An international collaborative study of a gas chromatographic (GC) method for the determination of trans unsaturation in margarine was conducted in 1980. Thirteen collaborators analyzed a set of 2 of 3 known mixtures of methyl esters and 4 margarine methyl ester samples. Two of the margarine methyl ester samples were blind duplicates. The experimental data were subjected to statistical analysis to determine within- and between-laboratory variation. The statistical data were in excellent agreement with data from a collaborative study of the AOACIUPAC GC method for the determination of methyl esters of fatty acids. Coefficients of variation (CVs) for components in the range of 4-40% were comparable (CV 2-6% for soybean oil methyl esters (AOAC-IUPAC study) as well as for margarine methyl esters (this study)). Good recoveries of total trans acids were obtained and betweenlaboratory as well as within-laboratory CVs were consistently better for the determination of total trans acids by GC vs infrared analysis. The GC method for determining trans unsaturation in margarine has been adopted official first action.

The analysis of silicate and carbonate builders in detergents is time consuming by standard gravimetric procedures (1,2). By modifying established Technicon AutoAnalyzer methods, rapid and simple methods of analyzing these detergent builders have been achieved. Standard AutoAnalyzer modules, arranged for colorimetric analysis, are used, and 10–15 samples per hour can be handled. In the silicate analysis, an aqueous solution of the sample is reacted with ammonium molybdate in an acid medium to form silicomolybdic acid. This acid is partially reduced by ascrobic acid forming the pentavalent molybdenum blue complex. The carbonate method is based upon the evolution of carbon dioxide gas, which is reacted with a buffered phenolpthalein solution. The color intensity of the system is inversely proportional to the carbon dioxide concentration. When a blend of carbonate and bicarbonate is present in the sample, analysis before and after heating is required.

Gas‐liquid chromatography (GLC) of ethylene oxide adducts of fatty alcohols is carried out after conversion of the alcohols to aetate esters. This conversion permits detection of higher mol wt compounds. Separate peaks for adducts with up to 13 units of ethylene oxide are obtained for a product derived from dodecyl alcohol. The procedure is used to follow the course of a molecular distillation of an adduct prepared from hexadecyl alcohol and an example is also shown for an adduct derived from a mixture of dodecyl and tetradecyl alcohols.

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AND SUMMARYA gas chromatographic method is described for the analysis of tetradecane-l,4-sultone (C14 delta sultone) and the combination of 2-chlorotetradecane-1,3-sultone(C14 2-chloro gamma sultone), and 1tetradecene-l,3-sultone (C14 unsaturated gamma sultone) in neutral oils isolated from olefin sulfonate. Samples of the neutral oil are diluted in hexane and injected directly into the gas chromatograph. Quantitative data are obtained by comparison to known amounts of the respective sultones. Through the use of silica gel column chromatography followed by gas chromatography of collected fractions, separation and individual quantitation of the 2-chlorotetradecane-l,3 sultone and 1-tetradecene-l,3-sultone can be obtained. Routine use for control purposes has shown the method to be reliable and interlaboratory agreement of data has been good.