【摘要】 本文报道了在醋酸—醋酸钠缓冲溶液中,稀土离子与2.6—二羧酸吡啶体系的极谱行为及其电极过程机理的研究。更多还原

【Abstract】 Near -0.94V (S. C. E.) acid dipicolinate ion (HL-) has a D. C. polarographic wave in HAc-NaAc buffer solution. Rare earth ions decrease the height of this wave. Under optimum conditions, such as 0.2M HAc-NaAc, CDPA = 2 × 10-5M, at pH 3.5-4.5, the decrease of wave height with the concentration of terbium (Ⅲ) is linear in the range from 5×10-7M to 5 × 10-6M. Heavy rare earth ions are more sensitive than light rare earth ions. Gadolinium is the most sensitive one among them.In the analytical conditions, CDPA>CRE, the mechanism of the electrode processes may be shown as follows:HL-diffuses from bulk solution to the surface of electrode, which then is reduced to the tetrahydro-compound. At the same time, in reaction layer, HL-is produced by the preceding reactionwhich also can be reduced.When the value of rate constant k is large, then the height of wave decrease slowly.更多还原