Green Composite Sensor for Monitoring Hydroxychloroquine in Different Water Matrix

Abstract

Hydroxychloroquine (HCQ), a derivative of 4-aminoquinolone, is prescribed as an antimalarial prevention drug and to treat diseases such as rheumatoid arthritis, and systemic lupus erythematosus. Recently, Coronavirus (COVID-19) treatment was authorized by national and international medical organizations by chloroquine and hydroxychloroquine in certain hospitalized patients. However, it is considered as an unproven hypothesis for treating COVID-19 which even itself must be investigated. Consequently, the high risk of natural water contamination due to the large production and utilization of HCQ is a key issue to overcome urgently. In fact, in Brazil, the COVID-19 kit (hydroxychloroquine and/or ivermectin) has been indicated as pre-treatment, and consequently, several people have used these drugs, for longer periods, converting them in emerging water pollutants when these are excreted and released to aquatic environments. For this reason, the development of tools for monitoring HCQ concentration in water and the treatment of polluted effluents is needed to minimize its hazardous effects. Then, in this study, an electrochemical measuring device for its environmental application on HCQ control was developed. A raw cork–graphite electrochemical sensor was prepared and a simple differential pulse voltammetric (DPV) method was used for the quantitative determination of HCQ. Results indicated that the electrochemical device exhibited a clear current response, allowing one to quantify the analyte in the 5–65 µM range. The effectiveness of the electrochemical sensor was tested in different water matrices (in synthetic and real) and lower HCQ concentrations were detected. When comparing electrochemical determinations and spectrophotometric measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of this sensor in different environmental applications.

Achieving Electrochemical-Sustainable-Based Solutions for Monitoring and Treating Hydroxychloroquine in Real Water Matrix

“…In a previous work, the use of the cork-graphite composite as electrochemical sensor for quantifying HCQ in real water matrices [14] was demonstrated, confirming HCQ pollution in lagoon water. However, the possibility to integrate technologies as an appropriate water depollution solution to eliminate HCQ from a real water matrix was not proven yet.…”

“…The raw cork granules were reduced in size; a fraction below 150 µm (designated as raw cork powder) was selected for constructing the sensor in this work, according to our previous work [24]. The cork-graphite composite sensor (working electrode) was prepared by mechanical homogenization of raw cork powder and graphite in proportions of 70:30% w/w, using 0.3 mL of paraffin oil as a binder and mixing everything in an agate mortar for about 30 min, as previously reported [14].…”

“…The electrochemical tests were performed using an Autolab PGSTAT302N (Metrohm, Zurich, Switzerland) that was controlled with GPES software (4.0) and consisted of a threeelectrode cell, using Ag/AgCl (3.0 M KCl), Pt wire and a cork-graphite sensor (geometrical area of approximately 0.45 mm 2 , while a real area of 116 mm 2 , which was estimated by procedure in [25]) as the reference, auxiliary and working electrodes, respectively. Differential pulse voltammetry (DPV) parameters were as follows-modulation time: (≥0.002 s), 0.05 s; interval time: (≥0.10 s), 0.5 s; initial potential: 1.0 V; final potential: 1.7 V; step potential: 0.00495 V; modulation amplitude: 0.01995 V; potential scan rate: 100 mV s −1 ; and agitation time: 30 s. The optimized parameters were used for all measurements [14]. All analyses were performed in triplicate.…”

“…All electrochemical analyses were conducted without deaeration, at 25 ± 2 • C. For the identification/determination of HCQ in river water matrices, firstly, the electrochemical sensor's response, in terms of current, was verified by constructing an analytical curve in river water samples. Secondly, the HCQ concentration in HCQ-polluted river water sample was electrochemically treated and the HCQ concentration was determined, at collected electrolysis times, using the standard addition method, where the samples were spiked with a known quantity of a standard solution of HCQ, as it is recommended for diminishing the matrix effect on the currentresponse sensibility [14]. Potentiodynamic measurements (polarization curves and cyclic voltammetry) were also carried out at 25 • C in the conventional cell described above with BDD as working electrode.…”

“…Recent studies have demonstrated that HCQ is present in Brazilian water ecosystems, confirming its high persistence and bioaccumulation in vegetation and groundwater [13]. Therefore, it has motived some investigations to develop sensors for quantifying and monitoring HCQ to determine its potential as contaminant as well as the search for an effective approach to remove this micropollutant from wastewaters before its discharge in water ecosystems [14].…”