Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air Second Edition Compendium Method TO-15 Determination of Volatile Organic Compounds (VOCs) in Air Collected in Specially Prepared Canisters and Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS)


EPA/625/R-96/01 Ob

Compendium of Methods for the
Determination of Toxic Organic
Compounds in Ambient Air

Second Edition

Compendium Method TO-15

Determination of Volatile Organic Compounds (VOCs) in Air
Collected in Specially Prepared Canisters and Analyzed by Gas
Chromatography/Mass Spectrometry (GC/MS)

Center for Environmental Research Information
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268

January 1999

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Acknowledgements

This method was prepared for publication in the Compendium of Methods for the Determination of Toxic
Organic Compounds in Ambient Air, Second Edition (EPA/625/R-96/010b), under Contract No. 68-C3-
0315, WA No. 3-10, by Midwest Research Institute (MRI), as a subcontractor to Eastern Research Group,
Inc. (ERG), and under the sponsorship of the U.S. Environmental Protection Agency (EPA). Justice A.
Manning, John O. Burckle, and Scott Hedges of the Center for Environmental Research Information
(CERI) and Frank F. McElroy of the National Exposure Research Laboratory (NERL), all in the EPA Office
of Research and Development, were responsible for overseeing the preparation of this method. Additional
support was provided by other members of the Compendia Workgroup, which include the following:

John O. Burckle, EPA, ORD, Cincinnati, OH
James L. Cheney, Corps of Engineers, Omaha, NB
Michael Davis, U.S. EPA, Region 7, KC, KS
Joseph B. Elkins Jr., U.S. EPA, OAQPS, RTP, NC
Robert G. Lewis, U.S. EPA, NERL, RTP, NC
Justice A. Manning, U.S. EPA, ORD, Cincinnati, OH
William A. McClenny, U.S. EPA, NERL, RTP, NC
Frank F. McElroy, U.S. EPA, NERL, RTP, NC
Heidi Schultz, ERG, Lexington, MA

William T. "Jerry" Winberry, Jr., EnviroTech Solutions, Cary, NC

This method is the result of the efforts of many individuals. Gratitude goes to each person involved in
the preparation and review of this methodology.

Authors

William A. McClenny, EPA, NERL, RTP, NC
Michael W. Holdren, Battelle, Columbus, OH

Peer Reviewers

Karen Oliver, ManTech, RTP, NC

Jim Cheney, Corps of Engineers, Omaha, NB

Elizabeth Almasi, Varian Chromatography Systems, Walnut Creek, CA

Norm Kirshen, Varian Chromatography Systems, Walnut Creek, CA

Richard Jesser, Graseby, Smyrna, GA

Bill Taylor, Graseby, Smyrna, GA

Lauren Drees, EPA, NRMRL, Cincinnati, OH

Finally, recognition is given to Frances Beyer, Lynn Kaufman, Debbie Bond, Cathy Whitaker, and Kathy
Johnson of MRI's Administrative Services staff whose dedication and persistence during the
development of this manuscript has enabled its production.

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1	Disclaimer

2	This Compendium has been subjected to the Agency's peer and administrative review, and it has been

3	approved for publication as an EPA document. Mention of trade names or commercial products does

4	not constitute endorsement or recommendation for use.

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1	Contents

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t. Scope

1.1 This method documents sampling and analytical procedures for the measurement of subsets of the
97 volatile organic compounds (VOCs) that are included in the 189 hazardous air pollutants (HAPs) listed
in Title III of the Clean Air Act Amendments of 1990. VOCs are defined here as organic compounds
having a vapor pressure greater than 10-1 Torr at 25°C and 760 mm Hg. Table 1 is the list of the target
VOCs along with their CAS number, boiling point, vapor pressure and an indication of their membership
in both the list of VOCs covered by Compendium Method TO-14A (1) and the list of VOCs in EPA's
Contract Laboratory Program (CLP) document titled Statement-of-Work (SOW) for the Analysis of Air
Toxics from Superfund Sites (2).

Many of these compounds have been tested for stability in concentration when stored in specially-
prepared canisters (see Section 8) under conditions typical of those encountered in routine ambient air
analysis. The stability of these compounds under all possible conditions is not known. However, a model
to predict compound losses due to physical adsorption of VOCs on canister walls and to dissolution of
VOCs in water condensed in the canisters has been developed (3). Losses due to physical adsorption
require only the establishment of equilibrium between the condensed and gas phases and are generally
considered short term losses, (i.e., losses occurring over minutes to hours). Losses due to chemical
reactions of the VOCs with co-collected ozone or other gas phase species also account for some short
term losses. Chemical reactions between VOCs and substances inside the canister are generally
assumed to cause the gradual decrease of concentration overtime (i.e., long term losses over days to
weeks). Loss mechanisms such as aqueous hydrolysis and biological degradation (4) also exist. No
models are currently known to be available to estimate and characterize all these potential losses,
although a number of experimental observations are referenced in Section 8. Some of the VOCs listed in
Title III have short atmospheric lifetimes and may not be present except near sources.

1.2 This method applies to ambient concentrations of VOCs above 0.5 ppbv and typically requires VOC
enrichment by concentrating up to one liter of a sample volume. The VOC concentration range for
ambient air in many cases includes the concentration at which continuous exposure over a lifetime is
estimated to constitute a 10-6 or higher lifetime risk of developing cancer in humans. Under
circumstances in which many hazardous VOCs are present at 10-6 risk concentrations, the total risk may
be significantly greater.

1.3 This method applies under most conditions encountered in sampling of ambient air into canisters.
However, the composition of a gas mixture in a canister, under unique or unusual conditions, will change
so that the sample is known not to be a true representation of the ambient air from which it was taken. For
example, low humidity conditions in the sample may lead to losses of certain VOCs on the canister walls,
losses that would not happen if the humidity were higher. If the canister is pressurized, then condensation
of water from high humidity samples may cause fractional losses of water-soluble compounds. Since the
canister surface area is limited, all gases are in competition for the available active sites. Hence an
absolute storage stability cannot be assigned to a specific gas. Fortunately, under conditions of normal
usage for sampling ambient air, most VOCs can be recovered from canisters near their original
concentrations after storage times of up to thirty days (see Section 8).

1.4 Use of the Compendium Method TO-15 for many of the VOCs listed in Table 1 is likely to present two
difficulties: (1) what calibration standard to use for establishing a basis for testing and quantitation, and
(2) how to obtain an audit standard. In certain cases a chemical similarity exists between a thoroughly
tested compound and others on the Title III list. In this case, what works for one is likely to work for the

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1 other in terms of making standards. However, this is not always the case and some compound standards

2 will be troublesome. The reader is referred to the Section 9.2 on standards for guidance. Calibration of

3 compounds such as formaldehyde, diazomethane, and many of the others represents a challenge.

4 1.5 Compendium Method TO-15 should be considered for use when a subset of the 97 Title III VOCs

5 constitute the target list. Typical situations involve ambient air testing associated with the permitting

6 procedures for emission sources. In this case sampling and analysis of VOCs is performed to determine

7 the impact of dispersing source emissions in the surrounding areas. Other important applications are

8 prevalence and trend monitoring for hazardous VOCs in urban areas and risk assessments downwind of

9 industrialized or source-impacted areas.

10 1.6 Solid adsorbents can be used in lieu of canisters for sampling of VOCs, provided the solid adsorbent

11 packings, usually multisorbent packings in metal or glass tubes, can meet the performance criteria

12 specified in Compendium Method TO-17 which specifically addresses the use of multisorbent packings.

13 The two sample collection techniques are different but become the same upon movement of the sample

14 from the collection medium (canister or multisorbent tubes) onto the sample concentrator. Sample

15 collection directly from the atmosphere by automated gas chromatographs can be used in lieu of

16 collection in canisters or on solid adsorbents.

18 2. Summary of Method

19 2.1 The atmosphere is sampled by introduction of air into a specially-prepared stainless steel canister.

20 Both subatmospheric pressure and pressurized sampling modes use an initially evacuated canister. A

21 pump ventilated sampling line is used during sample collection with most commercially available

22 samplers. Pressurized sampling requires an additional pump to provide positive pressure to the sample

23 canister. A sample of air is drawn through a sampling train comprised of components that regulate the

24 rate and duration of sampling into the pre-evacuated and passivated canister.

25 2.2 After the air sample is collected, the canister valve is closed, an identification tag is attached to the

26 canister, and the canister is transported to the laboratory for analysis.

27 2.3 Upon receipt at the laboratory, the canister tag data is recorded and the canister is stored until

28 analysis. Storage times of up to thirty days have been demonstrated for many of the VOCs (5).

29 2.4 To analyze the sample, a known volume of sample is directed from the canister through a solid

30 multisorbent concentrator. A portion of the water vapor in the sample breaks through the concentrator

31 during sampling, to a degree depending on the multisorbent composition, duration of sampling, and other

32 factors. Water content of the sample can be further reduced by dry purging the concentrator with helium

33 while retaining target compounds. After the concentration and drying steps are completed, the VOCs are

34 thermally desorbed, entrained in a carrier gas stream, and then focused in a small volume by trapping on

35 a reduced temperature trap or small volume multisorbent trap. The sample is then released by thermal

36 desorption and carried onto a gas chromatographic column for separation.

37 As a simple alternative to the multisorbent/dry purge water management technique, the amount of water

38 vapor in the sample can be reduced below any threshold for affecting the proper operation of the

39 analytical system by reducing the sample size. For example, a small sample can be concentrated on a

40 cold trap and released directly to the gas chromatographic column. The reduction in sample volume may

41 require an enhancement of detector sensitivity.

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Other water management approaches are also acceptable as long as their use does not compromise the
attainment of the performance criteria listed in Section 11. A listing of some commercial water
management systems is provided in Appendix A. One of the alternative ways to dry the sample is to
separate VOCs from condensate on a low temperature trap by heating and purging the trap.

2.5 The analytical strategy for Compendium Method TO-15 involves using a high resolution gas
chromatograph (GC) coupled to a mass spectrometer. If the mass spectrometer is a linear quadrupole
system, it is operated either by continuously scanning a wide range of mass to charge ratios (SCAN
mode) or by monitoring select ion monitoring mode (SIM) of compounds on the target list. If the mass
spectrometer is based on a standard ion trap design, only a scanning mode is used (note, however, that
the selected ion storage (SIS) mode for the ion trap has features of the SIM mode). Mass spectra for
individual peaks in the total ion chromatogram are examined with respect to the fragmentation pattern of
ions corresponding to various VOCs including the intensity of primary and secondary ions. The
fragmentation pattern is compared with stored spectra taken under similar conditions, in order to identify
the compound. For any given compound, the intensity of the primary fragment is compared with the
system response to the primary fragment for known amounts of the compound. This establishes the
compound concentration that exists in the sample.

Mass spectrometry is considered a more definitive identification technique than single specific detectors
such as flame ionization detector (FID), electron capture detector (ECD), photoionization detector (PID),
or a multidetector arrangement of these (see discussion in Compendium Method TO-14A). The use of
both gas chromatographic retention time and the generally unique mass fragmentation patterns reduce
the chances for misidentification. If the technique is supported by a comprehensive mass spectral
database and a knowledgeable operator, then the correct identification and quantification of VOCs is
further enhanced.

3. Significance

3.1 Compendium Method TO-15 is significant in that it extends the Compendium Method TO-14A
description for using canister-based sampling and gas chromatographic analysis in the following ways:

• Compendium Method TO-15 incorporates a multisorbent/dry purge technique or equivalent (see
Appendix A) for water management thereby addressing a more extensive set of compounds (the
VOCs mentioned in Title III of the CAAA of 1990) than addressed by Compendium Method TO-
14A. Compendium Method TO-14A approach to water management alters the structure or
reduces the sample stream concentration of some VOCs, especially water-soluble VOCs.

• Compendium Method TO-15 uses the GC/MS technique as the only means to identify and
quantitate target compounds. The GC/MS approach provides a more scientifically-defensible
detection scheme which is generally more desirable than the use of single or even multiple
specific detectors.

• In addition, Compendium Method TO-15 establishes method performance criteria for acceptance
of data, allowing the use of alternate but equivalent sampling and analytical equipment. There are
several new and viable commercial approaches for water management as noted in Appendix A of
this method on which to base a VOC monitoring technique as well as other approaches to
sampling (i.e., autoGCs and solid to be acceptable alternatives for monitoring ambient VOCs.

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• Finally, Compendium Method TO-15 includes enhanced provisions for inherent quality control.
The method uses internal analytical standards and frequent verification of analytical system
performance to assure control of the analytical system. This more formal and better documented
approach to quality control guarantees a higher percentage of good data.

3.2 With these features, Compendium Method TO-15 is a more general yet better defined method for
VOCs than Compendium Method TO-14A. As such, the method can be applied with a higher confidence
to reduce the uncertainty in risk assessments in environments where the hazardous volatile gases listed
in the Title III of the Clean Air Act Amendments of 1990 are being monitored. An emphasis on risk
assessments for human health and effects on the ecology is a current goal for the U.S. EPA.

4. Applicable Documents

4.1 ASTM Standards

• Method D1356 Definitions of Terms Relating to Atmospheric Sampling and Analysis.

• Method E260 Recommended Practice for General Gas Chromatography Procedures.

• Method E355 Practice for Gas Chromatography Terms and Relationships.

• Method D5466 Standard Test Method of Determination of Volatile Organic Compounds in
Atmospheres (Canister Sampling Methodology).

4.2 EPA Documents

• Quality Assurance Handbook for Air Pollution Measurement Systems, Volume II, U. S.
Environmental Protection Agency, EPA-600/R-94-038b, May 1994.

• Technical Assistance Document for Sampling and Analysis of Toxic Organic Compounds in
Ambient Air, U. S. Environmental Protection Agency, EPA-600/4-83-027, June 1983.

• Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air:
Method TO-14, Second Supplement, U. S. Environmental Protection Agency, EPA-600/4-89-018,
March 1989.

• Statement-of-Work (SOW) for the Analysis of Air Toxics from Superfund Sites, U. S.
Environmental Protection Agency, Office of Solid Waste, Washington, D.C., Draft Report, June
1990.

• Clean Air Act Amendments of 1990, U. S. Congress, Washington, D.C., November 1990.

5. Definitions

[Note: Definitions used in this document and any user-prepared standard operating procedures (SOPs)
should be consistent with ASTM Methods D1356, E260, and E355. Aside from the definitions given
below, all pertinent abbreviations and symbols are defined within this document at point of use.]

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1 5.1 Gauge Pressure—pressure measured with reference to the surrounding atmospheric pressure,

2 usually expressed in units of kPa or psi. Zero gauge pressure is equal to atmospheric (barometric)

3 pressure.

4 5.2 Absolute Pressure—pressure measured with reference to absolute zero pressure, usually

5 expressed in units of kPa, or psi.

6 5.3 Cryogen—a refrigerant used to obtain sub-ambient temperatures in the VOC concentrator and/or on

7 front of the analytical column. Typical cryogens are liquid nitrogen (bp -195.8°C), liquid argon (bp -

8 185.7°C), and liquid C02 (bp -79.5°C).

9 5.4 Dynamic Calibration—calibration of an analytical system using calibration gas standard

10 concentrations in a form identical or very similar to the samples to be analyzed and by introducing such

11 standards into the inlet of the sampling or analytical system from a manifold through which the gas

12 standards are flowing.

13 5.5 Dynamic Dilution—means of preparing calibration mixtures in which standard gas(es) from

14 pressurized cylinders are continuously blended with humidified zero air in a manifold so that a flowing

15 stream of calibration mixture is available at the inlet of the analytical system.

16 5.6 MS-SCAN—mass spectrometric mode of operation in which the gas chromatograph (GC) is coupled

17 to a mass spectrometer (MS) programmed to SCAN all ions repeatedly over a specified mass range.

18 5.7 MS-SIM—mass spectrometric mode of operation in which the GC is coupled to a MS that is

19 programmed to scan a selected number of ions repeatedly [i.e., selected ion monitoring (SIM) mode],

20 5.8 Qualitative Accuracy—the degree of measurement accuracy required to correctly identify

21 compounds with an analytical system.

22 5.9 Quantitative Accuracy—the degree of measurement accuracy required to correctly measure the

23 concentration of an identified compound with an analytical system with known uncertainty.

24 5.10 Replicate Precision—precision determined from two canisters filled from the same air mass over

25 the same time period and determined as the absolute value of the difference between the analyses of

26 canisters divided by their average value and expressed as a percentage (see Section 11 for performance

27 criteria for replicate precision).

28 5.11 Duplicate Precision—precision determined from the analysis of two samples taken from the same

29 canister. The duplicate precision is determined as the absolute value of the difference between the

30 canister analyses divided by their average value and expressed as a percentage.

31 5.12 Audit Accuracy—the difference between the analysis of a sample provided in an audit canister and

32 the nominal value as determined by the audit authority, divided by the audit value and expressed as a

33 percentage (see Section 11 for performance criteria for audit accuracy).

35 6. Interferences and Contamination

36 6.1 Very volatile compounds, such as chloromethane and vinyl chloride can display peak broadening and

37 co-elution with other species if the compounds are not delivered to the GC column in a small volume of

38 carrier gas. Refocusing of the sample after collection on the primary trap, either on a separate focusing

39 trap or at the head of the gas chromatographic column, mitigates this problem.

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6.2 Interferences in canister samples may result from improper use or from contamination of: (1) the
canisters due to poor manufacturing practices, (2) the canister cleaning apparatus, and (3) the sampling
or analytical system. Attention to the following details will help to minimize the possibility of contamination
of canisters.

6.2.1 Canisters should be manufactured using high quality welding and cleaning techniques, and new
canisters should be filled with humidified zero air and then analyzed, after "aging" for 24 hours, to
determine cleanliness. The cleaning apparatus, sampling system, and analytical system should be
assembled of clean, high quality components and each system should be shown to be free of
contamination.

6.2.2 Canisters should be stored in a contaminant-free location and should be capped tightly during
shipment to prevent leakage and minimize any compromise of the sample.

6.2.3 Impurities in the calibration dilution gas (if applicable) and carrier gas, organic compounds out-
gassing from the system components ahead of the trap, and solvent vapors in the laboratory account
for the majority of contamination problems. The analytical system must be demonstrated to be free
from contamination under the conditions of the analysis by running humidified zero air blanks. The
use of non-chromatographic grade stainless steel tubing, non-PTFE thread sealants, or flow
controllers with Buna-N rubber components must be avoided.

6.2.4 Significant contamination of the analytical equipment can occur whenever samples containing
high VOC concentrations are analyzed. This in turn can result in carryover contamination in
subsequent analyses. Whenever a high concentration (>25 ppbv of a trace species) sample is
encountered, it should be followed by an analysis of humid zero air to check for carry-over
contamination.

6.2.5 In cases when solid sorbents are used to concentrate the sample prior to analysis, the sorbents
should be tested to identify artifact formation (see Compendium Method TO-17 for more information
on artifacts).

7. Apparatus and Reagents

[Note: Compendium Method To-14A list more specific requirements for sampling and analysis apparatus
which may be of help in identifying options. The listings below are generic.]

7.1 Sampling Apparatus

[Note: Subatmospheric pressure and pressurized canister sampling systems are commercially available
and have been used as part of U.S. Environmental Protection Agency's Toxic Air Monitoring Stations
(TAMS), Urban Air Toxic Monitoring Program (UATMP), the non-methane organic compound (NMOC)
sampling and analysis program, and the Photochemical Assessment Monitoring Stations (PAMS).]

7.1.1 Subatmospheric Pressure (see Figure 1, without metal bellows type pump).

7.1.1.1 Sampling Inlet Line. Stainless steel tubing to connect the sampler to the sample inlet.

7.1.1.2 Sample Canister. Leak-free stainless steel pressure vessels of desired volume (e.g., 6
L), with valve and specially prepared interior surfaces (see Appendix B for a listing of known
manufacturers/resellers of canisters).

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7.1.1.3 Stainless Steel Vacuum/Pressure Gauges. Two types are required, one capable of
measuring vacuum (-100 to 0 kPa or 0 to - 30 in Hg) and pressure (0-206 kPa or 0-30 psig) in
the sampling system and a second type (for checking the vacuum of canisters during cleaning)
capable of measuring at 0.05 mm Hg (see Appendix B) within 20%. Gauges should be tested
clean and leak tight.

7.1.1.4 Electronic Mass Flow Controller. Capable of maintaining a constant flow rate (± 10%)
over a sampling period of up to 24 hours and under conditions of changing temperature (20-
40°C) and humidity.

7.1.1.5 Particulate Matter Filter. 2-|jm sintered stainless steel in-line filter.

7.1.1.6 Electronic Timer. For unattended sample collection.

7.1.1.7 Solenoid Valve. Electrically operated, bi-stable solenoid valve with Viton® seat and O-
rings. A Skinner Magnelatch valve is used for purposes of illustration in the text (see Figure 2).

7.1.1.8 Chromatographic Grade Stainless Steel Tubing and Fittings. For interconnections. All
such materials in contact with sample, analyte, and support gases prior to analysis should be
chromatographic grade stainless steel or equivalent.

7.1.1.9 Thermostatically Controlled Heater. To maintain above ambient temperature inside
insulated sampler enclosure.

7.1.1.10 Heater Thermostat. Automatically regulates heater temperature.

7.1.1.11 Fan. For cooling sampling system.

7.1.1.12 Fan Thermostat. Automatically regulates fan operation.

7.1.1.13 Maximum-Minimum Thermometer. Records highest and lowest temperatures during
sampling period.

7.1.1.14 Stainless Steel Shut-off Valve. Leak free, for vacuum/pressure gauge.

7.1.1.15 Auxiliary Vacuum Pump. Continuously draws air through the inlet manifold at 10 L/min.
or higher flow rate. Sample is extracted from the manifold at a lower rate, and excess air is
exhausted.

[Note: The use of higher inlet flow rates dilutes any contamination present in the inlet and reduces
the possibility of sample contamination as a result of contact with active adsorption sites on inlet
walls.]

7.1.1.16 Elapsed Time Meter. Measures duration of sampling.

7.1.1.17 Optional Fixed Orifice, Capillary, or Adjustable Micrometering Valve. May be used
in lieu of the electronic flow controller for grab samples or short duration time-integrated samples.
Usually appropriate only in situations where screening samples are taken to assess future
sampling activity.

7.1.2 Pressurized (see Figure 1 with metal bellows type pump and Figure 3).

7.1.2.1 Sample Pump. Stainless steel, metal bellows type, capable of 2 atmospheres output
pressure. Pump must be free of leaks, clean, and uncontaminated by oil or organic compounds.

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[Note: An alternative sampling system has been developed by Dr. R. Rasmussen, The Oregon
Graduate Institute of Science and Technology, 20000 N.W. Walker Rd., Beaverton, Oregon
97006, 503-690-1077, and is illustrated in Figure 3. This flow system uses, in order, a pump, a
mechanical flow regulator, and a mechanical compensation flow restrictive device. In this
configuration the pump is purged with a large sample flow, thereby eliminating the need for an
auxiliary vacuum pump to flush the sample inlet.]

7.1.2.2 Other Supporting Materials. All other components of the pressurized sampling system
are similar to components discussed in Sections 7.1.1.1 through 7.1.1.17.

7.2 Analytical Apparatus

7.2.1 Sampling/Concentrator System (many commercial alternatives are available).

7.2.1.1 Electronic Mass Flow Controllers. Used to maintain constant flow (for purge gas, carrier
gas and sample gas) and to provide an analog output to monitor flow anomalies.

7.2.1.2 Vacuum Pump. General purpose laboratory pump, capable of reducing the downstream
pressure of the flow controller to provide the pressure differential necessary to maintain controlled
flow rates of sample air.

7.2.1.3 Stainless Steel Tubing and Stainless Steel Fittings. Coated with fused silica to
minimize active adsorption sites.

7.2.1.4 Stainless Steel Cylinder Pressure Regulators. Standard, two-stage cylinder regulators
with pressure gauges.

7.2.1.5 Gas Purifiers. Used to remove organic impurities and moisture from gas streams.

7.2.1.6 Six-port Gas Chromatographic Valve. For routing sample and carrier gas flows.

7.2.1.7 Multisorbent Concentrator. Solid adsorbent packing with various retentive properties for
adsorbing trace gases are commercially available from several sources. The packing contains
more than one type of adsorbent packed in series.

7.2.1.7.1 A pre-packed adsorbent trap (Supelco 2-0321) containing 200 mg Carbopack B
(60/80 mesh) and 50 mg Carbosieve S-lll (60/80 mesh) has been found to retain VOCs and
allow some water vapor to pass through (6). The addition of a dry purging step allows for
further water removal from the adsorbent trap. The steps constituting the dry purge technique
that are normally used with multisorbent traps are illustrated in Figure 4. The optimum
trapping and dry purging procedure for the Supelco trap consists of a sample volume of 320
mL and a dry nitrogen purge of 1300 mL. Sample trapping and drying is carried out at 25°C.
The trap is back-flushed with helium and heated to 220°C to transfer material onto the GC
column. A trap bake-out at 260°C for 5 minutes is conducted after each run.

7.2.1.7.2 An example of the effectiveness of dry purging is shown in Figure 5. The
multisorbent used in this case is Ten ax/Am be rsorb 340/Charcoal (7). Approximately 20% of
the initial water content in the sample remains after sampling 500 mL of air. The detector
response to water vapor (hydrogen atoms detected by atomic emission detection) is plotted
versus purge gas volume. Additional water reduction by a factor of 8 is indicated at
temperatures of 45°C or higher. Still further water reduction is possible using a two-stage
concentration/dryer system.

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7.2.1.8 Cryogenic Concentrator. Complete units are commercially available from several vendor
sources. The characteristics of the latest concentrators include a rapid, "ballistic" heating of the
concentrator to release any trapped VOCs into a small carrier gas volume. This facilitates the
separation of compounds on the gas chromatographic column.

7.2.2 Gas Chromatographic/Mass Spectrometric (GC/MS) System.

7.2.2.1 Gas Chromatograph. The gas chromatographic (GC) system must be capable of
temperature programming. The column oven can be cooled to subambient temperature (e.g., -
50°C) at the start of the gas chromatographic run to effect a resolution of the very volatile organic
compounds. In other designs, the rate of release of compounds from the focusing trap in a two
stage system obviates the need for retrapping of compounds on the column. The system must
include or be interfaced to a concentrator and have all required accessories including analytical
columns and gases. All GC carrier gas lines must be constructed from stainless steel or copper
tubing. Non-polytetrafluoroethylene (PTFE) thread sealants or flow controllers with Buna-N rubber
components must not be used.

7.2.2.2 Chromatographic Columns. 100% methyl silicone or 5% phenyl, 95% methyl silicone
fused silica capillary columns of 0.25- to 0.53-mm I.D. of varying lengths are recommended for
separation of many of the possible subsets of target compounds involving nonpolar compounds.
However, considering the diversity of the target list, the choice is left to the operator subject to the
performance standards given in Section 11.

7.2.2.3 Mass Spectrometer. Either a linear quadrupole or ion trap mass spectrometer can be
used as long as it is capable of scanning from 35 to 300 amu every 1 second or less, utilizing 70
volts (nominal) electron energy in the electron impact ionization mode, and producing a mass
spectrum which meets all the instrument performance acceptance criteria when 50 ng or less of
p-bromofluorobenzene (BFB) is analyzed.

7.2.2.3.1 Linear Quadrupole Technology. A simplified diagram of the heart of the
quadrupole mass spectrometer is shown in Figure 6. The quadrupole consists of a parallel
set of four rod electrodes mounted in a square configuration. The field within the analyzer is
created by coupling opposite pairs of rods together and applying radiofrequency (RF) and
direct current (DC) potentials between the pairs of rods. Ions created in the ion source from
the reaction of column eluates with electrons from the electron source are moved through the
parallel array of rods under the influence of the generated field. Ions which are successfully
transmitted through the quadrupole are said to possess stable trajectories and are
subsequently recorded with the detection system. When the DC potential is zero, a wide
band of m/z values is transmitted through the quadrupole. This "RF only" mode is referred to
as the "total-ion" mode. In this mode, the quadrupole acts as a strong focusing lens
analogous to a high pass filter. The amplitude of the RF determines the low mass cutoff. A
mass spectrum is generated by scanning the DC and RF voltages using a fixed DC/RF ratio
and a constant drive frequency or by scanning the frequency and holding the DC and RF
constant. With the quadrupole system only 0.1 to 0.2 percent of the ions formed in the ion
source actually reach the detector.

7.2.2.3.2 Ion Trap Technology. An ion-trap mass spectrometer consists of a chamber
formed between two metal surfaces in the shape of a hyperboloid of one sheet (ring
electrode) and a hyperboloid of two sheets (the two end-cap electrodes). Ions are created

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within the chamber by electron impact from an electron beam admitted through a small
aperture in one of the end caps. Radio frequency (RF) (and sometimes direct current voltage
offsets) are applied between the ring electrode and the two end-cap electrodes establishing a
quadrupole electric field. This field is uncoupled in three directions so that ion motion can be
considered independently in each direction; the force acting upon an ion increases with the
displacement of the ion from the center of the field but the direction of the force depends on
the instantaneous voltage applied to the ring electrode. A restoring force along one
coordinate (such as the distance, r, from the ion-trap's axis of radial symmetry) will exist
concurrently with a repelling force along another coordinate (such as the distance, z, along
the ion traps axis), and if the field were static the ions would eventually strike an electrode.
However, in an RF field the force along each coordinate alternates direction so that a stable
trajectory may be possible in which the ions do not strike a surface. In practice, ions of
appropriate mass-to-charge ratios may be trapped within the device for periods of
milliseconds to hours. A diagram of a typical ion trap is illustrated in Figure 7. Analysis of
stored ions is performed by increasing the RF voltage, which makes the ions successively
unstable. The effect of the RF voltage on the ring electrode is to "squeeze" the ions in the xy
plane so that they move along the z axis. Half the ions are lost to the top cap (held at ground
potential); the remaining ions exit the lower end cap to be detected by the electron multiplier.
As the energy applied to the ring electrode is increased, the ions are collected in order of
increasing mass to produce a conventional mass spectrum. With the ion trap, approximately
50 percent of the generated ions are detected. As a result, a significant increase in sensitivity
can be achieved when compared to a full scan linear quadrupole system.

7.2.2.4 GC/MS Interface. Any gas chromatograph to mass spectrometer interface that gives
acceptable calibration points for each of the analytes of interest and can be used to achieve all
acceptable performance criteria may be used. Gas chromatograph to mass spectrometer
interfaces constructed of all-glass, glass-lined, or fused silica-lined materials are recommended.
Glass and fused silica should be deactivated.

7.2.2.5 Data System. The computer system that is interfaced to the mass spectrometer must
allow the continuous acquisition and storage, on machine readable media, of all mass spectra
obtained throughout the duration of the chromatographic program. The computer must have
software that allows searching any GC/MS data file for ions of a specified mass and plotting such
ion abundances versus time or scan number. This type of plot is defined as a Selected Ion
Current Profile (SICP). Software must also be available that allows integrating the abundance in
any SICP between specified time or scan number limits. Also, software must be available that
allows for the comparison of sample spectra with reference library spectra. The National Institute
of Standards and Technology (NIST) or Wiley Libraries or equivalent are recommended as
reference libraries.

7.2.2.6 Off-line Data Storage Device. Device must be capable of rapid recording and retrieval of
data and must be suitable for long-term, off-line data storage.

7.3 Calibration System and Manifold Apparatus (see Figure 8)

7.3.1 Calibration Manifold. Stainless steel, glass, or high purity quartz manifold, (e.g.,1,25-cm I.D. x
66-cm) with sampling ports and internal baffles for flow disturbance to ensure proper mixing. The
manifold should be heated to ~50°C.

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7.3.2 Humidifier. 500-mL impinger flask containing HPLC grade deionized water.

7.3.3 Electronic Mass Flow Controllers. One 0 to 5 L/min unit and one or more 0 to 100 mL/min
units for air, depending on number of cylinders in use for calibration.

7.3.4 Teflon Filter(s). 47-mm Teflon® filter for particulate collection.

7.4 Reagents

7.4.1 Neat Materials or Manufacturer-Certified Solutions/Mixtures. Best source (see Section 9).

7.4.2 Helium and Air. Ultra-high purity grade in gas cylinders. He is used as carrier gas in the GC.

7.4.3 Liquid Nitrogen or Liquid Carbon Dioxide. Used to cool secondary trap.

7.4.4 Deionized Water. High performance liquid chromatography (HPLC) grade, ultra-high purity (for
humidifier).

8. Collection of Samples in Canisters

8.1 Introduction

8.1.1 Canister samplers, sampling procedures, and canister cleaning procedures have not changed
very much from the description given in the original Compendium Method TO-14. Much of the
material in this section is therefore simply a restatement of the material given in Compendium Method
TO-14, repeated here in order to have all the relevant information in one place.

8.1.2 Recent notable additions to the canister technology has been in the application of canister-
based systems for example, to microenvironmental monitoring (8), the capture of breath samples (9),
and sector sampling to identify emission sources of VOCs (10).

8.1.3 EPA has also sponsored the development of a mathematical model to predict the storage
stability of arbitrary mixtures of trace gases in humidified air (3), and the investigation of the
SilcoSteel™ process of coating the canister interior with a film of fused silica to reduce surface
activity (11). A recent summary of storage stability data for VOCs in canisters is given in the open
literature (5).

8.2 Sampling System Description

8.2.1 Subatmospheric Pressure Sampling [see Figure 1 (without metal bellows type pump)].

8.2.1.1 In preparation for subatmospheric sample collection in a canister, the canister is
evacuated to 0.05 mm Hg (see Appendix C for discussion of evacuation pressure). When the
canister is opened to the atmosphere containing the VOCs to be sampled, the differential
pressure causes the sample to flow into the canister. This technique may be used to collect grab
samples (duration of 10 to 30 seconds) or time-weighted- average (TWA) samples (duration of 1-
24 hours) taken through a flow-restrictive inlet (e.g., mass flow controller, critical orifice).

8.2.1.2 With a critical orifice flow restrictor, there will be a decrease in the flow rate as the
pressure approaches atmospheric. However, with a mass flow controller, the subatmospheric
sampling system can maintain a constant flow rate from full vacuum to within about 7 kPa (1.0
psi) or less below ambient pressure.

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1 8.2.2 Pressurized Sampling [see Figure 1 (with metal bellows type pump)].

2 8.2.2.1 Pressurized sampling is used when longer-term integrated samples or higher volume

3 samples are required. The sample is collected in a canister using a pump and flow control

4 arrangement to achieve a typical 101-202 kPa (15-30 psig) final canister pressure. For example,

5 a 6-liter evacuated canister can be filled at 10 mL/min for 24 hours to achieve a final pressure of

6 144 kPa (21 psig).

7 8.2.2.2 In pressurized canister sampling, a metal bellows type pump draws in air from the

8 sampling manifold to fill and pressurize the sample canister.

9 8.2.3 All Samplers.

10 8.2.3.1 A flow control device is chosen to maintain a constant flow into the canister over the

11 desired sample period. This flow rate is determined so the canister is filled (to about 88.1 kPa for

12 subatmospheric pressure sampling or to about one atmosphere above ambient pressure for

13 pressurized sampling) over the desired sample period. The flow rate can be calculated by:

Px V

14 F= ——

T x 60

15 where:

16 F = flow rate, mL/min.

17 P = final canister pressure, atmospheres absolute. P is approximately equal to

kPa gauge

18 7KT~^~ + 1

101.2

19 V = volume of the canister, mL.

20 T = sample period, hours.

21 For example, if a 6-L canister is to be filled to 202 kPa (2 atmospheres) absolute pressure in

22 24 hours, the flow rate can be calculated by:

2 x 6000

23 F = ——— = 8.3 mL/min

24x60

24 8.2.3.2 For automatic operation, the timer is designed to start and stop the pump at appropriate

25 times for the desired sample period. The timer must also control the solenoid valve, to open the

26 valve when starting the pump and to close the valve when stopping the pump.

27 8.2.3.3 The use of the Skinner Magnelatch valve (see Figure 2) avoids any substantial

28 temperature rise that would occur with a conventional, normally closed solenoid valve that would

29 have to be energized during the entire sample period. The temperature rise in the valve could

30 cause outgassing of organic compounds from the Viton® valve seat material. The Skinner

31 Magnelatch valve requires only a brief electrical pulse to open or close at the appropriate start

32 and stop times and therefore experiences no temperature increase. The pulses may be obtained

33 either with an electronic timer that can be programmed for short (5 to 60 seconds) ON periods, or

34 with a conventional mechanical timer and a special pulse circuit. A simple electrical pulse circuit

35 for operating the Skinner Magnelatch solenoid valve with a conventional mechanical timer is

36 illustrated in Figure 2(a). However, with this simple circuit, the valve may operate unreliably

37 during brief power interruptions or if the timer is manually switched on and off too fast. A better

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circuit incorporating a time-delay relay to provide more reliable valve operation is shown in Figure
2(b).

8.2.3.4 The connecting lines between the sample inlet and the canister should be as short as
possible to minimize their volume. The flow rate into the canister should remain relatively
constant over the entire sampling period.

8.2.3.5 As an option, a second electronic timer may be used to start the auxiliary pump several
hours prior to the sampling period to flush and condition the inlet line.

8.2.3.6 Prior to field use, each sampling system must pass a humid zero air certification (see
Section 8.4.3). All plumbing should be checked carefully for leaks. The canisters must also pass a
humid zero air certification before use (see Section 8.4.1).

8.3 Sampling Procedure

8.3.1 The sample canister should be cleaned and tested according to the procedure in Section 8.4.1.

8.3.2 A sample collection system is assembled as shown in Figures 1 and 3 and must be cleaned
according to the procedure outlined in Sections 8.4.2 and 8.4.4.

[Note: The sampling system should be contained in an appropriate enclosure.]

8.3.3 Prior to locating the sampling system, the user may want to perform "screening analyses" using
a portable GC system, as outlined in Appendix B of Compendium Method TO-14A, to determine
potential volatile organics present and potential "hot spots." The information gathered from the
portable GC screening analysis would be used in developing a monitoring protocol, which includes
the sampling system location, based upon the "screening analysis" results.

8.3.4 After "screening analysis," the sampling system is located. Temperatures of ambient air and
sampler box interior are recorded on the canister sampling field test data sheet (FTDS), as
documented in Figure 9.

[Note: The following discussion is related to Figure 1]

8.3.5 To verify correct sample flow, a "practice" (evacuated) canister is used in the sampling system.

[Note: For a subatmospheric sampler, a flow meter and practice canister are needed. For the pump-
driven system, the practice canister is not needed, as the flow can be measured at the outlet of the
system.]

A certified mass flow meter is attached to the inlet line of the manifold, just in front of the filter. The
canister is opened. The sampler is turned on and the reading of the certified mass flow meter is
compared to the sampler mass flow controller. The values should agree within ±10%. If not, the
sampler mass flow meter needs to be recalibrated or there is a leak in the system. This should be
investigated and corrected.

[Note: Mass flow meter readings may drift. Check the zero reading carefully and add or subtract the
zero reading when reading or adjusting the sampler flow rate to compensate for any zero drift.]

After 2 minutes, the desired canister flow rate is adjusted to the proper value (as indicated by the
certified mass flow meter) by the sampler flow control unit controller (e.g., 3.5 mL/min for 24 hr, 7.0
mL/min for 12 hr). Record final flow under "CANISTER FLOW RATE" on the FTDS.

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8.3.6 The sampler is turned off and the elapsed time meter is reset to 000.0.

[Note: Whenever the sampler is turned off, wait at least 30 seconds to turn the sampler back on.]

8.3.7 The "practice" canister and certified mass flow meter are disconnected and a clean certified
(see Section 8.4.1) canister is attached to the system.

8.3.8 The canister valve and vacuum/pressure gauge valve are opened.

8.3.9 Pressure/vacuum in the canister is recorded on the canister FTDS (see Figure 9) as indicated
by the sampler vacuum/pressure gauge.

8.3.10 The vacuum/pressure gauge valve is closed and the maximum-minimum thermometer is reset
to current temperature. Time of day and elapsed time meter readings are recorded on the canister
FTDS.

8.3.11 The electronic timer is set to start and stop the sampling period at the appropriate times.
Sampling starts and stops by the programmed electronic timer.

8.3.12 After the desired sampling period, the maximum, minimum, current interior temperature and
current ambient temperature are recorded on the FTDS. The current reading from the flow controller
is recorded.

8.3.13 At the end of the sampling period, the vacuum/pressure gauge valve on the sampler is briefly
opened and closed and the pressure/vacuum is recorded on the FTDS. Pressure should be close to
desired pressure.

[Note: For a subatmospheric sampling system, if the canister is at atmospheric pressure when the
field final pressure check is performed, the sampling period may be suspect. This information should
be noted on the sampling field data sheet.]

Time of day and elapsed time meter readings are also recorded.

8.3.14 The canister valve is closed. The sampling line is disconnected from the canister and the
canister is removed from the system. For a subatmospheric system, a certified mass flow meter is
once again connected to the inlet manifold in front of the in-line filter and a "practice" canister is
attached to the Magnelatch valve of the sampling system. The final flow rate is recorded on the
canister FTDS (see Figure 9).

[Note: For a pressurized system, the final flow may be measured directly.]

The sampler is turned off.

8.3.15 An identification tag is attached to the canister. Canister serial number, sample number,
location, and date, as a minimum, are recorded on the tag. The canister is routinely transported back
to the analytical laboratory with other canisters in a canister shipping case.

8.4 Cleaning and Certification Program

8.4.1 Canister Cleaning and Certification.

8.4.1.1 All canisters must be clean and free of any contaminants before sample collection.

8.4.1.2 All canisters are leak tested by pressurizing them to approximately 206 kPa (30 psig) with
zero air.

[Note: The canister cleaning system in Figure 10 can be used for this task.]

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The initial pressure is measured, the canister valve is closed, and the final pressure is checked
after 24 hours. If acceptable, the pressure should not vary more than ± 13.8 kPa (± 2 psig) over
the 24 hour period.

8.4.1.3 A canister cleaning system may be assembled as illustrated in Figure 10. Cryogen is
added to both the vacuum pump and zero air supply traps. The canister(s) are connected to the
manifold. The vent shut-off valve and the canister valve(s) are opened to release any remaining
pressure in the canister(s). The vacuum pump is started and the vent shut-off valve is then closed
and the vacuum shut-off valve is opened. The canister(s) are evacuated to <0.05 mm Hg (see
Appendix B) for at least 1 hour.

[Note: On a daily basis or more often if necessary, the cryogenic traps should be purged with zero
air to remove any trapped water from previous canister cleaning cycles.]

Air released/evacuated from canisters should be diverted to a fume hood.

8.4.1.4 The vacuum and vacuum/pressure gauge shut-off valves are closed and the zero air shut-
off valve is opened to pressurize the canister(s) with humid zero air to approximately 206 kPa (30
psig). If a zero gas generator system is used, the flow rate may need to be limited to maintain the
zero air quality.

8.4.1.5 The zero air shut-off valve is closed and the canister(s) is allowed to vent down to
atmospheric pressure through the vent shut-off valve. The vent shut-off valve is closed. Repeat
Sections 8.4.1.3 through 8.4.1.5 two additional times for a total of three (3)
evacuation/pressurization cycles for each set of canisters.

8.4.1.6 At the end of the evacuation/pressurization cycle, the canister is pressurized to 206 kPa
(30 psig) with humid zero air. The canister is then analyzed by a GC/MS analytical system. Any
canister that has not tested clean (compared to direct analysis of humidified zero air of less than
0.2 ppbv of targeted VOCs) should not be used. As a "blank" check of the canister(s) and cleanup
procedure, the final humid zero air fill of 100% of the canisters is analyzed until the cleanup
system and canisters are proven reliable (less than 0.2 ppbv of any target VOCs). The check can
then be reduced to a lower percentage of canisters.

8.4.1.7 The canister is reattached to the cleaning manifold and is then reevacuated to <0.05 mm
Hg (see Appendix B) and remains in this condition until used. The canister valve is closed. The
canister is removed from the cleaning system and the canister connection is capped with a
stainless steel fitting. The canister is now ready for collection of an air sample. An identification
tag is attached to the inlet of each canister for field notes and chain-of-custody purposes. An
alternative to evacuating the canister at this point is to store the canisters and reevacuate them
just prior to the next use.

8.4.1.8 As an option to the humid zero air cleaning procedures, the canisters are heated in an
isothermal oven not to exceed 100°C during evacuation of the canister to ensure that higher
molecular weight compounds are not retained on the walls of the canister.

[Note: For sampling more complex VOC mixtures the canisters should be heated to higher
temperatures during the cleaning procedure although a special high temperature valve would be
needed].

Once heated, the canisters are evacuated to <0.05 mm Hg (see Appendix B) and maintained
there for 1 hour. At the end of the heated/evacuated cycle, the canisters are pressurized with

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humid zero air and analyzed by a GC/MS system after a minimum of 12 hrs of "aging." Any
canister that has not tested clean (less than 0.2 ppbv each of targeted compounds) should not be
used. Once tested clean, the canisters are reevacuated to <0.05 mm Hg (see Appendix B) and
remain in the evacuated state until used. As noted in Section 8.4.1.7, reevacuation can occur just
prior to the next use.

8.4.2 Cleaning Sampling System Components.

8.4.2.1 Sample components are disassembled and cleaned before the sampler is assembled.
Nonmetallic parts are rinsed with HPLC grade deionized water and dried in a vacuum oven at
50°C. Typically, stainless steel parts and fittings are cleaned by placing them in a beaker of
methanol in an ultrasonic bath for 15 minutes. This procedure is repeated with hexane as the
solvent.

8.4.2.2 The parts are then rinsed with HPLC grade deionized water and dried in a vacuum oven
at 100°C for 12 to 24 hours.

8.4.2.3 Once the sampler is assembled, the entire system is purged with humid zero air for 24
hours.

8.4.3 Zero Air Certification.

[Note: In the following sections, "certification" is defined as evaluating the sampling system with
humid zero air and humid calibration gases that pass through all active components of the
sampling system. The system is "certified" if no significant additions or deletions (less than 0.2
ppbv each of target compounds) have occurred when challenged with the test gas stream.]

8.4.3.1 The cleanliness of the sampling system is determined by testing the sampler with humid
zero air without an evacuated gas sampling canister, as follows.

8.4.3.2 The calibration system and manifold are assembled, as illustrated in Figure 8. The
sampler (without an evacuated gas canister) is connected to the manifold and the zero air
cylinder is activated to generate a humid gas stream (2 L/min) to the calibration manifold [see
Figure 8(b)],

8.4.3.3 The humid zero gas stream passes through the calibration manifold, through the sampling
system (without an evacuated canister) to the water management system/VOC preconcentrator
of an analytical system.

[Note: The exit of the sampling system (without the canister) replaces the canister in Figure 11.]

After the sample volume (e.g., 500 mL) is preconcentrated on the trap, the trap is heated and the
VOCs are thermally desorbed and refocused on a cold trap. This trap is heated and the VOCs are
thermally desorbed onto the head of the capillary column. The VOCs are refocused prior to gas
chromatographic separation. Then, the oven temperature (programmed) increases and the VOCs
begin to elute and are detected by a GC/MS (see Section 10) system. The analytical system
should not detect greater than 0.2 ppbv of any targeted VOCs in order for the sampling system to
pass the humid zero air certification test. Chromatograms (using an FID) of a certified sampler
and contaminated sampler are illustrated in Figures 12(a) and 12(b), respectively. If the sampler
passes the humid zero air test, it is then tested with humid calibration gas standards containing
selected VOCs at concentration levels expected in field sampling (e.g., 0.5 to 2 ppbv) as outlined
in Section 8.4.4.

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8.4.4 Sampler System Certification with Humid Calibration Gas Standards from a Dynamic
Calibration System.

8.4.4.1 Assemble the dynamic calibration system and manifold as illustrated in Figure 8.

8.4.4.2 Verify that the calibration system is clean (less than 0.2 ppbv of any target compounds) by
sampling a humidified gas stream, without gas calibration standards, with a previously certified
clean canister (see Section 8.1).

8.4.4.3 The assembled dynamic calibration system is certified clean if less than 0.2 ppbv of any
targeted compounds is found.

8.4.4.4 For generating the humidified calibration standards, the calibration gas cylinder(s)
containing nominal concentrations of 10 ppmv in nitrogen of selected VOCs is attached to the
calibration system as illustrated in Figure 8. The gas cylinders are opened and the gas mixtures
are passed through 0 to 10 mL/min certified mass flow controllers to generate ppb levels of
calibration standards.

8.4.4.5 After the appropriate equilibrium period, attach the sampling system (containing a certified
evacuated canister) to the manifold, as illustrated in Figure 8(b).

8.4.4.6 Sample the dynamic calibration gas stream with the sampling system.

8.4.4.7 Concurrent with the sampling system operation, realtime monitoring of the calibration gas
stream is accomplished by the on-line GC/MS analytical system [Figure 8(a)] to provide reference
concentrations of generated VOCs.

8.4.4.8 At the end of the sampling period (normally the same time period used for experiments),
the sampling system canister is analyzed and compared to the reference GC/MS analytical
system to determine if the concentration of the targeted VOCs was increased or decreased by the
sampling system.

8.4.4.9 A recovery of between 90% and 110% is expected for all targeted VOCs.

8.4.5 Sampler System Certification without Compressed Gas Cylinder Standards.

8.4.5.1 Not all the gases on the Title III list are available/compatible with compressed gas
standards. In these cases sampler certification must be approached by different means.

8.4.5.2 Definitive guidance is not currently available in these cases; however, Section 9.2 lists
several ways to generate gas standards. In general, Compendium Method TO-14A compounds
(see Table 1) are available commercially as compressed gas standards.

9. GC/MS Analysis of Volatiles from Canisters

9.1 Introduction

9.1.1 The analysis of canister samples is accomplished with a GC/MS system. Fused silica capillary
columns are used to achieve high temporal resolution of target compounds. Linear quadrupole orion
trap mass spectrometers are employed for compound detection. The heart of the system is
composed of the sample inlet concentrating device that is needed to increase sample loading into a
detectable range. Two examples of concentrating systems are discussed. Other approaches are

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acceptable as long as they are compatible with achieving the system performance criteria given in
Section 11.

9.1.2 With the first technique, a whole air sample from the canister is passed through a multisorbent
packing (including single adsorbent packings) contained within a metal or glass tube maintained at or
above the surrounding air temperature. Depending on the water retention properties of the packing,
some or most of the water vapor passes completely through the trap during sampling. Additional
drying of the sample is accomplished after the sample concentration is completed by forward purging
the trap with clean, dry helium or another inert gas (air is not used). The sample is then thermally
desorbed from the packing and backflushed from the trap onto a gas chromatographic column. In
some systems a "refocusing" trap is placed between the primary trap and the gas chromatographic
column. The specific system design downstream of the primary trap depends on technical factors
such as the rate of thermal desorption and sampled volume, but the objective in most cases is to
enhance chromatographic resolution of the individual sample components before detection on a mass
spectrometer.

9.1.3 Sample drying strategies depend on the target list of compounds. For some target compound
lists, the multisorbent packing of the concentrator can be selected from hydrophobic adsorbents
which allow a high percentage of water vapor in the sample to pass through the concentrator during
sampling and without significant loss of the target compounds. However, if very volatile organic
compounds are on the target list, the adsorbents required for their retention may also strongly retain
water vapor and a more lengthy dry purge is necessary prior to analysis.

9.1.4 With the second technique, a whole air sample is passed through a concentrator where the
VOCs are condensed on a reduced temperature surface (cold trap). Subsequently, the condensed
gases are thermally desorbed and backflushed from the trap with an inert gas onto a gas
chromatographic column. This concentration technique is similar to that discussed in Compendium
Method TO-14, although a membrane dryer is not used. The sample size is reduced in volume to limit
the amount of water vapor that is also collected (100 mL or less may be necessary). The attendant
reduction in sensitivity is offset by enhancing the sensitivity of detection, for example by using an ion
trap detector.

9.2 Preparation of Standards
9.2.1 Introduction.

9.2.1.1 When available, standard mixtures of target gases in high pressure cylinders must be
certified traceable to a NIST Standard Reference Material (SRM) or to a NIST/EPA approved
Certified Reference Material (CRM). Manufacturer's certificates of analysis must be retained to
track the expiration date.

9.2.1.2 The neat standards that are used for making trace gas standards must be of high purity;
generally a purity of 98 percent or better is commercially available.

9.2.1.3 Cylinder(s) containing approximately 10 ppmv of each of the target compounds are
typically used as primary stock standards. The components may be purchased in one cylinder or
in separate cylinders depending on compatibility of the compounds and the pressure of the
mixture in the cylinder. Refer to manufacturer's specifications for guidance on purchasing and
mixing VOCs in gas cylinders.

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9.2.2 Preparing Working Standards.

9.2.2.1 Instrument Performance Check Standard. Prepare a standard solution of BFB in
humidified zero air at a concentration which will allow collection of 50 ng of BFB or less under the
optimized concentration parameters.

9.2.2.2 Calibration Standards. Prepare five working calibration standards in humidified zero air
at a concentration which will allow collection at the 2, 5, 10, 20, and 50 ppbv level for each
component under the optimized concentration parameters.

9.2.2.3 Internal Standard Spiking Mixture. Prepare an internal spiking mixture containing
bromo- chloromethane, chlorobenzene-d5, and 1,4-difluorobenzene at 10 ppmv each in
humidified zero air to be added to the sample or calibration standard. 500 |jl_ of this mixture
spiked into 500 mL of sample will result in a concentration of 10 ppbv. The internal standard is
introduced into the trap during the collection time for all calibration, blank, and sample analyses
using the apparatus shown in Figure 13 or by equivalent means. The volume of internal standard
spiking mixture added for each analysis must be the same from run to run.

9.2.3 Standard Preparation by Dynamic Dilution Technique.

9.2.3.1 Standards may be prepared by dynamic dilution of the gaseous contents of a cylinder(s)
containing the gas calibration stock standards with humidified zero air using mass flow controllers
and a calibration manifold. The working standard may be delivered from the manifold to a clean,
evacuated canister using a pump and mass flow controller.

9.2.3.2 Alternatively, the analytical system may be calibrated by sampling directly from the
manifold if the flow rates are optimized to provide the desired amount of calibration standards.
However, the use of the canister as a reservoir prior to introduction into the concentration system
resembles the procedure normally used to collect samples and is preferred. Flow rates of the
dilution air and cylinder standards (all expressed in the same units) are measured using a bubble
meter or calibrated electronic flow measuring device, and the concentrations of target compounds
in the manifold are then calculated using the dilution ratio and the original concentration of each
compound.

(Original Conc.)(Std. Gas Flowrate)

Manifold Cone. = .t. ——,^x-, ^—— —

(Air Flowrate) + (Std. Gas Flowrate)

9.2.3.3 Consider the example of 1 mL/min flow of 10 ppmv standard diluted with 1,000 mL/min of
humid air provides a nominal 10 ppbv mixture, as calculated below:

(10 ppm)(1 mL/min)(1000 ppb/1 ppm)

Manifold Cone. = —————: — = 10 ppb

1000 mL/min + 1 mL/min

9.2.4 Standard Preparation by Static Dilution Bottle Technique

[Note: Standards may be prepared in canisters by spiking the canister with a mixture of components
prepared in a static dilution bottle (12). This technique is used specifically for liquid standards.]

9.2.4.1 The volume of a clean 2-liter round-bottom flask, modified with a threaded glass neck to
accept a Mininert septum cap, is determined by weighing the amount of water required to
completely fill up the flask. Assuming a density for the water of 1 g/mL, the weight of the water in
grams is taken as the volume of the flask in milliliters.

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9.2.4.2 The flask is flushed with helium by attaching a tubing into the glass neck to deliver the
helium. After a few minutes, the tubing is removed and the glass neck is immediately closed with
a Mininert septum cap.

9.2.4.3 The flask is placed in a 60°C oven and allowed to equilibrate at that temperature for about
15 minutes. Predetermined aliquots of liquid standards are injected into the flask making sure to
keep the flask temperature constant at 60°C.

9.2.4.4 The contents are allowed to equilibrate in the oven for at least 30 minutes. To avoid
condensation, syringes must be preheated in the oven at the same temperature prior to
withdrawal of aliquots to avoid condensation.

9.2.4.5 Sample aliquots may then be taken for introduction into the analytical system or for further
dilution. An aliquot or aliquots totaling greater than 1 percent of the flask volume should be
avoided.

9.2.4.6 Standards prepared by this method are stable for one week. The septum must be
replaced with each freshly prepared standard.

9.2.4.7 The concentration of each component in the flask is calculated using the following
equation:

(Va)(d)

Concentration, mg/L = ———

where:

Va = Volume of liquid neat standard injected into the flask, |jl_.
d = Density of the liquid neat standard, mg/jjL.

Vf = Volume of the flask, L.

9.2.4.8 To obtain concentrations in ppbv, the equation given in Section 9.2.5.7 can be used.

[Note: In the preparation of standards by this technique, the analyst should make sure that the
volume of neat standard injected into the flask does not result in an overpressure due to the
higher partial pressure produced by the standard compared to the vapor pressure in the flask.
Precautions should also be taken to avoid a significant decrease in pressure inside the flask after
withdrawal of aliquot(s).]

9.2.5 Standard Preparation Procedure in High Pressure Cylinders

[Note: Standards may be prepared in high pressure cylinders (13). A modified summary of the
procedure is provided below.]

9.2.5.1 The standard compounds are obtained as gases or neat liquids (greater than 98 percent
purity).

9.2.5.2 An aluminum cylinder is flushed with high-purity nitrogen gas and then evacuated to better
than 25 in. Hg.

9.2.5.3 Predetermined amounts of each neat standard compound are measured using a microliter
or gastight syringe and injected into the cylinder. The cylinder is equipped with a heated injection
port and nitrogen flow to facilitate sample transfer.

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9.2.5.4	The cylinder is pressurized to 1000 psig with zero nitrogen.

[Note: User should read all SOPs associated with generating standards in high pressure
cylinders. Follow all safety requirements to minimize danger from high pressure cylinders.]

9.2.5.5	The contents of the cylinder are allowed to equilibrate (~24 hrs) prior to withdrawal of
aliquots into the GC system.

9.2.5.6	If the neat standard is a gas, the cylinder concentration is determined using the following
equation:

VolumeofanriaiTj	q

Concentration, ppbv= —	x10

VolumedNution gas

[Note: Both values must be expressed in the same units.]

9.2.5.7	If the neat standard is a liquid, the gaseous concentration can be determined using the
following equations:

and

(mL)(d)

" MW

where:

V = Gaseous volume of injected compound at EPA standard temperature (25°C) and
pressure (760 mm Hg), L.

n = Moles.

R = Gas constant, 0.08206 L-atm/mole °K.

T = 298°K (standard temperature).

P = 1 standard pressure, 760 mm Hg (1 atm).
mL = Volume of liquid injected, mL.
d = Density of the neat standard, g/mL.

MW = Molecular weight of the neat standard expressed, g/g-mole.

The gaseous volume of the injected compound is divided by the cylinder volume at STP and then
multiplied by 109 to obtain the component concentration in ppb units.

9.2.6 Standard Preparation by Water Methods.

[Note: Standards may be prepared by a water purge and trap method (14) and summarized as
follows],

9.2.6.1	A previously cleaned and evacuated canister is pressurized to 760 mm Hg absolute (1
atm) with zero grade air.

9.2.6.2	The air gauge is removed from the canister and the sparging vessel is connected to the
canister with the short length of 1/16 in. stainless steel tubing.

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[Note: Extra effort should be made to minimize possible areas of dead volume to maximize
transfer of analytes from the water to the canister.]

9.2.6.3 A measured amount of the stock standard solution and the internal standard solution is
spiked into 5 mL of water.

9.2.6.4 This water is transferred into the sparge vessel and purged with nitrogen for 10 mins at
100 mL/min. The sparging vessel is maintained at 40°C.

9.2.6.5 At the end of 10 mins, the sparge vessel is removed and the air gauge is re-installed, to
further pressurize the canister with pure nitrogen to 1500 mm Hg absolute pressure
(approximately 29 psia).

9.2.6.6 The canister is allowed to equilibrate overnight before use.

9.2.6.7 A schematic of this approach is shown in Figure 14.

9.2.7 Preparation of Standards by Permeation Tubes.

9.2.7.1 Permeation tubes can be used to provide standard concentration of a trace gas or gases.
The permeation of the gas can occur from inside a permeation tube containing the trace species
of interest to an air stream outside. Permeation can also occur from outside a permeable
membrane tube to an air stream passing through the tube (e.g., a tube of permeable material
immersed in a liquid).

9.2.7.2 The permeation system is usually held at a constant temperature to generate a constant
concentration of trace gas. Commercial suppliers provide systems for generation and dilution of
over 250 compounds. Some commercial suppliers of permeation tube equipment are listed in
Appendix D.

9.2.8 Storage of Standards.

9.2.8.1 Working standards prepared in canisters may be stored for thirty days in an atmosphere
free of potential contaminants.

9.2.8.2 It is imperative that a storage logbook be kept to document storage time.

10. GC/MS Operating Conditions

10.1 Preconcentrator

The following are typical cryogenic and adsorbent preconcentrator analytical conditions which, however,
depend on the specific combination of solid sorbent and must be selected carefully by the operator. The
reader is referred to Tables 1 and 2 of Compendium Method TO-17 for guidance on selection of sorbents
An example of a system using a solid adsorbent preconcentrator with a cryofocusing trap is discussed in
the literature (15). Oven temperature programming starts above ambient.

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10.1.1 Sample Collection Conditions

Cryogenic Trap

Adsorbent Trap

Set point

-150°C

Set point

27°C

Sample volume

- up to 100 ml.

Sample volume

- up to 1,000 ml.

Carrier gas purge flow

- none

Carrier gas purge flow

- selectable

[Note: The analyst should optimize the flow rate, duration of sampling, and absolute sample volume
to be used. Other preconcentration systems may be used provided performance standards (see
Section 11) are realized.]

10.1.2 Desorption Conditions

Cryogenic Trap

Adsorbent Trap

Desorb Temperature

120°C

Desorb Temperature

Variable

Desorb Flow Rate

~ 3 mL/min He

Desorb Flow Rate

~ 3 mL/min He

Desorb Time

<60 sec

Desorb Time

<60 sec

The adsorbent trap conditions depend on the specific solid adsorbents chosen (see manufacturers'
specifications).

10.1.3 Trap Reconditioning Conditions.

Cryogenic Trap

Adsorbent Trap

Initial bakeout
Variable (24hrs)

120°C (24 hrs)

Initial bakeout

Variable

After each run

120°C (5 min)

After each run

Variable (5 min)

10.2 GC/MS System

10.2.1	Optimize GC conditions for compound separation and sensitivity. Baseline separation of
benzene and carbon tetrachloride on a 100% methyl polysiloxane stationary phase is an indication of
acceptable chromatographic performance.

10.2.2	The following are the recommended gas chromatographic analytical conditions when using a
50-meter by 0.3-mm I.D., 1 jjm film thickness fused silica column with refocusing on the column.

Item

Carrier Gas:

Flow Rate:

Temperature Program:

Condition

Helium

Generally 1-3 mL/min as
recommended by manufacturer

Initial Temperature:

Initial Hold Time:

Ramp Rate:

Final Temperature:

Final Hold Time:

-50°C
2 min
8° C/min
200°C

Until all target compounds elute

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10.2.3 The following are the recommended mass spectrometer conditions:

Item

Electron Energy:
Mass Range:

Condition

70 Volts (nominal)

35-300 amu [the choice of 35 amu excludes the detection of some target
compounds such as methanol and formaldehyde, and the quantitation of others
such as ethylene oxide, ethyl carbamate, etc. (see Table 2). Lowering the mass range
and using special programming features available on modern gas chromatographs
will be necessary in these cases, but are not considered here.

To give at least 10 scans per peak, not to exceed 1 second per scan.

Scan Time:

A schematic for a typical GC/MS analytical system is illustrated in Figure 15.

10.3 Analytical Sequence

10.3.1 Introduction. The recommended GC/MS analytical sequence for samples during each 24-
hour time period is as follows:

• Perform instrument performance check using bromofluorobenzene (BFB).

• Initiate multi-point calibration or daily calibration checks.

• Perform a laboratory method blank.

• Complete this sequence for analysis of < 20 field samples.

10.4 Instrument Performance Check

10.4.1 Summary. It is necessary to establish that a given GC/MS meets tuning and standard mass
spectral abundance criteria prior to initiating any data collection. The GC/MS system is set up
according to the manufacturer's specifications, and the mass calibration and resolution of the GC/MS
system are then verified by the analysis of the instrument performance check standard,
bromofluorobenzene (BFB).

10.4.2 Frequency. Prior to the analyses of any samples, blanks, or calibration standards, the
Laboratory must establish that the GC/MS system meets the mass spectral ion abundance criteria for
the instrument performance check standard containing BFB. The instrument performance check
solution must be analyzed initially and once per 24-hour time period of operation.

The 24-hour time period for GC/MS instrument performance check and standards calibration (initial
calibration or daily calibration check criteria) begins at the injection of the BFB which the laboratory
records as documentation of a compliance tune.

10.4.3 Procedure. The analysis of the instrument performance check standard is performed by
trapping 50 ng of BFB under the optimized preconcentration parameters. The BFB is introduced from
a cylinder into the GC/MS via a sample loop valve injection system similar to that shown in Figure 13.

The mass spectrum of BFB must be acquired in the following manner. Three scans (the peak apex
scan and the scans immediately preceding and following the apex) are acquired and averaged.
Background subtraction is conducted using a single scan prior to the elution of BFB.

10.4.4 Technical Acceptance Criteria. Prior to the analysis of any samples, blanks, or calibration
standards, the analyst must establish that the GC/MS system meets the mass spectral ion
abundance criteria for the instrument performance check standard as specified in Table 3.

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10.4.5 Corrective Action. If the BFB acceptance criteria are not met, the MS must be retuned. It may
be necessary to clean the ion source, or quadruples, or take other necessary actions to achieve the
acceptance criteria.

10.4.6 Documentation. Results of the BFB tuning are to be recorded and maintained as part of the
instrumentation log.

10.5 Initial Calibration

10.5.1 Summary. Prior to the analysis of samples and blanks but after the instrument performance
check standard criteria have been met, each GC/MS system must be calibrated at five concentrations
that span the monitoring range of interest in an initial calibration sequence to determine instrument
sensitivity and the linearity of GC/MS response for the target compounds. For example, the range of
interest may be 2 to 20 ppbv, in which case the five concentrations would be 1, 2, 5, 10 and 25 ppbv.

One of the calibration points from the initial calibration curve must be at the same concentration as
the daily calibration standard (e.g., 10 ppbv).

10.5.2 Frequency. Each GC/MS system must be recalibrated following corrective action (e.g., ion
source cleaning or repair, column replacement, etc.) which may change or affect the initial calibration
criteria or if the daily calibration acceptance criteria have not been met.

If time remains in the 24-hour time period after meeting the acceptance criteria for the initial
calibration, samples may be analyzed.

If time does not remain in the 24-hour period after meeting the acceptance criteria for the initial
calibration, a new analytical sequence shall commence with the analysis of the instrument
performance check standard followed by analysis of a daily calibration standard.

10.5.3 Procedure. Verify that the GC/MS system meets the instrument performance criteria in
Section 10.4.

The GC must be operated using temperature and flow rate parameters equivalent to those in Section
10.2.2. Calibrate the preconcentration-GC/MS system by drawing the standard into the system. Use
one of the standards preparation techniques described under Section 9.2 or equivalent.

A minimum of five concentration levels are needed to determine the instrument sensitivity and
linearity. One of the calibration levels should be near the detection level for the compounds of
interest. The calibration range should be chosen so that linear results are obtained as defined in
Sections 10.5.1 and 10.5.5.

Quantitation ions for the target compounds are shown in Table 2. The primary ion should be used
unless interferences are present, in which case a secondary ion is used.

10.5.4 Calculations.

[Note: In the following calculations, an internal standard approach is used to calculate response
factors. The area response used is that of the primary quantitation ion unless otherwise stated.]

10.5.4.1 Relative Response Factor (wherRRF). Calculate the relative response factors for each
target compound relative to the appropriate internal standard (i.e., standard with the nearest
retention time) using the following equation:

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AxCjS

AiSCx

where:

RRF = Relative response factor.

Ax = Area of the primary ion for the compound to be measured, counts.

AjS = Area of the primary ion for the internal standard, counts.

CjS = Concentration of internal standard spiking mixture, ppbv.

Cx = Concentration of the compound in the calibration standard, ppbv.

[Note: The equation above is valid under the condition that the volume of internal standard
spiking mixture added in all field and QC analyses is the same from run to run, and that the
volume of field and QC sample introduced into the trap is the same for each analysis. Cis and
Cx must be in the same units.]

10.5.4.2 Mean Relative Response Factor. Calculate the mean RRF for each compound by
averaging the values obtained at the five concentrations using the following equation:

n

v x.

RRF= > —
Z_i n

i=1

where:

RRF= Mean relative response factor.

xj = RRF of the compound at concentration i.

n = Number of concentration values, in this case 5.

10.5.4.3 Percent Relative Standard Deviation (%RSD). Using the RRFs from the initial
calibration, calculate the %RSD for all target compounds using the following equations

SDrrf
%RSD = —— x 100
RRF

and

N

Z(RRF| - RRF)

isTl

i=1

sdrrf-

N

where:

SDrrf = Standard deviation of initial response factors (per compound).
RRFi= Relative response factor at a concentration level i.

RRF = Mean of initial relative response factors (per compound).

10.5.4.4 Relative Retention Times (RRT). Calculate the RRTs for each target compound over
the initial calibration range using the following equation:

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RTr

RRT=-

RTis
where:

RTC = Retention time of the target compound, seconds
RTis = Retention time of the internal standard, seconds.

10.5.4.5 Mean of the Relative Retention Times (RRT). Calculate the mean of the relative

retention times (RRT) for each analyte target compound over the initial calibration range using the
following equation:

ZRRT
	

n

i=1

where:

RRT = Mean relative retention time for the target compound for each initial
calibration standard.

RRT = Relative retention time for the target compound at each calibration level.

10.5.4.6	Tabulate Primary Ion Area Response (Y) for Internal Standard. Tabulate the area
response (Y) of the primary ions (see Table 2) and the corresponding concentration for each
compound and internal standard.

10.5.4.7	Mean Area Response (?) for Internal Standard. Calculate the mean area response (?)
for each internal standard compound over the initial calibration range using the following
equation:

n

?=^Yi

Z_i n

i=1

where:

?= Mean area response.

Y = Area response for the primary quantitation ion for the internal standard for each
initial calibration standard.

10.5.4.8 Mean Retention Times (RT). Calculate the mean of the retention times (RT) for each
internal standard over the initial calibration range using the following equation:

n

	 V'RTi

RT= > —-
Z_i n

i=1

where:

RT = Mean retention time, seconds

RT = Retention time for the internal standard for each initial calibration standard,
seconds.

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10.5.5 Technical Acceptance Criteria for the Initial Calibration.

10.5.5.1 The calculated %RSD for the RRF for each compound in the calibration table must be
less than 30% with at most two exceptions up to a limit of 40%.

[Note: This exception may not be acceptable for all projects. Many projects may have a specific
target list of compounds which would require the lower limit for all compounds.]

10.5.5.2 The RRT for each target compound at each calibration level must be within 0.06 RRT
units of the mean RRT for the compound.

10.5.5.3 The area response Y of at each calibration level must be within 40% of the mean area
response Y over the initial calibration range for each internal standard.

10.5.5.4 The retention time shift for each of the internal standards at each calibration level must
be within 20 s of the mean retention time over the initial calibration range for each internal
standard.

10.5.6 Corrective Action.

10.5.6.1 Criteria. If the initial calibration technical acceptance criteria are not met, inspect the
system for problems. It may be necessary to clean the ion source, change the column, or take
other corrective actions to meet the initial calibration technical acceptance criteria.

10.5.6.2 Schedule. Initial calibration acceptance criteria must be met before any field samples,
performance evaluation (PE) samples, or blanks are analyzed.

10.6 Daily Calibration

10.6.1 Summary. Prior to the analysis of samples and blanks but after tuning criteria have been met,
the initial calibration of each GC/MS system must be routinely checked by analyzing a daily
calibration standard to ensure that the instrument continues to remain under control. The daily
calibration standard, which is the nominal 10 ppbv level calibration standard, should contain all the
target compounds.

10.6.2 Frequency. A check of the calibration curve must be performed once every 24 hours on a
GC/MS system that has met the tuning criteria. The daily calibration sequence starts with the injection
of the BFB. If the BFB analysis meets the ion abundance criteria for BFB, then a daily calibration
standard may be analyzed.

10.6.3 Procedure. The mid-level calibration standard (10 ppbv) is analyzed in a GC/MS system that
has met the tuning and mass calibration criteria following the same procedure in Section 10.5.

10.6.4 Calculations. Perform the following calculations.

[Note: As indicated earlier, the area response of the primary quantitation ion is used unless otherwise
stated.]

10.6.4.1 Relative Response Factor (RRF). Calculate a relative response factor (RRF) for each
target compound using the equation in Section 10.5.4.1.

10.6.4.2 Percent Difference (%D). Calculate the percent difference in the RRF of the daily RRF
(24-hour) compared to the mean RRF in the most recent initial calibration. Calculate the %D for
each target compound using the following equation:

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%D =

RRFC - RRF|

x 100

RRF;

where:

RRFC = RRF of the compound in the continuing calibration standard.

RRFj = Mean RRF of the compound in the most recent initial calibration,

10.6.5 Technical Acceptance Criteria. The daily calibration standard must be analyzed at the
concentration level and frequency described in this Section 10.6 and on a GC/MS system meeting the
BFB instrument performance check criteria (see Section 10.4).

The %D for each target compound in a daily calibration sequence must be within ±30 percent in order
to proceed with the analysis of samples and blanks. A control chart showing %D values should be
maintained.

10.6.6 Corrective Action. If the daily calibration technical acceptance criteria are not met, inspect the
system for problems. It may be necessary to clean the ion source, change the column, or take other
corrective actions to meet the daily calibration technical acceptance criteria.

Daily calibration acceptance criteria must be met before any field samples, performance evaluation
(PE) samples, or blanks are analyzed. If the % D criteria are not met, it will be necessary to rerun the
daily calibration sample.

10.7 Blank Analyses

10.7.1 Summary. To monitor for possible laboratory contamination, laboratory method blanks are
analyzed at least once in a 24-hour analytical sequence. All steps in the analytical procedure are
performed on the blank using all reagents, standards, equipment, apparatus, glassware, and solvents
that would be used for a sample analysis.

A laboratory method blank (LMB) is an unused, certified canister that has not left the laboratory. The
blank canister is pressurized with humidified, ultra-pure zero air and carried through the same
analytical procedure as a field sample. The injected aliquot of the blank must contain the same
amount of internal standards that are added to each sample.

10.7.2 Frequency. The laboratory method blank must be analyzed after the calibration standard(s)
and before any samples are analyzed.

Whenever a high concentration sample is encountered (i.e., outside the calibration range), a blank
analysis should be performed immediately after the sample is completed to check for carryover
effects.

10.7.3 Procedure. Fill a cleaned and evacuated canister with humidified zero air (RH >20 percent, at
25°C). Pressurize the contents to 2 atm.

The blank sample should be analyzed using the same procedure outlined under Section 10.8.

10.7.4 Calculations. The blanks are analyzed similar to a field sample and the equations in Section
10.5.4 apply.

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10.7.5 Technical Acceptance Criteria. A blank canister should be analyzed daily.

The area response for each internal standard (IS) in the blank must be within ±40 percent of the
mean area response of the IS in the most recent valid calibration.

The retention time for each of the internal standards must be within ±0.33 minutes between the blank
and the most recent valid calibration.

The blank should not contain any target analyte at a concentration greater than its quantitation level
(three times the MDL as defined in Section 11.2) and should not contain additional compounds with
elution characteristics and mass spectral features that would interfere with identification and
measurement of a method analyte.

10.7.6 Corrective Action. If the blanks do not meet the technical acceptance criteria, the analyst
should consider the analytical system to be out of control. It is the responsibility of the analyst to
ensure that contaminants in solvents, reagents, glassware, and other sample storage and processing
hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms be
eliminated. If contamination is a problem, the source of the contamination must be investigated and
appropriate corrective measures need to be taken and documented before further sample analysis
proceeds.

If an analyte in the blank is found to be out of control (i.e., contaminated) and the analyte is also
found in associated samples, those sample results should be "flagged" as possibly contaminated.

10.8 Sample Analysis

10.8.1 Summary. An aliquot of the air sample from a canister (e.g., 500 mL) is preconcentrated and
analyzed by GC/MS under conditions stated in Sections 10.1 and 10.2. If using the multisorbent/dry
purge approach, adjust the dry purge volume to reduce water effects in the analytical system to
manageable levels.

[Note: The analyst should be aware that pressurized samples of high humidity samples will contain
condensed water. As a result, the humidity of the sample released from the canister during analysis
will vary in humidity, being lower at the higher canister pressures and increasing in humidity as the
canister pressures decreases. Storage integrity of water soluble compounds may also be affected.]

10.8.2 Frequency. If time remains in the 24-hour period in which an initial calibration is performed,
samples may be analyzed without analysis of a daily calibration standard.

If time does not remain in the 24-hour period since the injection of the instrument performance check
standard in which an initial calibration is performed, both the instrument performance check standard
and the daily calibration standard should be analyzed before sample analysis may begin.

10.8.3 Procedure for Instrumental Analysis. Perform the following procedure for analysis.

10.8.3.1 All canister samples should be at temperature equilibrium with the laboratory.

10.8.3.2 Check and adjust the mass flow controllers to provide correct flow rates for the system.

10.8.3.3 Connect the sample canister to the inlet of the GC/MS analytical system, as shown in
Figure 15 [Figure 16 shows an alternate two stage concentrator using multisorbent traps followed
by a trap cooled by a closed cycle cooler (15)]. The desired sample flow is established through
the six-port chromatographic valve and the preconcentrator to the downstream flow controller.
The absolute volume of sample being pulled through the trap must be consistent from run to run.

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10.8.3.4 Heat/cool the GC oven and cryogenic or adsorbent trap to their set points. Assuming a
six-port value is being used, as soon as the trap reaches its lower set point, the six-port
chromatographic valve is cycled to the trap position to begin sample collection. Utilize the sample
collection time which has been optimized by the analyst.

10.8.3.5 Use the arrangement shown in Figure 13, (i.e., a gastight syringe or some alternate
method) introduce an internal standard during the sample collection period. Add sufficient internal
standard equivalent to 10 ppbv in the sample. For example, a 0.5 mL volume of a mixture of
internal standard compounds, each at 10 ppmv concentration, added to a sample volume of 500
mL, will result in 10 ppbv of each internal standard in the sample.

10.8.3.6 After the sample and internal standards are preconcentrated on the trap, the GC
sampling valve is cycled to the inject position and the trap is swept with helium and heated.
Assuming a focusing trap is being used, the trapped analytes are thermally desorbed onto a
focusing trap and then onto the head of the capillary column and are separated on the column
using the GC oven temperature program. The canister valve is closed and the canister is
disconnected from the mass flow controller and capped. The trap is maintained at elevated
temperature until the beginning of the next analysis.

10.8.3.7 Upon sample injection onto the column, the GC/MS system is operated so that the MS
scans the atomic mass range from 35 to 300 amu. At least ten scans per eluting chromatographic
peak should be acquired. Scanning also allows identification of unknown compounds in the
sample through searching of library spectra.

10.8.3.8 Each analytical run must be checked for saturation. The level at which an individual
compound will saturate the detection system is a function of the overall system sensitivity and the
mass spectral characteristics of that compound.

10.8.3.9 Secondary ion quantitation is allowed only when there are sample matrix interferences
with the primary ion. If secondary ion quantitation is performed, document the reasons in the
laboratory record book.

10.8.4 Calculations. The equation below is used for calculating concentrations.

^ _ AxCisDF

ARRF

where:

Cx = Compound concentration, ppbv.

Ax = Area of the characteristic ion for the compound to be measured, counts.

AjS = Area of the characteristic ion for the specific internal standard, counts.
CjS = Concentration of the internal standard spiking mixture, ppbv
RRF =Mean relative response factor from the initial calibration.

DF = Dilution factor calculated as described in section 2. If no dilution is performed, DF = 1.

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[Note: The equation above is valid under the condition that the volume (500 |jl_) of internal
standard spiking mixture added in all field and QC analyses is the same from run to run, and that the
volume (500 mL) of field and QC sample introduced into the trap is the same for each analysis.]

10.8.5 Technical Acceptance Criteria.

[Note: If the most recent valid calibration is an initial calibration, internal standard area responses and
RTs in the sample are evaluated against the corresponding internal standard area responses and
RTs in the mid level standard (10 ppbv) of the initial calibration.]

10.8.5.1 The field sample must be analyzed on a GC/MS system meeting the BFB tuning, initial
calibration, and continuing calibration technical acceptance criteria at the frequency described in
Sections 10.4, 10.5 and 10.6.

10.8.5.2 The field samples must be analyzed along with a laboratory method blank that met the
blank technical acceptance criteria.

10.8.5.3 All of the target analyte peaks should be within the initial calibration range.

10.8.5.4 The retention time for each internal standard must be within ±0.33 minutes of the
retention time of the internal standard in the most recent valid calibration.

10.8.6 Corrective Action. If the on-column concentration of any compound in any sample exceeds
the initial calibration range, an aliquot of the original sample must be diluted and reanalyzed.

Guidance in performing dilutions and exceptions to this requirement are given below.

• Use the results of the original analysis to determine the approximate dilution factor required to
get the largest analyte peak within the initial calibration range.

• The dilution factor chosen should keep the response of the largest analyte peak for a target
compound in the upper half of the initial calibration range of the instrument.

[Note: Analysis involving dilution should be reported with a dilution factor and nature of the dilution
gas.]

10.8.6.1 Internal standard responses and retention times must be evaluated during or
immediately after data acquisition. If the retention time for any internal standard changes by more
than 20 sec from the latest daily (24-hour) calibration standard (or mean retention time over the
initial calibration range), the GC/MS system must be inspected for malfunctions, and corrections
made as required.

10.8.6.2 If the area response for any internal standard changes by more than ±40 percent
between the sample and the most recent valid calibration, the GC/MS system must be inspected
for malfunction and corrections made as appropriate. When corrections are made, reanalysis of
samples analyzed while the system was malfunctioning is necessary.

10.8.6.3 If, after reanalysis, the area responses or the RTs for all internal standards are inside the
control limits, then the problem with the first analysis is considered to have been within the control
of the Laboratory. Therefore, submit only data from the analysis with SICPs within the limits. This
is considered the initial analysis and should be reported as such on all data deliverables.

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11. Requirements for Demonstrating Method Acceptability for VOC
Analysis from Canisters

11.1	Introduction

11.1.1	There are three performance criteria which must be met for a system to qualify under
Compendium Method TO-15. These criteria are: the method detection limit of <0.5 ppbv, replicate
precision within 25 percent, and audit accuracy within 30 percent for concentrations normally
expected in contaminated ambient air (0.5 to 25 ppbv).

11.1.2	Either SIM or SCAN modes of operation can be used to achieve these criteria, and the choice
of mode will depend on the number of target compounds, the decision of whether or not to determine
tentatively identified compounds along with other VOCs on the target list, as well as on the analytical
system characteristics.

11.1.3	Specific criteria for each Title III compound on the target compound list must be met by the
analytical system. These criteria were established by examining summary data from EPA's Toxics Air
Monitoring System Network and the Urban Air Toxics Monitoring Program network. Details for the
determination of each of the criteria follow.

11.2	Method Detection Limit

11.2.1	The procedure chosen to define the method detection limit is that given in the Code of Federal
Regulations (40 CFR 136 Appendix B).

11.2.2	The method detection limit is defined for each system by making seven replicate
measurements of the compound of interest at a concentration near (within a factor of five) the
expected detection limit, computing the standard deviation for the seven replicate concentrations, and
multiplying this value by 3.14 (i.e., the Student's t value for 99 percent confidence for seven values).
Employing this approach, the detection limits given in Table 4 were obtained for some of the VOCs of
interest.

11.3	Replicate Precision

11.3.1	The measure of replicate precision used for this program is the absolute value of the difference
between replicate measurements of the sample divided by the average value and expressed as a
percentage as follows:

|XrX2|

percent difference = —=— x 100
x

where:

x., = First measurement value.
x2 = Second measurement value,
x =Average of the two values

11.3.2	There are several factors which may affect the precision of the measurement. The nature of
the compound of interest itself such as molecular weight, water solubility, polarizability, etc., each
have some effect on the precision, for a given sampling and analytical system. For example, styrene,
which is classified as a polar VOC, generally shows slightly poorer precision than the bulk of nonpolar

36

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United States
Environmental Protection
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December 2015

VOCs

1	VOCs. A primary influence on precision is the concentration level of the compound of interest in the

2	sample, i.e., the precision degrades as the concentration approaches the detection limit. A

3	conservative measure was obtained from replicate analysis of "real world" canister samples from the

4	TAMS and UATMP networks. These data are summarized in Table 5 and suggest that a replicate

5	precision value of 25 percent can be achieved for each of the target compounds.

6	11.4 Audit Accuracy

7

8

9

10

11.4.1 A measure of analytical accuracy is the degree of agreement with audit standards. Audit
accuracy is defined as the difference between the nominal concentration of the audit compound and
the measured value divided by the audit value and expressed as a percentage, as illustrated in the
following equation:

11

12

13

11.4.2 Audit accuracy results for TAMS and UATMP analyses are summarized in Table 6 and were
used to form the basis for a selection of 30 percent as the performance criterion for audit accuracy.

14

16	1. Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method

17	TO-14A, Second Edition, U. S. Environmental Protection Agency, Research Triangle Park, NC, EPA

18	600/625/R-96/01 Ob, January 1997.

19	2. Winberry, W. T., Jr., et al., Statement-of-Work (SOW) for the Analysis of Air Toxics From Superfund

20	Sites, U. S. Environmental Protection Agency, Office of Solid Waste, Contract Laboratory Program,

21	Washington, D.C., Draft Report, June 1990.

22	3. Coutant, R.W., Theoretical Evaluation of Stability of Volatile Organic Chemicals and Polar

23	Volatile Organic Chemicals in Canisters, U. S. Environmental Protection Agency, EPA Contract No.

24	68-DO-0007, Work Assignment No. 45, Subtask 2, Battelle, Columbus, OH, June 1993.

25	4. Kelly, T.J., Mukund, R., Gordon, S.M., and Hays, M.J., Ambient Measurement Methods and

26	Properties of the 189 Title III Hazardous Air Pollutants, U. S. Environmental Protection Agency, EPA

27	Contract No. 68-DO-0007, Work Assignment 44, Battelle, Columbus, OH, March 1994.

28	5. Kelly T. J. and Holdren, M.W., "Applicability of Canisters for Sample Storage in the Determination

29	of Hazardous Air Pollutants," Atmos. Environ., Vol. 29, 2595-2608, May 1995.

30	6. Kelly, T.J., Callahan, P.J., Pleil, J.K., and Evans, G.E., "Method Development and Field

31	Measurements for Polar Volatile Organic Compounds in Ambient Air," Environ. Sci. Techno!., Vol. 27,

32	1146-1153, 1993.

33	7. McClenny, W.A., Oliver, K.D. and Daughtrey, E.H.., Jr. "Dry Purging of Solid Adsorbent Traps to

34	Remove Water Vapor Before Thermal Desorption of Trace Organic Gases," J. Air and Waste Manag.

35	Assoc., Vol. 45, 792-800, June 1995.

36	8. Whitaker, D.A., Fortmann, R.C. and Lindstrom, A.B. "Development and Testing of a Whole Air Sampler

37	for Measurement of Personal Exposures to Volatile Organic Compounds," Journal of Exposure Analysis

38	and Environmental Epidemiology, Vol. 5, No. 1, 89-100, January 1995.

37

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Environmental Protection	DOCGI1ll)9r 2015	VOvS

1	9. Pleil, J.D. and Lindstrom, A.B., "Collection of a Single Alveolar Exhaled Breath for Volatile

2	Organic Compound Analysis," American Journal of Industrial Medicine, Vol. 28, 109-121, 1995.

3	10. Pleil, J.D. and McClenny, W.A., "Spatially Resolved Monitoring for Volatile Organic Compounds

4	Using Remote Sector Sampling," Atmos. Environ., Vol. 27A, No. 5, 739-747, August 1993.

5	11. Holdren, M.W., et al., Unpublished Final Report, EPA Contract 68-DO-0007, Battelle, Columbus,

6	OH. Available from J.D. Pleil, MD-44, U. S. Environmental Protection Agency, Research Triangle Park,

7	NC, 27711, 919-541-4680.

8	12. Morris, C.M., Burkley, R.E. and Bumgarner, J.E., "Preparation of Multicomponent Volatile

9	Organic Standards Using Dilution Bottles," Anal. Letts., Vol. 16 (A20), 1585-1593, 1983.

10	13. Pollack, A.J., Holdren, M.W., "Multi-Adsorbent Preconcentration and Gas Chromatographic Analysis

11	of Air Toxics With an Automated Collection/Analytical System," in the Proceedings of the 1990

12	EPA/A&WMA International Symposium of Measurement of Toxic and Related Air Pollutants, U. S.

13	Environmental Protection Agency, Research Triangle Park, NC, EPA/600/9-90-026, May 1990.

14	14. Stephenson, J.H.M., Allen, F., Slagle, T., "Analysis of Volatile Organics in Air via Water Methods"

15	in Proceedings of the 1990 EPA/A&WMA International Symposium on Measurement of Toxic and

16	Related Air Pollutants, U. S. Environmental Protection Agency, Research Triangle Park, NC, EPA 600/9-90-

17	026, May 1990.

18	15. Oliver, K. D., Adams, J. R., Daughtrey, E. H., Jr., McClenny, W. A., Young, M. J., and Parade, M.

19	A., "Techniques for Monitoring Toxices VOCs in Air: Sorbent Preconcentration Closed-Cycle Cooler

20	Cryofocusing, and GC/MS Analysis," Environ. Sci. Techno!., Vol. 30, 1938-1945, 1996.

21

22

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Environrr
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Environmental Promotion	December 2015	VOCUl

Appendix A: Listing of Some Commercial Water Management Systems
Used with AutoGC Systems

Tekmar Dohrman Company
7143 East Kemper Road
Post Office Box 429576
Cincinnati, Ohio 45242-9576
(513) 247-7000
(513) 247-7050 (Fax)
(800) 543-4461
[Moisture control module]

Entech Laboratory Automation
950 Enchanted Way No. 101
Simi Valley, California 9306
(805) 527-5939
(805) 527-5687 (Fax)
[Microscale Purge and Trap]

Dynatherm Analytical Instruments
Post Office Box 159
Kelton, Pennsylvania 19346
(215) 869-8702
(215) 869-3885 (Fax)

[Thermal Desorption System]

XonTech Inc.

6862 Hayenhurst Avenue

Van Nuys, CA 91406

(818) 787-7380

(818) 787-4275 (Fax)

[Multi-adsorbent trap/dry purge]

Graseby

500 Technology Ct.

Smyrna, Georgia 30082
(770) 319-9999
(770) 319-0336(Fax)
(800) 241-6898
[Controlled Desorption Trap]

Varian Chromatography System

2700 Mitchell Drive

Walnut Creek, California 94898

(510) 945-2196

(510) 945-2335 (Fax)

[Variable Temperature Adsorption Trap]

39

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Appendix B: Comment en Canister Cleaning Procedures

The canister cleaning procedures given in Section 8.4 require that canister pressure be reduced to
<0.05mm Hg before the cleaning process is complete. Depending on the vacuum system design
(diameter of connecting tubing, valve restrictions, etc.) and the placement of the vacuum gauge, the
achievement of this value may take several hours. In any case, the pressure gauge should be placed
near the canisters to determine pressure. The objective of requiring a low pressure evacuation during
canister cleaning is to reduce contaminants. If canisters can be routinely certified (<0.2 ppbv for target
compounds) while using a higher vacuum, then this criteria can be relaxed. However, the ultimate
vacuum achieved during cleaning should always be <0.2mm Hg.

Canister cleaning as described in Section 8.4 and illustrated in Figure 10 requires components with
special features. The vacuum gauge shown in Figure 10 must be capable of measuring 0.05 mm Hg with
less than a 20% error. The vacuum pump used for evacuating the canister must be noncontaminating
while being capable of achieving the 0.05 mm Hg vacuum as monitored near the canisters.
Thermoelectric vacuum gauges and turbomolecular drag pumps are typically being used for these two
components.

An alternate to achieving the canister certification requirement of <0.2 ppbv for all target compounds
is the criteria used in Compendium Method TO-12 that the total carbon count be <10ppbC. This
check is less expensive and typically more exacting than the current certification requirement and can be
used if proven to be equivalent to the original requirement. This equivalency must be established by
comparing the total nonmethane organic carbon (TNMOC) expressed in ppbC to the requirement that
individual target compounds be <0.2 ppbv for a series of analytical runs.

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Appendix C: Listing of Commercial Manufacturer a nd Re-Suppliers of
Specially Prepared Canisters

BRC/Rasmussen
17010 NW Skyline Blvd.
Portland, Oregon 97321
(503) 621-1435

Meriter

1790 Potrero Drive
San Jose, CA 95124
(408) 265-6482

Restek Corporation
110 Benner Circle
Bellefonte, PA 16823-8812
(814) 353-1300
(800) 356-1688

Scientific Instrumentation Specialists

P.O. Box 8941

815 Courtney Street

Moscow, ID 83843

(208) 882-3860

Graseby

500 Technology Ct.

Smyrna, Georgia 30082
(404) 319-9999
(800) 241-6898

XonTech Inc.
6862 Hayenhurst Avenue
Van Nuys, CA 91406
(818) 787-7380

41

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Appendix D: Listing of Commercial Suppliers of Permeation Tubes and
Systems

Kin-Tek
504 Laurel St.

Lamarque, Texas 77568
(409) 938-3627
(800) 326-3627

Vici Metronics, Inc.

2991 Corvin Drive
Santa Clara, CA 95051
(408) 737-0550

Analytical Instrument Development, Inc.
Rt. 41 and Newark Rd.

Avondale, PA 19311
(215) 268-3181

Ecology Board, Inc.
9257 Independence Ave.
Chatsworth, CA91311
(213) 882-6795

Tracor, Inc.

6500 Tracor Land
Austin, TX
(512) 926-2800

Metronics Associates, Inc.
3201 Porter Drive
Standford Industrial
Park Palo Alto, CA 94304
(415) 493-5632

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Table 1. Volatile Organic Compounds on the Title III Clean Air Amendment List—Membership in
Compendium Method TO-14A List and the SOW-CLP List of VOCs

Compound

CAS No.

BP (°C)1

v.p. (mmHg)1

MW1

TO-14A

CLP-SOW

Methyl chloride (chloromethane); CH3CI

74-87-3

-23.7

3.8 x 10

50.5

X

X

Carbonyl sulfide; COS

463-58-1

-50.0

3.7 x 10

60.1





Vinyl chloride (chloroethene); C2H3CI

75-01-4

-14.0

3.2 x 10

62.5

X

X

Diazomethane; CH2N2

334-88-3

-23.0

2.8 x 10

42.1





Formaldehyde; CH2O

50-00-0

-19.5

2.7 x 10

30





1,3-Butadiene; C4H6

106-99-0

-4.5

2.0 x 10

54



X

Methyl bromide (bromomethane); ChhBr

74-83-9

3.6

1.8 x 10

94.9

X

X

Phosgene; CCI2O

75-44-5

8.2

1.2 x 10

99





Vinyl bromide (bromoethene); C2H3Br

593-60-2

15.8

I.I x 10

107





Ethylene oxide; C2H4O

75-21-8

10.7

1.1 x 10

44





Ethyl chloride (chloroethane); C2H5CI

75-00-3

12.5

1.0 x 10

64.5

X

X

Acetaldehyde (ethanal); C2H4O

75-07-0

21.0

952

44





Vinylidene chloride (1,1-dichloroethylene);
C2H2CI2

75-35-4

31.7

500

97

X

X

Propylene oxide; C3H6O

75-56-9

34.2

445

58





Methyl iodide (iodomethane); CH3I

74-88-4

42.4

400

141.9





Methylene chloride; CH2CI2

75-09-2

40.0

349

84.9

X

X

Methyl isocyanate; C2H3NO

624-83-9

59.6

348

57.1





Allyl chloride (3-chloropropene); C3H5CI

107-05-1

44.5

340

76.5

X

X

Carbon disulfide; CS2

75-15-0

46.5

260

76





Methyl tert-butyl ether; C5H12O

1634-04-4

55.2

249

86





Propionaldehyde; C2H5CHO

123-38-6

49.0

235

58.1





Ethylidene dichloride (1,1-dichloroethane);
C2H4CI2

75-34-3

57.0

230

99

X



Chloroprene (2-chloro-1,3-butadiene);
C4H5CI

126-99-8

59.4

226

88.5





Chloromethyl methyl ether; C2H5CIO

107-30-2

59.0

224

80.5





Acrolein (2-propenal); C3H4O

107-02-8

52.5

220

56



X

1,2-Epoxybutane (1,2-butylene oxide);

c4h8o

106-88-7

63.0

163

72





Chloroform; CHCI3

67-66-3

61.2

160

119

X

X

Ethyleneimine (aziridine); C2H5N

151-56-4

56

160.0

43





1,1-Dimethylhydrazine; C2H8N2

57-14-7

63

157.0

60.0





Hexane; C6H14

110-54-3

69.0

120

86.2

X



1,2-Propyleneimine (2-methylaziridine);
C3H7N

75-55-8

66.0

112

57.1





Acrylonitrile (2-propenenitrile); C3H3N

107-13-1

77.3

100

53

X



Methyl chloroform (1,1,1 -trichloroethane);
C2H3CI3

71-55-6

74.1

100

133.4

X

X

Methanol; CH4O

67-56-1

65.0

92.0

32



X

Carbon tetrachloride; CCU

56-23-5

76.7

90.0

153.8

X

X

Vinyl acetate; C4H6O2

108-05-4

72.2

83.0

86



X

Methyl ethyl ketone (2-butanone); C4H8O

78-93-3

79.6

77.5

72



X

Benzene; C6H6

71-43-2

80.1

76.0

78

X

X

Acetonitrile (cyanomethane); C2H3N

75-05-8

82

74.0

41.0



X

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Compound

CAS No.

BP (°C)1

v.p. (mmHg)1

MW1

TO-14A

CLP-SOW

Ethylene dichloride (1,2-dichloroethane);
C2H4CI2

107-06-2

83.5

61.5

99

X

X

Triethylamine; C6H15N

121-44-8

89.5

54.0

101.2





Methylhydrazine; CH6N2

60-34-4

87. 8

49.6

46.1





Propylene dichloride (1,2-
dichloropropane); C3H6CI2

78-87-5

97.0

42.0

113

X

X

2,2,4-Trimethyl pentane CsHis

540-84-I

99.2

40.6

114





1,4-Dioxane (1,4-Diethylene oxide);
C4H8O2

123-91-1

101

37.0

88





Bis(chloromethyl) ether; C2H4CI2O

542-88-1

104

30.0

115





Ethyl acrylate; C5H8O2

140-88-5

100

29.3

100





Methyl methacrylate; C5H8O2

80-62-6

101

28.0

100.1





1,3-Dichloropropene; C3H4CI2 (cis)

542-75-6

112

27.8

111

X

X

Toluene; C7H8

108-88-3

111

22.0

92

X

X

Trichloroethylene; C2HCI3

79-01-6

87.0

20.0

131.4

X

X

1,1,2-Trichloroethane; C2H3CI3

79-00-5

114

19.0

133.4

X

X

Tetrachloroethylene; C2CI4

127-18-4

121

14.0

165.8

X

X

Epichlorohydrin (1 -chloro-2,3-epoxy
propane); C3H5CIO

106-89-8

117

12.0

92.5





Ethylene dibromide (1,2-dibromoethane);
C2H4Br2

106-93-4

132

11.0

187.9

X

X

N-Nitroso-N-methylurea; C2H5N3O2

684-93-5

124

10.0

103





2-Nitropropane; C3H7NO2

79-46-9

120

10.0

89





Chlorobenzene; C6H5CI

108-90-7

132

8.8

112.6

X

X

Ethylbenzene; CsHio

100-41-4

136

7.0

106

X

X

Xylenes (isomer & mixtures); CsHio

1330-20-7

142

6.7

106.2

X

X

Styrene; CsHs

100-42-5

145

6.6

104

X

X

p-Xylene; CsHio

106-42-3

138

6.5

106.2

X

X

m-Xylene; CsHio

108-38-3

139

6.0

106.2

X

X

Methyl isobutyl ketone (hexone); C6H12O

108-10-1

117

6.0

100.2





Bromoform (tribromomethane); CHBr3

75-25-2

149

5.6

252.8





1,1,2,2-Tetrachloroethane; C2H2CI4

79-34-5

146

5.0

167.9

X

X

o-Xylene; CsHio

95-47-6

144

5.0

106.2

X

X

Dimethylcarbamyl chloride; C3H6CINO

79-44-7

166

4.9

107.6





N-Nitrosodimethylamine; C2H6N2O

62-75-9

152

3.7

74





Beta-Propiolactone; C3H4O2

57-57-8

Decomposes
at 162

3.4

72





Cumene (isopropylbenzene); C9H12

98-82-8

153

3.2

120





Acrylic acid; C3H4O2

79-10-7

141

3.2

72





N,N-Dimethylformamide; C3H7NO

68-12-2

153

2.7

73





1,3-Propane sultone; C3H6O3S

1120-71-4

180/30mm

2.0

122.1





Acetophenone; CsHsO

98-86-2

202

1.0

120





Dimethyl sulfate; C2H6O4S

77-78-1

188

1.0

126.1





Benzyl chloride (a-chlorotoluene); C7H7CI

100-44-7

179

1.0

126.6

X

X

1,2-Dibromo-3-chloropropane; CsHsB^CI

96-12-8

196

0.80

236.4





Bis(2-Chloroethyl)ether; C4H8CI2O

111 -44-4

178

0.71

143





Chloroacetic acid; C2H3CIO2

79-11-8

189

0.69

94.5





Aniline (aminobenzene); C6H7N

62-53-3

184

0.67

93





44

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

Compound

CAS No.

BP (°C)1

v.p. (mmHg)1

MW1

TO-14A

CLP-SOW

1,4-Dichlorobenzene (p-); C6H4CI2

106-46-7

173

0.60

147

X

X

Ethyl carbamate (urethane); C3H7NO2

51-79-6

183

0.54

89





Acrylamide; C3H5NO

79-06-1

125/25 mm

0.53

71





N,N-Dimethylaniline; CsHuN

121-69-7

192

0.50

121





Hexachloroethane; C2CI6

67-72-1

Sublimes at
186

0.40

236.7





Hexachlorobutadiene; C4CI6

87-68-3

2I5

0.40

260.8

X

X

Isophorone; C9H14O

78-59-1

215

0.38

138.2





N-Nitrosomorpholine; C4H8N2O2

59-89-2

225

0.32

116.1





Styrene oxide; CsHsO

96-09-3

194

0.30

120.2





Diethyl sulfate; C4H10O4S

64-67-5

208

0.29

154





Cresylic acid (cresol isomer
mixture);C7H80

1319-77-3

202

0.26

108





o-Cresol; CzHsO

95-48-7

191

0.24

108





Catechol (o-hydroxyphenol); C6H6O2

120-80-9

240

0.22

110





Phenol; CeHeO

108-95-2

182

0.20

94





1,2,4-Trichlorobenzene; C6H3C13

120-82-1

213

0.18

181.5

X

X

Nitrobenzene; C6H5NO2

98-95-3

211

0.15

123





1Vapor pressure (v.p.), boiling point (BP) and molecularweight (MW) data from:







(a) D. L. Jones and J. Bursey, "Simultaneous Control of PM-10 and Hazardous Air Pollutants II: Rationale for Selection of
Hazardous Air Pollutants as Potential Particulate Matter," Report EPA-452/R-93/013, U. S. Environmental Protection Agency,
Research Triangle Park, NC. October 1992;

(b) R. C. Weber, P. A. Parker, and M. Bowser. Vapor Pressure Distribution of Selected Organic Chemicals, Report EPA-600/2-81-
021, U. S. Environmental Protection Agency, Cincinnati, OH, February 1981; and

(c) R. C. Weast, ed., "CRC Handbook of Chemistry and Physics," 59th edition, CRC Press, Boca Raton, 1979.



45

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

Table 2. Characteristic Masses (M/Z) Used for Quantifying the Title III Clean Air Act Amendment

Compounds

Compound

CAS No.

Primary Ion

Secondary Ion

Methyl chloride (chloromethane); CH3CI

74-87-3

50

52

Carbonyl sulfide; COS

463-S8-1

60

62

Vinyl chloride (chloroethene); C2H3CI

7S-01-4

62

64

Diazomethane; CH2N2

334-88-3

42

41

Formaldehyde; CH2O

50-00-0

29

30

1,3-Butadiene; C4H6

106-99-0

39

54

Methyl bromide (bromomethane); CHsBr

74-83-9

94

96

Phosgene; CCI2O

75-44-5

63

65

Vinyl bromide (bromoethene); C2H3Br

593-60-2

106

108

Ethylene oxide; C2H40

75-21-8

29

44

Ethyl chloride (chloroethane); C2H5CI

75-00-3

64

66

Acetaldehyde (ethanal); C2H40

75-07-0

44

29, 43

Vinylidene chloride (1,1-dichloroethylene); C2H2CI2

75-35-4

61

96

Propylene oxide; C3H6O

75-56-9

58

57

Methyl iodide (iodomethane); CH3I

74-88-4

142

127

Methylene chloride; CH2CI2

75-09-2

49

84, 86

Methyl isocyanate; C2H3NO

624-83-9

57

56

Allyl chloride (3-chloropropene); C3H5CI

107-05-1

76

OO

Carbon disulfide; CS2

75-15-0

76

44, 78

Methyl tert-butyl ether; C5H12O

1634-04-4

73

41, 53

Propionaldehyde; C2H5CHO

123-38-6

58

29, 57

Ethylidene dichloride (1,1-dichloroethane); C2H4CI2

75-34-3

63

65, 27

Chloroprene (2-chloro-1,3-butadiene); C4H5CI

126-99-8

88

53, 90

Chloromethyl methyl ether; C2H5CIO

107-30-2

45

29, 49

Acrolein (2-propenal); C3H4O

107-02-8

56

55

1,2-Epoxybutane (1,2-butylene oxide); C4H8O

106-88-7

42

41, 72

Chloroform; CHCI3

67-66-3

83

85, 47

Ethyleneimine (aziridine); C2H5N

151-56-4

42

43

1,1-Dimethylhydrazine; C2H8N2

57-14-7

60

45, 59

Hexane; CsH-m

110-54-3

57

CO

1,2-Propyleneimine (2-methylazindine); C3H7N

75-55-8

56

57, 42

Acrylonitrile (2-propenenitrile); C3H3N

107-13-1

53

52

Methyl chloroform (1,1,1 trichloroethane); C2H3CI3

71-55-6

97

99, 61

Methanol; CH4O

67-56-1

31

29

Carbon tetrachloride; CCI4

56-23-5

117

119

Vinyl acetate; C4H6O2

108-05-4

43

86

Methyl ethyl ketone (2-butanone); C4H8O

78-93-3

43

72

Benzene; C@H6

71-43-2

78

77,50

Acetonitrile (cyanomethane); C2H3N

75-05-8

41

40

Ethylene dichloride (1,2-dichloroethane); C2H4CI2

107-06-2

62

64, 27

46

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

Compound

CAS No.

Primary Ion

Secondary Ion

Triethylamine; CgHisN

121-44-8

86

58, 101

Methylhydrazine; CH6N2

60-34-4

46

31, 45

Propylene dichloride (1,2-dichloropropane); C3H6CI2

78-87-5

63

41, 62

2,2,4-Trimethyl pentane; CsH-is

540-84-1

57

41, 56

1,4-Dioxane (1,4 Diethylene oxide); C4H8O2

123-91-1

88

58

Bis(chloromethyl) ether; C2H4CI2O

542-88-1

79

49, 81

Ethyl acrylate; C5H8O2

140-88-5

55

73

Methyl methacrylate; C5H8O2

80-62-6

41

69, 100

1,3-Dichloropropene; C3H4CI2 (cis)

542-75-6

75

39, 77

Toluene; C7H8

108-88-3

91

92

Trichloethylene; C2HCI3

79-01-6

130

132, 95

1,1,2-Trichloroethane; C2H3CI3

79-00-5

97

83, 61

Tetrachloroethylene; C2CI4

127-18-4

166

164, 131

Epichlorohydrin (l-chloro-2,3-epoxy propane); C3H5CIO

106-89-8

57

49, 62

Ethylene dibromide (1,2-dibromoethane); C2H4Br2

106-93-4

107

109

N-Nitrso-N-methylurea; C2H5N3O2

684-93-5

60

44, 103

2-Nitropropane; C3H7NO2

79-46-9

43

41

Chlorobenzene; C6H5CI

108-90-7

112

77, 114

Ethylbenzene; CsHio

100-41-4

91

106

Xylenes (isomer & mixtures); CsHio

1330-20-7

91

106

Styrene; CsHs

100-42-5

104

78, 103

p-Xylene; CsHio

106-42-3

91

106

m-Xylene; CsHio

108-38-3

91

106

Methyl isobutyl ketone (hexone); C6H12O

108-10-1

43

58, 100

Bromoform (tribromomethane); CHBr3

75-25-2

173

171, 175

1,1,2,2-Tetrachloroethane; C2H2CI4

79-34-5

83

85

o-Xylene; CsHio

95-47-6

91

106

Dimethylcarbamyl chloride; C3H6CINO

79-44-7

72

107

N-Nitrosodimethylamine; C2H6N2O

62-75-9

74

42

Beta-Propiolactone; C3H4O2

57-57-8

42

43

Cumene (isopropylbenzene); C9H12

98-82-8

105

120

Acrylic acid; C3H4O2

79-10-7

72

45, 55

N,N-Dimethylformamide; C3H7NO

68-12-2

73

42, 44

1,3-Propane sultone; C3H6O3S

1120-71-4

58

65, 122

Acetophenone; CsHsO

98-86-2

105

77,120

Dimethyl sulfate; C2H6O4S

77-78-1

95

66,96

Benzyl chloride (a-chlorotoluene); C7H7CI

100-44-7

91

126

1,2-Dibromo-3-chloropropane; CsHsB^CI

96-12-8

57

155, 157

Bis(2-Chloroethyl)ether; C4H8CI2O

111-44-4

93

63, 95

Chloroacetic acid; C2H3CIO2

79-11-8

50

45, 60

Aniline (aminobenzene); C6H7N

62-53-3

93

66

1,4-Dichlorobenzene (p-); C6H4CI2

106-46-7

146

148, 111

47

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

Compound

CAS No.

Primary Ion

Secondary Ion

Ethyl carbamate (urethane); C3H7NO2

51-79-6

31

44, 62

Acrylamide; C3H5NO

79-06-1

44

55, 71

N,N-Dimethylaniline; CsHuN

121-69-7

120

77, 121

Hexachloroethane; C2CI6

67-72-1

201

199, 203

Hexachlorobutadiene; C4CI6

87-68-3

225

227, 223

Isophorone; C9H14O

78-59-1

82

138

N-Nitrosomorpholine; C4H8N2O2

59-89-2

56

86, 116

Styrene oxide; CsHsO

96-09-3

91

120

Diethyl sulfate; C4H10O4S

64-67-5

45

59, 139

Cresylic acid (cresol isomer mixture); CzHsO

1319-77-3





o-Cresol; CzHsO

95-48-7

108

107

Catechol (o-hydroxyphenol); C6H6O2

120-80-9

110

64

Phenol; CgHgO

108-95-2

94

66

1,2,4-Trichlorobenzene; C6H3CI3

120-82-1

180

182, 184

Nitrobenzene; C6H5NO2

98-95-3

77

51, 123

Table 3. Required BFB Key Ions and Ion Abundance Criteria

Mass

Ion Abundance Criteria1

50

8.0 to 40.0 Percent of m/e 95

75

30.0 to 66.0 Percent of m/e 95

95

Base Peak, 100 Percent Relative Abundance

96

5.0 to 9.0 Percent of m/e 95 (See note)

173

Less than 2.0 Percent of m/e 174

174

50.0 to 120.0 Percent of m/e 95

175

4.0 to 9.0 Percent of m/e 174

176

93.0 to 101.0 Percent of m/e 174

177

5.0 to 9.0 Percent of m/e 176

1 All ion abundances must be normalized to m/z 95, the nominal base
peak, even though the ion abundance of m/z 174 may be up to 120
percent that of m/z 95.

Table 4. Method Detection Limits (MDLs)1

TO-14A List

Lab #1, SCAN

Lab #2, SIM

Benzene

0.34

0.29

Benzyl Chloride





Carbon tetrachloride

0.42

0.15

Chlorobenzene

0.34

0.02

Chloroform

0.25

0.07

1,3-Dichlorobenzene

0.36

0.07

1,2-Dibromoethane



0.05

1,4-Dichlorobenzene

0.70

0.12

1,2-Dichlorobenzene

0.44



1,1-Dichloroethane

0.27

0.05

48

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

TO-14A List

Lab #1, SCAN

Lab #2, SIM

1,2-Dichloroethane

0.24



1,1-Dichloroethene



0.22

cis-1,2-Dichloroethene



0.06

Methylene chloride

1.38

0.84

1,2-Dichloropropane

0.21



cis-1,3-Dichloropropene

0.36



trans-1,3-Dichloropropene

0.22



Ethylbenzene

0.27

0.05

Chloroethane

0.19



T richlorofluoromethane





1,1,2-T richloro-1,2,2-trifluoroethane





1,2-Dichloro-1,1,2,2-
tetrafluoroethane





Dichlorodifluoromethane





Hexachlorobutadiene





Bromomethane

0.53



Chloromethane

0.40



Styrene

1.64

0.06

1,1,2,2-T etrachloroethane

0.28

0.09

Tetrachloroethene

0.75

0.10

Toluene

0.99

0.20

1,2,4-Trichlorobenzene





1,1,1-Trichloroethane

0.62

0.21

1,1,2-Trichloroethane

0.50



Trichloroethene

0.45

0.07

1,2,4-Trimethyl benzene





1,3,5-Trimethyl benzene





Vinyl Chloride

0.33

0.48

m,p-Xylene

0.76

0.08

o-Xylene

0.57

0.28

1 Method Detection Limits (MDLs) are defined as the product of the
standard deviation of seven replicate analyses and the student's "t" test
value for 99% confidence. For Lab #2, the MDLs represent an average
over four studies. MDLs are for MS/SCAN for Lab #1 and for MS/SIM for
Lab #2.

Table 5. Summary of EPA Data on Replicate Precision (RP) from EPA Network Operations1

Identification

EPA's Urban Air Toxics Monitoring
Program (UATMP)

EPA's Toxics Air Monitoring
Stations (TAMS)

%RP

#

ppbv

%RP

#

ppbv

Dichlorodifluoromethane

-



-

13.9

47

0.9

Methylene chloride

16.3

07

4.3

19.4

47

0.6

1,2-Dichloroethane

36.2

31

1.6

-

-

-

1,1,1-Trichloroethane

14.1

44

1.0

10.6

47

2.0

49

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#EPA	Method TO-15

United States	mm**.**.

Environmental Protection	DOCGI1ll)9r 2015	VOvS

Identification

EPA's Urban Air Toxics Monitoring
Program (UATMP)

EPA's Toxics Air Monitoring
Stations (TAMS)



%RP

#

ppbv

%RP

#

ppbv

Benzene

12.3

56

1.6

4.4

47

1.5

Trichloroethene

12.8

08

1.3

-

-

-

Toluene

14.7

76

3.1

3.4

47

3.1

Tetrachloroethene

36.2

12

0.8

-

-

-

Chlorobenzene

20.3

21

0.9

-

-

-

Ethylbenzene

14.6

32

0.7

5.4

47

0.5

m-Xylene

14.7

75

4.0

5.3

47

1.5

Styrene

22.8

592

1.1

8.7

47

0.22

o-Xylene

-



-

6.0

47

0.5

p-Xylene

-











1,3-Dichlorobenzene

49.1

06

0.6

-

-

-

1,4-Dichlorobenzene

14.7

14

6.5

-

-

-

1 Denotes the number of replicate or duplicate analysis used to generate the statistic. The replicate precision is
defined as the mean ratio of absolute difference to the average value.

2Styrene and o-xylene coelute from the GC column used in UATMP. For the TAMS entries, both values were below
detection limits for 18 of 47 replicates and were not included in the calculation.

Table 6. Audit Accuracy (AA) Values1 for Selected Compendium Method TO-14A Compounds

Selected Compounds From TO-14A List

FY-88 TAMS AA(%), N=30

FY-88 UATMP AA(%), N=3

Vinyl chloride

4.6

17.9

Bromomethane

-

6.4

T richlorofluoromethane

6.4

-

Methylene chloride

8.6

31.4

Chloroform

-

4.2

1,2-Dichloroethane

6.8

11.4

1,1,1-Trichloroethane

18.6

11.3

Benzene

10.3

10.1

Carbon tetrachloride

12.4

9.4

1,2-Dichloropropane

-

6.2

Trichloroethene

8.8

5.2

Toluene

8.3

12.5

Tetrachloroethene

6.2

-

Chlorobenzene

10.5

11.7

Ethylbenzene

12.4

12.4

o-Xylene

16.2

21.2

1 Audit accuracy is defined as the relative difference between the audit measurement result and its nominal value
divided by the nominal value. N denotes the number of audits averaged to obtain the audit accuracy value.
Information is not available for other TO-14A compounds because they were not present in the audit materials.

50

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

To AC

To AC

Figure 1. Sampler configuration for subatmospheric pressure or pressurized canister sampling.

51

-------


United States
Environmental Protection
Agency

Method TO-15

December 2015

VOCs

TIMEW
SWTTCH

—qr

115 AC

PUNf>

lt»K
iWW.

U f:-]

40frf 100K

40mM. 450 V DC

cawaam

G»i*»e«a» Ct aid Ct - 40 (A 4S0 V0C (Sprop* TMd 17H or hi mm*}
¦amir R( and R* - ft* ML 3* Were!*®

Hod* 0i ad Bt - 10B0 WW, Z& i PCA, SK Ml m aqaiaMl

WHITE

(a). Simple Circuit for Operating Magnelatch Valve

T15 V AC

BtMpt* flntifef - 300 PfW» 1J A (SC* SK .311® or aqintilant)

ceo* oi «m m - ion m. ts a pe*, k ro «

Qapodti* Ci - 200 uf, 250 V0C (Spcagu® Mam T»» liffi i» qidM)

Dspocllnr Cf — J® uf, 400 \®C Mm—Pakrtz&i |Spnfm Mum "MM 1MK at cwlMM)

(Way - tWJQO rtm oS, 13 ma Uf Mai and SrgmMd, KCP 3. or sqtfnM)
" "" ¦ Ri mm R* - OS ¦#«, x '	

Wt-WBIP

(b). Improved Circuit Designed to Handle Power Interruptions

Figure 2. Electrical pulse circuits for driving Skinner magnelatch solenoid valve with mechanical

timer.

52

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

Figure 3. Alternative sampler configuration for pressurized canister sampling.

53

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oEPA

United States
Environmental Protection
Agency

Method TO-15

December 2015

VQCs

PL1 TRANSFER TO THE rRECQMCEflimilOM TRAP

SAMPLE GAS
FLOW

' AIR SAMPLE IN

STAQE2: DRY PURGING

DRYHEUUM ftPSOBiiMT TBAP

PURGE QA3



t li

T

AT NEAR AMBIENT
THNPERATURE I

PURGE GAS
PLUS WATER

GMREft

GAS IN

CARRIER

OAS IN

STAGE S: TRAP DESORPTION - ANALYTE TRANSFER TO GC COLUMN

CARRIER OAS IN'

ADSOHBEtfF TRAP

VJ

(HOT)

Figure 4. Illustration of three stages of dry purging of adsorbent trap.

54

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#EPA	Method TO-15

United States
Environrr
Agency

Environmental Promotion	December 2015	VOCUl

0 100 200 300 400 500 600 700 800 900 1000 1100

PURGE VOLUME, ml
Figure 5. Residual water vapor on VOC concentrator vs. dry He purge volume.

55

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#EPA	Method TO-15

United States
Environrr
Agency

Environmental Promotion	December 2015	VOCUl

56

-------
#EPA

United States
Environmental Protection
Agency

Method TO-15

December 2015

VOCs

Filament

Column
Effluent

J End Cap

X





( Ring

Supplementary



rf Voltage

V

\ End Cap





^^"^^Electron Multiplier

Figure 7. Simplified diagram of an ion trap mass spectrometer.

57

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#EPA	Method TO-15

United States
Environrr
Agency

Environmental Promotion	December 2015	VOCUl

Figure 8. Schematic diagram of calibration system and manifold for (a) analytical system
calibration, (b) testing canister sampling system and (c) preparing canister transfer standards.

58

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

C OMPENDIOI METHOD TO-15
CANISTER SAMPLING FIELD TEST DATA SHEET
A.GENERAL INFORMATION

SITE LOC ATION": 		SHIPPING DATE 	

SITE .ADDRESS:		CANISTER SERLAL NO.:

		SAMPLER ID 	

SAMPLING DATE:		OPERATOR: 	

CANISTER LEAK
CHECK DATE:

B. SAMPLING ENTO R1LVTI ON

TEMPERATURE	PRESSURE



INTERIOR

AMBIENT

MjAXIMUM

MMMtJM

START









STOP









SAMPLING TIMES

FLOW RATES



LOCAL TIME

ELAPSED HME
METER READING

START





STOP





MANIFOLD

FLOW RATE

CANISTER
FLOW RATE

FLOW
CONTROLLER
READOUT













SAMPLING SYSTEM CERTIFICATION DATE:
QUARTERLY KECERTinCATION DATE:	

C. LABORATORY INFORMATION

DATA RECEIVED 	

RECEIVED BY:	

INITIAL PRESSURE: _
FINAL PRESSURE: _

DILUTION FACTOR _
-ANALYSIS
GC -FID-EC D DATE: _
GC-MSD-SCAXDATE
GC-MSD-SEvI DATE: _
RESULTS"-:	

GC-FID-EC D _

GC-MSD-SCAN:
GC-MSD-SM:

SIGNATURE TITLE
Figure 9. Canister sampling field test data sheet (FTDS).

59

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

60

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

Pressure
RefltJater

He

Canrtar

Gas

6-Port

C*twi»ati3|jraplie
Vfelva

Ctyogenc
i rapping Unit

Pressors
Rsflutatarst

Gas
Purilsre

OV-1 Capillary Column
(0.32 w > 50 m)

Low Dead-Vblurae
Tm (Optimal)

Flameta

S x—^ r_r™j.,.,.|_ dim*

Ionization 1
(FID) j

i i

FIcwRestrictor
(optional)

Miss Spectrometer

h SCAN cr SIM Mo*

Figure 11. Canister analysis utilizing GC/MS/SCAN/SIM analytical system with optional flame
ionization detector with 6-port chromatographic valve in the sample desorption mode.

[Alternative analytical system illustrated in Figure 16.]

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

mtE

(a). Certified Sampler

Figure 12. Example of humid zero air test results for a clean sample canister (a) and a

contaminated sample canister (b).

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

Figure 13. Diagram of design for internal standard addition.

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#EPA	Method TO-15

United States
Environrr
Agency

Environmental Promotion	December 2015	VOCUl

Figure 14. Water method of standard preparation in canisters.

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oEPA

United States
Environmental Protection
Agency

Method TO-15

December 2015

VQCs

f

O™

FC-2





I

Humidifier

Exhaust:

11

Calibration Manifold i

Calibration Zero Mr
Gas Cylinder Cylinder

To

Auto. Temp
Control

T =Themiocoiipte
F sZero Oead Vol. Fit.
FC = Row Controller
S = Solenoid Valve

Heated Enclosure

Figure 15. Diagram of the GC/MS analytical system.

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#EPA	Method TO-15

Environment!!1 Prat.ction	DlC»WlbW 2015	VOCS

STATUS:

TRAP 1: Sampling
TRAP 2: Desorbing

		

HELIUM



i TO GCI

--j—				

| DETECTOR

STIRLING CYCLE COOLER

Figure 16. Sample flow diagram of a commercially available concentrator showing the
combination of multisorbent tube and cooler (Trap 1 sampling; Trap 2 desorbing).

66

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