Electrocatalytic Determination of Salicylic Acid on Ni–Cr Alloy Modified Glassy Carbon Electrode

Abstract

Co-deposited nickel–chromium (Ni–Cr) onto the glassy carbon electrode (GCE) is successfully used as new amperometric sensor for the determination of salicylic acid (SA). SA is detected by a surface catalyzed oxidation, involving nickel(III) oxyhydroxides in alkaline solution. The performance of the biosensor Ni–Cr/GCE is characterized by cyclic voltammetry, chrono-amperometry, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The electrochemical behavior of the Ni–Cr alloy is qualitatively similar to that of pure nickel electrode. However, it is proposed that a higher degree of disorder of the oxyhydroxide layer structure is present on the top of the alloy. The electroactivity of Ni–Cr/GCE is studied as a function of the molar fraction (Xf%) of Cr3+ in the deposition bath. The results show that Ni–Cr/GCE exhibits a high electrocatalytic activity for SA oxidation. The Ni–Cr/GCE with 28Xf% Cr3+displays the best activity with a high response signal, a good sensitivity of 71.22 μA mM–1, a low detection limit of 0.1 μM (S/N = 3) and a fast response time (<3 s). Moreover, the reproducibility, selectivity and applicability of this electrochemical sensor are satisfactory evaluated.