EPA/625/R-96/010b
      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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                                       Method TO-15
                                     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), which was prepared 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, Center for Environmental Research
Information (CERI), and Frank F. McElroy, 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:

         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, Gary, 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.

Author(s)
    •    William A. McClenny, U.S. 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, U.S. EPA, NRMRL, Cincinnati, OH

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

                                        DISCLAIMER

This Compendium has been subjected to the Agency's peer and administrative review, and it has
been approved for publication as an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.

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                                       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)

                                   TABLE OF CONTENTS
                                                                                          Page

1.   Scope	      15-1

2.   Summary of Method                                                                    15-2

3.   Significance	      15-3

4.   Applicable Documents  	      15-4
    4.1  ASTM Standards	      15-4
    4.2  EPA Documents	      15-4

5.   Definitions	      15-4

6.   Interferences and Contamination	      15-6

7.   Apparatus and Reagents  	      15-6
    7.1  Sampling Apparatus  	      15-6
    7.2  Analytical Apparatus	      15-8
    7.3  Calibration System and Manifold Apparatus 	     15-10
    7.4  Reagents	     15-10

8.   Collection of Samples in Canisters	     15-10
    8.1  Introduction	     15-10
    8.2  Sampling System Description	     15-11
    8.3  Sampling Procedure	     15-12
    8.4  Cleaning and Certification Program 	     15-14

9.   GC/MS Analysis of Volatiles from Canisters	     15-16
    9.1  Introduction	     15-16
    9.2  Preparation of Standards	     15-17

10.  GC/MS Operating Conditions	     15-21
    10.1 Preconcentrator 	     15-21
    10.2 GC/MS System 	     15-22
    10.3 Analytical Sequence	     15-22
    10.4 Instrument Performance Check	     15-23
    10.5 Initial Calibration	     15-23
    10.6 Daily Calibration	     15-27
    10.7 Blank Analyses 	     15-27
    10.8 Sample Analysis  	     15-28

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                             TABLE OF CONTENTS (continued)

                                                                                         Page

11.  Requirements for Demonstrating Method Acceptability for VOC Analysis from
    Canisters  	     15-31
    11.1 Introduction	     15-31
    11.2 Method Detection Limit	     15-31
    11.3 Replicate Precision  	     15-31
    11.4 Audit Accuracy  	     15-32

12.  References	     15-32

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                                        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)
1. 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 entitled: 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 cocollected 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 over time (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
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Method TO-15	VOCs

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 other in terms of making
standards. However, this is not always the case and some compound standards will be troublesome. The reader
is referred to the Section 9.2 on standards for guidance.  Calibration of compounds such as formaldehyde,
diazomethane, and many of the others represents a challenge.

1.5  Compendium Method TO-15  should be considered for use when a subset of the 97 Title III VOCs constitute
the  target list.  Typical situations involve ambient air testing associated with the permitting procedures for
emission sources. In this case sampling and analysis of VOCs is performed to determine the impact of dispersing
source emissions in the surrounding areas. Other important applications are prevalence and trend monitoring for
hazardous VOCs in urban areas and risk assessments downwind of industrialized or source-impacted areas.

1.6  Solid  adsorbents can be used in lieu of canisters for sampling of VOCs, provided the solid adsorbent
packings, usually multisorbent packings in metal or glass tubes, can meet the performance criteria specified in
Compendium Method TO-17 which specifically addresses the use of multisorbent packings.  The two sample
collection techniques are different but become  the same  upon movement of the sample from the collection
medium (canister or multisorbent tubes)  onto the sample concentrator.  Sample collection directly from the
atmosphere by automated gas chromatographs can be used in lieu of collection in canisters or on solid adsorbents.
2. Summary of Method

2.1 The atmosphere is sampled by introduction of air into a specially-prepared stainless steel canister.  Both
subatmospheric pressure and pressurized sampling modes use an initially evacuated canister. A pump ventilated
sampling line is used during sample collection with most commercially available samplers.  Pressurized sampling
requires an additional pump to provide positive pressure to the sample canister. A sample of air is drawn through
a sampling train comprised of components that regulate the rate and duration of sampling into the pre-evacuated
and passivated canister.

2.2 After the air sample is collected, the canister valve is closed, an identification tag is attached to the canister,
and the canister is transported to the laboratory for analysis.

2.3 Upon receipt at the laboratory, the canister tag data is recorded and the canister is stored until analysis.
Storage times of up to thirty days have been demonstrated for many of the VOCs (5).

2.4 To analyze the sample, a known volume of sample is directed from the canister through a solid multisorbent
concentrator. A portion of the water vapor in the sample breaks through the concentrator during sampling, to a
degree depending on the multisorbent composition, duration of sampling, and other factors.  Water content of
the sample can be further reduced by dry purging the  concentrator with helium while retaining target compounds.
After the concentration and drying steps are completed, the VOCs are thermally desorbed, entrained in a carrier
gas stream, and then focused in a small volume by trapping on a reduced temperature trap or small volume
multisorbent trap. The sample  is then released by thermal desorption and carried onto a gas chromatographic
column for separation.

As a simple alternative to the multisorbent/dry purge water management technique, the amount of water vapor
in the sample can be reduced below any threshold for affecting the proper operation of the analytical system by
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VOCs	Method TO-15

reducing the sample size. For example, a small sample can be concentrated on a cold trap and released directly
to the gas chromatographic column. The reduction in sample volume may require an enhancement of detector
sensitivity.

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 (BCD), 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
January 1999        Compendium of Methods for Toxic Organic Air Pollutants            Page 15-3

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Method TO-15	VOCs

     adsorbents) that are often used. This method lists performance criteria that these alternatives must meet
     to be acceptable alternatives for monitoring ambient VOCs.
   • 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, andE355. Aside from the definitions given below,
all pertinent abbreviations and symbols are defined within this document at point of use.}

5.1  Gauge Pressure—pressure measured with reference to the surrounding atmospheric pressure, usually
expressed in units of kPa or psi. Zero gauge pressure is equal to atmospheric (barometric) pressure.
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VOCs	Method TO-15

5.2 Absolute Pressure—pressure measured with reference to absolute zero pressure, usually expressed in units
of kPa, or psi.

5.3 Cryogen—a refrigerant used to obtain sub-ambient temperatures in the VOC concentrator and/or on front
of the analytical column. Typical cryogens are liquid nitrogen (bp -195.8°C), liquid argon (bp -185.7°C), and
liquid CO2(bp-79.5°C).

5.4 Dynamic Calibration—calibration of an analytical system using calibration gas standard concentrations
in a form identical or very similar to the samples to be analyzed and by introducing such standards into the inlet
of the sampling or analytical system from a manifold through which the gas standards are flowing.

5.5 Dynamic Dilution—means of preparing calibration mixtures in which standard gas(es) from pressurized
cylinders are continuously blended with humidified zero air in a manifold so that a flowing stream of calibration
mixture is available at the inlet of the analytical system.

5.6 MS-SCAN—mass spectrometric mode of operation in which the gas chromatograph (GC) is coupled to a
mass spectrometer (MS) programmed to SCAN all ions repeatedly over a specified mass range.

5.7 MS-SIM—mass spectrometric mode of operation in which the GC is coupled to a MS that is programmed
to scan a selected number of ions repeatedly [i.e., selected ion monitoring (SIM) mode].

5.8 Qualitative Accuracy—the degree of measurement accuracy required to correctly  identify compounds with
an analytical system.

5.9  Quantitative Accuracy—the degree of measurement accuracy required  to correctly measure the
concentration of an identified compound with an analytical  system with known uncertainty.

5.10 Replicate Precision—precision determined from two canisters filled from the same air mass over the same
time period and determined as the absolute value of the difference between the analyses of canisters divided by
their average value and expressed as a percentage (see Section 11 for performance criteria for replicate precision).

5.11 Duplicate Precision—precision determined from the analysis of two samples taken from the same canister.
The duplicate precision is determined as the absolute value of the difference between the  canister analyses divided
by their average value and expressed as a percentage.

5.12 Audit Accuracy—the difference between the analysis of a sample provided in an audit canister and the
nominal value as determined by the audit authority, divided by the audit value and expressed as a percentage (see
Section 11 for performance criteria for audit accuracy).
6. Interferences and Contamination

6.1  Very volatile compounds, such as chloromethane and vinyl chloride can display peak broadening and
co-elution with other species if the compounds are not delivered to the GC column in a small volume of carrier
gas.  Refocusing of the sample after collection on the primary trap, either on a separate focusing trap or at the
head of the gas chromatographic column, mitigates this problem.
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Method TO-15	VOCs

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-l4A 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).
     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 (20^0°C) and humidity.
     7.1.1.5  Particulate Matter Filter. 2-^m sintered stainless steel in-line filter.
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VOCs	Method TO-15

      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.

[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.
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Method TO-15	VOCs

      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-III (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.
      7.2.1.7.2An example of the effectiveness of dry purging is shown in Figure 5. The multisorbent used in
this case is Tenax/Ambersorb 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.
      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 ID. 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.
      7.2.2.3.1Linear 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
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VOCs	Method TO-15

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.
      7.2.2.3.2Ion 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 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 integrat-
ing 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.
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Method TO-15	VOCs

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.
   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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   8.2.2  Pressurized Sampling [see Figure 1 (with metal bellows type pump)].
      8.2.2.1  Pressurized sampling is used when longer-term integrated samples or higher volume samples are
required.  The sample is collected in a canister using a pump and flow control arrangement to achieve a typical
101-202 kPa (15-30 psig) final canister pressure. For example, a 6-liter evacuated canister can be filled at 10
mL/min for 24 hours to achieve a final pressure of 144 kPa (21 psig).
      8.2.2.2 In pressurized canister sampling, a metal bellows type pump draws in air from the sampling
manifold to fill and pressurize the sample canister.
   8.2.3 All Samplers.
      8.2.3.1 A flow control device is chosen to maintain a constant flow into the canister over the desired
sample period. This flow rate is determined so the canister is filled (to about  88.1 kPa for subatmospheric
pressure sampling or to about one atmosphere above ambient pressure for pressurized sampling) over the desired
sample period. The flow rate can be calculated by:

                                           F -   PxV
                                                T x 60

   where:

         F = flow rate, mL/min.
         P = final canister pressure, atmospheres absolute. P is approximately equal to
                                          kPa gauge    ,
                                             101.2    +

         V = volume of the canister, mL.
         T = sample period, hours.

For example, if a 6-L canister is to be filled to 202 kPa (2 atmospheres) absolute pressure in 24 hours, the flow
rate can be calculated by:
                                   „    2 x 6000    „ .   T .  .
                                   b  =	  =  8.3 mL/min
                                        24 x 60

      8.2.3.2  For automatic operation, the timer is designed to start and stop the pump at appropriate times for
the desired sample period.  The timer must also control the solenoid valve, to open the valve when starting the
pump and to close the valve when stopping the pump.
      8.2.3.3 The use of the Skinner Magnelatch valve (see Figure 2) avoids any substantial temperature rise
that would occur with a conventional, normally closed solenoid valve that would have to be energized during the
entire sample period.  The temperature rise in the valve could cause outgassing of organic compounds from the
Viton® valve seat material. The Skinner Magnelatch valve requires only a brief electrical pulse to open or close
at the appropriate start and stop times and therefore experiences no temperature  increase. The pulses may  be
obtained either with an electronic timer that can be programmed for short (5 to 60  seconds) ON periods, or with
a conventional mechanical timer and a special pulse circuit.  A simple electrical pulse circuit for operating the
Skinner Magnelatch solenoid valve with a conventional mechanical timer is illustrated in Figure 2(a). However,
with this simple circuit, the valve  may operate unreliably during brief power interruptions or if the timer is
manually switched on and off too fast. A better circuit incorporating a time-delay relay to provide more reliable
valve operation is shown in Figure 2(b).
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Method TO-15	VOCs

     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 I]

   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.
   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.]
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VOCs	Method TO-15

    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.]

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.
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Method TO-15                                                                               VOCs
[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 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.
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VOCs	Method TO-15

[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 refocussed on a cold trap. This trap is heated and the VOCs are thermally desorbed onto
the head of the capillary column. The VOCs are refocussed 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.
    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.
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Method TO-15	VOCs

      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 or ion 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 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.
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VOCs	Method TO-15

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 Cylinders) 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.
   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-ds, and 1,4-difluorobenzene at 10 ppmv each in humidified zero air to be added
to the sample or calibration standard.  500 uL 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.
                      AJ   •£• u  /^        (Original Cone.) (Std. Gas Flowrate)
                      Manifold  Cone. = -—	—	-
                                         (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:
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Method TO-15 _ VOCs


                Manifold Cone  = (10 PPm)(l mL/min)(1000 ppb/1 ppm)  = 1Q
                                       (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.
     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 A A 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:
                                                         (V
                                  Concentration, mg/L =
   where:      Va =  Volume of liquid neat standard injected into the flask, uL.
                 d =  Density of the liquid neat standard, mg/uL.
               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 ofaliquot(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).
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VOCs
                                                              Method TO-15
     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.
     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:
                                                  Volume,,
                           Concentration, ppbv =
                                    "standard
                            Volumedilution
x 109
[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:

                                            v =
     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 arm).
                 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.
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Method TO-15	VOCs

   9.2.6 Standard Preparation by Water Methods.

[Note: Standards maybe 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 arm) 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.

[Note:  Extra effort should be made to minimize possible areas of dead volume to maximize transfer of
analytesfrom 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.

    10.1.1  Sample Collection Conditions

    Cryogenic Trap                                 Adsorbent Trap
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VOCs	Method TO-15

   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 pre concentration 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              120 ° C (24 hrs)       Initial bakeout
   Variable (24 hrs)
   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 um film thickness fused silica column with refocusing on the column.

   Item                     Condition

   Carrier Gas:                Helium
   Flow Rate:                Generally 1-3 mL/min as recommended by manufacturer
   Temperature Program:      Initial Temperature:      -50°C
                             Initial Hold Time:       2 min
                             Ramp Rate:             8°  C/min
                             Final Temperature:      200°C
                             Final Hold Time:        Until all target compounds elute.

   10.2.3 The following are the recommended mass spectrometer conditions:

      Item            Condition
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Method TO-15	VOCs

     Electron Energy:  70 Volts (nominal)
     Mass Range:     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.
    Scan Time:         To give at least 10 scans per peak, not to exceed 1 second per scan].

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.
    10.4.5  Corrective Action.  If the BFB acceptance criteria are not met, the MS must be retimed.  It may be
necessary to clean the ion source, or quadrupoles, or take other necessary actions to achieve the acceptance
criteria.
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VOCs	Method TO-15

    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 (RRF).  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:
                                                   AC
                                           RRF =
                                                     X  IS
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Method TO-15 _ VOCs

     where:     RRF = Relative response factor.
                  Ax = Area of the primary ion for the compound to be measured, counts.
                  A1S = Area of the primary ion for the internal standard, counts.
                  C1S = 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 oilfield 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:
                                         RRF  =     i
     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:

                                     %RSD  =    RRF x  100
                                               RRF

     and
                                 SD
                                    RRF
                                          \
 N
£
(RRF;  -  RRF)Z
    N  - 1
     where:           SDj^ =  Standard deviation of initial response factors (per compound).
                           j =  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:
                                                  RT
                                          RRT =
                                                  RT
     where:     RTC=  Retention time of the target compound, seconds
                RT1S =  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:
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VOCs                                                                             Method TO-15
                                         RRT  =
                                                    RRT
     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 (Y) for Internal Standard. Calculate the mean area response (Y) for
each internal standard compound over the initial  calibration range using the following equation:
     where:     Y =  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:
                                          _    "  RT.
                                          RT =     ^
     where:   RT =  Mean retention time, seconds
              RT =  Retention time for the internal standard for each initial calibration standard, seconds.
    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 withiin 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.
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Method TO-15                                                                              VOCs
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:
                                           RRF  - RRF.
                                   %D = 	^	L x 100
                                               RRF.
     where:          RRFC= RRF of the compound in the continuing calibration standard.
                     RRF; = 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
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VOCs	Method TO-15

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  arm.

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.
    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
January 1999         Compendium of Methods for Toxic Organic Air Pollutants           Page 15-27

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Method TO-15	VOCs

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.
      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.
                                          c   _ A/^DF
     where:       Cx =  Compound concentration, ppbv.
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VOCs	Method TO-15

                  Ax =  Area of the characteristic ion for the compound to be measured, counts.
                  A1S =  Area of the characteristic ion for the specific internal standard, counts.
                  C1S =  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.
[Note:  The equation above is valid under the condition that the volume (-500 f^L) 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 andRTs
in the sample are evaluated against the corresponding internal standard area responses andRTs 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
January 1999         Compendium of Methods for Toxic Organic Air Pollutants           Page 15-29

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Method TO-15	VOCs

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.
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:
                               percent difference = - — - x 100
    where:          Xj =  First measurement value.
                   x2 =  Second measurement value.
                   x =  Average of the two values.
Page 15-30           Compendium of Methods for Toxic Organic Air Pollutants        January 1999

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VOCs                                                                             Method TO-15
    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 VOCs.  A primary influence on
precision is the concentration level of the compound of interest in the sample, i.e., the precision degrades as the
concentration approaches the detection limit.  A conservative measure was obtained from replicate analysis of
"real world" canister samples from the TAMS and UATMP networks.  These data are summarized in Table 5
and suggest that a replicate precision value of 25 percent can be achieved for each of the target compounds.

11.4 Audit Accuracy

    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:
                    •   ,-.  A         0/     Spiked Value - Observed Value   iriri
                   Audit Accuracy, % = —	 x 100
                                                  Spiked Value

    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.
12. References

1.  Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: Method TO-
14A, Second Edition, U. S. Environmental Protection Agency, Research Triangle Park, NC, EPA 600/625/R-
96/01 Ob, January  1997.

2.  Winberry, W. T., Jr., et al., Statement-of-Work (SOW) for the Analysis of Air Toxics From Superfund Sites,
U. S. Environmental Protection Agency, Office of Solid Waste, Contract Laboratory Program, Washington, D.C.,
Draft Report, June 1990.

3.   Coutant, R.W., Theoretical Evaluation of Stability of Volatile Organic  Chemicals and Polar Volatile
Organic Chemicals in Canisters, U. S. Environmental Protection Agency, EPA Contract No. 68-DO-0007,
Work Assignment No. 45, Subtask 2, Battelle, Columbus, OH, June 1993.

4.  Kelly, T.J., Mukund, R., Gordon, S.M., and Hays, M.J., Ambient Measurement Methods and Properties of
the 189 Title III Hazardous Air Pollutants, U. S.  Environmental Protection Agency, EPA Contract No. 68-DO-
0007, Work Assignment 44, Battelle, Columbus, OH, March 1994.

5.   Kelly T. J. and Holdren, M.W., "Applicability of Canisters for Sample Storage in the Determination of
Hazardous Air Pollutants," Atmos. Environ., Vol. 29, 2595-2608, May 1995.

6.  Kelly, T.J.,  Callahan, P.J., Pleil, J.K., and Evans, G.E., "Method Development and Field Measurements for
Polar Volatile Organic Compounds in Ambient Air," Environ. Sci. Technol., Vol. 27, 1146-1153, 1993.
January 1999        Compendium of Methods for Toxic Organic Air Pollutants           Page 15-31

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Method TO-15	VOCs

7.  McClenny, W.A., Oliver, K.D. and Daughtrey, E.H.., Jr. "Dry Purging of Solid Adsorbent Traps to Remove
Water Vapor Before Thermal Desorption of Trace Organic Gases," J. Air and Waste Manag. Assoc., Vol.
45, 792-800, June 1995.

8.  Whitaker, D.A., Fortmann, R.C. and Lindstrom, A.B. "Development and Testing of a Whole Air Sampler for
Measurement of Personal Exposures to Volatile  Organic Compounds," Journal of Exposure Analysis and
Environmental Epidemiology, Vol. 5, No. 1, 89-100, January  1995.

9.  Pleil, J.D. and Lindstrom, A.B., "Collection  of a Single Alveolar Exhaled Breath for Volatile Organic
Compound Analysis" American Journal of Industrial Medicine,Vol. 28, 109-121, 1995.

10. Pleil, J.D. and McClenny, W.A., "Spatially Resolved Monitoring for Volatile Organic Compounds Using
Remote Sector Sampling," Atmos. Environ., Vol.  27A, No. 5, 739-747, August 1993.

11. Holdren, M.W., et al, Unpublished Final Report, EPA Contract 68-DO-0007, Battelle, Columbus, OH.
Available from J.D. Pleil, MD-44, U. S. Environmental Protection Agency, Research Triangle Park, NC, 27711,
919-541-4680.

12.  Morris, C.M., Burkley, R.E. and Bumgarner, J.E., "Preparation of Multicomponent Volatile Organic
Standards Using Dilution Bottles," Anal. Letts., Vol. 16 (A20), 1585-1593, 1983.

13. Pollack, A.J., Holdren, M.W., "Multi-Adsorbent Preconcentration and Gas Chromatographic Analysis of
Air Toxics With an Automated Collection/Analytical System," in the Proceedings of the 1990 EPA/A&WMA
International Symposium of Measurement of Toxic and Related Air Pollutants, U. S. Environmental Protection
Agency, Research Triangle Park, NC, EPA/600/9-90-026, May 1990.

14. Stephenson, J.H.M., Allen, F., Slagle, T., "Analysis of Volatile Organics in Air via Water Methods" in
Proceedings of the 1990 EPA/A&WMA International Symposium on Measurement of Toxic and Related Air
Pollutants, U. S.  Environmental Protection Agency, Research Triangle Park, NC, EPA  600/9-90-026, May 1990.

15. Oliver, K.  D., Adams, J. R, Davehtrey, E. H., Jr., McClenny, W. A., Young, M. J., and Parade, M.  A.,
"Techniques for Monitoring Toxices VOCs in Air:  Sorbent Preconcentration Closed-Cycle Cooler Cryofocusing,
and GC/MS Analysis," Environ. Sci. Technol.,Vol. 30,  1938-1945, 1996.
Page 15-32           Compendium of Methods for Toxic Organic Air Pollutants        January 1999

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VOCs
                                                        Method TO-15
                                      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 93065
(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
                            VanNuys, 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]
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-33

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Method TO-15	VOCs

                                         APPENDIX B.

                    COMMENT ON 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  0.05mm 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.
Page 15-34           Compendium of Methods for Toxic Organic Air Pollutants        January 1999

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VOCs	Method TO-15

                                     APPENDIX C.

         LISTING OF COMMERCIAL MANUFACTURERS AND RE-SUPPLIERS OF
                          SPECIALLY-PREPARED CANISTERS

BRC/Rasmussen
17010NW 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
VanNuys, CA 91406
(818)787-7380
January 1999       Compendium of Methods for Toxic Organic Air Pollutants          Page 15-35

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Method TO-15	VOCs

                                     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.
299 ICorvin 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

Tracer,  Inc.
6500 Tracer 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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i
 s
TABLE 1. VOLATILE ORGANIC COMPOUNDS ON

   MEMBERSHIP IN COMPENDIUM METHOD TO
THE TITLE III CLEAN AIR AMENDMENT LIST-

MA LIST AND THE SOW-CLP LIST OF VOCs
Compound
Methyl chloride (chloromethane); CH3C1
Carbonyl sulfide; COS
Vinyl chloride (chloroethene); C2H3C1
Diazomethane; CH2N2
Formaldehyde; CH2O
1,3-Butadiene; C4H6
Methyl bromide (bromomethane); CH3Br
Phosgene; CC12O
Vinyl bromide (bromoethene); C2H3Br
Ethylene oxide; C2H4O
Ethyl chloride (chloroethane); C2H5C1
Acetaldehyde (ethanal); C2H4O
Vinylidene chloride (1,1-dichloroethylene); C2H2C12
Propylene oxide; C3H6O
Methyl iodide (iodomethane); CHS I
Methylene chloride; CH2C12
Methyl isocyanate; C2H3NO
Allyl chloride (3-chloropropene); C3H5C1
Carbon disulfide; CS2
Methyl tert-butyl ether; C5H12O
Propionaldehyde; C2H5CHO
Ethylidene dichloride (1,1-dichloroethane); C2H4C12
CAS No.
74-87-3
463-58-1
75-01-4
334-88-3
50-00-0
106-99-0
74-83-9
75-44-5
593-60-2
75-21-8
75-00-3
75-07-0
75-35-4
75-56-9
74-88-4
75-09-2
624-83-9
107-05-1
75-15-0
1634-04-4
123-38-6
75-34-3
BP(°C)
-23.7
-50.0
-14.0
-23.0
-19.5
-4.5
3.6
8.2
15.8
10.7
12.5
21.0
31.7
34.2
42.4
40.0
59.6
44.5
46.5
55.2
49.0
57.0
v.p.
(mmHg)1
3.8x10
3.7x10
3.2x10
2.8x10
2.7x10
2.0x10
1.8x10
1.2x10
1.1x10
1.1x10
1.0x10
952
500
445
400
349
348
340
260
249
235
230
MW1
50.5
60.1
62.5
42.1
30
54
94.9
99
107
44
64.5
44
97
58
141.9
84.9
57.1
76.5
76
86
58.1
99
TO-14A
X

X



X



X

X


X

X



X
CLP-SOW
X

X


X
X



X

X


X

X




O
n
                                                                                                       a-
                                                                                                       o
                                                                                                       Q.

                                                                                                       H
                                                                                                       in

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                                                           TABLE 1. (continued)
oo
i
 s
c_
88

e
ss
Compound
Chloroprene (2-chloro-l,3-butadiene); C4H5C1
Chloromethyl methyl ether; C2H5C1O
Acrolein (2-propenal); C3H4O
1,2-Epoxybutane (1,2-butylene oxide); C4H8O
Chloroform; CHC13
Ethyleneimine (aziridine); C2H5N
U-Dimethylhydrazine; C2H8N2
Hexane; C6H14
1 ,2-Propyleneimine (2-methylaziridine); C3H7N
Acrylonitrile (2-propenenitrile); C3H3N
Methyl chloroform (1,1,1-trichloroethane); C2H3C13
Methanol; CH4O
Carbon tetrachloride; CC14
Vinyl acetate; C4H6O2
Methyl ethyl ketone (2-butanone); C4H8O
Benzene; C6H6
Acetonitrile (cyanomethane); C2H3N
Ethylene dichloride (1,2-dichloroethane); C2H4C12
Triethylamine; C6H15N
Methylhydrazine; CH6N2
Propylene dichloride (1,2-dichloropropane); C3H6C12
2,2,4-Trimethyl pentane C8H18
1,4-Dioxane (1,4-Diethylene oxide); C4H8O2
Bis(chloromethyl) ether; C2H4C12O
Ethyl acrylate; C5H8O2
Methyl methacrylate; C5H8O2
CAS No.
126-99-8
107-30-2
107-02-8
106-88-7
67-66-3
151-56-4
57-14-7
110-54-3
75-55-8
107-13-1
71-55-6
67-56-1
56-23-5
108-05-4
78-93-3
71-43-2
75-05-8
107-06-2
121-44-8
60-34-4
78-87-5
540-84-1
123-91-1
542-88-1
140-88-5
80-62-6
BP(°C)
59.4
59.0
52.5
63.0
61.2
56
63
69.0
66.0
77.3
74.1
65.0
76.7
72 2
79.6
80.1
82
83.5
89.5
87.8
97.0
99.2
101
104
100
101
v.p.
(mmHg)1
226
224
220
163
160
160.0
157.0
120
112
100
100
92.0
90.0
83.0
77.5
76.0
74.0
61.5
54.0
49.6
42.0
40.6
37.0
30.0
29.3
28.0
MW1
88.5
80.5
56
72
119
43
60.0
86.2
57.1
53
133.4
32
153.8
86
72
78
41.0
99
101.2
46.1
113
114
88
115
100
100.1
TO-14A




X


X

X
X

X


X

X


X





CLP-SOW


X

X





X
X
X
X
X
X
X
X


X





                                                                                                                                      o
                                                                                                                                      o.

                                                                                                                                      H
                                                                                                                                      O
                                                                                                                                      n

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88

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TABLE 1.  (continued)
i
 s
Compound
Methyl methacrylate; C5H8O2
1,3-Dichloropropene; C3H4C12 (cis)
Toluene; C7H8
Trichloroethylene; C2HC13
1,1,2-Trichloroethane; C2H3C13
Tetrachloroethylene; C2C14
Epichlorohydrin (l-chloro-2,3-epoxy propane); C3H5C1O
Ethylene dibromide (1,2-dibromoethane); C2H4Br2
N-Nitroso-N-methylurea; C2H5N3O2
2-Nitropropane; C3H7NO2
Chlorobenzene; C6H5C1
Ethylbenzene; C8H10
Xylenes (isomer & mixtures); C8H10
Styrene; C8H8
p-Xylene;C8H10
m-Xylene;C8H10
Methyl isobutyl ketone (hexone); C6H12O
Bromoform (tribromomethane); CHBr3
l,l,2,2-Tetrachloroethane;C2H2C14
o-Xylene;C8H10
Dimethylcarbamyl chloride; C3H6C1NO
N-Nitrosodimethylamine; C2H6N2O
Beta-Propiolactone; C3H4O2
Cumene (isopropylbenzene); C9H12
CAS No.
80-62-101
542-75-6
108-88-3
79-01-6
79-00-5
127-18-4
106-89-8
106-93-4
684-93-5
79-46-9
108-90-7
100-41-4
1330-20-7
100-42-5
106-42-3
108-38-3
108-10-1
75-25-2
79-34-5
95-47-6
79-44-7
62-75-9
57-57-8
98-82-8
BP(°C)
101
112
111
87.0
114
121
117
132
124
120
132
136
142
145
138
139
117
149
146
144
166
152
Decomposes at
162
153
v.p.
(mmgHg;
28.0
27.8
22.0
20.0
19.0
14.0
12.0
11.0
10.0
10.0
8.8
7.0
6.7
6.6
6.5
6.0
6.0
5.6
5.0
5.0
4.9
3.7
3.4
3.2
MW1
100.1
111
92
131.4
133.4
165.8
92.5
187.9
103
89
112.6
106
106.2
104
106.2
106.2
100.2
252.8
167.9
106.2
107.6
74
72
120
TO-14A

X
X
X
X
X

X


X
X
X
X
X
X


X
X




CLP- SOW

X
X
X
X
X

X


X
X
X
X
X
X


X
X




O
n
                                                                                                                                      a-
                                                                                                                                      o
                                                                                                                                      Q.

                                                                                                                                      H

-------
                                                           TABLE 1. (continued)
4-
O
i
 s
c_
88

e
ss
Compound
Cumene (isopropylbenzene); C9H12
Acrylic acid; C3H4O2
N,N-Dimethylformamide; C3H7NO
1,3-Propane sultone; C3H6O3S
Acetophenone; C8H8O
Dimethyl sulfate; C2H6O4S
Benzyl chloride (a-chlorotoluene); C7H7C1
1 ,2-Dibromo-3-chloropropane; C3H5Br2Cl
Bis(2-Chloroethyl)ether; C4H8C12O
Chloroacetic acid; C2H3C1O2
Aniline (aminobenzene); C6H7N
1,4-Dichlorobenzene (p-); C6H4C12
Ethyl carbamate (urethane); C3H7NO2
Acrylamide; C3H5NO
N,N-Dimethylaniline; C8H11N
Hexachloroethane; C2C16
Hexachlorobutadiene; C4C16
Isophorone; C9H14O
N-Nitrosomorpholine; C4H8N2O2
Styrene oxide; C8H8O
Diethyl sulfate; C4H10O4S
Cresylic acid (cresol isomer mixture);C7H8O
o-Cresol; C7H8O
Catechol (o-hydroxyphenol); C6H6O2
Phenol; C6H6O
CAS No.
98-82-8
79-10-7
68-12-2
1120-71-4
98-86-2
77-78-1
100-44-7
96-12-8
111-44-4
79-11-8
62-53-3
106-46-7
51-79-6
79-06-1
121-69-7
67-72-1
87-68-3
78-59-1
59-89-2
96-09-3
64-67-5
1319-77-3
95-48-7
120-80-9
108-95-2
BP(°C)
153
141
153
180/3 Omm
202
188
179
196
178
189
184
173
183
125/25 mm
192
Sublimes at 186
215
215
225
194
208
202
191
240
182
v.p.
(mmHg)1
3.2
3.2
2.7
2.0
1.0
1.0
1.0
0.80
0.71
0.69
0.67
0.60
0.54
0.53
0.50
0.40
0.40
0.38
0.32
0.30
0.29
0.26
0.24
0.22
0.20
MW1
120
72
73
122.1
120
126.1
126.6
236.4
143
94.5
93
147
89
71
121
236.7
260.8
138.2
116.1
120.2
154
108
108
110
94
TO-14A






X




X




X








CLP-SOW






X




X




X








                                                                                                                                      o
                                                                                                                                      o.

                                                                                                                                      H
                                                                                                                                      O
                                                                                                                                      n

-------
c_
88
e
ss
o
n
                                                                      TABLE 1. (continued)
Compound
Catechol (o-hydroxyphenol); C6H6O2
Phenol; C6H6O
1,2,4-Trichlorobenzene; C6H3C13
nitrobenzene- C6H5NO7.
CAS No.
120-80-9
108-95-2
120-82-1
QS-QS-^
BP (°C)
240
182
213
711
v.p.
(mmHg)1
0.22
0.20
0.18
n is
MW1
110
94
181.5
19T
TO-14A


X

CLP-SOW


X

i
  s
             'Vapor 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.
•8
a-
o
Q.
H
O

-------
Method TO-15
                                                        VOCs
        TABLE 2. CHARACTERISTIC MASSES (M/Z) USED FOR QUANTIFYING
             THE TITLE III CLEAN AIR ACT AMENDMENT COMPOUNDS
Compound
Methyl chloride (chloromethane); CH3C1
Carbonyl sulfide; COS
Vinyl chloride (chloroethene); C2H3C1
Diazomethane; CH2N2
Formaldehyde; CH2O
1,3-Butadiene; C4H6
Methyl bromide (bromomethane); CH3Br
Phosgene; CC12O
Vinyl bromide (bromoethene); C2H3Br
Ethylene oxide; C2H4O
Ethyl chloride (chloroethane); C2H5C1
Acetaldehyde (ethanal); C2H4O
Vinylidene chloride (1,1-dichloroethylene); C2H2C12
Propylene oxide; C3H6O
Methyl iodide (iodomethane); CH3I
Methylene chloride; CH2C12
Methyl isocyanate; C2H3NO
Allyl chloride (3-chloropropene); C3H5C1
Carbon disulfide; CS2
Methyl tert-butyl ether; C5H12O
Propionaldehyde; C2H5CHO
Ethylidene dichloride (1,1-dichloroethane); C2H4C12
Chloroprene (2-chloro-l,3-butadiene); C4H5C1
Chloromethyl methyl ether; C2H5C1O
Acrolein (2-propenal); C3H4O
1,2-Epoxybutane (1,2-butylene oxide); C4H8O
Chloroform; CHC13
Ethyleneimine (aziridine); C2H5N
1,1-Dimethylhydrazine; C2H8N2
Hexane; C6H14
1,2-Propyleneimine (2-methylazindine); C3H7N
Acrylonitrile (2-propenenitrile); C3H3N
Methyl chloroform (1,1,1 trichloroethane); C2H3C13
Methanol; CH4O
Carbon tetrachloride; CC14
Vinyl acetate; C4H6O2
Methyl ethyl ketone (2-butanone); C4H8O
CAS No.
74-87-3
463-S8-1
7S-01-4
334-88-3
50-00-0
106-99-0
74-83-9
75-44-5
593-60-2
75-21-8
75-00-3
75-07-0
75-35-4
75-56-9
74-88-4
75-09-2
624-83-9
107-05-1
75-15-0
1634-04-4
123-38-6
75-34-3
126-99-8
107-30-2
107-02-8
106-88-7
67-66-3
151-56-4
57-14-7
110-54-3
75-55-8
107-13-1
71-55-6
67-56-1
56-23-5
108-05-4
78-93-3
Primary Ion
50
60
62
42
29
39
94
63
106
29
64
44
61
58
142
49
57
76
76
73
58
63
88
45
56
42
83
42
60
57
56
53
97
31
117
43
43
Secondary Ion
52
62
64
41
30
54
96
65
108
44
66
29,43
96
57
127
84,86
56
41,78
44,78
41,53
29,57
65,27
53,90
29,49
55
41,72
85,47
43
45,59
41,43
57,42
52
99,61
29
119
86
72
Page 15-42
Compendium of Methods for Toxic Organic Air Pollutants
January 1999

-------
VOCs
                                                      Method TO-15
                                 TABLE 2. (continued)
Compound
Benzene; C6H6
Acetonitrile (cyanomethane); C2H3N
Ethylene dichloride (1,2-dichloroethane); C2H4C12
Triethylamine; C6H15N
Methylhydrazine; CH6N2
Propylene dichloride (1,2-dichloropropane); C3H6C12
2,2,4- Trimethyl pentane; C8H18
1,4-Dioxane (1,4 Diethylene oxide); C4H8O2
Bis(chloromethyl) ether; C2H4C12O
Ethyl acrylate; C5H8O2
Methyl methacrylate; C5H8O2
1,3-Dichloropropene; C3H4C12 (cis)
Toluene; C7H8
Trichloethylene; C2HC13
1,1,2-Trichloroethane; C2H3C13
Tetrachloroethylene; C2C14
Epichlorohydrin (l-chloro-2,3-epoxy propane); C3H5C1O
Ethylene dibromide (1,2-dibromoethane); C2H4Br2
N-Nitrso-N-methylurea; C2H5N3O2
2-Nitropropane; C3H7NO2
Chlorobenzene; C6H5C1
Ethylbenzene; C8H10
Xylenes (isomer & mixtures); C8H10
Styrene; C8H8
p-Xylene; C8H10
m-Xylene; C8H10
Methyl isobutyl ketone (hexone); C6H12O
Bromoform (tribromomethane); CHBrS
l,l,2,2-Tetrachloroethane;C2H2C14
o-Xylene; C8H10
Dimethylcarbamyl chloride; C3H6C1NO
N-Nitrosodimethylamine; C2H6N2O
Beta-Propiolactone; C3H4O2
Cumene (isopropylbenzene); C9H12
Acrylic acid; C3H4O2
N,N-Dimethylformamide; C3H7NO
1,3-Propane sultone; C3H6O3S
CAS No.
71-43-2
75-05-8
107-06-2
121-44-8
60-34-4
78-87-5
540-84-1
123-91-1
542-88-1
140-88-5
80-62-6
542-75-6
108-88-3
79-01-6
79-00-5
127-18-4
106-89-8
106-93-4
684-93-5
79-46-9
108-90-7
100-41-4
1330-20-7
100-42-5
106-42-3
108-38-3
108-10-1
75-25-2
79-34-5
95-47-6
79-44-7
62-75-9
57-57-8
98-82-8
79-10-7
68-12-2
1120-71-4
Primary Ion
78
41
62
86
46
63
57
88
79
55
41
75
91
130
97
166
57
107
60
43
112
91
91
104
91
91
43
173
83
91
72
74
42
105
72
73
58
Secondary Ion
77,50
40
64,27
58,101
31,45
41,62
41,56
58
49,81
73
69, 100
39,77
92
132,95
83,61
164,131
49,62
109
44, 103
41
77,114
106
106
78, 103
106
106
58, 100
171,175
85
106
107
42
43
120
45,55
42,44
65, 122
                                 TABLE 2. (continued)
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-43

-------
Method TO-15
                                                               VOCs
Compound
Acetophenone; C8H8O
Dimethyl sulfate; C2H6O4S
Benzyl chloride (a-chlorotoluene); C7H7C1
1 ,2-Dibromo-3-chloropropane; C3H5Br2Cl
Bis(2-Chloroethyl)ether;C4H8C12O
Chloroacetic acid; C2H3C1O2
Aniline (aminobenzene); C6H7N
1,4-Dichlorobenzene (p-); C6H4C12
Ethyl carbamate (urethane); C3H7NO2
Acrylamide; C3H5NO
N,N-Dimethylaniline; C8H11N
Hexachloroethane; C2C16
Hexachlorobutadiene; C4C16
Isophorone; C9H14O
N-Nitrosomorpholine; C4H8N2O2
Styrene oxide; C8H8O
Diethyl sulfate; C4H10O4S
Cresylic acid (cresol isomer mixture); C7H8O
o-Cresol; C7H8O
Catechol (o-hydroxyphenol); C6H6O2
Phenol; C6H6O
1,2,4-Trichlorobenzene; C6H3C13
Nitrobenzene; C6H5NO2
CAS No.
98-86-2
77-78-1
100-44-7
96-12-8
111-44-4
79-11-8
62-53-3
106-46-7
51-79-6
79-06-1
121-69-7
67-72-1
87-68-3
78-59-1
59-89-2
96-09-3
64-67-5
1319-77-3
95-48-7
120-80-9
108-95-2
120-82-1
98-95-3
Primary Ion
105
95
91
57
93
50
93
146
31
44
120
201
225
82
56
91
45

108
110
94
180
77
Secondary Ion
77,120
66,96
126
155,157
63,95
45,60
66
148,111
44,62
55,71
77, 121
199,203
227, 223
138
86,116
120
59, 139

107
64
66
182, 184
51,123
Page 15-44
Compendium of Methods for Toxic Organic Air Pollutants
January 1999

-------
VOCs
                                                       Method TO-15
                       TABLE 3. REQUIRED BFB KEY IONS AND
                              TON ABUNDANCE CRITERIA
Mass
50
75
95
96
173
174
175
176
177
Ion Abundance Criteria1
8.0 to 40.0 Percent of m/e 95
30.0 to 66.0 Percent of m/e 95
Base Peak, 100 Percent Relative Abundance
5.0 to 9.0 Percent of m/e 95 (See note)
Less than 2.0 Percent of m/e 174
50.0 to 120.0 Percent of m/e 95
4.0 to 9.0 Percent of m/e 174
93.0 to 101.0 Percent of m/e 174
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.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-45

-------
Method TO-15
                                                                        VOCs
                        TABLE 4. METHOD DETECTION LIMITS fMDLV
TO-14A List
Benzene
Benzyl Chloride
Carbon tetrachloride
Chlorobenzene
Chloroform
1 ,3-Dichlorobenzene
1 ,2-Dibromoethane
1 ,4-Dichlorobenzene
1 ,2-Dichlorobenzene
1 , 1 -Dichloroethane
1,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethene
Methylene chloride
1 ,2-Dichloropropane
cis- 1 ,3-Dichloropropene
trans- 1 ,3-Dichloropropene
Ethylbenzene
Chloroethane
Trichlorofluoromethane
1 , 1 ,2-Trichloro- 1 ,2,2-trifluoroethane
1 ,2-Dichloro- 1 , 1 ,2,2-tetrafluoroethane
Dichlorodifluoromethane
Hexachlorobutadiene
Bromomethane
Chloromethane
Styrene
1,1,2,2-Tetrachloroethane
Tetrachloroethene
Toluene
1 ,2,4-Trichlorobenzene
UJ-Trichloroethane
1,1,2-Trichloroethane
Trichloroethene
1 ,2,4-Trimethylbenzene
1,3,5-Trimethylbenzene
Vinyl Chloride
m,p-Xvlene
o-Xylene
Lab #1, SCAN
0.34
__
0.42
0.34
0.25
0.36
__
0.70
0.44
0.27
0.24
__
__
1.38
0.21
0.36
0.22
0.27
0.19
__

__
__
__
0.53
0.40
1.64
0.28
0.75
0.99
__
0.62
0.50
0.45
__
	
0.33
0.76
0.57
Lab #2, SIM
0.29
__
0.15
0.02
0.07
0.07
0.05
0.12
__
0.05
__
0.22
0.06
0.84
__
__
__
0.05
__
__
__
__
__
__
__
__
0.06
0.09
0.10
0.20
__
0.21
__
0.07
__
	
0.48
0.08
0.28
                   '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.
Page 15-46
Compendium of Methods for Toxic Organic Air Pollutants
January 1999

-------
VOCs
                                                            Method TO-15
           TABLE 5. SUMMARY OF EPA DATA ON REPLICATE PRECISION (RP)
                            FROM EPA NETWORK OPERATIONS1
Monitoring Compound
Identification
Dichlorodifluoromethane
Methylene chloride
1 ,2-Dichloroethane
1,1,1 -Trichloroethane
Benzene
Trichloroethene
Toluene
Tetrachloroethene
Chlorobenzene
Ethylbenzene
m-Xylene
Styrene
o-Xylene
p-Xylene
1 , 3 -Dichlorobenzene
1 ,4-Dichlorobenzene
EPA's Urban Air Toxics Monitoring
Program (UATMP)
%RP
__
16.3
36.2
14.1
12.3
12.8
14.7
36.2
20.3
14.6
14.7
22.8
49.1
14.7
#

07
31
44
56
08
76
12
21
32
75
592
06
14
ppbv
__
4.3
1.6
1.0
1.6
1.3
3.1
0.8
0.9
0.7
4.0
1.1
0.6
6.5
EPA's Toxics Air Monitoring Stations
(TAMS)
%RP
13.9
19.4
--
10.6
4.4
-_
3.4
--
-_
5.4
5.3
8.7
6.0
--
#
47
47
--
47
47
-_
47
--
-_
47
47
47
47
--
ppbv
0.9
0.6
--
2.0
1.5
-_
3.1
--
-_
0.5
1.5
0.22
0.5
--
'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
Vinyl chloride
Bromomethane
Trichlorofluoromethane
Methylene chloride
Chloroform
1 ,2-Dichloroethane
1,1,1 -Trichloroethane
Benzene
Carbon tetrachloride
1 ,2-Dichloropropane
Trichloroethene
Toluene
Tetrachloroethene
Chlorobenzene
Ethylbenzene
o-Xylene
FY-88 TAMS AA(%), N=30
4.6
-_
6.4
8.6
6.8
18.6
10.3
12.4
8.8
8.3
6.2
10.5
12.4
16.2
FY-88 UATMP AA(%), N=3
17.9
6.4
—
31.4
4.2
11.4
11.3
10.1
9.4
6.2
5.2
12.5
--
11.7
12.4
21.2
'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.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-47

-------
Method TO-15
                                                                       VOCs
                                                  To AC
       Inlet
                                         Type Pump
                                       for Pressurized  I  I
                                                    To AC
          Figure 1.  Sampler configuration for subatmospheric pressure or pressurized canister sampling.
Page 15-48
Compendium of Methods for Toxic Organic Air Pollutants
January 1999

-------
VOCs
                                                                         Method TO-15
TIMER ".WVN^,
SWITCH f Ci \
O 1 || 1
-o*"* 40/rfd. 450 V DC
AC °~~l RZ 100I<
^
V
?40;rfd. 450 V DC
RED
Di
BLACK
igd
D2
WHITE

IIAGNELATCH
SOLENOID
VALVE
               Copocitor Ci  and Cz - 40 ut. 450 VDC (Sprogue Atom  TVA 1712 or equivonent)
               Rewler RI and R2 - 0.5 -all. SK tolerann
               Diode Di and Dt - 1000 PRV. 2.5 A (RCA. SK 3081 or aqijvolenl)
            (a). Simple Circuit  for Operating  Mognelotch Valve
Di
_ ^
WITCH /
-0^




" l
1 T '


s^\
r PUMPJ




AC
BRIDGE
RECTIFIER
AC


12.7K 2.7K / ^
•^ 1 ^~~^\
. Ci () "EIAY
vlx 200 ui nr •«*
- -|- 200 volt | ^

RED

BLACK
1 	



"mn C2
I/' WHITE
IV,



UACNELATCH
SOLENOID
VALVE




COMPONENTS ^"vo,,
               Bridge Rectifier - 200 PRV. 1.5 A (RCA SK 3105 or equivalent)
               Diode Di and Oi - 1000 PRV. 2.5 A (RCA. SK 3081 or equivalent)

               Capacitor Ci - 200 ut. 250 VDC (Sprogue Atom TVA 1528 or equivalent)

               Capacitor Ci - 20 uf. 400 VDC Nan-Polarized (Sprogue Atom TVAN 1652 or equivalent)

               Relay - 10.000 ohm  coil. 3.5 mo (AUF Potter and  BrumKeM. KCP 5. or equivalent)
               Roister RI and RZ - 0.5 wall, yt tolerance


            (b). Improved  Circuit  Designed  to  Handle  Power  Interruptions
             Figure 2.  Electrical pulse circuits for driving Skinner magnelatch solenoid valve with
                                                mechanical timer.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-49

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Method TO-15
                                                                       VOCs
                                                                             )    ]    I Auxilliory
                                                                                     Vacuum
                                                                                      Pump
                                                           To AC
                 Figure 3.  Alternative sampler configuration for pressurized canister sampling.
Page 15-50
Compendium of Methods for Toxic Organic Air Pollutants         January 1999

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VOCs
                                           Method TO-15
       STAGE 1; SAMPLE TRANSFER TO THE PRECONCENTRATION TRAP
            1
              rs
                CANISTER
     SORBENTTUBE
   T
±
                             ADSORBENTTRAP
AT NEAR AMBIENT
 TEMPERATURE
         SAMPLER INLET
         ^
        AIR SAMPLE IN
                      SAMPLE GAS
                        FLOW     CARRIER
                                  GAS IN
                         STAGE 2: DRY PURGING
                DRYHEUUM  ^ADSORBENT TRAP

                PURGE GAS
                             AT NEAR AMBIENT
                              TEMPERATURE
                       r
                                       PURGE GAS
                                      PLUS WATER
                                                   CARRIER
                                                    GAS IN
  STAGE 3: TRAP DESORPTION - ANALYTE TRANSFER TO GC COLUMN
                        CARRIER GAS IN'
                            ADSORBENTTRAP
                       J
                                 (HOT)
               Figure 4. Illustration of three stages of dry purging of adsorbent trap.
January 1999      Compendium of Methods for Toxic Organic Air Pollutants
                                              Page 15-51

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i
 s
e
150
140.
«, 130
x 120
w
Z 110
O
0 100(
tt 90
CO 80
1 ?°
tt 60
1 50
O
Q 40
1 30
20
10
0

I I I I I I I I I I
TEMPERATURE, °C -
1 B45
• 55
A 65 -
i
_ —

i
	
- •
A A
h A • "
i i i i i i i i t i











0 100 200 300 400 500 600 700 800 900 1000 1100
PURGE VOLUME, ml
                                                                                                                                                      O
                                                                                                                                                      O.

                                                                                                                                                      H
                                           Figure 5. Residual water vapor on VOC concentrator vs. dry He purge volume.
O
n

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VOCs
                                                              Method TO-15
               GC
             Column
             Effluent
       Ion
     Source/
     Filament
                      Figure 6.  Simplified diagram of a quadrupole mass spectrometer.
                                          Filament
                           Ring|\
                         Electrode \
        GC —
      Column
      Effluent
                                                             End Cap
                                                            Ring
                                                          Electrode
                                        End Cap
                                                        Supplementary
                                                          rf Voltage
                                           Y   1   Electron Multiplier
                       Figure 7.  Simplified diagram of an ion trap mass spectrometer.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-53

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(71
(71
4-
                                                                                     (a)  Real  Time
                                                                                   GC-FID-ECD-PID
                                                                                       or  GC-MS
                                                                                                                        o
                                                                                                                        o.
                                                                                                                        H
                                                                                                                        9
                                                                                                                        h^
                                                                                                                        (71
               Calibration Cos
                  Cylinder
i
 s
   Mass Flow
   Controller
(0-50 mL/min)
                                                                     Internal
                                                                     Baffles
Teflon
Filter
                  Zero Air
                  Cylinder
   Mass Flow
   Controller
 (0-50  L/min)
                                Vacuum/Pressure
                                     Cauge
                                                                  Heated  Calibration Manifold
e
                                                                                                     Teflon
                                                                                                     Filter
                                                                                                        Pump
                                                                                                                                              Shut Off
                                                                                                                                                Valve
                                                                                                        Flow
                                                                                                      Control
                                                                                                       Valve
                                                                          (b)  Evacuated or Pressurized
                                                                           Canister Sampling System
                                                                500  ml
                                                             Round-Bottom
                                                                 Flask
                                                                                                                                (c) Canister Transfer
                                                                                                                                     Standard
                                                 Humidifier
                                                   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.
                                                                                                                        O
                                                                                                                        n

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VOCs
                                                        Method TO-15
                             COMPENDIUM METHOD TO-15
                    CANISTER SAMPLING FIELD TEST DATA SHEET
A.GENERAL INFORMATION
    SITE LOCATION:
    SITE ADDRESS:
                            SHIPPING DATE: 	
                            CANISTER SERIAL NO.:
                            SAMPLER ID: 	
    SAMPLING DATE:
                               OPERATOR:
                                               CANISTER LEAK
                                                  CHECK DATE:
B.  SAMPLING INFORMATION
                              TEMPERATURE
                                                     PRESSURE

START
STOP

START
STOP
INTERIOR


AMBIENT


MAXIMUM


MINIMUM





CANISTER PRESSURE


SAMPLING TIMES FLOW RATES
LOCAL TIME


ELAPSED TIME
METER READING





MANIFOLD
FLOW RATE


CANISTER
FLOW RATE


FLOW
CONTROLLER
READOUT


SAMPLING SYSTEM CERTIFICATION DATE:
QUARTERLY RECERTIFICATION DATE: 	
C.  LABORATORY INFORMATION
   DATA RECEIVED:
   RECEIVED BY:
   INITIAL PRESSURE: 	
   FINAL PRESSURE:  	
   DILUTION FACTOR: 	
   ANALYSIS
    GC-FID-ECD DATE: _
    GC-MSD-SCAN DATE:
    GC-MSD-SIMDATE: _
   RESULTS*: 	
    GC-FID-ECD: _
    GC-MSD-SCAN:
    GC-MSD-SIM:
                                               SIGNATURE/TITLE
                     Figure 9. Canister sampling field test data sheet (FTDS).
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-55

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Method TO-15
                                                                             VOCs
                                                                                                 Pressure
                                                                                                Regulator
                                         Exhaust
                                 Vacuum  Pump
                                 Shut  Off Valve
         Exhaust ^	1 Vacuum
                        Pump
                      XX
                           Vent
                           Valve
                                                             Vent Shut
                                                             Off Valve
                                          Cryogenic
                                         Trap Cooler
                                        (Liquid Argon)
                                          Vacuum
                                           Gauge
                                          Shut Off
                                           Valve
         Exhaust
                                                                             Cryogenic
                                                                            Trap Cooler
                                                                           (Liquid Argon)
                                                                          Humidifier
                                                                             Zero
                                                                           Shut Off
                                                                             Valve
                                                    Flow
                                                   Control
                                                   Valve
                                                                            Manifold
                                                                            Optional
                                                                           Isothermal
                                                                              Oven
                                        Figure 10. Canister cleaning system.
Page 15-56
Compendium of Methods for Toxic Organic Air Pollutants
January 1999

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VOCs
                                                                        Method TO-15
                     Vent
                                                                                             Carrier
                                                                                              Gas
                Water Management
                  System and
               Main Preconcentrator

                  Optional
                  Pressure
                  Gauge
-\
\&J
(

                                                         Cryogenic
                                                       Trapping Unit
                                                                     6-Port
                                                                 Chrotnotographic
                                                                     Valve
                                                   Flame lonization   I
                                                    Detector (FID)    J
                                                                                       OV-1 Capillary Column
                                                                                         (0.32 mm x 50 m)
                                                              Low Dead-Volume
                                                               Tee (Optional)
                                                           i
                                                          rh
                                                          I   I Flow Restrictor
                                                          I   '   (Optional)
                                                                              Mass Spectrometer
                                                                             in SCAN or SIM Mode
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.]
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-57

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Method TO-15
                                                                    VOCs
          TIME
      (o).  Certified Sampler
      (b).  Contaminated  Sampler
                  Figure 12. Example of humid zero air test results for a clean sample canister
                               (a) and a contaminated sample canister (b).
Page 15-58
Compendium of Methods for Toxic Organic Air Pollutants        January 1999

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VOCs
                                                                          Method TO-15
                                         PRECONCENTRATOR
                                              (-160° C)
                                                                  0.25 cc
                                                                  LOOP
                                            INSULATED INTERNAL STANDARD
                                                VALVE BOX (45 ± 2° C)
           INT. STD.
                         Figure 13. Diagram of design for internal standard addition.
January 1999
                   Compendium of Methods for Toxic Organic Air Pollutants
Page 15-59

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Method TO-15
                                                                    VOCs
                                      3-WAY VALVE
               AIR GAUGE
                                                        FLOWMETER
                                      2-WAY VALVE
                                                                     NITROGEN
                         Figure 14. Water method of standard preparation in canisters.
Page 15-60
Compendium of Methods for Toxic Organic Air Pollutants        January 1999

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VOCs
                                                         Method TO-15
                                          Humidifier
                                                                             Exhaust
          Calibration   Zero Air
         Gas Cylinder  Cylinder
          T = Thermocouple
          F = Zero Dead Vol. Fit.
         FC = Flow Controller
          S = Solenoid Valve
             To
         Auto. Temp.
           Control
                           Figure 15.  Diagram of the GC/MS analytical system.
January 1999
Compendium of Methods for Toxic Organic Air Pollutants
Page 15-61

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i
 s
                       STATUS:

                        TRAP 1: Sampling
                        TRAP 2: Desorbing
                        CLOSED
A
                       MFCF
                           PUMP
                                        MFC
                       SAMPLE PUMP

                       SAMPLE INLET

                       CAL/INT STD
                       PURGE GAS
                       CAL GAS
                         »•
                       INTERNAL STD
                   SV-21
                 f	C*3—<>

                    :4J
                   SV-4B
                  —&3—n
                       PUJGE GA_S	§AM_PLE___PURGE_
                       VENT
HELIUM
                                          SOLID SORBENT CONCENTRATOR
                                                                                                                                    TO GC/
                                                                                                                                  DETECTOR
                                                                            STIRLING CYCLE COOLER
                                                                                                                     o
                                                                                                                     o.
                                                                                                                     H
e
•s
                          16. Saillplc llow diagiaill OI a COiliiliciCially available COiiCciitiatoi sliOWifig tile COilibiiiatiOii OI iliultiSOibciit tube aild COOlci
                                                             (Trap 1 sampling; Trap 2 desorbing).
                                                                                                                     O
                                                                                                                     n

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VOCs                                                                     Method TO-15
January 1999       Compendium of Methods for Toxic Organic Air Pollutants          Page 15-63

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