Development of an Ultra-Sensitive Electrochemical Sensor: AgNPs Deposition on Fe3O4NPs-GO Surface for Accurate Quantification of Morphine and Pethidine in Biological Samples

Due to the limited electrochemical reactivity of morphine (MO) and pethidine (PE), conventional electrodes struggle to detect trace levels of these substances. Consequently, achieving high-performance electrochemical sensors becomes a challenging task. In response to this challenge, we have devised an advanced electrochemical sensor by incorporating silver nanoparticles (AgNPs) onto the surface of a magnetite nanoparticles-graphene oxide nanocomposite (Fe₃O₄NPs–GO) for the purpose of detecting MO and PE. The amalgamation of AgNPs and the Fe₃O₄NPs-GO composite onto the glassy carbon electrode (GCE) exhibited outstanding electrochemical responses. This modification resulted in a notable increase in the oxidation current for MO and PE, rising from 1.5 μA and 13 μA at the bare electrode’s surface to 660 μA and 1690 μA, respectively, at the surface of the final modified electrode. The proposed sensor demonstrated impressive limits of detection (15 nM for MO and 3.1 nM for PE) and broad linear ranges (0.02–140 μM for MO and 0.01–80 μM for PE) for accurately quantifying MO and PE. Additionally, the sensor displayed notable selectivity for detecting MO and PE, even in the presence of various common interfering compounds. The outcomes of analyzing real samples using the MO and PE sensors indicate that the sensor holds promise as a valuable tool for determining both analytes in biological samples.