Rapid Determination of Seven Water-Soluble Vitamins in Starch-Fortified Foods

A method using high performance liquid chromatography with diode array detector and fluorescence detector (HPLC-DAD-FLD) was established to simultaneously analyze seven water-soluble vitamins in starch-fortified foods. The sample was hydrolyzed by amylase at 60 ℃ for 45 min and ultrasonically extracted after pH adjustment. Chromatographic separation was carried out by gradient elution using 5 mmol/L sodium dodecyl sulfate solution containing 0.1% phosphoric acid adjusted to pH 3.0 with triethylamine as mobile phase A and acetonitrile as mobile B. Vitamin B₁, niacin and nicotinamide were detected at maximum UV absorption wavelengths. Good linearity was observed for all analytes with correlation coefficients (r²) of 0.9996–0.9999. The recoveries for spiked samples were 90.5%–102.5%, the limits of detection (LODs) were 0.01-0.08 mg/100 g, and the limits of quantitation were 0.025–0.26 mg/100 g. The developed method is rapid, efficient and suitable for the simultaneous determination of the seven vitamins in bulk starch-fortified foods.