METHOD 8020A AROMATIC VOLATILE ORGANICS BY GAS CHROMATOGRAPHY
1.0 SCOPE AND APPLICATION 1.1 Method 8020 is used to determine the concentration of various aromatic volatile organic compounds. Thefollowing compounds can be determined by this method: Appropriate Technique Direct Compound Name CAS No. a Purge-and-Trap Injection
Benzene 71-43-2 b b Chlorobenzene 108-90-7 b b 1,2-Dichlorobenzene 95-50-1 b b 1,3-Dichlorobenzene 541-73-1 b b 1,4-Dichlorobenzene 106-46-7 b b Ethylbenzene 100-41-4 b b Toluene 108-88-3 b b Xylenes b b
a Chemical Abstract Services Registry Number. b adequate response bythis technique. 1.2 Table 1 lists the method detection limit for each target analyte in organic-free reagentwater. Table 2lists the estimated quantitation limit (EQL) for other matrices.
2.0 SUMMARY OF METHOD 2.1 Method 8020provides chromatographic conditions for the detection of aromatic volatile compounds. Samples can be introduced into the GC using direct injection or purge-and-trap (Method 5030). Ground water samples must be determined using Method 5030. A temperature program is used in the gas chromatograph to separate the organic compounds. Detection is achieved by a photo-ionization detector (PID). 2.2 Ifinterferences are encountered, the method provides an optional gas chromatographic column that may be helpful in resolving the analytes from the interferences and for analyte confirmation.
3.0 INTERFERENCES 3.1 Refer to Method 5030 and 8000. CD-ROM 8020A

- 1 Revision 1 September 19943.2 Samples can be contaminated by diffusion of volatile organics (particularly chlorofluorocarbons and methylene chloride) through the sample container septumduring shipmentand storage. Afield sample blank prepared from organic-free reagent water and carried through sampling and subsequent storage and handling can serve as a check on such contamination.
4.0 APPARATUS AND MATERIALS 4.1 Gas chromatograph 4.1.1 Gas Chromatograph

- Analytical system complete with gas chromatograph suitable for on-column injections or purge-and-trap sample introduction and all required accessories, including detectors, column supplies, recorder, gases, and syringes. AData system for measuring peak heights and/or peak areas is recommended. 4.1.2 Columns 4.1.2.1 Column 1: 6 ft x0.082 in ID #304 stainless steel or glass column packed with 5% SP-1200 and 1.75% Bentone-34 on 100/120 mesh Supelcoport, or equivalent. 4.1.2.2 Column 2: 8 ft x 0.1 in ID stainless steel or glass column packed with 5% 1,2,3-Tris(2-cyanoethoxy)propane on 60/80 mesh Chromosorb W-AW, or equivalent. 4.1.3 Detector

- Photoionization (PID) (h-Nu Systems, Inc. Model PI-51-02 or equivalent). 4.2 Sample introduction apparatus Refer to Method 5030 for the appropriate equipment for sample introduction purposes. 4.3 Syringes

- A 5mL Luerlok glass hypodermic and a 5mL, gas-tight with shutoff valve. 4.4 stoppers. Volumetric flask, Class A

- Appropriate sizes with ground glass
4.5 Microsyringe - 10 and 25**~L** with a 0.006 in ID needle (Hamilton 702N or equivalent) and a 100**~L.** 4.6 Analytical balance

- O.OODI g.
5.0 REAGENTS 5.1 Organic-free reagent water. All references to water in this method refer to organic-free reagent water, as defined in Chapter One. 5.2 Methanol (CH30H) - pesticide quality or equivalent. Store away from other solvents. CD-ROM 8020A - 2 Revision 1 September 19945.3 Stock standards

- Stock solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standards in methanol using assayed liquids. Because of the toxicity of benzene and 1,4-dichlorobenzene, primary dilutions of these materials should be prepared in a hood. 5.3.1 Place about 9.8 mL of methanol in a 10mL tQred ground glass stoppered volumetric flask. Allow the flask to stand,**~nstoppered,** for about 10min or until all alcohol wetted surfaces have dried. Weigh the flask to the nearest 0.0001 g. 5.3.2 Using a 100**~L** syringe, immediately add two or moredrops of assayed reference material to the flask; then reweigh. The liquid must fall directly into the alcohol without contacting the neck of the flask. 5.3.3 Reweigh, dilute to volume, stopper, andthen mix byinverting the flask several times. Calculate the concentration in milligrams per liter (mg/L) fromthe net gain in weight. When compound purity is assayed to be 96% or greater, the weight may be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards may be used at any concentration ifthey are certified by the manufacturer or by an independent source. 5.3.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store, with minimal headspace, at 4°C andprotect from light.5.3.5 All standards must be replaced after 6months, or sooner if comparison with check standards indicates a problem. 5.4 Secondary dilution standards: Using stock standard solutions, prepare in methanol secondary dilution standards, as needed, that contain the compounds of interest, either singly or mixedtogether. The secondary dilution standards should beprepared at concentrations such that the aqueous calibration standards prepared in Section 5.5 will bracket the working range of the analytical system. Secondary dilution standards should be stored with minimal headspace for volatiles andshould be checked frequently for signs ofdegradation or evaporation, especially just prior to preparing calibration standards from them. 5.5**Cali~ration** standards: Calibration standards at amlnlmum of five concentrations are prepared in organic-free reagent water from the secondary di1ution of the stock standards. One of the concentrations shoul d be at a concentration near, but above, the method detection limit. The remaining concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the GC. Each standard should contain each analyte for detection bythis method (e.g., some or all of the compounds listed in the target analyte list may be included). In order to prepare accurate aqueous standard solutions, the following precautions must be observed. 5.5.1 Do not inject more than 20**~L** of alcoholic standards into CD-ROM 8020A - 3 Revision 1 September 1994100 mL of organic-free reagent water. 5.5.2 Use a 25**~L** Hamilton 702N microsyringe or equivalent (variations in needle geometry will adversely affect the ability to deliver reproducible volumes ofmethanolic standards into water). 5.5.3 Rapidly inject the alcoholic standard into the filled volumetric flask. Remove the needle as fast as possible after injection. 5.5.4 Mix aqueous standards byinverting theflask three times only. 5.5.5 Fill the sample syringe fromthe standard solution contained in the expanded area of the flask Cdo not use any solution contained in the neck of the flask). 5.5.6 Never use pipets to dilute or transfer samples or aqueous standards. 5.5.7 Aqueous standards are not stable andshould bediscarded after 1 hr, unless properly sealed and stored. The aqueous standards can be stored upto 24 hr, if held in sealed vials with zero headspace. 5.6 Internal standards (if internal standard calibration is used): To use this approach, the analyst must select one or moreinternal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is**~pplicable** to all samples. Alpha ,alpha,alpha-t r iflu0rot01uene has been usedsuccessfully as an internal standard. 5. 6. 1 Prepare calibra t i on standards at a rmn1m urn of f i ve concentrations for each parameter ofinterest as described in Section 5.5. 5.6.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 5.3 and 5.4. It is recommended that the secondary dilution standard be prepared at a concentration of 15mg/L of each internal standard compound. Theaddition of 10**~L** of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30**~g/L.** 5.6_3 Analyze each calibration standard according to Section 7.0, adding 10**~L** of internal standard spiking solution directly to the syringe. 5.7 Surrogate standards: The analyst should monitor both the performance ofthe analytical systemandthe effectiveness ofthe method in dealing with each sample matrix by spiking each sample, standard, and organic-free reagent water blankwith surrogate compounds Cbromochlorobenzene, bromofluorobenzene. 1,1.1- t r iflu0rot01uene , flu0robenzen e, and diflu0robenzenearerec0mmended) whi ch encompass the range of the temperature program used in this method. From stock standard solutions prepared as in Section 5.3, add a volume to give 750**~g** of 

### CD-ROM 8020A - 4 Revision 1 September 1994each surrogate to 45 mL of organic-free reagent water contained in a 50 mL volumetric flask, mix, anddilute to volumefor aconcentration of 15**ng/~L.** Add 10**~L** of this surrogate spiking solution directly into the 5 mL syringe with every sample and reference standard analyzed. If the internal standard calibration procedure is used, the surrogate compounds may be added directly to the internal standard spiking solution (Section 5.6.2).
6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING 6.1 See the introductory material to this chapter, Organic Analytes, Section 4.1.
7.0 PROCEDURE 7.1 Volatile compounds are introduced into the gas chromatograph either by direct injection or purge-and-trap (Method 5030). Method 5030 may be used directly on ground water samples or low-concentration contaminated soils and sediments. Formedium-concentration soils or sediments, methanolic extraction, as described in Method 5030, may be necessary prior to purge-and-trap analysis. Method 5030 also provides guidance onthe analysis of aqueous miscible and nonaqueous miscible liquid wastes (see Section 7.4.1.1 below). 7.2 Gas chromatography conditions (Recommended): 7.2.1 Column 1: Carrier gas (He) flow rate: For lower boiling compounds: Initial temperature: Temperature program: For higher boiling range of Initial temperature: Temperature program: 36mL/min 50°C, hold for 2 min; 50°C to 90°C at 6 a C/min, hold until all compounds have eluted. compounds: 50°C, hold for 2 min; 50°C to 110DC at 3 DC/min, hold until all compounds have eluted. Column 1 provides outstanding separations for a wide variety of aromatic hydrocarbons. Column 1 should be used as the primary analytical column because of its unique ability to resolve para-. meta-, and orthoaromatic isomers. 7.2.2 Column 2: Carrier gas \He) flow rate: Initial temperature: Temperature program: 30

### mumin 40°C, hold for 2 min; 40°C to 100DC at 2DC/min, hold until all compounds have eluted. Column 2, an extremely high polarity column, has been used for a number of years to resolve aromatic hydrocarbons from alkanes in complex CD-ROM 8020A

- 5 Revision 1 September 1994samples. However. because resolution between some of the aromatics is not as efficient as with Column 1. Column 2 should beused**~s** a confirmatory column. 7.3 Calibration: Refer to Method 8000for proper calibration techniques. Use Table 1 and especially Table 2for guidance on selecting the lowest point on the calibration curve. 7.3.1 Calibration musttake place using the same sampleintroduction method that will be used to analyze actual samples (see Section 7.4.1). 7.3.2 The procedure for internal or external calibration may be used. Refer to Method 8000for adescription of each of these procedures. 7.4 Gas chromatographic analysis: 7.4.1 Introduce volatile compounds into the gas chromatograph using either Method 5030(purge-and-trap method) or the direct injectionmethod. If the internal standard calibration technique is used, add 10**~L** of internal standard to the sample prior to purging. 7. 4.1.1 0irectinject i on: In ve ry 1i mit ed app1icati ons (e.g., aqueous process wastes), direct injection of the sample into the GC system with a 10**~L** syringe may be appropriate. The detection limitis very high (approximately 10,000**~gjL)~** therefore, it is only permitted when concentrations in excess of 10,000**~g/L** are expected or for water soluble compounds that do not purge. The system must becalibrated bydirect injection (bypassing the purgeand-trap device). Non-aqueous miscible wastes may also be analyzed by direct injection if the concentration of target analytes in the sample falls within the calibration range. If dilution of the sample is necessary, follow the guidance for High Concentration samples in Method 5030, Section 7.3.3.2. 7.4_2 Method 8000 provides instructions onthe analysis sequence, appropriate dilutions, establishing daily retention time windows, and identification criteria. Include amid-concentration standard after each group of 10 samples in the analysis sequence. 7.4.3 Table 1 summarizes the estimated retention times anddetection limits for anumber of organic compounds ana1yzable using this method. An example of the separation achieved by Column 1 is shown in Figure 1. Figure 2 shows an example of the separation achieved using Column 2. 7.4.4 Recordthe sample volumepurged or injected andthe resulting peak sizes (in area units or peak heights). 7.4.5 Calculation of concentration is covered in Method 8000.

CD-ROM 8020A - 6 Revision 1 September 19947.4.6 If analytical interferences are suspected, or for the purpose of confirmation, analysis using the second GC column is recommended. 7.4.7 If the response for a peak is off scale, i.e., beyond the calibration range of the standards, prepare a dilution of the sample with organic-free reagent water. The dilution must be performed on a second aliquot of the sample which has been properly sealed and stored prior to use.
8.0 QUALITY CONTROL 8.1 Refer to Chapter One for specific quality control procedures and Method 8000 for gas chromatographic procedures. Quality control to ensure the proper operation of the purge-and-trap device is covered in Method 5030. 8.2 Quality control required to validate the GC system operation lS found in Method 8000. 8.2.1 The quality control check sample concentrate (Method 8000) should contain each parameter of interest at a concentration of 10 mg/L in methanol. 8.2.2 Table 3 indicates the calibration and QC acceptance criteria for this method. Table 4gives method accuracy and precision as functions of concentration for the analytes of interest. The contents of both tables should be used to evaluate a laboratory's ability to perform and generate acceptable data bythis method. 8.3 Calculate surrogate standard recovery on all samples, blanks, and spikes. Determine ifrecovery is within limits (limits established byperforming OC procedure outlined in Method8000). 8.3.1 If recovery is not within limits, the following is required. Check to be sure that there are no errors in calculations, surrogate solutions and internal standards. Also, check instrument performance. Recalculate the data and/or reanalyze the extract ifany of the above checks reveal a problem. Reextract and reanalyze the sample if none of the above are a problem or flag the data as "estimated concentration"

. 9.0 METHOD PERFORMANCE 9.1 This methodwas tested by 20laboratories using organic-free reagent water, drinking water, surface water, andthree industrial wastewaters spiked at six concentrations over the range 2.1 - 500**~g/L.** Single operator precision, CD-ROM 8020A - 7 Revision 1 September 1994overall pr.eciston, and method accuracy were found to be directly related to the concentration of the parameter andessentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 4. 9.2 Theaccuracy andprecision obtainedwill be determined bythe sample matrix. sample introduction technique, andby the calibration procedure used. 9.3 The methoddetection limits reported in Table 1 were generated under optimum analytical conditions by anAgency contractor (Ref. 7) as guidance, and may not be readily achievable byall laboratories at all times.
10.0 REFERENCES 1.**Bell~r,** T_A., and J.J. Lichtenberg, J. Amer. Water Works Assoc.• 66(12), pp. 739-744, 1974. 2. Bellar, T.A., and J.J. Lichtenberg, "Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds". in Van Hall (ed.), Measu(ement of Organic Pollutants in Water andWastewater, ASTM STP 686, pp. 108-129, 1979. 3. Dowty, B.J., S.R. Antoine, andJ.L. Laseter, "Quantitative andQualitative Analysis of Purgeable. Organi cs by High Resolution Gas Chromatography and Flame Ionization Detection". in Van Hall, ed., Measurement of Organic Pollutants in Water and Wastewater. ASTM STP 686, pp. 24-35, 1979. 4. Development andApplicatioh of Test Procedures for Specific Organic Toxic Substances in Wastewaters. Category 11

- Purgeables and Category 12

- Acrolein, Acrylo.nitrile, and Dichlorodifluoromethane. Report for EPA Contract 68-03-2635. 5. "EPA Method Validation Study 24, Method 602 (Purgeable Aromatics)", report for EPA Contract 68-03-2856. 6. U.S. EPA 40CFR Part 136, "Guidelines Establishing Test Procedures for the Analysis of Pollutants Underthe Clean Water Act; Final Rule and Interim Final Rule and Proposed Rule", October**26~** 1984. 7. Gebhart. J.E., S.V. Lucas, S.J. Naber, A.M. Berry, T.H. Danison and H.M. Burkholder, "Validation of SW-846 Methods 8010, 8015, and 8020"; Report for EPA Contract 68-03-1760, Work Assignment 2-15; US EPA, EMSLCincinnati, 1987."

CD-ROM 8020A - 8 Revision 1 September 1994TABLE 1. CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION LIMITS FOR AROMATIC VOLATILE ORGANICS

Retention time Method (min) detection 1trmt" Compound Col . 1 Co1 . 2**(~g/L)** Benzene 3.33 2.75 0.2 Chiorcbenzene" 9.17 8.02 0.2 1,4-Dichlorobenzene 16.8 16.2 0.3 1,3-Dichlorobenzene 18.2 15.0 0.4 1,2-Dichlorobenzene 25.9 19.4 0.4 Ethyl Benzene 8.25 6.25 0.2 Toluene 5.75 4.25 0.2 Xylenes a Using purge-and-trap method (Method 5030). See Sec. 9.3. bChlorobenzene and m-xylene may co-elute on some columns.

TABLE 2. DETERMINATION OF ESTIMATED QUANTITATION LIMITS (EQLs) FOR VARIOUS MATRICESa
Matrix
Groundwater Low-concentration soil Water miscible liquid waste High-concentration soil and sludge Non-water miscible waste Factor
10 10 500 1250 1250

a EQL = [Method detection limit (see Table I)J X [Factor found in this tableJ. For non-aqueous samples, the factor is on a wet-weight basis. Sample EQLs are highly matrix-dependent. The EQLs determined herein are provided for guidance and may not always be achievable.
CD-ROM 8020A

- 9 Revision 1 September 1994TABLE 3. OC ACCEPTANCE CRITERIAa
Range Limit Rang£ Range for 0 for s for x P, P s Parameter**(~g/U** (fJg/U (fJg/U (%)
Benzene 15.4-24.6 4.1 10.0-27.9 39-150 Chlorobenzene 16.1-23.9 3.5 12.7-25.4 55-135 1,2-Dichlorobenzene 13.6-26.4 5.8 10.6-27.6 37-154 1,3-Dichlorobenzene 14.5-25.5 5.0 12.8-25.5 50-141 1,4-Dichlorobenzene 13.9-26.1 5.5 11.6-25.5 42-143 Ethylbenzene 12.6-27.4 6.7 10.0-28.2 32-160 Toluene 15.5-24.5 4.0 11 . 2-27.7 46-148 Q Concentration measured in QC check sample, in fJg/L.
s Standard deviation of four recovery measurements, in**~g/L.** x Average recovery for four recovery measurements, in**~g/L.** P, P s Percent recovery measured.
a Criteria from 40 CFR Part 136 for Meth{)d 602, using packed columns, and were calculated assuming a check sample concentration of 20**~g/L.** These criteria are based directly uponthe method performance data in Table 4. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 1. When capillary columns are used, see Method 8021 for performance data.

CD-ROM 8020A - 10 Revision 1 September 1994TABLE 4. METHOD ACCURACY AND PRECISION AS FUNCTIONS OF CONCENTRATION

Parameter
Benzene Chlorobenzene 1,2-Dichlorobenzene 1,3-Dichlorobenzene 1,4-Dichlorobenzene Ethylbenzene Toluene Accuracy, as recovery, x·**(~g** /l)

0.92C+0.57 0.95C+0.02 0.93C+0.52 0.96C-0.04 0.93C-0.09 0.94C+0.31 0.94C+0.65 Single analyst precision, sr'**(~g/l)** 0.09X+0.59 0.09x+0.23 0.lh.-0.04 0.15x.-0.10 

## o.15x.+0. 28 0.17x.+0.46 0.09x+0.48 Overall precision, S'**(~g/l)**
O.2lx.+0.56 0.17x.+0.l0 0.22x.+0.53 0.19x.+0.09 0.20x.+0.41 0.26x.+0.23 O.18x+0. 71

x'

s .

r
S'

C

x Expected recovery for one or more measurements of a sample containing concentration C, in**~g/L.** Expected single analyst st.andard deviation of measurements at an average concentration of

### x, in**~g/L.** Expected interlaboratory**standa~d** deviation of measurements at an average concentration found of x, in**~g/L.** True value for the concentration, in**~g/L.** Average recovery found for measurements of samples containing a concentration of 

### C, in**~g/L.**

CD-ROM 8020A - 11 Revision 1 September 1994CD-ROM Figure 1 Chromatogram of Aromatic Volatile Organics (column 1 conditions)

8020A - 12 Revision 1 September 1994Figure 2 Chromatogram of Aromatic Volatile Organics (column 2 conditions)

Column: Program: Detector: Sample: 5% 1,2,3-Tris(2-Cyanoethoxy)Propane on Chromosorb-W 40°C-2 Minutes, 2°e/Min. to lOOoe Photoionization 2.0 pg/L Standard Mixture 

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CD-ROM B020A - 13 Revision 1 September 1994

### METHOD 8020A AROMATIC VOLATILE ORGANICS BY GAS CHROMATOGRAPHY

Start

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### "' ,I,,-
7.1 Introducecompounds into gaschromatograph 7.4.4Recordvolume

bydirectinjection or purge-and-trap purged orinjected (Method 5030) and peaksizes.


### 'w- 'w7.2Setgas 7.4.5 Calculate chromatograph concentration

condition. (referto Method 8000) ,W- I"

7.3 Celibrate (referto Method8000) 7.4.6Are analytical Yes

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### CD-ROM 8020A - 14 Revision 1 

### September 1994