1、Designation:D788313Standard Test Method forDetermination of 4-Carboxybenzaldehyde and p-Toluic Acidin Purified Terephthalic Acid by Weak Anion Exchange HighPerformance Liquid Chromatography1This standard is issued under the fixed designation D7883;the number immediately following the designation ind
2、icates 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 method2covers the determination of the
3、4-Carboxybenzaldehyde(4-CBA)and p-Toluic acid(p-TOL)in purified terephthalic acid(PTA)by weak anion exchangehigh performance liquid chromatography(HPLC).Thismethod is applicable for 4-CBA from 2 to 500 mg/kg and forp-TOL from 10 to 500 mg/kg,respectively.1.2 In determining the conformance of the tes
4、t results usingthis method to applicable specification,results shall be roundedoff in accordance with the rounding-off method of PracticeE29.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport t
5、o 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:3D1193 Specif
6、ication for Reagent WaterD4790 Terminology of Aromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE1
7、77 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE682 Practice for Liquid Chromatography Terms and Rela-tionshipsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Document:4EN ISO 8213 Chemical products for industrial useSam
8、pling techniquesSolid chemical products in theform of particles varying from powders to coarse lumps2.3 Other Document:5OSHA Regulations,29 CFR paragraphs 1910.1000 and1910.12003.Summary of Test Method3.1 Weak Anion Exchange HPLC MethodPTA sample isdissolved in ammonium hydroxide solution.After pHad
9、justment,a fixed volume of this solution is injected into ahigh performance liquid chromatograph equipped with a UVdetector.An anion-exchange column is used to separate theimpurities 4-CBAand p-TOL from PTA.The external standardcalibration is used for quantification.4.Significance and Use4.1 The pre
10、sence of 4-CBA and p-TOL in PTA used for theproduction of polyester is undesirable because they can slowdown the polymerization process,and 4-CBAis also impartingcoloration to the polymer due to thermal instability.4.2 Determining the amount of 4-CBA and p-TOL remain-ing from the manufacture of PTA
11、is often required.This testmethod is suitable for setting specifications and could be usedas an internal quality control tool where these products areproduced or are used.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct
12、 responsibility ofSubcommittee D16.02 on Oxygenated Aromatics.Current edition approved Aug.1,2013.Published October 2013.DOI:10.1520/D7883-13.2This standard is based on SH/T 1612.7-1995 Purified terephthalic acid forindustrial usedetermination of p-Toluic Acid,4-Carboxybenzaldehyde-HPLC,copyright SI
13、NOPEC,22 Chaoyangmen North Street,Chaoyang District,Beijing,China 100728.A copy of SH/T 1612.7-1995 may be obtained from ChinaPetrochemical Press,www.sinopec-.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTM
14、Standards volume information,refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.5Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capit
15、ol St.,NW,Mail Stop:SDE,Washington,DC 20401,http:/www.access.gpo.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Apparatus5.1 High Performance Liquid Chromatograph(HPLC)any HPLC capable of pumping the mobile phase at flow ratesbetwe
16、en 0.1 and 2.0 mL/min,with a pressure between 0 and 40MPa and a pulsation of less than 1%full scale deflection underthe test conditions described in Table 1.The S/N(signal tonoise)ratio should be 3:1 or greater for 2 mg/kg 4-CBAand 10mg/kg p-TOL.5.2 Sample Injection Systemcapable of injecting 1 to 25L,using either partial or full loop mode,with a repeatabilityof 61%.5.3 Detector,Variable Wavelength Ultraviolet PhotometricDetector(VWD),Multi-wavelength Detector,or PhotometricDiode Array Detector(
