【作者】 耿明；

【导师】 朱庆仁；

【作者基本信息】 淮北师范大学 ， 分析化学， 2010， 硕士

【摘要】 摘要:本文对几种双指示剂催化反应体系进行了研究,利用铬或铜离子对双指示剂体系的催化作用,根据催化反应速率与催化剂浓度之间的比例关系,建立了双波长双指示剂催化动力学光度法测定痕量铬和铜的新方法。研究了最佳的试剂用量,最佳的反应介质,最佳的反应时间和温度对反应速率的影响,并绘制工作曲线。主要内容如下:1、研究了用过氧化氢氧化中性红和溴甲酚紫体系测定痕量铜。在pH= 9.65的NH₃-NH₄Cl缓冲介质中,痕量铜能同时催化过氧化氢中性红和溴甲酚紫。通过测定460nm和590nm下吸光度值的变化及其与铜离子浓度的线性关系,建立了双波长、双指示剂催化动力学光度法测定痕量铜的新方法。方法的线性范围0.0060～0.072μg/mL,检出限为8.0×10^-12g/mL。对铜进行11次平行测定的相对标准偏差为2.9%。方法用于面粉和大米中痕量铜的测定,结果令人满意。2、研究了用过氧化氢氧化罗丹明B和苯酚红体系测定痕量铬。在HAc-NaAc缓冲溶液介质中,利用铬（Ⅵ）催化过氧化氢氧化罗丹明B和苯酚红的指示反应,分别在430nm和550nm处测量催化体系和非催化体系的吸光度的变化,建立了双波长双指示剂催化动力学光度法测定痕量铬（Ⅵ）的新方法。其方法的线性范围为0.010～3.30μg/25ml,检出限为:3.2×10^-10g/m。该法简单,灵敏度高,选择性好,可用于水中痕量铬（Ⅵ）的测定。3、研究了用过氧化氢氧化次甲基蓝和罗丹明B体系测定痕量铬。在pH=4.8的HAc-NaAc缓冲溶液介质中,利用痕量铬（VI）催化H₂O₂氧化次甲基蓝和罗丹明B褪色的指示反应,通过测量在555nm和665nm下催化体系和非催化体系吸光度的变化,建立了双波长双指示剂催化动力学光度分析测定痕量铬（VI）的新方法。方法的线性范围为0.025～1.40μg/25mL,检出限为5.2×10^-10g/mL。该法简单、灵敏度高、选择性好,用于废水中痕量铬（VI）的测定,结果满意。4、研究了用过氧化氢氧化亮绿SF和苯酚红体系测定痕量铬。在HAc-NaAc缓冲溶液介质中,利用铬（VI）催化H₂O₂氧化亮绿SF和苯酚红褪色的指示反应及其动力学条件,建立了双波长双指示剂的催化动力学分光光度法测定痕量铬（VI）的新方法。实验表明在432nm和640nm下催化体系和非催化体系吸光度的变化与铬（VI）呈线性关系。在最佳实验条件下测得方法的线性范围为0.008～0.360g/ml,相关系数R为0.99359,检出限为2.6×10^-10 g/mL。本方法简单,体系稳定,灵敏度高,选择性好,用于样品中痕量铬（VI）的测定,结果满意。5、研究了用过氧化氢氧化苯酚红和亚甲基蓝体系测定痕量铬。在pH =4.9的HAc-NaAc缓冲溶液介质中,利用铬（Ⅵ）催化过氧化氢氧化苯酚红和亚甲基蓝褪色的指示反应,建立了用双波长双指示剂催化动力学分光光度法测定痕量铬（Ⅵ）的新方法。通过对催化体系与非催化体系吸光度的测定,确定该体系的最大吸收峰位于434nm和670nm处。在最佳实验条件下,该方法的线性范围为0.008～0.112mg/L,R=0.99231,检出限为2.02×10^-11 g/mL,相对标准偏差3.67%。该方法简单,具有较高的灵敏度和较好的选择性,用于样品中铬（Ⅵ）的测定,结果很理想。实验表明,利用双指示剂催化体系不仅提高了动力学分析方法灵敏度,还提高测定方法的选择性,扩宽了分析方法的范围。更多还原

【Abstract】 Abstract: The catalytic-spectrophotometric methods for the determination of trace chromium or copper with dual-indicator were studied. The methods are based on the catalytic effect of chromium or copper on the oxidation of indicators. In the dual-indicator reaction system, the reaction rate was proportional to concentration of catalysts and the determination sensitivity was better than single-indicator system. The dependence of the indicator reaction rate on the reaction variables including the amounts of reagent, reaction solvent,,reaction time and reaction temperature have been studied. According to these,working curve was designed. The paper’s research contents mainly include:1、A catalytic spectrophotometric method for the determination of trace copper was established. Copper was determined by dual-indicator catalytic spectrophotometric method which was based on the catalytic effect of copper on the oxidation of bromocresol purple and neutral red by hydrogen peroxide in NH₃-NH₄Cl medium at pH 9.65. The absorbance of catalytic system and uncatalytic system were measured at 460 nm and 590 nm. Under the optimum conditions, the linear range of the determination of trace copper was 0.0060⁰.072μg/mL. The detection limit was 8.0×10^-12 g/mL. The relative standard deviation was 2.9% （ n = 11）. The method was applied to the determination of trace copper in flour and rice with satisfactory results.2、A catalytic spectrophotometric method for the determination of trace chromium（Ⅵ） was studied.Chromium was determined by dual-indicator catalytic spectrophotometric method which was based on the chromium（Ⅵ） catalyzed oxidation of rhodamine B and phenol red by hydrogen peroxide in the HAc-NaAc buffer solution. The absorbance of the catalytic and uncatalytic systems were measured at 430nm and 550nm.The linear range of determination was 0.010～3.30μg/25ml. The detection limit was 3.2×10^-10 g/ml.The method is simple and of high sensitivity and good selectivity. It was applied to the determination of chromium in water.3、A new dual-wavelength dual-indicator catalytic kinetic spetrophotometric method for the determination of trace chromium was proposed. It was based on the catalytic effect of chromium（Ⅵ） on the oxidation of methylene blue and rhodamine B by hydrogen peroxide in HAc-NaAc buffer medium at pH 4.8. The absorbance of catalytic system and uncatalytic system were measured at 555 nm and 665 nm. Under the optimum conditions, the linear range of the determination of trace chromium（Ⅵ） was 0.025¹.40μg/25mL. The detection limit was 5.2×10^-10 g/mL. The method is simple, high sensitivity and good selectivity. The method was applied to the determination of trace chromium（Ⅵ） in waste water with satisfactory results.4、This paper establishes a dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace of chromium（VI） on the oxidation of Leather green sf and Phenolsulfonphthalein by hydrogen peroxide in the media HAc-NaAc buffer medium. The absorbance of catalytic system and uncatalytic system were measured at 432nm and 640nm. Under the optimum conditions, , the linear range of the determination of trace chromium（VI） was 0.008⁰.360 g/ml,the correlation coefficient was 0.99359. The detection limit was 0.26278 g/L.The method is simple, stability, high sensitivity and better selectibity for the sample of trace chromium（VI） determination ideal .5、A dual-wavelength dual-indicator catalytic kinetic spetrophotometric method for the determination of trace chromium（VI） was studied . It was based on the catalytic effect of chromium（VI） on the oxidation of phenol red and methylene blue by hydrogen peroxide in HAc-NaAc buffer medium at pH 4.9 . The absorbance of catalytic system and uncatalytic system were measured at 434 nm and 670 nm . Under the optimum conditions , the linear range of the determination of trace chromium（VI） was 0.008～0.112mg/L . The detection limit was 2.02E^-10 g/mL . The method is simple , high sensitivity and good selectivity . The method was applied to the determination of trace chromium（VI） in sample with satisfactory results .The experimental results indicate that the catalytic-kinetic methods of single-indicator suffer from poor selectivity or sensitivity towards some ions. The reaction of dual-indicator system is a new catalytic-kinetic method which could overcome these disadvantages. It also could simplify the process of the simultaneous determination of catalysts and develop the. application scope of kinetics analysis.更多还原