1、Designation: D4443 12D4443 13Standard 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 indi
2、cates 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. Scope*1.1 This test method is suitable for determin
3、ing the residual vinyl 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, such as resin, compound, film, bottle wall, etc. that can be dissolvedin a suitable solvent.1.3 This standard does no
4、t purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific hazard statements are given in S
5、ection 9 and Note 1310.NOTE 1This standard is equivalent to ISO 6401.2. Referenced Documents2.1 ISO Standard:ISO 6401 PlasticsHomopolymer and Copolymer Resins of Vinyl ChlorideDetermination of Residual Vinyl ChlorideMonomerGas Chromatographic Method22.2 OSHA Standard:29 CFR 1919.1017 Vinyl Chloride3
6、3. Terminology3.1 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 dissolved in a suitable solvent in a closed system.4.2 The polymer solution and headspace are equilibrated at an elevated tem
7、perature.4.3 Aliquots of headspace gas are injected into a gas chromatograph and the vinyl chloride monomer is separated. The responseof vinyl chloride monomer is determined by the use of one of several suggested detectors.4.4 Calibration is accomplished using either (a) vinyl chloride monomer in ni
8、trogen gas standards, (b) standard solutionscontaining known amounts of vinyl chloride monomer, or (c) a method of standard addition.5. Significance and Use5.1 Vinyl chloride-containing polymers are widely used to package a variety of materials, including foods.5.2 Vinyl chloride monomer has been sh
9、own to be a human carcinogen. Threshold toxicity value has not been established.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Oct. 1, 2012Nov. 1, 2013. Published No
10、vember 2012November 2013. Originally approved in 1984. Last previous edition approved in 20072012as D4443 07.D4443 12. DOI: 10.1520/D4443-12.10.1520/D4443-13.2 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.3 Available f
11、rom Superintendent of Documents, US Government Printing Office, Washington, DC 20402.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to a
12、dequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright AS
13、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Plastic manufacturers, food packagers, government agencies, etc. have a need to know the residual vinyl chloride monomercontent of vinyl chloride-containing polymers.6. Interferences6.1 N,N- dim
14、ethylacetamide should be analyzed under identical conditions to determine the absence of interferences at the vinylchloride monomer gas chromatography (GC) retention time.6.2 Other solvents, monomers, or compounding aids may cause interference at the vinyl chloride monomer GC retention time.7. Appar
15、atus7.1 Gas Chromatography, equipped with either a flame ionization detector (FID), a photo ionization detector (PID), or a Hallelectroconductivity detector (HED), backflushing valve, and either automatic capability or manual sampling (Note 2) and abilityto analyze the headspace vapors contained in
16、a sealed vial.NOTE 2If the analyses are to be performed manually (that is, by syringe injection), then the following equipment will also be needed:(1) Constant-temperature bath or oven capable of maintaining a temperature of 90 6 1C.(2) Gas-tight GC syringes for sampling and injection.(3) Sample bot
17、tles with fluoropolymer faces septa and caps (size optional).(4) Gloves for handling hot syringes.7.2 Chromatographic Column, 3 % OV-101 on 80/100, mesh Chromosorb WHP, 18-in. (3.2-mm) outside diameter by 2 ft (0.6m), stainless steel connected through 18-in. “tee” to 0.19 % picric acid on 80/100 mes
18、h Carbopack C, 18-in. outside diameter by8 ft (2.4 m), stainless steel.NOTE 3Any column packing that will resolve VCM from interferences and elute VCM in a reasonable length of time (1 to 5 min) is satisfactory.For example, a 3-ft (0.9-m) by 18-in. (3.2-mm) outside diameter column containing 0.19 %
19、picric acid on 80/100 mesh Carbopack C can replace therecommended 3 % OV 101 column. Settings recommended in 11.3.1 may have to be modified to suit the packing material being used.NOTE 4The VCM peak must be kept on scale to manually measure the correct peak area or peak height. One method of achievi
20、ng this without undueoperator attention is to use a dual-channel recorder. One channel is set at a high sensitivity to obtain measurable small peaks for low-VCM samples. Theother channel is set at a lower sensitivity to keep the larger peaks from high-VCM samples on scale. Most instruments will calc
21、ulate peak height (or area)even if the peak goes off the scale on the recorder.7.3 Detector Output Filter/AmplifierThe extreme sensitivity of this test method is best realized when the detector (usuallyoperated at the maximum sensitivity) output is (1) filtered to remove the high-frequency noise and
22、 (2) amplified to give a visibleor measurable signal. The filter/amplifier is connected in series between the detector and the recorder/computer.NOTE 5ASpectrum Scientific Model 1021Afilter/amplifier5,6 can fulfill these requirements. Other filter/amplifiers may be available that are suitable.7.4 Sa
23、mple Headspace Vials, glass, 23 mL, with fluoropolymer-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 6Aprogrammable calculator is not absolutely necessary, but can save a considerable amount of time
24、when large numbers of samples are beinganalyzed.8. Reagents and Materials8.1 Vinyl Chloride Monomer (neat), pure, preferably in small cylinder.8.2 Standard Cylinders, vinyl chloride monomer in nitrogen at 1 and 10 ppm by volume.8.3 Hydrogen Cylinder, prepurified gas.8.4 Nitrogen, oxygen-free.NOTE 4H
25、elium may replace nitrogen as the carrier gas.8.5 Air, breathing or water-pumped.8.6 N,N-Dimethylacetamide (DMAc), sparged with nitrogen gas for up to a week at room temperature to removechromatographic interferences.9. Hazards9.1 Safety Precautions:9.1.1 Vinyl chloride monomer is a carcinogen and e
26、xposure by inhalation or dermal contact, or both, is to be avoided. Referto OSHA Standard 29 CFR 1919.1017 for regulated levels of exposure. N,N-dimethylacetamide is a teratogen. The use of aproperly functioning hood and septum-sealed sample containers are recommended.9.1.2 Avoid all contact with he
27、ated parts of the gas chromatograph, hot syringes, and sample bottles. Handle all electricalconnections with care.D4443 1329.1.3 Once heated, sample vials are under pressure.After analysis, relieve the pressure with a hypodermic syringe needle ventedinto a charcoal slug or vent tube leading to a hoo
28、d before removing vials from the water bath.10. Sampling and Storage10.1 Keep all polymer samples in tightly sealed jars or tightly wrapped aluminum foil prior to analysis. Dissolved polymersamples must be kept in septum-sealed vials or bottles until analyzed. Polymer solutions stored longer than 24
29、 h should bemaintained under refrigeration.11. Preparation of Gas ChromatographNOTE 5All conditions in this section refer to the Perkin-Elmer Headspace Analyzer. If analyses are performed manually, alter the operatingprocedures as required by the instrumentation.11.1 Install the chromatographic colu
30、mn and condition overnight at 100C, using normal carrier flow. Do not connect the exitend of the column to the detector or turn on detector gases during column conditioning.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 re
31、quiredHED Hydrogen 30 cm3 /min11.3 Set other parameters as follows:11.3.1 Oven Temperature50 to 60C.NOTE 6Higher oven temperatures may be required when other chromatographic columns are used, or when high-boiling solvents and late-elutingmaterials are being driven from the column.11.3.2 Dosing Needl
32、e150C.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 7Backflushing the carrier gas after VCM elutes can considerably shorten analysis time. After backflushing, allow adequate time forchromatographic conditions to stabilize
33、 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 high frequency noise and to provide adequate amplification of VCMsignal. Typical settings: filter 0.05 Hz and amplifier 2.12. Calibration
34、by Standard AdditionNOTE 8The 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 solution standards, or (3) a method of standard addition of VCM to polymer solutions.Pr
35、ocedure (3) is preferred to correct for any contribution the polymer makes to partitioning of VCM. Therefore, only procedure (3) is described.12.1 Accurately weigh headspace vial, cap, and septum using an analytical balance. Add 20 mL DMAc to weighed vial. Caploosely, and reweigh. In hood, prepare V
36、CM stock solution in this vial by quickly uncapping vial and adding 0.4 to 2 g liquid VCMfrom inverted freezer-cooled cylinder of VCM. Immediately cap vial tightly and mix well by shaking. Reweigh and calculate VCMconcentration by weight (ca 20 000 to 80 000 ppm). Dilute this stock solution by withd
37、rawing aliquots through the septum witha syringe and injecting into weighed, sealed vials of DMAc. Reweigh, and calculate VCM concentration (ca 50 ppm). This solutionis similarly diluted to yield a solution containing 1 to 5 ppm. If refrigerated, these working standards are stable for several weeks.
38、Multiple septum punctures shorten the working life of standards.NOTE 9Other methods of introducing VCM into the DMAc may be satisfactory. These should be shown to be accurate and safe.12.2 Add known volumes (microlitres) of the 1 to 5-ppm VCM in the DMAc standard to the polymer solutions prepared as
39、described in Section 13. Analyze solutions along with solvent blanks and the unknown, unspiked polymer solutions.13. Procedure for Sample Analysis13.1 Prepare two solvent blanks by adding 10.00 mL of DMAc to each of the two vials. Seal immediately with cap and septum.13.2 Cut up polymer film and bot
40、tle samples into small (;5 by 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 previously determinedsolubility or desired sensitivity, or both). Add 10.00 mL of DMAc to each vial and seal im
41、mediately with cap and septum. Beginvigorously shaking vials at once to facilitate dissolution. Immerse vials in the constant-temperature bath (9061C) until completeD4443 133solution is effected. Vigorously shake vials occasionally to aid solution. Alternatively, (1) immediately add a magnetic stirr
42、ing barto the vials and effect solution in an 85 to 95C water bath on a stirring-type hot plate or (2) place vials on/in a reciprocating shakerand heat with a heat lamp.NOTE 10Precaution: Vinyl chloride monomer may be present in the atmosphere of laboratories located in or near PVC manufacturing pla
43、nts andPVC fabricating plants. Therefore, it may be necessary to prepare the sealed vials of solvent blanks and sample mixtures inside a nitrogen-flushed glovebox or glove bag to avoid contamination by air-born VCM. Once sealed, the vials can be returned to the laboratory atmosphere for the remainde
44、r of theanalysis.13.4 After solution is attained (5 h), spike vials accordingly, using syringe through thick portion of septum: Vials 1 and 2, nospike; Vials 3 and 4, L of 1 to 5 ppm VCM in DMAc standard (see 11.1) ( L should give approximately double the GCresponse for VCM as in the unknown); Vials
45、 5 and 6, 2 L of 1 to 5 ppm VCM standard; and Vials 7 and 8, 3 L of 1 to 5ppm VCM standard.13.5 Shake all vials to ensure homogeneity. Heat vials in constant-temperature bath (90 6 1C) for 1 h.13.6 Adjust instrument injection time to inject maximum amount of headspace gas from each vial into the gas
46、 chromatographin the following sequence: solvent blank, 8, 6, 4, 2, 1, 3, 5, 7 solvent blank.NOTE 11It may be useful to measure vial pressure after analysis but before removing the vial from the bath. This ensures that the vial was correctlypressurized and no leaks occurred, either of which will neg
47、ate results.NOTE 12Experience with the method and system or development, or both, of response factors for one type of polymer may permit a reduction inthe number of analyses of spiked unknowns during a determination.NOTE 13For manual injections, heat syringe to 90C prior to withdrawing 1.0-mL headsp
48、ace sample for injection. Wear gloves for protection.13.7 Prior to plotting data points, construct two perpendicular axes on linear graph paper. The units of the x-axis should be interms of X, from 3 or less to +3 or more. The units of the y-axis should be from 0 to a positive value at least as larg
49、e as thenet average response value for Vials 7 and 8.13.8 Plot the net VCM response (average sample response for duplicate vials minus average blank response) for each vial pairon the y-axis versus the weight ofVCM that was added to each member of the pair on the x-axis. Draw the best straight line throughthe four points and extrapolate the line to intersect the x-axis. The distance from this point of intersection to the Point X = 0 onthe x-axis is a measure of the VCM content of the sample. See Fig. 1.NOT
