Dynamic double coating,electrophoretic method with indirect detection for the simultaneous quantification of mono‐ and divalent cations in various water samples

An indirect UV detection method based on CE was developed and validated to determinate 12 metal cations, including alkali, alkaline earth, transition metal, and ammonium. In this paper, a new electrolyte system (pH 4.22) contained 20 mM benzimidazole (as co‐ion), 75 mM acetic acid (as a counter‐ion) as well as 0.6 mM 18‐crown‐6 ether was applied. The metal ions were completely separated within 8 min under hydrodynamic mode injection with a running voltage of 20 kV at 25 ± 0.1°C. Additional use of the dynamic double coating method enabled to get an excellent repeatability of migration times and quantitative parameters for all analytes. The repeatability of migration times for analytes were less than 0.9% and peak areas and peak heights ranged from 3.7 to 7.2 and 3.9 to 7.7%, respectively (n = 6). The proposed technique proved to be definitely faster and less expensive in comparison to currently employed methods. In this work, we discuss also the linear range, method detection limits as well as precision and accuracy. The applicability of the elaborated method was authenticated by the quantification of metal ions in commercially available mineral water, tap water, and selected medical injection samples.