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Chlorhexidine digluconate on chitosan-magnetic iron oxide nanoparticles modiļ¬ed electrode: Electroanalysis and mechanistic insights by computational simulations
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Resumo(s)
In this work, an electrochemical sensor based on modiļ¬cation of a glassy carbon electrode (GCE) with magnetic iron oxide nanoparticles (Fe3O4) and chitosan (CS) was developed to quantify chlorhexidine digluconate (CHD), a worldwide used antiseptic. Cyclic voltammetric and electrochemical impedance spectroscopy assays showed that the permeable Fe3O4/CS ļ¬lm on the GCE surface improved the conduc-tivity and facilitated electron transfer. CHD response at GCE/Fe3O4/CS corresponds to an irreversible anodic diffusion-controlled process (at about 1.13 V in 0.04 mol Lā1 Britton-Robinson buffer, pH 4.0) involving the transfer of two electrons and an equal number of proton. Quantum mechanics and Monte Carlo simulations were performed to give insights on the CHD oxidation process. The modiļ¬cation with Fe3O4/CS induced alterations in CHD geometry that led to degeneration of the highest occupied molecular orbitals (HOMO and HOMOā1), facilitating the oxidation process because both sides of the molecule contribute to these orbitals. It facilitated also, at least thermodynamically, the ļ¬rst electron lost. The oxidation of CHD probably conducts to the formation of two p-chloroaniline and, possibly, two biguanidine molecules. GCE/Fe3O4/CS exhibited suitable electroanalytical characteristics in terms of sensitivity (8.78 Ā± 0.58 A molā1 L), linearity range (2.10 Ć 10ā8ā2.09 Ć 10ā7 mol Lā1), detection limit (5.7 Ć 10ā9 mol Lā1; 0.005 mg kgā1), intra-day repeatability (2.8% RSD), and reproducibility (4.6% RSD). To evaluate the accuracy and applicability of the proposed electroanalytical methodology, two CHD com-mercial formulations were analysed and the attained results were in agreement with those attained by the chromatographic reference method. Overall, the developed GCE/Fe3O4/CS exhibits appropriate performance and relevant advantages for CHD electroanalysis in commercial products.
DescriĆ§Ć£o
Palavras-chave
Chlorhexidine Magnetic nanoparticles Chitosan Computational simulations Pharmaceuticals
Contexto Educativo
CitaĆ§Ć£o
Editora
Elsevier