环境空气 挥发性有机物的测定 美国EPA Method TO-10ar

EPA/625/R-96/010b

Compendium of Methodsfor the Determination of Toxic Organic Compounds

in Ambient Air

Second Edition

Compendium Method TO-10ADetermination Of Pesticides AndPolychlorinated Biphenyls In AmbientAir Using Low Volume PolyurethaneFoam (PUF) Sampling Followed ByGas Chromatographic/Multi-Detector

Detection (GC/MD)

Center for Environmental Research Information

Office of Research and DevelopmentU.S. Environmental Protection Agency

Cincinnati, OH 45268

January 1999

Method TO-10AAcknowledgements

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

John Burckle, U.S. EPA, ORD, Cincinnati, OHJames L. Cheney, Corps of Engineers, Omaha, NBMichael Davis, U.S. EPA, Region 7, KC, KS

Joseph B. Elkins Jr., U.S. EPA, OAQPS, RTP, NCRobert G. Lewis, U.S. EPA, NERL, RTP, NC

Justice A. Manning, U.S. EPA, ORD, Cincinnati, OHWilliam A. McClenny, U.S. EPA, NERL, RTP, NCFrank F. McElroy, U.S. EPA, NERL, RTP, NCHeidi Schultz, ERG, Lexington, MA

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

Method TO-10 was originally published in March of 1989 as one of a series of peer reviewed methods in thesecond supplement to "Compendium of Methods for the Determination of Toxic Organic Compounds inAmbient Air," EPA 600/4-89-018. In an effort to keep these methods consistent with current technology,Method TO-10 has been revised and updated as Method TO-10A in this Compendium to incorporate new orimproved sampling and analytical technologies. In addition, this method incorporates ASTM Method D 4861-94,Standard Practice for Sampling and Analysis of Pesticides and Polychlorinated Biphenyls in Air.This Method is the result of the efforts of many individuals. Gratitude goes to each person involved in thepreparation and review of this methodology.

Author(s)

Robert G. Lewis, U.S. EPA, NERL, RTP, NC

Peer Reviewers William T. "Jerry" Winberry, Jr., EnviroTech Solutions, Cary, NC Irene D. DeGraff, Supelco, Bellefonte, PA Lauren Drees, U.S. EPA, NRMRL, Cincinnati, OH

Finally, recognition is given to Frances Beyer, Lynn Kaufman, Debbie Bond, Cathy Whitaker, and Kathy Johnsonof Midwest Research Institute's Administrative Services staff whose dedication and persistence during thedevelopment 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 orThis 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 orcommercial products does not constitute endorsement or recommendation for use.

ii

METHOD TO-10A

Determination Of Pesticides And Polychlorinated Biphenyls In AmbientAir Using Low Volume Polyurethane Foam (PUF) Sampling Followed By

Gas Chromatographic/Multi-Detector Detection (GC/MD)

TABLE OF CONTENTS

1.Scope.....................................................................2.Summary of Method.........................................................3.Significance................................................................4.

Applicable Documents.......................................................4.1ASTM Standards.......................................................4.2EPA Documents........................................................4.3Other Documents.......................................................5.Definitions.................................................................6.Interferences................................................................7.

Equipment and Materials.....................................................7.1Materials for Sample Collection...........................................7.2Equipment for Analysis..................................................7.3Reagents and Other Materials.............................................8.

Assembly and Calibration of Sampling System....................................8.1Description of Sampling Apparatus........................................8.2Calibration of Sampling System...........................................9.Preparation of PUF Sampling Cartridges.........................................10.Sampling..................................................................11.

Sample Extraction Procedure..................................................11.1Sample Extraction......................................................11.2Sample Cleanup........................................................

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TABLE OF CONTENTS (continued)

12.

Analytical Procedure.........................................................12.1Analysis of Organochlorine Pesticides by Capillary Gas Chromatography with

Electron Capture Detector (GC/ECD).......................................12.2Analysis of Organophosphorus Pesticides by Capillary Gas Chromatography

with Flame Photometric or Nitrogen-Phosphorus Detectors (GC/FPD/NPD)........12.3Analysis of Carbamate and Urea Pesticides by Capillary Gas Chromatography

with Nitrogen-Phosphorus Detector........................................12.4Analysis of Carbamate, Urea, Pyrethroid, and Phenolic Pesticides by High

Performance Liquid Chromatography (HPLC)................................12.5Analysis of Pesticides and PCBs by Gas Chromatography with Mass

Spectrometry Detection (GC/MS)..........................................12.6Sample Concentration...................................................13.

Calculations................................................................13.1Determination of Concentration...........................................14.

Sampling and Retention Efficiencies............................................14.1General...............................................................14.2Determining SE........................................................15.

Performance Criteria and Quality Assurance......................................15.1Standard Operating Procedures (SOPs).....................................15.2Process, Field, and Solvent Blanks.........................................15.3Sampling Efficiency and Spike Recovery....................................15.4Method Precision and Bias...............................................15.5Method Safety.........................................................16.

References.................................................................

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METHOD TO-10A

Determination Of Pesticides And Polychlorinated Biphenyls In AmbientAir Using Low Volume Polyurethane Foam (PUF) Sampling Followed By

Gas Chromatographic/Multi-Detector (GC/MD) Detection

1. Scope

1.1 This document describes a method for sampling and analysis of a variety of common pesticides and forpolychlorinated biphenyls (PCBs) in ambient air. The procedure is based on the adsorption of chemicals fromambient air on polyurethane foam (PUF) or a combination of PUF and granular sorbent using a low volumesampler.

1.2 The low volume PUF sampling procedure is applicable to multicomponent atmospheres containing commonpesticide concentrations from 0.001 to 50 Fg/m3 over 4- to 24-hour sampling periods. The limits of detectionwill depend on the nature of the analyte and the length of the sampling period.

1.3 Specific compounds for which the method has been employed are listed in Table 1. The analyticalmethodology described in Compendium Method TO-10A is currently employed by laboratories throughout theU.S. The sampling methodology has been formulated to meet the needs of common pesticide and PCB samplingin ambient air.

1.4 Compendium Method TO-10 was originally published in 1989. The method was further modified for indoorair application in 1990. In an effort to keep the method consistent with current technology, CompendiumMethod TO-10 has incorporated ASTM Method D4861-94 (1) and is published here as CompendiumMethod TO-10A.

2. Summary of Method

2.1 A low-volume (1 to 5 L/minute) sample is used to collect vapors on a sorbent cartridge containing PUF orPUF in combination with another solid sorbent. Airborne particles may also be collected, but the samplingefficiency is not known (2).

2.2 Pesticides and other chemicals are extracted from the sorbent cartridge with 5 percent diethyl ether in hexaneand determined by gas chromatography coupled with an electron capture detector (ECD), nitrogen-phosphorusdetector (NPD), flame photometric detector (FPD), Hall electrolytic conductivity detector (HECD), or a massspectrometer (MS). For common pesticides, high performance liquid chromatography (HPLC) coupled with anultraviolet (UV) detector or electrochemical detector may be preferable. This method describes the use of anelectron capture detector.

2.3 Interferences resulting from analytes having similar retention times during GC analysis are resolved byimproving the resolution or separation, such as by changing the chromatographic column or operating parameters,or by fractionating the sample by column chromatography.

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Method TO-10APesticides/PCBs

3. Significance

3.1 Pesticide usage and environmental distribution are common to rural and urban areas of the United States.The application of pesticides can cause potential adverse health effects to humans by contaminating soil, water,air, plants, and animal life. However, human exposure to PCBs continues to be a problem because of theirpresence in the environment.

3.2 Many pesticides and PCBs exhibit bioaccumulative, chronic health effects; therefore, monitoring the presenceof these compounds in ambient air is of great importance.

3.3 Use of a portable, low volume PUF sampling system allows the user flexibility in locating the apparatus.The user can place the apparatus in a stationary or mobile location. The portable sampling apparatus may bepositioned in a vertical or horizontal stationary location (if necessary, accompanied with supporting structure).Mobile positioning of the system can be accomplished by attaching the apparatus to a person to test air in theindividual's breathing zone.

3.4 Moreover, this method has been successfully applied to measurement of common pesticides in outdoor air,indoor air and for personal respiratory exposure monitoring (3).

4. Applicable Documents4.1 ASTM Standards

D1356 Definition of Terms Relating to Atmospheric Sampling and Analysis

D4861-94 Standard Practice for Sampling and Analysis of Pesticides and Polychlorinated Biphenylsin Air

E260 Recommended Practice for General Gas Chromatography Procedures E355 Practice for Gas Chromatography Terms and Relationships

D3686 Practice for Sampling Atmospheres to Collect Organic Compound Vapors (Activated CharcoalTube Adsorption Method

D3687 Practice for Analysis of Organic Compound Vapors Collected by the Activated Charcoal TubeAdsorption

D4185 Practice for Measurement of Metals in Workplace Atmosphere by Atomic AbsorptionSpectrophotometry4.2 EPA Documents

Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air: MethodTO-10, Second Supplement, U. S. Environmental Protection Agency, EPA 600/4-89-018, March 1989. Manual of Analytical Methods for Determination of Pesticides in Humans and EnvironmentalStandards, U. S. Environmental Protection Agency, EPA 600/8-80-038, June 1980.

Compendium of Methods for the Determination of Air Pollutants in Indoor Air: Method IP-8, U. S.Environmental Protection Agency, EPA 600/4-90-010, May 1990.

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Pesticides/PCBs4.3 Other Documents

Code of Federal Regulations, Title 40, Part 136, Method 604

Method TO-10A

5. Definitions

should be consistent with ASTM D1356, E260, and E355. All abbreviations and symbols are defined withinthis document at point of use.]

5.1 Sampling efficiency (SE)-ability of the sampling medium to trap analytes of interest. The percentage ofthe analyte of interest collected and retained by the sampling medium when it is introduced as a vapor in air ornitrogen into the air sampler and the sampler is operated under normal conditions for a period of time equal toor greater than that required for the intended use is indicated by %SE.

5.2 Retention efficiency (RE)-ability of sampling medium to retain a compound added (spiked) to it in liquidsolution.

5.3 Static retention efficiency-ability of the sampling medium to retain the solution spike when the samplecartridge is stored under clean, quiescent conditions for the duration of the test period.

5.4 Dynamic retention efficiency (REd)-ability of the sampling medium to retain the solution spike when airor nitrogen is drawn through the sampling cartridge under normal operating conditions for the duration of the testperiod. The dynamic RE is normally equal to or less than the SE.

5.5 Retention time (RT)-time to elute a specific chemical from a chromatographic column, for a specific carriergas flow rate, measured from the time the chemical is injected into the gas stream until it appears at the detector.5.6 Relative retention time (RRT)-a rate of RTs for two chemicals for the same chromatographic column andcarrier gas flow rate, where the denominator represents a reference chemical.

5.7 Surrogate standard-a chemically inert compound (not expected to occur in the environmental sample) thatis added to each sample, blank, and matrix-spiked sample before extraction and analysis. The recovery of thesurrogate standard is used to monitor unusual matrix effects, gross sample processing errors, etc. Surrogaterecovery is evaluated for acceptance by determining whether the measured concentration falls within acceptablelimits.

6. Interferences

6.1 Any gas or liquid chromatographic separation of complex mixtures of organic chemicals is subject to seriousinterference problems due to coelution of two or more compounds. The use of capillary or microbore columnswith superior resolution or two or more columns of different polarity will frequently eliminate these problems.In addition, selectivity may be further enhanced by use of a MS operated in the selected ion monitoring (SIM)mode as the GC detector. In this mode, co-eluting compounds can often be determined.

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6.2 The ECD responds to a wide variety of organic compounds. It is likely that such compounds will beencountered as interferences during GC/ECD analysis. The NPD, FPD, and HECD detectors are element specific,but are still subject to interferences. UV detectors for HPLC are nearly universal, and the electrochemicaldetector may also respond to a variety of chemicals. Mass spectrometric analyses will generally provide positiveidentification of specific compounds.

6.3 PCBs and certain organochlorine pesticides (e.g., chlordane) are complex mixtures of individual compoundswhich can cause difficulty in accurately quantifying a particular formulation in a multiple component mixture.PCBs may interfere with the determination of pesticides.

6.4 Contamination of glassware and sampling apparatus with traces of pesticides or PCBs can be a major sourceof error, particularly at lower analyte concentrations. Careful attention to cleaning and handling procedures isrequired during all steps of sampling and analysis to minimize this source of error.6.5 The general approaches listed below should be followed to minimize interferences.

6.5.1 Polar compounds, including certain pesticides (e.g., organophosphorus and carbamate classes) can beremoved by column chromatography on alumina. Alumina clean-up will permit analysis of most organochlorinepesticides and PCBs (4).

6.5.2 PCBs may be separated from other organochlorine pesticides by column chromatography on silicic acid(5,6).

6.5.3 Many pesticides can be fractionated into groups by column chromatography on Florisil (6).

7. Equipment and Materials7.1 Materials for Sample Collection

7.1.1 Continuous-Flow Sampling Pump (see Figure 1). The pump should provide a constant air flowPark, Bellefonte, PA; SKC, 334 Valley View Road, Eighty Four, PA and other manufacturers.

7.1.2 Sampling Cartridge (see Figure 2). Constructed from a 20-mm (I.D.) x 10-cm borosilicate glass tubedrawn down to a 7-mm (O.D.) open connection for attachment to the pump by way of flexible tubing (seeFigure 1).

7.1.3 Sorbent, Polyurethane Foam (PUF). Cut into a cylinder, 22-mm I.D. and 7.6-cm long, fitted underslight compression inside the cartridge. The PUF should be of the polyether type, (density of 0.0225 g/cm3).This is the type of foam used for furniture upholstery, pillows, and mattresses. The PUF cylinders (plugs) shouldbe slightly larger in diameter than the internal diameter of the cartridge. The PUF sorbent may be cut by one ofthe following means:

With a high-speed cutting tool, such as a motorized cork borer. Distilled water should be used to lubricatethe cutting tool.

With a hot wire cutter. Care should be exercised to prevent thermal degradation of the foam. With scissors, while plugs are compressed between the 22-mm circular templates.Alternatively, pre-extracted PUF plugs and glass cartridges may be obtained commercially.

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Pesticides/PCBsMethod TO-10A

7.1.4 Particle Filter. The collection efficiency of PUF for small-diameter (0.1 to 1 Fm) airborne particlesis only about 20% (7). However, most pesticides and PCBs exist in air under steady-state conditions primarilyas vapors (8). Most particulate-associated pesticides or PCBs, if any, will also tend to be vaporized from filtersafter collection (9). Collocated sampling with and without a quartz-fiber pre-filter has yielded indistinguishableresults for a broad spectrum of pesticides and PCBs found in indoor air (10).

7.1.4.1 An open-face filter may be attached to the sampling cartridge by means of a union for 1-in.(25.4-mm) tubing.

7.1.4.2 A 32-mm diameter quartz microfiber filter (e.g., Palifelex® type 2500 QAT-UP) is placed in theopen end of the union and supported by means of a screen or perforated metal plate [e.g., a 304-stainless steeldisk, 0.0312-in. (0.8-mm) thick with 1/16-in. (1.6-mm) diameter round perforations at 132 holes per in.2(20 holes/cm2), 41% open area.]. A 32-mm Viton® O-ring is placed between the filter and outer nut to effecta seal (see Figure 3). This filter holder is available from Supelco Park, Bellefonte, PA; SKC, 334 Forty Eight,PA; and other manufacturers.

7.1.5 Size-Selective Impactor Inlet. A size-selective impactor inlet with an average particle-size cut-pointof 2.5 Fm or 10 Fm mean diameter at a sampling rate of 4 L/min may be used to exclude nonrespirable airborneparticulate matter (11). This inlet, particle filter support, sampling cartridge holders are available commerciallyfrom Supelco, Supelco Park, Bellefonte, PA; SKC, 334 Forty Eight, PA and University Research Glassware(URG), Chapel Hill, NC.

7.1.6 Tenax-TA. 60/80 mesh, 2,6-diphenylphenylene oxide polymer. Commercially available fromSupelco, Supelco Park, Bellefonte, PA and SKC, 334 Forty Eight, PA.7.2 Equipment for Analysis

7.2.1 Gas Chromatograph (GC). The GC system should be equipped with appropriate detector(s) andeither an isothermally controlled or temperature programmed heating oven. Improved detection limits may beobtained with a GC equipped with a cool on-column or splitless injector.

7.2.2 Gas Chromatographic Column. As an example, a 0.32 mm (I.D.) x 30 m DB-5, DB-17, DB-608,and DB-1701 are available. Other columns may also provide acceptable results.

7.2.3 HPLC Column. As an example, a 4.6-mm x 25-cm Zorbax SIL or FBondpak C-18. Other columnsmay also provide acceptable results.

7.2.4 Microsyringes. 5 FL volume or other appropriate sizes.7.3 Reagents and Other Materials

7.3.1 Round Bottom Flasks. 500 mL, Ts 24/40 joints, best source.

7.3.2 Capacity Soxhlet Extractors. 300 mL, with reflux condensers, best source.7.3.3 Kuderna-Danish Concentrator. 500 mL, with Snyder columns, best source.7.3.4 Graduated Concentrator Tubes. 10 mL, with 19/22 stoppers, best source.7.3.5 Graduated Concentrator Tubes. 1 mL, with 14/20 stoppers, best source.7.3.6 TFE Fluorocarbon Tape. 1/2 in., best source.7.3.7 Filter Tubes. Size 40 mm (I.D.) x 80 mm.

7.3.8 Serum Vials. 1 mL and 5 mL, fitted with caps lined with TFE fluorocarbon.7.3.9 Pasteur Pipettes. 9 in., best source.

7.3.10 Glass Wool. Fired at 500EC, best source.7.3.11 Boiling Chips. Fired at 500EC, best source..7.3.12 Forceps. Stainless steel, 12 in., best source.

7.3.13 Gloves. Latex or precleaned (5% ether/hexane Soxhlet extracted) cotton.

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7.3.14 Steam Bath.

7.3.15 Heating Mantles. 500 mL.

7.3.16 Analytical Evaporator. Nitrogen blow-down.7.3.17 Acetone. Pesticide quality.7.3.18 n-Hexane. Pesticide quality.

7.3.19 Diethyl Ether. Preserved with 2% ethanol.7.3.20 Sodium Sulfate. Anhydrous analytical grade.7.3.21 Alumina. Activity Grade IV, 100/200 mesh.

7.3.22 Glass Chromatographic Column. 2-mm I.D. x 15-cm long.

7.3.23 Soxhlet Extraction System. Including Soxhlet extractors (500 and 300 mL), variable voltagetransformers, and cooling water source.

7.3.24 Vacuum Oven. Connected to water aspirator.7.3.25 Die.

7.3.26 Ice Chest.

7.3.27 Silicic Acid. Pesticide grade.

7.3.28 Octachloronaphthalene (OCN). Research grade.7.3.29 Florisil. Pesticide grade.

8. Assembly and Calibration of Sampling System8.1 Description of Sampling Apparatus

8.1.1 A typical sampling arrangement utilizing a personal air pump is shown in Figure 1. This method isdesigned to use air sampling pumps capable of pulling air through the sampling cartridge at flow rates of 1 to5 L/min. The method writeup presents the use of this device.

8.1.2 The sampling cartridge (see Figure 2) consists of a glass sampling cartridge in which the PUF plug orPUF/Tenax® TA "sandwich" is retained.8.2 Calibration of Sampling System

8.2.1 Air flow through the sampling system is calibrated by the assembly shown in Figure 4. All air samplermust be calibrated in the laboratory before and after each sample collection period, using the procedure describedbelow.

8.2.2 For accurate calibration, attach the sampling cartridge in-line during calibration. Vinyl bubble tubingor other means (e.g., rubber stopper or glass joint) may be used to connect the large end of the cartridge to thecalibration system. Refer to ASTM Practice D3686 or D4185, for procedures to calibrate small volume airpumps.

9. Preparation of PUF Sampling Cartridges

9.1 The PUF adsorbent is white and yellows upon exposure to light. The "yellowing" of PUF will not affect itsability to collected pesticides or PCBs.

9.2 For initial cleanup and quality assurance purposes, the PUF plug is placed in a Soxhlet extractor andextracted with acetone for 14 to 24 hours at 4 to 6 cycles per hour.

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Pesticides/PCBsMethod TO-10A

Follow with a 16-hour Soxhlet extraction with 5% diethyl ether in n-hexane. When cartridges are reused, 5%diethyl ether in n-hexane can be used as the cleanup solvent.

9.3 Place the extracted PUF in a vacuum oven connected to a water aspirator and dry at room temperature for2 to 4 hours (until no solvent odor is detected). Alternatively, they may be dried at room temperature in an air-tight container with circulating nitrogen (zero grade). Place the clean PUF plug into a labeled glass samplingcartridges using gloves and forceps. Wrap the cartridges with hexane-rinsed aluminum foil and placed in jarsfitted with TFE fluorocarbon-lined caps. The foil wrapping may also be marked for identification using a bluntprobe.

9.4 Granular sorbents may be combined with PUF to extend the range of use to compounds with saturation vaporpressures greater than 10-4 kPa (6). A useful combination trap can be assembled by "sandwiching" 0.6 g ofTenax-TA between two 22-mm I.D. x 3.8-cm pre-cleaned PUF plugs, as shown in Figure 2, Cartridge b. TheTenax-TA should be pre-extracted as described in Section 9.2. This trap may be extracted, vacuum dried, andremoved without unloading it.

9.5 Analyze at least one assembled cartridge from each batch as a laboratory blank before the batch isacceptable. A blank level of <10 ng/plug for single component compounds is considered to be acceptable. Formultiple component mixtures (e.g., PCBs), the blank level should be <100 ng/plug.

9.6 After cleaning, cartridges are considered clean up to 30 days when stored in sealed containers. Certified cleancartridges do not need to be chilled when shipping to the field.

10. Sampling

air samples as described below. The prepared sample cartridges should be used within 30 days ofcertification and should be handled only with latex or precleaned cotton gloves.]

10.1 Carefully remove the clean sample cartridge from the aluminum foil wrapping (the foil is returned to jarsfor later use) and attached to the pump with flexible tubing. The sampling assembly is positioned with the intakedownward or in horizontal position. Locate the sampler in an unobstructed area at least 30 meters from anyobstacle to air flow. The PUF or PUF/XAD-2 cartridge intake is positioned 1 to 2 m above ground level.Cartridge height above ground is recorded on the Compendium Method TO-10A field test data sheet (FTDS),as illustrated in Figure 5.

10.2 After the PUF cartridge is correctly inserted and positioned, the power switch is turned on and the samplingbegins. The elapsed time meter is activated and the start time is recorded. The pumps are checked during thesampling process and any abnormal conditions discovered are recorded on the FTDS. Ambient temperatures andbarometric pressures are measured and recorded periodically during the sampling procedure on the FTDS.10.3 At the end of the desired sampling period, the power is turned off, the PUF cartridge removed from thesampler and wrapped with the original aluminum foil and placed in a sealed, labeled container for transport, underblue ice (<4oC), back to the laboratory. At least one field blank is returned to the laboratory with each group of

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Method TO-10APesticides/PCBs

samples. A field blank is treated exactly like a sample except that no air is drawn through the cartridge. Samplesare stored at <4EC or below until analyzed in the laboratory. Extraction must occur within 7 days of samplingand analysis within 40 days of extraction. Refer to ASTM D4861-94 (1), Appendix X3 for storage stability forvarious common pesticides and other compounds on PUF or PUF/Tenax TA sandwich.

11. Sample Extraction Procedure

11.1 Sample Extraction

11.1.1 All samples should be extracted within 1 week after collection. All samples should be stored at <4ECuntil extracted.

11.1.2 All glassware should be washed with a suitable detergent; rinsed with deionized water, acetone, andhexane; rinsed again with deionized water; and fired in an oven (500EC).

11.1.3 Prepare a spiking solution for determination of extraction efficiency. The spiking solution shouldcontain one or more surrogate compounds that have chemical structures and properties similar to those of theanalytes of interest. Octachloronaphthalene (OCN) and dibutylchlorendate have been used as surrogates fordetermination of organochlorine pesticides by GC with an ECD. Tetrachloro-m-xylene and decachlorobiphenylcan also be used together to insure recovery of early and late eluting compounds. For organophosphate pesticides,tributylphosphate or triphenylphosphate may be employed as surrogates. The surrogate solution should beprepared so that addition of 100 FL into the PUF plug results in an extract containing the surrogate compoundat the high end of the instrument's calibration range. As an example, the spiking solution for OCN is preparedby dissolving 10 mg of OCN in 10 mL of 10% acetone in n-hexane, followed by serial dilution n-hexane toachieve a final spiking solution of OCN of 1 Fg/mL.

[Note: Use the recoveries of the surrogate compounds to monitor for unusual matrix effects and gross sampleprocessing errors. Evaluate surrogate recovery for acceptance by determining whether the measuredconcentration falls within the acceptance limits of 60-120 percent.]

11.1.4 The extracting solution (5% diethyl ether/hexane) is prepared by mixing 1900 mL of freshly openedhexane and 100 mL of freshly opened diethyl ether (preserved with ethanol) to a flask.

11.1.5 All clean glassware, forceps, and other equipment to be used should be rinsed with 5% diethyl ether/hexane and placed on rinsed (5% diethyl ether/hexane) aluminum foil until use. The condensing towers shouldalso be rinsed with 5% diethyl ether/hexane. Then add 300 mL or 5% diethyl ether/hexane to the 500 mL roundbottom boiling flask and add up to three boiling granules.

11.1.6 Using precleaned (i.e., 5% diethyl ether/hexane Soxhlet extracted) cotton gloves, the glass PUFcartridges are removed from the sealed container, the PUF removed from the glass container and is placed intothe 300 mL Soxhlet extractor using prerinsed forceps.

or laboratory tissues (discard) and place cartridge into extractor with intake (large end) downward.]

11.1.7 Before extraction begins, add 100 µL of the OCN solution directly to the top of the PUF plug.

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check to determine recovery efficiency of the extraction and analytical processes.]

11.1.8 Connect the Soxhlet extractor to the 500 mL boiling flask and condenser. Wet the glass joints with5% diethyl ether/hexane to ensure a tight seal between the fittings. If necessary, the PUF plug can be adjustedusing forceps to wedge it midway along the length of the siphon. The above procedure should be followed forall samples, with the inclusion of a blank control sample.

11.1.9 The water flow to the condenser towers of the Soxhlet extraction assembly should be checked and theheating unit turned on. As the samples boil, the Soxhlet extractors should be inspected to ensure that they arefilling and siphoning properly (4 to 6 cycles/hour). Samples should cycle for a minimum of 16 hours.

11.1.10 At the end of the extracting process (minimum of 16 hours), the heating unit is turned off and thesample cooled to room temperature.

11.1.11 The extracts are then concentrated to 5 mL using a Kuderna-Danish (K-D) apparatus. The K-D isset up, assembled with concentrator tubes, and rinsed. The lower end of the filter tube is packed with glass wooland filled with sodium sulfate to a depth of 40 mm. The filter tube is then placed in the neck of the K-D. TheSoxhlet extractors and boiling flasks are carefully removed from the condenser towers and the remaining solventis drained into each boiling flask. Sample extract is carefully poured through the filter tube into the K-D. Eachboiling flask is rinsed three times by swirling hexane along the sides. Once the sample has drained, the filter tubeis rinsed down with hexane. Each Synder column is attached to the K-D and rinsed to wet the joint for a tightseal. The complete K-D apparatus is placed on a steam bath and the sample is evaporated to approximately 5mL.

Remove sample from the steam bath, rinse Synder column with minimum of hexane, and allow to cool. Adjustsample volume to 10 mL in a concentrator tube, close with glass stopper and seal with TFE fluorocarbon tape.Alternatively, the sample may be quantitatively transferred (with concentrator tube rinsing) to prescored vialsand brought up to final volume. Concentrated extracts are stored at <4EC until analyzed. Analysis should occurno later than 40 days after sample extraction.11.2 Sample Cleanup

11.2.1 If polar compounds (from example, organophosphorus and carbamate classes) that interfere withGC/ECD analysis are present, use column chromatographic cleanup or alumina. The sample cleanup will permitthe analysis of most organochlorine pesticides or PCBs.

11.2.2 Before cleanup, the sample extract is carefully reduced to 1 mL using a gentle stream of cleannitrogen.

11.2.3 A glass chromatographic column (2-mm I.D. x 15-cm long) is packed with alumina, activity gradeIV, and rinsed with approximately 20 mL of n-hexane. The concentrated sample extract is placed on the columnand eluted with 10 mL of n-hexane at a rate of 0.5 mL/minute. The eluate volume is adjusted to exactly 10 mLand analyzed as per Section 12.

11.2.4 If both PCBs and organochlorine pesticides are sought, alternate cleanup procedures (5,6) may berequired (i.e., silicic acid).

11.2.5 Finally, class separation and improved specificity can be achieved by column clean-up and separationon Florisil (6).

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Method TO-10APesticides/PCBs

12. Analytical Procedure

12.1 Analysis of Organochlorine Pesticides by Capillary Gas Chromatography with Electron CaptureDetector (GC/ECD)

capture detection (see Table 1). Most of these compounds can be analyzed at concentration of 1 to 50 ng/mLby GC/ECD. The following procedure is appropriate. Analytical methods that have been used to determinepesticides and PCBs collected from air by this procedure have been published (12).]

12.1.1 Select GC column (e.g., 0.3-mm by 30-m DB-5 column) and appropriate GC conditions to separatethe target analytes. Typical operating parameters for this column with splitless injection are: Carrier gas-chromatography grade helium at a flow rate of 1 to 2 mL/min and a column head pressure of 7 to 9 psi (48 to60 kPa); injector temperature of 250EC; detector temperature of 350EC; initial oven temperature of 50EC heldfor 2.0 min., ramped at 15EC/min to 150EC for 8 min, ramped at 10EC/min to 295EC then held for 5 min; purgetime of 1.0 min. A typical injection volume is 2 to 3 FL.

12.1.2 Remove sample extract from the refrigerator and allow to warm to room temperature.

12.1.3 Prepare standard solution from reference materials of known purity. Analytically pure standards oforganochlorine pesticides and PCBs are available from several commercial sources.

12.1.4 Use the standard solutions of the various compounds of interest to determine relative retention times(RRTs) to an internal standard such as p,p'-DDE, aldrin or octachloronaphthalene. Use 1 to 3-FL injections orother appropriate volumes.

12.1.5 Determine detector linearity by injecting standard solutions of three different concentrations (amounts)that bracket the range of analyses. The calibration is considered linear if the relative standard deviation (RSD)of the response factors for the three standards is 20 percent or less.

12.1.6 Calibrate the system with a minimum of three levels of calibration standards in the linear range. Thelow standard should be near the analytical method detection limit. The calibration is considered linear if therelative standard deviation (RSD) of the response factors for the three standards is 20 percent or less. The initialcalibration should be verified by the analysis of a standard from an independent source. Recovery of 85 to 115percent is acceptable. The initial calibration curve should be verified at the begining of each day and after everyten samples by the analysis of the mid point standard; an RPD of 15% or less is acceptable for continuing useof the initial calibration curve.

12.1.7 Inject 1 to 3 FL of the sample extract. Record volume injected to the nearest 0.05 FL.

12.1.8 A typical ECD response for a mixture of single component pesticides using a capillary column isillustrated in Figure 6. If the response (peak height or area) exceeds the calibration range, dilute the extract andreanalyze.

12.1.9 Quantify PCB mixtures by comparison of the total heights or areas of GC peaks (minimum of 5) withthe corresponding peaks in the best-matching standard. Use Aroclor 1242 for early-eluting PCBs and eitherAroclor 1254 or Aroclor 1260 as appropriate for late-eluting PCBs.

12.1.10 If both PCBs and organochlorine pesticides are present in the same sample, use columnchromatographic separation on silicic acid (5,6) prior to GC analysis.

12.1.11 If polar compounds are present that interfere with GC/ECD analysis, use column chromatographiccleanup or alumina, activity grade IV, in accordance with Section 11.2.

12.1.12 For confirmation use a second GC column such as DB-608. All GC procedures except GC/MSrequire second column confirmation.

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Pesticides/PCBsMethod TO-10A

12.1.13 For improved resolution use a capillary column such as an 0.25-mm I.D. x 30-m DB-5 with 0.25 Fmfilm thickness. The following conditions are appropriate.

Helium carrier gas at 1 mL/min.

Column temperature program, 90EC (4 min)/16EC/min to 154EC/4EC/min to 270EC. Detector, 63Ni ECD at 350EC.

Make up gas, nitrogen, or 5% methane/95% argon at 60 mL/min.Splitless injection, 2 FL maximum.Injector temperature, 220EC.

12.1.14 Class separation and improved specificity can be achieved by column chromatographic separationon Florisil (6).

12.2 Analysis of Organophosphorus Pesticides by Capillary Gas Chromatography with FlamePhotometric or Nitrogen-Phosphorus Detectors (GC/FPD/NPD)

flame ionization) detection. Most of these compounds can be analyzed at concentrations of 50 to 500 ng/mLusing either of these detectors.]

12.2.1 Procedures given in Section 12.1.1 through 12.1.9 and Section 12.1.13 through 12.1.14 apply, exceptfor the selection of surrogates.

12.2.2 Use tributylphosphate, triphenylphosphate, or other suitable compound(s) as surrogates to verifyextraction efficiency and to determine RRTs.

12.3 Analysis of Carbamate and Urea Pesticides by Capillary Gas Chromatography with Nitrogen-Phosphorus Detector

12.3.1 Trazine, carbamate, and urea pesticides may be determined by capillary GC (DB-5, DB-17, orDB-1701 stationary phase) using nitrogen-phosphorus detection or MS-SIM with detection limits in the 0.05 to0.2 FL/mL range. Procedures given in Section 12.1.1 through 12.1.9 and Section 12.1.13 through 12.1.14 apply,except for the selection of surrogates, detector, and make up gas.

12.3.2 Thermal degradation may be minimized by reducing the injector temperature to 200EC. HPLC mayalso be used, but detection limits will be higher (1 to 5 Fg/mL).

12.3.3 N-methyl carbamates may be determined using reverse-phase high performance liquidchromatography (HPLC) (C-18) (Section 12.4) and post-column derivatization with o-phthaldehyde andfluorescence detection (EPA Method 531). Detection limits of 0.01 to 0.1 Fg/mL can be achieved.

12.4 Analysis of Carbamate, Urea, Pyrethroid, and Phenolic Pesticides by High Performance LiquidChromatography (HPLC)

analyzed by high HPLC with fixed or variable wavelength UV detection. Either reversed-phase or normalphase chromatography may be used. Detection limits are 0.2 to 10 Fg/mL of extract.]

12.4.1 Select HPLC column (i.e., Zorbax-SIL, 46-mm I.D. x 25-cm, or F-Bondapak C18, 3.9-mm x 30-cm,or equivalent).

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Method TO-10APesticides/PCBs

12.4.2 Select solvent system (i.e., mixtures of methanol or acetonitrile with water or mixtures of heptane orhexane with isopropanol).

12.4.3 Follow analytical procedures given in Sections 12.1.2 through 12.1.9.

12.4.4 If interferences are present, adjust the HPLC solvent system composition or use columnchromatographic clean-up with silica gel, alumina, or Florisil (6).

12.4.5 An electrochemical detector may be used to improve sensitivity for some ureas, carbamates, andphenolics. Much more care is required in using this detector, particularly in removing dissolved oxygen from themobile phase and sample extracts.

12.4.6 Chlorophenol (di- through penta-) may be analyzed by GC/ECD or GC/MS after derivatization withpentafluorobenzylbromide (EPA Method 604).

12.4.7 Chlorinated phenoxyacetic acid herbicides and pentachlorophenol can be analyzed by GC/ECD orGC/MS after derivatization with diazomethane (EPA Method 515). DB-5 and DB-1701 columns (0.25-mm I.D.x 30-m) at 60 to 300EC/4EC per min have been found to perform well.

12.5 Analysis of Pesticides and PCBs by Gas Chromatography with Mass Spectrometry Detection(GC/MS)

identification of pesticides.]

12.5.1 A mass spectrometer operating in the select ion monitoring (SIM) mode can be used as a sensitivedetector for multi-residue determination of a wide variety of pesticides. Mass spectrometers are now availablethat provide detection limits comparable to nitrogen-phosphorus and electron capture detectors.

12.5.2 Most of the pesticides shown in Table 1 have been successfully determined by GC/MS/SIM. TypicalGC operating parameters are as described in Section 12.1.1.

12.5.3 The mass spectrometer is typically operated using positive ion electron impact ionization (70 eV).Other instrumental parameters are instrument specific.

12.5.4 p-Terphenyl-d14 is commonly used as a surrogate for GC/MS analysis.

12.5.5 Quantification is typically performed using an internal standard method. 1,4-Dichlorobenzene,naphthalene-d8, acenaphthene-d10, phenanthrene-d10, chrysene-d12 and perylene-d12 are commonly used as internalstandards. Procedures given in Section 12.1.1 through 12.1.9 and Section 12.1.13 through 12.1.14 apply, exceptfor the selection of surrogates, detector, and make up gas.

12.5.6 See ASTM Practice D 3687 for injection technique, determination of relative retention times, andother procedures pertinent to GC and HPLC analyses.12.6 Sample Concentration

12.6.1 If concentrations are too low to detect by the analytical procedure of choice, the extract may beconcentrated to 1 mL or 0.5 mL by carefully controlled evaporation under an inert atmosphere. The followingprocedure is appropriate.

12.6.2 Place K-D concentrator tube in a water bath and analytical evaporator (nitrogen blow-down)apparatus. The water bath temperature should be from 25EC to 50EC.

12.6.3 Adjust nitrogen flow through hypodermic needle to provide a gentle stream.

12.6.4 Carefully lower hypodermic needle into the concentrator tube to a distance of about 1 cm above theliquid level.

12.6.5 Continue to adjust needle placement as liquid level decreases.12.6.6 Reduce volume to slightly below desired level.

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Pesticides/PCBsMethod TO-10A

12.6.7 Adjust to final volume by carefully rinsing needle tip and concentrator tube well with solvent (usuallyn-hexane).

13. Calculations

13.1 Determination of Concentration

13.1.1 The concentration of the analyte in the extract solution can be taken from a standard curve where peakheight or area is plotted linearly against concentration in nanograms per milliliter (ng/mL). If the detectorresponse is known to be linear, a single point is used as a calculation constant.

13.1.2 From the standard curve, determine the nanograms of analyte standard equivalent to the peak heightor area for a particular compound.

13.1.3 Ascertain whether the field blank is contaminated. Blank levels should not exceed 10 ng/sample fororganochlorine pesticides or 100 ng/sample for PCBs and other pesticides. If the blank has been contaminated,the sampling series must be held suspect.

13.1.4 Quantity of the compound in the sample (A) is calculated using the following equation:

A'

1000

where:

A =total amount of analyte in the sample, ng.

As =calculated amount of material injected onto the chromatograph based on calibration

curve for injected standards, ng.Ve =final volume of extract, mL.Vi =volume of extract injected, FL.

1000 =factor for converting microliters to milliliters.

13.1.5 The extraction efficiency (EE) is determined from the recovery of surrogate spike as follows:

EE(%)

'

where:

EE =S =Sa =

extraction efficiency, %.

amount of spike recovered, ng.amount of spike added to plug, ng.

The extraction efficiency (surrogate recovery) must fall between 60-120% to be acceptable.

13.1.6 The total volume of air sampled under ambient conditions is determined using the following equation:

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Method TO-10APesticides/PCBs

Va'

i'1

j(TixFi)

n

1000L/m3

where:

Va =total volume of air sampled, m3.

Ti =length of sampling segment between flow checks, min.Fi =average flow during sampling segment, L/min.

13.1.7 The air volume is corrected to EPA standard temperature (25EC) and standard pressure (760 mm Hg)as follows:

Vs'V

a

where:

Vs =volume of air at standard conditions (25EC and 760 mm Hg), std. m3.Va =total volume of air sampled, m3.

Pb =average ambient barometric pressure, mm Hg.

Pw =vapor pressure of water at calibration temperature, mm Hg.tA =average ambient temperature, EC + 273.

13.1.8 If the proper criteria for a sample have been met, concentration of the compound in a standard cubicmeter of air sampled is calculated as follows:

Ca(ng/std.m3)

'

where:

SE =sampling efficiency as determined by the procedure outlined in Section 14.

If it is desired to convert the air concentration value to parts per trillion (ppt) in dry air at standardtemperature and pressure (STP), the following conversion is used:

ppt = 0.844 (Ca)

The air concentration can be converted to parts per trillion (v/v) in air at STP as follows:

pptv

'

where:

MW =molecular weight of the compound of interest, g/g-mole.

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Pesticides/PCBsMethod TO-10A

13.1.9 If quantification is performed using an internal standard, a relative response factor (RRF) is calculatedby the equation:

RRF

'

where:

Is =integrated area of the target analyte peak, counts.Iis =integrated area of the internal standard peak, counts.Cis =concentration of the internal standard, ng/FL.Cs =concentration of the analyte, ng/µL.

13.1.10 The concentration of the analyte (Ca) in the sample is then calculated as follows:

Ca'

where:

(Is)(Cis)(RRF)(Iis)

Ca =concentration of analyte, ng/m3

Is =integrated area of the target analyte peak, counts.RRF =relative response factor (see Section 13.1.10).

14. Sampling and Retention Efficiencies14.1 General

14.1.1 Before using Compendium Method TO-10A, the user should determine the sampling efficiency forthe compound of interest. The sampling efficiencies shown in Tables 2, 3, 4, and 5 were determined forapproximately 1 m3 of air at about 25EC, sampled at 3.8 L/min. The SE values in these tables may be used forsimilar sampling conditions; for other compounds or conditions, SE values must be determined.

14.1.2 Sampling efficiencies for the pesticides shown in Table 6 are for a flowrate of 3.8 L/min and at 25EC.For compounds not listed, longer sampling times, different flow rates, or other air temperatures, the followingprocedure may be used to determine sampling efficiencies.14.2 Determining SE

14.2.1 SE is determined by a modified impinger assembly attached to the sampler pump, as illustrated inFigure 7. A clean PUF is placed in the pre-filter location and the inlet is attached to a nitrogen line. oxidation would not necessarily reflect what may be encountered during actual sampling and may givemisleading sampling efficiencies.]

Two PUF plugs (22-mm x 7.6-cm) are placed in the primary and secondary traps and are attached to the pump.

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