Simultaneous Analysis of Water-Soluble Vitamins in Vitamin-Enriched Beverages and Multivitamin Dietary Supplements by UHPLC-MS/MS

Vitamins are nutrients essential to human health, and are present in almost all types of foods. In addition to food sources, vitamin supplements are often consumed to ensure adequate vitamin intake, as a customary diet does not always provide sufficient vitamins due to bias and/ or limitation in the choice of foods, or malfunctions in digestion and ingestion. Vitamin supplements are available in various forms such as singleor multivitamin tablets, formula, and vitamin-enriched beverages (VEB). Certain foods are commercially fortified with vitamins and/or other nutritional essentials such as minerals. Based on their solubility, vitamins are divided into two categories: watersoluble vitamins (WSV) and fat-soluble vitamins (FSV). WSVs include vitamin C (ascorbic acid), B1 (thiamine), B2 (riboflavin), B3 (niacin, niacinamide), B5 (pentothenic acid), B6 (pyrodoxine), B7 (biotin), B9 (folic acid), and B12 (cyanocobalamine). Accurate quantitative measurements for vitamins are required to ensure product quality and regulatory compliance as well as to monitor vitamin intake. Established methods for vitamin analysis include microbiological methods, which are typically designed for single vitamin analysis and are time consuming,1,2 and chromatographic methods, including gas chromatography,3,4 capillary electrophoresis,5,6 and liquid chromatography (LC) with various methods of detection.7–16 LC methods are generally used for simultaneous determination of multiple vitamins of interests and for establishing vitamin profiles in a variety of matrices with various modes of detection.7–10, 13–16 Here we present a highthroughput method for simultaneous determination for the above mentioned ten WSVs using ultrahigh-performance LC and tandem mass spectrometry (UHPLC-MS/MS). Chromatography was optimized for the total resolution of all target analytes on a Thermo Scientific Acclaim C30 reversed-phase (RP) column. An MS/MS instrument was operated in selected reaction monitoring (SRM) mode for the best selectivity and sensitivity, and an isotope labeled internal standard (IStd) was used for accurate quantitation. Randomly selected VEBs and multivitamin supplement tablets (MVSTs) were assayed by this method for selected vitamins. Much higher values were observed for most vitamins in VEBs than indicated on product labeling. Results also showed close agreement between observed and label values for MVSTs.