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In this study, MoSe2/rGO nanocomposite modified screen printed graphite electrode (SPGE) was designed for acyclovir (ACV) determination. The electrochemical investigation and measurement of ACV were performed by applying some voltammetric techniques and chronoamperometry. After modification of SPGE, the enhancement of the voltammetric response and the reduction of overpotential of ACV confirmed the good electrocatalytic ability of MoSe2/rGO/SPGE sensor towards the ACV oxidation. The voltammetric method (differential pulse voltammetry (DPV)) was used to investigate the determination ability of MoSe2/rGO nanocomposite/SPGE towards ACV determination under the optimum parameters and conditions. The MoSe2/rGO/SPGE sensor indicated appreciable sensing ability towards ACV, with an optimal linear response from 0.03-190.0 µM and a limit of detection (LOD) of 0.01 µM. More importantly, the practical applicability of the designed sensor was confirmed in the ACV quantification in ACV tablet and urine samples, showing its potential application for real sample analysis.

Cancer, is a worldwide epidemic, is characterized by the abnormal growth of cells and their ability to spread to various organs and tissues within the body. Doxorubicin (DOX) is an effective chemotherapy drug that not only inhibits the growth of cancer cells, but also assists in the immune-mediated elimination of tumor cells. Hence, it is critical to carefully regulate the DOX dosage for cancer patients undergoing drug-based cancer treatment. Nowadays, electrochemical sensors have emerged as reliable analytical instruments for detecting a broad spectrum of target molecules. This is because of their simplicity, affordability, and ability to seamlessly integrate with multiplexed and point-of-care strategies. By modifying the surface of electrodes with diverse materials, it is possible to enhance the sensitivity and lower the detection limits (LOD) of electrochemical sensors. This report provides a concise summary of selected studies that focus on the use of electrochemical sensors based on carbon nanomaterials and polymers for the DOX analysis, and offers insights on the technical advancements and potential future applications in this particular domain.

In this work, three dimensional NiO nanowrinkles (3D NiO-NWs) were prepared and used as electrode materials to modify the surface of a glassy carbon electrode (3D NiO-NWs/GCE). Then, differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CHA) were employed to determine the electrochemical response of theophylline on as-fabricated sensor. The electrochemical theophylline oxidation was elevated on the modified electrode. The peak current on the modified electrode in phosphate buffer solution (PBS, 0.1 M, pH=7.0) showed a linear elevation with an increase in the theophylline concentration (0.1-900.0 µM), with a narrow detection limit of 0.03±0.001 µM.

In this work, nanolayered Ti3C2 was applied to construct a modified screen printed electrode (SPE). This modified electrode (Ti3C2/SPE) was applied for detecting tyrosine with various voltammetric procedures. Modifying the working electrode increased electro-oxidation of tyrosine as the current intensity enhanced. Moreover, Ti3C2/SPE was employed for determining tyrosine in concentration ranges from 0.5-700.0 μM with the low LOD of 0.15 μM using DPV.

The present study reports synthesis of MOWS2 nanocomposite followed by its characterization using energy dispersive X-ray spectroscopy (EDS), X-Ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Chronoamperometry (CHA), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) have been used to examine electro-chemical behaviors of sulfite on MOWS2 nanocomposite modified SPE. Electro-chemical specification indicated very good electro-catalytic activities and surface area impact of MOWS2 nanocomposite. Oxidation signals of sulfite on MOWS2/SPE has been considerably increased in comparison to the bare SPE. Within optimum conditions, quantification of sulfite might range between 0.08 to 700.0 µM with a small determination limit of 0.02 µM based on S/N=3.The impact of scan rates has been explored. Finally, the MOWS2/SPE has been employed for detection of sulfite in real specimens. In general, an easy experimental method for manufacturing MOWS2 nanocomposite has been suggested that takes advantage of selectivity, reproducibility, and sensitivity toward electro-active specimens, as well as biological matrices.

In the present work, a new sensor for morphine (MO) measurement, based on modification of screen-printed carbon electrode (SPE) by using magnetic core shell manganese ferrite nanoparticles was reported. The electrochemical behaviour of MO was investigated in phosphate buffer solution (pH 7.0) by voltammetry. The electrochemical response of the modified electrode toward morphine was studied by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA). The modified electrode displayed a decrease in the overpotential (ca. 80 mV) and an obvious increase in the peak current was observed compared to the non-modified SPE. The results indicated that modified screen-printed electrode enhanced electrocatalytic activity towards the oxidation of MO. Under the optimized conditions the calibration curve for MO was linear from 0.1 – 600.0 μM and the detection limit based on 3Sb/m was 0.02 µM. The application of the proposed method in analysis of real sample was also evaluated and satisfactory results were obtained.

In this study, the La3+/Co3O4 nanoflowers were synthesized by co-precipitation method. The morphology of the La3+/Co3O4NFs were characterized using scanning electron microscopy (SEM), and were further used to modify the graphite screen printed electrode (GSPE). The electrochemical behavior of acetaminophen at La3+/Co3O4NFs/GSPE has been studied in aqueous solutions. Experimental results showed that the La3+/Co3O4NFs modified GSPE possess excellent electrocatalytic activity toward the detection of acetaminophen. Under optimum conditions, the La3+/Co3O4NFs modified electrode exhibited high sensitivity and stability to acetaminophen over a wide linear range of concentrations from 0.5μM to 250.0μM, with a detection limit of 0.09μM. Finally, the proposed sensor was successfully applied to the detection of acetaminophen in real samples.

This paper gives a comprehensive review about the most recent progress in graphene and graphene oxide based electrochemical sensors and biosensors. Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). The application of graphene and graphene oxide in the modification processes leads to improved sensitivity, electrocatalytic behavior, and reduced fouling. The development of graphene and graphene oxide based sensors in biosensing and detection of chemicals have been resulted in great achievements towards more sensitive health care instruments and preventing the environmental problems. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this paper.

A novel electrochemical sensor was proposed for the determination of amitriptyline based on the copper oxide (CuO) nanoparticles modified graphite screen-printed electrode. CuO nanoparticles were used to enhance the surface area of the electrode and then improve the sensitivity of the electrochemical sensor.
Amitriptyline electrochemical response characteristics of the modified electrode in a phosphate buffer solution (PBS) of pH 7.0 were investigated by cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The linear range for the detection of amitriptyline was changed from 1.0 µM to 200.0 μM with the detection limit of 0.4 μM (S/N=3). Finally, the proposed method was applied to measure amitriptyline in real samples. It was shown that the proposed sensor exhibited significant promise as a reliable technique for the detection of amitriptyline in real samples.

Paracetamol is a non-steroidal anti-inflammatory drug used as an antipyretic agent for the alternative to aspirin. Conversely, the overdoses of paracetamol can cause hepatic toxicity and kidney damage. Hence, the determination of paracetamol receives much more attention in biological samples and also in pharmaceutical formulations. Here, we report a rapid and sensitive detection of the paracetamol based on screen-printed modified electrode (SPE) with Cu nanocomplex (Cu) in pH=7.0. The paracetamol is not stable in strong acidic and strong alkaline media, and is hydrolyzed and hydroxylated. However, it is stable in intermediate pHs due to the dimerization of paracetamol. The kinetics of the paracetamol oxidation was briefly studied and documented in the schemes. In addition, the characterization of Cu nanocomplex was probed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Moreover, the voltammetry determined the paracetamol with the linear concentration ranging from 10.0 to 1000.0 μM and the lower detection limit of 1.0 μM. This method was also successfully used to detect the concentration of paracetamol in pharmaceutical formulations and urine samples.