Mechanistic aspects of uncatalysed and Os(VIII) catalysed oxidation of 5-flourouracil – An anticancer drug by alkaline diperiodatoargentate(III)

Electrochemical investigation of an anticancer drug 5-Fluorouracil in the presence of Theophylline using low-cost and disposable poly(GLY) modified pencil graphite electrode

Herein this study, a facile, efficient and disposable electrochemical sensor has been prepared by electropolymerization of glycine (poly(GLY)) on the surface of pencil graphite electrode (PGE). The surface topology of the equipped poly(GLY) modified pencil graphite electrode (poly(GLY)/PGE) and bare pencil graphite electrode (BPGE) has been characterized by the scanning electron microscopy (SEM) combined with energy dispersive x-ray analysis (EDX) and charge transfer behaviour was measured by electron impedance spectroscopy (EIS) method. The voltammetric behaviour of anticancer, 5-fluorouracil (5-FU) in the presence of theophylline (THP) has been carried out in 0.1 M phosphate buffer solution (PBS) of physiological pH 7.0 using different techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The proposed poly(GLY)/PGE shows augmented peak current for 5-FU at lower potential side over the BPGE due to the electrocatalytic behaviour of modifier layers wrapped on the electrode surface. The kinetic behaviour of 5-FU at modified electrode surface was studied by varying different parameters such as pH, scan rate and concentration study in 0.1 M PBS used as a supporting electrolyte. The limit of detection (LOD) for 5-FU was attained using DPV method with different concentrations (1.0-13.0 μM) and it was found to be 0.012 μM. The possible electrochemical reaction of 5-FU was proposed and it was incorporated by two electrons and two protons mechanism at modified electrode surface. The voltammetric response of poly(GLY)/PGE towards the determination of 5-FU was unaffected in the presence of some excipients in addition to the remarkable stability and reproducibility. The applicability of the proposed sensor has been performed by real sample investigation of 5-FU with a substantial percentage of recovery results in all optimized conditions.

Electrocatalytic detection of herbicide, amitrole at WO3·0.33H2O modified carbon paste electrode for environmental applications

Environmental pollution by the heavy usage of pesticides has been a pandemic issue in view of the rising farming operations for increasing the crop yield to meet the requirements of food chain supply. Throughout the world, environmental pollution by the presence of pesticides, particularly the use of herbicides in large quantities to protect the crops, has posed many environmental issues. In this research, an electrochemical sensor based on tungsten oxide hydrates (WO₃·0.33H₂O) nanorod modified carbon paste electrode (CPE) was developed for the detection of herbicide, amitrole (AMT) by the cyclic voltammeter. Hydrothermally synthesized and characterized WO₃·0.33H₂O nanorod was found to be sensitive towards the detection of AMT due to its superior sensing property as the sensor showed enhanced current and catalytic property when used in phosphate buffer solution (PBS) of pH 5.0 by the cyclic voltammetric (CV) and square wave voltammetric (SWV) techniques. The influence of electro kinetic parameters viz., scan rate, pH, accumulation time and temperature with respect to AMT oxidation was studied using CV. The linearity range was in between 1.0 × 10^-8 M and 24 × 10^-5 M and limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 2.33 nM and 7.8 nM respectively. The proposed simple method demonstrated the potential applicability to detect AMT from the soil and water samples.