Simultaneous determination of thiamine and its phosphate esters by a liquid chromatographic method based on post-column photolysis and chemiluminescence detection

A sensitive method for the post-column detection of thiamine (T) and its phosphate esters is described. The procedure is based on the on-line photolysis of the analytes into photoproducts which have a strong enhancing effect on the CL permanganate–luminol reaction. The complete separation of the thiamines was obtained on a RP-amide C16 column in isocratic elution with an analysis time of less than 7 min. Under the optimum conditions, analytical curves, based on standard solutions, were linear over the range 10–1000 nM for thiamine and 100–2000 nM for its mono- and di-phosphate esters. Intra- and inter-day precision values of less than 1.14% relative standard deviation (RSD) (n = 10) and 1.86% RSD (n = 15), respectively, were obtained. The method was successfully applied to the determination of the thiamines in pharmaceutical preparations and baby foods.