DETERMINATION OF ALKALI AND ALKALINE-EARTH METALS IN REAL SAMPLES BY CAPILLARY ION ANALYSIS

Imidazole-H2SO4 background electrolyte was used to perform capillary i on analysis with indirect UV detection. Baseline separation of K, Na, Ca, Mg and Mn was achieved and the resolution could be enhanced by dec reasing the pH of the electrolyte buffer. The electromigration dispers ion for Na was smaller in the imidazole-H2SO4 buffer than in the backg round electrolyte containing UVCat1 (a UV-absorbing amine) and 2-hydro xyisobutyric acid. This therefore resulted in less Na peak broadening. As a consequence, large amounts of Na could be separated efficiently without interference with the other analyte cations. The method was va lidated for the quantitative analysis of pharmaceutical electrolyte so lutions and beverages, and compared with flame atomic spectrometry for evaluation.