1、Designation: D4443 12Standard 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 D4443; the number immediately following the designation indicates th
2、e 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. Scope*1.1 This test method is suitable for determining the
3、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 standard does not purport
4、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 given in Section 9
5、and Note 13.NOTE 1This standard is equivalent to ISO 6401.2. Referenced Documents2.1 ISO Standard:ISO 6401 PlasticsHomopolymer and Copolymer Resinsof Vinyl ChlorideDetermination of Residual VinylChloride MonomerGas Chromatographic Method22.2 OSHA Standard:29 CFR 1919.1017 Vinyl Chloride33. Terminolo
6、gy3.1 Abbreviations:3.1.1 DMAcN,N-dimethylacetamide.3.1.2 VCMVinyl chloride monomer.4. Summary of Test Method4.1 Samples 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
7、 Aliquots of headspace gas are injected into a gaschromatograph and the vinyl chloride monomer is separated.The response 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 st
8、andards, (b) standard solutionscontaining known amounts of vinyl chloride monomer, or (c) amethod of standard addition.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 hum
9、ancarcinogen. Threshold toxicity value has not been established.5.3 Plastic manufacturers, food packagers, governmentagencies, 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
10、 iden-tical conditions to determine the absence of interferences at thevinyl chloride monomer gas chromatography (GC) 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
11、 either a flameionization detector (FID), a photo ionization detector (PID), ora Hall electroconductivity detector (HED), 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 b
12、e performed manually (that is, bysyringe injection), then the following equipment will also be needed:(1) Constant-temperature bath or oven capable of maintaining a1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on A
13、nalytical Methods.Current edition approved Oct. 1, 2012. Published November 2012. Originallyapproved in 1984. Last previous edition approved in 2007 as D4443 07. DOI:10.1520/D4443-12.2Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www
14、.ansi.org.3Available from Superintendent of Documents, US Government Printing Office,Washington, DC 20402.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1temperature of
15、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.7.2 Chromatographic Column, 3 % OV-101 on 80/1004,5mesh Chromosorb WHP4,5,18-in. (3.2-mm) outside diameterby 2 ft (0.6 m), stain
16、less steel connected through18-in. “tee” to0.19 % picric acid on 80/100 mesh Carbopack C4,5,18-in.outside diameter by 8 ft (2.4 m), stainless steel.NOTE 3Any column packing that will resolve VCM from interfer-ences and elute VCM in a reasonable length of time (1 to 5 min) issatisfactory. For example
17、, a 3-ft (0.9-m) by18-in. (3.2-mm) outsidediameter column containing 0.19 % picric acid on 80/100 mesh Car-bopack C can replace the recommended 3 % OV 101 column. Settingsrecommended in 11.3.1 may have to be modified to suit the packingmaterial being used.NOTE 4The VCM peak must be kept on scale to
18、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 low-VCMsamples. The other channel is set at a lower sensitivity to keep t
19、he 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 sensitiv-ity of this test method is best realized when the detector(usually operated at the maximum
20、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 Spectrum Scientific Model 1021A filter/amplifier5,6canfulfill these require
21、ments. 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.7.7 Statistical Programmable Calculator.NOTE 6A programmable calculator i
22、s 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 Cylinders, vinyl chloride monomer in nitrogenat 1 and 10 ppm by volume.8.3
23、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 room temperature to remove chromato-graphic interferences.9. Hazards9.1
24、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-dimethylacetamide is a teratogen. The use of aproperly functioning hood and septum-seale
25、d sample contain-ers are recommended.9.1.2 Avoid all contact with heated parts of the gaschromatograph, hot syringes, and sample bottles. Handle allelectrical connections with care.9.1.3 Once heated, sample vials are under pressure. Afteranalysis, relieve the pressure with a hypodermic syringe needl
26、evented 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 analysis. Dissolvedpolymer samples must be kept in septum-sealed vials or bottles
27、until 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 analyses are performed manually, alter theoperating procedures as required by the
28、 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.11.2 Set the flow of detector gases as follows:Detector Gas FlowFID Hydroge
29、n 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 columns are used, or when high-boiling solvents andlate-eluting materials are
30、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 elutes can consid-erably shorten analysis time. After backflushing, allow adequa
31、te 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.4The sole source of supply of column packing known to the committee at thistime is Supelco, Inc., P.O. Box 628, 146 S. Water St., Bellefon
32、te, PA 16823.5If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.6The sole source of supply of the apparatus known to
33、 the committee at this timeis Spectrum Scientific Corp., 2401 Ogletown Rd., Newark, DE 19711.D4443 12211.3.7 Filter/AmplifierAdjust as needed to remove highfrequency noise and to provide adequate amplification of VCMsignal. Typical settings: filter 0.05 Hz and amplifier 2.12. Calibration by Standard
34、 AdditionNOTE 11The gas chromatograph is calibrated using either procedure:(1) VCM in nitrogen gas standards and a previously determined partitioncoefficient for VCM between DMAc and headspace, (2) VCM solutionstandards, or (3) a method of standard addition of VCM to polymersolutions. Procedure (3)
35、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. In hood, prepare VCM stocksolution
36、 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 solution by withdraw-ing aliquots th
37、rough 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. Ifrefrigerated, these working standards are stable for severalweeks. Multiple septum punc
38、tures shorten the working life ofstandards.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 solutions preparedas described in Section 1
39、3. 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 film and bottle samples into small (;
40、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 and seal immediately with cap andseptum
41、. 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 stirring bar to the vials and effect solu
42、tionin 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 plantsand PVC fabricating plants. Therefo
43、re, 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 of the analysis.13.4 After solution is
44、 attained (5 h), spike vialsaccordingly, using syringe through thick portion of septum:Vials 1 and 2, no spike; Vials 3 and 4, Lof 1 to 5 ppm VCMin DMAc standard (see 11.1) ( L should give approximatelydouble the GC response for VCM as in the unknown); Vials 5and 6, 2 L of 1 to 5 ppm VCM standard; a
45、nd Vials 7 and 8,3 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 gas chromato-graph in the following sequence: so
46、lvent 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 negateresults.NOTE 15Experience with the method
47、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 towithdrawing 1.0-mL headspace sample for injection. Wear gloves forprotect
48、ion.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 3 or less to +3 or more.The units of they-axis should be from 0 to a positive value at least as large asthe net average response value for Vials 7 and
49、 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 straightline 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 the
