Abstract
A disposable screen-printed carbon electrode (SPCE) modified with chemically reduced graphene oxide (rGO) (rGO-SPCE) is described. The rGO-SPCE was characterized by UV-Vis and electrochemical impedance spectroscopy, and cyclic voltammetry. The electrode displays excellent electrocatalytic activity towards uric acid (UA), ascorbic acid (AA) and dopamine (DA). Three resolved voltammetric peaks (at 183 mV for UA, 273 mV for AA and 317 mV for DA, all vs. Ag/AgCl) were found. Differential pulse voltammetry was used to simultaneously detect UA, AA and DA in their ternary mixtures. The linear working range extends from 10 to 3000 μM for UA; 0.1 to 2.5 μM, and 5.0 to 2 × 104 µM for AA; and 0.2 to 80.0 μM and 120.0 to 500 µM for DA, and the limits of detection (S/N = 3) are 0.1, 50.0, and 0.4 μM, respectively. The performance of the sensor was evaluated by analysing spiked human urine samples, and the recoveries were found to be well over 98.0% for the three compounds. These results indicate that the rGO-SPCE represents a sensitive analytical sensing tool for simultaneous analysis of UA, AA and DA.
Highlights
Uric acid (UA) is a principal end product of purine metabolism [1] and abnormal levels in urine and/or blood are symptomatic of diseases such as Lesch–Nyhan syndrome, gout and hyperuricemia, and renal and cardiovascular diseases [2]
Both graphene of oxide (GO) and reduced graphene oxide possess unique set of electrical
In order to evaluate the reproducibility of reduced graphene oxide (rGO)-screen-printed carbon electrode (SPCE), a single rGO-SPCE was used (n = 6) to determine the concentrations of the compounds in a ternary mixture (250.0 μM UA, 2.5 mM Ascorbic acid (AA), and 50.0 μM DA) by Differential pulse voltammetry (DPV)
Summary
Uric acid (UA) is a principal end product of purine metabolism [1] and abnormal levels in urine and/or blood are symptomatic of diseases such as Lesch–Nyhan syndrome, gout and hyperuricemia, and renal and cardiovascular diseases [2]. High levels of DA in human bodily fluids have been found to be associated with several neurological disorders including Huntington’s disease, restless legs syndrome, schizophrenia, attention deficit hyperactivity disorder and Parkinson’s disease [7,8]. Several analytical methods such as high performance liquid chromatography, chemiluminescence, UV-Vis spectroscopy, capillary electrophoresis and electroanalytical methods [9,10,11] have been developed for the detection of these compounds. Details of the sensor fabrication, characterization and application to the analysis of the compounds are described and discussed
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