Chemically Modified Electrodes For Detection Of Thiourea

Chemically modified electrode(CME) is one of the most active research areas in the field of the electrochemistry and analytical chemistry. It is very widely applied in environmental, biological, pharmaceutical and food analysis. This thesis aims at further application of CMEs in electroanalytical area: different modified electrodes were prepared and used to detect small organic molecule thiourea(TU).Small organic molecules 4-Carboxyphenyl and 4-Hydroxyphenyl were respectively modified on the surface of glassy carbon electrode(GC E) by using the diazonium salt reduction method. The various characterization results showed that the bare GC E was superior to CMEs. But CMEs performance is more stable than the bare GCE. Several thiophene molecules were successfully modified on GCEs by electrochemical deposition and cyclic voltammetry. The results indicate that thiophene derivatives modified GC Es, especially the 3-thiopheneacetic acid(3-TAA) and 3-thiophenemalonic acid(3-TMA) modified ones showed high electrochemical sensitivity and repeatability. Electrospun polyvinyl alcohol(PVA) nanofibers were collected on FTO electrode and then calcined at a high temperature. Then 3-TMA was modified on the surface of the CF/FTO electrode by cyclic voltammetry. The product of 3-TMA nanoparticles and carbon fiber was used to sense thiourea(TU), experimental results showed that 3-TMA nanoparticles and carbon fiber produced enhanced electrochemical signal toward detecting TU.This study results show that the diazonium salt reduction method modified electrodes can be preserved for a long time, but the sensitivity is not well. Thiophene derivatives modified GCEs showed high electrochemical sensitivity and repeatability. Through increases the specific area of carbon nanofibers to improve the sensitivity of electrode.