ASTM D5508-94a(2009)e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation:D5508 −94a(Reapproved 2009)
Standard Test Method for
Determination of Residual Acrylonitrile Monomer in Styrene-
Acrylonitrile Copolymer Resins and Nitrile-Butadiene
Rubber by Headspace-Capillary Gas Chromatography (HS-
CGC)
This standard is issued under the fixed designation D5508; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Reapproved with editorial changes in April 2009.
1. Scope* acrylonitrile (AN). Both vials are agitated for a specified time
under ambient conditions. After agitation, the vials are ther-
1.1 This test method covers the determination of the re-
mally equilibrated in a constant-temperature bath.
sidual acrylonitrile (RAN) content in nitrile-butadiene rubbers
(NBR), styrene-acrylonitrile (SAN) copolymers, and rubber- 3.2 After completion of the timed equilibration, an aliquot
modified acrylonitrile-butadiene-styrene (ABS) resins. of the heated headspace gas from each vial is injected into a
capillarygas-chromatographiccolumn.Anautomatedinjection
1.2 Any components that can generate acrylonitrile in the
system is used to effect the transfer. The capillary column will
headspace procedure will constitute an interference. The pres-
providethechromatographicresolutionnecessarytoisolatethe
ence of 3-hydroxypropionitrile in latices limits this procedure
AN from other volatiles potentially present. TheAN response
to dry rubbers and resins.
is measured using a nitrogen-specific detector (NPD).The raw
1.3 This standard does not purport to address all of the
data signal is converted to a relative RAN concentration
safety concerns, if any, associated with its use. It is the
through a standard addition calculation.
responsibility of the user of this standard to establish appro-
4. Significance and Use
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau-
4.1 A measurement of the residual acrylonitrile in nitrile
tionary statements are given in 6.3 and 6.4.
rubbers (NBR), styrene-acrylonitrile copolymers or ABS ter-
polymers will determine the polymer’s suitability for various
NOTE 1—There is no known ISO equivalent to this test method.
applications.
2. Referenced Documents
4.2 Under optimum conditions, the minimum level of de-
2.1 ASTM Standards:
tection of RAN in NBR, SAN, orABS terpolymers is approxi-
E691Practice for Conducting an Interlaboratory Study to
mately 50 ppb.
Determine the Precision of a Test Method
5. Apparatus
3. Summary of Test Method
5.1 Gas Chromatograph, equipped with a nitrogen-
phosphorus specific detector, backflush valve (see Fig. 1), split
3.1 Two dispersions (in o-dichlorobenzene) are prepared
and sealed in headspace vials for each polymer; one vial injector, and capable of accepting megabore (0.53 mm inside
diameter)fusedsilicacapillarycolumns.Detectormake-upgas
contains the polymer in solvent while the second vial contains
the polymer, solvent, plus a known standard addition of is required.
NOTE 2—The use of a backflush configuration will provide for
operating advantages, but its use is optional. Chlorinated solvents quench
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
the alkali bead in a nitrogen-phosphorous detector, producing a loss of
andisthedirectresponsibilityofSubcommitteeD20.70onAnalyticalMethodsand
signal. While the bead (signal) will recover as the solvent evacuates the
Section D20.70.02 on Chromatography.
detector, repeated quenching during a multi-run sequence may produce
Current edition approved April 1, 2009. Published April 2009. Originally
instabilities in the signal (and precision) over the sequence period.
ε1
approved in 1994. Last previous edition approved in 2001 as D5508-94a(2001) .
DOI: 10.1520/D5508-94AR09E01.
5.2 Automated Headspace Sampler, shall have a thermost-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
atted sample tray capable of 90°C heating with constant
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
heatingtimes.Automatedsamplingoftheheadspacegasinthe
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sample vials via a heated, constant-volume sample loop or
*A Summary of Changes 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
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D5508−94a (2009)
should be carried out in a hood or with proper personal
protection to minimize human exposure.)
6.4 o-Dichlorobenzene. (Warning—o-Dichlorobenzene is
moderatelytoxicandshouldonlybehandledinahoodorwith
proper personal protection to limit human exposure.)
NOTE 4—Each lot of o-dichlorobenzene should be analyzed under the
same instrumental conditions as the NBR samples to ensure that impuri-
ties are not present that will interfere with the acrylonitrile peak.
7. Sampling and Storage
7.1 The polymer test unit (sample) submitted for analysis
shall be supplied in the form of a 1 ⁄4 in. (45 mm) cube.
FIG. 1 Configuration of Eight-Port Valve Backflush Assembly
7.2 Alltestspecimensshallbetakenfromtheinteriorofthe
polymer-test unit to minimize the contribution of surface
effects on the residual-acrylonitrile level.
pressure balancing sampling mechanism is required. Conduct
7.3 Keep all polymer-test units in sealed containers. Ana-
sampling to the gas chromatograph by means of a heated
lyze test-specimen solutions immediately after preparation.
transfer line of minimum dead volume.
Report any analysis delays along with the test results.
5.3 Fused Silica Porous-Layer-Open-Tubular (PLOT) Cap-
illary Column , GS-Q, 30 m×0.53 mm inside diameter. 8. Calibration
NOTE 3—The column should be cut so as to havea3m section for the 8.1 Preparation of External Standard Solutions:
pre-column (Column 1) and a 27-m section for the analytical column
8.1.1 Tare (to the nearest 0.1 mg) a 25-mLvolumetric flask
(Column 2).
containing 10 mL of o-dichlorobenzene (DCB).
5.4 Variable Restrictor. 8.1.2 Weigh (to the nearest 0.1 mg) into the 25-mL volu-
metric flask 40 6 5 mg ofAN. Dilute to the mark with DCB.
5.5 Data-Recording Device—Astrip-chart recorder, record-
Label this solution as the “external-standard master solution”.
ing integrator, or computer-based data system is suitable.
8.1.3 Add 1 mL of the “external-standard master solution”
5.6 Wrist-Action Shaker.
to a clean 10-mL volumetric flask containing 2 mL of DCB.
Dilute to the mark with additional DCB. Label this solution as
5.7 Balance, analytical, 0.1-mg readability.
the “external-standard working solution”.
5.8 Headspace Vials, 20-mL capacity.
8.1.4 Prepare fresh “master” and “working” solutions each
5.9 Aluminum Crimp Caps, 20-mm diameter.
week and keep refrigerated at 4°C using Parafilm “M” to seal
volumetric stoppers.
5.10 Septa, TFE-fluorocarbon-faced silicone construction,
20-mm diameter.
8.2 Generation of the External-Standard Calibration
Curve:
5.11 Crimper, for 20-mm crimp caps.
NOTE 5—A new external-standard calibration curve should be gener-
6. Reagents and Materials
atedeachweektoaccountforanychangesintheANresponseduetoNPD
bead fluctuations.
6.1 Purity of Reagents—Chemicals of the highest purity
shall be used in all tests. Solvents shall have a minimum of
8.2.1 Transfer 5 mL of DCB into seven clean headspace
volatile impurities. Other grades shall only be used after
vials, using a volumetric pipet.
ascertaining that the reagent is free of interferences.
8.2.2 Add 0 (solvent blank), 1, 5, 10, 20, 60, or 100 µL of
the “external-standard working solution”, respectively, to the
6.2 Observeallhealthandsafetyrecommendationsforeach
vials.
chemical, as prescribed by the manufacturer.
8.2.3 Seal each vial immediately after addition with a
6.3 Acrylonitrile, 99+%. (Warning—Acrylonitrile is an
septum and crimp cap.
OSHA-regulated carcinogen and should not be released into
8.2.4 EstablishtheinstrumentparametersaslistedinAnnex
the laboratory atmosphere. All work involving acrylonitrile
A1.
8.2.5 Obtain the peak-area values for AN in each of the
standards.
J & W Scientific Catalog Number 115-3432, available from J & W Scientific,
91 Blue Ravine Road, Folsom, CA 95630-4714, or equivalent, has been found
9. Procedure
suitable for this purpose.
PE Number N930-2823, available from PE XPRESS, Perkin-Elmer Corp., 761
9.1 Determine the Target AN Weight for Polymer Test Units:
MainAve.,Norwalk,CT06859-0156,orequivalent,hasbeenfoundsuitableforthis
purpose.
Mettler AE163, available from Mettler-Toledo, Inc., 1900 Polaris Pkwy, B & J Brand, available from VWR Scientific Products, 1310 Goshen Pkwy,
Columbus, OH 43420, or equivalent, has been found suitable for this purpose. WestChester,PA19380,CatalogNumber061-4*DK,orequivalent,hasbeenfound
Aldrich Catalog Number 11 021-3, available fromAldrich Chemical Co., 1001 suitable for this purpose.
West Saint PaulAve., Milwaukee,WI 53233, or equivalent has been found suitable Available from Pelco International, P.O. Box 492499, Redding, CA
for this purpose. 96049–2477.
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D5508−94a (2009)
fromthenulladditionand3timesthetargetweight.Thepairingiscarried
9.1.1 Weigh (to the nearest 0.1 mg) into a clean headspace
through the calculations.
vial 400 6 10 mg of polymer. Add 5 mL of DCB, using a
volumetric pipet. Seal vial with septum and crimp cap. 9.3.2.3 For a Routine Test—Make no addition to one vial
9.1.2 Place the vial on a wrist-action shaker, set at maxi- and an addition of three times the target AN weight to the
remaining vial.
mum agitation for 16 h under ambient conditions.
9.3.3 Seal vials with crimper (immediately after an addi-
9.1.3 Analyzethesampleunderthesameinstrumentparam-
tion).
eters as was used to generate the external-standard calibration
9.3.4 Place the vials on a wrist-action shaker, set at maxi-
curve.
mum agitation for 16 h under ambient conditions.
9.1.4 Obtain the peak-area value for AN.
9.3.5 EstablishtheinstrumentparametersaslistedinAnnex
9.2 Preparation of AN Standard-Addition Solution:
A1.
9.3.6 Obtain the peak-area va
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