1、Designation: D4626 95 (Reapproved 2015)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 asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of the
5、safety 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 for Analys
6、is 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 Alkyd Res-ins
7、 (Withdrawn 2004)3D3329 Test Method for Purity of Methyl Isobutyl Ketone byGas ChromatographyD3362 Test Method for Purity of Acrylate Esters by GasChromatography (Withdrawn 2011)3D3465 Test Method for Purity of Monomeric Plasticizers byGas ChromatographyD3545 Test Method for Alcohol Content and Puri
8、ty ofAcetate Esters by Gas ChromatographyD3695 Test Method for Volatile Alcohols 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 Term
9、s 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 calculation
10、 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 combined in an
11、 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 suitable.The quanti
12、tative blends are analyzed, in 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 peakheight measurements, mass or volume response or relativeresponse factors for each bl
13、end component are calculated.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-mittee D02.04.0L on Gas Chromatography Methods.Current edition approved April 1, 2015. Published June 2015. Origin
14、allyapproved in 1986. Last previous edition approved in 2010 as D4626 95 (2010).DOI: 10.1520/D4626-95R15.2For 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 standar
15、ds Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D02-1200.Copyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. 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. Freque
17、ntly, minimal information isgiven 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
18、 calculating response factors,as 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
19、practiceare “multipliers” and prior 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 m
20、ay be caused byvariations in instrument 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 other
21、detector may be used that meets the performance requirementsof the method for which calibration is being performed.6.2 RecorderA recording potentiometer with a full-scaleresponse time of 1 s or less may be used.6.3 Integrator or ComputerMeans must be provided fordetermining the detector response. Pe
22、ak heights or areas can bemeasured by 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 C
23、olumnAny column may be used that will satisfacto-rily 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 Apparat
24、usThe specific equipmentrequired to prepare 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
25、are required forflame ionization detectors.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 relativelynonvolatile, miscible with all sample components and,preferably, well res
26、olved chromatographically from all mixturecomponents. 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 E2
27、60 for specific instructions.Condition 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 th
28、e components and concen-trations expected 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
29、 Practice D4307.8.3 Blend AnalysisAnalyze 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, usingth
30、e same measurement technique that 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 (wei
31、ght) basis as follows:RM5 M/A (1)where:RM= mass (weight) response factor for a specific n-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 3Fo
32、r purposes of this model calculation 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-paraffin ofcarbon number NRM(CN) = mass (weight) response factor for a specific n-paraffin ofcarbon number N determi
33、ned in 9.1, g/unitD4626 95 (2015)2RM(C7) = mass (weight) response factor for a n-heptane determinedin 9.1, g/unit9.2 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
34、 n-paraffin in the blend, mL, andA = 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 fo
35、r a specific n-paraffinof carbon number N determined in 9.2, mL/unit,andRV(C7) = volume response factor for n-heptane determinedin 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
36、 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 riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible t
37、echnical committee and must be reviewed 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 conside
38、ration at a meeting of theresponsible 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
39、 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 95 (2015)3
