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Study Of Salicylate And Thiocyanate Electrodes Based On Metallic Complexes Of Schiff Base

Posted on:2009-11-19Degree:MasterType:Thesis
Country:ChinaCandidate:L WangFull Text:PDF
GTID:2178360242996811Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
The analytical method of ion-selective electrode is direct and nondestructive, it has simple structure, simple handled, highly sensitive, wide potentiometric response range, it can rapidly determine sample continuously, so it has been applied in most departments of industry and agriculture and science technology. Design, synthsis and application of highly selective and sensitive neutral carriers are main research subjects in the ion-selective electrode studies. Because some schiff bases and schiff bases metal complexes have special planar structure and feasible Louis acidity, the development of ion-selective electrode obtain prodigiouss advancemen. This thesis deals with design of some novel carriers for poly (vinyl chloride) (PVC) membrane ion- electrode with high selectivity to three kinds of Schiff base and their organic-metal complex respectively.PartⅠ: studies of salicylate electrode based on schiff bases metal complexes in solvent polymeric membrane.1.A novel Salicylate-Selective electrode based on 5-bromide o-salicyladehyde-aminophenol complexes of Co(Ⅱ)as ionophore is described, which exhibits high selectivity for salicylate over many other common anionsns with an anti-Hofmeister selectivity sequenc : Sal->ClO4->SCN->I->NO3->HCO3->Br->NO2->SO32->F>Cl->SO42-. The electrode exhibits a near-Nernstian response to the salicylate ion range from 8.0×10-6 to 1.0×10-1 mol/L, wich has a detection limit of 4.0×10-6 mol/L and a slope of-60.3 mV/decade In a phosphate buffer solution of pH 4.0. The response mechanism is discussed in view of AC impedance and UV spectroscopy technique. The electrode is applied to medicine analysis and the result obtained has been satisfactory.2. A novel Salicylate-Selective electrode based on butane-2,3-dione bis(benzoylhydrazide) Zn(Ⅱ) complex as ionophore is described, which exhibits high selectivity for salicylate over many other common anionsns with an anti-Hofmeister selectivity sequenc:Sal-> ClO4->SCN->I-> NO3->NO2-> Br->F->Cl->SO42-.The electrode exhibits a near-Nernstian response to the salicylate ion range from 2.5×10-5 to 1.0×10-1 mol/L, wich has a detection limit of 1.0×10-5 mol/L and a slope of-54.5 mV/decade In a phosphate buffer solution of pH 4.0. The response mechanism is discussed in view of AC impedance technique. The electrode is applied to medicine analysis and the result obtained has been satisfactory.PartⅡ: studies of thiocyanate electrode based on schiff bases metal complexes in solvent polymeric membrane.A new highly selective thiocyanate electrode based on salicylaldehyde glycin copper(Ⅱ) complex [Cu(Ⅱ)-L] as neutral carrier is developed, which displays an anti-Hofmeister selectivity sequence: SCN->Sar>ClO4->I->Br->NO3->NO2->F->Cl->SO32->SO42-. The electyode exhibits a near-Nernstian response to the thiocyanate ion range from 2.5×10-6 to 1.0×10-1 mol/L, which has a detection limit of 1.0×10-6 mol/L and a slope of-56 mV/decade in a phosphate buffer solution of pH 5.0. The response mechanism is discussed in view of AC impedance and UV spectroscopy technique. The electrode can be applied to the recovery of determination successfully. The electrode has the advantages of simplicity, wide working concentration range and low detection limit.
Keywords/Search Tags:Schiff base and their complexes, ion-selective electrode, high selectivity salicylate, thiocyanate
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