Determination of Trace Cd(II)in Traditional Chinese Medicine by Flame Atomic Absorption Spectrometry after Separation and Preconcentration with Ions Imprinting of Chitosan/Attapulgite

A method for the determination of trace Cd(Ⅱ)in traditional chinese medicine by FAAS after separation and preconcentration with Cd(Ⅱ)ions imprinted chitosan/attapulgite(IICA)has been established.Under the dynamic adsorption conditions,the optimal pH of the solution,flow rate,elution conditions were obtained for preconcentration of trace Cd(Ⅱ),and the effect of interfering ions was also investigated.It was found that Cd(Ⅱ)could be quantitatively preconcentrated on IICA at pH=4.5.The flow rates of sample solutions and eluting solution with 1.0 mol/L HCl-0.1 mol/L methyl isobutyl ketone alcohol were 0.60mL/min and 0.96mL/min,respectively.The dynamic adsorption capacity of Cd(Ⅱ)on IICA was 56.45 mg/g.The linear range for Cd(Ⅱ)was 0.00097～1.28 mg/L,with a correlation coefficient of 0.9994.The detection limit for Cd(Ⅱ)was 0.97μg/L(3σ,n=11).The relative standard deviation was 1.32%(n=6,c=0.08mg/L),and the recovery was in the range of 96.5%～ 106.4%.The method is convenient,highly precise and linear in a wide range and has been applied to the determination of trace amount Cd(Ⅱ)in water samples with satisfactory results.