On line supported liquid membrane enrichmentflow 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 NH4Ac 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(Ⅱ) 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 cadmiun(Ⅱ) in standard water samples and the determination results are agreement with the certified values.