ASTM D6438-2005 Standard Test Method for Acetone Methyl Acetate and Parachlorobenzotrifluoride Content of Paints and Coatings by Solid Phase Microextraction-Gas Chromatography《用固相微.pdf

1、Designation: D 6438 05Standard Test Method forAcetone, Methyl Acetate, and ParachlorobenzotrifluorideContent of Paints, and Coatings by Solid PhaseMicroextraction-Gas Chromatography1This standard is issued under the fixed designation D 6438; the number immediately following the designation indicates

2、 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is for the determination of a

3、cetone,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, and urethane solv

4、ent-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 it suitable for

5、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 are included in

6、 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 prior to use.2

7、. Referenced Documents2.1 ASTM Standards:2D 3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD 6133 Test Method for Acetone Content,p-Chlorobenzotrifluoride, Methyl Acetate or t-Butyl AcetateContent of Solventborne and Waterborne Paints, Coatings,Resins, and Raw Materials by Dir

8、ect Injection into A GasChromatographE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3. Terminology3.1 Abbreviations:PCBTF parachlorobenzotrifluoride,(4-chlorobenzotrifluoride)MCBTF metachlorobenzotrifluoride(3-chlorobenzotri

9、fluoride)SPME solid phase microextractionVOC volatile organic compoundPEG/DVB polyethylene glycol/divinylbenzeneFID flame ionization detectorMS mass selective or mass spectralSIM selected ion monitoringGC gas chromatographSr repeatability standard deviationsSR reproducibility standard deviationsr re

10、peatability, 95 % confidence limitR reproducibility, 95 % confidence limit4. Summary of Test Method4.1 A suitable aliquot of whole solvent-borne paint isinternally standardized and diluted with dioctyl phthalate. Theheadspace of this solution is sampled with an SPME fiber,which is then thermally des

11、orbed 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 Use5.1 In order to calculate the volatile organic content (VOC)of paints cont

12、aining 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. Eachanalyte is measured with respect to a unique internal standard.1This test met

13、hod 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 July 1, 2005. Published July 2005. Originally approvedin 19

14、99. Last previous edition approved in 1999 as D 6438 99.2For 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 Document Summary page onthe ASTM website.1Copy

15、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 standar

16、d pairs behave very nearly as single solventswith respect to evaporation rate and adsorption rate 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 abilit

17、y of an analyst to weigh a paint sample and internalstandard, corresponding to the analyte of interest, 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 syst

18、em isnever compromised.6. Apparatus6.1 Manual SPME Holder,3fitted with partially crosslinkedpolyethylene 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. Temper

19、ature programming capability is desirable, butisothermal operations may be utilized.6.2.1 For FID instrument conditions, see Table 1.6.2.2 Inlet Liner, 0.75-mm should be placed in the injectionport.36.2.3 IntegratorAny electronic integrator that can accu-rately quantify a gas chromatographic peak ar

20、ea is acceptable.6.3 Gas Chromatograph, Mass Selective (MS) DetectionAny capillary gas chromatograph 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 instrum

21、ent conditions, see Table 2.6.3.2 Inlet liner, 0.75-mm, should be placed in the injectionport.36.3.3 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 conditionedaccordin

22、g to the manufacturers recommendation. The col-umns may then be used indefinitely without further 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 us

23、e.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. 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

24、available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently 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

25、, 99.9 % isotopic purity (see Note 2).8.5 Parachlorobenzotrifluoride, technical grade, 99+ % (seeNote 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 2

26、Methyl acetate-d3 was prepared by the acid-catalyzed reac-tion of methanol with acetic-d3 acid, 99.9 % isotopic purity.3The 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 alterna

27、tive suppliers, please provide this informa-tion to ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee,1which you mayattend.4Reagent Chemicals American Chemical Society, Specifications, AmericanChemical Society, Washin

28、gton, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, 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

29、 Instrument ConditionsDetector: Flame ionizationColumn: 60 m 3 0.25 mm 100 % polyethylene glycol, 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 3

30、0 per minute to 100, hold 10 minRate 2 30 per minute to 240, hold 2 minAIf the fiber desorption is carried out longer than 5 or 6 s, the acetone peaksexhibit tailing.A5 to 6s desorption time transfers 98 to 99 % of the analytes to thecapillary column. The fiber may be cleaned by inserting it into th

31、e GC inlet for 15s after analytes of interest have eluted.TABLE 2 MS Instrument ConditionsDetector: 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

32、% phenyl/95 % methylpolydimethylsiloxaneCarrier Gas: HeliumFlow Rate: 1.0 mL per minute (20 cm 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

33、fiber desorption is carried out longer than 5 or 6 s, the acetone peaksexhibit tailing.A5 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.D6438052NOTE 3Parachl

34、orobenzotrifluoride contained 0.5 % of the meta iso-mer and 0.1 % of the ortho isomer.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-mLdioct

35、yl phthalate into a 22 or 40-mLvial andseal with a septum cap.9.2 Using dedicated 250-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.An

36、y solvent adhering to the outside of the septum cap aftermaking the transfer should be 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 t

37、o 0.1 mg.9.3 Manually shake the vial for 15 s to mix the contents andthen let the vial 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 SPM

38、E fiber for 60 s.9.6 Desorb the SPME fiber for 5 to6sintheinjection portof the gas chromatograph 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 t

39、he GC/FID procedure measure the peak areasof the three analytes and three standards by 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 a

40、cetate-d3, 11.06; methylacetate, 11.22: MCBTF, 22.33; PCBTF, 23.53.9.9 If using the GC/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 valu

41、es should agree within 1 % of each other.10. Procedure10.1 Using a disposable 1-mL syringe, weigh 0.5 to 1.0 g ofwell mixed paint (see Note 6 and Practice D 3925) into aseptum-capped vial containing 6 mL of dioctyl phthalate. Thepaint should drop directly into the dioctyl phthalate. Carry outthe sam

42、e procedures as described in 9.3-9.7.NOTE 6Since acetone and methyl acetate are extremely 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 pain

43、t sample and if interfering peaks arepresent at the retention times corresponding to the 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-c

44、apped vial containing 6 mL dioctylphthalate, weigh 0.5 to 1.0 g of paint sample to 0.1 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 eq

45、uations:RF 5AA 3 MIAI 3 MA(1)and% Analyte 5AA 3 MI 3 100AI 3 RF 3 MC(2)where:RF = response 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

46、amounts such that the relative peak areas ofthe analyte and its internal standard chromatographic 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 conten

47、tusing Test Method D 6133.11. Precision and Bias11.1 PrecisionA round robin was conducted 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 mas

48、s spectral (MS) detection tomeasure analyte amounts.11.2 Six commercial solvent-borne coatings 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

49、 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 values, repeatability standard deviations(Sr), and reproducibility standard deviations (SR) are given foreach coating and exempt solvent in Table 4 and Table 5.TABLE 3 Approximate Retention Times and Masses of Analytesand Internal St