Electrochemical Sensor Based On Molecularly Imprinted Polymer For The Detection Of Difenoconazole

Difenoconazole is a low toxicity fungicide. At present,the methods for the determination of difenoconazole in food are mainly based on liquid chromatography, gas chromatography, chromatography tandem mass spectrum and other analytical means.However, these methods have some shortcomings, for example, long test time, expensive equipment, a amount of solvent in the testing process was required. As a result, it is necessary and urgent to establish a rapid and sensitive method for the determination of difenoconazole.In the study, an electrochemical sensor based on gold nanoparticles (AuNPs) and molecular imprinting membrane was developed for the determination of difenoconazole in food. The method was described as the following steps in details: the molecular imprinted membrane was electrodeposited using difenoconazole as the template molecule and p-aminothiophenol as the functional monomer on to the surface of the glassy carbon electrode (GCE) after it had been modified by AuNPs. On one hand, AuNPs can be used as a signal enhancement component to improve the electrical signal of the sensor,and increased the surface area of the electrode to improve the effective imprinting site. On the other hand, the modified molecular imprinted membrane can specifically recognize difenoconazole. The sensor was characterized by scanning electron microscopy (SEM),atomic force microscope (AFM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). And the reproducibility, stability and selectivity of the sensor were also accessed and studied.The results showed that the electrochemical sensor had a good electrochemical response to difenoconazole in the concentration ranged from 2×10-6mol L-1 to 1.4×10-5 mol L-1. Based on the optimized conditions (S/N = 3), the detection limit was 9.49×10-7 mol L-1.In addition, the electrochemical sensor had good selectivity, repeatability and stability.Compared with the results of high performance liquid chromatography (HPLC), the developed sensor was a good agreement. It was successfully applied for the determination of difenoconazole in food (cabbage, apple and peak juice). The results indicated that the electrochemical sensor could provide a new method for the determination of difenoconazole in food.