Use of BPX-70 60-m GC columns for screening the fatty acid composition of industrial cookies

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Abstract

The fatty acid (FA) composition of food is requested for labelling purposes and food composition tables. Suitable analytical methods for labelling purposes must be able to efficiently identify and accurately quantify FA as swiftly and cheaply as possible. This study evaluated a middle-length highly polar column, the BPX-70 60-m column, to balance analysis efficiency and duration. The use of a 60-m column led to the loss of data on minor FA but a gain in analysis time. The column was evaluated by analysing the FA composition of ten cookies made with different kinds of fats, including milk fat, and pure and/or partially hydrogenated vegetable oils. The FA elution order in this GC phase has been poorly documented in the literature compared to equivalent highly polar CPSil-88 and SP-2460 GC phases. Co-elutions and overlaps on the BPX-70 column were studied and commented upon. Overall, the BPX-70 60-m column could be used for rapid screening of the FA composition of simple foods. Analysis of the FA composition of a complex matrix, such as a dairy product, and specific analysis of trans-FA required a longer highly polar column, possibly after fractionation by silver-ion liquid chromatography. Compared to other GC phases, the BPX-70 enabled effective isolation of 18:3 isomers although these isomers co-eluted with 20:1 isomers on other highly polar GC phases. However, some CLA isomers co-eluted with other FA on this column, and a specific analysis of these special FA would require another phase and/or different chromatographic conditions.

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