Analysis of fluorescent vitamins riboflavin and pyiridoxine in beverages with added vitamins

A simple, rapid and inexpensive method has been developed for the determina tion of vitamins riboflavin (B-2) and pyridoxine (B-6) in beverages with ad ded vitamins, and validated by checking the precision from those samples, a nd calibration and detection levels from proper standards. The method involves direct injection of the beverage into an HPLC. B-2 vita min is also analysed by second derivative, synchronous spectrofluorimetry T he precision of the method obtained with samples is satisfactory (RSD < 2.5 %). Detection and quantification limits obtained with standards were 0.02 a nd 0.06 mg L-1 for B-2, and 0.12 and 0.36 for B-6, respectively, which indi cates that these vitamines can be monitored by this method in all kind of v itaminised beverages.