Multivitamin methods liquid chromatography determination

The first liquid chromatography-mass spectrometry (LC-MS) method was developed by Stokes and Webb (1999). Here, folate was separated using reversed-phase chromatography, detected in a single ion monitoring (SIM) mode and quantified using external standards [25]. These authors successfully identified and determined folic acid, tetrahydrofolate, 5-methyltetrahydrofolate, and formyltetrahydrofolate in multivitamins and foods. 

Vidovic, S., Stojanovic, B., Veljkovic, J., and Prazic-Arsic, L., 2008. Simultaneous determination of some water-soluble vitamins and preservatives in multivitamin syrup by validated stability-indicating high-performance liquid chromatography method. Journal of Chromatography A. 1202 155-162. 

High-performance liquid chromatography (HPLC) methods have been comprehensively applied to the determination of biotin in pharmaceutical multivitamin preparations. Some of them have also been used to analyse more complicated matrices of samples, e.g. food material (Livaniou et al. 2000). Biotin detection by HPLC can be achieved with (either pre- or post-column) or without sample derivatization (Livaniou et al. 2000). 

Pantothenic acid, its salts, and panthenol as such are not volatile enough for direct gas-liquid chromatography (GLC). However, it is possible to use this chromatographic technique after derivatization of the polar hydroxyl and carboxyl groups of the vitamin (23,38,72,73,75-79). The majority of the developed methods are, however, applicable only to relatively pure and simple samples such as multivitamin preparations, and certain biological samples, such as urine (75-77). Only a few methods are suitable for the determination of the vitamin in complex matrices such as foods. An overview of methods was given by Velisek et al. (5). 

Folic acid can be determined in methods designed for multivitamin analysis either from multivitamin preparations (90-93) or from fortified samples such as infant milk (94). In these methods trichloroacetic acid extraction of liquid and powdered infant milk followed by ion pair chromatography with reversed-phase Cig column was applied. Satisfactory separation was achieved with octanesulfonic acid (5 mM) with triethylamine (0.5%) in methanol-water (15 85 v v) at pH 3.6 (Fig. 6). UV detection and wavelength switching were used for six vitamins giving sensitivity of 1 ng folic acid per injection (282 nm for folic acid). Total run time of this isogratic separation was 55 min. This approach has not been reported for nonfortified samples. 

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