1、Designation: D6438 05 (Reapproved 2010)Standard Test Method forAcetone, Methyl Acetate, and ParachlorobenzotrifluorideContent of Paints, and Coatings by Solid PhaseMicroextraction-Gas Chromatography1This standard is issued under the fixed designation D6438; the number immediately following the desig
2、nation indicates the year oforiginal adoption or, 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 det
3、ermination of acetone,methyl acetate, or parachlorobenzotrifluoride (PCBTF), orcombination of any of the three, in paints and coatings, by solidphase microextraction (SPME) headspace sampling, and sub-sequent injection into a gas chromatograph. It has beenevaluated for cellulose nitrate, acrylic, an
4、d urethane solvent-borne systems. The established working range of this testmethod is: acetone, 28 to 90 %; methyl acetate, 12 to 22 %;parachlorobenzotrifluoride, 10 to 17 %. There is no reason tobelieve that it will not work outside these ranges. A minormodification of this test method would make i
5、t suitable for theanalysis of the same analytes in water-borne coatings (see Note1).NOTE 1Water-borne paints are internally standardized and dilutedwith water followed by addition of solid sodium chloride.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement
6、are included in thisstandard.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 safety and health practices and determine the applica-bility of regulatory limitations
7、 prior to use.2. Referenced Documents2.1 ASTM Standards:2D3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD6133 Test Method for Acetone, p-Chlorobenzotrifluoride,MethylAcetate or t-ButylAcetate Content of Solventborneand Waterborne Paints, Coatings, Resins, and Raw Mate-rials b
8、y Direct Injection Into a Gas ChromatographE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals33. Terminology3.1 Abbreviations:3.1.1 PCBTFparachlorobenzotrifluoride,(4-chlorobenzotrifluoride)3.1.2 MCBTFmetachlorobenzotrifluoride(
9、3-chlorobenzotrifluoride)3.1.3 SPMEsolid phase microextraction3.1.4 VOCvolatile organic compound3.1.5 PEG/DVBpolyethylene glycol/divinylbenzene3.1.6 FIDflame ionization detector3.1.7 MSmass selective or mass spectral3.1.8 SIMselected ion monitoring3.1.9 GCgas chromatograph3.1.10 Srrepeatability stan
10、dard deviations3.1.11 SRreproducibility standard deviations3.1.12 rrepeatability, 95 % confidence limit3.1.13 Rreproducibility, 95 % confidence limit4. Summary of Test Method4.1 A suitable aliquot of whole solvent-borne paint isinternally standardized and diluted with dioctyl phthalate. Theheadspace
11、 of this solution is sampled with an SPME fiber,which is then thermally desorbed in the injection port of a gaschromatograph onto a suitable capillary column. Either a flameionization or mass specific detector may be used to measurepeak areas of analytes and internal standards.5. Significance and Us
12、e5.1 In order to calculate the volatile organic content (VOC)of paints containing EPA exempt solvents, it is necessary toknow the acetone, methyl acetate, or parachlorobenzotrifluo-ride content. This gas chromatographic test method provides asimple and direct way for measuring these solvents. Each1T
13、his 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 Materials.Current edition approved Dec. 1, 2010. Published December 2010. Original
14、lyapproved in 1999. Last previous edition approved in 2005 as D6438 99 (2005).DOI: 10.1520/D6438-05R10.2For 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
15、 Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.analyte is measured with respect to a unique int
16、ernal standard.For acetone, the internal standard used is acetone-d6, formethyl acetate it is methyl acetate-d3, and for PCBTF it ismetachlorobenzotrifluoride (MCBTF). These unique analyte/internal standard pairs behave very nearly as single solventswith respect to evaporation rate and adsorption ra
17、te onto acoated silica fiber (SPME) but are separable on a gas chro-matograph (GC) capillary column. The only critical analyticaltechnique required for successfully performing this test methodis the ability of an analyst to weigh a paint sample and internalstandard, corresponding to the analyte of i
18、nterest, into a septumcapped vial. After weighing, solvent evaporation has no effecton the final value of the determination. Since whole paint is notinjected into the gas chromatograph, the analytical system isnever compromised.6. Apparatus6.1 Manual SPME Holder,4fitted with partially crosslinkedpol
19、yethylene glycol/divinylbenzene (PEG/DVB) fiber assem-bly, 65m film thickness.6.2 Gas Chromatograph, FID DetectionAny capillary gaschromatograph equipped with a flame ionization detector maybe used. Temperature programming capability is desirable, butisothermal operations may be utilized.6.2.1 For F
20、ID instrument conditions, see Table 1.6.2.2 Inlet Liner, 0.75-mm should be placed in the injectionport.46.2.3 IntegratorAny electronic integrator that can accu-rately quantify a gas chromatographic peak area is acceptable.6.3 Gas Chromatograph, Mass Selective (MS) DetectionAny capillary gas chromato
21、graph equipped with a mass selec-tive detector may be used. The detector must be capable ofmeasuring in the selected ion monitoring (SIM) mode at dwelltimes of 100 milliseconds or less.6.3.1 For MS instrument conditions, see Table 2.6.3.2 Inlet liner, 0.75-mm, should be placed in the injectionport.4
22、6.3.3 The instrument should have a software data system toallow extraction and integration of the SIM ions.7. Column and Fiber Conditioning7.1 Either or both capillary columns should be conditionedaccording to the manufacturers recommendation. The col-umns may then be used indefinitely without furth
23、er condition-ing.7.2 The SPME fiber should be conditioned and used accord-ing to the manufacturers recommendation.7.3 The SPME fiber should be inserted into a 260 Cinjection port for 30 s prior to daily use.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all te
24、sts. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsuff
25、iciently high purity to permit its use without lessening theaccuracy of the determination.8.2 Carrier Gas, Helium of 99.995 % or higher purity.8.3 Acetone -d6, 99.9 % isotopic purity.8.4 Methyl Acetate -d3, 99.9 % isotopic purity (see Note 2).8.5 Parachlorobenzotrifluoride, technical grade, 99+ % (s
26、eeNote 3).8.6 Metachlorobenzotrifluoride, 97 %, (see Note 4).8.7 Dedicated Syringes, 250-L syringes, and DisposalSyringes, 1.0 mL.8.8 Septum Vials, 22 or 40 mL, with fluorocarbon-facedsilicone septa.NOTE 2Methyl acetate-d3 was prepared by the acid-catalyzed reac-tion of methanol with acetic-d3 acid,
27、 99.9 % isotopic purity.4The sole source of supply of the manual holder and fibers known to thecommittee at this time is Supelco Company, Supelco Park, Bellefonte, PA16823-0048. If you are aware of alternative suppliers, please provide this informa-tion to ASTM International Headquarters. Your comme
28、nts will receive carefulconsideration at a meeting of the responsible technical committee,1which you mayattend.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society
29、, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopia andNational Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 1 FID Instrument ConditionsDetector: Flame ionizationColumn: 60 m 3 0.25 mm 100 % polyethylene glyco
30、l, 0.5-mfilm thicknessCarrier Gas: HeliumFlow Rage: 1.0 mL per minute (20 cm per second)Split Ratio: 200 to 1Fiber desorption time: 5 to 6 sATemperature, CInlet 260Detector 270Initial 35 for 12 minRate 1 30 per minute to 100, hold 10 minRate 2 30 per minute to 240, hold 2 minAIf the fiber desorption
31、 is carried out longer than 5 or 6 s, the acetone peaksexhibit tailing.A 5 to 6s desorption time transfers 98 to 99 % of the analytes to thecapillary column. The fiber may be cleaned by inserting it into the GC inlet for 15s after analytes of interest have eluted.TABLE 2 MS Instrument ConditionsDete
32、ctor: Electron ionization or mass selectiveDetection Mode: Selected ion monitoring (SIM) of ions m/e 58, 64,74, 77, and 180Dwell Time: 100 milliseconds or lessSolvent Delay: 0.0 minColumn: 25 m 3 0.20 mm 5 % phenyl/95 % methylpolydimethylsiloxaneCarrier Gas: HeliumFlow Rate: 1.0 mL per minute (20 cm
33、 per second)Split Ratio: 200 to 1Fiber desorption time: 5 to 6 sATemperatures, CInlet 260Detector 280Initial 40 for 2 minRate 1 10 per minute to 90, hold 1 minRate 2 40 per minute to 240, hold 1 minAIf the fiber desorption is carried out longer than 5 or 6 s, the acetone peaksexhibit tailing.A 5 to
34、6s desorption time transfers 98 to 99 % of the analytes to thecapillary column. The fiber may be cleaned by inserting it into the GC inlet for 15s after analytes of interest have eluted.D6438 05 (2010)2NOTE 3Parachlorobenzotrifluoride contained 0.5 % of the meta iso-mer and 0.1 % of the ortho isomer
35、.NOTE 4The metachlorobenzotrifluoride standard was chromato-graphically analyzed on a 60meter 100 % polyethylene glycol column(see 6.2) and exhibited only a single peak.9. Preparation of Standards9.1 Place 6-mLdioctyl phthalate into a 22 or 40-mLvial andseal with a septum cap.9.2 Using dedicated 250
36、-L syringes, weigh approximately100 mg each of parachlorobenzotrifluoride and metachloroben-zotrifluoride to 0.1mg into the vial. Excess solvent should bewiped from the syringe needle prior to piercing the septum.Any solvent adhering to the outside of the septum cap aftermaking the transfer should b
37、e wiped off with tissue. Weigh theamounts of PCBTF and MCBTF to 0.1 mg. Repeat theprocedure by adding approximately 150 mg each of acetone,acetone-d6, methyl acetate, and methyl acetate-d3, and weigheach component to 0.1 mg.9.3 Manually shake the vial for 15 s to mix the contents andthen let the via
38、l stand at room temperature for 30 min.9.4 Remove the cap and wipe the septum to remove solventfrom the inner surface and reseal immediately, or replace theseptum with a new one.9.5 Sample the headspace with the SPME fiber for 60 s.9.6 Desorb the SPME fiber for 5 to6sintheinjection portof the gas ch
39、romatograph using either the conditions describedin 6.2 or 6.3.9.7 Clean the fiber by placing it in the GC injection port for15 s after the analytes of interest have passed through thecapillary column.9.8 If using the GC/FID procedure measure the peak areasof the three analytes and three standards b
40、y integration (SeeNote 5). Curve fitting software for measuring peak areas isadvantageous in some instances.NOTE 5The approximate retention times in minutes are as follows:acetone-d6, 10.35; acetone, 10.56; methyl acetate-d3, 11.06; methylacetate, 11.22: MCBTF, 22.33; PCBTF, 23.53.9.9 If using the G
41、C/MS procedure, measure the peak areasfor the extracted ions indicated in Table 3.9.10 Calculate response factors (RF) for acetone, methylacetate, and PCBTF according to the equation given in 10.4.The numerical values should agree within 1 % of each other.10. Procedure10.1 Using a disposable 1-mL sy
42、ringe, weigh 0.5 to 1.0 g ofwell mixed paint (see Note 6 and Practice D3925) into aseptum-capped vial containing 6 mL of dioctyl phthalate. Thepaint should drop directly into the dioctyl phthalate. Carry outthe same procedures as described in 9.3-9.7.NOTE 6Since acetone and methyl acetate are extrem
43、ely volatile, it isadvisable to split the initial paint sample to be tested into two or moresamples in suitable secondary containers.10.2 Determine which, if any, of the three exempt solventsare present in the paint sample and if interfering peaks arepresent at the retention times corresponding to t
44、he retentiontimes of the internal standards (see Note 7).NOTE 7The area of an interfering peak, if any, found in 10.2, may besubtracted from the area of the standard peak when carrying out 10.5.10.3 Into a septum-capped vial containing 6 mL dioctylphthalate, weigh 0.5 to 1.0 g of paint sample to 0.1
45、 mg. Add100 mg of each of the internal standards, corresponding to theanalytes found in 10.1. Carry out the same procedure asdescribed in 9.3-9.9.10.4 Calculate analyte concentrations according to the fol-lowing equations:RF 5AA 3 MIAI 3 MA(1)and% Analyte 5AA 3 MI 3 100AI 3 RF 3 MC(2)where:RF = resp
46、onse factor,AA = area of analyte,MI = mass of internal standard,AI = area of internal standard,MA = mass of analyte, andMC = mass of coating.10.5 Repeat the procedure given in 10.3 using paint andinternal standard amounts such that the relative peak areas ofthe analyte and its internal standard chro
47、matographic peakareas are approximately the same size. A duplicate injection ofthe same sample should give relative peak areas that agreewithin 1 % of each other.10.6 Samples may also be analyzed for acetone contentusing Test Method D6133.11. Precision and Bias11.1 PrecisionA round robin was conduct
48、ed involvingfive laboratories. All of the laboratories used the SPMEsampling technique. Three of the laboratories used flameionization (FID) detection to measure analyte amounts and twoof the laboratories used mass spectral (MS) detection tomeasure analyte amounts.11.2 Six commercial solvent-borne c
49、oatings were analyzed.Four of the coatings contained acetone and two of the samefour coatings contained both acetone and parachlorobenzotri-fluoride. Coatings containing methyl acetate were not yetavailable in the marketplace and were therefore prepared byadding known amounts of methyl acetate to different cellulosenitrate lacquers.11.3 Precision data was calculated separately for the threelaboratories using FID detection and the two laboratories usingMS detection and also for the combination of FID and MSdetection. Average value
