Simultaneous electrochemical detection of levodapa, paracetamol and l-tyrosine based on multi-walled carbon nanotubes.

Herein multi-walled carbon nanotubes (MWCNTs) were processed by ultrasonication and freeze-drying method. The morphology of the processed MWCNTs was examined by scanning electron microscopy. An original electrochemical sensor for the simultaneous detection of levodapa (LD), paracetamol (PA) and l-tyrosine (Tyr) was developed by dropcasting a mixture of processed MWCNTs and Nafion on a glassy carbon electrode. The as-prepared sensor was studied by cyclic voltammetry and differential pulse voltammetry. The peak currents of LD, PA and Tyr significantly increased compared to those obtained at bare glassy carbon electrodes or unprocessed MWCNTs modified electrodes. The peaks of LD, PA and Tyr were well-defined and obviously separated from each other. The linear ranges for detection of LD, PA and Tyr were 2.0-300.0, 2.0-180.0, and 2.0-120.0 μM, with a detection limit of 0.6, 0.5 and 0.8 μM (S/N = 3), respectively. Finally, the sensor was applied to detect LD, PA and Tyr in serum samples, and the results were satisfactory.