A Reliable Electrochemical Sensor Based on Functionalized Magnetite Nanoparticles for Over‐the‐counter Allergy Medication Abuse Sensing in Biological Fluids

Abstract

AbstractDiphenhydramine (DIPH) has become one of the world‘s most widely abused over‐the‐counter medications. In addition to relieving allergy symptoms, it is also recognized for causing elevated energy and mild euphoric effects. The U.S. Food and Drug Administration (FDA) has recently warned about serious problems at high doses including heart problems, seizures, coma or even death among addicted teenagers. Herein, a simple, cost‐effective, and reliable nanocomposite based electrochemical sensor was designed for DIPH quantification in biological fluids. Introducing the functionalized Fe3O4 nanoparticles (NPs) into the inner‐filling solution and the PVC‐based ion sensing membrane has been employed and compared to the classical potentiometric approach. The nanoparticles were incorporated to endorse in situ cooperative ion‐pairing interaction between the ionophore and DIPH, and to improve the selectivity and detection limit (9.5×10−8 M). Nernstian potentiometric response was achieved for DIPH over the concentration range of 1.0×10−7 to 1.0×10−2 M with a slope of 59.0±0.2 mV/decade. Inherent merits of the proposed sensor include fast response time (6 s), superior stability (60 days) with higher sensitivity and selectivity towards DIPH without interference from co‐formulated drugs and several ions commonly found in biological matrices. The proposed sensor was successfully applied to the potentiometric determination of DIPH in different biological fluids (plasma and human milk) with an average recovery of 99.06±1.95 % and 100.34±1.92 %, respectively. As a consequence, the developed ISE might be the ideal choice for in‐line DIPH measurements in plasma samples to identify overdose ingestion and its related symptoms, as well as for quality‐control laboratories without prior treatments.