Electrophoretic Behaviour of Biotin and Biocytin in Capillary Electrophoresis. Determination of Biotin in Pharmaceutical Formulations

Summary

The migration behaviour of biotin and biocytin was investigated by capillary zone electrophoresis (CZE). The results indicate that with a 50 mM borate buffer at pH 9.0 the separation is excellent. The CZE method can be applied to the determination of biotin in multi-vitamin preparations. However, for samples with a low biotin content, a micellar electrokinetic chromatography (MEKC) approach was developed in order to avoid the overlapping of the small peak of biotin with the large peaks of other vitamins. As electrophoretic electrolyte the MEKC method uses a solution containing 20 mM phosphate buffer (pH 7.5), 75 mM sodium dodecylsulphate and 30% (v/v) methanol. The performance of the method was tested in the analysis of two pharmaceutical preparations.