( Introduction ...)Unique Surface Treatment of Novel TSK-GEL ODS Columns Provide Separation of Aqueous and Fat Soluble Vitamins

Introduction
With the introduction of two new reversed-phase column types, TSKgel ODS-100V and TSKgel ODS-100Z, excellent chromatographic performance and selectivity can be achieved for a wide range of sample types. TSKgel ODS-100Z and TSKgel ODS-100V are based on a spherical, five micron, silica gel with 100 angstrom pores; each material is derivatized with difunctional octadecylmethylsilane, followed by an exhaustive endcapping reaction.TSKgel ODS-100Z contains approximately 20% carbon, while TSKgel ODS-100V has a lower ligand density resulting in about 15% carbon, which in turn leads to stronger retention of polar compounds.

The analysis of water- and lipid-soluble vitamins requires both hydrophilic and hydrophobic retention capabilities of the stationary phase. Also, the composition of the stationary phase must allow for stable retention times in the absence of organic solvents in the mobile phase. As demonstrated, simple and fast analysis methods for the determination water and lipid soluble vitamins are possible on the TSKgel ODS-100V and the TSKgel ODS-100Z columns.

Analysis of Water Soluble Vitamins
A mixture of six water soluble vitamins was analyzed on TSKgel ODS- 100V and TSKgel ODS-100Z under isocratic conditions with 99% water- 1% acetonitrile, acidified with 0.1% TFA to a pH of 2.0. At an optimized temperature of 40C good separation was obtained for all compounds in less than 10 minutes (see Figure 1 ).

Both columns managed to separate all vitamins by baseline. Thiamine, pyridoxal and pyridoxine were better separated on the more polar TSKgel
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