Study On Metallic Complexes Of Schiff Base And Crane Ethane And Apply In Electroanalysis Chemistry

Ion selective electrodes have been widely studied as electrochemistry sensor in recent years. The analytical method of ion-selective electrode is direct and nondestructive, it has simple structure, simple handled, wide potentiometric response range, highly sensitive, it can rapidly determine sample continuously, so it has been applied in most departments of industry and agriculture and science technology. Many metallic complexes of Schiff base and crane ethane are widely used as carrier of ion-selective electrode because of special planar corrdinated. Design, synthesis and application of highly selective and sensitive neutral carriers are main research subjects in the ion-selective electrode studies. This thesis focuses on solvent polymeric membrane (SPM) selective electrodes containing the novel Schiff base and crane ethane as neutral carriers. The electrode can be applied to practice sample analysis.PartⅠof this thesis deals with design of neutral carrier for solvent polymeric membrane thiocyanate electrode with high selectivity.1. A novel solvent polymeric membrane electrode based on salicylaldehyde (o-aminophenol) copper (Ⅱ) ( Cu(Ⅱ)-SHAP) as ionophore is described, which exhibits high selectivity for thiocyanate over many other common anions with an anti-Hofmeister selectivity sequence: SCN^-> ClO₄^->SO₃^2->I^->S₂O₃^2->C₂O₄^2->Sal^->HCO₃^->NO₂^->SO₄^2->F^->Cl^->NO₃^-. The electrode exhibits a near-Nernstian potential linear range of 2.3×10^-6 to 1.0×10^-1 mol/L with a detection limit of 9.0×10^-7 mol/L and a slope of -54.9±1 mV/decade in 0.01 mol/L phosphate buffer solution (pH 4.0, 20℃). We also report a study which compares Cu (Ⅱ)-SHAP with 5-bromide-Cu (Ⅱ)-SHAP.5-bromide-Cu (Ⅱ)-SHAP as carrier had narrow concentration ranging from 5.1×10^-5 to 1.0×10^-1 mol/L and the detection limit was 2.0×10^-5 mol/L and a slope of-63.3 mV/decade (pH 4.0, 20℃). The selectivity behavior of containing Cu(Ⅱ)-SHAP is discussed in terms of the UV-Vispectrum and the process of transfer of thiocyanate across the membrane interface is investigated by use of the AC impedance technique. The electrode is successfully used in the determination of thiocyanate in real samples.2. The complexes of hydroxycitronellal (o-aminobenzoic acid) copper (Ⅱ) (Cu (Ⅱ)-HXAB) and salicylaldehyde (o-aminobenzoic acid) copper (Ⅱ) (Cu (Ⅱ)-SHAB) have been used as anion ionophores in PVC-based membrane ion-selective electrode. The electrode containing Cu (Ⅱ)-HXAB exhibits a near-Nernstian potential linear range of 1.0×10^-6 to 1.0×10^-1 mol/L with a detection limit of 8.5×10^-7 mol/L and a slope of -57.3 mV/decade in 0.01 mol/L phosplate buffer solution (pH 5.0, 20℃). The electrode exhibits high selectivity for thiocyanate over many othercommon anions with an anti-Hofmeister selectivity sequence: SCN^->Sal^->ClO₄^->I^->NO₃^->HCO₃^-> H₂PO₄^->NO₂^->Cl^->F^-. We also report a study which compares Cu (Ⅱ)-HXAB with Cu (Ⅱ)-SHAB. Cu (Ⅱ)-SHAB as carrier had narrow concentration range from 4.0×10^-6 to 1.0×10^-1 mol/L with a detection limit of 2.0×10^-6 mol/L and a slope of -69.4 mV/decade. The selectivity behavior of containing Cu (Ⅱ)-HXAB is discussed in terms of the UV-Vispectrum, the process of transfer of thiocyanate across the membrane interface is investigated by use of the AC impedance technique and IR spectra of the complex is recorded with a Spectrum GXFTIR. The electrode is successfully used in the determination of thiocyanate in real samples.PartⅡof this thesis deals with design of neutral carrier for solvent polymeric membrane Al(Ⅲ)-selective electrode and Cr(Ⅲ)-selective electrode with high selectivity.1. A novel poly (vinyl chloride) (PVC) membrane sensor for Aluminum ion was prepared by employing 1,1,6,6,11,11,16,16-eight methyls-21,22,23,24-four nitrogens mixture alkene as a neutral carrier. The electrode exhibited a near Nernstian response over a wide concentration range from 8.0×10^-5 to 1.0×10^-1 mol/L and the detection limit of the sensor was 4.0×10^-5 mol/L in the pH 3.0. The sensor exhibited a Nernstian slope of 20.0 mV per decade. The response time of the sensor was about 20.0 s. The electrode had been used as an indicator electrode in potentiometric titration of Al(Ⅲ) with EDTA.2. A new selective chrome PVC membrane electrode based on 3-methoxy-4-hydroxybenzaldene-hydrazine-carbothioamide as a neutral carrier is described, which exhibits high selectivity for chrome over many other common cations. The electrode exhibits a near-Nernstian potential linear range of 3.0×10^-5～1.0×10^-1 mol/L with a detection limit of 1.5×10^-5 mol/L and a slope of 20.0 mV/dec in pH=3.0 nitric acid solution. The electrode is successfully used as indicator electrode in the potentiometric titration of chrome ions with EDTA.