Electrochemical fabrication of poly(l-alanine)-gold nanoparticle nanocomposite-modified electrode: application for determination and mechanism of antipsychotic drug olanzapine

Abstract

This work presents a new electrochemical sensor based on poly(l-alanine) (l-Ala) (as a conducting polymer), and gold nanoparticles (AuNPs) coated with a pre-anodized pencil graphite electrode (pre-PGE). Electrosynthesis, preparation, and sensor characterization were studied by cyclic voltammetry, electrochemical impedance spectroscopy, and energy dispersive X-ray spectroscopy. Electrocatalytic activities of the sensor (AuNPs/poly(l-Ala)/pre-PGE) were compared with pre-PGE, poly(l-Ala)/pre-PGE. This polymer–nanoparticles-modified electrode was evaluated to determine olanzapine (OLA) by differential pulse voltammetry in Britton–Robinson buffer solution. The effect of each nanomaterial and pH was tested to investigate sensor performance. OLA's oxidation peak (0.850 V) was found linearly in the range of 0.271–1000.0 µM with a detection limit of 0.081 μM. The analytical applicability of the sensor was successfully carried out in pharmaceutical dosage forms, human urine, and human serum. Moreover, the electrochemical oxidation mechanism of the antipsychotic drug OLA was studied using cyclic voltammetry to understand its action mechanism and side effect. Graphical Abstract: [Figure not available: see fulltext.].