Novel Chemical Sensors Based on Some Schiff Base Complexes For Selective Determination of Some Transition Metal Cations and Its Applications in Real Samples

Abstract

These is divided into two parts, the first is concerned with the characterization and applications of some novel electrochemical sensors for the analytical of some different species and the second part is concerned with the preparation and the investigation of some new transition metal complexes with the ligand N(2-acetylthiophene)salicylideneimine HL1(ATS) and L2 (ATDP). The thesis contains two parts Part (I) It is divided into three chapters. Chapter (I) This chapter includes the definition of chemical sensors, general introduction, classification, and the characterization of ion selective electrodes.

Chapter (II) Describes construction, characterizations and applications of novel polymeric membrane sensors for determination of silver ion, based on the use of N(2-acetylthiophene)salicylideneimine HL1(ATS) as the neutral ionophore and DOS as solvent mediator. The proposed sensor exhibits significantly enhanced response towards silver ion, with high selectivity for Ag+ against the most possible interferent, Hg2+. Fast Nernstian responses (slope value of 57.9 mV/decade) for silver ions over the concentration range of (1.0 x 10-8 – 1.0 x 10-1 M) were obtained. The developed sensors were used at pH range (3-11). Applications of the sensor for silver ion determination in photographic solutions and medical X-ray by direct potentiometric measurements are demonstrated. The results obtained are in good agreement with atomic absorption spectroscopy. Chapter (III) Describes two polymeric membrane sensors for the selective determination of thiocyanate ion using manganese(II) Mn(II)-ATS as an ionophore and o-NPOE as the plasticizer used in a PVC matrix and KTpClPB as anionic additives. Fast Nernstian slope of (–57.684 mV/decade) of thiocyanate ions over the concentration range of (1.0 x 10-8 – 1.0 x 10-1 M) have been observed. Good selectivity for thiocyanate ion over various other anions is obtained. The potentiometric response is unaffected by pH variation over the pH range (3.5-6.5). The developed sensors are used for determination of thiocyanate level in biological samples like saliva of cigarette smokers and non-cigaratte smokers. The sensors are also used as indicator electrodes for potentiometric titration of thiocyanate ion with standardized silver nitrate solution.