基于多壁碳纳米管/壳聚糖多层膜修饰玻碳电极邻苯二酚的测定

改进了碳纳米管在壳聚糖溶液中的分散方法,制备了多壁碳纳米管/壳聚糖多层膜修饰玻碳电极,对比了不同修饰层数膜电极的循环伏安和电化学阻抗行为,5层多壁碳纳米管/壳聚糖膜修饰玻碳电极的电化学性能优良.在最优实验条件下,该修饰玻碳电极对邻苯二酚(CAT)有灵敏的响应,CAT浓度在3.99×10-6～9.09×10-4mol/L范围内与氧化峰电流呈良好的线性关系,检出限为2.39×10-6mol/L(S/N=3).该修饰玻碳电极性能稳定,测定4×10-5mol/LCAT溶液,RSD(n=10)为2.1%;15周后,该电极的响应值仅降低1.9%.     

聚磺基水杨酸/碳纳米管修饰电极在抗坏血酸共存时测定多巴胺

研究了聚磺基水杨酸/多壁碳纳米管修饰玻碳电极的制备及多巴胺在此修饰电极上的电化学行为, 讨论了修饰条件、扫速、溶液 pH 以及抗坏血酸的干扰对多巴胺在这种复合物电极上响应的影响. 在 pH 7.4 磷酸盐缓冲溶液中, 在1.0×10-3 mol/L 抗坏血酸共存的条件下, 多巴胺氧化峰电流与其浓度在 5×10-7～10-4 mol/L 范围内分段呈线性关系, 检出限为 1.0×10-7 mol/L. 结果表明: 聚磺基水杨酸/多壁碳纳米管修饰电极结合了多壁碳纳米管灵敏度高和聚磺基水杨酸选择性好的优点, 可用于抗坏血酸共存条件下多巴胺的测定.     

碳纳米管修饰电极对对苯二酚和邻苯二酚的电催化研究

用循环伏安法(CV)和交流阻抗技术(EIS),研究了对苯二酚(HQ)和邻苯二酚(CC)在多壁碳纳米管(MWCNT)修饰电极上的电化学行为。分析和比较了修饰电极对这两种酚的催化反应。修饰电极对两种多酚类化合物都有强烈的电催化作用,电极过程受扩散控制。在pH 5.8的HAc-NaAc缓冲溶液中,HQ在修饰电极上的线性范围是10×10-4~1.0×10-2mol/L,检出限为1.0×10-5mol/L;在pH 4.4的HAc-NaAc缓冲溶液中,CC在修饰电极上的线性范围是4.0×10-5~2.0×10-3mol/L,检出限为8.0×10-6mol/L。该修饰电极可对HQ和CC同时进行测定。     

氟嗪酸在碳纳米管修饰电极上的电化学行为及含量的测定

在玻碳电极上制备了多壁碳纳米管/Nafion(MWNTs-Nafion)膜,用交流阻抗谱(EIS)、循环伏安法(CV)、线性扫描伏安法(LSV)研究了氟嗪酸在该膜上的电化学行为。与裸玻碳电极相比,这种纳米结构膜修饰的电极对氟嗪酸的电化学氧化显现出极好的促进作用,氟嗪酸的氧化峰电流明显增强,在修饰电极上于 0.97 V处产生了1个灵敏氧化峰。LSV测定氟嗪酸的线性范围为1.0×10-8～1.0×10-6mol/L和1.0×10-6～2.0×10-5mol/L,开路富集400 s后,检出限为8.0×10-9mol/L(3倍信噪比),方法可用于人尿中氟嗪酸的实时测定。     

水合肼在多壁碳纳米管修饰电极上的电化学行为及测定

报道了水合肼在碳纳米管修饰电极上的电化学行为以及水合肼测定的新方法。与裸玻碳电极相比,多壁碳纳米管修饰玻碳电极使水合肼的氧化峰电流显著提高,同时氧化过电位降低,测定灵敏度大为提高。优化了底液、pH、修饰剂量等测定条件。在最佳条件下,该修饰电极测定水合肼的线性范围为2.9×10-8~9.8×10-4mol/L,线性相关系数为-0.9945,检出限为1.0×10-9mol/L。对1.0×10-4mol/L的水合肼平行测定10次的相对标准偏差为4.4%。此方法已用于模拟水样中水合肼的测定。     

碳纳米管-TiO_2修饰电极伏安法测定维生素K_3

利用碳纳米管、二氧化钛两种纳米材料制成碳纳米管-TiO2复合膜修饰电极,进行了维生素K3电化学行为的研究。维生素K3在碳纳米管-TiO2复合膜修饰电极的电化学响应优于碳纳米管修饰电极,表明前者具有更好的催化作用。通过条件实验的优化,结果表明维生素K3在pH=9.42的氨水-NH4Cl底液中,富集时间为10s,富集电位于-0.60V,扫描速度为0.1V/s时有稳定的灵敏的氧化还原峰。峰电流与维生素K3浓度在3.0×10-6～8.0×10-5mol/L范围内呈良好的线性关系,检出限为5.0×10-7 mol/L。考查了修饰电极的重现性,5次平行测量的RSD为1.78%。该方法用于片剂药品中维生素K3含量的测定,回收率在97.5%～102%之间。     

毛细管电泳-修饰电极电化学检测法测定饮用水中溴酸盐

通过静电组装技术在碳圆盘电极（PGE）表面制备{聚二烯丙基二甲基氯化铵（PDDA）/多壁碳纳米管（MWCNT）}n/PDDA多膜,并采用循环伏安法在多膜表面电化学修饰一磷钼酸（PMo12）膜,构筑PGE/{PDDA/MWNTs}5/PDDA/PMo12复合膜修饰电极,研究该复合膜修饰电极电化学及其对溴酸盐（BrO3-）电催化还原性质.在此基础上建立毛细管电泳-PGE/{PDDA/MWNTs}5/PDDA/PMo12修饰电极电化学检法定饮用水中溴酸盐分析新方法.在优化实验条件下,电泳峰面积与溴酸根浓度在5.0×10-8～5.0×10-5mol/L范围内呈良好性关系（r=0.9954）,检出为2.0×10-8mol/L（S/N=3）.     

α-萘胺在多壁碳纳米管-DHP膜修饰电极上的电化学行为及其测定

研究了α-萘胺在多壁碳纳米管-DHP膜修饰电极上的电化学行为,发现多壁碳纳米管-DHP膜能显著提高α-萘胺的氧化峰电流。据此,建立了一种直接测定α-萘胺的高灵敏电分析方法。此方法测定α-萘胺的线性范围为4.5×10-7~2.0×10-5mol/L;开路富集2 min后,其检出限为2.0×10-7mol/L;对浓度为5.0×10-6mol/Lα-萘胺测定的相对标准偏差为5.9%(n=6)。本法已用于长江水样中α-萘胺的测定,回收率为97.5%~104.2%。     

基于多壁碳纳米管化学修饰电极直接测定饮料中的麦芽酚

采用循环伏安法和示差脉冲伏安法研究了麦芽酚在多壁碳纳米管修饰电极上的电化学行为,建立了一种直接测定饮料样品中麦芽酚含量的电分析测试方法. 在pH=8.5的NH3 ·H2 O-NH4 Cl 缓冲溶液中,麦芽酚在多壁碳纳米管修饰电极上于0.55 V(vs.SCE)产生不可逆的氧化峰. 该修饰电极对麦芽酚的电化学反应具有促进作用,阳极峰电流与溶液中麦芽酚的浓度成正比,线性范围为5.0×10-6～9.0×10-4mol/L,检出下限为2.0×10-6mol/L.对含5.0×10-5mol/L的麦芽酚溶液平行测定10次的相对标准偏差(RSD)为1.1%.多壁碳纳米管修饰电极具有良好的电极稳定性,可用于饮料样品中麦芽酚的直接测定,避免了繁复费时的样品前处理过程. 将该修饰电极用于啤酒、可乐和葡萄酒样品中麦芽酚测定,回收率为98%～103%.     

阿奇霉素在多壁碳纳米管修饰电极上的电化学行为及其测定

运用循环伏安法与线性扫描伏安法研究了阿奇霉素在多壁碳纳米管修饰玻碳电极上的电化学行为,建立了一种直接测定阿奇霉素的电化学分析方法。结果表明,与裸玻碳电极相比,多壁碳纳米管修饰电极能显著提高阿奇霉素的氧化峰电流,阿奇霉素的电极过程完全不可逆,存在典型的吸附特性。在优化的实验条件下,氧化峰电流与阿奇霉素浓度在3.0×10-7～2.5×10-5 mol/L和2.5×10-5～5.0×10-4 mol/L范围内呈现良好的线性关系,检出限为1.0×10-7 mol/L。     

用氧化还原聚合物修饰多孔电极

对３种类型Ｎａｆｉｏｎ／Ｏｓ（ｂｐｙ）３Ｃｌ２修饰电极的研究结果表明，单位表观电极面积上中继体载量比为：乙炔黑粉末微电极（Ａ）：Ｔｅｆｌｏｎ粘结的乙炔黑膜电极（Ｂ）：平面玻碳电极（Ｃ）＝１０＾３：１０＾２：１．Ａ比Ｂ及Ｃ更容易在真实表面上形成花天酒地而均匀的修饰层而有利于层内的电荷传递。在Ａ类电极基础上制行的葡萄糖酶电极在１０ｍｍｏｌ／Ｌ葡萄糖溶液中的响应电流密度高达４．６×１０＾－＾４Ａ／ｃｍ＾     

Side effects in measurements of selectivity coefficients of solid state ion selective electrodes

The influence of various factors such as solubility, the oxidation of the membrane, and the contamination of the solution, on the experimental values of the selectivity coefficients of solid state sulphide ion selective electrodes is discussed. A new method for the evaluation of very small selectivity coefficients, based on the addition of reagents forming complexes or insoluble salts with the main ion, is proposed. By means of this method, selectivity coefficients for silver, copper, cadmium and lead ion selective electrodes have been determined, which are in far better agreement with thermodynamic values than those described in the literature.     

Carbon-Filled Polymer Paste Reference Electrodes

Abstract

Inexpensive, disposable, carbon-filled polymer paste reference electrodes are reported. These electrodes are designed for use in conjuction with carbon-filled polymer paste ion-selective probes reported earlier. Attachment of integrated electronics is easily achieved.     

对季鏻与季鉮离子具有电位响应的二元酸酯PVC膜电极

研究发现二元酸酯PVC膜电极对季鏻和季鉮盐均具有能斯特响应。电极的响应机理是由于季鏻、季鉮阳离子的正电中心与电子云密度较大的酯中苯环产生次级力作用所致。     

新型硫醇硫组合电极研制及性能测试

把玻璃参比电极、环状的银-硫化银指示电极、以及铂丝屏蔽电极组合形成新型硫醇硫组合电极,研究了在含有0.2 mol/L硫离子的醇-水-氨介质中,在表面活性剂存在下,以环状银电极为阳极,恒定微电流电沉积的方式制备硫化银敏感层的条件。由此法制得的新型硫醇硫组合电极在Ag 浓度为1.0×10-1~1.0×10-5mol/L范围内斜率为59.0±0.5 mV/pC,测量下限为2.2×10-6mol/L,与同类商品电极相比,响应速度快、记忆效应小、重复性好、电位稳定,易于批量生产,具有较强的适应性和应用价值。     

A surface renewable iridium oxide-glass composite hydrogen ion electrode

A robust and surface renewable iridium oxide-based pH glass composite electrode was prepared by modifying glass matrix with iridium oxide particles. Fine glass powder coated with iridium oxide was prepared by pyrolyzing ammonium hexachloroiridate-coated glass powder under oxygen atmosphere. First the glass powder was molded into a disk, by using a press, then was sintered in high temperature, and was finally fabricated. The electrode showed linear response between pH 1 and 13 with close slopes to the theoretical value, − 59.2 mV/pH. The electrode showed low hysteresis upon sudden changes of pH from 2 to 6, but in extreme conditions, from pH 13 to 1, it showed values near 16 mV. The electrode maintained the pH response for 36 days, without a significant slope drift, in various storage conditions — deionized water, a pH 7 buffer solution, 4 M KCl, and even in the air. Most of the cations and anions, except electrochemically active compounds or ions, did not interfere with the electrodes seriously. The electrode surface can be renewed reproducibly, by a simple grinding process whenever it becomes fouled or deactivated. The electrode matrix was durable and showed extended lifetime although it was ground repeatedly with 2000 grit SiC emery paper for surface renewal.     

Electroanalytical Determination of Vancomycin at a Graphene‐modified Electrode: Comparison of Electrochemical Property between Graphene,Carbon Nanotube,and Carbon Black

Carbon nanotube, graphene and carbon black, as electrode modifiers, were compared and evaluated for the electrochemical determination of vancomycin. Among them, the best results were obtained at the graphene‐modified electrode. Additions of vancomycin using square wave voltammetry at the graphene‐modified electrode showed a linear range from 0.70 μM to 50 μM and a detection limit of 0.20 μM was obtained. To control the correct dose of vancomycin and reduce its side effects, its accurate determination in blood plasma is very important. Therefore, the method was applied for the vancomycin determination in spiked human plasma samples and satisfactory recoveries were observed. The developed method exhibited fast analysis, high sensitivity, good repeatability and freedom from other interfering species.     

双层聚合膜可乐定选择性涂丝电极的研究

报告一种新型双层聚合膜可乐定涂丝电极的研制。通过电化学聚合,在铂丝表面修饰一层具有导电性能的聚苯胺薄膜,外层涂PVC膜(含四苯硼酸-可乐定活性物质)。此种电极既保持了涂丝电极的优点,又具备较好的稳定性和重现性,连续测定8h,电位值漂移0.8mV,线性范围为1×10^-1～8×10^-6mol/L,电极响应斜率56.7mV/decade;用加入稀释法测定了回收率,平均回收率为100.9%,标准偏差为1.3%。