Molecular imprinting polymer electrosensor based on gold nanoparticles for theophylline recognition and determination

An electrochemical sensor for theophylline (ThPh) was prepared by electropolymerizing o-phenyl-enediamine on a glassy carbon electrode in the presence of ThPh via cyclic voltammetry, followed by deposition of gold nanoparticles using a potentiostatic method. The effects of pH, ratio between template molecule and monomer, number of cycles for electropolymerization, and of the solution for extraction were optimized. The current of the electro-active model system hexacyanoferrate(III) and hexacyanoferrate(IV) decreased linearly with successive addition of ThPh in the concentration range between 4.0 x 10(-7)similar to 1.5 x 10(-5) mol.L(-1) and 2.4 x 10(-4)similar to 3.4 x 10(-3) mol.L(-1), with a detection limit of 1.0 x 10(-7) mol.L(-1). The sensor has an excellent recognition capability for ThPh compared to structurally related molecules, can be regenerated and is stable.