Simultaneous differential pulse voltammetric detection of uric acid and melatonin based on a self-assembled Au nanoparticle–MoS2 nanoflake sensing platform

Abstract

In this work, rapid construction of an electrochemical sensing platform based on self-assembled gold nanoparticles (Au NPs) on MoS2 nanoflakes (NFs) was achieved by probe sonication process. The contemporary study dealt with the first electrochemical sensor (Au-MoS2) to detect UA and MT simultaneously through differential pulse voltammetry (DPV). The developed Au-MoS2 sensing platform was dropped-cast on the glassy carbon electrode (GCE) and the high surface to volume ratio of Au-MoS2 enhanced the electrochemical active surface area (EASA) of GCE to 0.980 cm2. The low charge transfer resistance (197.7 Ω), the high conductivity of Au-MoS2 nanocomposite and the synergistic effect between the Au NPs and MoS2 NFs accelerates the electron transfer at Au-MoS2 modified GCE interface. The high electrocatalytic activity and the large surface area at the Au-MoS2 influenced the simultaneous electrochemical detection of uric acid (UA) and melatonin (MT) with limits of detection of 18.2 and 15.7 nM, respectively, in the linear range of 0.033–10.0 μM. The developed sensor had high selectivity, precise reproducibility, excellent repeatability, and good stability (operational and storage). Under optimized conditions, spiking of UA and MT was performed in a urine sample, and the calculated recoveries were in the range of 92.0 %–105.6 %. Owing to the advantages of the simple Au-MoS2 sensing platform, simultaneous electrochemical detection of other electrochemical active species may be possible by optimizing the sensing platform for different conditions.