Preparation and Application of Semicarbazide Electrochemical Sensor Based on Molecularly Imprinting Technique

A molecularly imprinted electrochemical sensor was prepared by electropolymerization using semicarbazide (SEM) as template molecule and o-phenylenediamine as functional monomer in 0.1 mol/L NaAc-HAc buffer solution (pH 5.2). The performance and surface feature of the proposed imprinted sensor was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and scanning electron microscope. The sensor had a rough and porous surface morphology, and showed good recognition and selectivity to SEM. The sensor performance was optimized by using DPV method in 0.5 mol/L KCl solution with 5 mmol/L K-3 [Fe(CN)(6)] as the electron transport medium. The optimized conditions were that the molar ratio of functional monomer to template molecule was 1:2, the elution liquid was 0.2 mol/L NaOH, and elution and incubation time was 15 and 12 min, respectively. The DPV peak current difference of the sensor had a linear relationship with the concentration of SEM in the range of 3.75 similar to 188 ng/L and the detection limit was 1.5 ng/L (S/N = 3). The prepared imprinted sensor was used to detect SEM in commercially available fresh shrimp muscles as well as shrimp contaminated with drugs with satisfactory results, and the recoveries of SEM were in the range of 80%-97%.