Amperometric Highly Sensitive Uric Acid sensor Based on Manganese(III)porphyrin-Graphene Modified Glassy Carbon Electrode

•GO-MnNH2TPP/GCE holds excellent electrocatalytic activity and high selectivity towards UA.•DPV and amperometric i-t curve technique were used to detect UA.•The linear relationship has been well built by both DPV and amperometric i-t curve technique.•GO-MnNH2TPP/GCE was sensitive for the detection of UA.

The glassy carbon electrode (GCE) modified with 5-(4-Aminophenyl)-10,15,20-triphenylporphyrin]Mn(III) (MnNH2TPP) and graphene oxide (GO) composite materials (GO-MnNH2TPP) was investigated by electrochemical impedance spectroscopy (EIS) and successfully employed for the determination of uric acid (UA). Electrochemical behaviors of UA at various electrodes including the glassy carbon electrode, GO/GCE, MnNH2TPP/GCE and GO-MnNH2TPP/GCE were measured, respectively, which showed GO-MnNH2TPP/GCE had better electrocatalytic activities than other electrodes under the present experimental conditions. The experimental conditions of the UA determination including the effects of scan rate, pH value and the modified amount of GO-MnNH2TPP on the surface of GCE were optimized when the GO-MnNH2TPP/GCE was used to detect UA. The electrochemical response properties of UA were studied by two electrochemical methods including the differential pulse voltammograms (DPV) and the amperometric i-t curve technique under above optimized experimental conditions. The response of GO-MnNH2TPP/GCE towards UA was excellent line relationship in the concentration ranges from 0.5 to 500 μM and the lowest detection limit was 0.30 μM (S/N = 3) by DPV; the amperometric i-t curve techniques also exhibited excellent line relationship in the concentration ranges from 20 to 290 μM and the lowest detection limit was 1.74 μM (S/N = 3). These results showed the GO-MnNH2TPP/GCE hold excellent electrocatalytic activity, good stability and high selectivity towards UA.

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