Voltammetric determination of 4-nitrophenol using a glassy carbon electrode modified with a gold-ZnO-SiO2 nanostructure

Abstract

A nanostructured material of the type Au-ZnO-SiO is described that consists of ZnO and gold nanoparticles (NPs) dispersed into a silica matrix and used to construct a voltammetric sensor for 4-nitrophenol. The AuNPs and ZnO NPs are anchored onto the silica network which warrants the nanostructures to be stable in various environments. It also facilitates the electron transfer between the electrolyte and the glassy carbon electrode (GCE). The properties of the nanostructure as a modifier for the GCE were investigated by energy dispersive spectrometry, X-ray diffraction spectroscopy, and transmission electron microscopy. It is shown that the nanostructure increases the surface area. Hence, the cathodic and anodic current in differential pulse voltammetry of 4-nitrophenol are considerably enhanced in comparison to a bare GCE. Under optimum conditions, the currents for oxidation and reduction are proportional to the concentration of 4-nitrophenol in the 0.05-3.5 μM and 0.01-1.2 μM concentration ranges, with 13.7 and 2.8 nM detection limits, respectively. The sensor has excellent sensitivity, fast response, long-term stability, and good reproducibility. It is perceived to be a valuable tool for monitoring 4-nitrophenol in real water samples. Graphical abstract Schematic of voltammetric sensor for 4-nitrophenol. It is based on GCE modified with gold-ZnO-SiO nanostructure. It exhibited the improvement in performance for both oxidation and reduction peaks in terms of linearity, concentration range, detection limit, and sensitivity.

Colorimetric determination of p-nitrophenol by using ELISA microwells modified with an adhesive polydopamine nanofilm containing catalytically active gold nanoparticles

“…The optimized protocol was exploited to set up an original, high throughput in-plate method to quantify nitrophenols in aqueous solution, determining the main kinetic and analytical parameters. Finally, results on standard samples were directly compared with those obtained on spiked urine samples containing p-NPh, the main bodily fluid of interest for its monitoring[14][15][16][17][18].Dopamine hydrochloride (DA), hydrogen tetrachloroaurate trihydrate (HAuCl4•3H2O, >99.0%), Trizma hydrochloride (Tris-HCl, >99.0%), sodium borohydride (NaBH4), o-nitrophenol, m-nitrophenol, pnitrophenol, and o-aminophenol were all purchased from Sigma-Aldrich (Milan, Italy, www.sigmaaldrich.com/italy). All chemicals were used as received without any further purification.…”

Silver Nanoparticles‐Silsesquioxane Nanomaterial Applied to the Determination of 4‐Nitrophenol as a Biomarker

“…According to previous studies, the reduction peak may be related to the reduction of the nitro groups of the 4‐NP, via an irreversible 4 e − /4 H + electrochemical reduction reaction .…”

“…The advent of electrodes modified with metal nanoparticles in combination with efficient stabilizing agents has contributed to this demand. Electrodes modified with nanomaterials allow lower costs in comparison to bare electrodes while enhancing the selectivity and sensitivity and even providing electrocatalysis in some reactions .…”

A Gr/αFe2O3/Carbon Paste Electrode Developed as an Electrochemical Sensor for Determination of Rizatriptan Benzoate: An Antimigraine Drug

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