ASTM_D_4526_-_12.pdf

Designation:D452612Standard Practice forDetermination of Volatiles in Polymers by Static HeadspaceGas Chromatography1This standard is issued under the fixed designation D4526;the 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()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 Headspace gas chromatography(GC)involves the de-termination of volatile components in a polymer solution bygas chromatography of a vapor phase in thermal equilibriumwith the sample matrix.Volatiles in finely ground insolublepolymers can also be determined with and without an extract-ing solvent.1.2 This practice provides two procedures:1.2.1 Procedure AAutomatic headspace analysis.1.2.2 Procedure BManual injection headspace analysis.1.3 This standard does not purport to address all of thesafety concerns,if any,associated 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 in Section 6.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D4322 Test Method for Residual Acrylonitrile MonomerStyrene-Acrylonitrile Copolymers and Nitrile Rubber byHeadspace Gas Chromatography(Withdrawn 2010)3E260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid Chromatography3.Significance and Use3.1 For various reasons,one may want to measure the levelof unreacted or residual monomer,water,or other volatilecomponents in a polymer sample.3.2 Volatiles of interest are often at trace concentrations.Headspace analysis is suited for determination of these tracecomponents which often cannot be determined by conventionalgas chromatography because of sample decomposition orinterferences.3.3 For polymer analysis,sample treatment for headspaceanalysis is simpler than conventional gas chromatography,where precipitation steps may be required to prevent polymercontamination of the chromatographic column.3.4 This headspace practice will be able to determinequalitatively any component with sufficient vapor pressure.Itis capable of yielding semiquantitative results and can be usedfor relative comparisons between samples.4.Apparatus4.1 Gas Chromatograph,equipped with an appropriatedetector and backflush valve.4.1.1 For Procedure A,an Automated Headspace Sampler,4,5including backflush capability,thermostated sample tray,and associated accessories fulfill these requirements whileproviding for automatic sequential sampling of headspacevapors.4.1.2 Procedure B requires the following additional equip-ment:4.1.2.1 Constant-Temperature Bath,capable of maintaining90 6 1C.4.1.2.2 Gas-Tight Gas Chromatographic Syringes,whichcan be heated to 90C for sampling and injection.4.1.2.3 Valve,6-port for backflush assembly.NOTE2Appropriate detectors could include the following:(a)Flame ionization(FID)for general organic volatiles,1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved Dec.15,2012.Published December 2012.Originallyapproved in 1985.Last previous edition approved in 2007 as D4526-97(2007).DOI:10.1520/D4526-12.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4The sole source of supply of the apparatus known to the committee at this timeis Perkin-Elmer Corp.,Main Ave.,Norwalk,CT 06856.5If you are aware of alternative suppliers,please provide this information toASTM International Headquarters.Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1(b)Electron capture(EC)for halogenated species,(c)Nitrogen-phosphorous(NPD)for acrylonitrile,(d)Thermal conductivity(TC)for water,and(e)Hall electroconductivity or photoionization(PID)for vinyl chlo-ride.4.2 Chromatographic Columns:4.2.1 Packed Column AnalysisColumn packings5,6foundto be useful for residual monomers(for example,acrylonitrile,vinyl chloride)include Chromosorb or Porapak porous poly-mer packings,0.4%Carbowax 1500 liquid phase on CarbopakC support,or 0.19%picric acid on Carbopak C support.Othercolumns can be used after it is determined that t