Measurement of Trace Amounts of Anesthetic Thiopental using Imprinted Sol-Gel on Pencil Graphite Electrode Modified with Carbon Nanotubes as an Electrochemical Sensor

Abstract

In this study, a sensitive electrochemical sensor was developed for the trace determination of thiopental using a sol–gel molecularly imprinted polymer on a pencil graphite electrode modified with functionalized carbon nanotubes. The carbon nanotubes were pretreated using a mixture of nitric and sulfuric acids to enhance surface reactivity. Electrochemical characterization was performed using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The sensor's performance was evaluated based on the oxidation and reduction currents of a redox probe, demonstrating superior recognition ability of the imprinted sol–gel electrode compared to its non-imprinted counterpart. Several experimental parameters, including pH and target molecule concentration, were optimized to achieve maximum response. Under optimal conditions, the sensor exhibited a linear response to thiopental in the concentration range of 0.05–75 μM, with a detection limit as low as 10 nM. The applicability of the sensor was successfully demonstrated through the analysis of thiopental in real biological samples.