New Developments in Capillary Electrophoresis. Application of Capillary Electrophoresis to Quantitative Analysis and Characterization. Separation of biotin and its relatives by capillary electrophoresis.

Abstract

The migration behavior of biotin and biotin relatives was investigated by capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC). By CZE, biotin, lipoic acid and HABA were migrated as negatively charged species after the electroosmotic flow (EOF), and were separated adequately in the pH range of 7.59.0. However, biocytin, biotin hydrazide and iminobiotin could not be completely separated, because these compounds are electrically, neutral in the buffer solution, and were eluted at a similar velocity as the EOF. The condition of CZE at lower pH required a longer time for the elution of every peaks, and brought about a broadening of the peaks. The migration behavior of biotin relatives was also investigated by MEKC using sodium dodecyl sulfate (SDS). The migrating velocities of biocytin, biotin hydrazide and iminobiotin, which are electrically neutral, were controlled by an interaction with the micelle of SDS. From the relationship between the capacity factors and the SDS concentration, the distribution coefficients for these compounds were evaluated. At an SDS concentration of 0.175 M, a complete separation of six biotin relatives was achieved. The separation of biotin and biotinsulfone was also investigated by CZE and MEKC.