Disposable creatinine sensor based on thick-film hydrogen peroxide electrode system

A disposable creatinine sensor has been developed using a thick-film carbon electrode for hydrogen peroxide. Carbon paste containing 10% Pt powder was metal mask printed on a plastic plate, and irradiated by UV Light under pu re oxygen atmosphere for activation of thick-film electrodes. Thin layer of three different enzymes involving creatininase, creatinase, and sarcosine oxidase was fabricated beside the printed electrode to form a creatinine se nsor. A drop of a test solution automatically runs through a microchannel r eaching the enzyme layer and then the enzymes quickly become solubilized an d disperse throughout the volume of the microchannel. The detection of hydr ogen peroxide at 500 mV vs. Ag/AgCl serves as the analytical signal. The se nsor shows a linear response range for creatinine between 0.2 and 2 mM in a pH 7.5 buffered solution with 0.1 M phosphate and 0.1 M KCl. The oxygen pl asma treatment was found effective on improving the voltammetric behavior o f the thick-film electrodes. (C) 1999 Elsevier Science B.V. All rights rese rved.