1、Designation: D6886 12Standard Test Method forDetermination of the Individual Volatile Organic Compounds(VOCs) in Air-Dry Coatings by Gas Chromatography1This standard is issued under the fixed designation D6886; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is for the determination of the weightpercent of individual v
3、olatile organic compounds in air-drycoatings.1.2 The method can be used to determine the weightfraction VOC content of waterborne coatings in which thematerial VOC content is below 5 weight percent. The methodhas been used successfully with higher VOC content water-borne coatings and with solvent-bo
4、rne coatings (Note 1).1.3 The method may also be used to measure the exemptvolatile organic compound content (acetone, methyl acetate,t-butyl acetate and p-chlorobezotrifluoride) of waterborne andsolvent-borne coatings. The methodology is virtually identicalto that used in Test Method D6133 which, a
5、s written, is specificfor only exempt volatile compounds.1.4 Volatile compounds that are present at the 0.005 weightpercent level or greater can be determined.NOTE 1This test method may be used for the VOC analysis ofcoatings containing silanes, siloxanes, and silane-siloxane blends. The testmethod
6、is not suitable for the analysis of coatings that cure by chemicalreaction (this includes two-component coatings and coatings which curewhen heated) because dilution with a solvent would impede the chemicalreaction required for these types of coatings. This test method measuresthe VOC weight fractio
7、n of air-dry coatings directly as opposed to themethods of Practice D3960 which measure the VOC weight fraction ofair-dry waterborne coatings indirectly. A direct measurement of VOCweight fraction, particularly in low VOC content waterborne coatings,generally gives better precision. California Polyt
8、echnic State Universitycarried out an extensive study for the California Air Resources Boardcomparing the precision of the direct method with the indirect method(CARB Standard Agreement No. 04.329).2This study may be used todecide if the present method or the methods of Practice D3960 arepreferred a
9、s an analysis method for obtaining the best possible precisionfor measuring the mass-based VOC content of a specific coating.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all o
10、f thesafety concerns, if any, associated with its use. It is theresponsibility of the 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:3D2369 Test Method for V
11、olatile Content of CoatingsD3792 Test Method for Water Content of Coatings byDirect Injection Into a Gas ChromatographD3960 Practice for Determining Volatile Organic Com-pound (VOC) Content of Paints and Related CoatingsD4017 Test Method for Water in Paints and Paint Materialsby Karl Fischer MethodD
12、6133 Test Method for Acetone, p-Chlorobenzotrifluoride,MethylAcetate or t-ButylAcetate Content of Solventborneand Waterborne Paints, Coatings, Resins, and Raw Mate-rials by Direct Injection Into a Gas ChromatographE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice
13、 for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Abbreviations:3.1.1 EGDEethylene glycol diethyl ether3.1.2 DB2-(2-butoxyethoxy)ethanol; Butyl Carbitol;4di-ethylene glycol monobutyl ether3.1.3 EB2-butoxyethanol; Butyl Cellosolve;5ethyleneglycol mon
14、obutyl ether3.1.4 EGethylene glycol3.1.5 FIDflame ionization detector3.1.6 F-VOCformulation data calculated volatile organiccompound in g/(L-water)3.1.7 GCgas chromatograph3.1.8 PGpropylene glycol1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Material
15、s, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved May 1, 2012. Published June 2012. Originallyapproved in 2003. Last previous edition approved in 2009 as D6886 - 03 (2009).DOI: 10.1520/D6886-12.2Deta
16、iled results of this study may be found at http:/www.arb.ca.gov/coatings/arch/Final_Report_6_11_09.pdf.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards
17、 Document Summary page onthe ASTM website.4Butyl Carbitol is a registered trademark of The Dow Chemical Company.5Butyl Cellosolve is a registered trademark of The Dow Chemical Company.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3
18、.1.9 % RSDpercent relative standard deviation3.1.10 SPMEsolid phase microextraction3.1.11 SPDEsolid phase dynamic extraction3.1.12 Std Devstandard deviation3.1.13 TX2,2,4-trimethypentane-1,3-diol, monoisobu-tyrate3.1.14 VOCvolatile organic compound3.1.15 X-VOCexperimental volatile organic compound i
19、ng/(L-water)4. Summary of Test Method4.1 A known weight of coating is dispersed in methanol ortetrahydrofuran (THF) internally standardized, and analyzedby capillary gas chromatography to give a speciated composi-tion of the volatile organic compounds and exempt organiccompounds, if any, present in
20、the coating. Summation of theindividual volatile organic compound weight fractions givesthe total VOC content of the coating measured in weightpercent (Note 2).NOTE 2Methanol should be used as a solvent for all waterbornecoatings. THF should be used for solventborne coatings.Acetone may alsobe used
21、for solventborne coatings but should not be used for waterbornecoatings because it may react with ammonia and amines which arefrequently found in waterborne coatings. Using the provisions of PracticeD3960, the VOC content of coatings measured in g/L minus water, orother units, may be determined. Sin
22、ce the determination of weight percentVOC in the present method is by direct measurement, either the waterfraction (Test Method D3792 or Test Method D4017) or the nonvolatilefraction (Test Method D2369) may be determined indirectly in theapplication of Practice D3960. Since precision is better for t
23、he determi-nation of the nonvolatile content, this is the preferred method for theindirect calculation of water content in this test method. The equations forcalculating coating VOC content when no exempt volatile compounds arepresent are:VOC 5fVOCDP!1 2 1 2 fNV2 fVOC!DP/DW!#(1)orVOC 5fVOCDP!1 2 fWD
24、P/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 chromatography (SPME/GC) of the coating may be usedto facilitate identification of the volatile compounds present in
25、a coating. Table X1.1 lists the GC retention times for thevolatile compounds which may be found in low VOC contentair-dry coatings and several possible internal standards, ordi-narily not present in coatings, which may be used (Note 3).NOTE 3The analyst should consult MSDS and product data sheets fo
26、rpossible information regarding solvents which may be present in aparticular coating. Retention times given in X1.1 must be verified for eachindividual instrument.5. Significance and Use5.1 In using Practice D3960 to measure the VOC content ofwaterborne coatings, precision tends to be poor for low V
27、OCcontent air-dry coatings when the VOC weight fraction isdetermined indirectly. The present method first identifies andthen quantifies the weight fraction of individual VOCs directlyin air-dry coatings. The total VOC weight fraction can beobtained by adding the individual weight fraction values (No
28、te4).NOTE 4The present method may be used to speciate solvent-borneair-dry coatings. However, since these normally contain high, and oftencomplex, quantities of solvent, precision tends to be better using themethods contained in Practice D3960, where the VOC fraction isdetermined by a direct weight
29、loss determination.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 Gas Chromatograph, FID Detection or Mass Spectrom-etry Detection with Electroni
30、c Data Acquisition SystemAnycapillary gas chromatograph equipped with a flame ionizationdetector or mass spectrometer and temperature programmingcapability may be used. Electronic flow control, which gives aconstant carrier gas flow, is highly recommended.6.2 Standard GC/FID and GC/MS Instrument Con
31、ditions:6.2.1 See Table 1.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, all reagents shallconform to the available specifications of the Committee onAnalytical Reagents of the American Chemical Society. Othergrades may b
32、e 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 Carrier Gas, helium of 99.995 % or higher purity.7.3 Tetrahydrofuran (THF), HPLC grade.7.4 Methanol, HPLC grade.7.5 Possible internal stand
33、ards: 1-Propanol,p-fluorotoluene, cyclohexanol, p-chlorotoluene, ethylene glycoldiethylether (EGDE).7.6 Fluorocarbon-faced Septum Vials, 20 mL and 40 mLcapacity.7.7 Ceramic Beads, 0.51.0 mm diameter.8. Column Conditioning8.1 The capillary columns should be conditioned accordingto the manufacturers r
34、ecommendation. The columns may thenbe used indefinitely without further conditioning.9. Preparation of Standards9.1 Prepare a stock mixture of ethylene glycol (EG), pro-pylene glycol (PG), ethylene glycol monobutyl ether (EB),ethylene glycol diethyl ether (EGDE) or other suitable internalstandard, d
35、iethylene glycol monobutyl ether (DB), and 2,2,4-trimethylepntane-1,3-diol monoisobutyrate (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.D6886 1229.2 Transfer approximately 100
36、 L of the stock mixture to aseptum-capped vial containing 10 mL of THF or methanol andmix the contents (Note 5). This solution will contain each ofthe known analytes at a concentration of approximately 2mg/mL.NOTE 5The solvents EG, PG, EB, DB TX are widely used in themanufacture of waterborne air-dr
37、y coatings and may be expected as highlyprobable components of these coatings.9.3 Chromatograph the solution in 9.2 by injecting 1 L intothe PMPS column using the chromatographic conditions givenin 6.2. Calculate the relative response factors for each of theanalytes relative to the EGDE or other sui
38、table internalstandard using the relationship:RF 5AA * MIAI * MA(3)where:RF = relative response factor,AA = area of analyte,MI = weight of internal standard (from 9.1),AI = area of internal standard, andMA = weight of analyte (from 9.1).10. Paint Analysis10.1 Analysis of Air-dry Solvent-borne and Wa
39、terborneCoatings by GC/FID or GC/MS:10.1.1 Prepare duplicate samples by pipetting 10 mL ofmethanol (waterborne coatings) or THF (solventborne coat-ings) into a vial containing 3 to5gofceramic beads and closewith a fluorcarbon-faced septum cap. Using a dedicated glasssyringe (25 or 50 microliter capa
40、city), add 10 L of EGDE orother internal standard and weigh to at least 0.1 mg. ThisTABLE 1 Standard FID Instrument ConditionsInstrument Conditions FID GC/MSDetector Flame ionization 70 eV electron impact massspectrometerColumns Primary column:30 by 0.25 mm5 % phenyl/95 % methylsiloxane (PMPS),A1.0
41、m film thicknessPrimary column:30 by 0.25 mm% phenyl/95 % methylsiloxane (PMPS),A1.0 m film thicknessConfirmatory Columns:30 by 0.25 mmpolydimethylsiloxane (PDMS),0.25 m film thickness;30 by 0.25 mmCarbowax (CW),0.25 m film thickness.Confirmatory Columns:30 by 0.25 mmpolydimethylsiloxane (PDMS),0.25
42、 m film thickness;30 by 0.25 mmCarbowax (CW),0.25 m film thickness.Carrier Gas Helium HeliumFlow Rate 1.0 mL per min,constant flow(24.9 cm/s at 40)1.0 mL per min,constant flow(24.9 cm/s at 40)Split Ratio 50 to 1 50 to 1Temperatures, C,Primary ColumnInlet 260 260Detector 270 270Initial 50 for 4 min 5
43、0 for 4 minRate 20 per min to 250,hold 6 min (total run time = 20 min)20 per min to 250,hold 6 min (total run time = 20 min)Temperatures, C,Confirmatory ColumnsInlet 260 260Detector 270 270Initial 40 for 4 min 40 for 4 minRate 10 per min to 250, hold 25min 10 per min to 250, hold 25minSource 230Quad
44、rupole 230Transfer Line 260Scanning Parameters Mass 29400 amuASome coatings may contain high-boiling components which elute from the GC capillary column after the specified run time of 20 minutes. It is advisable, therefore,to bake out the column in these cases. The column designated as PMPS is comm
45、ercially available from several vendors by the following designations: DB-5, SPB-5, HP-5,AT-5, CP Sil 8CB, RTx-5, BP-5. The column designated as PDMS is available by th designations DB-1, SPB-1, HP-1, AT-1, CP Sil 5 CB, Rtx-1. The column designatedas Carbowax is available by the designations Supelco
46、wax 10, DB-Wax, HP-Wax, AT-Wax, CP-Wax 52 CB, Rtx-Wax, BP-20.D6886 123solution must be analyzed by GC to determine if there arepeaks that result from it rather than from the paint sample thatis prepared in 10.1.2.10.1.2 Pipette 10 mLof methanol or THF into a 20 or 40 mLvial containing 3 to 5 g ceram
47、ic beads and close with afluorocarbon-faced septum cap. Using a disposable 1 mLsyringe, add approximately 0.6 to 0.8 g of the well-mixed paintthrough the septum cap and weigh to 0.1 mg (Note 6). Usingthe dedicated syringe, add 10 microliters of pure EGDE (orother internal standard) through the septu
48、m and weigh theamount added to at least 0.1 mg. Mix the contents vigorouslyby shaking for 1 min. Let the vial stand to permit pigments, ifany, 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 at
49、tached for paint transfer. The mass of the paint may bedetermined by either the difference in the weight of the filled and emptysyringe or by the difference in the weight of the vial before and afteradding paint.10.1.3 Chromatograph the solution in 10.1.2 by injecting 1L into the PMPS capillary column using the standard condi-tions described in 6.2.Adjust the split ratio to give well-definedchromatographic peaks. Identify the volatile compounds whichelute over a 20 minute run time. An internal marker, methylpal
