ASTM_F_2013_-_10.pdf

Designation:F201310Standard Test Method forDetermination of Residual Acetaldehyde in PolyethyleneTerephthalate Bottle Polymer Using an Automated StaticHead-Space Sampling Device and a Capillary GC with aFlame Ionization Detector1This standard is issued under the fixed designation F2013;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.Scope1.1 This test method covers a gas chromatographic proce-dure for the determination of the ppm residual acetaldehyde(AA)present in poly(ethylene terephthalate)(PET)homo-polymers and co-polymers which are used in the manufactureof beverage bottles.This includes sample types of bothamorphous and solid-stated pellet and preform samples,asopposed to the bottle test,Test Method D4509,an acetaldehydetest requiring 24 h of desorption time at 23C into the bottleheadspace and then the concentration of the headspace quan-tified by a similar GC method.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.2.Referenced Documents2.1 ASTM Standards:2D4509 Test Methods for Determining the 24-Hour Gas(AIR)SpaceAcetaldehyde Content of Freshly Blown PETBottles(Withdrawn 2004)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 The terms employed in this test method are commonlyused in normal laboratory practice and require no specialcomment.4.Summary of Test Method4.1 A specified size(1000 m)of granulated sample isweighed into a 20-mL head-space vial,sealed,and then heatedat 150C for 60 min.After heating,the gas above the sealedsample of PET polymer is injected onto a capillary GC column.The acetaldehyde is separated,and the ppm of acetaldehyde iscalculated.5.Significance and Use5.1 This test method is of particular use as a quality controltool for a molding or synthesis operation.Acetaldehyde is avolatile degradation product generated during melt processingof PET.Thus,it becomes trapped in the sidewalls of a moldedarticle and desorbs slowly into the contents packaged therein.In some foods and beverages AA can impart an off-taste that isundesirable,thus,it is important to know its concentration inPET articles that are to be used in food contact applications.5.2 The desorption conditions of 150 C for 60 min are suchthat no measurable AA is generated by the sample during thedesorption process.6.Sources of Error6.1 Abias is known to exist if the ratio of sample mass(mg)to head-space vial volume(mL)exceeds a value of ten.6.2 Acetaldehyde is very volatile and must be handledcarefully to avoid sample loss during the calibration procedure.Storing the standard vials in a refrigerator(4 6 2C)is a mustto minimize the error due to volatility.6.3 Failure to achieve a tight seal on the head-space vial willresult in the loss of acetaldehyde during storage anddesorption,producing a false low value.6.4 Failure to grind the sample to the appropriate particlesize may lead to a false low value for residual AA due to theincreased path length for desorption.1This test method is under the jurisdiction ofASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition approved Oct.1,2010.Published October 2010.Originallyapproved in 2000.Last previous edition published in 2005 as F2013 05.DOI:10.1520/F2013-10.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.5 Samples submitted for“residual AA measurement”should be stored in a freezer(10C)until they are tested.Failure to do so can result in lower than expected results.6.6 Excessive grinding of samples can cause residual AAcontained therein to be desorbed.Extensive excessive grindingcan lead to actual melting of the polymer and AA generation.Samples which have been chilled in liquid nitrogen properlyshould only be in the grinder for;30 s or less.7.Apparatus7.1 Gas Chromatograph,equipped with a flame ionizationdetector.7.2 Integrator or a PC with data acquisition software.7.3 Head-Space Sampler(a static head-space sampler).7.4 Column,30-m by 0.53-mm inside diameter(DV