With the presence of KI,Cd(II)can react with I-to form metal complex anions CdI3-and CdI42-at pH 1.0～6.0,which can be well adsorbed on Triphenylmethane loaded with by tetradecyl benzyl dimethyl ammonium chloride.Under optimized conditions Cd(II) can be completely separated from Zn(II),Fe(III),Co(II),Ni(II),Mn(II),Al(III) and hardly affected by SO42-,NO3-,Br-,Cl-,I-.The method was successfully applied to the concentration and determination of trace cadmium in environmental aqueous samples.The preconcentration factor can reach 100 ～200 times.The recovery is above 98%.
