Document R21LwRdmxoj4d5kDoGE8vqdna

Designation: D 4443 - M AWE BICAN SOCIETY f OB TESTING AND MATE BIALS 1916 RncaSt .PhilatMpriia.Pa 19109 Rapnniid from it> Annual Book of ASTM Sundrth, Copyrighi ASTM If not lifted trv-ihf currant combined index, will >pp--r in tt* rwxt aditon Standard Method lor ANALYSIS FOR DETERMINING RESIDUAL VINYL CHLORIDE MONOMER CONTENT IN PPB RANGE IN VINYL CHLORIDE HOMO- AND CO-POLYMERS BY HEADSPACE GAS CHROMATOGRAPHY1 This standard is anted -"Ait the bed designation D 444}; the number immediately fbOowiag the designation indicates the year of original adoption or, in the case of revision, the year of last icvinoo. A number in parcathaa indicates the year of lan rempprcival. A superscript epsilon (<) indicates an editorial change since the last rtvinoe or ranproval. 1. Scope 1.1 This method is suitable for determining the residual vinyl chloride monomer (RVM) con tent of bomopolymer and copolymers of vinyl chloride down to a level of -5 ppb. 1.2 This method is applicable to any polymer form, such as resin, compound, film, bottle wall, etc. that can be dissolved in a suitable solvent 1.3 This standard may involve hazardous ma terials. operations, andequipment. This standard does not purport to address all ofthe safety prob lems associated with its use. It is the responsibil ity of whoever uses this standard to consult and establish appropriate safety and health practices anddetermine the applicabilityofregulatory limi tations prior to use. Specific precautionary state ments are given in Section 9 and Note 13. 2. Applicable Docnment 2.1 OSHA Standard: 29CFR 1919.1017--Vinyl Chloride2 3. Summary of Method 3.1 Samples of vinyl chloride containing pol ymers are dissolved in a suitable solvent in a dosed system. 3.2 The polymer solution and headspace are equilibrated at an elevated temperature. 3.3 Aliquots of headspace gas are injected into a gas chromatograph and the vinyl chloride mon omer is separated. The response of vinyl chloride monomer is determined by the use of one of several suggested detectors. 3.4 Calibration is accomplished using either (a) vinyl chloride monomer in nitrogen gas standards, (b) standard solutions containing known amounts of vinyl chloride monomer, or (c) a method of standard addition. 4. Significance and life 4.1 Vinyl chloride-containing polymers are widely used to package a variety of materials, including foods. 42 Vinyl chloride monomer has been shown to be a human carcinogen. Threshold toxicity value has not been established. 4.3 Plastic manufacturers, food packagers, government agencies, etc. have a need to know the residual vinyl chloride monomer content of vinyl chloride-containing polymers. 5. Abbreviations 5.1 VCM--Vinyl chloride monomer. 52 DMAc--N,N-dimethylacetamide. 6. Interferences 6.1 DMAc should be analyzed to determine the absence of interferences at the vinyl chloride monomer gas chromatography (GC) retention time. 6.2 Other solvents, monomers, or compound- 1 Tbs method is under the jurisdiction of ASTM Committee P-20on Plastics sod is tbe direct responsibility ofSubcommittee D20.70 oo Analytical Methods. Cunrnt edition approved Nov. 30, I9S4. Published Januarv 1985. 1 Available from Superintendent of Documents, US Govern ment Priming Office. Washington. DC 20402. i i j i BG05053 0726001 1 D 4443 mg aids may cause interference at the vinyl chlo ride monomer GC retention time. 7. Apparatus 7.1 Gas Chromatography, equipped with either a flame ionization detector (FID), a photo ionization detector (PID), or a Hall electrocon ductivity detector (HED). backflushing valve, and capable of either automatic (Note 1) or man ual sampling (Note 2) and analyzing the beadspace vapors contained in a sealed vial. Note I--Pcrkia-Elmcr Model F-40, F-42. or F-4J Headspace Analyzer.' backflushing capabilities, ther mostatically controlled sample vial tray, and other re quired associated accessories can fulfill these require ments. Note 2--If the analyses are to be performed man ually. that is by syringe injection into other models of chromatographs, then the following equipment will also be needed: (J) Constant-temperature bath or oven capable of maintaining a temperature of 90 l*C. (2) Gas-tight GC syringes for sampling and injection. (3) Sample bottles with fluoropolymer faces septa and caps (size optional). () Gloves for handling hot syringes. 7.2 Chromatographic Column, 3 % OV-101 on 80/100 mesh Chromosorb WHP*. Ik in. (3.2 mm) outside diameter by 2 ft (0.6 m), stainless steel connected through Ik in. "tee" to 0.19% picric acid on 80/100 mesh Carbopack C\ Ik in. (3.2 mm) outside diameter by 8 ft (2.4 m), stain less steel. Note 3--Any column pocking that will resolve VCM from interferences and elute VCM in a reasonable length oftime (1 to 5 min) is satisfactory. For example, a 3 ft (0.9 m) by VI in. (3.2 mm) outside diameter column containing 0.19 % picric acid on 80/100 mesh Carbopack C can replace the recommended 3 % OV 10) column. Settings recommended in 11.3.1 may have to be modified to suit the packing materia] being used. 7.3 Two-Channel, I-mV, Full-Scale Re corder--A single-channel recorder is sufficient if the GC-detector signal is sent to a computer system or integrator to store the total VC peak area. An electronic integrator is recommended for measurement of peak areas. Note 4--The VCM peak must be kept on scale to manually measure tbc correct peak area or peak bright One method of achieving this without undue operator 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. The other channel is set at a lower sensitivity to keep the larger peaks from higbVCM samples on scale. 7.4 Detector Output Filter/Amplifier--The extreme sensitivity of this method is best realized when the detector (usual!) operated at the max imum sensitivity) output is (a) filtered to remove the high-frequency noise and (b) amplified to give a visible or measurable signal. The filter/ amplifier is connected in series between the de tector and the recorder/computer. Note 5--A Spectrum Scientific Model I02IA fil ter/amplifier' can fulfil) these requirements. Other filter/amplifiers may be available that are suitable. 7.5 Sample Headspace Vials, glass. 23 ml_, with fluoropolymer-iined septa and aluminum caps. 7.6 Vial Sealer. 7.7 Analytical Balance, capable of weighing to 0.001 g. 7.8 Statistical Programmable Calculator. Note 6--A programmable calculator is not abso lutely necessary, but can save a considerable amount of time when Urge numbers ofsamples are bring analyzed. 8. Reagents and Materials 8.1 Vinyl Chloride Monomer (neat), pure, preferably in small cylinder. 8.2 Standard Cylinders, vinyl chloride mon omer in nitrogen at 1 and 10 ppm by volume. 8.3 Hydrogen Cylinder, prepurified gas. 8.4 Nitrogen, oxygen-ftec. Note 7--Helium may replace nitrogen as the car rier 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 remove chromatographic inter ferences. 9. Safety Precautions 9.1 Vinyl chloride monomer is a carcinogen and exposure by inhalation or dermal contact, or both, is to be avoided. Refer to OSHA Standard 29 CFR 1919.1017 for regulated levels of expo sure. DMAc is a teratogen. The use of a properly functioning hood and septum-sealed sample con tainers are recommended. 9.2 Avoid all contact with heated parts of the gas chromatograph, hot syringes, and sample bot tles. Handle all electrical connections with care. 'Available from Perkio-Elmer Corp., Main Avc., Norwalk. CT 06*56. 4Co*umn paeld&f is available from Supdco. toe.. P.O. Box 62*, >46 S. Wicr Sl. BeOefoote. PA 16*23. 'AvsDabk from Spectrum Scientific Corp.. 2401 Ogleiowii Rd.. Newark. DE 19711. 2 BFG05054 1 Ch D 4443 9.3 Oner healed, sample mis are under pres sure After analysis, relieve the pressure with a hypodermic synnge needle vented into a charcoal slug or vent tube leading to a hood before remov ing vials from the water bath. 10. Sampling and Storage 10.1 Keep all polymer samples in lightly sealed jars or tightly wrapped aluminum foil prior to analysis. Dissolved polymer samples must be kept in septum-sealed vials or bottles until analyzed. Polymer solutions stored longer than 24 h should be maintained under refrigera tion. 11. Preparation of Gas Chromatograph Non 8--All conditions in this section refer to the Perkin-EJmcr Headspace Analyzer. If analyses are per formed manually, alter the operating procedures as required by the instrumentation. 11.1 Install the chromatographic column and condition overnight at 100*C, using normal car rier flow. Do not connect the exit end of the column to the detector or turn on detector gases during column conditioning 11.2 Set the flow of detector gases is follows: Dcucur G Flow FtD PID HED Hydrates Air Not required Hydrates 30 to 40 cre'/inui 300 to 400 cmVmio 30 em'/mn 11.3 Set other parameters as follows: 11.3.1 Oven Temperature--50 to 60*C. Note 9--Higher oven temperatures may be re quired when other chromatographic columns are used, or when high-boiling solvents and late-eluting materials are being driven from the column. 11.3.2 Dosing Needle-- 150*C. 11.3.3 Injection Block Temperature--200*C. 11.3.4 Constant--Temperature Bath--90 1.0'C. 11.3.5 Carrier--Gas Flow Rate--30 cm3/ min. Notz 10--Backtlushing the carrier gas after VCM elutes can considerably shorten analysis time. After badeftushing. allow adequate time for chromatographic conditions to stabilize before making another injection. 11.3.6 Detector Temperature: 11.3.6.1 FID--250*C. 11.3.6.2 PID-- 150'C. 11.3.6.3 HED--880`C. 11.3.7 Filter/Amplifier--Adjust as needed to remove high frequency noise and to provide ad equate amplification of VCM signal Typical settings: filter - 0.05 Hz and amplifier - 2x. 12. Calibration by Standard Addition Note II--The gas chromatograph is calibrated us ing either procedure: <a) VCM in nitrogen gas standards and a previously determined partioon coefficient for VCM between DMAc and headspace, (b) VCM solu tion standards, or (c) a method of standard addition of VCM to polymer solutions. Procedure (c) is preferred to correct for any contribution the polymer makes to partitioning of VCM. Therefore, only procedure (c) is described. 12.1 Accurately weigh headspace vial, cap, and septum using an analytical balance. Add 20 mL DMAc to weighed vial. Cap loosely, and reweigh. In hood, prepare VCM stock solution in this vial by quickly uncapping vial and adding 0.4 to 2 g liquid VCM from inverted freezercooled cylinder of VCM. Immediately cap vial tightly and mix well by shaking. Reweigh and calculate VCM concentration by weight (ca 20 000 to 80 000 ppm). Dilute this stock solution by withdrawing aliquots through septum with syringe and injecting into weighed, sealed vials of DMAc. Reweigh, and calculate VCM concentration (ca 50 ppm). This solution is similarly diluted to yield solution containing 1 to 5 ppm. If refrigerated, these working standards are stable for several weeks. Multiple septum punctures shorten working life of standards. Note 12--Other methods ofintroducing VCM into the DMAc may be satisfactory. These should be shown to be accurate and safe. 12.2 Add known volumes (yiLs) of the 1 to 5 ppm VCM in DMAc standard to the polymer solutions prepared as described in Section. 13. Analyze solutions along with solvent blanks and the unknown, unspiked polymer solutions. 13. Procedure for Sample Analysis 13.1 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 bottle 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, 0.01 g, of polymer (1.00 to 4.00 g depending on previously determined solubility or desired sensitivity, or both). Add 10.00 mL of DMAc to each vial and seal immediately with cap and septum. Begin vigorously shaking vials 3 ! ; ; i 20726003 $FG05055 D 4443 at once to facilitate dissolution. lmmerv vials in constant-temperature hath (90 a I*0) until com plete solution is effected. Vigorously shake "vials occasionally to aid solution. Alternatively, (/) immediately add a magnetic stirring bar to the vials and effect solution in an 85 to 95*C water bath on a stirring-type hot plate, or (2) place vials on/in a reciprocating shaker and beat with a heat lamp. Noth 13--VCM may be present in the atmosphere of laboratories located in or near PVC manufacturing plants and "PVC fabricating plants. Therefore, it may be necessary to prepare the sealed vials ofsolvent blanks and sample mixtures inside a nitrogen-flushed glove box or glove bag to avoid contamination by air-bom VCM. Once sealed, the vials can be returned to the laboratory atmosphere for the remainder of the analy sis. 13.4 After solution is attained (5 h), spike vials accordingly, using syringe through thick portion of septum: vials 1 and 2, no spike; vials 3 and 4. x pL of 1 to 5 ppm VCM in DMAc standard (see 11.1) (x pL should give approxi mately double the GC response for VCM as in the unknown); vials S and 6, 2 x pL of I to 3 ppm VCM standard; and vials 7 and 8, 3 x pL of 1 to 5 ppm VCM standard. 13.3 Shake all vials to assure homogeneity. Heat vials in constant-temperature bath (90 1*0 for 1 h. 13.6 Adjust instrument injection time to in ject maximum amount of headspace gas from each vial into the gas chromatograph in the fol lowing sequence: solvent blank, 8, 6, 4, 2, 1, 3, 3, 7 solvent blank. Noth 14--It may be useful to measure vial pressure after analysis but before removing vial from hath. This assures vial was correctly pressurized and no leaks occurred, either of which will negate results. Note 13--Experience with the method and system or development, or both, of response factors for one type of polymer may permit a reduction in the number ofanalyses ofspiked unknowns during a determination. Note 16--For manual injections, beat syringe to 90*C prior to withdrawing 1.0-mL hradspapr sample for injection. Wear gloves for protection. 13.7 Preparatory to plotting data points, con struct two perpendicular axes on linear graph paper The units of the x-axis should be in terms of X. from -3x or less lo + 3x or more. The units of the y-axis should be from 0 to a positive value at least as large as the net average response value for vials 7 and 8. 13.8 Plot the net VCM response (average sam ple response for duplicate vials minus average blank response) for each vial pair on the y-axis versus the weight of VCM that was added to each member of the pair on the x-axis. Draw the best straight line through the four points and extrap olate the line to intersect the x-axis. The distance from this point of intersection to the point X 0 on the x-axis is a measure of the VCM content of the sample. See Fig. I. Note 17--A computer program can be used to plot and extrapolate the data. 14. Calculation 14.1 Calculate the VCM content in the un known by determining the ng VCM obtained in the unknown (from the plot or computer) and dividing by the weight of polymer in the vial. Report findings in ppb (ng/g). 15. Precision and Bias* 13.1 The following values were determined for the coefficients of variation of this method on the basis of an interlaboratory test program (1981-82) involving 8 laboratories reporting re sults of at least duplicate analyses: 13.2 Coefficient of variation (CV) at a residual vinyl chloride monomer level of approximately lOppb: CV for Copolymer Film CV for HomopotyrorT Pelleu lotralaboratory Inlertaborelory 33.5 51 37.7 % 14.9 * 34.8 % 13.3 Bias--Since no absolute method is avail able for comparison, no statement can be pre sented for this method. `Supporting data are available on loan u ASTM Headquar* Krv Roques RJC D20-I1I6 4 BFG05056 D4U3 -3Jt -?X -X 0 X 2* 3X nr VCN ir nj VCM *dd*d FIC. I Staadard Additioai ExtrapobtMa ho< The A merican Society far Testing and Materials takes no position respecting the validity ofany patent rights asserted in connection with any item mentioned in this standard Users ofthis standard ore expressly advised that determination ofthe validity of any such patent ng/us. and the nsk ofinfringement ofsuch rights, are entirely their own responsibility This standard is subject to revision at any time by the responsible technical committee and must be reviewed everyfive years and if not revised, either reapproved or wtthdrann Your comments are invtted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments will receive careful consideration at a meeting of the responsible technical committee which you may attend If you fee! that your comments have not received a fair hearmg you should make your views known to the ASTM Committee on Standards. 1916 Race St. Philadelphia, Pa. 19103 0726005 5N i