On line supported liquid membrane enrichment-flow injection spectrophotometric determination of trace cadmium(II) in water

An on line supported liquid membrane enrichment-flow injection spectrophotometry for determination of trace cadmium(II) in water has been developed, and a flow carrier, hexadecylamine dissolved in kerosene is used in the supported liquid membrane extraction system. Experiment conditions were optimized. The results obtained were as follows: the concentration of HCl is 0.04 mol/L, the concentration of NH₄ Ac as a reextraction solution is 0.02 mol/L, the concentration of hexadecylamine is 0.02 mol/L, the aperture of PTFE membrane is 0.2 μm, the enrichment time is 20 min. The detection limit for cadmium QD is 0.05 μg/L, the linear range of the determination is 0.10-40 μg/L, and the relative standard deviation (RSD) is 2.38% for 10 μg/L cadmium(II) (n = 5). The method can be applied to the determination of trace cadmium(II) in standard water samples and the determination results are agreement with the certified values.