【作者】 毛勋；

【导师】 黎拒难；

【作者基本信息】 湘潭大学 ， 分析化学， 2004， 硕士

【摘要】 本文利用碳糊电极(CPE)吸附伏安法研究金属离子锆和钒,为钒和非电活性金属元素锆的电化学分析提供了新的途径。 全文共分四章。 第一章利用锆-铬蓝黑R(EBBR)在CPE上产生与EBBR试剂峰很好分开的还原峰,建立了吸附伏安法测定锆的新方法。利用其在-0.29 V(vs.SCE)左右的二次导数峰电流与锆的浓度在一定范围内成线性关系测定锆。最佳测定条件为:0.14 mol/L的HCl溶液,于 0.4 V富集,从 0.4 V至-0.6 V以 300 mV/s的 速 率 线 性 扫 描 。 线 性 范 围 为 9.0×10-9 ～ 9.0×10-8mol/L(4.0 × 10-7 mol/L EBBR,富集 80 s) 和 9.0×10-8 ～1.0×10-6 mol/L(5.0×10-6 mol/L EBBR,富集 30 s),富集 150s,检出限为 5.0×10-9 mol/L(S/N=3)。探讨了该体系伏安峰的性质和电极反应机理。该法用于标准岩石样品中锆的测定,不需萃取分离和掩蔽,直接测定,结果满意。同样发现铪(Ⅳ)在同样的实验条件下于-0.29 V产生一络合吸附波,但是灵敏度远远低于锆,表明该体系可以在痕量铪(Ⅳ)存在下选择性测定痕量锆。 第二章研究了锆-邻苯二酚紫(PV)在CPE正电位区的吸附伏安行为。利用其在 0.85 V(vs.SCE)左右的二次导数峰电流与锆的浓度在一定范围内成线性关系测定锆。最佳测定条件为:0.08 mol/L的HNO3为底液,于 0.4 V富集,从 0.4 V至 1.4 V以 100 mV/s的 速 率 线 性 扫 描 。 线 性 范 围 为 3.0×10-9～5.0×10-8 mol/L(5.6 × 10-7 mol/L PV) 和 1.0×10-8 ～1.0×10-7 mol/L(5.6×10-6 mol/L PV),富集 80 s,检出限为1.0×10-9 mol/L(S/N=3)。探讨了该体系伏安峰的性质和电极反应机理。该法用于标准岩石样品中锆的测定,不需萃取分离和掩蔽,直接测定,结果满意。铪(Ⅳ)在同样的实验条件下也于 0.85 V产生一络合吸附波,灵敏度稍低于锆。 第三章研究了钒-铬蓝黑R在CPE正电位区的吸附伏安行为。利<WP=4>用其在 1.17 V(vs.SCE)左右的阳极二次导数峰电流与钒的浓度在一定范围内成线性关系测定钒。最佳测定条件为:pH4.7 的 0.2 mol/L的HAc-NaAc缓冲溶液,于 0.4 V富集,从0.4 V至 1.4 V以 300 mV/s的速率线性扫描。线性范围为9.0×10-10～6.0×10-8 mol/L(EBBR浓度为 1.2×10-6 mol/L)和 6.0×10-8～6×10-7 mol/L(EBBR浓度为 3.0×10-6 mol/L),富集 450 s,检出限为 4.0×10-10 mol/L(S/N=3)。探讨了该体系伏安峰的性质和电极反应机理。该法用于花生仁和自来水样中钒的测定,结果满意。 第四章研究了钒-荧光镓(LMG)在CPE正电位区的吸附伏安行为。利用其在+0.81 V(vs.SCE)的阳极二次导数峰电流与钒(Ⅴ)的浓度在一定范围内成线性关系测定钒。最佳测定条件为:pH=4.3 的 0.26 mol/L的HAc-NH4Ac缓冲溶液,于+0.4 V富集,从+0.4 V至+1.4 V以 300 mV/s线性扫描。线性范围为4.0×10-9 ～ 1.0×10-7 mol/L (5.0 × 10-7 mol/L LMG) 和1.0×10-7～1.2×10-6 mol/L(2.0×10-6 mol/L LMG),检出限为 1.0×10-9 mol/L(S/N=3)。探讨了该体系伏安峰的性质和电极反应机理。该法用于煤飞灰,粉煤灰和水样中钒的测定,结果满意。更多还原

【Abstract】 The complexes of zirconium and vanadium were investigated byadsorptive voltammetry at a carbon paste electrode (CPE). The newapproaches were provided for determination of vanadium andnon-electroactive metal such as zirconium. The paper consists of four chapters. In the first chapter the adsorptive voltammetry for thedetermination of zirconium is dealed with in the presence oferiochrome blue black R (EBBR) at a CPE. The zirconium(Ⅳ)–EBBR complex can be adsorbed on the surface of theCPE, and produces a peak at –0.29 V (vs. SCE) whenlinear-scanning from 0.4 V to –0.6 V. Optimal analyticalconditions were found to be: 0.14 mol/L HCl, at 0.4Vaccumulation potential for 80 S and at 300 mV/s scan rate. Thelinear range is 9.0×10-9～ 9.0×10-8 mol/L (4.0×10-7 mol/LEBBR) and 9.0×10-8～1.0×10-6 mol/L (5.0×10-6 mol/L EBBR).The detection limit for zirconium (Ⅳ) is as low as 5.0×10-9mol/L (S/N=3) when the accumulation time is 150 seconds.The proposed method has been applied successfully to thedetermination of zirconium in standard samples. Hafniumproduces also an adsorptive wave at –0.29 V under the sameexperiment conditions, but the sensitivity is much lower thanthat of zirconium. It shows that the system could determinateselectively zirconium in the presence of trace amount ofhafnium. In the second chapter a new procedure for determination ofzirconium is presented based on anodic adsorptive stripping of thezirconium (Ⅳ)–Pyrocatechol Violet (PV) complex at a CPE. Thezirconium (Ⅳ)–PV complex can be adsorbed on the surface of theCPE, and produces a peak at 0.85 V (vs. SCE) when linear-scanning<WP=6>from 0.4 V to 1.4 V. Optimal analytical conditions were found to be:0.08 mol/L HCl, at 0.4V accumulation potential for 50 s and at 100mV/s scan rate. The linear range is 3.0×10-9～5.0×10-8 mol/L (5.6×10-7 mol/L PV) and 1.0×10-8～1.0×10-7 mol/L (5.6×10-6 mol/L PV).The detection limit is 1.0×10-9 mol/L (S/N=3) for accumulation 50 s.The proposed method has been applied successfully to thedetermination of zirconium in standard samples of ore withoutextracting and sheltering, with satisfactory results. In the third chapter a new procedure for determination of tracevanadium is presented based on the adsorption voltammetry of thevanadium (V)–EBBR complex at a CPE. The vanadium (V)–EBBRcomplex can be adsorbed on the surface of the CPE and produces aanodic peaks at 1.17 V (vs. SCE), when linear-scanning from 0.4 V to1.4 V. Optimal analytical conditions were found to be: 0.2 mol/LHAc-NaAc (pH4.7), at 0.4 V accummulation for 420s or 120 s and at300 mV/s scan rate. The linear range is 9.0×10-10～6.0×10-8 mol/L(1.2×10-6 mol/L EBBR) and 6.0×10-8～6.0×10-7 mol/L (3.0×10-6mol/L EBBR). The detection limit is as low as 4.0×10-10 mol/L(S/N=3) for accumulation 450 s. The proposed method has beenapplied successfully to the determination of vanadium in peanut andtap water. In the last chapter electrochemical behavior of thevanadium (V)–lumogallion (LMG) complex is devoted to at aCPE. The vanadium (V)–LMG complex can be adsorbed on thesurface of the CPE and produces a anodic peak at 0.81V (vs.SCE) when linear-scanning from 0.4V to 1.4V. Optimalanalytical conditions were found to be: 0.26 mol/L HAc-NH4Ac(pH4.3), for accumulation 120 s at 0.4V and at 300 mV/s scanrate. The linear range is 4.0×10-9～1.0×10-7 mol/L (5.0×10-7mol/L LMG) and 1.0×10-7～1.2×10-6 mol/L (2.0×10-6 mol/L<WP=7>LMG) The detection limit for vanadium(V) is as low as1.0×10-9 mol/L (S/N=3). The proposed method has beenapplied successfully to the determination of vanadium inflying coal-ash, fly-ash and tap water.更多还原