【作者】 赵川；

【导师】 宋俊峰；

【作者基本信息】 西北大学 ， 分析化学， 2002， 博士

【摘要】 流动注射分析是一种非均匀、非平衡状态下的溶液处理技术，具有分析速度快、在线处理能力好、可与多种检测方法联用、精密度高、节省试样试剂等优点，已经在许多重要领域得到了广泛应用。检测器在很大程度上决定了流动注射分析的灵敏度和选择性。目前应用于流动注射分析的电化学检测方法主要有电位法、安培法和双安培法等。 双安培法灵敏度高、选择性好、仪器简单、信噪比高，在流动注射分析中得到了广泛的应用。但到目前为止，双安培法仅限于氧化态和还原态同时存在的同一物质的可逆电对或准可逆电对体系，以I₂/I的应用为最多。迄今为止，尚未见到将双安培法直接应用于不可逆体系的报道。 本论文中主要开展了以下几方面工作：1．首次提出了偶合两个不可逆电对的流动芒射双安培分析法。介绍了方法基本原理，推导了电流～电位、电流～浓度方程，探讨了方法成立的必要条件及影响因素，给出了具有不同氧化还原电位待测物的双安培体系构建原理，并进行了实验验证。2．通过有较小氧化电位的待测物分别与氧化铂或氧化金不可逆电对构成双安培检测体系，建立了10余种涉及医药、生化、环境、工业等领域的重要化合物的流动注射分析方法，并结合催化作用和小外加电压的优势，获得了较高的灵敏度、选择性和信噪比水平。3．根据不可逆电对双安培体系构建原理，对具有较大氧化还原电位的待测物进行了双安培检测，并以酚类的检测为例，通过偶合酚类化合物的氧化和高锰酸根的还原，建立了流动注射测定环境水中总酚的新方法；4．设计制造了适用于有较小氧化还原电位待测物的薄层式双安培流通池和适用于有较大氧化还原电位待测物的双安培检测流通池。 本论文研究结果丰富了流动注射电化学检测基本方法，并在保持双安培法原有高信噪比、高选择性优势的基础上，大大拓宽了双安培法在流动注射分析中的应用范围，并对进一步开发可用于流动注射、液相色谱、毛细管电泳等流动体系的高性能电化学检测器、传感器具有借鉴意义。 西尤大学搏士学位沦文 扮要 本论文包括三个部分。 第一部分：文献综述 第一章：对流动注射电化学分析方法和技术进行了综述，引用截止2000年相关文献共 153篇。 第二部分：方法原理与基础 第二章：通过偶合两个各自独立的，相反的不可逆电对，提出了应用于不可逆电对体系的流动注射双安培检测新方法，并从理论及实验两方面对方法进行了讨论。推导了方法的电流～电位、电流～浓度方程，探讨了方法成立的必要条件及影响因素。结果表明，两具有相近氧化还原电位的不可逆电对共存是方法成立的必要条件。增大外加电压，可以提高灵敏度、扩大线性范围，但同时伴随着选择性的损夫。文中还讨论了具有不同氧化还原电位待测物的双安培体系的构建方法，并分别以尿酸、苯酚为例讨论了当待测物具有较大氧化还原电位时，双安培检测体系的几种构建途径，并对理论讨论进行了试验验证。 第三部分：方法应用 第三章：基于不可逆电对体系流动注射双安培分析法，设计了新型薄层式双安培检测器，并应用于混合氨基酸和人尿中半肤氨酸的测定。该检测器使用两支相同的经阳极化预处理的铂片电极，结构简单，电极面积与池体积比值高。通过偶合半眺氨酸在一支铂片电极上的催化氧化和氧化铂在另一铂片电极上的还原，构建了双安培检测体系，在外加电压为 10 mV时，回路电流与半脏氨酸浓度在4．oxlo”’－4．0。10”’mol几范围内呈线性关系，万法检狈限为 l．oxlo“’mol几(15Pmo… 8次测定 20x10”‘mol几半眺氨酸，电流值 RSD为 0，6％。 第四章：基于单宁在经阳极化的铂电极上的催化氧化和不可逆电对双安培检测原理，建立了流动注射双安培直接检测茶中单宁的新方法。使用经阳极化处理的双铂电极，通过偶合单宁在一支电极上的氧化和氧化铂在另一支电极上的还原两个不可逆电对，在外加电压为OV 时，单宁的氧化电流与其浓度在l．0x10“－l．oxlo”‘moliL范围内呈线性关系，检出限为 6．oxlo”mol／L （S－2）。连续 42次测定 10xlo”’mow单宁，电流值RSD叫二％。 第五章：基于不可逆电对双安培检测原理，建立了流动注射双安培快速检测环境水中总酚的新方法。该方法使用两支极化铂丝电极，通过偶合一支电极上酚的氧化和另一支电极上 MnO。‘的还原，构建了双安培检测体系，在外加电压为 0 V n 西尤大学搏士学位余文 劣要 时，对污水中总酚进行了检测。本方法无须加入任何反应试剂，在响应种类上， 许多无法用个氨基安替比林法（4AAP）和 3－甲基－2－苯并噬哇琳腺（MBTH）法 检测的酚如硝基酚、氨基酚、甲酚、3个二甲酚等，可以很方便用本文方法检测 出来；在响应灵敏度上，本文方法中各类酚的响应百分比普遍比4．AAP ＆和 MBTH法高，尤其是对于硝基酚类；在更多还原

【Abstract】 Flow injection analysis (FIA) is the modern sample handling technique under heterogeneous and non-equilibrium state. It has been widely accepted in the field of automatic analysis for the advantages of high speed, versatility for on-line treatment and various detection method, high precision, and saving of reagents. The detector is the critical part of any FIA system because it to a large extent decides both selectivity and sensitivity of a particular determination. It has been proved advantageous to combine the FIA with electrochemical detection method. The currently used electrochemical methods are mainly potentiometry, amperometry and biamperometry.Biamperometry, based on principle of so-called dead stop endpoint detection, has been widely used in flow analysis for its simplicity, high sensitivity, high selectivity, and high signal to noise ratio. It has been used for reversible or quasi-reversible couple systems when both the oxidized and reduced forms are present in the flow through cell. However, only few reversible couple systems such as k/F have been used successfully, which prevents the method being more widely used. The biamperometry for irreversible redox couples system has not to date been reported.This dissertation includes the works in the following aspects. 1. Firstly the principle of biamperometry for irreversible redox couple is proposed for flow injection analysis. The method is studied from both theoretical and experimental point of view. The general rules for establishing biamperometric detection system, and the influences of experimental parameters are discussed. 2. By coupling the oxidation of the analytes having mild oxidation potentials with the reduction of platinum oxide or gold oxide to form biamperometric detection schemes, flow injection systems are established for above 10 important compounds related to pharmaceutics, biochemistry, environment, and industry. 3. The method is used for the analytes having high redox potentials. As example, by coupling the oxidation of phenols with the reduction of MnO4-, a new flow injection method for the determination of total phenols in environmental water is proposed. 4. Design and construct a thin-layer biamperometricdetection cell for the analytes having mild oxidation potential and a biamerometric cell for the analytes having high redox potentials.The works in the dissertation enriched the basic electroanalytical method for FIA. With inheritance of the conventional advantages of high selectivity and signal to noise ratio of direct biamperometry, the application scope of the biamperometry in flow injection analysis has been largely extended. The method is instructional in developing high performance electrochemical detectors or sensors for flow systems such as flow injection analysis, liquid chromatography, and capillary electrophoresis.The dissertation consists of three parts.Part I ReviewChapter 1: The achievements on flow injection analysis with electrochemical detection are reviewed particularly with 153 references up to the year of 2000.Part II Principle and fundamentalsChapter 2: Biamperometry for the direct determination of irreversible redox couple in flow system has been proposed based on coupling two independent and irreversible couples. The method is studied both theoretically and experimentally. Equations describing the current-voltage characteristics and the current-concentration relationship are presented. The influence of the applied potential difference (AE) and the half-wave potential difference (AEm) between the two irreversible couples on the method are discussed. It shows that small AEm is favorable to construct biamperometric detection system and to achieve high sensitivity and selectivity. Increasing AE leads to an increase in sensitivity. This is, however, accompanied by a decrease in selectivity and signal to noise ratio. To construct biamperometric detection scheme for irreversible system with large AEm, two approaches, adjusting acidity of supporting electroyte or adding new irreversible更多还原