Electrochemical determination of melamine with a glassy carbon electrode coated with a multi-wall carbon nanotube/chitosan composite

A simple and rapid electrochemical determination method of melamine with a glassy carbon electrode coated with a multi-wall carbon nanotube/chitosan composite was developed using differential pulse voltammetry. Herein the diameter of multi-wall carbon nanotubes enwrapped with chitosan is about 28 nm and it is larger than that of as-prepared multi-wall carbon nanotubes (a diameter of 20 nm). The results indicated that the redox peak currents of [Fe(CN) ₆] ^3-/4- were linear while the melamine concentration range from 9.9×10-9 to 1.9×10 ^-7 M. The linear coefficient of the redox peak current was 0.998 and the detection limit was 3.0×10 ^-9 M. The proposed method was applied to analyze the content of melamine in Yili milk of China. The calculated concentration of melamine in this experiment was 4.2×10 ^-6 M and the recovery rate was up to 104.8%.