Exploiting synergistic effects: Cheap ultra-sensitive electrochemical rutin detection using WO3/rGO nanocomposite in combination with multiwalled carbon nanotubes

Abstract

Multiwalled carbon nanotubes (MWCNTs) are extensively studied due to their enhanced signal response, improved stability, selectivity, and versatility in fabrication, especially combined with designed materials; however, costly and time-consuming preparation are obstacles to their implementation in routine analyses. Therefore, we propose a tungsten oxide (WO3) and reduced graphene oxide (rGO) nanocomposite (WO3-G/MWCNT) that was mixed with MWCNTs and presented interesting results. We prepared the nanocomposite using a fast and facile route using in situ generated atomic hydrogen species; also, it was easily characterized by Scanning Electron Microscopy, Raman, and X-ray Spectroscopy. The nanocomposite was deposited on a glassy carbon electrode (GCE) and investigated as a voltammetric sensor for ultra-sensitive rutin quantification; a synergic effect towards rutin oxidation was observed by a 30-fold current increase in comparison to the bare GCE. Under optimized conditions, square wave voltammetry was performed, presenting a linear range from 0.183 to 2.849 µmol/L. The limits of detection and quantification were 9.00 and 65.00 nmol/L, respectively. High selectivity was noticed in quantifying 1.75 µmol/L rutin in the presence of ascorbic acid, citric acid, caffeine, glucose, and naringenin, which was attributed to the high signal response and sensitivity of WO3-G/MWCNT/GCE. High accuracy was also noticed for determining rutin in synthetic human serum and commercial plasma samples, with a recovery range of 85.5–108.7%. Those results confirm that the easy fabrication of WO3-G/MWCNT can be an excellent alternative for manufacturing ultra-sensitive sensors with promising features to be explored for drug monitoring and quality control of pharmaceuticals.