A Porphyrin Molecularly Imprinted Biomimetic Electrochemical Sensor Based on Gold Nanoparticles and Carboxyl Graphene Composite for the Highly Efficient Detection of Methyl Parathion

A highly sensitive and selective biomimetic sensor based on zinc porphyrin molecularly imprinted Polymer microspheres (MIPMs), gold nanoparticles (AuNPs) and carboxyl graphene (CG) nanomaterials was successfully developed for direct electrochemical detection of methyl parathion (MP). The novel strategy emphasized the fabrication of a porphyrin zinc-based sensor via attaching MIPMs on AuNPs/CG nanocomposites. MIPMs was prepared by free radical polymerization using MP as the template, Zinc porphyrin as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linking reagent and azobisisobutyronitrile (AIBN) as the initiator. The introduction of AuNPs/CG significantly increased the effective electrode area, and amplified the sensor signal. The modified electrode was characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The parameters of the detection process were also optimized. The biomimetic sensor exhibits a much wider linear dynamic range between 1.0 x 10(-6) mol L-1 and 8.0 x 10(-9) mol L-1 and the limit of detection (LOD) down to 3.16 x 10(-10) mol L-1 based on S/N = 3. The sensor had good reproducibility, stability and selectivity for MP detection. The developed sensor was successfully employed for the detection of MP in real samples.