FULLY AUTOMATED PRECOLUMN DERIVATIZATION, ONLINE DIALYSIS AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF AMINO-ACIDS IN FOOD, BEVERAGES AND FEEDSTUFF

A reliable, high throughput method is described for the routine analys is of amino acids in food, beverages and feedstuff: A fully automated sample processor performs precolumn derivatization of both primary and secondary amino acids with o-phthalaldehyde-3-mercaptopropionic acid and 9-fluorenylmethyl chloroformate (FMOC), respectively. Following di lution and derivatization, an on-line dialysis step is performed to re move macromolecular, microparticulate and insoluble interferents resul ting from complex matrices and the FMOC derivatization. The optimizati on strategies for sample preparation and HPLC are discussed in this wo rk. Twenty-five amino acids (including cystine) present in food produc ts are separated in 24 min using a simple one-step binary gradient, wi th an excellent resolution and outstanding reproducibility. Analytical data are provided both for standard solutions and real samples. (C) 1 998 Elsevier Science B.V.