Electroanalytical Performance of a Carbon Paste Electrode Modified by Coffee Husks for the Quantification of Acetaminophen in Quality Control of Commercialized Pharmaceutical Tablets

Electrochemical determination of acetaminophen (APAP) was successfully performed using a carbon paste electrode (CPE)modified with coffee husks (CH-CPE). Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray spectroscopy (SEM-EDX) were, respectively, used for the morphological and elemental characterization of coffee husks prior to their utilization. Theelectrochemical oxidation of APAP was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and squarewave voltammetry (SWV). SWV technique appeared to be more sensitive since the oxidation current of APAP was twofold higherwith the CH-CPE sensor than with the bare CPE, in relation to the increase in the organophilic character of the electrode surface.Furthermore, on CH-CPE, the current response of APAP varied linearly with its concentration in the range of 6.6????M to 0.5 mM,leading to a detection limit of 0.66????M(????/????=3). Finally, the proposed CH-CPE sensor was successfully used to determine theamount of APAP in commercialized tablets (Doliprane�500 and Doliprane 1000), with a recovery rate ranging from 98% to 103%.This novel sensor opens the way for the development of low-cost and reliable devices for the electroanalysis of pharmaceuticalformulations in developing countries

Sample Preparation Techniques for Electrochemical Analysis of Pesticides and Heavy Metals in Environmental and Food Samples

The development of an analytical methodology commonly includes sampling and sample pretreatment-preparation. The sample preparation step should provide the analytes (pesticides, heavy metals, drugs, dyes…etc.) in an adequate medium (typically aqueous or non-aqueous solution) to be detected and/or quantified. It is, therefore, necessary to ensure that the sample is homogeneous and free of interferents, as long as the preparation step is the most significant source of error in the analytical method development and is the most time-consuming step especially when solid samples are analyzed. Given its importance, this preparation step has a fundamental importance in the overall analytical method development, mainly when electroanalytical methods are applied. In this chapter, the steps involved in preparing samples for electrochemical analysis will be described in detail. Specifically, we will be focusing on the sample preparation techniques for the electrochemical analysis of pesticides and heavy metals, in environmental and food samples. For non-electrochemical readers, a brief introduction to the most commonly used electroanalytical methods will be described

LuIII bisphthalocyanines as mediators for redox reactions at thin-organic-film modified electrodes

Lutetium bisphthalocyanines, dissolved in a thin-film of nitrobenzene covering a graphite electrode, have already been used for ion transfer studies across the liquid∣liquid interface. These sandwich complexes are also good candidates for the electron exchange with species in water, across the interface. Their one-electron oxidation and reduction are fully reversible, the oxidized and reduced forms being chemically stable. Compared with ferrocene derivatives and porphyrins that have been extensively used previously, these compounds offer very interesting properties for the mediation of electron exchanges with redox species in aqueous solutions. Keywords: Lutetium bisphthalocyanines, Modified electrode, Thin-organic-film, Electron transfer, Liquid∣liquid interface, Catalysi