Determination of cadmium by ethanol-ammonium sulfate two-phase extraction combined with flame atomic absorption spectrometry

The ethanol-ammonium sulfate two-phase extraction system for cadmium was developed.The main influencing factors for the extraction of cadmium by ethanol-ammonium sulfate two-phase system were investigated with flame atomic absorption spectrometry(FAAS).Moreover,the extraction mechanism was preliminarily discussed by Fourier transform infrared spectrometry(FT-IR).The results showed that Cd2+ could form stable purple complex with I-and crystal violet in ethanol-ammonium sulfate two-phase system at pH 5.0-6.0.Under the optimal extraction conditions,cadmium could be well separated from other common metal ions.The extraction rate was up to 100 %.The linear range of calibration curve was 0-0.50 μg/mL,with the linear correlation coefficient of 0.999 3 and the detection limit of 0.012 μg/mL.The proposed method was applied to the determination of cadmium in environmental water samples.The relative standard deviations(RSD) were 2.8 %-3.6 %,and the recoveries were higher than 95%.