Multi-walled carbon nanotubes/chitosanpolymer composite modified glassy carbon electrode for sensitive simultaneous determination of levodopa and morphine

Abstract

A modified electrode was constructed by coating of the glassy carbon surface with carbon nanotubes/chitosan (CNTs/CS) and used for sensitive and selective determination of levodopa (L-dopa) and morphine (MO) in a 0.1 M phosphate buffer (pH 7.0). The electrochemical response characteristics of the modified electrode toward L-dopa and MO were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) techniques. Under optimum conditions the sensor provided a linear CA response in the range of 1–360 μM with a detection limit of 0.86 μM for L-dopa, and in the range of 1–240 μM, with a detection limit of 0.65 μM for MO. The designed sensor was used for determination of L-dopa and MO in human serum and urine with satisfactory results.