Sibutramine detection in weight-loss products using a sodium/phosphorus dual-doped carbon nanotubes modified electrode

Abstract

A new electrode material of sodium and phosphorus dual-doped carbon nanotubes (Na/P-CNTs) was produced by a facile hydrothermal reaction. The Na/P-CNTs nanocomposite was used to modify an electrode for an electrochemical sensing system to determine sibutramine in weight-loss products. The nanocomposite was characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and Fourier transform infra-red (FTIR) and Raman spectroscopy. Electrochemical properties of the nanocomposite were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrode modification improved electro-catalytic activity and electron transfer, which contributed to the effective oxidation of sibutramine. The analytical performances of the fabricated electrode were investigated by measuring sibutramine concentrations by adsorptive stripping voltammetry (AdASV). The electrode produced linear ranges from 0.025 to 20 μg mL−1 and 20 to 60 μg mL−1 and a detection limit of 0.010 μg mL−1, and exhibited good repeatability, reproducibility, anti-interference ability, and rapid analysis time (120 s) for sibutramine. The developed sensor was successfully applied to determine sibutramine in weight-loss products, achieving recoveries from 91 ± 3 % to 102 ± 1 %. This Na/P-CNT nanocomposite achieved performances comparable to standard methods and could be adapted to monitor other electroactive species and for other electrochemical applications.