1、Designation: D 5508 94a (Reapproved 2009)1Standard 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 n
2、umber 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 () indicates an editorial change since the last revision or reapproval.1NOTER
3、eapproved with editorial changes in April 2009.1. Scope*1.1 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) resins.1.2 Any compo
4、nents 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, associated with its use.
5、 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 in 6.3 and 6.4.NOTE 1There is no known ISO equivalent to this test method.
6、2. Referenced Documents2.1 ASTM Standards:2E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 Two dispersions (in o-dichlorobenzene) are preparedand sealed in headspace vials for each polymer; one vialcontains the polymer in
7、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 a constant-temperature bath.3.2 After completion of the tim
8、ed 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 resolution necessary to isolate theAN from other volatiles p
9、otentially 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 residual acrylonitrile in nitrilerubbers (NBR), styrene-acry
10、lonitrile 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. Apparatus5.1 Gas Chromatograph, equipped with a nitrogen-phosphoru
11、s 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 provide for operat-ing advantages, but its use is optional. Chl
12、orinated 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 instabilitiesin the signal (and precision) over the sequence pe
13、riod.5.2 Automated Headspace Sampler, shall have a thermostat-ted sample tray capable of 90C heating with constant heatingtimes. Automated sampling of the headspace gas in the samplevials via a heated, constant-volume sample loop or pressurebalancing sampling mechanism is required. Conduct sampling1
14、This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.70 on Analytical Methods andSection D20.70.02 on Chromatography.Current edition approved April 1, 2009. Published April 2009. Originallyapproved in 1994. Last previous edi
15、tion approved in 2001 as D 5508 - 94a(2001)1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of C
16、hanges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.to the gas chromatograph by means of a heated transfer line ofminimum dead volume.5.3 Fused Silica Porous-Layer-Open-Tubular (PLOT) Cap
17、-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, record-ing integrator, or compute
18、r-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-mm crimp caps.6. Reagents and M
19、aterials6.1 Purity of ReagentsChemicals of the highest purityshall be used in all tests. Solvents shall have a minimum ofvolatile impurities. Other grades shall only be used afterascertaining that the reagent is free of interferences.6.2 Observe all health and safety recommendations for eachchemical
20、, as prescribed by the manufacturer.6.3 Acrylonitrile,699+%.(WarningAcrylonitrile is anOSHA-regulated carcinogen and should not be released intothe laboratory atmosphere. All work involving acrylonitrileshould be carried out in a hood or with proper personalprotection to minimize human exposure.)6.4
21、 o-Dichlorobenzene.7(Warningo-Dichlorobenzene ismoderately toxic and should only be handled in a hood or withproper personal protection to limit human exposure.)NOTE 4Each lot of o-dichlorobenzene should be analyzed under thesame instrumental conditions as the NBR samples to ensure that impuri-ties
22、are not present that will interfere with the acrylonitrile peak.7. Sampling and Storage7.1 The polymer test unit (sample) submitted for analysisshall be supplied in the form of a 134 in. (45 mm) cube.7.2 All test specimens shall be taken from the interior of thepolymer-test unit to minimize the cont
23、ribution 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 Preparation of External Standard Solutions:8.1.
24、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-standard master solution”.8.1.3 Add 1 mL of the “e
25、xternal-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 eachweek and keep refrigerated at 4C using Parafilm8“M
26、” to sealvolumetric stoppers.8.2 Generation of the External-Standard Calibration Curve:NOTE 5A new external-standard calibration curve should be gener-ated each week to account for any changes in theAN response due to NPDbead fluctuations.8.2.1 Transfer 5 mL of DCB into seven clean headspacevials, u
27、sing 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 instrument parameters as listed in AnnexA1.8.2.5 Obtain
28、 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. Seal vial with septum and crimp cap.3J nitrile r
29、ubber; residualacrylonitrile; styrene-acrylonitrile copolymersTABLE 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.
30、07 0.19 10.3“B” 0.66 0.04 0.12 17.9“C” 38.5 2.06 5.77 15.0“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 5508 94a (2009)14ANNEX(Mandatory Information)A1. PARAMETERS FOR GAS CHROMAT
31、OGRAPH 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 approximately130C).A1.1.5 Oven Temperature ProfileIsothermal, 155C.A1.1.6 Detector TypeNitrogen-phospho
32、rus 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 Temperature110C.A1.2.5 Injection Cycle Parameters(For volume-controlled headspace sampler).SUMMARY OF CHANGESCommit
33、tee D20 has identified the location of selected changes to this standard since the last issue(D 5508 - 94a(2001)1) that may impact the use of this standard. (April 1, 2009)(1) Editorially revised ISO equivalency statement.(2) Removed permissive language in sections 3.2, 5.2, 6.1, 6.2,7.1, 7.2, 12.3,
34、 12.3.1, and 12.4.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement o
35、f such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for
36、additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known t
37、o 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 Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at
38、 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 Parameters for Gas Chromatograph and HeadspaceSamplerTime min:s Action Description:01 Probe Needle enters vial:03 Pressure Vial pressurization begins:18
39、 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 5508 94a (2009)15
