1、Designation:D 1983 90(Reapproved 1995)e1An American National StandardStandard Test Method forFatty Acid Composition by Gas-Liquid Chromatography ofMethyl Esters1This standard is issued under the fixed designation D 1983;the number immediately following the designation indicates the year oforiginal a
2、doption 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.This standard has been approved for use by agencies of the Department of Defense.e1NOT
3、EUnit of measurement statement added editorially in May 1995.1.Scope1.1 This test method establishes standard conditions for theseparation and identification of methyl esters by gas-liquidchromatography.1.2 This test method is applicable to animal and vegetablefatty acids and oils having 8 to 24 car
4、bon atoms.The use of thepolyester liquid phase facilitates the separation of both thesaturated and various unsaturated fatty acid methyl esters onthe chromatogram obtained.1.3 The conditions specified in this test method are notsuitable for determining epoxy and oxidized fatty acids nor tofatty acid
5、s that have been polymerized.See also Test MethodsD 2800 and D 3457.1.4 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is
6、 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:D 2800 Test Method for Preparation of Methyl Esters fromOils for Determination of Fat
7、ty Acid Composition byGas-Liquid Chromatography2D 3457 Test Method for Preparation of Methyl Esters fromFatty Acids for Determination of Fatty Acid Compositionby Gas-Liquid Chromatography23.Significance and Use3.1 This test method provides a means for identifyingvegetable oils as to type by comparin
8、g to known standards.Itcan also be used to detect adulteration of one vegetable oil byanother.3.2 The amount or the proportion of one specific acid can beused for specification purposes,for example,the amount oflinolenic acid in linseed oil or the percent of linoleic acid insunflower oil.3.3 By meas
9、uring the amount of total eluted acids by use ofan internal standard,an estimation may be made of the amountof polymerization of the fatty acids present in a polymerizedoil.4.Apparatus4.1 Gas Chromatographic Instrument having the followingminimal characteristics:4.1.1 Column Oven,operated at a const
10、ant temperaturebetween 190 and 210C.4.1.2 Sample Inlet Port,with the heater characteristicsnecessary for operation at 60C higher than the maximumnecessary column oven temperature.4.1.3 Detector,of the flame ionization or thermal conduc-tivity type.If separately thermostatted,it should be maintaineda
11、t column temperature or hotter.4.1.4 Column,1.5 to 3.0 m(5 to 10 ft)long,6.4 mm(14in.)in outside diameter,made of glass,stainless steel,copper,oraluminum packed with 20 weight%of polydiethylene glycolsuccinate polyester(DEGS)liquid phase on 80 to 100 meshacid washed calcined diatomaceous earth.34.1.
12、5 Recorder,0 to 1-mV range,1-s full-scale deflectionwith a chart speed of 13 to 25 mm(12to 1 in.)/min,and anattenuator switch to change the recorder range as required;therecorder should be equipped with an integrator if possible.4.1.6 Helium Carrier Gas,pure.1This method is under the jurisdiction of
13、 ASTM Committee D-1 on Paint andRelated Coatings,Materials,and Applications,and is the direct responsibility ofSubcommittee D01.32 on Drying Oils.Current edition approved May 25,1990.Published July 1990.Originallypublished as D 1983 64 T.Last previous edition D 1983 75(1980)e1.2Annual Book of ASTM S
14、tandards,Vol 06.03.3Chromosorbs W and P manufactured by Manville Sales Corp.,available fromgas chromatography suppliers,have been found satisfactory for this purpose.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standa
15、rds.Copyright ASTM4.2 Syringe for Injecting Specimens,fixed needle,10-Lcapacity or equivalent with a known and reproducible volume.4.3 Electronic or Mechanical Integrator.5.Reagents5.1 Standard Fatty Acid Methyl Ester containing approxi-mately equal quantities of oleic and stearic methyl esters,foro
16、ptimizing operating conditions.6.Preparation of Apparatus6.1 Start the flow of helium gas through the apparatus andadjust the inlet port,column,and detector,if individuallythermostatted,to their operating conditions as given in 4.1.Record a base line to check for stability of the instrument.Normally a new column with the DEGS liquid phase must bepreconditioned by maintaining it at its operating temperaturewith helium flowing through it for 24 h or until the recorderbase line is stable at the mos