Simultaneous Determination of Chrominum(Ⅵ) and Chrominum(Ⅲ) in Water Sample Using Flow injection On-line Preconcentration and Separation With Flame Absorption Spectrometric Detection
Kong Qingan; Wu Qifan; Guo Xuanhua (Department of Applied Chemistry, South China University of Technology, Guangzhou 510641)
A direct, rapid and sensitive method for the determination of chrominum(Ⅵ ) and chrominum (Ⅲ ) in water samples by flame absorption spectrometry using on-line preconcen ration and separation on a microcolumn packed with anion resin and active alumina (basic form) was developed. Cr(Ⅵ ) and Cr(Ⅲ) could be adsorbed sirnultaneously by the microcol umn, and were eluted directly to the nebulizer by 1 mol/L NH4NO3 and HNO3. The concen tration enhancement of Cr(Ⅵ) and Cr(Ⅲ ) was 11 and 20 time for 25 s sample loading. Ana lytic frequency was 50. samples/h, and recovery of 90% ~ 105% was obtained from mature water. Detection limit (3s ) was 1. 5 and 0. 7μg/L with relative standard deviations (50 μg/L) of 1. 9% and 2. 6% for Cr(Ⅵ ) and Cr(Ⅲ ), respectively.