1、Designation: D 5508 94a (Reapproved 2001)e1Standard Test Method forDetermination of Residual Acrylonitrile Monomer in Styrene-Acrylonitrile Copolymer Resins and Nitrile-ButadieneRubber by Headspace-Capillary Gas Chromatography (HS-CGC)1This standard is issued under the fixed designation D 5508; the
2、number immediately following the designation 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.e1NO
3、TESeveral sections have been changed editorially in March 2001.1. Scope1.1 This test method covers the determination of the re-sidual acrylonitrile (RAN) content in nitrile-butadiene rubbers(NBR), styrene-acrylonitrile (SAN) copolymers, and rubber-modified acrylonitrile-butadiene-styrene (ABS) resin
4、s.1.2 Any components that can generate acrylonitrile in theheadspace procedure will constitute an interference. The pres-ence of 3-hydroxypropionitrile in latices limits this procedureto dry rubbers and resins.1.3 This standard does not purport to address all of thesafety concerns, if any, associate
5、d 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 precau-tionary statements are given Note 4 and Note 5.NOTE 1There is no current ISO equivalent
6、test method for residualacrylonitrile (RAN) determinations.2. Referenced Documents2.1 ASTM Standards:E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method23. Summary of Test Method3.1 Two dispersions (in o-dichlorobenzene) are preparedand sealed in headspa
7、ce vials for each polymer; one vialcontains the polymer in solvent while the second vial containsthe polymer, solvent, plus a known standard addition ofacrylonitrile (AN). Both vials are agitated for a specified timeunder ambient conditions. After agitation, the vials are ther-mally equilibrated in
8、a constant-temperature bath.3.2 After completion of the timed equilibration, an aliquotof the heated headspace gas from each vial is injected into acapillary gas-chromatographic column. An automated injectionsystem is used to effect the transfer. The capillary column willprovide the chromatographic
9、resolution necessary to isolate theAN from other volatiles that may be present. The AN responseis measured using a nitrogen-specific detector (NPD). The rawdata signal is converted to a relative RAN concentrationthrough a standard addition calculation.4. Significance and Use4.1 A measurement of the
10、residual acrylonitrile in nitrilerubbers (NBR), styrene-acrylonitrile copolymers or ABS ter-polymers will determine the polymers suitability for variousapplications.4.2 Under optimum conditions, the minimum level of de-tection of RAN in NBR, SAN, or ABS terpolymers is approxi-mately 50 ppb.5. Appara
11、tus5.1 Gas Chromatograph, equipped with a nitrogen-phosphorus specific detector, backflush valve (see Fig. 1), splitinjector, and capable of accepting megabore (0.53 mm insidediameter) fused silica capillary columns. Detector make-up gasis required.NOTE 2The use of a backflush configuration will pro
12、vide for operat-ing advantages, but its use is optional. Chlorinated solvents quench thealkali bead in a nitrogen-phosphorous detector, producing a loss of signal.While the bead (signal) will recover as the solvent evacuates the detector,repeated quenching during a multi-run sequence may produce ins
13、tabilitiesin the signal (and precision) over the sequence period.5.2 Automated Headspace Sampler, should have a thermo-statted sample tray capable of 90C heating with constantheating times. Automated sampling of the headspace gas in thesample vials via a heated, constant-volume sample loop orpressur
14、e balancing sampling mechanism is required. Samplingto the gas chromatograph should be via a heated transfer line of1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Oct.
15、 15, 1994. Published December 1994. Originallypublished as D 5508 94. Last previous edition D 5508 94.2Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.minimum dead volume.5.3 Fused Silica Poro
16、us-Layer-Open-Tubular (PLOT) Cap-illary Column3, GS-Q, 30 m 3 0.53 mm inside diameter.NOTE 3The column should be cut so as to havea3msection for thepre-column (Column 1) and a 27-m section for the analytical column(Column 2).5.4 Variable Restrictor.45.5 Data-Recording DeviceA strip-chart recorder, r
17、ecord-ing integrator, or computer-based data system is suitable.5.6 Wrist-Action Shaker.5.7 Balance,5analytical, 0.1-mg readability.5.8 Headspace Vials, 20-mL capacity.5.9 Aluminum Crimp Caps, 20-mm diameter.5.10 Septa, TFE-fluorocarbon-faced silicone construction,20-mm diameter.5.11 Crimper, for 20
18、-mm crimp caps.6. Reagents and Materials6.1 Purity of ReagentsChemicals of the highest purityshall be used in all tests. Solvents should have a minimum ofvolatile impurities. Other grades should only be used afterascertaining that the reagent is free of interferences.6.2 Observe all health and safet
19、y recommendations for eachchemical, as prescribed by the manufacturer.6.3 Acrylonitrile,699+%.NOTE 4Warning: Acrylonitrile is an OSHA-regulated carcinogenand should not be released into the laboratory atmosphere. All workinvolving acrylonitrile should be carried out in a hood or with properpersonal
20、protection to minimize human exposure.6.4 o-Dichlorobenzene.7NOTE 5Warning: o-Dichlorobenzene is moderately toxic and shouldonly be handled in a hood or with proper personal protection to limithuman exposure.NOTE 6Each lot of o-dichlorobenzene should be analyzed under thesame instrumental conditions
21、 as the NBR samples to ensure that impuri-ties are not present that will interfere with the acrylonitrile peak.7. Sampling and Storage7.1 The polymer test unit (sample) submitted for analysisshould be supplied in the form of a 134in. (45 mm) cube.7.2 All test specimens should be taken from the inter
22、ior ofthe polymer-test unit to minimize the contribution of surfaceeffects on the residual-acrylonitrile level.7.3 Keep all polymer-test units in sealed containers. Ana-lyze test-specimen solutions immediately after preparation.Report any analysis delays along with the test results.8. Calibration8.1
23、 Preparation of External Standard Solutions:8.1.1 Tare (to the nearest 0.1 mg) a 25-mL volumetric flaskcontaining 10 mL of o-dichlorobenzene (DCB).8.1.2 Weigh (to the nearest 0.1 mg) into the 25-mL volu-metric flask 40 6 5 mg of AN. Dilute to the mark with DCB.Label this solution as the “external-st
24、andard master solution”.8.1.3 Add 1 mL of the “external-standard master solution”to a clean 10-mL volumetric flask containing 2 mL of DCB.Dilute to the mark with additional DCB. Label this solution asthe “external-standard working solution”.8.1.4 Prepare fresh “master” and “working” solutions eachwe
25、ek and keep refrigerated at 4C using Parafilm8“M” to sealvolumetric stoppers.8.2 Generation of the External-Standard Calibration Curve:NOTE 7A new external-standard calibration curve should be gener-ated each week to account for any changes in the AN response due to NPDbead fluctuations.8.2.1 Transf
26、er 5 mL of DCB into seven clean headspacevials, using a volumetric pipet.8.2.2 Add 0 (solvent blank), 1, 5, 10, 20, 60, or 100 L ofthe “external-standard working solution”, respectively, to thevials.8.2.3 Seal each vial immediately after addition with aseptum and crimp cap.8.2.4 Establish the instru
27、ment parameters as listed in AnnexA1.8.2.5 Obtain the peak-area values for AN in each of thestandards.9. Procedure9.1 Determine the Target AN Weight for Polymer Test Units:9.1.1 Weigh (to the nearest 0.1 mg) into a clean headspacevial 400 6 10 mg of polymer. Add 5 mL of DCB, using avolumetric pipet.
28、 Seal vial with septum and crimp cap.9.1.2 Place the vial on a wrist-action shaker, set at maxi-mum agitation for 16 h under ambient conditions.9.1.3 Analyze the sample under the same instrument param-eters as was used to generate the external-standard calibrationcurve.3J nitrile rubber; residualacr
29、ylonitrile; styrene-acrylonitrile copolymersANNEX(Mandatory Information)A1. PARAMETERS FOR GAS CHROMATOGRAPH AND HEADSPACE SAMPLERA1.1 Gas Chromatograph Parameters:A1.1.1 Injection ModeCapillary, split.A1.1.2 Injection Temperature250C.A1.1.3 Carrier GasHelium.A1.1.4 Linear Flow Velocity38 cm/s (at a
30、pproximately130C).A1.1.5 Oven Temperature ProfileIsothermal, 155C.A1.1.6 Detector TypeNitrogen-phosphorus detector.A1.1.7 Detector Temperature300C.A1.2 Headspace Sampler Parameters:A1.2.1 Bath Temperature90C.A1.2.2 Equilibration Time3 hour.A1.2.3 Sample Loop Size3 mL.A1.2.4 Sample Loop Temperature11
31、0C.TABLE 1 Type IPrecision (Residual Acrylonitrile in Nitrile-Butadiene Rubber)Material Mean, ppmWithin LaboratoriessrArB(r)CA 0.66 0.07 0.20 30.5B 1.25 0.13 0.35 28.4C 1.12 0.23 0.64 57.7D 0.17 0.04 0.11 67.7E 0.16 0.05 0.13 82.5“A” 1.84 0.07 0.19 10.3“B” 0.66 0.04 0.12 17.9“C” 38.5 2.06 5.77 15.0“
32、D” 10.8 0.73 2.04 18.9“E” 1.25 0.12 0.34 27.3Asr = Within-laboratory standard deviation.Br = Repeatability (in measurement units).C(r) = Repeatability (in percent).D 55084A1.2.5 Injection Cycle Parameters(For volume-controlled headspace sampler).SUMMARY OF CHANGESCommittee D20 has identified the loc
33、ation of selected changes to this standard since the last issue(D 5508 94a) that may impact the use of this standard.(1) Five year review with editorial changes.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this sta
34、ndard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be revi
35、ewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsib
36、le technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
37、nshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE A1.1 Parameter
38、s for Gas Chromatograph and HeadspaceSamplerTime min:s Action Description:01 Probe Needle enters vial:03 Pressure Vial pressurization begins:18 Pressure Vial pressurization stops:19 Vent/fill loop Initialize sample loop filling:28 Vent/fill loop Close sample loop-loop filled:33 Inject Flush sample onto analytical column1:03 Vent/fill loop Open loop to vent1:04 Pressure Initialize sample loop cleaning2:34 Pressure Stop carrier flow through sample loop2:35 Vent/fill loop Close vent2:36 Inject Stop injection cycle2:37 Probe Needle exits vialD 55085
