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 cm(2). The low charge transfer resistance (197.7 Omega), 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 mu M. 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.