| The environment is facing a severe test since the industry is booming. More and more exhaust gas, wastewater and waste residue are produced in the process of metallurgy and Steelmaking, which contain a great quantity of heavy metal ions, having a deleterious effect on the surface water, groundwater and atmosphere, or even jeopardizing human health and well-being. There are many available methods to detect transfer metal ions, but these sophisticated analytical techniques have some disadvantages including high cost, complex operating, time-consuming, limited detection objects, complicated sample-pretreatment procedures and some needed well-controlled experimental conditions. It is urgent for us to develop a low-cost, eco-friendly, fast, sensitive and accurate method to detect metal ions. While the ion selective electrodes offer such advantages. ISEs have been widely used in the field of environmental monitoring, food, clinical, medicinal and industrial samples. The study on ion selective electrode for rapid, sensitive, and accurate detection of toxic and harmful substances is one of the novel and highly attractive research topics in the field of electrochemistry. Also the emergence of neutral organic complex provides a new approach for developing novel electrodes. The research on design, synthesis and application of highly selective and sensitive neutral carriers are the main research subjects in the studies of ion selective electrode. It is one of the most significant research areas of the potentiometric methods of eletrocanalysis and organic chemistry. This thesis focuses on seeking designing and synthesis of novel neutral complex and using them as carriers in the ion selective electrode. The proposed electrode has been tried to apply for determining the transition metal ions in real samples.The thesis concludes three parts:1. Study on Cr(III) ion elective electrode based on three novel benzo[d]midazobe-2-hydrazids as neutral carriersElectrochemical performance of Cr(III) PVC membrane selective electrode based on(E)-N’-(benzo[d][1,3]dioxole)-1H-benzo[d]midazobe-2-hydrazide(L1),(E)-N’-(4-benzyloxy)benzylidene)-1H-benzo[d]midazobe-2-hydrazide(L2) and(E)-N’-(4-methorybenzylidene)-1H-benzo[d]midazobe-2-hydrazide(L3) as novel neutral ionosphores were studied. Three electrodes exhibited good potentiometric responses for Cr(III) ion over wide range 10-6-10-1 mol/L with slope of 22.90±0.3, 21.92±0.3 and 19.58±0.3 m V/decade, respectively. The detection limits were 4.58×10-7, 4.03×10-7and 8.59×10-7mol/L, respectively. Compared to the electrodes based on L1 and L2, the electrode based on L3 showed Nernstian slope and better potential stability and reproducibility. The electrodes were used as the indicator electrode in titration of Cr3+ ions with EDTA and determination of Cr3+ ions in mixed solution of certain concentration of mixed ions, alloy, tea, tap water with satisfactory results.2. Study on Bi(III) ion elective electrode based on triazole derivant as a carrierThe construction, performance characteristics and application of a new bismuth(III) membrane sensor based on a new ligand 3-(3,4,5-trimethoxybenzyl)-4-amino-5-mercapto-1,2,4-triazole(L4) are reported in this paper. The designed sensor exhibited a wide linear response with a slope of 19.8 m V/decade over the concentration range of 1×10-6-1.0×10-3 M. The potentiometric response is independent on the p H of the solution in the range of 3.0-6.0. The electrode shows a response time of 6s. The proposed electrode can be used for at least four weeks without any considerable divergence in potentials. It exhibits very good selectivity relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions. The proposed electrode could be used as an indicator electrode in potentiometric titration of Bi3+ ions with EDTA as well as in the determination of Bi3+ content in stomach medicine.3. Study on Fe(III) ion elective electrode based on diimine derivant as a carrierA new PVC membrane potentiometric sensor that is highly selective to Fe(III) ions was prepared by using N,N’-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene)(iPr2Ph-DAD)as a suitable carrier. The best performance was observed for the membrane composition including 33.00% PVC, 66.00% DOS and 1.00% ionophore. The electrode displayed a linear potential response over a concentration range from1.0×10-6 to 1.0×10-2 M with a detection limit of 4.47×10-7 M and a good Nernstian slope of 19.9±0.3 m V/decade. The sensor response is p H independent in the range of 2.1–6.0 and has a fast response time of 7s. It also shows very good selectivity to Fe(III) ion over many alkali, alkaline earth, transition, and heavy metal ions. The life time of the electrode was 1 months. It has been observed that the developed sensor satisfactorily works in partially non-aqueous media up to 10%(v/v) content of methanol, ethanol and acetone. The proposed electrode could be used to quantify Fe3+ ion in some different synthetic and real samples with satisfactory results. It can also be used as an indicator electrode in potentiometric titration of Fe3+ ion with EDTA. |
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