Investigation of a novel Ag(III) chemiluminescence system and its mechanism for determination of uric acid in human urine

A simple and sensitive method based on flow-injection chemiluminescence analysis coupled with luminol-Ag(III) complex was developed for the determination of uric acid (UA) in human urine. The method was based on the chemiluminescence (CL) reaction of luminol with Ag(III) in alkaline solution. UA in the urine can dramatically enhance CL intensities. In optimum conditions, the relative CL intensity had a linear relationship with UA concentration in the range of 1.0 x 10(-8) to 5.0 x 10(-6) mol L-1 with a detection limit of 2.0 x 10(-9) mol L-1 (3 sigma). The relative standard deviation (n = 11) was 0.71% for 1.0 x 10(-7) mol L-1 UA. Possible reaction mechanisms for the CL system were suggested based on the UV absorption spectra, CL spectra, and the free radical trapping experiment performed in this work.