Characterization of caffeine-imprinted polypyrrole by a quartz crystal microbalance and electrochemical impedance spectroscopy

By Vilma Ratautaite and Deivis Plausinaitis and Ieva Baleviciute and Lina Mikoliunaite and Almira Ramanaviciene and Arunas Ramanavicius
Published in Sensors and Actuators B: Chemical NULL 2015

Abstract

The synthesis and some properties of polypyrrole layer molecularly-imprinted by caffeine (MIP-Ppy), which was formed on gold covered quartz crystal, were evaluated by quartz crystal microbalance (QCM). Electrochemical polymerization was applied for the formation of this MIP-Ppy. In the study unique home-made flow-through \QCM\ cell was used for the formation of MIP-Ppy and \QCM\ measurements. The main advantages of the applied flow-through cell design were (i) reduced volume of the cell and (ii) the possibility to perform continuous association/dissociation processes. The performed \QCM\ measurement data proved that the \QCM\ sensor modified with MIP-Ppy is more sensitive to caffeine than to the theophylline. Evaluation of association/dissociation kinetics between caffeine-imprinted MIP-Ppy and both xanthine derivatives (caffeine and theophylline) and some parameters of thermodynamics calculated for these interactions demonstrated significant differences, which showed that the MIP-Ppy tends to interact with caffeine more strongly than with theophylline. Electrochemical impedance spectroscopy was applied for the evaluation of MIP-Ppy degradation.

Read Article » Back