Electrochemical determination of l-phenylalanine at polyaniline modified carbon electrode based on β-cyclodextrin incorporated carbon nanotube composite material and imprinted sol–gel film

A sensitive and selective electrochemical sensor based on a polyaniline modified carbon electrode for the determination of l-phenylalanine has been proposed by utilizing β-cyclodextrin (β-CD) incorporated multi-walled carbon nanotube (MWNT) and imprinted sol–gel film. The electrochemical behavior of the sensor towards l-phenylalanine was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometric i–t curve. The surface morphologies of layer-by-layer assembly electrodes were displayed by scanning electron microscope (SEM). The response mechanism of the imprinted sensor for l-phenylalanine was based on the inclusion interaction of β-CD and molecular recognition capacity of the imprinted film for l-phenylalanine. A linear calibration plot was obtained covering the concentration range from 5.0 × 10−7 to 1.0 × 10−4 mol L−1 with a detection limit of 1.0 × 10−9 mol L−1. With excellent sensitivity, selectivity, stability, reproducibility and recovery, the electrochemical imprinted sensor was used to detect l-phenylalanine in blood plasma samples successfully.