ASTM D4443-1995(2002) Standard Test Method for Determining Residual Vinyl Chloride Monomer Content in PPB Range in Vinyl Chloride Homo- and Co-Polymers by Headspace Gas Chromatogra.pdf

1、Designation: D 4443 95 (Reapproved 2002)Standard Test Method forDetermining Residual Vinyl Chloride Monomer Content inPPB Range in Vinyl Chloride Homo- and Co-Polymers byHeadspace Gas Chromatography1This standard is issued under the fixed designation D 4443; the number immediately following the desi

2、gnation 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is suitable

3、for determining the residualvinyl chloride monomer (RVM) content of homopolymer andcopolymers of vinyl chloride down to a level of ;5 ppb.1.2 This test method is applicable to any polymer form, suchas resin, compound, film, bottle wall, etc. that can be dissolvedin a suitable solvent.1.3 This standa

4、rd 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. Specific hazardstatements are

5、 given in Section 9 and Note 13.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Document2.1 OSHA Standard:29 CFR 1919.1017Vinyl Chloride23. Terminology3.1 Abbreviations:Abbreviations:3.1.1 DMAcN,N-dimethylacetamide.3.1.2 VCMVinyl chloride monomer.4. Summary of Test Method4.1 Sampl

6、es of vinyl chloride-containing polymers are dis-solved in a suitable solvent in a closed system.4.2 The polymer solution and headspace are equilibrated atan elevated temperature.4.3 Aliquots of headspace gas are injected into a gaschromatograph and the vinyl chloride monomer is separated.The respon

7、se of vinyl chloride monomer is determined by theuse of one of several suggested detectors.4.4 Calibration is accomplished using either (a) vinyl chlo-ride monomer in nitrogen gas standards, (b) standard solutionscontaining known amounts of vinyl chloride monomer, or (c) amethod of standard addition

8、.5. Significance and Use5.1 Vinyl chloride-containing polymers are widely used topackage a variety of materials, including foods.5.2 Vinyl chloride monomer has been shown to be a humancarcinogen. Threshold toxicity value has not been established.5.3 Plastic manufacturers, food packagers, governmenta

9、gencies, etc. have a need to know the residual vinyl chloridemonomer content of vinyl chloride-containing polymers.6. Interferences6.1 N,N- dimethylacetamide should be analyzed under iden-tical conditions to determine the absence of interferences at thevinyl chloride monomer gas chromatography (GC)

10、retentiontime.6.2 Other solvents, monomers, or compounding aids maycause interference at the vinyl chloride monomer GC retentiontime.7. Apparatus7.1 Gas Chromatography, equipped with either a flameionization detector (FID), a photo ionization detector (PID), ora Hall electroconductivity detector (HE

11、D), backflushing valve,and either automatic capability or manual sampling (Note 2)and ability to analyze the headspace vapors contained in asealed vial.NOTE 2If the analyses are to be performed manually (that is, bysyringe injection), then the following equipment will also be needed:(1) Constant-tem

12、perature bath or oven capable of maintaining atemperature of 90 6 1C.(2) Gas-tight GC syringes for sampling and injection.(3) Sample bottles with fluoropolymer faces septa and caps (sizeoptional).(4) Gloves for handling hot syringes.1This test method is under the jurisdiction of ASTM Committee D20 o

13、n Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods(Section D20.70.03).Current edition approved October 10, 1995. Published December 1995. Origi-nally published as D4443 84. Last previous edition D 4443 84 (1989)e1.This revision includes the addition of an ISO equ

14、ivalency statement and akeywords section.2Available from Superintendent of Documents, US Government Printing Office,Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 Chromatographic Column, 3 % OV-101 on 80/100

15、3mesh Chromosorb WHP3,18-in. (3.2-mm) outside diameter by2 ft (0.6 m), stainless steel connected through18-in. “tee” to0.19 % picric acid on 80/100 mesh Carbopack C3,18-in.outside diameter by 8 ft (2.4 m), stainless steel.NOTE 3Any column packing that will resolve VCM from interfer-ences and elute V

16、CM in a reasonable length of time (1 to 5 min) issatisfactory. For example, a 3-ft (0.9-m) by18-in. (3.2-mm) outsidediameter column containing 0.19 % picric acid on 80/100 mesh Carbo-pack C can replace the recommended 3 % OV 101 column. Settingsrecommended in 11.3.1 may have to be modified to suit t

17、he packingmaterial being used.NOTE 4The VCM peak must be kept on scale to manually measurethe correct peak area or peak height. One method of achieving this withoutundue operator attention is to use a dual-channel recorder. One channel isset at a high sensitivity to obtain measurable small peaks for

18、 low-VCMsamples. The other channel is set at a lower sensitivity to keep the largerpeaks from high-VCM samples on scale. Most instruments will calculatepeak height (or area) even if the peak goes off the scale on the recorder.7.3 Detector Output Filter/AmplifierThe extreme sensi-tivity of this test

19、method is best realized when the detector(usually operated at the maximum sensitivity) output is (1)filtered to remove the high-frequency noise and (2) amplified togive a visible or measurable signal. The filter/amplifier isconnected in series between the detector and the recorder/computer.NOTE 5A S

20、pectrum Scientific Model 1021A filter/amplifier4canfulfill these requirements. Other filter/amplifiers may be available that aresuitable.7.4 Sample Headspace Vials, glass, 23 mL, withfluoropolymer-lined septa and aluminum caps.7.5 Vial Sealer.7.6 Analytical Balance, capable of weighing to 60.001 g.7

21、.7 Statistical Programmable Calculator.NOTE 6A programmable calculator is not absolutely necessary, butcan save a considerable amount of time when large numbers of samplesare being analyzed.8. Reagents and Materials8.1 Vinyl Chloride Monomer (neat), pure, preferably insmall cylinder.8.2 Standard Cyl

22、inders, vinyl chloride monomer in nitrogenat 1 and 10 ppm by volume.8.3 Hydrogen Cylinder, prepurified gas.8.4 Nitrogen, oxygen-free.NOTE 7Helium may replace nitrogen as the carrier gas.8.5 Air, breathing or water-pumped.8.6 N,N-Dimethylacetamide (DMAc), sparged with nitrogengas for up to a week at

23、room temperature to remove chromato-graphic interferences.9. Hazards9.1 Safety Precautions:9.1.1 Vinyl chloride monomer is a carcinogen and exposureby inhalation or dermal contact, or both, is to be avoided. Referto OSHA Standard 29 CFR 1919.1017 for regulated levels ofexposure. N,N-dimethylacetamid

24、e is a teratogen. The use of aproperly functioning hood and septum-sealed sample contain-ers are recommended.9.1.2 Avoid all contact with heated parts of the gas chro-matograph, hot syringes, and sample bottles. Handle all elec-trical connections with care.9.1.3 Once heated, sample vials are under p

25、ressure. Afteranalysis, relieve the pressure with a hypodermic syringe needlevented into a charcoal slug or vent tube leading to a hoodbefore removing vials from the water bath.10. Sampling and Storage10.1 Keep all polymer samples in tightly sealed jars ortightly wrapped aluminum foil prior to analy

26、sis. Dissolvedpolymer samples must be kept in septum-sealed vials or bottlesuntil analyzed. Polymer solutions stored longer than 24 hshould be maintained under refrigeration.11. Preparation of Gas ChromatographNOTE 8All conditions in this section refer to the Perkin-ElmerHeadspace Analyzer. If analy

27、ses are performed manually, alter theoperating procedures as required by the instrumentation.11.1 Install the chromatographic column and conditionovernight at 100C, using normal carrier flow. Do not connectthe exit end of the column to the detector or turn on detectorgases during column conditioning

28、.11.2 Set the flow of detector gases as follows:Detector Gas FlowFID Hydrogen 30 to 40 cm3/minAir 300 to 400 cm3/minPID Not requiredHED Hydrogen 30 cm3/min11.3 Set other parameters as follows:11.3.1 Oven Temperature50 to 60C.NOTE 9Higher oven temperatures may be required when otherchromatographic co

29、lumns are used, or when high-boiling solvents andlate-eluting materials are being driven from the column.11.3.2 Dosing Needle150C.11.3.3 Injection Block Temperature200C.11.3.4 Constant-Temperature Bath90 6 1.0C.11.3.5 Carrier-Gas Flow Rate30 cm3/min.NOTE 10Backflushing the carrier gas after VCM elut

30、es can consid-erably shorten analysis time. After backflushing, allow adequate time forchromatographic conditions to stabilize before making another injection.11.3.6 Detector Temperature:11.3.6.1 FID250C.11.3.6.2 PID150C.11.3.6.3 HED880C.11.3.7 Filter/AmplifierAdjust as needed to remove highfrequenc

31、y noise and to provide adequate amplification of VCMsignal. Typical settings: filter 0.05 Hz and amplifier 23.12. Calibration by Standard AdditionNOTE 11The gas chromatograph is calibrated using either procedure:(1) VCM in nitrogen gas standards and a previously determined partition3Column packing i

32、s available from Supelco, Inc., P.O. Box 628, 146 S. WaterSt., Bellefonte, PA 16823.4Available from Spectrum Scientific Corp., 2401 Ogletown Rd., Newark, DE19711.D 4443 95 (2002)2coefficient for VCM between DMAc and headspace, (2) VCM solutionstandards, or (3) a method of standard addition of VCM to

33、 polymersolutions. Procedure (3) is preferred to correct for any contribution thepolymer makes to partitioning of VCM. Therefore, only procedure (3)isdescribed.12.1 Accurately weigh headspace vial, cap, and septumusing an analytical balance. Add 20 mL DMAc to weighedvial. Cap loosely, and reweigh. I

34、n hood, prepare VCM stocksolution in this vial by quickly uncapping vial and adding 0.4to 2 g liquid VCM from inverted freezer-cooled cylinder ofVCM. Immediately cap vial tightly and mix well by shaking.Reweigh and calculate VCM concentration by weight (ca20 000 to 80 000 ppm). Dilute this stock sol

35、ution by withdraw-ing aliquots through the septum with a syringe and injectinginto weighed, sealed vials of DMAc. Reweigh, and calculateVCM concentration (ca 50 ppm). This solution is similarlydiluted to yield a solution containing 1 to 5 ppm. If refriger-ated, these working standards are stable for

36、 several weeks.Multiple septum punctures shorten the working life of stan-dards.NOTE 12Other methods of introducing VCM into the DMAc may besatisfactory. These should be shown to be accurate and safe.12.2 Add known volumes (microlitres) of the 1 to 5-ppmVCM in the DMAc standard to the polymer soluti

37、ons preparedas described in Section 13. Analyze solutions along withsolvent blanks and the unknown, unspiked polymer solutions.13. Procedure for Sample Analysis13.1 Prepare two solvent blanks by adding 10.00 mL ofDMAc to each of the two vials. Seal immediately with cap andseptum.13.2 Cut up polymer

38、film and bottle samples into small (;5by 5 mm) pieces. Use powder and pellet samples as received.13.3 Prepare 8 vials, each containing the same weight,60.01 g, of polymer (1.00 to 4.00 g depending on previouslydetermined solubility or desired sensitivity, or both). Add 10.00mL of DMAc to each vial a

39、nd seal immediately with cap andseptum. Begin vigorously shaking vials at once to facilitatedissolution. Immerse vials in the constant-temperature bath (906 1C) until complete solution is effected. Vigorously shakevials occasionally to aid solution. Alternatively, (1) immedi-ately add a magnetic sti

40、rring bar to the vials and effect solutionin an 85 to 95C water bath on a stirring-type hot plate or (2)place vials on/in a reciprocating shaker and heat with a heatlamp.NOTE 13Precaution: Vinyl chloride monomer may be present in theatmosphere of laboratories located in or near PVC manufacturing pla

41、ntsand PVC fabricating plants. Therefore, it may be necessary to prepare thesealed vials of solvent blanks and sample mixtures inside a nitrogen-flushed glove box or glove bag to avoid contamination by air-born VCM.Once sealed, the vials can be returned to the laboratory atmosphere for theremainder

42、of the analysis.13.4 After solution is attained (5 h), spike vials accord-ingly, using syringe through thick portion of septum: Vials 1and 2, no spike; Vials 3 and 4, 3 L of 1 to 5 ppm VCM inDMAc standard (see 11.1) (3 L should give approximatelydouble the GC response for VCM as in the unknown); Via

43、ls 5and 6, 2 3 L of 1 to 5 ppm VCM standard; and Vials 7 and 8,3 3 L of 1 to 5 ppm VCM standard.13.5 Shake all vials to ensure homogeneity. Heat vials inconstant-temperature bath (90 6 1C) for 1 h.13.6 Adjust instrument injection time to inject maximumamount of headspace gas from each vial into the

44、gas chromato-graph in the following sequence: solvent blank, 8, 6, 4, 2, 1, 3,5, 7 solvent blank.NOTE 14It may be useful to measure vial pressure after analysis butbefore removing the vial from the bath. This ensures that the vial wascorrectly pressurized and no leaks occurred, either of which will

45、negateresults.NOTE 15Experience with the method and system or development, orboth, of response factors for one type of polymer may permit a reductionin the number of analyses of spiked unknowns during a determination.NOTE 16For manual injections, heat syringe to 90C prior to with-drawing 1.0-mL head

46、space sample for injection. Wear gloves for protec-tion.13.7 Prior to plotting data points, construct two perpendicu-lar axes on linear graph paper. The units of the x-axis should bein terms of X, from 33 or less to +33 or more. The units ofthe y-axis should be from 0 to a positive value at least as

47、 largeas the net average response value for Vials 7 and 8.13.8 Plot the net VCM response (average sample responsefor duplicate vials minus average blank response) for each vialpair on the y-axis versus the weight of VCM that was added toeach member of the pair on the x-axis. Draw the best straightli

48、ne through the four points and extrapolate the line to intersectthe x-axis. The distance from this point of intersection to thePoint X = 0 on the x-axis is a measure of the VCM content ofthe sample. See Fig. 1.NOTE 17A computer program can be used to plot and extrapolate thedata.14. Calculation14.1

49、Calculate the VCM content in the unknown by deter-mining the nanograms VCM obtained in the unknown (fromthe plot or computer) and dividing by the weight of polymer inthe vial. Report findings in parts per billion (nanograms pergram).15. Report15.1 Report the VCM content in parts per billion as calcu-lated in 14.1.FIG. 1 Standard Additions Extrapolation PlotD 4443 95 (2002)316. Precision and Bias516.1 The following values were determined for the coeffi-cients of variation of this test method on the basis of aninterlaboratory