Electrochemical sensor based on low silica X zeolite modified carbon paste for carbaryl determination

A new and simple approach for carbaryl determination in natural sample was proposed using Low Silica X (LSX) zeolite modified carbon paste electrode. LSX zeolite with a porous structure was incorporated into carbon paste electrode in the appropriate portion. The prepared electrode was then characterized using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters as the zeolite amounts, pH, accumulation time, and differential pulse voltammetric parameters were optimized. Under optimal conditions, a linear response was obtained in the range of 1-100 µM of carbaryl using differential pulse voltammetry with detection limit of 0.3 µM (S/N = 3). The sensors showed good selectivity, stability, and reproducibility and has been successfully applied for detection of carbaryl in tomato samples with good recoveries.

Electrochemical behaviour and voltammetric determination of p-phenylenediamine at carbon paste electrode

<p class="PaperAbstract"><span lang="EN-GB">An electrochemical method was developed for voltammetric determination of p-phenylenediamine using a carbon paste electrode (CPE). The electrode exhibited the highest electrocatalytic activity toward oxidation and reduction of p-phenylenediamine in the phosphate buffer, pH 7 solution. After optimizing the experimental conditions and square wave voltammetry parameters, a linear current response toward concentration of p-phenylenediamine was obtained in the range of 0.12–3.00 µM with detection limit of 0.071 µM. The proposed procedure was successfully applied for determination of the total p-phenylenediamine content in the takeout extract sample.</span></p>