LC Simultaneous Determination of the Free Forms of B Group Vitamins and Vitamin C in Various Fortified Food Products

An LC–UV screening method for simultaneous determination of ascorbic acid (C), and the free forms of thiamine (B1) riboflavin (B2), niacin (B3), pyridoxine (B6) in enriched food products was developed and validated. The chromatographic separation was accomplished within 18 min using a gradient of water with 0.1% formic acid (pH 2.5) and methanol with 0.1% formic acid on a C18 reverse phase column (5 μm, 150 × 3.2 mm) while detection was performed at two wavelengths (266 and 290 nm). Sample preparation was based on an extraction method originally developed for vitamin C. This procedure besides extracting vitamin C was extended to the extraction of the free forms of vitamins B1, B2, B3, B6 and B9. The developed analytical method was successfully applied for the simultaneous determination of the vitamin C content along with the free vitamin B forms of three different enriched food products.