two methods for determining erucic acid in edible fats and oils results from a collaborative study on a rapid opentubular capillary glc method and comparison with an isolation tlc procedure the results of an international collaborative study for the determination of 5 erucic acid in four samples of edible fats and oils with differing levels of 221 isomers other than erucic acid based on the use of wallcoated silar5cp opentubular gasliquid chromatography are examined the same samples had been analyzed in a separate collaborative study by an alternative and more complex method based on argentation thinlayer chromatography both methods rejected about the same proportion of participating laboratories and a few individual results from otherwise acceptable laboratories the means and repeatabilities of the two methods were similar but the gasliquid chromatographic method showed better reproducibility