Electrochemical sensor of 4-aminobutyric acid based on molecularly imprinted electropolymer

A simple and effective procedure based on a molecularly imprinted polymer (MIP) was developed for preparing a selective 4-aminobutyric acid (4-ABA) sensor. The sensitive layer was prepared by electropolymerization of o-phenylenediamine (o-PD) on a gold electrode in the presence of 4-ABA, which acts as a template. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) measurements were used to monitor the process of electropolymerization. The molecularly imprinted sensor was tested by CV as well as DPV to verify the changes of redox currents of hexacyanoferrate. The concentration of 4-ABA in the range of 0.2–20.0 μmol L−1 can be determined with a detection limit of 0.08 μmol L−1 (defined as S/N = 3) under the optimum conditions. The MIP sensor shows high selectivity, sensitivity and reproducibility. The results from sample analysis indicate that the MIP-4-ABA sensor can be used for quantitative analysis.