Electrochemical Characterization of Iron (III) Doped Zeolite-Graphite Composite Modified Glassy Carbon Electrode and Its Application for AdsASSWV Determination of Uric Acid in Human Urine.

Meareg Amare

doi:10.1155/2019/6428072

Abstract

Iron (III) doped zeolite/graphite composite modified glassy carbon electrode was prepared for determination of uric acid in human urine samples. Electrochemical impedance spectroscopic and cyclic voltammetric results confirmed surface modification of the surface of glassy carbon electrodes. Appearance of oxidative peak current with an over threefold enhancement at significantly reduced overpotential for uric acid at the composite modified electrode relative to the unmodified and even graphite modified electrode confirmed the electrocatalytic property of the composite towards electrochemical oxidation of uric acid. Under optimized method and solution parameters, linear dependence of peak current on uric acid concentration in a wide range of 1-120 μM, low detection limit value (0.06 μM), replicate results with low RSD, and excellent recovery results (96.61-103.45%) validated the developed adsorptive anodic stripping square wave voltammetric (AdsASSWV) method for determination of uric acid even in aqueous human urine samples. Finally, the developed composite modified electrode was used for determination of uric acid content in human urine samples collected from three young male volunteers. While the uric acid level in the urine samples from two of the studied volunteers was within the normal range, of the third was under the normal range.

Highlights

Uric acid (2,6,8-trioxypurine) (Scheme 1) is a compound endogenously produced by animals as a purine metabolite
Oxidation at a reduced overpotential compared to at bare glassy carbon electrode indicating the catalytic property of the modifier towards oxidation of uric acid (UA)
The method using composite modified electrode was validated for its applicability for determination of UA in human urine samples

Summary

Introduction

Uric acid (2,6,8-trioxypurine) (Scheme 1) is a compound endogenously produced by animals as a purine metabolite. It is the end product of purine metabolism in humans due to the loss of uricase activity making humans have higher uric acid (UA) level than other mammals [1, 2]. UA is produced by the liver leading to normal uric acid concentration of 3.4–7.2 for men and 2.4–6.1 mg/dL of plasma for women which is excreted by the kidneys (6575%) and intestines (25-35%) [1, 2]. Development of a simple, rapid, and sensitive method for continual monitoring of its level in human body fluids including urine is vital. A range of techniques including chromatography [7, 8], electrophoresis [9, 10], potentiometry [11], spectroscopy [12], and amperometry [13] have been reported for determination of UA in different samples

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Conclusion