IC Determination of 5 Inorganic Cations in Water Sample of Water Project

A method for rapid determination of 5 cations in water sample of water project, including Na⁺, NH₄⁺, Mg²⁺, Ca²⁺ and K⁺, by the novel and high throughput ion chromatography (IC) was proposed. Five cations were separated well in 18 min by TSKgel SuperIC-CR cation exchange column under gel suppressed conductivity detection, and a mixture of 2.2 mmol·L^-1 methanesulfonic acid solution and 1.00 mmol·L^-1 18-crown-6 solution was used as eluent at a flow rate of 0.7 mL·min^-1, with column temperature of 40 ℃. Linear relationships between values of peak area and mass concentration of the 5 cations were kept in definite ranges. The detection limits (3S/N) of Na⁺, NH₄⁺, Mg²⁺, Ca²⁺ and K⁺ were 7.1, 6.3, 9.5, 10.0, 8.3 μg·L^-1, respectively. Values of recovery of the 5 cations in water samples were in the range of 95.3%-104%, with RSDs (n=5) ranged from 0.26% to 4.0%.