Development of an Electrochemical Sensing Device for Detection of Uric Acid in Dialysate Effluent

Abstract

A significant problem encountered frequently in the detection of uric acid (UA) is the interference of ascorbic acid (AA), which coexists in biological fluids and can be oxidized at a potential close to that of UA on various types of electrodes. In this study, we developed a portable computer-controlled potentiostat for non-enzymatic electrochemical determination of uric acid (UA) in effluent dialysate at glassy carbon electrodes. The device can perform multi-pulse voltammetry (MPV) that involves stepping the potential to different levels in short durations, followed by a rest. The differential current is then measured between two consecutive pulses. By optimization of waveform parameters, MPV can suppress the oxidative current of AA and can provide better resolution in the analysis. Selective detection of UA was achieved even if 1.5 mg dL⁻¹ (85 μmol L⁻¹) AA co-existed in the dialysate effluent. The proposed method exhibits excellent selectivity and stability for the quantitative determination of UA in effluent dialysate, and the results are in good agreement with those obtained with the conventional enzyme-based spectroscopic method in the concentration range of 0 ~ 2.0 mg dL⁻¹, suggesting the proposed method a great promise for enabling real-time determination of UA in dialysate effluent.