Development of highly sensitive and selective sensor based on molecular imprinted polydopamine-coated silica nanoparticles for electrochemical determination of sunset yellow

Since synthetic dyes in food samples have the potential to be toxic and pathogenic, their monitoring and evaluation are of particular importance, so it is essential to use methods that are simple and cost-effective for their determination. We have here devised an electrochemical method for the determination of sunset yellow (SY) in food samples. Since the fact that dopamine in the water can be spontaneously polymerized (self-polymerized) in the presence of sunset yellow as a template leads to the fabrication of polydopamine (PDA) imprinted, then by introducing this layer on the silica nanoparticles (SiO 2 ) surfaces with an optimized green one-step synthesis method, SiO 2 @MIP PDA NPs achieved. The synthesized SiO 2 @MIP PDA NPs were identified by Field emission scanning electron microscopy (FE-SEM), High resolution transmission electron microscopy (HRTEM), Atomic force microscopy (AFM), Thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) techniques. Then, using this MIP , we modified a CPE electrode and built a sensor to detect the SY at optimum conditions. The sensor has a sensitive response and high selectivity for the SY compared to other analogs and similar structural molecules. It also has good stability and acceptable reproducibility. The built-in sensor had a linear response range of 4.5 nM to 9.1 µM, and a detection limit of 1.5 nM (S/N = 3). This sensor has been used successfully to diagnose SY in several food samples. The extraordinary behavior of this sensor can be assigned to the imprinted cavities of the effective matrix which matched strongly and non-imprinted PDA electronic barriers to the molecules that are outside.