A robust electrochemical sensing platform using carbon paste electrode modified with molecularly imprinted microsphere and its application on methyl parathion detection

A highly sensitive electrochemical sensor using a carbon paste electrode (CPE) modified with surface molecularly imprinted polymeric microspheres (SMIPMs) was developed for methyl parathion (MP) detection. Molecular imprinting technique based on distillation precipitation polymerization was applied to prepare SMIPMs and non-surface imprinted microspheres (MIPMs). The polymer properties including morphology, size distribution, BET specific surface area and adsorption performance were investigated and compared carefully. Both MIPMs and SMIPMs were adopted to prepare CPE sensors and their electrochemical behaviors were characterized via cyclic voltammetry and electrochemical impedance spectroscopy. Compared with MIPMs packed sensor, SMIPMs/CPE exhibits a higher sensing response towards MP with linear detection range of 1 × 10⁻¹²–8 × 10⁻⁹ mol L⁻¹ and detection limit of 3.4 × 10⁻¹³ mol L⁻¹ (S/N = 3). Moreover, SMIPMs/CPE exhibits good selectivity and stability in multiple-cycle usage and after long-time storage. Finally, the developed sensor was used to determine MP in real samples including soil and vegetables and only simple pretreatment is needed. The detection results were consistent with those obtained from liquid chromatography. Collectively, this newly developed sensor system shows significant potential for use in a variety of fields like food safety, drug residue determination and environmental monitoring.