Electrochemical Detection of 4-Dimethylaminophenol Hydrochloride (DMAP·HCl): Development of a Highly Sensitive Voltammetric Method

Abstract

4-Dimethylaminophenol hydrochloride (DMAP-HCl) is widely recognized as a potent antidote for cyanide poisoning in both animal and human subjects. However, its clinical use is occasionally limited by severe in vivo toxicity, necessitating precise monitoring and quantification. In this study, we report the development of a highly sensitive differential pulse voltammetry (DPV) method employing a gold (Au) electrode modified with silver nanoparticles supported by carbon quantum dots (AgCDs). This modification significantly enhances the electrochemical properties of the gold electrode for the redox reaction of DMAP-HCl. Carbon quantum dots (CDs) were synthesized from pineapple peel juice via a hydrothermal approach and subsequently utilized as both reducing and stabilizing agents for the synthesis of silver nanoparticles (AgNPs). Characterization of the CDs and the AgCDs composite using KMnO4/H2SO4, bromothymol blue (BTB), and Tollens reagents confirmed the presence of alcohol, carboxyl, and carbonyl functional groups on their surface, which are essential for electrochemical activity. Under optimized conditions in a Na₂SO₄ electrolytic solution, the AgCDs/Au electrode demonstrated a linear detection range from 3 ng/mL to 70 ng/mL, with an exceptionally low limit of detection of 0.1 ng/mL. These results highlight the potential of the AgCDs/Au electrode as a robust and sensitive platform for the accurate quantification of DMAP-HCl, offering promising applications in both clinical and environmental monitoring.