An l-dopa electrochemical sensor based on a graphene doped molecularly imprinted chitosan film

Abstract

A molecularly imprinted polymer (MIP) based sensor for detecting L-dopa was fabricated based on the composite of graphene (GR) and chitosan (CS). The microstructure and composition of the imprinted films characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Raman spectroscopy and electrochemical impedance spectroscopy (EIS) indicated that the modified film of GR-MIPs had been formed successfully. Electrochemical evaluation results showed that the sensor exhibited a satisfactory selectivity for molecular binding with an imprinting factor (IF) of 6.2 and a wide linear range from 0.4 μM to 100 μM with a low detection limit of 0.012 μM. This electrochemical sensor exhibited great promise for accurate determination of L-dopa in pharmaceutical preparations and human blood serum for recoveries ranging from 95.0 to 108.0%. Furthermore, compared to imprinted films without graphene doping, GR-MIPs showed a superior chiral sensing for L-dopa in the presence of D-dopa. The results reveal that the insertion of graphene brought about an enhanced sensitivity for chiral sensing and has the potential for application in chiral recognition.