Optimizing the separation of major anion and cation groups in water sample for the simultaneous analysis of the most relevant ions by using portable automated dual channel capillary

Abstract

The concurrent separation of major inorganic cations and anions in water sample has been optimized for simultaneous analysis of two ion groups using a home build portable automated dual channel capillary electrophoresis system. The background electrolyte (BGE) solution containing 12mM histidine and 2mM 18-crown-6 adjusted to pH 3.8 with acetic acid has been found for the sufficient separation of cations (NH₄ ⁺, K⁺, Na⁺, Ca₂⁺, Mg₂⁺). Other working conditions of the system have been optimized as follows: separation voltage: -15 kV, valve position: VP 18, time for sample transferring: 1 s, time for sample injection: 2 s. The proper separation of inorganic anions including Cl- , SO4 2-, NO3 - and NO2 - has been offered by using the BGE solution of 12mM histidine adjusted to pH 4.0 with lactic acid, separation voltage at +15 kV, valve position at VP 14 and the same values of time for sample transferring and time for sample injection as for cation separation.