Recognition of dimethoate carried by bi-layer electrodeposition of silver nanoparticles and imprinted poly-o-phenylenediamine

Thin film of a molecular imprinted polymer based on electropolymerization method with sensitive and selective binding sites for dimethoate was developed. This film was cast on gold electrode by electrochemical polymerization in solution of o-phenylenediamine and template dimethoate via cyclic voltammetry scans and further deposition of Ag nanoparticles. The surface plasmon resonance and cyclic voltammetric signals were also recorded simultaneously during the electropolymerization, controlling the thickness of the polymer film to be 25 nm. The imprinted film showed high selectivity towards to dimethoate. The recognition between the imprinted sensor and target molecule was observed by measuring the variation amperometric response of the oxidation–reduction probe, K3Fe(CN)6, on electrode. Under the optimal experimental conditions, the peak currents were proportional to the concentrations of dimethoate in two ranges, from 1.0 to 1000 ng mL−1 and from 1.0 to 50 μg mL−1, with the detection limit of 0.5 ng mL−1. Due to the high affinity, selectivity and stability the imprinted sensor provides a simple detection platform for organophosphate compounds.