1、Designation: D 6886 03Standard Test Method forSpeciation of the Volatile Organic Compounds (VOCs) inLow VOC Content Waterborne Air-Dry Coatings by GasChromatograpy1This standard is issued under the fixed designation D 6886; the number immediately following the designation indicates the year oforigin
2、al 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 is for the determination of the weightpercent o
3、f individual volatile organic compounds in low VOCcontent waterborne latex air-dry coatings. The method isintended primarily for analysis of waterborne coatings in whichthe material VOC content is below 5 weight percent. Themethod has been used successfully with higher VOC contentwaterborne coatings
4、.1.2 This method may also be used to measure the exemptvolatile organic compound content (acetone, methyl acetate,and p-chlorobezotrifluoride) of waterborne coatings. The meth-odology is virtually identical to that used in Test MethodD 6133 and similar to that used in Test Method D 6438.1.3 Volatile
5、 compounds that are present at the 0.05 weightpercent level or greater can be determined. Solid phasemicroextraction will detect volatile compounds at lower levels.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
6、 user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1475 Test Method for Density of Liquid Coatings, Inks,and Related Products2D 2369 Test Method for Volatile
7、Content of Coatings2D 3792 Test Method for Water Content of Coatings byDirect Injection Into a Gas Chromatograph2D 3925 Practice for Sampling Liquid Paints and RelatedPigmented Coatings2D 3960 Practice for Determining Volatile Organic Com-pound (VOC) Content of Paints and Related Coatings2D 4017 Tes
8、t Method for Water in Paints and Paint Materialsby Karl Fischer Method2D 6133 Test Method for Acetone p-ChlorobenzotrifluorideMethyl Acetate or t-Butyl Acetate Content of Solventborneand Waterborne Paints, Coatings, Resins, and Raw Mate-rials by Direct Injection into A Gas Chromatograph2D 6438 Test
9、Method for Acetone, Methyl Acetate, andParachlorobenzotrifluoride Content of Paints, and Coat-ings by Solid Phase Microextraction-Gas Chromatogra-phy2E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Prec
10、ision of a Test Method33. Terminology3.1 Abbreviations:3.1.1 CW/DVBCarbowaxy/divinylbenzene3.1.2 DB2-(2-butoxyethoxy)ethanol; Butyl Carbitoly;diethylene glycol monobutyl ether3.1.3 EB2-butoxyethanol; Butyl Cellosolvey; ethyleneglycol monobutyl ether3.1.4 EGethylene glycol3.1.5 FIDflame ionization de
11、tector3.1.6 F-VOCformulation data calculated volatile organiccompound in g/(L-water)3.1.7 GCgas chromatograph3.1.8 PGpropylene glycol3.1.9 % RSDpercent relative standard deviation3.1.10 SPMEsolid phase microextraction3.1.11 Std Devstandard deviation3.1.12 TX2,2,4-trimethypentane-1,3-diol, monoisobu-
12、tyrate; Texanoly3.1.13 VOCvolatile organic compound3.1.14 X-VOCexperimental volatile organic compound ing/(L-water)4. Summary of Test Method4.1 A known weight of coating is dispersed in tetrahydro-furan (THF), internally standardized, and analyzed by capillarygas chromatography to give a speciated c
13、omposition of thevolatile organic compounds and exempt organic compounds, if1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Mate
14、rials.Current edition approved March 10, 2003. Published May 2003.2Annual Book of ASTM Standards, Vol 06.01.3Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.any, present in the coating. Summat
15、ion of the individualvolatile organic compound weight fractions gives the totalVOC content of the coating measured in weight percent (Note1).NOTE 1Using the provisions of Practice D 3960, the VOC content ofcoatings measured in g/L minus water, or other units, may be determined.Since the determinatio
16、n of weight percent VOC in the present method isby direct measurement, either the water fraction (Test Method D 3792 orTest Method D 4017) or the nonvolatile fraction (Test Method D 2369)may be determined indirectly in the application of Practice D 3960. Theequations for calculating regulatory VOC c
17、ontent when no exempt volatilecompounds are present are:VOC 5fVOCDP!1 2 1 2 fNV2 fVOC!DP/DW!#(1)orVOC 5fVOCDP!1 2 fWDP/DW!#(2)where:DP,fNV,fVOC, and fW= coating density, nonvolatile fraction,VOC fraction, and water fraction, respec-tively.4.2 Direct GC/FID, GC/MS and solid phase microextraction/ gas
18、 chromatography (SPME/GC) of the coating may be usedto facilitate identification of the volatile compounds present ina coating. Table X1.1 lists the GC retention times for thevolatile compounds which may be found in low VOC contentwaterborne air-dry coatings. Table X1.1 also lists possibleinternal s
19、tandards for use in the analysis and minor volatilecomponents which are sometimes found in waterborne coat-ings (Note 2).NOTE 2The analyst should consult MSDS and product data sheets forpossible information regarding solvents which may be present in aparticular coating. SPME/GC may be used to ascert
20、ain that decompositionvolatiles are not measured.5. Significance and Use5.1 In using Practice D 3960 to measure the regulatory VOCcontent of coatings, precision tends to be poor for low VOCcontent waterborne coatings because the VOC weight fractionis determined indirectly. The present method first i
21、dentifies andthen quantifies the weight fraction of individual VOCs directlyin low VOC content waterborne air-dry coatings. The totalVOC weight fraction can be obtained by adding the individualweight fraction values (Note 3).NOTE 3An effort is currently underway in California to considerchanging mas
22、s-based VOC regulations for architectural coatings toreactivity-based VOC regulations. In California, reactivity based regula-tions have already been implemented for aerosol coatings, that is,MIR-indexed regulations (California Air Resources Board). Reactivitybased regulations would require knowing
23、the weight fractions of eachindividual volatile compound present in a coating.5.2 SPME/GC makes it possible to identify very low levelsof volatile compounds in a coating and could serve to make itpossible to identify the presence of hazardous air pollutants(HAPs).6. Apparatus6.1 SPME Sampling Appara
24、tus and Fibers,4manualSPME holders fitted with a 70 m Carbowaxy/Divinylbenzene(CW/DVB) StableFlex fiber assembly.6.2 Gas Chromatograph, FID Detection with ElectronicData Acquisition SystemAny capillary gas chromatographequipped with a flame ionization detector and temperatureprogramming capability m
25、ay be used. Electronic flow control,which gives a constant carrier gas flow, is highly recom-mended.6.3 Standard FID Instrument Conditions:Detector Flame ionizationColumns Primary column: 30 m by 0.25 mm 5 % phenyl/95 % methylsiloxane (PMPS) (Note 4) , 1.0 m film thickness.Confirmatory Columns: 30 m
26、 by 0.25 mm polydimethylsiloxane(PDMS), 0.25 m film thickness; 30 m by 0.25 mmCarbowaxY (CW), 0.25 m film thickness.Carrier Gas HeliumFlow Rate 1.0 mL per min, constant flow (24.9 cm/s at 40)Split Ratio VariableTemperatures, CInlet 260Detector 270Initial 40 for 4 minRate 10 per min to 250, hold 5 mi
27、nNOTE 4The column designated as PMPS is commercially availablefrom several vendors by the following designations: DB-5, SPB-5, HP-5,AT-5, CP Sil 8CB, RTx-5, BP-5.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, all reagents
28、 shallconform to the available specifications of the Committee onAnalytical Reagents of the American Chemical Society. Othergrades may be used, provided it is first ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.7.2 Car
29、rier Gas, helium of 99.995 % or higher purity.7.3 Tetrahydrofuran (THF), HPLC grade.7.4 1-Propanol, p-fluorotoluene, cyclohexanol,p-chlorotoluene and p-cymene, 99 + mole %.7.5 The volatile organic compounds listed in Table X1.1.7.6 Fluorocarbon-faced septum vials, 20 mL and 40 mLcapacity.8. Column a
30、nd Fiber Conditioning8.1 The capillary columns should be conditioned accordingto the manufacturers recommendation. The columns may thenbe used indefinitely without further conditioning.8.2 The SPME fiber should be conditioned and used accord-ing to the manufacturers recommendation.8.3 The SPME fiber
31、 should be inserted into a 260Cinjection port for 30 s prior to each sampling event.9. Preparation of Standards9.1 Prepare a stock mixture of ethylene glycol (EG), pro-pylene glycol (PG), ethylene glycol monobutyl ether (EB),p-cymene (CY) or other suitable internal standard, diethylene4Available fro
32、m the Supelco Company, Supelco Park, Bellefonte, PA 16823-0048.D6886032glycol monobutyl ether (DB), and Texanol (TX) by weighingone or two grams of each into an appropriate vial. The weightof each component should be approximately the same anddetermined to 0.1 mg. Mix the contents.9.2 Transfer appro
33、ximately 100 L of the stock mixture to aseptum-capped vial containing 10 mL of THF and mix thecontents (Note 5). This solution will contain each of the knownanalytes at a concentration of approximately 2 mg/mL.NOTE 5The solvents EG, PG, EB, DB and Texanol are widely used inthe manufacture of low VOC
34、 content waterborne air-dry coatings and maybe expected as highly probable components of these coatings. Thetetrahydrofuran solvent must be analyzed by GC to determine if possibleimpurities interfere/coelute with the analytes being tested.9.3 Chromatograph the solution in 9.2 by injecting 1 L intoth
35、e PMPS column using the chromatographic conditions givenin 6.3. Calculate the relative response factors for each of theanalytes relative to the p-cymene internal standard using therelationship:RF 5AA * MIAI * MA(3)where:RF = relative response factor,AA = area of analyte,MI = weight of internal stand
36、ard (from 9.1),AI = area of internal standard, andMA = weight of analyte (from 9.1).10. Paint Analysis10.1 Using a 100 mL volumetric flask, make up a concen-trated standard solution containing p-cymene (or other suitableinternal standard) in THF at a concentration of approximately1 g per 100 mL and
37、known to the nearest 0.1 mg.10.2 Using standard quantitative dilution techniques, dilutethe concentrated standard solution to give a working standardsolution such that the internal standard concentration is near 1mg per mL. Calculate the actual concentration.10.3 Pipette 10 mL of working standard so
38、lution into a 20 or40 mL vial and close with a fluorocarbon-faced septum cap.Using a disposable 1 mL syringe, add approximately 0.6 to 0.8g of the well-mixed paint through the septum cap and weigh to0.1 mg (Note 6). Mix the contents vigorously by shaking for 1min followed by sonication for 5 min. Le
39、t the vial stand topermit pigments, if any, to settle.NOTE 6The paint should be drawn into the syringe without anattached syringe needle. Excess paint is wiped from the syringe and theneedle is then attached for paint transfer. The mass of the paint may bedetermined by either the difference in the w
40、eight of the filled and emptysyringe or by the difference in the weight of the vial before and afteradding paint. When adding the paint to the THF in the vial, care should betaken that the paint falls directly into the THF solution containing theinternal standard.10.4 Chromatograph the solution in 1
41、0.3 by injecting 1 Linto the PMPS capillary column using the standard conditionsdescribed in 6.3. Adjust the split ratio to give well-definedchromatographic peaks. Identify the volatile compoundspresent (Note 7) and calculate the weight fraction of each in thecoating using the relationship:%X 5AA!MI
42、!100!AI!RF!MC!(4)where:X = one of several possible volatile compounds in thecoating,RF = relative response factor of compound X,AA = peak area of compound X,MI = weight of internal standard in 10 mL THF,AI = peak area of internal standard, andMC = weight of coating.NOTE 7If volatile compounds other
43、than those in the standard (9.1)are present in the coating, the identity should be confirmed by retentiontime comparison with authentic material and the relative response factorshould be determined as outlined in 9.1-9.3. Commercial Texanol maycontain small amounts of 2,2,4-trimethylpentane-1,3-diol
44、 which elutesapproximately 0.5 min before butyl carbitol. Acetone and isopropylalcohol have nearly the same retention time on a 5 % phenyl/95 % PDMScolumn and if either is found, their identities should be confirmed on adifferent column. Isobutyl alcohol coelutes with the solvent (THF) andmust be de
45、termined on a different column. SPME (11.2) is especiallyuseful for confirming the presence of isobutyl alcohol since no THF isused in this procedure.11. Solid Phase Microextraction Procedure11.1 Since a dispersion of coating in THF is injected into arelatively hot GC injection port, peaks represent
46、ing decompo-sition products may be observed and should not be consideredas VOCs. Solid phase microextraction allows sampling of mostVOCs at low temperature and may be used to determine if GCpeaks observed in the direct GC analysis (Section 10) areactual VOCs or decomposition products. If desired, th
47、e SPMEprocedure may be used prior to direct analysis to determinewhich VOCs are present in the coating. If GC/MS is available,the SPME procedure is especially useful for identification ofVOCs and exempt compounds present in a coating sample.11.2 Place approximately 5 to 10 g of liquid waterbornecoat
48、ing into a 40 mL fluorocarbon-faced septum vial. If usinga smaller vial, reduce the coating amount. Close the vial witha fluorocarbon-faced septum cap and heat to 55 to 60C in anoven or other suitable heat source (oil bath, water bath, heatedmetal block). Do not let the contents contact the inside f
49、ace ofthe septum cap. Insert the SPME fiber through the septum capand sample the headspace for 3 to 4 min using a conditionedCW/DVB SPME fiber. Desorb the fiber for 10 s onto thecapillary column and obtain the gas chromatogram using thestandard chromatographic conditions described in 6.3. Identifythe volatile components present in the liquid paint usingretention time values given in Table X1.1. The peaks found bythis SPME procedure should correspond to the peaks found bythe direct procedure. If peaks found in the direct procedure are
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