ASTM_D_4053_-_98_2003.pdf

Designation:D 4053 98(Reapproved 2003)An American National StandardStandard Test Method forBenzene in Motor and Aviation Gasoline by InfraredSpectroscopy1This standard is issued under the fixed designation D 4053;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the percentbenzene in full-range gasoline.It is applicable to concentra-tions from 0.1%to 5 volume%.1.2 The values in SI units are regarded as the standard.1.3 This test method has not been validated for gasolinescontaining oxygenates.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.For specific hazardstatements,see Section 8 and 9.1.2.Referenced Documents2.1 ASTM Standards:2D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE 131 Terminology Relating to Molecular SpectroscopyE 932 Practice for Describing and Measuring Performanceof Dispersive Infrared SpectrophotometersE 1421 Practice for Describing and Measuring Performanceof Fourier Transform Mid-Infrared(FT-MIR)Spectrom-eters:Level Zero and Level One Tests3.Terminology3.1 Definitions:3.1.1 Definitions of terms and symbols relating to absorp-tion spectroscopy in this test method shall conform to Termi-nology E 131.Terms of particular significance are the follow-ing:3.1.2 absorbance,A,nthe molecular property of a sub-stance that determines its ability to take up radiant power,expressed by:A 5 log101/T!5 2log10T(1)whereT=the transmittance as defined in 3.1.5.3.1.3 radiant energy,nenergy transmitted as electromag-netic waves.3.1.4 radiant power,P,nthe rate at which energy istransported in a beam of radiant energy.3.1.5 transmittance,T,nthe molecular property of asubstance that determines its transportability of radiant power,expressed by:T 5 P/Po(2)where:P=the radiant power passing through the sample,andPo=the radiant power incident upon the sample.4.Summary of Test Method4.1 A sample of gasoline is examined by infrared spectros-copy and,following a correction for interference,comparedwith calibration blends of known benzene concentration.Fromthis comparison the amount of benzene in the gasoline isdetermined.5.Significance and Use5.1 Benzene is classed as a toxic material.A knowledge ofthe concentration of this compound may be an aid in evaluatingthe possible health hazard to persons handling and using thegasoline.This test method is not intended to evaluate suchhazards.6.Interferences6.1 Toluene and heavier aromatic compounds have someinterference in this test method.In order to minimize the effectof such interference,this test method includes a procedure thatcorrects for the error caused by the presence of toluene.Errordue to other sources of interference may be partially compen-sated for by calibrating with gasoline stocks containing little or1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarbon Analysis.Current edition approved Nov.1,2003.Published November 2003.Originallyapproved in 1981.Last previous edition approved in 1998 as D 405398.2For 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.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.no benzene but which otherwise are similar in aromatic contentto the samples to be analyzed.7.Apparatus7.1 Absorption Cell,sealed.Windows of potassium bromideor other material having sufficient transmittance out to 440cm1(22.73 m),in a cell having TFE-fluorocarbon plugs andnominal path length of 0.025 mm known to three significantnumbers.7.2 Clear Reference BlockA block made from the samematerial as cell windows for use in the reference beam path ofa double-beam spectrometer.7.3 Infrared Spectrometer,double-beam or single-beam,suitable for recording accurate measurements between 690cm1(14.49 m)and 440 cm1(22.73 m).Refer to PracticesE 932 and E 1421.NOTE1Absorbances for the bands specified in this test method areexpected to fall within the linear operating range of modern spectrometersfor the concentration range as defined.8.Reagents8.1 Benzene,spectroscopic or research grade.(WarningPoison,carcinogen,harmful,or fatal if swallowed.Extremelyflammable.)8.2 Toluene,spectroscopic or research grade.(WarningFlammable,harmful if inhaled.)8.3 Isooctane(2,2,4-trimethylpentane)