ASTM_D_7882_-_13.pdf

Designation:D788213Standard Test Method forDetermination of 4-Carboxybenzaldehyde and p-Toluic Acidin Purified Terephthalic Acid by Capillary Electrophoresiswith Normal Voltage Mode1This standard is issued under the fixed designation D7882;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 Thistestmethodcoversthedeterminationof4-carboxybenzaldehyde(4-CBA)and p-toluic acid(p-TOL)inpurified terephthalic acid(PTA)by capillary electrophoresis(CE)with normal voltage mode and UV detection.It isapplicable for 4-CBAfrom 5 to 400 mg/kg and for p-TOLfrom10 to 400 mg/kg,respectively.1.2 In determining the conformance of the test results usingthis method to applicable specifications,results shall berounded off in accordance with the rounding-off method ofPractice E29.1.3 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 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:2D1193 Specification 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 SpecificationsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Document:3EN ISO 8213 Chemical Products for Industrial UseSampling TechniquesSolid Chemical Products in theForm of Particles Varying from Powders to Coarse Lumps2.3 Other Document:4OSHA Regulations 29 CFR paragraphs 1910.1000 and1910.12003.Terminology3.1 Definitions of Terms Specific to Normal Voltage Mode inthis Standard:3.1.1 capillary electrophoresis,nan electrophoretic tech-nique in which a sample is introduced into a 50 to 100 m i.d.fused-silica capillary filled with electrolyte solution and sub-jected to high voltage for separation.3.1.1.1 DiscussionNormal voltage,with the anode on theinjection side and the cathode on the detection side,is appliedacross the capillary causing electrolyte and analytes to migratetowards the cathode and through the capillarys UV detectorwindow.Analytes are separated based on the differential ratesof migration in the electric field.Analyte detection andquantitation are based on the principles of UV detection.3.1.2 electrolye,na combination of a buffer reagent and anion-pair reagent dissolved in an aqueous solution and placedinside the capillary,used as a carrier for the analytes.3.1.3 electroosmotic flow(EOF),nthe directional velocityof electrolyte-solution flow within the capillary under anapplied voltage;the velocity and direction of flow are deter-mined by electrolyte chemistry,capillary-wall chemistry,andapplied voltage(see Fig.1).1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.02 on Oxygenated Aromatics.Current edition approved Aug.15,2013.Published October 2013.DOI:10.1520/D7882-13.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol 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 3.1.4 electropherogram,na graphical presentation of UVdetector response versus time of analysis;the x-axis is migra-tion time,which is used to identify the analyte qualitatively,and the y-axis is UV response,which can be converted to peakarea or height for quantitation.3.1.5 electrophoretic mobility,nthe specific velocity of achargedanalyteintheelectrolyteunderspecificelectroosmotic-flow conditions.3.1.5.1 DiscussionThe mobility of an analyte is directlyrelated to the analytes equivalent ionic conductance andapplies voltage,and is the primary mechanism of separation.3.1.6 hydrodynamic sampling,na sample introductiontechnique in which the injection side of the capillary withelectrolyte is immersed into sample solution and then a positivepressure differen