A PAIRED ION LIQUID-CHROMATOGRAPHIC METHOD FOR THIAMINE DETERMINATIONIN SELECTED FOODS

A precise and selective method for determining the content of thiamine in dietetic and baby foods by reverse phase liquid chromatography wit h UV detection is proposed. Enzymatic extracts of food samples were su bjeted to purification and preconcentration with a weak ionic exchange column (CBA) and 0.1 M BaCl2 solution as eluent. Ion-pair chromatogra phy using a C-18 column and a mixture of 5 mM sodium hexanesulphonate as counter-ion, 10(-2) M potassium dihydrogen orthophosphate/phosphori c acid buffer solution, pH 2.8, and 0.1% triethylamine was employed. T he thiamine was detected at 254 nm. This method was used to determine the content of thiamine in baby meals, cereals and dietetic cookies. R ecovery studies showed good results and the relative standard deviatio n (n=10) was 2.9%.