Determination of trace Cd(II) and Zn(II) on a micro-column filled with polyacrylonitrile coupled with flame atomic absorption spectrometry

In this paper,the adsorption properties of Cd2+ and Zn2+ on the micro-column(2.5cm×4 mm i.d) filled with polyacrylonitrile microsphere as the adsorption material synthesized by ourselves were studied by flame atomic absorption spectrometry.The Adsorption conditions f Cd2+ and Zn2+ on the column such as pH,flow rate and time et al were optimized.The results showed that at the room temperature,pH of solution was 5～6,the flow rate and time of loading sample were 6 mL/min,and 10 min and the eluant 3.0 mL/min and 1 min respectively.The as-prepared micro-column had excellent adsorption properties and high adsorption capacities for Cd2+ and Zn2+ which reached 47.6 and 39.3 mg/g respectively.0.50 mol/L chloride acid showed the best desorption property and the recovery reached 99%.The detection limits(3σ,n=10) were 1.06 and 0.855 μg/L with the relative standard deviations(RSDs) of 2.6 and 1.8% respectively.This method was applied to the determination of trace cadmium and zinc from environmental samples,the recoveries were in the range of 94.0%～102.6% and 94.6%～100.4% respectively.