Sphere-like Ni3S4/NiS2/MoOx composite modified glassy carbon electrode for the electrocatalytic determination of D-penicillamine

This article describes the synthesis of Ni3S4/NiS2/MoOx composite as an electrode material for the electrocatalytic sensor for D-penicillamine (D-PA). The detection of D-PA is important in biodiagnostics and therapeutic dosage control. The present study compared the performance of Ni3S4/NiS2/GC and Ni3S4/NiS2/MoOx/GC electrodes for the electrocatalytic detection of D-PA. The nickel sulfide phases containing MoOx demonstrated two-fold higher catalytic current response than the controlled one (Ni3S4/NiS2/GC). The excellent performance of the Ni3S4/NiS2/MoOx/GC electrode is confirmed by electrochemical parameters, such as electrochemical charge transfer resistance (133 Omega), diffusion coefficient (3.569 x 10(-6) cm(2) s(-1)), and catalytic rate constant (7.415 x 10(5) M-1 s(-1)). The Ni3S4/NiS2/MoOx/GC electrode exhibited wide concentration detection of D-PA from 5 to 796 mu M with high sensitivity (0.08 mu A mu M-1), low limit of detection (0.26 mu M), and good interference tolerance ability. The proposed electrode was also successfully utilized towards D-PA detection in human urine samples, wherein good recovery ranges (105.6 and 103.5%) were obtained. (C) 2020 Elsevier B.V. All rights reserved.