Analytical & Bioanalytical Electrochemistry
Volume:14 Issue: 8, Aug 2022

Developing simple yet efficient sensors for drug-abuse detection is highly required from both human health and medical aspects. In this work, a glassy carbon electrode modified by a thin layer of poly L-arginine (P-L-Arg/GCE) was fabricated by electropolymerization of L-arginine monomer using cyclic voltammetry (CV) and then it was used for determination of Methadone (MET). The surface characteristics of the P-L-Arg/GCE was examined by scanning electron microscopy and electrochemical impedance spectroscopy. To study the electrochemical responses of MET on P-L-Arg/GCE and bare GCE, cyclic and differential pulse voltammetric techniques were employed. For P-L-Arg/GCE, a considerable enhancement in electrooxidation signal of MET was observed compared to bare electrode. The influence of various determinant parameters on P-L-Arg/GCE performance was studied. At optimized conditions, using DPV technique, the electrooxidation peak current was linear to MET concentration in the ranges of 0.49-2.98 µM and 2.98-11.9 µM with a detection limit of 0.32 µM. The utility of P-L-Arg/GCE was successfully validated by analyzing MET in serum and urine samples, representing its potential application for real samples analysis.

Cobalt ferrite nanoparticles (CFNs) were successfully synthesized by a wet chemical method. The morphology and that of the crystal structure of the synthesized nano ferrites was done by X-ray diffraction analysis and Transmission electron microscopy techniques. The crystalline size of the synthesized nanoparticles was in the range of 30 nm calculated by the Debye-Scherrer equation. A glassy carbon electrode (GCE) modified with the ferrite nanoparticles (CFNs) was employed for the electrochemical detection of dopamine using the techniques of cyclic voltammetry and differential pulse voltametry. The chemically modified electrode exhibited exceptional redox action for the detection of dopamine (DA), with a notable decline of overpotential while compared to bare GCE. The CFNs/GCE exhibited excellent stability, reproducibility and sensitivity in the determination of DA with a detection limit of 0.2 μm. The sensor exhibited appreciable electrocatalytic behavior in the simultaneous detection of ascorbic acid (AA), Dopamine (DA) and Uric acid (UA).

The electrode was fabricated by electropolymerization of 6-phenyl-1,3,5-triazine-2,4-diamine as a thin film on the surface of unmodified carbon paste electrode (UCPE) by using cyclic voltammetry. Superficial morphology of UCPE and improved electrode was traced by scanning electron microscopy (SEM). The constructed improved electrode shows admirable electrocatalytic movement for the analysis of dopamine (DA) and uric acid (UA) in 0.2 M phosphate buffer (PBS of pH7.4), which is attributed to increased active surface area. The fabricated electrode process was found to be diffusion controlled and it shows linear range from 10 to 90 μM for DA and 10 to 70 μM for UA and lower limit of detection (LOD) for DA and UA are established at 0.25 and 0.37 μM separately. The fabricated electrode was applied in analytical application in dopamine injection samples.

The yeast microbial fuel cells (MFCs) are promising energy conversion devices that use yeast as a biocatalyst to convert chemical energy to electrical energy. Yeast MFCs have garnered considerable interest due to their ability to create electrons, low cost, moderate functioning at ambient temperature, ease of growth, and specificity for substrates. The scientometric analysis of the Web of Science database was carried out to identify the historical research trend related to yeast MFC of 148 high-quality publications from 2005 to mid-2022. The detailed analysis starting with the notion of energy generation during fermentation. Noteworthy breakthroughs in the creation of electrode materials, mediator addition, and in-situ application of yeast MFCs are highlighted. The analysis results revealed that Asian researcher dominated the on yeast MFCs topic, with India and South Korea leading the way. Diponegoro University researcher has the most publications on yeast MFCs, while a researcher from Pennsylvania State University has the most citations. This article may help the yeast MFCs researchers to navigate the overview of this research area and identify the most significant articles, countries, researchers, potential transdisciplinary collaboration and prolific contribution by researcher on this topic. These findings also reveal the future of yeast MFC research trend.

Reduced graphene oxide was estimated for the modification of a glassy carbon electrode. The fabricated electrode was employed for folic acid determination in 0.1 M KCl solution (pH 14) using cyclic, linear sweep, differential pulse voltammetric and chronoamperometric techniques. The modified sensor exhibits a high electro-catalytic activity towards FA oxidation in the presence of ascorbic acid. The anodic peak current (IP) of FA increased linearly with an increase in pH (12.6–14) and scan rate (20–500 mV/s) at the ERGO/GCE. Good linearity was obtained between IP and FA concentrations (3.01–7.23 µM) with the detection (LOD) and quantification (LOQ) limits are 4.68 and 15.6 nM, respectively. Under diffusion control, the diffusion coefficient was estimated to be 2.88×10−6 cm2/s at the ERGO/GCE. The fabricated sensor gives high selectivity, good sensitivity and excellent reproducibility. Thus, the proposed method could be applied to detect FA in pharmaceutical formulations and urine samples.

A carbon-based electrode was modified through incorporating N, S, P and B quaternary-doped graphene (NSPBG) in its composition, and given that former studies indicated a selective interaction between cefixime (CEF) and Yb3+ ions in comparison to other lanthanide ions. Therefore, CEF was further incorporated in the CPE composed of a mixed matrix of NSPBG and graphite powder to develop an Yb3+ selective potentiometric carbon paste electrode, and evaluations of the modified CPE reflected that high sensitivity, selectivity; short response time and stability, as well as improved lifetime as opposed to CPEs based on the multiwall carbon nanotube (MWCNTs). The optimized electrode with a composition of 7% NSPBG, 13% CEF, 30% IL and 50 % graphite powder, had a Nernstian response of 19.7±0.1 mV per decade over the concentration range of 1.0×10-7 to 1.0×10-2 M.