Microelectrophoretic and chromatofocusing techniques for the quantitative separation and identification of imidazole derivatives

Abstract

The separation of eleven naturally occuring imidazole compounds by low-voltage electrophoresis on cellulose acetate using a wide-range buffer covering the pH range 3.5–11.5 is described. The recoveries of urocanic acid, histamine and histidine varied from 80 to 100% for concentrations of 1–7 μg. The results are reproducible and the technique could be useful for the rapid identification and determination of histidine metabolises. A mixture of nine imidazole derivatives was resolved on Dowex 50W-X8 (200–400 mesh) using a linear pH gradinent of the wide-range buffer. The elution pH values of the different imidazole compounds varied from +0.6 to – 0.4 pH unit above or below their isoelectric pH values. The recoveries of the standards ranged from 86 to 98%. This technique was applied successfully to the separation of histidine metabolites in A. aerogenes culture medium.