Electrochemical study of Si/SiO2/Si3N4 structures and gold electrodes functionalised with amide thiacalix[4]arene for the detection of Hg2+ ions in solution
Résumé
A novel electrochemical sensor based on EIS (electrolyte/insulator/semiconductor) and gold electrodes as transducers and immobilized thin films of p-tert-butyl-tetrakis[(diethylamide)methoxy] tetrathiacalix[4]arene (TCA amide) as sensitive elements has been developed for mercuric ion Hg2+ detection in aqueous environment. Sensitive films of TCA amide used to functionalize semiconductors and gold transducers were deposited by spin coating technique. Improvement of the membrane sensitivity towards Hg2+ ions characteristics of such sensors was achieved by the optimisation of the electrical conditions for electrochemical impedance spectroscopy measurements. For Si/SiO2/Si3N4/TCA amide structures, a Nernstian response (30 mV/decade) and good detection limit for Hg2+ ion was obtained which renders them as a promising tool in environmental control. TCA amide gold electrodes have shown good sensitivity and a low detection limit of about 10−7 M. To characterize the chemical composition of the TCA amide thin film ATR-IRTF study was performed.