Electrochemical Sensing of Uric Acid Using Glassy Carbon Modified with Multiwall Carbon Nanotubes Dispersed in Polyethylenimine

Abstract

This work reports the advantages of using glassy carbon electrodes modified with multiwall carbon nanotubes (MWCNT) dispersed in polyethylenimine (PEI). The presence of MWCNTs wrapped by PEI largely facilitated the strong adsorption of uric acid (UA) and allowed its highly sensitive and selective quantification even in the presence of high excess of ascorbic acid. The selected conditions for the electrochemical sensing were 5 s accumulation at 0.300 V under stirring and quantification in a 0.050 M phosphate buffer solution pH 7.40 by differential pulse voltammetry adsorptive-stripping after medium exchange. The platform allowed the successful application in the quantification of UA in urine.