Studings on Polarographic Adsorptive Wave of the System of the Rare Earth(III)-Copper(II)-m-TrifIuomethyl Chlorophosphonazo

摘要

A new heteronuclear complex, rare earth (III)-copper (II)-m-trifluomethyl chlorophosphonazo (CPA-mCF_3) system for determining trace rare earth ions is presented. In a medium of 0. 02mol/ L NH_4Cl, 1. 0×10~(-3) mol/L Cu(II), 1. 0×10~(-5)mol/L CPA-mCF_3, a very sensitive poiarographic adsorptive wave is observed by using a single sweep oscillopolarograph at about - 0. 83V (vs. Ag/AgCl). The linear relationship between the peak current and the concentration of rare earth exists from 6. 0 × 10~(-9) to 1. 0× 10~(-6)mol/L. The detection limit of rare earth is down to 2. 0× 10~(-9) mol/L for Tm~(3+). This method has been applied to determine trace RE in several samples of Chinese tea. The results are satisfactory. The composition of the complex is detected as RE (III) : Cu(II): CPA-mCF_3= 1: 1:2.