1、Designation:D544093(Reapproved 2009)Standard Test Method forDetermining the Melting Point of Fats and Oils1This standard is issued under the fixed designation D5440;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last rev
2、ision.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 test method is intended to determine the meltingpoint of all normal animal and vegetable fats and oils.This testmethod was der
3、ived from ALCA H-16.1.2 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 thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard t
4、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 American Leather Chemists Association Standard:ALCA H-16 Melting Point23.Significance and Use3.1 This test method is intended to determine the meltin
5、gpoint of all normal animal and vegetable fats.3.2 The natural fats and oils,that is,those of animal andvegetable origin,are mixtures of glycerides and other sub-stances and consist of a number of components.They do notexhibit either a definite or sharp melting point.Fats passthrough a stage of grad
6、ual softening before they becomecompletely liquid.The melting point then shall be defined bythe specific conditions of the method by which it is determinedand,in this case,it shall be the temperature at which the samplebecomes perfectly clear and liquid.4.Apparatus4.1 Melting Point Tubes,capillary g
7、lobe tubing,with aninside diameter of 1 mm and an outside diameter of 2 mm,max.A convenient length is 50 to 80 mm.4.2 Thermometer,2 to 68C with 0.2C divisions.4.3 Glass Beaker,600 mL.4.4 Heat Source,gas burner or electric hot plate.5.Procedure5.1 The sample shall be melted and filtered through filte
8、rpaper to remove any impurities and the last traces of moisture.The sample shall be absolutely dry.At least three cleancapillary tubes shall be dipped in the completely liquid sampleso that the fat stands approximately 10 mm high in each tube.One end of the tube(where the sample is located)shall bef
9、used in a small flame,taking care not to burn the fat.5.2 The tubes shall be placed in a beaker and held in arefrigerator at 4 to 10C overnight(16 h).5.2.1 The samples shall be completely liquid when the tubesare placed in the refrigerator.It is good practice to pass theends of the tubes containing
10、the sample momentarily throughthe flame,just before they are taken to the refrigerator.5.3 After removing the tubes from the refrigerator,theyshall be attached to the thermometer,using a rubber band orany suitable means,so that the lower ends of the melting pointtubes shall be even with the bottom o
11、f the mercury bulb of thethermometer.The thermometer shall be suspended in a 600 mLbeaker,which is about half full of clear distilled water and thebottom of the thermometer immersed approximately 30 mm.5.4 The starting bath temperature shall be adjusted to 8 to10C below the melting point of the samp
12、le at the beginning ofthe test.Agitation of the water bath shall be made with a smallstream of air or other suitable means,and heat shall be appliedso the batch temperature is increased at the rate of approxi-mately 0.5C per min.5.5 Fats usually pass through an opalescent stage beforemelting complet
13、ely.The heating shall be continued until thetubes are completely clear throughout.The temperature shallbe observed at which each tube becomes clear.5.6 The average of the melting point of all the tubes shall betaken and this average shall be reported as the melting point.6.Report6.1 Report the tempe
14、rature recorded in 5.6 as the meltingpoint in this test method.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.08 on Fats and OilsCurrent edition approved April 1,2009.Published July 2009.Originallyapproved in 1993.Last
15、 previous edition approved in 2003 as D5440 93(2003).DOI:10.1520/D5440-93R09.2Available from American Leather Chemists Assn.,Texas Tech University,P.O.Box 45300,Lubbock,TX 79409.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Precision
16、and Bias7.1 This test method is adopted from the procedure of theAmerican Leather ChemistsAssociation where it has long beenin use,and where it was approved for publication before theinclusion of precision and bias statements was mandated.Theoriginal interlaboratory test data is no longer available.Theuser is cautioned to verify by the use of reference materials,ifavailable,that the precision and bias(or reproducibility)of thistest method is adequate for the contemplated use.8.Keywords8.1 fats a