All-solid-state composite potentiometric iodide selective electrode and its potentiometric applications

In this thesis, a potentiometric solid-state composite ion selective electrode (ISE) was developed for iodide ion determination. The synthesized mercury(II)-salcilaldehyde thiosemicarbazone complex (1:1) was employed as ionophore material in the electrode structure. For the optimization of the selective composite layer, composite ion selective electrodes with different compositions were prepared using the synthesized complex, graphite, multi-walled carbon nanotube (MWCNT), plasticizer, ionic addive and media providers, and their potentiometric performance characteristics were tested. It was determined that the electrode with the composition of 10 mg Mercury(II)-salcilaldehyde thiosemicarbazone complex, 26 mg dioctylphthalate (DOP) plasticizer, 5 mg MWCNT, 4 mg methyltrioctylammonium chloride (MTOA-Cl) and 65 mg graphite exhibited the best potentiometric performance properties. Linear operating range, slope value, detection limit, pH operating range and response time of the electrode were determined as 1.0×10-5-1.0×10-1 M, 55.2 mV/decade, 9.0 × 10-6 M, 4-8 , and ≈ 60 s, respectively. It has been observed that the electrode exhibits a highly reproducible, stable and selective potentiometric response to iodide ions. The analytical application of the electrode was carried out by using it as an indicator electrode in the titration of iodide ion in synthetic solutions and by using the standard addition method to determine the KI content of a drug used in the treatment of goiter.