1、Designation: D 4626 95 (Reapproved 2005)Designation: 378/87An American National StandardStandard Practice forCalculation of Gas Chromatographic Response Factors1This standard is issued under the fixed designation D 4626; the number immediately following the designation indicates the year oforiginal
2、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 practice covers a procedure for calculating gaschromatographic
3、 response factors. It is applicable 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
4、react in the chromatograph or are 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 standa
5、rd 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 AST
6、M Standards:2D 2268 Test Method for Analysis of High-Purity n-Heptaneand Isooctane by Capillary Gas ChromatographyD 2427 Test Method for Determination of C2Through C5Hydrocarbons in Gasolines by Gas ChromatographyD 2804 Test Method for Purity of Methyl Ethyl Ketone byGas ChromatographyD 2998 Test Me
7、thod for Polyhydric Alcohols in AlkydResins3D 3329 Test Method for Purity of Methyl Isobutyl Ketoneby Gas ChromatographyD 3362 Test Method for Purity of Acrylate Esters by GasChromatographyD 3465 Practice for Purity of Monomeric Plasticizers byGas ChromatographyD 3545 Test Method for Alcohol Content
8、 and Purity ofAcetate Esters by Gas ChromatographyD 3695 Test Method for Volatile Alcohols in Water byDirect Aqueous-Injection Gas ChromatographyD 4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsE 260 Practice for Packed Column Gas Chromatography3. Terminology3.1 Definit
9、ions of Terms Specific to This Standard:3.1.1 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
10、 calculation formula, theresponse factor (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 co
11、mbined in an inert, tight-sealing glass vial. 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 suitabl
12、e.The quantitative blends are analyzed, in duplicate, by gaschromatography using either thermal conductivity, flame-ionization or other forms of detection. From the mass or1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibil
13、ity of Subcommittee D02.04 onHydrocarbon Analysis.Current edition approved May 1, 2005. Published May 2005. Originallyapproved in 1986. Last previous edition approved in 2000 as D 4626 95 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
14、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D02-1200.1Copyright ASTM Internati
15、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.volume composition of the blend and the raw area or peakheight measurements, mass or volume response or relativeresponse factors for each blend component are calculated.5. Significance and Use5.1 ASTM standard
16、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 in these methods on the practice of calculating calibra-tion or response factor
17、s. Test Methods D 2268, D 2427,D 2804, D 2998, D 3329, D 3362, D 3465, D 3545, andD 3695 are examples. The present practice helps to fill thisvoid by providing a detailed reference procedure for calculat-ing response factors, as exemplified by analysis of a standardblend of C6to C11n-paraffins using
18、 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 prior to final calculation of the results thearea obtained for each compoun
19、d 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 instrument design, columns, and experimentaltechniques. It is necessary that
20、 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 the performance requirementsof the method for which calibration is being
21、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 computer, electronic integration or manual tech-niques.NOTE 1Rapidly el
22、uting 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 satisfac-torily separate the compounds of interest, including the solve
23、nt,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 prepare liquid blends is described in Test MethodD 4307.7. Reagents and M
24、aterials7.1 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 detectors.7.3 n-Paraffn Hydrocarbons,C6,C7,C8,C9,C10,C11, andC12-99 % pure.
25、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 mixture compo-nents. In this model, n-C12is used.8. Procedure8.1 Instrum
26、ent 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 E 260 for specific instructions.Condition the columns at their required operating temperatureuntil a stable
27、 baseline is established at the required sensitivity.8.2 Calibration BlendsPrepare appropriate calibrationblends as described in Practice D 4307. The blends shouldresemble as closely as possible the components and concen-trations expected in the test sample to be analyzed, becauseresponse factors ma
28、y not be linear over large concentrationranges.NOTE 2For volume response factors, volumetric concentrations arecalculated from gravimetric concentrations using component densities inaccordance with Practice D 4307.8.3 Blend AnalysisAnalyze each prepared blend in dupli-cate using chromatographic cond
29、itions 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 is to be used for testsamples. Where electronic integration or a com
30、puter 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)where:RM= mass (weight) response factor for a specificn-paraffin, g/u
31、nitM = 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 calculation n-heptane has beenchosen as the standard reference compound.RRMCN
32、! 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 (weight) response factor for a n-heptane deter-mined in 9.1, g/unitD 4
33、626 95 (2005)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 = area or peak height of the specific n-paraffin peak,units.9.2.1
34、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 number N determined in9.2, mL/unit, andRV(C7) = volume response fact
35、or 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 standard. Users of this standard are expressly advised that determi
36、nation of the validity of any such patent rights, and the 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 wi
37、thdrawn. 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 theresponsible technical committee, which you may attend. If you feel that y
38、our 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 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).D 4626 95 (2005)3
