Sensitive Voltammetric Detection of Chloroquine Drug by Applying a Boron-Doped Diamond Electrode

Geiser Gabriel Oliveira,Paulo Roberto De Oliveira,Bruno Campos Janegitz,Tiago Almeida Silva,Orlando Fatibello-Filho,Déborah Christine Azzi

doi:10.3390/c6040075

Abstract

In this research, a boron-doped diamond (BDD) electrode has been explored to detect the chloroquine drug. The electrochemical performance of BDD electrode towards the irreversible anodic response of chloroquine was investigated by subjecting this electrode to the cathodic (−0.5 A cm−2 by 180 s, generating a predominantly hydrogen-terminated surface) and anodic (+0.5 A cm−2 by 30 s, oxygen-terminated surface) pretreatments. The cathodically pretreated BDD electrode ensured a better-defined anodic peak and higher current intensity. Thus, by applying the cathodically pretreated BDD electrode and square-wave voltammetry (SWV), the analytical curve was linear from 0.01 to 0.25 µmol L−1 (correlation coefficient of 0.994), with sensitivity and limit of detection of 12.2 µA L µmol−1 and 2.0 nmol−1, respectively. This nanomolar limit of detection is the lowest recorded so far with modified and unmodified electrodes.

Highlights

Chloroquine is a widely used antimalarial drug, and it is part of the World Health Organization (WHO) model list of essential medicines [1]
Morphology of boron-doped diamond (BDD) film growth on p-Si wafer with a B-doping level of 8000 ppm was evaluated by SEM
Chloroquine electroactivity on a BDD electrode was investigated for the first time, whereas an irreversible oxidation reaction was diagnosed

Summary

Introduction

Chloroquine is a widely used antimalarial drug, and it is part of the World Health Organization (WHO) model list of essential medicines [1]. This drug belongs to the class of 4-aminoquinolines and acts as a weak base due to the presence of a base side chain in its molecular structure (Figure 1) [2]. Chloroquine is commercialized as a phosphate salt and reaches the peak plasma concentration 4–12 h after an individual dose [3] It is considered a safe drug, the margin between the therapeutic and toxic dose is narrow, and the common side effects of this drug include nausea, vomiting, diarrhea, and abdominal discomfort [4]. The efficiency is not clear, the use of this drug in treating coronavirus 2019 (COVID-19)

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Conclusion