Investigation of a Novel Ag(III) Chemiluminescence System and its Mechanism for Determination of Uric Acid in Human Urine

Li Ma,Wei Wang,Weijun Kang,Lingmei Niu,Hongmei Shi

doi:10.5935/0103-5053.20140050

Abstract

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 × 10-8 to 5.0 × 10-6 mol L-1 with a detection limit of 2.0 × 10-9 mol L-1 (3σ). The relative standard deviation (n = 11) was 0.71% for 1.0 × 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.

Highlights

Uric acid (2,6,8-trihydroxypurine, uric acid (UA)) is a relatively water-insoluble end product of purine metabolism in humans and is excreted via urine.[1]
A recent study suggested that low serum/cerebrospinal fluid levels of UA are one of the biomarkers of Parkinson’s disease and that high UA levels could slow the progression of this disease.[4]
Based on the UV absorption spectra, chemiluminescent spectra and the results of the free radical trapping experiment performed in this study, possible reaction mechanisms for the CL system are suggested

Summary

Introduction

Uric acid (2,6,8-trihydroxypurine, UA) is a relatively water-insoluble end product of purine metabolism in humans and is excreted via urine.[1]. CL has better sensitivity, lower detection limits, wide linear ranges, and lower cost. We present a simple, sensitive, and accurate analytical method by using the luminol-Ag(III) complex system for the determination of UA in human urine. Bis(hydrogen periodato)argentate(III) complex anion (Ag(III)) was synthesized according to the procedure described previously.[24] The concentration of Ag(III) stock solution was determined spectrophotometrically at 362 nm by use of the molar absorptivity of ε = 1.26 × 104 L mol‐1 cm‐1. The sample solution was injected into the carrier stream (water) via the six-way injection valve and met with mixed [Ag(HIO6)2]5–/luminol solution in manifold M2. The CL spectra were obtained using an F-7000 fluorescence spectrophotometer (Hitachi, Japan)

Results and Discussion

Method

Conclusions