Report of the AOCS Instrumental Techniques Committee, 1972–73

Abstract

The Committee met twice during the year at the 46th Fall Meeting of the Society in Ottawa, Canada, and at the 64th Spring Meeting in New Orleans, La. The Spectroscopy Subcommittee had planned to study, in collaborative investigation, 2 published methods, 1 designed to provide a rapid determination of isolatedtrans isomers without recourse to external standards and the other to increase the sensitivity of these determinations. However, these investigations have been delayed because of lack of interest and inability to establish task groups within various laboratories. The Atomic Absorption Subcommittee completed collaborative testing of a method originating at the Southern Regional Research Center for the direct determination of trace metals in fats and oils by atomic absorption spectroscopy. The method will be submitted to the Uniform Methods Committee with recommendation for inclusion in theAOCS Book of Official and Tentative Methods. This Subcommittee has found that methods to provide increased sensitivity in determining small traces of metals by preconcentration by means of extraction procedures are not entirely satisfactory. Apparently this is because of inability to quantify the extraction preconcentration procedure. It will attempt to develop a more sensitive method, required for the analysis of refined oils, by the use of graphite furnace and carbon rods or carbon tube atomizers. Resignations of the chairman and 2 task group chairmen of the Gas Chromatography Subcommittee necessitated a reorganization of this Subcommittee, delaying plans to establish collaborative evaluation of methods for the determination of: (a) pesticides; (b) sterols; (c) resin acids in fats, oils, and other lipids; (d) the composition of turpentine by means of gas liquid chromatography; and (e) the composition of fatty acids by means of programed gas liquid chromatography. The NMR Spectroscopy Subcommittee conducted several collaborative tests to show that the instrumental method has advantages over the present dilatometric procedure in precision, scope, and time of analysis. The NMR procedure was found satisfactory with either wideline or pulsed-source instrumentation but was dependent upon the method of tempering of the sample prior to analysis. A method specifying a precise tempering procedure in detail will be studied in additional collaborative tests. Satisfactory results will permit development of a specific procedure to be recommended as an offical method of the Society.