Electrochemical Study of Si/SiO_2/Si_3N_4 Structures and Gold Electrodes Functionalised with Amide Thiacalix[4]arene for the Detection of Hg~(2+) Ions in Solution

摘要

A novel electrochemical sensor based on EIS (electrolyte/insulator/semiconductor) and gold electrodes as transducers and immobilized thin films of p-terf-butyl-tetrakis[(diethylamide)methoxy] tetrathiacalix[4]arene (TCA amide) as sensitive elements has been developed for mercuric ion Hg~(2+) 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 Hg~(2+) ions characteristics of such sensors was achieved by the optimisation of the electrical conditions for electrochemical impedance spectroscopy measurements. For Si/SiO_2/Si_3N_4/TCA amide structures, a Nernstian response (30mV/decade) and good detection limit for Hg~(2+) 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.