Electrochemical performance of chitosan oligosaccharide/carbon nanotube composite for detection of trace copper(II) ion

Abstract

Chitosan oligosaccharide (COS)/multi-walled carbon nanotube (MWCNT) composite was prepared by electrostatic self-assembly method. The thickness of COS uniformly enwrapped on the surface of MWCNTs is around 3.3 nm. COS/MWCNT composites exhibit excellent electrochemical property in 1mM [Fe(CN)<inf>6</inf>]^3-/4- solution. The results showed that the composites with 10 wt % MWCNTs presented obvious redox peak and low impedance and have good electrochemical response. The redox peak currents were linear while the concentration of copper sulfate ranging from 2×10^-8 to 2×10^-6 M. The relationship between oxidation peak currents I(A) and Cu²⁺ concentration C (M) is: i<inf>pk</inf> (A) = 2.228 × 10^-6 + 12.96*C (M).