INTERLABORATORY STUDIES OF HPLC PROCEDURES FOR THE ANALYSIS OF CAROTENOIDS IN FOODS

This paper describes the use of a potential reference material in inte rlaboratory studies for the analysis of carotenoids in a mixed vegetab le material. Seventeen European laboratories have carried out collabor ative studies to assess the accuracy of HPLC procedures for the measur ement of lutein, zeaxanthin, lycopene, alpha-carotene and beta-caroten e in a vegetable mix. The studies investigated possible problem areas including chromatographic systems, standardization of carotenoid stock solutions, extraction procedures and data handling. The results sugge sted that the effect of the chromatographic system is probably not a m ajor variable, although some systems achieved a more discrete separati on of carotenoid isomers than others. In the more experienced laborato ries, variation in the standardization of the carotenoid solution was not thought to be a significant problem. However, there were greater v ariations for lycopene calibration and measurement. Preliminary conclu sions from these studies suggested that the preparation of the caroten oid extract may account for about 13% of the overall variance of aroun d 23%. Copyright (C) 1996 Elsevier Science Ltd