The application of capillary electrophoresis to the determination of total niacin in concentrated yeast spreads

A rapid capillary electrophoretic method for the determination of total niacin in concentrated yeast spreads has been developed. Nicotinic acid is liberated from the food matrix by autoclaving the sample in aqueous calcium hydroxide. The sample solution is then passed through an activated C18 Sep-Pak cartridge followed by cation exchange chromatography using commercially available SCX columns. The nicotinic acid then is determined by capillary electrophoresis using a 75 cm × 75 μm uncoated fused silica capillary column with a buffer comprising of a 1:1 mixture of 0.02 M sodium tetraborate and 0.02 M disodium hydrogen orthophosphate pH 9.2. The levels of nicotinic acid determined by capillary electrophoresis were in good agreement with those obtained by the traditional AOAC colorimetric procedure (e.g. CE 126 mg/100 g, AOAC 129 mg/100 g).