1、Designation: D4626 95 (Reapproved 2010)Designation: 378/87Standard Practice forCalculation of Gas Chromatographic Response Factors1This standard is issued under the fixed designation D4626; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 practice covers a procedure for calculating gaschromatographic response factors. It is applica
3、ble to chromato-graphic data obtained from a gaseous mixture or from anymixture of compounds that is normally liquid at room tempera-ture and pressure or solids, or both, that will form a solutionwith liquids. It is not intended to be applied to those com-pounds that react in the chromatograph or ar
4、e not quantitativelyeluted. Normal C6through C11paraffins have been chosen asmodel compounds for demonstration purposes.1.2 The values stated in SI units are to be regarded as thestandard. The values stated in inch-pound units are for infor-mation only.1.3 This standard does not purport to address a
5、ll 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:2D2268 Test Method f
6、or Analysis of High-Purity n-Heptaneand Isooctane by Capillary Gas ChromatographyD2427 Test Method for Determination of C2through C5Hydrocarbons in Gasolines by Gas ChromatographyD2804 Test Method for Purity of Methyl Ethyl Ketone ByGas ChromatographyD2998 Test Method for Polyhydric Alcohols in Alky
7、dResins3D3329 Test Method for Purity of Methyl Isobutyl Ketoneby Gas ChromatographyD3362 Test Method for Purity of Acrylate Esters by GasChromatographyD3465 Test Method for Purity of Monomeric Plasticizers byGas ChromatographyD3545 Test Method for Alcohol Content and Purity ofAcetate Esters by Gas C
8、hromatographyD3695 Test Method for VolatileAlcohols in Water by DirectAqueous-Injection Gas ChromatographyD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsE260 Practice for Packed Column Gas Chromatography3. Terminology3.1 Definitions of Terms Specific to This Standard:3
9、.1.1 response factor (R)a constant of proportionalityused to convert the observed chromatographic response ofspecific compounds to either mass or volume percent compo-sition. The observed response may be measured as peak areasor peak heights. Depending on the calculation formula, theresponse factor
10、(R) is applied by either multiplying or dividingthe observed response by the determined factor.3.1.2 In this practice, the response factors determined aremultiplying factors.4. Summary of Practice44.1 Individual C6to C11n-paraffins are precisely weighedand combined in an inert, tight-sealing glass v
11、ial. Differentconcentration levels of the blend components to cover concen-tration ranges of interest may be obtained by dilution with asuitable solvent. As diluent, a n-paraffin, such as n-dodecane,that is, higher boiling than the blend components is suitable.The quantitative blends are analyzed, i
12、n duplicate, by gaschromatography using either thermal conductivity, flame-ionization or other forms of detection. From the mass orvolume composition of the blend and the raw area or peak1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the dir
13、ect responsibility of Subcommittee D02.04.0Lon Gas Chromatography Methods.Current edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1986. Last previous edition approved in 2005 as D462695(2005).DOI: 10.1520/D4626-95R10.2For referenced ASTM standards, visit the ASTM websit
14、e, 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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Supporting data ha
15、ve been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D02-1200.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.height measurements, mass or volume response or relativeresponse factors f
16、or each blend component are calculated.5. Significance and Use5.1 ASTM standard gas chromatographic methods for theanalysis of petroleum products require calibration of the gaschromatographic system by preparation and analysis of speci-fied reference mixtures. Frequently, minimal information isgiven
17、 in these methods on the practice of calculating calibra-tion or response factors. Test Methods D2268, D2427, D2804,D2998, D3329, D3362, D3465, D3545, and D3695 are ex-amples. The present practice helps to fill this void by providinga detailed reference procedure for calculating response factors,as
18、exemplified by analysis of a standard blend of C6to C11n-paraffins using n-C12as the diluent.5.2 In practice, response factors are used to correct peakareas to a common base prior to final calculation of the samplecomposition. The response factors calculated in this practiceare “multipliers” and pri
19、or to final calculation of the results thearea obtained for each compound in the sample should bemultiplied by the response factor determined for that com-pound.5.3 It has been determined that values for response factorswill vary with individual installations. This may be caused byvariations in inst
20、rument design, columns, and experimentaltechniques. It is necessary that chromatographs be individuallycalibrated to obtain the most accurate data.6. Apparatus6.1 ChromatographAny gas chromatograph equippedwith either a flame ionization, thermal conductivity or otherdetector may be used that meets t
21、he performance requirementsof the method for which calibration is being performed.6.2 RecorderA recording potentiometer with a full-scaleresponse time of1sorless may be used.6.3 Integrator or ComputerMeans must be provided fordetermining the detector response. Peak heights or areas can bemeasured by
22、 computer, electronic integration or manual tech-niques.NOTE 1Rapidly eluting peaks such as those produced by a capillarycolumn are difficult to accurately measure manually. Therefore, peaks ofthis type must be measured by computer or electronic integration.6.4 ColumnAny column may be used that will
23、 satisfac-torily separate the compounds of interest, including the solvent,if used.6.5 Sample IntroductionSample introduction may be bymeans of a constant volume liquid sample valve or by injectionwith a microsyringe through a septum.6.6 Blend Preparation ApparatusThe specific equipmentrequired to p
24、repare liquid blends is described in Test MethodD4307.7. Reagents and Materials7.1 Carrier Gas, helium, hydrogen, or other suitable gasesmay be used depending on the detector and the requirements ofthe method being calibrated.7.2 Combustion GasesAir and hydrogen are required forflame ionization dete
25、ctors.7.3 n-Paraffn Hydrocarbons,C6,C7,C8,C9,C10,C11, andC12-99 % pure.7.4 Solvent, used as a diluent to vary concentrations of blendcomponents. A suitable solvent is one that is relatively non-volatile, miscible with all sample components and, preferably,well resolved chromatographically from all m
26、ixture compo-nents. In this model, n-C12is used.8. Procedure8.1 Instrument PreparationInstall the chromatographiccolumns and establish the flow rates and operating tempera-tures as specified in the method for which calibration is beingperformed. Refer to Practice E260 for specific instructions.Condi
27、tion the columns at their required operating temperatureuntil a stable baseline is established at the required sensitivity.8.2 Calibration BlendsPrepare appropriate calibrationblends as described in Practice D4307. The blends shouldresemble as closely as possible the components and concen-trations e
28、xpected in the test sample to be analyzed, becauseresponse factors may not be linear over large concentrationranges.NOTE 2For volume response factors, volumetric concentrations arecalculated from gravimetric concentrations using component densities inaccordance with Practice D4307.8.3 Blend Analysis
29、Analyze each prepared blend in dupli-cate using chromatographic conditions and injection techniquethat are identical to those used for test samples.8.4 Peak MeasurementsDetermine the peak height or areaof each n-paraffin in the blend, excluding n-C12diluent, usingthe same measurement technique that
30、is to be used for testsamples. Where electronic integration or a computer is used,the various integration parameters must be the same foranalysis of the blends and for the test samples.9. Calculation9.1 Calculate the response factor for each n-paraffin on amass (weight) basis as follows:RM5 M/A (1)w
31、here:RM= mass (weight) response factor for a specificn-paraffin, g/unitM = mass (weight) of a specific n-paraffin in the blend, g,andA = area or peak height of the specific n-paraffin peak,units.9.1.1 Calculate the mass relative response factors as fol-lows:NOTE 3For purposes of this model calculati
32、on n-heptane has beenchosen as the standard reference compound.RRMCN! 5 RMCN!/RMC7! (2)where:RRM(CN) = mass (weight) relative response factor for a n-paraffinof carbon number NRM(CN) = mass (weight) response factor for a specific n-paraffinof carbon number N determined in 9.1, g/unitRM(C7) = mass (w
33、eight) response factor for a n-heptane deter-mined in 9.1, g/unitD4626 95 (2010)29.2 Calculate the response factor for each n-paraffin on avolume basis as follows:RV5 V/A (3)where:RV= volume response factor for a specific n-paraffin,mL/unit,V = volume of the specific n-paraffin in the blend, mL,andA
34、 = area or peak height of the specific n-paraffin peak,units.9.2.1 Calculate the volume response factors as follows:RRVCN! 5 RVCN!/RVC7! (4)where:RRV(CN) = volume relative response factor for a specificn-paraffin of carbon number N,RV(CN) = volume response factor for a specificn-paraffin of carbon n
35、umber N determined in9.2, mL/unit, andRV(C7) = volume response factor for n-heptane deter-mined in 9.2, mL/unit.10. Keywords10.1 gas chromatography; response factorASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this
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37、eviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of therespon
38、sible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake 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
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