Functionalization of Multi Carbon Nanotubes with 1,2‐Naphthoquinone‐4‐sulfonic Acid Sodium: A Novel Sulphydryl Compounds Sensor Based on Functionalized Carbon Nanotube Film Using Michael Addition

Abstract

AbstractThe functionalized multi‐wall carbon nanotube with 1,2‐naphthoquinone‐4‐sulfonic acid sodium (Nq‐MWNT) was fabricated by a simple and low‐cost method. Techniques of scanning electron microscope (SEM) with energy dispersive X‐ray (EDX) analysis, fourier transform infrared spectroscopy (FT‐IR), ultraviolet visible spectroscopy (UV‐vis) and cyclic voltammetry (CV) were used to characterize the property of the Nq‐MWNT. The results showed that the MWNT with high functionalization of Nq can be obtained using this simple method. The Nq‐MWNT modified carbon paste electrode (Nq‐MWNT/CPE) was fabricated by drop‐casting technique. The resulted modified electrode was tested successfully to detection D‐penicillamine (D‐PA) and captopril (CAP) in an aqueous solution. It is found that D‐PA and CAP participate in Michael addition reaction with Nq on MWNT to form the corresponding thioquinone derivative. The reoxidation of adducts at a potential of less positive than D‐PA and CAP at the surface of the bare CPE leads to an increase in the oxidative current, which is proportional to the concentration of D‐PA and CAP. The catalytic response showed a wide linear range (3‐200 μM and 1‐130 μM for D‐PA and CAP, respectively) as well as its experimental limit of detection can be achieved 0.8 μM, and 0.4 μM for D‐PA and CAP, respectively. The modified electrode for D‐PA and CAP determination is of the property of simple preparation, good stability and high sensitivity. Furthermore, the fabricated electrode was used to determine the content of D‐PA and CAP in the tablet, suggesting the good accuracy of the method.