| Vitamins are essential to human beings and support long-term healthy lifestyle. They exist widely in food, but in small amount. Hence, dietary supplements and fortified food products are more and more popular in the nutritional markets. According to the Infant Formula Act of 1980, the range of each of the nutrients should fall within a specific range or above the required minimum, so there is an increasing interest of accurate measurement of vitamins, particularly the B-group vitamins. However, traditional methods for vitamin B analyses are time-consuming and often in poor accuracy. As a result, rapid and reliable analytical methods for simultaneous determination of water-soluble vitamins in multivitamin and supplemented foods are important, indispensible and needed by food and nutraceutical industries for quality control during production, and for accurate evaluation of data and label clams.;Due to low concentrations of B8 and B9 in nature, there is a critical need for preconcentration to facilitate their isolation and purification from a complex matrix like food. In order to minimize the consumption of solvents, solid phase extraction (SPE) has been introduced for sample preparation. In this study, two types of SPE, i.e., reversed-phase C18 and strong anion-exchange phase, were used for sample clean-up and pre-concentration. The average recoveries for vitamin B3, B5, B7 and B9 were 101.3%, 102.9%, 92.8% and 102.6%, respectively, by using C18 SPE. In contrast, the strong anion-exchange SPE provided the average recoveries of B3, B5, B7 and B9 in 91.5%, 93.0%, 109.1% and 106.7%, respectively.;Furthermore, simultaneous determination of water-soluble vitamins was developed by a HPLC system installed with a ZORBAX Eclipse XDB-C18 (250mm x 4.6mm, 5 &mgr;m particle size, Aglient Technologies, Inc., Loveland, CO, USA) with a guard column (12.5mm x 4.6mm, 5 &mgr;m particle size), and compared by three detectors, including DAD, ELSD and MS. The B-complex supplement, multivitamin/multimineral tablets and powder and vitamin drink were tested to verify HPLC method. According to the results, LC-MS is the best to do the simultaneous determination of the B-group vitamins in lights of its analytical accuracy, precision, sensitivity and versatility. |
