Analytical & Bioanalytical Electrochemistry
Volume:15 Issue: 4, Apr 2023

In the present work, the BiVO4 nanoparticles (BiVO4/NPs) were synthesized using the co-precipitation method and characterized by the X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) techniques. The BiVO4/NPs were utilized as electrode modifiers with carbon paste electrode (BiVO4/MCPE), and the as-prepared modified electrode surface was pretreated with NaOH (BiVO4/NaOH/MCPE). The pretreated modified electrode was used for the simultaneous determination of acetaminophen (ACOP) and adrenaline (AD) by using cyclic voltammetry (CV) and differential pulse voltammetric (DPV) techniques. The influence of variation of concentration of ACOP and AD was investigated at BiVO4/NaOH/MCPE. The limit of detection (LOD) and limit of quantification (LOQ) of both ACOP and AD at BiVO4/NaOH/MCPE, respectively were determined, the LOD was found to be 3.3 µM for ACOP and 5.9 μM for AD, and LOQ was found to be 11.1 µM for ACOP and 17.8 μM for AD, respectively. Moreover, the BiVO4/NaOH/MCPE is used for the sensitive and selective determination of ACOP and AD in real samples.

Timely, efficient on-site detection of pesticides such as methyl parathion (MP) is crucial to ensure public health. This study introduces the first disposable electrochemically reduced graphene oxide (ErGO) modified electrode for rapid MP detection. A square wave anodic stripping voltammetry method for the detection of MP was developed using these ErGO-modified carbon screen-printed electrodes.  Based on this study, graphene’s high electric conductivity and unique structure enhanced the sensitivity of the electrode for MP detection.  Following optimization of the pH, equilibrium period, deposition potential, and period, the methodology demonstrated high sensitivity and reproducibility. Using the enhanced experiment conditions, calibration experiments were performed with a concentration range of 0 to 150 µg L-1 of MP. A consistent oxidation peak was observed at -0.180 V. The calibration data showed the increase in the peak height was linearly correlated to the increase in MP concentration, with a correlation coefficient of 0.9854. The sensitivity of the developed methodology was 0.0887 µA (µg L-1)-1, and the limit of detection was 9.06 µg L-1. The methodology was successfully applied to multiple water samples, specifically river water, groundwater, and General Test Water, with recovery rates of 106.01% (standard deviation = 1.46%), 109.51% (standard deviation=0.44%), and 97.69% (standard deviation=1.49%), respectively.

The electrochemical properties of Allura red on a glassy carbon electrode modified with the electrochemically reduced graphene oxide (ErGO/GCE) was investigated by cyclic voltammetry and differential pulse adsorptive anodic stripping voltammetry. The ErGO/GCE was fabricated of electrochemical reduced method in conditions: Graphene oxide was dispersed in water and electrochemically reduced for 15 cycles, potential scan range from 0 V to -1.5 V, scan rate 30 mV.s-1. The electrochemical behaviors of Allura red on the ErGO/GCE are semi-reversible oxidation and the Allura red had adsorptive on the surface of ErGO/GCE. The optimal conditions for determination of Allura red were Britton-Robinson buffer pH = 2.5, adsorption potential 0.5 V, adsorption time 15 s, and scanning rate 12.5 mV.s-1, linearity range from 10-7 mol.L-1 to 8×10-7 mol.L-1. The limit of detection (LOD) is 2.8×10-8 mol.L-1 and limit of quantification is 9.3×10-8 mol.L-1. The ErGO/GCE was successfully used in the determination of Allura red content in food samples with high sensitivity and accuracy, simple and low cost.

Herein, an electroplating method has been developed in order to improve the anti-corrosion properties of steel. Ni-based compounds to which solid Al2O3 particles have been electrochemically inserted. Nickel-alumina mixtures were deposited on steel substrates from the electroplating bath using different concentrations of Al2O3. The electrochemical corrosion tests of the samples were carried out in two different solutions 0.5 M K2SO4 and 0.5 M NaCl. Structural and morphological analyzes were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled to microanalysis (EDAX) analyses respectively. The electrochemical behavior of co-electrodeposited coatings (Ni-Al2O3) in corrosive solutions was followed using potentiodynamic methods and electrochemical impedance spectroscopy (EIS). The various tests carried out under working conditions revealed that the Al2O3 particles added to the bath have a beneficial effect on the electrochemical behavior of the steel by reducing its tendency to corrosion. In this work, we were also able to determine the optimal concentration leading to significant inhibition of the steel tested. This synthesized and studied concentration related to Al2O3 was evaluated at around 20 g.L-1.

The presence of various antioxidants in the ethanolic extract of Peganum harmala L. (EEH) seeds with different oxidation potentials was confirmed by cyclic voltammetry. The evaluation of the inhibition efficiency of the extract on zinc corrosion in the hydrochloric acid medium was carried out by gravimetry and electrochemical techniques. The results showed that the extract has satisfactory corrosion-inhibiting properties and that its efficiency is controlled by its concentration and medium temperature. The inhibition rate reached 96.8% in the presence of 2200 ppm of the EEH extract at 298K. The potentiodynamic polarization study showed that the extract is classified as a mixed-type inhibitor with a cathodic predominance. A good agreement between the results of the gravimetric study and those of the electrochemical measurements was demonstrated. The studied extract acts by physical adsorption, as indicated by the thermodynamic parameters, and follows the Langmuir model. The inhibition efficiency of the studied extract was improved in the presence of KI through a synergistic effect.

A new electrochemical biosensor based on Fe3O4 nanoparticles and molecularly imprinted polymer-modified screen-printed carbon electrode (SPCE) was built to record the HGH molecules. The HGH is an important metabolic hormone and is responsible for body growth, stimulating the growth and differentiation of muscle, bone, and cartilage. A stable SPCE/Fe3O4/Poly-pyrrole/MIP layer was formed by the electro-polymerization of pyrrole molecules as functional monomers and HGH as template molecules. The accuracy and sensitivity of the prepared SPCE were confirmed using the electrochemical impedance spectroscopy (EIS) technique. According to the results, the MIP showed a linear range of 1×10-6 to 1×10-11 g/cm3 for the HGH under study conditions with a limit of detection (LOD) of 2.927×10-12 g/cm3. The calibration curve showed 99.9% correlation of the data. It can be concluded that the MIP made for HGH molecules has high sensitivity and stability, low cost, short response time, and excellent reproducibility.