Adsorptive Cathodic Stripping Voltammetry for Quantification of Alprazolam

Abstract

A simple and highly sensitive electrochemical sensor was developed for adsorptive cathodic stripping voltammetry of alprazolam. Based on an electrochemically pretreated glassy carbon electrode, the sensor demonstrated good adsorption and electrochemical reduction of alprazolam. The morphology of the glassy carbon electrode and the electrochemically pretreated glassy carbon electrode were characterized by scanning electron microscopy/energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The electrochemical behaviors of alprazolam were determined by cyclic voltammetry, and the analytical measurements were studied by adsorptive cathodic stripping voltammetry. Optimized operational conditions included the concentration and deposition time of sulfuric acid in the electrochemical pretreatment, preconcentration potential, and preconcentration time. Under optimal conditions, the developed alprazolam sensor displayed a quantification limit of 0.1 mg L−1, a detection limit of 0.03 mg L−1, a sensitivity of 67 µA mg−1 L cm−2 and two linear ranges: 0.1 to 4 and 4 to 20 mg L−1. Sensor selectivity was excellent, and repeatability (%RSD < 4.24%) and recovery (82.0 ± 0.2 to 109.0 ± 0.3%) were good. The results of determining alprazolam in beverages with the developed system were in good agreement with results from the gas chromatography–mass spectrometric method.

Alprazolam Detection Using an Electrochemical Nanobiosensor Based on AuNUs/Fe-Ni@rGO Nanocomposite

“…Two linear ranges were produced based on the calibration plot of cathodic peak current versus alprazolam concentrations: the first from 4 to 500 μg L −1 and another from 1 to 40 mg L −1 . As expected, any increase in the concentration of alprazolam was associated with a higher surface adsorption rate and thus larger signals [ 21 ]. The nanobiosensor also exhibited a low limit of detection of 1 µg L −1 for detecting alprazolam.…”

“…Due to its high attraction to forming hydrogen bonds, alprazolam formed strong bonds with functional groups in Fe-Ni@rGO after electrochemical pretreatment (ECP), resulting in a lower detection limit [ 21 , 48 , 50 , 51 ]. As shown in Figure 6 , the bare electrode diagram did not show a specific peak while measuring certain amounts of alprazolam (500 µg·mL −1 ); the peak current of ECP nanobiosensor, on the other hand, was significantly higher than that of the non-ECP nanobiosensor.…”

“…Electrochemical sensors are becoming more popular due to their simplicity, high sensitivity, excellent selectivity, low cost, fast response, and ease of operation and sample-preparation methods [ 21 , 22 ]. Glassy carbon electrodes (GCEs) are the most frequently used electrodes for those biosensors due to their wide potential window, low background noise, easy surface modification techniques, and low cost [ 23 , 24 , 25 , 26 ].…”

“…Several studies have been aimed at detecting alprazolam using electrochemical techniques [ 21 , 28 , 29 , 30 ]; the majority of them, however, have failed to achieve the required limits of detection. Some have shown that use of nanomaterials can help accomplish a lower limit of detection and a wider linear range [ 31 ] through increase of surface-area-to-volume ratio, conductivity, and interaction with the target analyte [ 32 ].…”

Highly Sensitive Determination of Tenofovir in Pharmaceutical Formulations and Patients Urine—Comparative Electroanalytical Studies Using Different Sensing Methods

“…Both the mercury and amalgam electrodes operate at negative potentials and are not suitable for electrochemically active compounds oxidation. In the positive potential window, the best choice are solid electrodes such as glassy carbon electrodes (GCEs)—one of the most popular ones currently [ 25 , 26 , 27 ]—as they offer high chemical inertness, fast refreshment procedure, stability, and low costs. Various substances are used to modify GCEs’ surface to improve the catalytic properties, electroactive area, yield of the reaction, or the selectivity of the measurements [ 23 , 28 , 29 , 30 ].…”