Determination of pantothenic acid in food by capillary isotachophoresis

Pantothenic acid (vitamin B5) has been quantified in non-fortified and fortified milk-based samples and fortified cornflakes samples by column-coupling capillary isotachophoresis. The leading electrolyte was 10 mmol/l hydrochloric acid including 0.1% polyvinylpyrrolidone adjusted with histidine to pH 6.0. The terminating electrolyte was 5 mmol/l 4-morpholineethanesulfonic acid adjusted with Tris(hydroxymethyl)aminomethane to pH 6.2. The driving current was 350 μA in the preseparation capillary. The driving current was initially 50 μA in the analytical capillary. During detection, the current was reduced to 40 μA. Linearity was observed from 0.50 to 12.0 mg/l with a coefficient of determination (r2) of 0.999. The limit of quantification was calculated to be 1.6 mg/kg. Sample preparation consisted of deproteination with acetic acid followed by centrifugation and filtration. The minimal sample pretreatment and relatively low running costs make isotachophoresis a good alternative to existing methods.