秋兰姆衍生物作中性载体的铜离子敏感电极

合成了二硫化二（Ｎ，Ｎ－１，４－亚丁基）秋兰姆，以此为载体，制备了ＰＶＣ膜铜离子敏感电极。结果表明，电极对铜离子具有好的选择性和灵敏度。线性范围为８．０×１０＾－＾７－１．０×１０＾－＾２ｍｏｌ／Ｌ。实验发现有选定的底液条件下此电极对蛋白质蛮具有较好的响应，线性范围为１２．５－２００ｍｇ／Ｌ。讨论了电极有关性能。     

聚2-吡啶甲酸修饰电极伏安法测定多巴胺

用循环伏安法制备了聚２－吡啶甲酸修饰玻碳电极，研究了神经递质多巴胺（ＤＡ）在该聚合物薄膜修饰电极上的电化学行为。实验结果表明，在ｐＨ７．０的磷酸盐缓冲溶液中，ＤＡ在该电极上的线性范围为１．０×１０－７～１．０×１０－５ｍｏｌ／Ｌ。该修饰电极对抗坏血酸（ＡＡ）无响应，从而可有效消除其对ＤＡ测定的干扰。     

阿托品选择电极的研制和应用

报道了一种阿托品选择性电极的研制和应用，该电极是将对阿托品敏感的聚氯乙烯膜涂敷于ｐＨ玻璃电极球部表面而制成。在０．１０ｍｏｌ／Ｌ，磷酸盐冲浓度（ｐＨ４．０）中，所制电极对阿托品的Ｎｅｒｎｓｔ响应线性范围为１．７０×１０＾－５～２．００×１０＾－２ｍｏｌ／Ｌ阿托品，响应斜率为５５．８ｍＶ，电极响应时间小于４５ｓ，使用寿命大于６个月，而且具有制作简单，使用方便的特点，已将该电极应用于硫酸阿托品制剂中测     

掺杂磷钼酸根离子聚吡咯膜电极对磷钼酸根离子电位响应的研究

用循环伏安法研究了制备掺杂磷钼根离子聚吡咯化学修饰电极的条件，对其性能进行了电化学表征，电极对磷钼酸根（ＰＭｏ１２Ｏ＾３－４０）离子具有选择性电位响应，线性范围为１．０×１０＾－６～１．０×１０＾－３ｍｏｌ／Ｌ。斜率约为５０ｍＶ，测定了电极的有关性能参数。电极可用于无机磷含量的检测。     

校正计算—催化动力学方法同时测定钨（Ⅵ）和钼（Ⅵ）

利用某些试剂（柠檬酸、酒石酸、草酸及丙二酸）对钨（Ⅵ）、钼（Ⅵ）催化作用抑制程度的差异，对钨（Ⅵ）、钼（Ⅵ）进行了同时测定。先对一组标准钨（Ⅵ）、钼（Ⅵ）混合溶液进行校正计算并建立了线性和非线性的两种模型，再对含量在０．０１２～０．２０μｇ／ｍＬ范围内的未知钨（Ⅵ）、钼（Ⅵ）含量的混合溶液进行了浓度预报。以碘离子选择电极量测催化反应过程中体系的电位变化，并以此值表示催化反应的速率。     

壳聚糖修饰电极开路富集测定工业废水中铅

通过共价键合的方式，制成壳聚糖修饰电极，建立了在非电解条件下，壳聚糖修饰电极络合富集测定Ｐｂ（Ⅱ）的方法，同时对壳聚糖修饰电极的作用机理进行了探讨。Ｐｂ（Ⅱ）的线性范围为０．５０￣２００μｇ·ｍｌ＾－１，相对标准偏差为７．９％，定量下限为０．５０μｇ·ｍｌ＾－１，方法的回收率为９４％￣１０５％。     

以不对称长链叔胺为中性载体的PVC膜PH电极的研究

合成了一系列不对称长链叔胺类化合物作中性载体，研制成ＰＶＣ膜ｐＨ电极。其中（２－羟基苄基）二正癸胺、（β－氰乙基）ＬＡ－２、（２－羟基苄基）ＬＡ－２的电极线性范围分别为ｐＨ２．５～１２．５、ｐＨ２．５～１２．５、ｐＨ３．０～１２．５，斜率分别为５６．６±０．４ｍＶ／ｐＨ、５６．３±０．７ｍＶ／ｐＨ、５５．９±０．３ｍＶ／ｐＨ（３０℃）。这些ｐＨ电极内阻低，响应速度快，性能较稳定，可用于血清样中的ｐＨ值测量。此外，以（２－羟基辛基）ＬＡ－２为载体可制成流通式ＰＶＣ膜ｐＨ内电极型氨气敏电极。     

微分吸附计时电位法测定痛力克

非成瘾性高效镇痛新药痛力克在硫酸底液中产生一灵敏的微分吸附计时电位溶出峰，峰电位在－１．０Ｖ。利用该峰测定痛力克的线性范围为０．０２－２．０ｍｇ／Ｌ，检测限为０．００４ｍｇ／Ｌ。用线性扫描，循环伏安等方法研究了该体系的电化学行为和电极反应机理，认为所研究体系属于有吸附性的不可逆还原过程，电极反应的电子转移数为２，参与电极反应的质子数为２。用该方法测定了片剂中痛力克的含量，结果满意。     

新型安培检测毛细管电泳微系统

将电极、６ｃｍ分离毛细管、缓冲池、检测池集成于８．４×５．０ｃｍ有机玻璃片上,制作了一个毛细管电泳微系统。以碳纤维微盘电极作为工作电极,采用三电极体系柱端检测了１×１０－４ｍｏｌ／Ｌ多巴胺（ＤＡ）,具有良好的重现性,检测限３．６×１０－８ ｍｏｌ／Ｌ,线性范围５×１０－７～１×１０－４ｍｏｌ／Ｌ,并在该系统上分离了邻苯二酚（ＣＡ）和多巴胺的混合物。     

聚苯胺薄膜电极上循环伏安法可逆波理论和验证

提出了聚苯胺薄膜电极上循环伏安法可逆波方程式，对伏安曲线的性质进行了详细的讨论。聚苯胺薄膜电极是利用浓度为１．０９ｍｏｌ／Ｌ苯胺溶液（内含２．０ｍｏｌ／Ｌ ＨＣｌ）在铂电极上用恒电流（０．０１－０．１ｍＡ／ｃｍ＾２）使苯胺发生氧化反应进而经聚合获得。结果表明，该法得到的聚苯胺膜具有良好的均匀度和单一性。在１０ｍｏｌ／Ｌ ＨＣｌ底液中获得的循环伏安曲线与理论结果相符合。     

Micro-Enzyme Electrode Prepared on Platinized Platinum

Abstract

Micro-enzyme electrode with high performance was fabricated on a micro-platinum electrode surface (diameter = 50 ～ 200 μm) by taking advantage of very huge surface of platinized platinum. Glucose oxidase was incorporated into the micropores of platinum particle by immersing a micro-platinized platinum electrode in a solution containing glucose oxidase. The micro-enzyme electrode for glucose demonstrated high performance such as high sensitivity (the least detectable limit : 5 × 10^?7 M), fast responsiveness (100 % response : 3 sec), and accuracy (C.V. = 1.4 %) in the repeated determination of glucose.     

Evaluation of different mediator-modified screen-printed electrodes used in a flow system as amperometric sensors for NADH

This work presents a comparative study between two different methods for the preparation of mediator-modified screen-printed electrodes, to be used as detectors in a reliable flow injection system for the determination of the nicotinamide adenine dinucleotide (NADH) coenzyme. The best strategy was selected for the final development of compact biosensors based on dehydrogenase enzymes. For the first immobilisation strategy, different redox mediators were electropolymerised onto the SPE surface. The second immobilisation strategy was carried out using polysulfone–graphite composites, which were deposited by screen-printing technology onto the screen-printed electrode (SPE) surface. Both methods achieved an effective and reliable incorporation of redox mediators to the SPE configuration. Finally, a flow system for ammonium determination was developed using a glutamate dehydrogenase (GlDH)-Meldola's Blue (MB)-polysulfone-composite film-based biosensor.

The stability of the redox mediators inside the composite films as well as the negligible fouling effect observed on the electrode surface improve the repeatability and reproducibility of the sensors, important features for continuous analysis in flow systems. Furthermore, the optimised bio/sensors, incorporated in a flow injection system, showed good sensitivities and short response times. Such a good analytical performance together with the simple and fast sensor construction are interesting characteristics to consider the polysulfone-composite films as attractive electrochemical transducer materials for the development of new dehydrogenase-based SPEs.     

Pulse Voltammetric Biosensing System for the Rapid Determination of Glucose With Micro-Enzyme Sensor

Abstract

An electrochemically prepared micro-enzyme electrode whose diameter is 50 jim is combined with an Pt auxiliary electrode and a reference electrode to assemble a three electrode device for the rapid determination of glucose. Since the device is very small, glucose sample whose volume is only 2 μ1 can be successfully determined. Pulse voltammetry is shown to be an effective approach for making the sensing device work without any attachments such as magnetic stirrer and pump. The transient sensor output, oxidizing current for the hydrogen peroxide generated by the immobilized glucose oxidase, shows a good linearity in the glucose concentration range from 1 mM to 20 mM.     

Nickel/Copper Bilayer‐modified Screen Printed Electrode for Glucose Determination in Flow Injection Analysis

This work reports about the performance of a Ni/Cu‐modified screen printed electrodes (SPE/Ni/Cu), prepared by physical vapor deposition (PVD) in an oblique angle configuration (OAD), for non‐enzymatic glucose sensing applications. SPE/Ni/Cu electrodes showed an excellent reversibility and a catalytic behavior for detection of glucose that were controlled by the diffusion of reactants up to the active sites at the electrode surface. The study with a flow injection analysis (FIA) setup of the main experimental variables affecting the detection process has shown that the developed electrode system had an excellent glucose sensitivity of 1.04 A M⁻¹cm⁻² (R²:0.999), a linear response up to 1 mM, a limit of detection of 0.33 μM and a time of analysis of ca. 30 s per sample. The selectivity of the sensor was checked against various interferences, including ascorbic acid, uric acid, acetaminophen and other sugars, in all cases with excellent results. The feasibility of using this sensor for practical applications was successfully confirmed by determining the glucose concentration in different commercial beverages.     

Fabrication of Photoelectrochemical Glucose Biosensor in Flow Injection Analysis System Using ZnS/CdS‐Carbon Nanotube Nanocomposite Electrode

In this work, a photoamperometric glucose biosensor based on glucose oxidase (GODx) was developed in flow injection analysis (FIA) system using ZnS‐CdS quantum dot (QD) modified multiwalled carbon nanotube/glassy carbon electrode (ZnS‐CdS/MWCNT/GCE). Cyclic voltammograms of the proposed electrode (GODx/ZnS‐CdS/MWCNT/GCE) showed a pair of well‐defined reversible redox peak attributing that direct electron transfer between the protein and electrode. The current of the reduction peak became more cathodic in the presence of O₂ due to the electrocatalytic activity of the electrode towards the reduction of dissolved O₂, but reduction current shifted to a less negative value upon addition of glucose in the solution. The obtained CV currents were affected by the irradiation of the electrode surface. Thus, the photoelectrochemical biosensing of glucose in the FIA system was studied by monitoring of the changes in the electrocatalyzed reduction peak current of dissolved O₂ at the proposed electrode dependent on glucose concentration. The proposed photoelectrochemical FIA method has a linear response to glucose ranging from of 0.01 to 1.0 mM with detection limit of 3.0 μM under optimized conditions. Photoelectrochemical biosensor was successfully fabricated in FIA system for selective, sensitive and repeatable detection of glucose and has been satisfactorily applied to determination of glucose in real sample.     

Biosensor for determination of glucose and sucrose in fruit juices by flow injection analysis

Glucose and sucrose were measured with an amperometric method by using the flow injection analysis technique. A carbon paste electrode with a renewable surface containing glucose oxidase, horseradish peroxidase, and ferrocene was used in combination with the soluble enzymes invertase and mutarotase. The effect of invertase, mutarotase, and ascorbic acid on the electrode response was examined. Glucose and sucrose concentrations were determined with <3% errors. The proposed method for glucose and sucrose measurements was validated in real samples of fruitjuices. The results were also compared with those obtained with the ultraviolet method.     

Electrochemical study of sulfadiazine on a novel phthalocyanine-containing chemically modified electrode

In this paper, cobalt tetraaminophthalocyanine (CoPc) was successfully deposited onto a carbon nanotubes modified electrode by consecutive cyclic scanning in supporting electrolyte containing CoPc to form phthalocyanine-containing chemically modified electrode. The electrochemistry of sulfadiazine was studied by voltammetric method and flow injection analysis at the new modified electrode. Compared with glassy carbon electrode, the new modified electrode exhibited exciting performance including low oxidation potential, high current response and promising flow injection response.     

An integrated bienzyme glucose oxidase-fructose dehydrogenase-tetrathiafulvalene-3-mercaptopropionic acid-gold electrode for the simultaneous determination of glucose and fructose

A bienzyme biosensor for the simultaneous determination of glucose and fructose was developed by coimmobilising glucose oxidase (GOD), fructose dehydrogenase (FDH), and the mediator, tetrathiafulvalene (TTF), by cross-linking with glutaraldehyde atop a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM) on a gold disk electrode (AuE). The performance of this bienzyme electrode under batch and flow injection (FI) conditions, as well as an amperometric detection in high-performance liquid chromatography (HPLC), are reported. The order of enzyme immobilisation atop the MPA-SAM affected the biosensor amperometric response in terms of sensitivity, with the immobilisation order GOD, FDH, TTF being selected. Similar analytical characteristics to those obtained with single GOD or FDH SAM-based biosensors for glucose and fructose were achieved with the bienzyme electrode, indicating that no noticeable changes in the biosensor responses to the analytes occurred as a consequence of the coimmobilisation of both enzymes on the same MPA-AuE. The suitability of the bienzyme biosensor for the analysis of real samples under flow injection conditions was tested by determining glucose in two certified serum samples. The simultaneous determination of glucose and fructose in the same sample cannot be performed without a separation step because at the detection potential used (+0.10 V), both sugars show amperometric response. Consequently, HPLC with amperometric detection at the TTF-FDH-GOD-MPA-AuE was accomplished. Glucose and fructose were simultaneously determined in honey, cola softdrink, and commercial apple juice, and the results were compared with those obtained by using other reference methods.     

Detection of zeptomolar concentrations of alkaline phosphatase based on a tyrosinase and horse-radish peroxidase bienzyme biosensor

A bienzyme biosensor based on tyrosinase and horse-radish peroxidase is described in a flow injection analysis and cyclic voltammetry for measurement of phenol. Tyrosinase and horse-radish peroxidase were immobilized on the surface of a glassy carbon electrode by bovine serum albumin and glutaric dialdehyde. Phenol was oxidized by tyrosinase and horse-radish peroxidase via catechol to o-quinone in the presence of oxygen and hydrogen peroxide. The o-quinone was reduced to produce catechol (the substrate recycling) on the electrode surface. The enhanced sensitivity of the bienzyme electrode to phenol was observed in the flow injection system comparing with tyrosinase and horse-radish peroxidase monoenzyme electrodes. The mechanisms for enhanced amperometric response to phenol of bienzyme electrode were discussed. The biosensor was used to detect alkaline phosphatase (ALP). A detection limit of 1.4×10⁻¹⁵ M ALP (140 zmol/100 μl) was obtained after 1 h incubation with phenyl phosphate.