1、Designation:D 3457 87(Reapproved 1991)e1Standard Test Method forPreparation of Methyl Esters From Fatty Acids forDetermination of Fatty Acid Composition by Gas-LiquidChromatography1This standard is issued under the fixed designation D 3457;the number immediately following the designation indicates t
2、he year oforiginal 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.e1NOTEKeywords were added editorially in August 1991.1.Scope1.1 Th
3、is test method covers a procedure for conversion ofanimal and vegetable fatty acids into methyl esters of the fattyacids suitable for analysis by gas-liquid chromatography.1.2 This test method is applicable to animal and vegetablefatty acids having 8 to 24 carbon atoms.1.3 This standard does not pur
4、port to address all of thesafety problems,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.For specific hazardstatements,see 6.4 and Note 1
5、.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 1983 Test Method for Fatty Acid Composition by Gas-Liquid Chromatography of Methyl Esters33.Summary of Test Method3.1 This test method is based upon esterification of fattyacids with methanol,using boron trifluoride a
6、s catalyst.Themethyl esters are extracted with ethyl ether and recovered byevaporation of the ether.3.2 An internal standard may be added if certain constitu-ents are considered likely to be present(see Section 7).4.Significance and Use4.1 This test method provides a means by which animal orvegetabl
7、e fatty acids are converted into their correspondingmethyl esters so that the fatty acids can then be analyzed by theuse of Test Method D 1983.5.Apparatus5.1 Separatory Funnels,125 and 60-mL with TFE-fluorocarbon stopcocks.5.2 Powder Funnel,wide stem.5.3 Erlenmeyer Flasks,2-L and 25-mL capacity.5.4
8、Glass-Stoppered Storage Bottles for BF3-methanol,500-mL capacity or as required.5.5 Platform Balance,5-kg capacity;smallest scale divi-sions required are 0.50 g.5.6 Analytical Balance,accurate to 1 mg.5.7 Steam Bath,in fume hood.5.8 Ice Bath,suitable to accommodate a 2-L Erlenmeyerflask.5.9 Glass Tu
9、bing,borosilicate glass,5-mm inside diameterfor delivery tube.6.Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests,unless otherwise specified.Unless otherwiseindicated,it is intended that all reagents shall conform to thespecifications of the Committee on A
10、nalytical Reagents of theAmerican Chemical Society,where such specifications areavailable.4Other grades may be used provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.6.2 Purity of WaterUnless otherwis
11、e indicated,referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D 1193.6.3 Boron Trifluoride,cylinder.56.4 Boron Trifluoride Reagent(125 g/L of methanol)Add1 L of methanol to a 2-L Erlenmeyer flask and weigh on abalance.Place in an ice bath and slowly b
12、ubble boron1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.32 on Drying OilsCurrent edition approved May 29,1987.Published July 1987.Originallypublished as D 3457 75.Last pre
13、vious edition D 3457 75(1980)e1.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 06.03.4Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,s
14、ee Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.5Available from the Matheson Co.,Box 966,Joliet,IL.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West
15、 Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMNOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.trifluoride(BF3)gas from a tank through a glass tube u
16、ntil 125g are taken up.This operation should be performed in a goodfume hood,and the gas should not flow so fast that white fumesemerge from the flask.The BF3must be flowing through theglass tube before it is placed in and until it is removed from themethanol,or the methanol may be drawn into the gas cylindervalve system and cause an explosion.This reagent has anexcellent shelf life and may be used up to four months frompreparation.Refrigerate it in a glass-stoppered bottle.NOTE1Warning:Handling