1、Designation: D 4053 04An 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 cas
2、e 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*1.1 This test method covers the determination of the percentbenzene in full-range gasoline. I
3、t is applicable to concentra-tions from 0.1 % to 5 volume %.1.2 This test method has not been validated for gasolinescontaining oxygenates. Certain oxygenates interfere with themeasurement described in this test method. Test MethodD 6277 is recommended for gasolines containing oxygenates.1.3 The val
4、ues in SI units are regarded as the standard.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 regula
5、tory limitations prior to use. For specificwarning statements, see Section 8 and 9.1.2. Referenced Documents2.1 ASTM Standards:2D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 6277 Test Method for Determination of Benzene inSpark-Ignition Engine Fuels Using Mid Infrared Spect
6、ros-copyE 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 Test
7、s3. 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 abi
8、lity to take up radiant power,expressed by:A 5 log101/T! 52log10T (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,
9、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 spec
10、tros-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 co
11、mpound 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 suc
12、h interference, this test method includes a procedure that1This 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, 2004. Published November 200
13、4. Originallyapproved in 1981. Last previous edition approved in 2003 as D 405398(2003).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 Summa
14、ry page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.corrects for the error caused by the presence of toluene. Errordue to other sources of inter
15、ference may be partially compen-sated for by calibrating with gasoline stocks containing little orno 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 trans
16、mittance 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 Spect
17、rometer, 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.NOTE 1Absorbances for the bands specified in this test method areexpected to fall within the linear operating range of modern spectrometer
18、sfor 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)
19、 or n-Heptane, spec-troscopic or research grade. (WarningIsooctane andn-Heptane are extremely flammable, harmful if inhaled.)9. Sampling9.1 Follow the procedures and precautions contained inPractice D 4057.(WarningGasolines are extremely flam-mable, harmful if inhaled.)9.2 Cool the sample container
20、and contents to 0 to 4Cbefore opening the container and transferring material to othercontainers.10. Calibration and Standardization10.1 Reference StandardsPrepare standard blends of ben-zene, using fresh, full-range gasoline of low benzene content(less than 1 volume %) as the solvent. Measure and d
21、ilute allcomponents at ambient temperature. Accurately pipet therequired volume of benzene into 100-mL volumetric flaskspartially filled with the gasoline. Dilute to volume withadditional gasoline. Prepare the blends in 1 volume % incre-ments.10.2 Toluene StandardPrepare a blend of toluene in either
22、isooctane or n-heptane as the solvent. Measure and dilute allcomponents at ambient temperature. Accurately pipet 2 mL oftoluene into a 10-mL volumetric flask partially filled witheither isooctane or n-heptane. Dilute to volume with the chosensolvent.10.3 Calibration:10.3.1 Following the steps of Sec
23、tion 11, Procedure, foreach of the standard blends and the gasoline base stock,determine three absorbance values: (1) at the point of maxi-mum absorbance near 673 cm1(14.86 m), designated thebenzene band; (2) at the point of maximum absorbance near460 cm1(21.74 m), designated the toluene band; and (
24、3)at500 cm1(20.00 m), designated the baseline position.10.3.2 Following the steps of Section 11, Procedure, for thetoluene standard, determine the absorbances at the locationsdescribed in 10.3.1 for the benzene band, the toluene band, andthe baseline position. Subtract the baseline position value at
25、about 500 cm1from those found for benzene at about 673cm1and toluene at about 460 cm1in order to obtain the netabsorbance for each. Take the ratio of the benzene band netabsorbance to the toluene band net absorbance to obtain thetoluene correction factor.10.3.3 For the gasoline base stock and each b
26、lend examinedin 10.3.1, obtain the net absorbances at the benzene and thetoluene bands by subtracting the baseline position value fromthe absorbances found for the band maxima. Continuing, foreach liquid, multiply the toluene band net absorbance by thetoluene correction factor found in 10.3.2 and su
27、btract this valuefrom the benzene band net absorbance in order to obtain thecorrected net absorbance for the benzene band.10.3.4 Construct a curve by plotting the benzene bandcorrected net absorbance for each calibration liquid, as foundin 10.3.3, divided by the cell path length in millimetres, vers
28、usthe volume % of added benzene for each.10.3.5 Extrapolate the curve to zero absorbance. The abso-lute value of the intercept is the concentration of benzene in thegasoline used as the solvent.10.3.6 Construct a standard reference curve by replottingthe baseline absorbances per millimetre thickness
29、, corrected in10.3.5, against total concentration of benzene in percent byvolume so that the curve passes through the origin.NOTE 2A linear equation can be used instead of the plot.11. Procedure11.1 Clean the cell with isooctane or similar solvent and dryby means of a source of vacuum.11.2 Fill the
30、absorption cell with the gasoline to be tested.Both cell and sample should be at ambient temperature duringthis operation. If moisture condensation is a problem, blanketthe cell with a dry, inert atmosphere. Use care to avoidformation of air pockets in the cell and scan immediately toprevent bubbles
31、 from forming. Observe the cell during the scanperiod to check for bubble formation.11.3 Scan the infrared spectrum from 690 cm1(14.99 m)to 440 cm1(22.73 m) versus a clear reference block in thereference beam (for double-beam operation); follow the direc-tions of the manufacturer for quantitative an
32、alysis.11.4 Determine the corrected net absorbance of the benzeneband as described in 10.3.3.11.5 Divide the benzene band corrected net absorbance, asfound in 11.4, by the cell path length in millimetres.12. Calculation12.1 Calculate the benzene content of the gasoline in liquidvolume % by entering
33、the calibration curve of 10.3.6 or theequation in Note 2 with the value of the benzene band found in11.5.D405304212.2 If the results are desired on a weight basis, convert tomass %, as follows:B 5 V 3 0.8844/R (3)where:B = benzene, mass %V = benzene, volume % andR = relative density of sample, 15/15
34、C.13. Report13.1 Report numerical results to the nearest 0.1 volume %.14. Precision and Bias14.1 The precision of the test method as obtained bystatistical examination of interlaboratory results is as follows:14.1.1 RepeatabilityThe difference between successivetest results, obtained by the same ope
35、rator with the sameapparatus under constant operating conditions on identical testmaterials, would in the long run, in normal and correctoperation of the test method, exceed 0.08 volume % only inone case in twenty.14.1.2 ReproducibilityThe difference between two singleand independent results, obtain
36、ed by different operators work-ing in different laboratories on identical test material, would inthe long run, in the normal and correct operation of the testmethod exceed 0.18 volume % only in one case in twenty.14.2 BiasThere are no interlaboratory test data to estab-lish a statistical statement o
37、n bias.15. Keywords15.1 aviation gasoline; benzene; infrared spectroscopy; mo-tor gasolineSUMMARY OF CHANGESSubcommittee D02.04 has identified the location of selected changes to this standard since the last issue(D 405398(2003) that may impact the use of this standard.(1) Added Test Method D 6277 t
38、o Referenced Documents. (2) Revised 1.2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the
39、 riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of
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41、ake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D4053043
