Pretreated Pencil Graphite Electrode as a Versatile Platform for Easy Measurement of Diclofenac Sodium in a Number of Biological and Pharmaceutical Samples

Abstract

A pretreated pencil graphite electrode (PPGE) as an electrochemical sensor was developed and applied to measure diclofenac sodium (DIC). The effects of both potentiostatic and potentiodynamic strategies in the electrochemical pretreatment and performance of the electrode were studied, and it was concluded that the former offers better analytical sensitivity for electroanalytical purposes. PPGE displayed good electrocatalytic activity in comparison to nonpretreated PGE (NPGE). Differential pulse voltammetry (DPV) was used to determine DIC. Therefore, a calibration graph was plotted between the variation of anodic peak currents and the DIC concentration, which was found to be linear in the range 0.23–12.95 μmol/L with the detection limit (S/N = 3) of 0.12 μmol/L. PPGE was utilized to determine DIC in real samples such as biological and pharmaceutical ones, and the good recovery values obtained demonstrated the high accuracy of the modified electrode.

Electrochemical Behavior and Detection of Diclofenac at a Microporous Si3N4 Membrane Modified Water–1,6-dichlorohexane Interface System

“…The aqueous diffusion coefficient of DCF − was determined to be 5.75 × 10 −6 cm 2 s −1 , which is in agreement with literature value of (5.9 × 10 −6 cm 2 s −1 ) [57] and about double-fold higher than the published value, (2.67 × 10 −6 cm 2 s −1 ) [37] for from the chronoamperometric response via solid-liquid electrode. These results reflect the low value of experimental limiting current of the membrane used as discussed in the previous section.…”

“…Thus, it is essential to develop a fast and sensitive method of DCF detection in biological and pharmaceutical applications. To date, several methods have been harnessed for the determination of DCF, such as liquid chromatography [27,28], gas chromatography [29,30], spectrophotometry [31,32], spectrofluorimetry [33], mass spectrometry [34], colorimetry [35], and voltammetry [36,37] in biological samples. Electrochemical methods have recently attracted more attention due to their fast response, accuracy, lower cost, sensitivity, simplicity, and high dynamic range compared to other methods for environmental, pharmaceutical, and biological applications [38][39][40][41].…”

Recent Developments in Voltammetric Analysis of Pharmaceuticals Using Disposable Pencil Graphite Electrodes

“…The performance parameters (i.e., sensitivity and selectivity) of solid working electrodes can be improved by the modification of their electroactive surface area. The simplest, easiest, and most rapid way to change the structure and morphology of the carbon-based electrode surface, and thus of the PGE, with the use of minimum amounts of non-toxic reagents [80] (usually only a supporting electrolyte is required) is electrochemical pretreatment, which consists of potential cycling or electrochemical anodization [10]. During this process, the electrode surface is cleaned, and new active edge-plane sites are produced along with the generation of oxygen-containing moieties (e.g., carbonyl, carboxyl, and epoxide) [14,62,80,81].…”

“…The simplest, easiest, and most rapid way to change the structure and morphology of the carbon-based electrode surface, and thus of the PGE, with the use of minimum amounts of non-toxic reagents [80] (usually only a supporting electrolyte is required) is electrochemical pretreatment, which consists of potential cycling or electrochemical anodization [10]. During this process, the electrode surface is cleaned, and new active edge-plane sites are produced along with the generation of oxygen-containing moieties (e.g., carbonyl, carboxyl, and epoxide) [14,62,80,81]. These functional groups activate the electrode surface by enhancing its hydrophilic properties [82] and may have an electrocatalytic effect, improving the electron transfer rate for some analytes [83].…”

“…All these observations were supported by experimental results. Thus, scanning electron microscopy (SEM) images emphasized that the non-treated PGE had a smooth surface, whereas the electrochemical pretreated PGE (ET-PGE) presented porosity and an increased surface area [80]. CV investigations pointed out the increase in the ET-PGE effective electroactive surface area in comparison with the PGE (e.g., 0.0170 cm 2 for an HB type PGE and 0.0235 cm 2 for ET-PGE [43], 0.0355 cm 2 for a 2B type PGE and 0.1408 cm 2 for ET-PGE [56], or approximately a threefold increase [80]).…”