Flow-Injection-Electrochemical Reduction-Chemiluminescence Determination of Uranium

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 trivalent state by passing through a self-made constant potential flow-electrolytic cell 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%.