Niacin determination in legumes by capillary electrophoresis (CE). Comparison with high performance liquid chromatography (HPLC)

Available and total niacin content in lentils and faba beans have been analyzed by capillary electrophoresis (CE), and the results compared with those obtained by high performance liquid chromatography (HPLC). Acidic and enzymatic hydrolysis have been carried out for available niacin determination, and an alkaline extraction performed for total niacin. The extracts were subsequently purified using a strong anion exchanger resin. Precise conditions for purification had to be worked out for each one of the two analytical methods (HPLC and CE). The HPLC analysis for available and total niacin was carried out in an ion-pair reverse phase column with UV detection at 261 nm, For the CE separation, the following conditions were employed: a 20 mM sodium tetraborate; 15 mM sodium dodecyl sulfate and 20% isopropyl alcohol solution as separation buffer; 30 kV and 25 or 30 degrees C. Separation was carried out in a 70 cm effective length x 75 mu m i.d. fused-silica capillary using on-column UV detection at 254 nm, The results obtained by CE for lentils and faba beans were similar to those obtained by HPLC.