ASTM_D_3725_-_78_1998.pdf

Designation:D 3725 78(Reapproved 1998)Standard Test Method forSemiquantitative Determination of Fish Oil in Drying Oilsand Drying Oil Fatty Acids by Gas-LiquidChromatography1,2This standard is issued under the fixed designation D 3725;the number immediately following the designation indicates the 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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination by gas-liquidchromatography of herring and menhaden fish oil when presentin small quantities in other drying oils and fatty acids.Itdescribes specific conditions required for use with Test MethodD 1983 to identify these oils.NOTE1For general information that contributes to the knowledge ofgas chromatography of fats and oils,see Guide D 555,Test MethodD 2245 and Practice E 260.1.2 This standard 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 ASTM Standards:D 555 Guide for Testing Drying Oils3D 1983 Test Method for Fatty Acid Composition by Gas-Liquid Chromatography of Methyl Esters3D 2245 Test Method for Identification of Oils and OilAcidsin Solvent-Reducible Paints4D 2800 Test Method for Preparation of Methyl Esters fromOils for Determination of Fatty Acid Composition by GasChromatography3D 3457 Test Method for Preparation of Methyl Esters fromFatty Acids for Determination of Fatty Acid Compositionby Gas-Liquid Chromatography3E 260 Practice for Packed Column Gas Chromatography53.Summary of Test Method3.1 The oil or fatty acids are converted to methyl esterswhich are then subjected to gas-liquid chromatography.Thechromatogram is examined for small amounts of acids com-mon to fish oils but not common to other drying oils or fattyacids used in paints and related products.These specific acidsare referred to as tracer acids.4.Apparatus4.1 Gas Chromatographic Instrument having the minimalfollowing characteristics:4.1.1 Column Oven operated at a constant temperaturebetween 190 and 210C.4.1.2 Sample Inlet Port,with the heater characteristicsnecessary for operation at 300C.4.1.3 Detector,of the thermal-conductivity or the flameion-ization type.4.1.4 ColumnA 12 ft(3.7 m)long by18in.(3.2 mm)indiameter aluminum column filled with 10%(DEGS)(diethyl-ene glycol succinate)on 80 to 100-mesh acid washed,calcineddiatomaceous earth is recommended.However,any combina-tion of column and packing,capable of separating these higheracids with good definition and repeatability may be utilized.5.Reagents and Materials5.1 Fish Oil or Reference Standards containing markeracids6(known acids added for identification purposes).5.2 Standard Reference Drying Oils(for example,linseed,soya,etc.)6.Standardization and Calibration6.1 Refer to Test Method D 1983.7.Procedure7.1 Preparation of Methyl Esters:7.1.1 If sample is an oil,prepare the methyl esters in1This 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 Oils.Current edition approved Sept.29,1978.Published January 1979.2This method is equivalent to or better than U.S.Federal Test MethodStandard 141,Method 5011.1,Qualitative Test for Fish Oil available from Stan-dardization Documents Order Desk,Bldg.4 Section D,700 Robbins Ave.,Philadelphia,PA 19111-5094.3Annual Book of ASTM Standards,Vol 06.03.4Annual Book of ASTM Standards,Vol 06.01.5Annual Book of ASTM Standards,Vol 14.02.6The sole source of supply of marker acids(20:5,22:1,and 22:6),known to thecommittee at this time is Nu-Check Prep Inc.,P.O.Box 172,Elysian,MN 56028.Ifyou are aware of alternative suppliers,please proved this information to ASTMHeadquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMaccordance with Test Method D 2800.7.1.2 If sample is a fatty acid,prepare the methyl esters inaccordance with Test Method D 3457.7.2 Gas Chromatographic Separation:7.2.1 Determine optimum conditions required for goodseparation of methyl esters on the chromatograph and columnbeing utilized.A 300C injection port temperature isrecommended for good reproducible identification of acidsbeyond C18.It is recommended that the range of theinstrument be expanded to produce 103 magnification of thepeak areas of fatty acids beyond C18 occurring ascontaminants in drying oils.7.2.2 Subject the prepared methyl es