HPLC DETERMINATION OF VITAMIN-B6 IN FOODS AFTER PRECOLUMN DERIVATIZATION OF FREE AND PHOSPHORYLATED VITAMERS INTO PYRIDOXOL

A method to determine the content of vitamin B-6 in foods by ion pair high performance liquid chromatography is proposed and includes pre-co lumn transformation of phosphorylated and free vitamers into pyridoxol followed by fluorescence detection. Dephosphorylation of vitamers is first achieved by enzymatic hydrolysis (acid phosphatase). By reaction with glyoxylic acid in presence of Fe2+ as catalyst, pyridoxamine is transformed into pyridoxal, which is then reduced to pyridoxol by the action of sodium borohydride in alkaline medium. The proposed method h as a good recovery rate (90-95%), a satisfactory repeatability (coeffi cient of variation less than 8%) and a very low detection limit (0.02 mug g-1).