A paired ion liquid chromatographic method for thiamine determination in selected foods

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