An Exfoliated Graphite Based Electrochemical Sensor for As(III) in Water

Abstract

In this work, we present the application of an exfoliated graphite electrode modified with gold nanoparticles (AuNPs) for the detection of As(III) in acidic media. Gold nanoparticles were deposited on the surface of an exfoliated graphite electrode by electrodeposition at a potential window of −0.2 V to 1.2 V. This was followed by activation in 0.5 M H2SO4 with 10 cycles from 0.6 V to 1.4 V. The modification of exfoliated graphite (EG) showed an increased electroactive surface area of the electrode and improved peak current output in a Fe(CN)63−/4− redox probe. EG‐AuNPs electrode was used to detect As(III) in 1.0 M HNO3 using square wave anodic stripping voltammetry (SWASV) technique at optimum conditions of pH 3, deposition potential of −0.8 V, deposition time of 180 s, frequency of 5 Hz and pulse amplitude of 50 mV. The EG‐AuNPs electrode detected As(III) in solution to a limit of 0.58 ppb with regression of 0.9993. The method reported is simple, cheap and possesses good reproducibility. The developed electrochemical sensor was applied in the detection of As (III) in an industrial real water sample. The results of the real water sample analysis from the developed method are comparable with the inductively coupled plasma – optical emission spectroscopy (ICP‐OES) results.

Optimization of Square Wave Voltammetry (SWV) Parameters by Design of Experiment (DoE) Methodologies for the Determination of Mifepristone at Glassy Carbon Electrode (GCE)

“…The characteristic reversible electrode process observed was further established by computed ratio ( I pa / I pc ) of 1.128. This value is close to unity and confirms the reversibility of the electrochemical system performed under the studied experimental conditions [30, 31]. While both cathodic reduction and anodic oxidation behaviour of mifepristone peak currents were detected using CV, we have exploited anodic oxidation as the basic principle of detection by SWV for optimization process.…”

A Silver-Loaded Exfoliated Graphite Nanocomposite Anti-Fouling Electrochemical Sensor for Bisphenol A in Thermal Paper Samples

“…These XRD peaks are attributed to the characteristic diffraction peaks of graphite and crystal phase, which are in agreement with previous reports. 24 , 31 For the AgNPs-EG nanocomposite ( Figure 1 e and inset), well-defined peaks were observed at 2θ = 37.74, 44.27, 64.10, 77.25, and 86.83°, corresponding to (111), (200), (220), (311), and (222) planes of the face centered cubic (fcc) structure of metallic silver, respectively (JCPDS 04–0783) 15 , 32 − 34 while still retaining the characteristic peaks of EG.…”

“…The above works motivates this paper, where silver nanoparticles were composited with exfoliated graphite (EG) for the fabrication of an electrochemical sensor for BPA detection. EG, possessing properties such as high electrical conductivity and electron transport, mechanical strength, and high surface area, has made a niche for itself as a suitable candidate for various applications, particularly as a substrate in electrochemistry. − With compressibility and mechanical strength, EG can be easily compacted into a working electrode that allows surface regeneration by polishing on emery paper, as a way of tackling fouling. Based on these inherent properties of both EG and AgNPs, as well as the motivation from the above works, we report the use of an AgNPs-EG nanocomposite-based electrode for the development of an electrochemical sensor for BPA detection in thermal paper samples.…”

Electrochemical detection of selected heavy metals in water: a case study of African experiences

“…Mafa and co-workers 141 also employed the SWASV to inspect the presence of As( iii ) in industrial influent and effluent water samples in South Africa, using the same eGE modified with gold nanoparticles (Au NPs) ( Fig. 6 ).…”