Sensitive measurement of trace amounts of promethazine hydrochloride at MWCNT-COOH nanostructures modified pencil graphite electrode based on charge transfer complex formation

Abstract

Functionalized multiwalled carbon nanotubes (MWCNT-COOH) pencil graphite electrode has been fabricated to detect trace amounts of promethazine hydrochloride (PMZ). The modified electrode has been applied in Fe^2+/3+ probes, hydroquinone probe and PMZ solutions by cyclic voltammetry and electrochemical impedance spectroscopy. The MWCNT-COOH/PGE shows better response for electrooxidation of PMZ as compared to MWCNT/PGE based on charge transfer complex formation. Two linear dynamic ranges are seen between 0.05 and 275.0 µM with the limit of detection of 5.61 nM in the analysis of PMZ by differential pulse voltammetry. The diffusion coefficient (D, cm² s⁻¹) and the kinetic parameters such as the electron transfer coefficient (α), and the ionic exchanging current density (i_o) for PMZ have also been determined using electrochemical approaches. The modified electrode has been applied to determine PMZ in real sample with satisfactory results.