Fabrication of Chitosan-Multiwall Carbon Nanotube Nanocomposite Containing Ferri/Ferrocyanide: Application for Simultaneous Detection of D-Penicillamine and Tryptophan.

We report a simple and effective strategy for fabrication of the nanocomposite containing chitosan (CS) and multiwall carbon nanotube (MWNT) coated on a glassy carbon electrode (GCE). The characterization of the modified electrode (CS-MWNT/GC) was carried out using scanning electron microscopy (SEM) and UV-vis absorption spectroscopy. The electrochemical behavior of CS-MWNT/GC electrode was investigated and compared with the electrochemical behavior of chitosan modified GC (CS/GC), multiwalled carbon nanotube modified GC (MWNT/GC) and unmodified GC using cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). The chitosan films are electrochemically inactive; similar background charging currents are observed at bare GC. The chitosan films are permeable to anionic Fe(CN)63−/4− (FC) redox couple. Electrochemical parameters, including apparent diffusion coefficient for the Fe(CN)63−/4− redox probe at FC/CS-MWNT/GC electrode is comparable to values reported for cast chitosan films. This modified electrode also showed electrocatalytic effect for the simultaneous determination of D-penicillamine ( D-PA) and tryptophan (Trp). The detection limit of 0.9 μM and 4.0 μM for D-PA and Trp, respectively, makes this nanocomposite very suitable for determination of them with good sensitivity. [ABSTRACT FROM AUTHOR]