2665, (FTS: 629-2665).
Instructions for Merging the Supplement with the Compendium:
Delete Insert
Original Title Page (4/84) New Title Page (9/86)
Original Disclaimer, page ii (4/84) New Disclaimer, page ii (9/86)
Original CONTENTS, page iii (4/84) New CONTENTS, page iii (9/86)
Pages iv through viii (4/84) Pages iv through viii (9/86)
Method T06 (9/86)
Method T07 (9/86)
Method T08 (9/86)
Method T09 (9/86)
-------
EPA/600/4-87/006
September 1986
COMPENDIUM OF METHODS FOR THE DETERMINATION
OF TOXIC ORGANIC COMPOUNDS IN AMBIENT AIR
by
R.M. Riggin
Battelle-Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
and
William T. Winberry, Jr.
Norma V. Tilley
Engi neeri ng-Science
One Harrison Park, Suite 200
401 Harrison Oaks Boulevard
Cary, North Carolina 27511
Contract No. 68-02-3888
Task No. 44
EPA Project Officer:
L.J. Purdue
Quality Assurance Division
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
-------
Disclaimer
This report has been reviewed by Environmental Monitoring Systems
Laboratory, U. S. Environmental Protection Agency, and approved for publi-
cation. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
The information in this document has been funded wholly or in part by
the U. S. Environmental Protection Agency under contract number 68-02-3888.
It has been subjected to the Agency's peer and administrative review, and it
has been approved for publication as an EPA document.
-------
CONTENTS
FOREWORD iv
INTRODUCTION v
METHODS
Tenax GC Adsorption Method TO-1
Carbon Molecular Sieve Adsorption Method TO-2
Cryogenic Trapping Method TO-3
High Volume Polyurethane Foam Sampling Method TO-4
Dinitrophenylhydrazine Liquid Impinger Method TO-5
Sampling
Liquid Impinger with High Performance Method TO-6
Chromatography (HPLC)
Thermosorb/N Adsorption with Gas Method TO-7
Chromatography/Mass Spectrometry (GC/MS)
Sodium Hydroxide Liquid Impinger with Method TO-8
High Performance Liquid Chromatography (HPLC)
High Volume Polyurethane Foam Sampling (PUF) Method TO-9
with High Resolution Gas Chromatography/High
Resolution Mass Spectrometry (HRGC/HRMS)
APPENDIX A - EPA Method 608
iii
-------
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 regulations, and to evaluate the
effectiveness of health and environmental protection 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, an addition of four specific methods has been made. With this
addition, the Compendium now contains nine standardized sampling and
analysis procedures. As advancements are made, the current methods
may be modified from time to time along with new additions to the
Compendium.
John C. Puzak
Deputy Director
Environmental Monitoring Systems Laboratory
Research Triangle Park, North Carolina
-------
INTRODUCTION
This Compendium has been prepared to provide regional,
state, and local environmental regulatory agencies, as well as other
interested parties, with specific guidance on the determination of
selected toxic organic compounds in ambient air. Recently, a
Technical Assistance Document (TAD) was published which provided
guidance to such persons (1). Based on the comments received con-
cerning the TAD the decision was made to begin preparation of a
Compendium which would provide specific sampling and analysis
procedures, in a standardized format, for selected toxic organic com-
pounds.
The current Compendium consists of nine procedures which
are considered to be of primary importance in current toxic organic
monitoring efforts. Additional methods will be placed in the Compendium
from time to time, as such methods become available. The original
methods were selected to cover as many compounds as possible (i.e.,
multiple analyte methods were selected). The additional methods are
targeted toward specific compounds, or small groups of compounds which,
for various technical reasons, cannot be determined by the more general
methods.
Each of the methods writeups is self contained (including pertinent
literature citations) and can be used independent of the remaining portions
of the Compendium. To the extent possible the American Society
for Testing and Materials (ASTM) standardized format has been used, since
most potential users are familiar with that format. Each method has been
identified with a revision, number and date, since modifications to the
methods may be required in the future.
Nearly all the methods writeups have some flexibility in the procedure.
Consequently, it is the user's responsibility to prepare certain standard
operating procedures (SOPs) to be employed in that particular laboratory.
Each method indicates those operations for which SOPs are required.
Table 1 summarizes the methods currently in the Compendium. As shown
in Table 1 the first three methods are directed toward volatile nonpolar
compounds. The user should review the procedures as well as the back-
ground material provided in the TAD (1) before deciding which of these
methods best meets the requirements of the specific task.
Table 2 presents a partial listing of toxic organic compounds which
can be determined using the current set of methods in the Compendium.
Additional compounds may be determined by these methods, but the user
must carefully evaluate the applicability of the method before use.
Reference
1. 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.
-------
TABLE 1. LIST OF METHODS IN THE COMPENDIUM
Method
Number
TO-1
TO-2
TO-3
TO-4
TO-5
TO-6
TO-7
TO-8
TO-9
Description
Types of
Compounds Determined
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 organic
(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-Ni trosodimethyl ami ne
Cresol/Phenol
Dioxin
VI
-------
TABLE 2. LIST OF COMPOUNDS OF PRIMARY INTEREST
Compound
Acetaldehyde
Acrolein
Acrylonitrlle
Ally! Chloride
Benzaldehyde
Benzene
Benzyl Chloride
Applicable
Method(s)
Comments
TO-5
TO-5
TO-2, TO-3
TO-2, TO-3
TO-5
TO-1, TO-2, TO-3
TO-1, TO-3
TO-3 yields better recovery
data than TO-2.
TO-3 yields better recovery
data than TO-2.
TO-3 yields better recovery data.
Carbon Tetrachloride (TO-1?), TO-2, TO-3
Chlorobenzene
Chloroform
Chloroprene
(2-Chloro-l,3-buta-
diene)
Cresol
4,4'-DDE
4,4'-DDT
1,4-Dichlorobenzene
Dioxin
Ethylene dichloride
(1,2-Dichloroethane)
Formaldehyde
Methyl Chloroform
(1,1,1-Trichloroethane)
TO-1, TO-3
(TO-1?), TO-2, TO-3
TO-1, TO-3
TO-8
TO-4
TO-4
TO-1, TO-3
TO-9
(TO-1?), TO-2, TO-3
TO-5
(TO-1?), TO-2, TO-3
Breakthrough volume is very low
using TO-1.
Breakthrough volume is very Tow
using TO-1
The applicability of these methods
for chloroprene has not been
documented.
Breakthrough volume very low
using TO-1.
Breakthrough volume very low
using TO-1.
Methylene chloride TO-2, TO-3
Nitrobenzene TO-1, TO-3
N-Nitrosodimethyl amine TO-7
vn
-------
Compound
TABLE 2, (Continued)
Applicable
Method(s)
Comments
Perchloroethylene
(Tetrachloroethylene)
Phenol
Phosgene
Polychlorinated bi-
phenyls (PCBs)
Propanal
Toluene
Tri chloroethy 1 ene
Vinyl Chloride
Vinylidine Chloride
(1,1-di chloroethene)
o,m,p-Xylene
TO-1, (TO-2?), TO-3 TO-2 performance has not been
documented for this compound.
TO-8
TO-6
TO-4
TO-5
TO-1, TO-2, TO-3
TO-1, TO-2, TO-3
TO-2, TO-3
TO-2, TO-3
TO-1, TO-3
vm
-------
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
jH5-20% 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^), 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^).
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 jiitrogen 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
(, ,T.Uy 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 oz. 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 impinger 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
N
N '
where
QA = average flow rate (mL/minute).
Qls 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:
- . (T24)QA
1,000
tul £
where '
Vm = total sample volume (L) at measured
temperature and pressure.
T2 = stop time.
Tj = start time. • . -
T-]-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
rat i o.
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
.1.0. Teflon tubing should be placed after the detector to
eliminate further mobile phase outgassing.
-------
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.
Vj = 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).
T/\ = 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 _£
V
E
VI
where
W,j = total quantity of carbanilide (ug) in the sample.
RFC = response factor calculated in Section 12.7.
R
-------
T06-13
CA (ppbv) = CA (ng/L) x 24.4
99
where
CA (ng/L) is calculated using Vs.
14. 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.
14.1 Standard Operating Procedures (SOPs).
14.1.1 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 reagent and
sample:;; 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.
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 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
T06-16
REFERENCES
1. Spicer, C. W., R. M. Riggin, M. W. Holdren, F. L. DeRoos, and
R. N. Lee. Atmospheric Reaction Products from Hazardous Air
Pollutants, Final Report on Contract 68-02-3169 (WA-33/40),
U.S. Environmental Protection Agency, Research Triangle Park,
N.C., July. 1984.
2. Method 219, "Phosgene in Air," Manual of Analytical Methods,
National Institute for Occupational Safety and Health.
3. Annual Book of ASTM Standards, Part 11.03, "Atmospheric Analysis,"
American Society for Testing and Materials, Philadelphia,
Pennsylvania, 1983.
4. 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.
5. "Method 6 Determination of S02 Emissions from Stationary Sources,"
Federal Register, Vol. 42., No. 160, August, 1977.
-------
T06-17
< uj
< V)
Q >
V)
eo
• m
uj I" CC
S t
>< Q
UJ
CO
CO
o
o
Q.
HI
QC
-------
UJ
o
<
u
Z]
55
c.i
f
T06-18
PS,
1 >-
CO
UJ CC
CL C9
5 z
K\) •<-» 3
i r
)i>WV*-
»::
S *
O) o>
>^s
•*- £
o *~
- "o
E c
o c
^~~ ^
Ul uj
E
o
o
cc
O
UJ <
Q.
UI
<
O
cc
Millilllll
I-
M"
-LU
EO
CM
LLJ
cc
-------
PROJECT:
SITE:
LOCATION:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
T06-19
-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,*Q
mL/mi n
Ambient
Temperature
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
_ Qj +Q2 +Q3 — QN
N
x 1
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. TYPICAL SAMPLING DATA FORM
-------
T06-20
9)
in
•
ro
f
o
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
2.75300 2.74
10020.20000 3.59
TOTAL 10023.00000
AREA
2753 L
10020345 L
RF
O.OOOOOOEO
O.OOOOOOEO
FIGURE 4. CHROMATOGRAM FOR 3 ppbv OF
PHOSGENE SPIKED INTO CLEAN AIR
-------
T06-21
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
V
TIME-
CONG
AREA
COUNTS
2126577
4243289
6312128
8373790
10020345
3.60
(d)
3.59
(e)
UJ
—3
TIME-
4/tg
o TIME-
z 5/ig
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 = -jr=r
Example Calculation:
Peak Height = DE = 100 mm
10% Peak Height = BD = 10 mm
Peak Width at 10% Peak Height = AC = 23 mm
AB = 11 mm
BC = 12 mm
Therefore: Asymmetry Factor = — = 1.1
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
200
Recovery,
%
63
87
99
109
99
96
Standard
Deviation
13
14
3
12
14
7
-------
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-
nitrosodimethylamine (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/m^
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 determination. 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 D1356(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.
-------
T07-4
8.2 Dichloromethane - Pesticide quality, or equivalent.
8.3 Helium - Ultrapure compressed gas (99.9999%).
8.4 Perfl uorotributyl amine (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. Sampli ng
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
-------
9.9
Ql
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.
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
N
where
QA
e ..... QN
N =
average flow rate (mL/minute).
flow rates determined at beginning,
end, and immediate points during
sampling.
number of points averaged.
9.10 The total flow is then calculated using the following
equation:
.. x QA
1000
where
Vm = total sample volume (L) at measured
temperature and pressure.
T2 = stop time.
TI = start time.
T2-T] = 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:
v PA v 298
w _ w X A 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 6C/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:
where
c -
C-
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
e
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., j>4, 1947-1951 (1982).
(2) Fine, D. H., et. al, "N-Nitrosodimethylamine in Air," Bull. Env.
Cont. Toxicol.,^5, 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 -*•
r\
Coupling to
connect
Thermosorb® N
Adsorbent Cartridges
(a) MASS FLOW CONTROL
ROTAMETER
VENT
DRY
TEST
METER
••
_
•
—
•••
PUMP
\
T
rV
V
EEDL
/ALVI
^
E
(DRY TEST METER SHOULD NOT BE USED
FOR FLOW OF LESS THAN 500 ml/minutes)
coupling to
connect
Thermosorb® N
adsorbent
cartridge
(b) NEEDLE VALVE/DRY TEST METER
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:
Time
1.
2.
3.
4.
N.
Dry Gas
Meter
Reading
Rotameter
Reading
Flow
Rate,*Q
mL/mi n
Ambient
Temperature
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
Q
N
1000 * (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
-------
T07-19
UJ
Q:
cr
o
z
o
I
I
I
345
TIME (MIN.)
FIGURE 3. TOTAL ION CURRENT CHROMATOGRAM RESULTING
FROM INJECTION OF 15 jtL SAMPLE OF NDMA STANDARD (10
NG//iL IN ETHANOL).
-------
T07-20
o
VD
"> O
CM
o>
(D
.8
o
8
s
§
o o
CM
O
o
o<
if) o
*~ CO
O 00
— H
Z if)
d6
CO £.
Q. HI
o H
° tt
|<
0<
cog
CO Z
Ul
cc
D
o
-------
T07-21
Asymmetry Factor =
BC
AB
Example Calculation:
Peak Height = DE = 100 mm
10% Peak Height = BO = 10 mm
Peak Width at 10% Peak Height = AC = 23 mm
AB = 11 mm
BC = 12 mm
12
Therefore: Asymmetry Factor = —
1.1
FIGURE 5. PEAK ASYMMETRY CALCULATION
-------
T07-22
TABLE 1: 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 j+ 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
-------
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 methyl phenols (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 CDS 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 Tef1on®-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 Acetonitrile - 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:
QA =
where
QA = average flow rate (mL/minute).
Ql, Q2,....QN = fl°w 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:
_ x "A
m
1000
-------
T08-7
where
Vm = total volume (L) sampled at measured
temperature and pressure.
1"2 '= stop time.
TI = start time.
T2-Tj_ = 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:
y PA y 298
w _ u X A X
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.
PA = 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: €-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 27.4 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 component in the daily calibration standard
is used to calculate a response factor according to the following
equation:
RFC =
cc*Vl
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 cali-
bration standard.
Vj = volume (uL) of calibration standard injected.
Rc = 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:
Wrt = RFr X Rd X i X _
where
v
_
VA
Wd = total quantity of analyte (ug) in the sample.
RFC = response factor calculated in Section 11.6.
RCJ = response (area counts or other response units)
for analyte in sample extract.
VE = final volume (ml) of sample extract.
Vj = volume of extract (ulr) injected onto the HPLC
system.
VD = redilution volume (if sample was redi luted).
VA = aliquot used for redilution (if sample was
redi luted).
-------
T08-12
12.2 The concentration of analyte in the original sample is
calculated from the following equation:
Cfl = d x 1000
Vm (or VS)
where
CA = concentration of analyte (ng/L) in the original sample.
Wd = total quantity of analyte (ug) in sample.
Vm = total sample volume (L) under ambient conditions.
V$ = 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 (n9/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.
13.1 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
_
wl/2
i
where
N = column efficiency (theoretical plates).
tr - retention time (seconds) of analyte.
Wj_/2 = width 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., 53, 160-163 (1981).
(3) Shoup, R. E., and Mayer, 6. S., "Determination of Environmental
Phenols by Liquid Chromatography Electrochemistry," Anal. Chem.,
J54, 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 S0£ Emissions from Stationary Sources,"
Federal Register, Vol. 42., No. 160, August, 1977.
-------
T08-16
01
00
CO
_J
Q.
o
Q.
h-
UJ
Q:
-------
T08-17
O
CO
0.
CC
UJ
UJ
1
O
CC
CD
Z
CC
O
O
SBC
tt<
OH-
"-Z
5^
in QQ
S|
C0Z
Oco
130
Q.CO
oe UJ
iim+mii
UJ
o_ yj
>l
HO-
UJ
cc
-------
PROJECT:
SITE:
LOCATION:
INSTRUMENT MODEL NO:
PUMP SERIAL NO:
SAMPLING DATA
T08-18
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/mi n
Ambi ent
Temperature
°C
Barometric
Pressure,
mm Hg
Relative
Humidity, %
Comments
Total Volume Data**
Vm = (Final - Initial) Dry Gas Meter Reading, or
_Q1+ Q2+Q3 — QN
1
N 1000 * (Sampling Time in Minutes)
* Flow rate from rotameter or soap bubble calibrator
(specify which).
** Use data from dry gas meter if available.
L
L
FIGURE 3. EXAMPLE SAMPLING DATA SHEET
-------
T08-19
O
ro
OPERATING PARAMETERS
HPLG
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 #0
COLUMN SOLVENT OPR ID:
EXTERNAL STANDARD QUANTITATION
AMOUNT
790.82600
2686.95000
1645.46000
5123.24000
RT
8.81
11.30
12.22
EXP RT
AREA
790826 L
2686966 F
1645466 L
RF
O.QOOOOOEO
O.OOOOOOEO
O.OOOOOOEO
TIME
FIGURE 4. TYPICAL CHROMATOGRAM ILLUSTRATING
SEPARATION OF PHENOLS/CRESOLS BY HPLC
-------
T08-20
(c)
3.39
(a)
3.39
3.44
3.43
r--
oj
04
TIME
TIME
3fig
(e)
3.39
CONC.
AREA
COUNTS
4/*g
5|*g
249054
554609
804918
1038422
1296781
-rf
TIME
TIME
UJ
-3
FIGURE 5a-5e. HPLC CHROMATOGRAM OF VARYING
PHENOL CONCENTRATIONS
-------
T08-21
o
o
in
=)
o
o
o
o
LU
QC
o
o
in
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
Q,
CORRELATION COEFFICIENT:
0.999
I 2 3 4 £
PHENOL (fig)
FIGURE 6. CALIBRATION CURVE FOR PHENOL
-------
T08-22
Asymmetry Factor =
BC
Exampto Calculation:
Peak Height = DE = 100 mm
10% P«ak Height - BD * 10 mm
Peak Width at 10% Peak Height -
AB = 11 mm
BC = 12 mm
AC = 23 mm
Therefore: Asymmetry Factor
1?
11
= 1.1
FIGURE 7. PEAK ASYMMETRY CALCULATION
-------
Revision 1.0
September. 1986
METHOD T09
METHOD FOR THE DETERMINATION OF POLYCHLORINATED DIBENZO-
p-DIOXINS (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:
0 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD)
0 1,2.3,4,7,8-hexachlorodibenzo-p-dioxin (1,2,3,4,7,8-HXCDD)
0 Octachlorodibenzo-p-dioxin (OCDD)
0 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 15 pg/m^.
-------
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.
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 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 2,3,7,8-Tetrachlorodibenzo-
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 Einvironmental Protection Agency, Division of Air
Pollution Control, .April , 1986, IEPA/APC/86-011.
3. Summary of Method
3.1 Filters and adsorbent cartridges (containing PDF) 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 transformers 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.
-------
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
-------
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.
-------
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 HR6C/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.
-------
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 pi pets, 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 j^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.
-------
T09-10
[NOTE: Reuse of glassware should be minimized to avoid the risk of
cross-contamination. All glassware that is used, especially glassware
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 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.
-------
T09-ll(
8.8 Graphitized carbon black (Carbopak C or equivalent),
surface of approximately 12 m^/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 - Pallflex 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^.
-------
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
13C12-2,3,7,8-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 Assurancie 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
13,
o
o
3C12-2,3,7,8-TCDD
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)
o 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.
-------
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 (13C12-2,3,7,8-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).
-------
T09-14
9.5 The PUF is placed into the glass sampling cartridge using poly-
ester gloves. The module is wrapped with hexane-rinsed aluminum
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.
-------
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 foil 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.
-------
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.
-------
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
0 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 N32S04/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").
-------
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 tn'decane 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
-------
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
•-vij'." erii 2fHfcto 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 _<1 second. The laboratory must not
perform any further analysis until it has been demon-
strated and documented that the criterion listed in
Section 12.1.2 has been met.
12.3.4 Using the same GC (Section 12.1) and MS (Section 12.2)
conditions that produced acceptable results with the
column performance check solution, analyze a 2-uL
aliquot of each of the 5 concentration calibration
solutions in triplicate with the gas chromatographic
operating parameters shown in Table 2.
12.3.4.1 Total cycle time for data acquisition must
be <1 second. Total cycle time includes
the sum of all the dwell times and voltage
reset times.
-------
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,
13C12-132,3,4-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)3 relative to
13C12-2,3,7,8-TCDD and for labeled 13C12-
2,3,7,8-TCDD [RRF(II)] relative to 13C12-
1,2,3,4-TCDD as follows:
A • QTS
RRF(D = _________
RRF(II)=
AIS
AIS ' QRS
'IS " RS
-------
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.
QIS = 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 13Cl2-2,3,7,8-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 XLO 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-TCDD5 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
258.930
319.897
321.894
331.937
333.934
Compound
TCDD - COC1 (weak at
unlabeled
unlabeled
13C12-2,3
13C _2js
TCDD
TCDD
,7,8-TCDD,
,7,8-TCDD,
detection limit level)
13C12-1S2,3,4-TCDD,
13r _i ? •? 4_Trnn
19 •L»£-5J5M' ll»UL/,
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
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:
Ay ' QTC
~ A J.O
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 13C12-2,3S7S8-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 13C12-233,738-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 ^C-j ~-2., 3,7,8
TCDD, measured in the sample extract, using the formula:
IS " RS
Internal standard, _ x 100
percent recovery = ___
ARS • RRF(II) • QIS
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 ^C^-
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 GX be-
coming the concentration of any unlabeled TCDD isomer.
14.4 Estimated Detection Limit
14.4.1 For samples in which no un labeled 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) • (Ax) • (QIS)
CE =
(AIS) • RRF(I) • (W)
-------
T09-29
where:
Cg = 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 2.25 scans used to measure AI$.
= sum of integrated ion abundance for the appropriate ion
characteristic of the internal standard, m/z 331.937 and
m/z 333.934.
' RRFU); «>nd 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
x 100
(Si + S2)/2
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! + Q2 ••- QN T
Vm= x
_ _
N. TOOO
where:
Vm = total sample volume
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:
Vs =
_
760
298
273 +
where:
Vs = total sample volume (m3) at 25°C and 760 mm Hg pressure.
V = 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 VE
where:
C. = concentration (ug/m3) of analyte in the sample.
A = calculated amount of material determined by HRGC/HRMS.
V-j = 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
13r -i
L12-i,
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 13C12-2,3,758-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 um 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
-------
T09-34
O
<
LU
X
CD
Ij
CL
:>
<
CO
LU
cc
u_
-------
T09-35
Magnehelic
Gauge
0-100 in.
Exhaust
Duct
(6 in. x 10ft)
Sampling
Head
(See Figure 2)
\
Pipe Fitting (1/2 in.)
Voltage Variator
Elapsed Time Meter
FIGURE 2. HIGH VOLUME AIR SAMPLER
GENERAL METAL WORKS (MODEL PS-1)
-------
T09-36
o
o
QJ
3
4->
re
QJ
O.
OJ
4J
C
CD
•i—
XI
E
«=C
00
C-
c
4-» oo re
QJ «*v
CQ -a
QJ re o
O i—
ecu.
O) O
t- T- T-
<*- re 3
•r- XI C
Q -I- QJ
**
re
I ^
t- re
a) a
E «-
re 3
OO 4->
(U
(U
u
JJI
•r-
£_
O
f*7
o re
•r- 4->
•i— 3 ro
re o
£_
X)
•r~
^~
re
<~>
0
re c
s ^
0 E
i— O
u. to
•s
o
'?— o
QJ C
_f— — p-
QJ
C •
re -i-
QJre
re c:
a: T-
E
o "E"
i — O
U- to
A
£_
QJ O
4-> O
Q) m
E
C C
re T-
s:
o-
0 0
t_ ~x.
CD CO
E QJ
•r- >-
1—
o cn
re c
(- 4->
re 4->
>• ai
oo
c_
0)
Q.Z
re oo
oo
i
i
OJ
4-5
re
o
o
a;
u
CD
re
o
a>
jQ
3 •
I— -M
t- 3
3
yj
UJ
3C
CO
<
K-
o re
•r- OJ
CD
O 3
•r- I—
4-J
re T-
XI 3
•r- 4->
r— C
re CD
o >
L_ L.
O O
to co
a> CD
re re
c c
o o
X) XI
re re
o o
re xi
CL
CO
LU
J
CL
X
LU
LU
CC
-------
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 (~ I.Og)
SODIUM SULFATE/POTASSIUM CARBONATE (1:1)
GLASS WOOL PLUG
(b) SILICA GEL COLUMN
FIGURE 4. MULTILAYERED EXTRACT CLEANUP COLUMNS
U.S. GOVERNMENT PRINTING OFFICE : 1987-748-121/40692
-------
------- |