硒碳糊电极差分脉冲伏安法测定湖水中Sb~(3+)

以石墨粉、Se粉和石蜡为原料制备了掺杂Se粉的碳糊电极(SeCPE)。以SeCPE为工作电极,通过差分脉冲伏安法(DPV)对溶液中Sb~(3+)进行测定。优化条件如下:硒粉比例20%、HCl浓度0.36mol/L、沉积时间60s、沉积电位-0.45V。结果表明,Sb~(3+)的浓度在1.0×10~(-7)~1.0×10~(-5) mol/L范围内与峰电流呈线性,线性相关系数R=0.9980,计算得检出限为0.3×10~(-7) mol/L。该电极具有良好的重现性、再生性和较高灵敏度。     

土豆组织-碳糊电极的研制及应用

本文研制了土豆组织-碳糊电极,并探讨了电极的性能及实用性。实验表明,该电极可用于伏安法快速检测多巴胺。线性范围为5.3×10~(-8)～9.8×10~(-5)mol/L。检测下限达到1.8×10~(-6)mol/L。电极具有良好的重现性和选择性。响应时间短,使用寿命为20天。     

DNA电化学生物传感器测定水中痕量铅

采用物理涂附法将单链DNA固定到金表面得到ssDNA/Au修饰电极。研究表明,该电极在pH 5,0.2 mol/L NaAc-HAc缓冲底液中,可用于测定水中痕量Pb2 。Pb2 以Pb-DNA络合物的形式吸附在电极上,以示差脉冲伏安法测定Pb2 ,在0.15 V(vsSCE)处有灵敏的氧化峰,其峰电流与Pb2 浓度在5.0×10-8~1.0×10-6mol/L范围内呈良好的线性关系,此法的检测限为2.0×10-8mol/L,该修饰电极的稳定性和抗干扰性都较好。用该电极对饮用水中的Pb进行检测,得到了满意的结果。     

铜氮杂配合物修饰金电极对抗坏血酸的分析测定

本实验制备了一种新型的氮杂铜配合物修饰金电极,该电极可用于抗坏血酸的测定。采用循环伏安法和扫描电化学显微镜技术对电极进行了表征。该修饰电极可催化氧化抗坏血酸,相对于裸电极抗坏血酸在修饰电极上氧化电位移动了250mV,并且氧化电流在抗坏血酸的浓度为5.0×10−7 to 4.0×10−5 mol/L时呈线性关系,检测限为4.8×10-8 mol/L。用此方法测定抗坏血酸与文献报道的测定结果一致,这表明该电极可用作抗坏血酸测定的电化学传感器。     

用碳糊修饰电极测定氨基酸的伏安法研究

用10％氧化铝的修饰碳糊电极研究了测定组氨酸的伏安法。 在0.05 mol/L 丁二酸－硼砂（pH=3.5)底液中在－0.6 V出现一还原峰, 结合2.5次微分技术测定组氨酸, 在3.20 ～130 μmol/L 浓度范围内有良好的线性关系, 相对标准偏差为3.4％, 检出限为0.4 μmol/L。 检测灵敏度比文献报道有较大的提高。 文中还讨论了电极过程。     

应用锑膜修饰电极示差脉冲伏安法同时测定多巴胺和抗坏血酸

应用电化学还原法自制的锑膜修饰玻碳电极(GCE)研究了多巴胺(DA)和抗坏血酸(AA)在此修饰电极上的电化学性质.DA和AA在此修饰电极上的氧化电位依次为0.676 V和0.360 V,两者相差316 mV.此电位差值远大于两者在裸GCE电极上的差值(136 mV).据此,可用锑膜修饰的GCE,用示差脉冲伏安法同时测定DA和AA.测定DA和AA的线性范围分别为6.80×10-7～1.33×10-2,2.60×10-6～1.20×10-3mol·L-1,方法的检出限依次为1.50×10-7,6.70×10-7mol·L-1.应用所提出的方法分析了DA的针剂和AA的片剂样品,所得结果与标示值相符,并测得方法的回收率在97.9%～99.3%之间.     

基于拮抗作用检测除草剂的类囊体膜生物传感器研究

利用除草剂对植物类囊体束缚酶分解过氧化氢的拮抗作用,研制了一种快速检测痕量除草剂的电化学生物传感器.将植物类囊体用聚乙烯醇-苯乙烯吡啶(PVA-SbQ)光敏聚合剂在紫外光诱导下产生大分子网状结构进行包埋,制成生物敏感膜,并固定在铂电极表面.根据加入除草剂时类囊体膜束缚酶分解过氧化氢活性的变化,对除草剂进行测定.在含有1×10^-3mol/LNaCl,5×10^-3mol/LMgCl₂和0.01mol/LH₂O₂的Tris-HCl缓冲溶液(pH=7.4)中,基于测量0.65V处H₂O₂氧化电流的变化,可以对下列浓度的除草剂进行定量检测:百草枯3×10^-9～1.5×10^-7mol/L,敌草龙1×10^-8～3×10^-7mol/L,扑草净4×10^-8～3×10^-6mol/L,阿特拉津1×10^-7～5×10^-6mol/L,莠灭净1×10^-7～5×10^-6mol/L.利用PVA-SbQ光聚合膜固定类囊体,能够使酶的活性在低温下保持数月.     

二茂铁修饰碳糊电极示差脉冲伏安法测定槲皮素

制备了二茂铁修饰碳糊电极,并采用循环伏安法研究了槲皮素在该修饰电极上的电化学行为。研究发现:在pH 6.2磷酸盐缓冲溶液中,修饰电极对槲皮素有良好的电催化作用,得到了一对氧化还原峰,其氧化反应是受吸附控制的两电子、两质子电极过程。并在此基础上提出了一种测定槲皮素的示差脉冲伏安法。试验结果表明:槲皮素的氧化峰电流与其浓度在8×10-4～2×10-6 mol.L-1范围内呈线性关系,检出限(3S/N)为7×10-6 mol.L-1。     

金纳米管阵列修饰玻碳电极用于示差脉冲伏安法测定多巴胺

以聚碳酸酯模板为工作电极,采用电沉积法从氯金酸和高氯酸溶液中制得金纳米管。将沉积了金纳米管的模板固定在玻碳电极表面,用氯仿溶解7min将模板溶解。制得了金纳米管阵列修饰电极,采用循环伏安法和微分示差脉冲伏安法研究了多巴胺在修饰电极上的电化学行为,结果表明:多巴胺在该电极上有一对氧化还原峰,提出了示差脉冲伏安法测定多巴胺的方法。在电位+0.170V处,多巴胺的氧化峰电流与其浓度在4.95×10-7～9.9×10-2 mol.L-1范围内呈线性关系,方法的检出限(3σ)为1.06×10-8 mol.L-1。应用该修饰电极测定人尿样品中多巴胺含量,加标回收率在96.9%～101.4%之间,相对标准偏差(n=5)在3.1%～4.2%之间。     

二茂铁修饰青椒籽碳糊电极测定抗坏血酸

以二茂铁作为电子传递介体,制成Ｆｅ修饰的青椒籽碳糊电极,研究了该电极的性能,用恒电位电流法测定了抗坏血酸的浓度并用于药物中抗坏血酸的含量分析,结果与药典法相符。     

Voltammetric Determination of Selected Aminoquinolines Using Carbon Paste Electrode

Optimum conditions have been found for voltammetric determination of mutagenic 5‐aminoquinoline, 6‐aminoquinoline and 3‐aminoquinoline by differential pulse voltammetry and adsorptive stripping differential pulse voltammetry on carbon paste electrode. The lowest limits of determination were found for adsorptive stripping differential pulse voltammetry in 0.1 mol dm^?3 H₃PO₄ (5×10^?7 mol dm^?3 , 1×10^?7 mol dm^?3, and 1×10^?7 mol dm^?3 for 5‐aminoquinoline, 6‐aminoquinoline and 3‐aminoquinoline, respectively). The possibility to determine mixtures of 8‐aminoquinoline with 3‐aminoquinoline or 5‐aminoquinoline or 6‐aminoquinoline, and mixtures of 5‐aminoquinoline with 3‐aminoquinoline or 6‐aminoquinoline by differential pulse voltammetry was verified. Binary mixtures of 8‐aminoquinoline with 3‐aminoquinoline or 6‐aminoquinoline, and of 3‐aminoquinoline with 5‐aminoquinoline could be successfully analyzed.     

Electrochemical Analysis of D‐Penicillamine Using a Carbon Paste Electrode Modified with Ferrocene Carboxylic Acid

The electrochemical behavior of D ‐penicillamine (D ‐PA) studied at the surface of ferrocene carboxylic acid modified carbon paste electrode (FCAMCPE) in aqueous media using cyclic voltammetry and double step potential chronoamperometry. It has been found that under optimum condition (pH 7.00), the oxidation of D ‐PA at surface of such an electrode is occurred about 420 mV less positive than that an unmodified carbon paste electrode (CPE). The catalytic oxidation peak current was linearly dependent on the D ‐PA concentration and a linear calibration curve was obtained in the ranges 7.5×10^?5 M – 1.0×10^?3 M and 6.5×10^?6 M?1.0×10^?4 M of D ‐PA with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods respectively. The detection limits (3σ) were determined as 6.04×10^?5 M and 6.15×10^?6 M. This method was also used for the determination of D ‐PA in pharmaceutical preparation (capsules) by standard addition method.     

聚吡咯碳糊电极的研制及应用

研制了聚吡咯电极，探讨了该电极的性能和实用性，实验结果表明，该电极可用于伏安法快速测定Ｌ－抗坏血酸，在０．１ｍｏｌ／ＬＫＮＯ３底液中，线性范围为１．０×１０＾－１１～９．０×１０＾－９ｍｏｌ／Ｌ检测限为５．０×１０＾－１２ｍｏｌ／Ｌ，电极具有具有良好的重现性和高选择性，响应迅速，使用寿命３个月以上。     

Green and Straightforward Modification of Graphite Electrode via In Situ Synthesis of Graphene Nanosheets for Quantifying Prazosin Hydrochloride in Urine Samples and Pharmaceutical Formulations

A sensitive electrochemical sensor based on in situ modification of graphite electrode via graphene nanosheets (GNs) was developed as a green method for prazosin hydrochloride (PRA) analyses. In this study, GNs were electrochemically synthesized on the surface of graphite electrode via in situ approach and used for the analyses. The proposed sensor showed several advantages such as high sensitivity, low LOD, and excellent repeatability. The oxidation peak current at the optimum analytical conditions using a GNs/graphite electrode at pH 6.0 was linearly dependent on PRA concentration in the range of 0.09–100 µM. A LOD of 0.02 µM and RSD of 3.8 % for 10 µM solution of PRA with a great recovery were obtained.     

Voltammetric Determination of Trace Antiepileptic Gabapentin with a Silver‐Nanoparticle Modified Multiwalled Carbon Nanotube Paste Electrode

For the first time, a novel carbon nanotube bed electrode impregnated with silver–nanoparticles (AgNPs) for the determination of trace amounts of gabapentin (GBP) is described. We synthesized the AgNPs via a new procedure. The voltammetric behavior of the electrode was investigated by cyclic voltammetry. There were linear relationships in the ranges from 3.1×10^?9 to 2.9×10^?2 M and from 1.0×10^?8 to 1.0×10^?2 GBP with square wave and differential pulse voltammetric peak currents, respectively. The detection limits were 5.6×10^?10 and 9.7×10^?9 M, respectively. The electrode showed excellent response over a period of 2 months and was successfully applied in human plasma and pharmaceutical capsular products.     

Utilization of Carbon Paste Electrodes for the Voltammetric Determination of Chlortoluron

Conventional (CPE) and miniaturized (m‐CPE) carbon paste electrodes consisting of a carbon paste filled capillary were used for differential pulse voltammetric determination of chlortoluron in samples of river water and soil, in the latter case after the extraction by methanol. Britton‐Robinson buffer pH 3 with low content of methanol was found to be optimal for the determination. The achieved determination limits were 2.8 µmol L^?1 and 0.34 µmol L^?1 in river water, and 3.1 and 4.3 µg g^?1 in soil, using CPE and m‐CPE, respectively.     

Voltammetric determination of salicylic acid in pharmaceuticals formulations of acetylsalicylic acid

The electrochemical oxidation of salicylic acid (SA) has been studied on a glassy carbon electrode using cyclic voltammetry and differential pulse voltammetric (DPV) method. SA gives a single irreversible oxidation wave over the wide pH range studied. The irreversibility of the electrode process was verified by different criteria. The mechanism of oxidation is discussed. Using differential pulse voltammetry, SA yielded a well-defined voltammetric response in Britton-Robinson buffer solution, pH 2.37 at 1.088 V (versus Ag/AgCl). The method was linear over the SA concentration range: 1-60 μg ml⁻¹. The method was successfully applied for the analysis of SA as a hydrolysis product, in solid pharmaceutical formulations containing acetylsalicylic acid (ASA).     

Application of Novel Zn‐Ferrite Modified Glassy Carbon Paste Electrode as a Sensor for Determination of Cd(II) in Waste Water

This paper describes the preparation of a new sensor based on Zn‐ferrite modified glassy carbon paste electrode and its electrochemical application for the determination of trace Cd(II) ions in waste waters using differential pulse anodic stripping voltammetry (DPASV). Different Zn/Ni ferrite nanoparticles were synthesized and characterized using scanning electron microscopy (SEM) and X‐ray powder diffraction (XRPD). The prepared ferrite nanoparticles were used for the preparation of Zn‐ferrite‐modified glassy carbon paste electrode (ZnMGCPE) for determination of Cd(II) at nanomolar levels in waste water at pH 5. The different parameters such as conditions of preparation, Zn²⁺/Ni²⁺/Fe²⁺ ratio and electrochemical parameters, percentage of modifier, accumulation time, pH and accumulation potential were investigated. Besides, interference measurements were also evaluated under optimized parameters. The best voltammetric response was observed for ZnFe₂O₄ modifier, when the percentage of modifier was 3 %, accumulation time 9 min, pH of supporting electrolyte 5 and accumulation potential ?1.05 V. Thus prepared electrode displays excellent response to Cd(II) with a detection limit of 0.38 ppb, and selective detection toward Cd(II) was achieved.