Square wave voltammetric determination of Dexamethasone on a multiwalled carbon nanotube modified pencil electrode

Abstract

O comportamento eletroquímico de dexametasona, um hormônio esteroidal, foi estudado em um eletrodo de grafite modificado por nanotubos de carbono de camadas múltiplas, por voltametria de onda quadrada e espectroscopia de impedância eletroquímica. Dexametasona mostrou um pico de oxidação com potencial em torno de + 0,80 V na superfície do eletrodo modificado. Sob condições ótimas, a corrente de pico de oxidação depende da concentração da dexametasona e foi linear no intervalo de 0,15-100 μmol L -1 de dexametasona com um limite de detecção de 0,09 μmol L -1 de dexametasona. Os efeitos de substâncias interferentes potenciais na determinação de dexametasona foram investigados e encontrou-se que o sensor proposto é sensível e rápido para a determinação de dexametasona em produtos farmacêuticos e em amostras de urina humana sem qualquer tratamento prévio.The electrochemical behavior of dexamethasone, a steroid hormone, was studied on a multiwalled carbon nanotube (MWCNTs) modified pencil electrode (PE) by square wave voltammety and electrochemical impedance spectroscopy (EIS). Dexamethasone showed one oxidation peak potential around +0.80 V on the surface of the modified electrode. Under optimized conditions, the oxidation peak current depended on the dexamethasone concentration and was linear in the range of 0.15-100 μmol L -1 dexamethasone with a detection limit of 0.09 μmol L -1 dexamethasone. The effects of potential interfering substances on the determination of dexamethasone were investigated to find that the proposed sensor is a sensitive and fast tool for the determination of dexamethasone in both pharmaceutical and human urine samples without any pretreatment.

Direct electrochemical analysis of dexamethasone endocrine disruptor in raw natural waters

“…Moreover, as can be seen in the Experimental section, these samples were collected in areas with a large presence of sediments, detritus rich in organic matter, where its mineralization is associated to environmental conditions, such as redox potential, dissolved oxygen, pH and temperature, 1 indicating the likely presence of humic acids. Studies with natural waters showed that these substances can interact with other dissolved compounds in the environment, 14,29 in this case DMZ molecules, which can reduce their concentration in the electrochemical cell. Recently, Botero et al 7 showed that some drugs can interact with ionized oxygenated groups of aquatic humic substances, through hydrogen bonds, which can strongly influence the transport and reactivity of these contaminants in aquatic systems.…”

“…[13][14][15] Electroanalytical methods can be interesting alternatives for this purpose, due to their sensitivity, selectivity, and relatively short time of analysis in comparison with traditional analytical procedures. [15][16][17][18] Square-wave adsorptive voltammetry (SW-AdsV) is a wellestablished and fast electroanalytical technique and has been applied in the analysis of DMZ in different matrices, such as pharmaceutical preparations and biological fluids.…”

Fast Determination of Ciclopirox in Pharmaceutical Products by Amperometry in Flow and Batch Injection Systems

“…Voltammetric sensors based on carbon electrodes present a wide potential window and low capacitive current. Owing to these characteristics, they have been successfully used in the quantification of different pharmaceutical products 13–17. Moreover, carbon electrodes can be readily coupled with flow system analysis (FIA) or used in association with batch injection analysis (BIA) during amperometric analysis 18–21.…”

A combined liquid three-phase micro-extraction and differential pulse voltammetric method for preconcentration and detection of ultra-trace amounts of buprenorphine using a modified pencil electrode

“…In coupling an electrochemical method with LPME for trace analysis, type and shape of the working electrode affect the voltammetric results [30][31][32]. For this reason, different types and shapes of working electrodes have been tested in voltammetric methods, among which the multiwall carbon nanotubes-modified graphite electrode has proved to be a suitable one [32,33].…”

“…For this reason, different types and shapes of working electrodes have been tested in voltammetric methods, among which the multiwall carbon nanotubes-modified graphite electrode has proved to be a suitable one [32,33]. In this work, multiwall carbon nanotubes (MWCNTs) were used for modifying a pencil graphite electrode to develop a sensitive and useful tool for the determination of buprenorphine.…”