ASTM D4457-2002 Standard Test Method for Determination of Dichloromethane and 1 1 1-Trichloroethane in Paints and Coatings by Direct Injection into a Gas Chromatograph《直接注入气相色谱仪法测定.pdf

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1、Designation: D 4457 02Standard Test Method forDetermination of Dichloromethane and 1,1,1-Trichloroethanein Paints and Coatings by Direct Injection into a GasChromatograph1This standard is issued under the fixed designation D 4457; the number immediately following the designation indicates the year o

2、foriginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of totalamount

3、of dichloromethane or 1,1,1-trichloroethane, or both, inpaints and coatings. It has been evaluated for cellulose nitrate,alkyd, vinyl, and styrene-butadiene systems. It has not yet beenevaluated for other formulations, but is believed to be appli-cable. The established working range of this test met

4、hod isfrom 31 to 65 % for 1,1,1-trichloroethane and 32 to 78 % fordichloromethane. There is no reason to believe it will not workoutside of these ranges. The presence of 1-propanol in paintsand coatings requires the use of a different internal standard.(See also Practice E 260.)1.2 The values stated

5、 in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate saf

6、ety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals2E

7、260 Practice for Packed Column Gas Chromatography33. Summary of Test Method3.1 Anhydrous 1-propanol (see 10.5) is added as an internalstandard to suitable aliquot of the whole paint. The aliquot isthen diluted with dimethylformamide and injected onto a gaschromatographic column containing a porous p

8、olymer packingthat separates dichloromethane and 1,1,1-trichloroethane fromother volatile compounds.4. Significance and Use4.1 Use of 1,1,1-trichloroethane and dichloromethane,which do not measurably contribute to the atmospheric oxidantlevel, is a way for industry to meet government or otherregulat

9、ions on volatile organic compounds. This test method isdesigned to determine the content of these halohydrocarbonsolvents in paints and coatings. That content can subsequentlybe used in calculating the volatile organic compound content ofa coating.5. Apparatus5.1 Chromatograph, any gas-liquid chroma

10、tographic instru-ment equipped with a thermal conductivity detector andcapable of being temperature programmed (see Table 1).Optionally, a flame ionization detector may be used if thesample is diluted so that no more than 1000 ppm each ofdichloromethane and 1,1,1-trichloroethane is present in theinj

11、ected specimen.5.2 Recorder, a recording potentiometer with a full-scaledeflection of 10 mV, a full-scale response time of2sorless,and a maximum noise of 60.03 % of full scale.5.3 Pre-Column, 40 in. (100 mm) long by18 in. (3.2 mm)outside diameter stainless steel, packed with glass wool, fittedon the

12、 entrance end of the column to retain any nonvolatilematerials and minimize sludge buildup in the column.5.4 Column, 4 ft (1.22 m) long by18 in. (3.2 mm) outsidediameter stainless steel, packed with 80/100 mesh (150 to 180m) porous polymer packing material,4or other suitablematerial.5.5 Liquid Charg

13、ing Devices, such as microsyringes of 5-Lor 10-L capacity, cleaned with acetone or other suitablesolvent. Visually inspect for plugs or cracks before and aftereach injection.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications an

14、d is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paint and Paint Materials.Current edition approved Jan. 10, 2002. Published March 2002. Originallypublished as D 4457 - 85. Last previous edition D 4457 - 85 (1996)1.2Annual Book of ASTM Standards, Vol 15.05.3Annual Book of

15、 ASTM Standards, Vol 14.02.4Porapak Rt, available from Waters Associates, Inc., Milford, MA, has beenfound satisfactory for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.6 Vials, 25-mL to minimize head space, capable

16、 of beingseptum sealed.56. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests, unless otherwise specified (as in 6.7). Unlessotherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of t

17、he American Chemical Society, where suchspecifications are available.6Other grades may be used pro-vided it is first ascertained that the reagent is of sufficient highpurity to permit its use without lessening the accuracy of thedetermination.6.2 Carrier Gas, helium of 99.995 % or higher purity. Hig

18、hpurity nitrogen may also be used.6.3 Dimethylformamide (DMF), reagent grade.6.4 1-Propanol, gas chromatography spectrophotometricquality (see 10.5).6.5 1,1,1-Trichloroethane (see 6.7).6.6 Dichloromethane (see 6.7).6.7 Halogenated Hydrocarbon StabilizersAll commercialgrades of these halogenated hydr

19、ocarbons contain stabilizers.Either obtain the same solvent used in the coating for use as thestandard, or find the type and quantity of stabilizer specified foruse in the solvent of interest and add the appropriate quantityto the pure solvent.7. Hazards7.1 Dimethylformamide is harmful if inhaled or

20、 absorbedthrough skin. Use only with adequate ventilation. Avoidcontact with skin, eyes, and clothing.8. Preparation of Apparatus8.1 Column ConditioningThe packed column is installedin the gas chromatographic unit leaving the exit end discon-nected from the detector. This will prevent any contaminat

21、ionof the detector with the column bleed. Set the helium flow rateat 30 mL/min if a18 in. (3.2 mm) outside diameter column isused. Purge the column 5 to 10 min before heating. Heat thecolumn from room temperature to 200C at 5C/min and holdthis temperature for at least 12 h (overnight). At the end of

22、 thisperiod of time, heat the column to 240C at a 5C/min rate andhold this temperature for several hours. The maximum tem-perature for this packing is 250C. Cool the column to 100Cand reheat to 240C at 5C/min to observe the column bleed.Optimum conditioning of this column may take several cyclesof t

23、he heating program before a good recorder baseline isachieved. Conditioning of any column other than that sug-gested (5.4) should be in accordance with the manufacturersrecommendations.8.2 Install the column in the chromatograph and use theinformation in Table 1 as a guide to establish the condition

24、srequired to give the desired separation. Allow sufficient timefor the instrument to reach equilibrium as indicated by a stablerecorder baseline. Adjust the carrier-gas flow to a constant rate.Before each calibration and series of determinations (or daily),condition the column at 200C for 1 h with c

25、arrier-gas flow.9. Calibration9.1 Preparation of StandardsAll standards, as well assamples and blanks, should be at a constant temperature. Thegiven order of ingredient addition should be observed tominimize loss of volatile ingredients.9.1.1 Weighing to 1.0 mg, add 16.0 g of dimethylformamideto a v

26、ial capable of being septum sealed. Add 2.0 g of1,1,1-trichloroethane, 2.0 g of 1-propanol (see 10.5) and 2.0 gof dichloromethane. Seal the vial with a crimp-on or septumseal.9.2 Determine the retention time of each component byinjecting small amounts either separately or in known mix-tures. The com

27、ponents should elute close to the typicalretention times given in Table 1 and the chromatograms shouldclosely approximate those shown in Fig. 1.9.3 The area under each peak of the chromatogram isconsidered a quantitative measure of the corresponding com-pound. The relative area is proportional to co

28、ncentration if thedetector responds equally to all the sample components. Theresponse to different components is generally significantlydifferent for both flame ionization and thermal conductivitydetectors and especially for flame ionization detectors. Thisdifference in detector response may be corr

29、ected by use ofrelative response factors obtained by injecting and measuringthe response of known blends. For precise and accuratedetermination of the halogenated hydrocarbons injecta1Lspecimen of the standard in accordance with the preparation in9.1. Calculate the response factors relative to unity

30、 for thehalogenated hydrocarbons.10. Procedure10.1 Keep all samples, blanks, and standards at a constanttemperature. Observe the given order of ingredient addition tominimize loss of volatile ingredients. Shake paints, thensample from the middle of the container.10.2 Weighing to 1.0 mg, add 16.0 g o

31、f dimethylformamide5Mininert valves, available from The Pierce Chemical Co., Box 117, Rockford,IL 61105, have been found satisfactory for this purpose.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents no

32、tlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD. American Chemical Society, see “Reagent Chemicals and Standards,”

33、 byJoseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”TABLE 1 Typical Instrument ConditionsDetector thermal conductivityColumn 4 ft (1.22 m) by18in. (3.2 mm) outsidediameter packed with 80100 meshporous polymer packingTemperature, CInjection port 200Detector b

34、lock 250ColumnInitial 100Final 230 (for 8 min)C/min 8Carrier gas heliumFlow rate, mL/min 30Specimen size, L 1D 44572and 5.0 g of the paint to a vial capable of being septum sealed.Add 2.0 g of 1-propanol (see 10.5). Seal the vial with acrimp-on or septum seal.10.3 Shake the vial. Then to facilitate

35、settling, centrifugeusing a low speed centrifuge at 1000 rpm for 5 min.10.4 Inject a 1-L specimen of the supernatant from theprepared solution onto the chromatographic column, in accor-dance with the conditions established in 8.2. Record the peaksof all components.10.5 If the composition of the pain

36、t is unknown, test for thepresence of 1-propanol. Prepare a blank, omitting the 2.0 g of1-propanol in 10.2, and inject a 1-L specimen. To this blankadd 2.0 g of 1-propanol and inject a 1-L specimen. Thencompare peak response to that from the test solution. If1-propanol is present in the paint, subst

37、itute a different internalstandard. Other possible internal standards include alcohols,esters, and hydrocarbons.10.6 If the composition of the paint is unknown, establishwhether peaks interfering with 1-propanol or the halogenatedhydrocarbons are present by using both the column specified in5.4 and

38、a second column that yields different retention times.711. Calculation11.1 Measure the area of all peaks (Note 1) and multiplyeach area by the appropriate attenuation factor to express thepeak areas on a common basis.NOTE 1Peak areas may be determined by any method that meets theprecision requiremen

39、ts of Section 12. Electronic integration is recom-mended for best results.11.2 Calculate the percent halogenated hydrocarbon in thepaint as follows:RFi5WiAi(1)where:RFi= corrected peak response for ithcomponent, area units,Wi= weight of ithcomponent in the standard solution, g,andAi= chromatographic

40、 peak area for the ithcomponent inthe standard solution, area units,then:CH wt % 5RFCH3 ACH3 ISamtRFIS3 AIS3 W3 100 (2)where:CH wt % = chlorinated hydrocarbon, weight %,RFCH= response factor for the chlorinated hydrocarbonin the standard solution, area units,ACH= area of the chlorinated hydrocarbon

41、peak in thetest solution, area units,ISamt= weight of internal standard added to the paint,g,RFIS= response factor for the internal standard in thestandard solution, area units,AIS= area of the internal standard peak in the testsolution, area units, andW = specimen weight, g.12. Precision and Bias8(

42、see also Practice E 180)12.1 Precision:12.1.1 1,1,1-TrichloroethaneOn the basis of an interlabo-ratory test of this test method in which one operator in each ofeight laboratories tested three coatings containing from 31 to65 % 1,1,1-trichloroethane (theoretical), the within-laboratorycoefficient of

43、variation was found to be 1.01 % relative at 20degrees of freedom and the between-laboratories coefficient ofvariation was found to be 2.72 % relative at 17 degrees offreedom. Based on these coefficients, the following criteriashould be used for judging the acceptability of results at the95 % confid

44、ence level:12.1.1.1 RepeatabilityTwo results, each the mean of du-plicate runs, obtained by the same operator should be consid-ered suspect if they differ by more than 3.0 % relative.12.1.1.2 ReproducibilityTwo results, each the mean ofduplicate runs, obtained by operators in different laboratoriess

45、hould be considered suspect if they differ by more than 8.1 %relative.12.1.2 DichloromethaneOn the basis of an interlaboratorytest of this test method in which one operator in each of eightlaboratories tested two coatings containing from 32 to 78 %dichloromethane (theoretical), the within-laboratory

46、 coefficientof variation was found to be 0.98 % relative at 14 degrees offreedom and the between-laboratories coefficient of variationwas found to be 5.16 % relative at 12 degrees of freedom.Based on these coefficients, the following criteria should be7Packings from the Porapak series and the Chromo

47、sorb Century series may besatisfactory for this purpose. However, it is the responsibility of each analyst tocheck for interferences from paints or the internal standard chosen, or both, and tochoose a column that gives symmetrical peaks.8Supporting data are available from ASTM International Headqua

48、rters. RequestRR:D01 1045.FIG. 1 Typical Chromatograms of PaintsD 44573used for judging the acceptability of results at the 95 %confidence level:12.1.2.1 RepeatabilityTwo results, each the mean of du-plicate runs, obtained by same operator should be consideredsuspect if they differ by more than 3.0

49、% relative.12.1.2.2 ReproducibilityTwo results, each the mean ofduplicate runs, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than17.92 % relative.12.2 BiasBias cannot be determined because there are nostandards for Dichloromethane and 1,1,1Trichloroethane inpaint.13. Keywords13.1 chlorinated hydrocarbons in paints by gas chromato-graph; dichloromethane, in paints; exempted solvent in paints;gas chromatograph, halohydrocarbon; 1,1,1-trichloroethane, inpaintsASTM International takes no position resp