Gas chromatographic triglyceride profiling of milk fat; comparison of packed and short metal capillary columns

Abstract

The quantitative aspects of triglyceride profiling of milk fat by capillary column gas chromatography (GC) were investigated. Fifty samples of pure Austrian milk fat were tested as described in Annex III of the European Community (EC) Commission regulation no. 454/95 by using a packed as well as a short metal capillary column. Capillary GC was equivalent to the packed column in terms of analytical precision (relative standard deviation of repeated injections). All samples tested fulfilled the purity criteria (S-values), irrespective of the chromatographic technique used. Nevertheless, the S-values obtained by capillary GC deviated to some extent from those of the packed column. The differences exceeded the value for reproducibility laid down in Annex III, EC regulation no. 454/95 in 18 of 50 cases. As a consequence, the equivalency of capillary GC for determining the purity of milk fat according to EC regulation no. 454/95 should be re-assessed.