流动注射电化学还原-化学发光法测定铀

Flow-Injection-Electrochemical Reduction-Chemiluminescence Determination of Uranium

采用恒电位电解技术，使不具发光活性的铀（Ⅵ），通过自制的流通式碳电解池后，在-0．70V（vs，Ag／AgCl）电位下在线还原为铀（Ⅲ），铀（Ⅲ）与鲁米诺在碱性条件下产生化学发光，从而建立了铀的流动注射电化学发光分析法。方法的线性范围为1．0×10^-6～1．0×10^-2g·L^-1，检出限2×10^-7g·L^-1，RSD为2．5％（n=13）。该方法用于合成海水中铀的测定，回收率为98．0％～103．3％。

A FIA manifold for the chemiluminescence determination of uranium in seawater was designed, composing the process of online pre-reduction of the chemiluminescently inactive U （Ⅵ） to its tfivalent state by passing through a self-made constant potential flow-electrolytic eell with spectrographically pure, hallow carbon electrode as working electrode at -0. 70 V （vs. Ag/AgCl electrode） and the process of chemiluminescence reaction of U（Ⅲ） with luminol in an alkaline solution. The chemiluminescence was treated with the software IFFM and linearity between values of peak height and concentration of U（Ⅲ ） was kept in the range of 1.0 × 10^-6 -1.0 × 10^-2g· L^-1. Detection limit of the method was 2. 0 × 10^-7g · L^-1 for U（Ⅵ）. Precision of the determination were tested at the concentration level of 1.0 × 10^-4g· L^-1 giving the value of RSD＇s （n=13） of 2. 5%. Recovery test was made on the base of a simulated seawater sample by the standard addition method, and values of recovery were in the range of 98. 0%-103. 3%.