Simultaneous and sensitive determination of ascorbic acid, dopamine and uric acid via an electrochemical sensor based on PVP-graphene composite

TLDR

High‑sensitivity, accurate, rapid methods are increasingly needed for simultaneous detection of ascorbic acid, dopamine, and uric acid. This study presents a simple, sensitive electrochemical sensor based on a PVP‑graphene composite film on a glassy carbon electrode for simultaneous detection of AA, DA, and UA. The sensor uses a PVP‑graphene composite film on a glassy carbon electrode and employs second‑order derivative linear sweep voltammetry for measurements. The PVP‑GR/GCE sensor exhibited excellent electrocatalytic activity, resolving AA, DA, and UA with peak potential separations of 212, 130, and 342 mV, low overpotentials, and high peak currents; it achieved linear ranges of 4 µM–1 mM (AA), 0.02–100 µM (DA), and 0.04–100 µM (UA), detection limits of 0.8 µM, 0.002 µM, and 0.02 µM, respectively, and demonstrated high sensitivity, selectivity, reproducibility, stability, and successful application to real samples.

Abstract

Abstract A method with high sensitivity, good accuracy and fast response is of ever increasing importance for the simultaneous detection of AA, DA and UA. In this paper, a simple and sensitive electrochemical sensor, which based on the polyvinylpyrrolidone (PVP)-graphene composite film modified glassy carbon electrode (PVP-GR/GCE), was presented for detecting ascorbic acid (AA), dopamine (DA) and uric acid (UA) simultaneously. The PVP-GR/GCE has excellent electrocatalytic activity for the oxidation of AA, DA and UA. The second-order derivative linear sweep voltammetry was used for the electrochemical measurements. The peak potential differences of DA-AA, DA-UA, and UA-AA (measured on the PVP-GR/GCE) were 212, 130 and 342 mV respectively. Besides, the over potential of AA, DA and UA reduced obviously, so did the peak current increase. Under the optimum conditions, the linear ranges of AA, DA and UA were 4.0 μM–1.0 mM, 0.02–100 μM, and 0.04–100 μM, respectively. The detection limits were 0.8 μM, 0.002 μM and 0.02 μM for AA, DA, and UA. The electrochemical sensor presented the advantages of high sensitivity and selectivity, excellent reproducibility and long-term stability. Furthermore, the sensor was successfully applied to the analysis of real samples.