ASTM F2013-2005 Standard Test Method for Determination of Residual Acetaldehyde in Polyethylene Terephthalate Bottle Polymer Using an Automated Static Head-Space Sampling Device anr.pdf
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1、Designation: F 2013 05Standard 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 F 2013; the numb
2、er 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.1. Scope
3、1.1 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 so
4、lid-stated pellet and preform samples, asopposed to the bottle test, Test Method D 4509, an acetalde-hyde test requiring 24 h of desorption time at 23C into thebottle headspace and then the concentration of the headspacequantified by a similar GC method.1.2 This standard does not purport to address
5、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:2D 4509 Test Method
6、s for Determining the 24-Hour Gas(AIR) Space Acetaldehyde Content of Freshly Blown PETBottles3E 691 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 r
7、equire no specialcomment.4. Summary of Test Method4.1 A specified size (800 to 1000 m) of granulated sampleis weighed into a 20-mL head-space vial, sealed, and thenheated at 150C for 60 min. After heating, the gas above thesealed sample of PET polymer is injected onto a capillary GCcolumn. The aceta
8、ldehyde is separated, and the ppm ofacetaldehyde is calculated.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 trappe
9、d 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 co
10、nditions 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 handle
11、dcarefully to avoid sample loss during the calibration procedure.Storing the standard vials in a refrigerator is a must tominimize 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 and desorp-tion, producing a
12、 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.6.5 Samples submitted for “residual AA measurement”should be stored in a freezer until they are tested. Failure to doso can re
13、sult in lower than expected results.1This test method is under the jurisdiction of ASTM Committee F02 on FlexibleBarrier Materials and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition approved April 1, 2005. Published September 2005. Originallyapproved
14、 in 2000 as published as F 201300. Last previous edition approved in2001 as F 201301.2For 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
15、page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.6 Excessive grinding of samples can cause residual AAcontained therein to be desorbed. Extensive excessive grindingcan lead to actual melting of the
16、 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.7.2 Integrator.7.3 Head-Space Sampler.7.4 Column, 30-m by 0.53-mm inside diameter (megaborecapillary column).7.5 Vials, 20-mL, head-
17、space, with 20-mm septa, 20-mmaluminum caps, and crimper for 20-mm caps.7.6 Crimper, 20-mm.7.7 Decrimper, 20-mm.7.8 Wiley Mill, equipped with an 800 to 1000-m screen, orequivalent.7.9 Syringe, calibrated, with certificate of calibration.7.10 Small Vacuum Cleaner, with hose attachment forcleaning.7.1
18、1 Analytical Balance, capable of accurately weighing toat least 60.0001 g.7.12 Hammer.8. Reagents and Materials8.1 Acetaldehyde (AA), 500 ppm AA in water (or 1000ppm), purchased certified standard.8.2 Liquid Nitrogen, plant grade (R-3, S-3).9. Calibration and StandardizationNOTE 1The following proce
19、dure should be performed and recordedonce every three months.9.1 Break open a certified AA standard ampule (ampulesmust be stored in a refrigerator) or prepare AA standard by theattached supplemental procedure. (See Appendix X5.)9.2 Using the syringe, fill it by placing the tip in the liquidstandard
20、 and quickly moving the plunger up and down severaltime to evacuate any bubbles, then pull the plunger back pastthe 2.000-L mark to 2.200 to 2.250 L.9.3 Wipe the syringe needle with a tissue.9.4 Depress the plunger until the digital readout is 2.000 L.9.5 Smear the excess liquid that is on the syrin
21、ge tip on theOUTSIDE of the headspace vial.9.6 Place the syringe inside of the vial so that the tip justtouches the bottom of the vial.9.7 Quickly inject the liquid standard into the vial and swirlthe syringe tip around the inside of the vial to smear all liquidon the vial walls.9.8 Remove the syrin
22、ge and IMMEDIATELY cap the vial.9.9 Calculate the weight of AA based on the standardscertified value and a 2.000-L injection volume.NOTE 2Acetaldehyde is very volatile. The AA ampules must bestored in a refrigerator, and the standards prepared immediately afterbreaking open an ampule.9.10 Analyze th
23、e working standard by the procedure de-scribed in Section 11, starting with 11.2.11.9.11 Calculate an AA response factor for the standard usingthe following equation:response factor of AA 5 Wt of AA in g/area of AA (1)NOTE 3Due to the error associated with the certified standard,9.1-9.11 should be p
24、erformed five times using five different standardampules.9.12 Average the five response factors obtained, and use thisvalue for the sample analyses.9.13 Manually enter the calculated response factor in thecalibration list of the integrator or data system.NOTE 4During a series of sample analyses, a p
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