盐酸氯丙嗪在聚L-苏氨酸/多壁碳纳米管修饰电极上的电化学行为

以玻碳电极为基底成功制备了聚L-苏氨酸poly(L-Threonine)/多壁碳纳米管(MCNTs)修饰电极(p-L-Thr/ MCNTs/GCE).研究了盐酸氯丙嗪在该修饰电极上的电化学行为.该修饰电极对盐酸氯丙嗪具有明显的电催化氧化作用,并对此电极进行显微表征.本研究将此修饰电极用于流动注射不可逆双安培(FL-IB)体系的构建,即利用盐酸氯丙嗪在p-L-Thr/MCNTs/GCE上的氧化和高锰酸钾(KMnO4)在另一支铂电极上的还原构建了双安培检测体系,成功的建立了在外加电压为0 V条件下流动注射双安培法直接测定盐酸氯丙嗪的方法.在0 V外加电压下,在1 mol/L pH6.8的磷酸盐缓冲溶液的载液中,氧化峰峰电流与盐酸氯丙嗪浓度在2.0×10-6mol/L～4.0×10-5 mol/L范围内呈良好的线性关系,其线性回归方程为i (nA)=9.73×107C-50(r=0.9993,n=6),在4.0×10-5mol/L～10-3 mol/L范围内呈线性关系,其线性回归方程为i (nA)=2.33×107C+4×103 (r=0.9984,n=7),方法检出限为4.0×10-7 mol/L (S/N=3).连续测定1.00×10-4mol/L的盐酸氯丙嗪标准溶液20次,电流值RSD为2.44%,进样频率为90样/h.该方法具有较高的选择性和灵敏度.对盐酸氯丙嗪片中的盐酸氯丙嗪的含量的测定,结果比较满意.     

L-半胱氨酸自组装修饰金电极-不可逆双安培测定阿魏酸

在裸金电极上制备了L-半胱氨酸自组装膜金修饰电极(L-Cys/SAM-Au/CME),将自组装膜修饰电极用于不可逆双安培体系,利用阿魏酸在L-Cys/SAM-Au/CME上的氧化和KMnO4在裸金电极上的还原,构建双安培检测新体系,建立了在外加电压为0V条件下,流动注射双安培法直接测定阿魏酸的新方法。在0.05mol/LH2SO4溶液中,该氧化峰峰电流与阿魏酸浓度在5.0×10-7~8.0×10-5mol/L范围内呈线性关系(r=0.9961,n=10),其线性回归方程为i(nA)=4.16×107C 50,在1.0×10-4~1.0×10-3mol/L范围内呈线性关系(r=0.9955,n=5),其线性回归方程为i(nA)=5.6×106C 300,检出限为1.2×10-7mol/L。连续测定2.0×10-5mol/L阿魏酸溶液25次,电流值RSD为1.20%,进样频率为80样/h。该方法具有较宽的线性范围、较高的选择性和灵敏度,样品处理方法简单快速,适于在线分析。对阿魏酸钠盐注射液中阿魏酸的测定结果满意。     

巯基乙酸自组装修饰金电极不可逆双安培法对维生素E的测定

在裸金电极上制备了巯基乙酸(mercaptoacetic acid)自组装膜修饰电极(MA/SAMs-Au/CME),并对电极的表面结构进行了电化学表征.结果表明该修饰电极对维生素E(VE)的电化学氧化具有明显的增敏作用. 该文利用VE在MA/SAMs-Au/CME上的氧化和高锰酸钾(KMnO4)在裸金电极上的还原构建了双安培检测体系,成功地建立了在外加电压为0 V条件下流动注射直接测定VE的方法.VE的氧化峰峰电流与其浓度在8.0×10-6 ～8.0×10-5 mol/L范围内呈线性关系(r=0.995 6, n=6),回归方程为I(nA)= 9.87×107c 10,在1×10-4 ～1×10-3 mol/L范围内呈线性关系(r=0.997 0,n=6),回归方程为I(nA)=1.6×107c 104,方法检出限为4.0×10-7 mol/L. 连续20次测定1.00×10-4 mol/L的VE溶液,电流值RSD为2.28%,进样频率为每小时进40个样品.对维生素E片剂中VE含量的测定结果比较满意.     

聚L-苏氨酸铅笔芯修饰电极对盐酸异丙嗪的电化学行为及测定研究

通过循环伏安法(CV法)在铅笔芯电极上成功地制备了聚L-苏氨酸修饰膜,研究了铅笔芯修饰电极上的最佳聚合条件,并对电极的表面结构进行显微表征.同时,研究了盐酸异丙嗪在该修饰电极上的电化学行为.由盐酸异丙嗪在聚L-苏氨酸修饰电极上的氧化和高锰酸钾在金电极上的还原组成双安培检测体系,建立了在外加电压为0V条件下流动注射双安培法直接测定盐酸异丙嗪的新方法.在pH6.8PBS(磷酸盐缓冲溶液)中,该氧化峰峰电流与盐酸异丙嗪浓度在2.0×10-6～1.5×10-3mol/L范围内呈线性关系(r=0.9979,n=12),线性回归方程为I(nA)=1.97×107c-300,方法检出限为8.5×10-7mol/L(S/N=3).RSD为1.60%(n=20),进样频率为100样/h.     

对乙酰氨基酚在L-半胱氨酸修饰金电极上的不可逆双安培测定

在裸金电极上制备了L-半胱氨酸自组装膜修饰电极(L-Cys/SAM-CME),研究了对乙酰氨基酚(AP)在L-Cys/SAM-CME上的电化学行为,结果发现该修饰电极对AP的氧化具有催化作用,与裸金电极相比,氧化峰电位降低了68mV,峰电流增大了1.2×10-5A。本文探讨自组装膜修饰技术用于构建不可逆双安培法的可行性,利用对AP在L-Cys/SAM-CME上的催化氧化和高锰酸钾在裸金电极上的还原构建双安培检测体系,建立了在外加电压为0V条件下流动注射双安培法直接测定对AP的方法。在0V外加电压下,0.05mol/L硫酸载液中,测得对AP的峰电流与其浓度在2.0×10-7mol/L~2.0×10-4mol/L范围内呈良好的线性关系(r=0.9986,n=13),检出限为9.4×10-8mol/L。连续测定1.00×10-4mol/L的AP溶液20次,电流值RSD为1.90%,进样频率为80样/h。     

聚对氨基苯磺酸修饰玻碳电极不可逆双安培法测定酪氨酸

在玻碳电极上成功地制备了聚对氨基苯磺酸修饰电极(P-p-ABSA/GCE),研究了酪氨酸在该修饰电极上的电化学行为.将此修饰电极用于流动注射不可逆双安培体系的构建,建立了流动注射双安培法直接测定酪氨酸的方法.在0 V外加电压下,在0.005 mol/L硫酸载液中,酪氨酸的氧化峰峰电流与其浓度在2.0×10-6 ～2.0×10-4 mol/L范围内呈良好的线性关系,方法的检出限(S/N=3)为1.0×10-7 mol/L.连续测定1.00×10-5 mol/L的酪氨酸标准溶液,电流值的相对标准偏差(RSD)为1.48%(n=20).该方法具有较高的选择性和灵敏度,应用于测定复方氨基酸注射液中酪氨酸的含量的测定,结果比较满意.     

多壁碳纳米管修饰电极-不可逆双安培法测定双嘧达莫

在玻碳电极上成功地制备了多壁碳纳米管修饰电极(MWCNTs/GCE-CME)。研究了双嘧达莫(DPD)在该修饰电极上的电化学行为。基于表面活性效应,得知十二烷基磺酸钠(SDS)可提高DPD在MWC-NTs/GCE-CME的氧化电流,修饰电极对其具有明显的增敏作用,并对存在的机理作了探讨。在SDS介质存在下,通过DPD在MWCNTs/GCE-CME上的氧化和高锰酸钾在另一电极上的还原构建不可逆双安培检测体系,建立直接测定DPD的新方法。在0.05mol/LH2SO4介质中,DPD氧化峰电流与其浓度在1.5×10-6～1.0×10-3mol/L范围内呈线性关系(r=0.9950,n=16);线性回归方程为i(nA)=2.37×106C-450;方法检出限为8.0×10-7mol/L;电流值RSD为1.8%;进样频率为80样/h。本方法具有较高的选择性和灵敏度,样品处理方法简单快速,适合于实时在线分析。修饰电极易于制作,具有良好的稳定性和重现性及抗干扰性能,对DPD片剂测定结果满意。     

线状纳米金修饰碳纤维超微电极检测芦荟大黄素

该文建立了芦荟大黄素(AE)的电化学检测方法。通过柠檬酸三钠还原氯金酸制备线状纳米金,采用一步恒电位沉积方法将线状纳米金沉积在碳纤维超微电极(CFME)表面,考察了电极修饰前后对AE的电催化性能,得到最佳修饰时间为12 min。结果表明,线状纳米金修饰碳纤维电极(LGN/CFME)的氧化峰电流与AE浓度在2.0×10-6~1.0×10-4 mol/L范围内呈良好线性关系,线性方程为Ip(nA)=0.318 1C(μmol/L)+25.01,r2=0.965 3,检出限(S/N=3)为6.19×10-7 mol/L,说明此方法可用于芦荟汁中AE的定量检测。     

预阳极化碳糊电极同时测定对乙酰氨基酚和多巴胺

采用循环伏安法制备了预阳极化碳糊电极,研究了对乙酰氨基酚和多巴胺在该修饰电极上的电化学行为。结果表明,预阳极化碳糊电极对对乙酰氨基酚和多巴胺的电化学行为具有良好的电催化作用。对乙酰氨基酚和多巴胺的氧化峰电流与其浓度在2.0×10-6～5.0×10-4mol/L的范围内呈良好的线性关系,检出限分别为6.3×10-7mol/L,2.5×10-7mol/L。方法已用于药物样品中对乙酰氨基酚和多巴胺的测定。     

酪氨酸在聚5-磺基水杨酸/多壁碳纳米管修饰电极上的电化学行为及其测定

用不同方法制备了四种修饰电极,酪氨酸在聚5-磺基水杨酸/多壁碳纳米管电极上的电化学响应明显优于裸玻碳电极和其他修饰电极.运用多种电化学方法研究了酪氨酸在电极上的电化学行为,结果表明:酪氨酸在电极上的反应是电子数和质子数均为1的扩散控制的不可逆氧化过程,氧化峰电流与酪氨酸的浓度在9.0×10-6～2.0×10-4mol/L的范围内呈良好的线性关系,IP(A)=-1.61×10-9-2.54×10-4c(mol/L),相关系数R=-0.9950,检出限为6.0×10-6mol/L.平均回收率为99.53％.     

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。     

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。     

双极性电化学的概述及研究进展

作为近年来快速发展的一种便携、阵列、简单的电化学体系,双极性电化学在分析检测、材料制备、物质筛选等领域受到研究者的青睐。简要介绍了双极性电化学的特点,介绍了双极性电极（BPE）体系的2种主要装置：开放性BPE和封闭性BPE。并以开放性BPE体系为例,着重阐述了BPE体系的电化学原理。分别介绍了BPE的极性与驱动电极的关系、BPE体系中的电压及电流的分布,为BPE体系的研究者提供简要的理论基础。此外,还列举了BPE体系在分析检测、材料制备和物质筛选等领域的应用。     

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＾     

Preparation and application of a new glucose sensor based on iodide ion selective electrode

An electrode for glucose has been prepared by using an iodide selective electrode with the glucose oxidase enzyme. The iodide selective electrode used was prepared from 10% TDMAI and PVC according our previous study. The enzyme was immobilized on the iodide electrode by holding it at pH 7 phosphate buffer for 10 min at room temperature. The H₂O₂ formed from the reaction of glucose was determined from the decrease of iodide concentration that was present in the reaction cell. The iodide concentration was followed from the change of potential of iodide selective electrode. The potential change was linear in the 4×10⁻⁴ to 4×10⁻³ M glucose concentration (75-650 mg glucose/100ml blood) range. The slope of the linear portion was about 79 mV per decade change in glucose concentration. Glucose contents of some blood samples were determined with the new electrode and consistency was obtained with a colorimetric method. The effects of pH, iodide concentration, the amount of enzyme immobilized and the operating temperature were studied. No interference of ascorbic acid, uric acid, iron(III) and Cu(II) was observed. Since the iodide electrode used was not an AgI-Ag₂S electrode, there was no interference of common ions such as chloride present in biological fluids. The slope of the electrode did not change for about 65 days when used 3 times a day.     

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.     

Enzyme Electrodes For L-Glutamate Using Chemical Redox Mediators and Enzymatic Substrate Amplification

Abstract

L-glutamate was determined by recycling in a bienzyme system consisting of glutamated dehydrogenase and glutamate pyruvate transaminase. The NADH produced in the dehydrogenase reaction was determined either by direct oxidation at a modified graphite electrode or by reoxidation with oxygen through a N-methylphenazinium ion mediator. The oxygen was determined with an oxygen electrode. The former system resulted in an amplification of 15 and the latter of 60 times.The detection limits became 5-10^?7 and 1-10^?7 M L-glutamate for the respective systems.     

Shorter response times and improved selectivity for potentiometric electrodes

The response times of potentiometric electrodes of the coated-wire variety are shortened by the addition of non-selective charge carriers to the ion-selective membrane. As a charge carrier, ferrocene was effective in decreasing the response time by a factor of 2–3, e.g. from 19 to 6 s. The optimum amount of ferrocene in the polymer film was 1.5% (w/w). As an unexpected benefit, the selectivity of the electrodes containing ferrocene improved by up to two orders of magnitude.     

Development of new potentiometric sensors for the determination of proguanil hydrochloride in serum and urine

Potentiometric electrodes were developed for the rapid determination of proguanil hydrochloride in pure samples, pharmaceutical preparations and spiked serum and urine samples using PVC membrane,screen printed(SPE), coated wired(CWE), carbon paste(CPE) and modified carbon paste(MCPE)electrodes based on the ion-exchanger of proguanil with phosphotungestic acid(Pr-PT) as a chemical modifier. The prepared electrodes showed Nernestian slopes of 59.7, 58.1, 58.5, 58.5 and 57.0 for the PVC,SPE, CWE, CPE and MCPE for the proguanil ions in a wide concentration range of 1.0 * 10~(-5)–1.0 * 10~(-2)mol L~(-1) at 25°C with detection limits of 7.94 * 10~(-6), 1.0 * 10~(-5), 1.0 * 10~(-6), 7.07 * 10~(-6) and 2.5 * 10~(-6) mol L~(-1), respectively. The prepared electrodes exhibited high proguanil selectivity in relation to several inorganic ions and sugars and they could be successfully utilized for its determination in pure solutions, pharmaceutical preparations and serum and urine samples using the direct potentiometry and standard addition methods with very good recovery values.