以新亚甲蓝为介体的过氧化氢传感器的电化学行为研究

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)修饰于玻碳电极表面,制成一种新型的电流型H2O2传感器。探讨了该传感器在0·1mol/L磷酸缓冲溶液(pH=7·0)中的电化学性质。结果表明,NMB作为介体能够有效地在辣根过氧化酶和电极之间传递电子。测得电子转移系数为0·861,表观反应速率常数为1·27s-1。研究了传感器对H2O2的响应及动力学性质,米氏常数为8·27μmol/L,线性响应范围为2·5~100μmol/L。同时研究了pH、缓冲容量及温度等因素对H2O2传感器的影响。     

电化学免疫传感器测定鸡肉组织中青霉素的研究

将玻碳电极（GCE）表面氧化处理后,用戊二醛（GA）作交联剂,把新亚甲蓝 (NMB) 与辣根过氧化酶 (HRP) 标记的青霉素多克隆抗体 (Ab?) 修饰到电极表面,制成高灵敏电流型青霉素免疫传感器。通过循环伏安法考察了电极表面的电化学特性,并对鸡肉中青霉素的残留进行了定量的研究。结果表明该传感器对鸡肉中含有的青霉素检测的线性范围是5～45ng/g,相关系数为0.9747,检出限为1.90ng/g。     

电化学免疫传感器测定牛奶中的青霉素

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)标记的青霉素多克隆抗体(Ab*)修饰于玻碳电极表面,制成电流型免疫传感器;考察了该传感器的电化学行为和对H2O2的电化学响应.结果表明,NMB作为介体能有效地传递电子,传感器对H2O2具有很好的催化作用.用此传感器对牛奶中的青霉素进行检测,其线性范围为0.25～3.00ng/mL (R=0.984),检出限为0.298ng/mL.     

电化学免疫法测定鸡肉组织中青霉素

将玻碳电极(GCE)表面氧化处理后,用戊二醛(GA)作交联剂,将新亚甲蓝(NMB)及辣根过氧化酶(HRP)标记的青霉素多克隆抗体(Ab*)修饰到电极表面,制成高灵敏电流型青霉素免疫传感器. 通过循环伏安法考察了电极表面的电化学特性,并对鸡肉中青霉素的残留进行了定量的研究. 结果表明,传感器对鸡肉中含有的青霉素检测的线性范围是5～45 ng/g,相关系数为0.974 7,最低检出限为1.90 ng/g. 考察了蛋白沉淀剂的沉淀效果,发现运用饱和硫酸铵对鸡肉中蛋白和脂类的沉淀效果最好. 样品回收率最高为74.5%. 干扰性实验表明,交叉干扰和鸡肉中其它成分干扰均较小. 修饰的电极稳定性较好,可用于实际肉样中青霉素含量的测定.     

Nafion 膜固定的新亚甲基蓝为介体生物传感器

以Nafion膜固定的新亚甲基蓝为辣根过氧化物酶和玻碳电极间的电子传递介体,制成电流型单酶过氧化氢生物传感器和双酶葡萄糖生物传感器。探讨了工作电位、pH值、温度和干扰物质等对生物传感器的影响。     

The electrochemical behavior of hydrogen peroxide sensor based on new methylene blue as mediator

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)修饰于玻碳电极表面,制成一种新型的电流型H2O2传感器。探讨了该传感器在0·1mol/L磷酸缓冲溶液(pH=7·0)中的电化学性质。结果表明,NMB作为介体能够有效地在辣根过氧化酶和电极之间传递电子。测得电子转移系数为0·861,表观反应速率常数为1·27s-1。研究了传感器对H2O2的响应及动力学性质,米氏常数为8·27μmol/L,线性响应范围为2·5~100μmol/L。同时研究了pH、缓冲容量及温度等因素对H2O2传感器的影响。     

辣根过氧化物酶生物传感器检测硫化物的研究

采用酸性溶胶法在碳纳米管(CNT)上负载纳米二氧化钛(TiO2)颗粒,并制备了CNT-TiO2修饰电极,利用TiO2与辣根过氧化物酶(HRP)间的静电吸附实现了HRP在CNT-TiO2修饰电极表面的固定。利用硫化物对HRP的抑制作用实现了对硫化物的检测。其峰电流值与硫化物的浓度在0.75×10-7～10.5×10-6mol/L范围内呈线性关系。方法的检出限为(3S/N)0.206×10-7mol/L。     

聚中性红作电子转移介体的过氧化氢生物传感器

提出一种新的第二代电流型生物传感器。将易溶于水的电子转移介体中性红经电聚合在石墨电极表面形成一层致密、稳定的膜 ,有效的减少了其流失。并在辣根过氧化酶的表面覆盖一层明胶 ,再用戊二醛交联制备了H2 O2 传感器 ,使固定化酶保持了较高活性。该生物传感器具有较宽的线性范围 :2 .0× 10 - 5～ 2 .5×10 - 2 mol L ;检出限为 1.8× 10 - 5mol L ,达到 95 %稳态电流所用时间 <2 0s。     

基于纳米金/硫堇层层自组装的新型电流型酶-癌胚抗原免疫传感器

将Nafion 膜固定在金电极(Au)表面, 通过静电吸附和共价键合作用将硫堇(Thi)和纳米金颗粒(nano-Au)层层自组装到Nafion膜修饰的金电极表面. 再通过形成的纳米金单层吸附癌胚抗体(anti-CEA), 最后用辣根过氧化物酶(HRP)代替牛血清白蛋白(BSA)封闭电极上的非特异性吸附位点, 并同时起到放大响应电流信号的作用, 从而制得高灵敏、高稳定电流型酶-癌胚抗原(CEA)免疫传感器. 通过循环伏安和交流阻抗考察了电极表面的电化学特性, 并对该免疫传感器的性能进行了详细的研究. 该传感器对CEA检测的线性范围为2.5~80.0 ng/mL, 检测限为0.90 ng/mL.     

以新亚甲基蓝为电子媒介体的大肠杆菌微生物燃料电池的研究

以新亚甲基蓝(NMB) 为电子媒介体, 大肠杆菌为微生物催化剂, 设计了微生物燃料电池(MFC). 该MFC的开路电压为0.760 V, 短路电流为1.108 mA, 最大输出功率为116 mW/m2, 此时所对应的电流密度为390 mA/m2. 比较了中性红(NR)和NMB作为电子媒介体对MFC性能的影响. 实验结果表明, 以NMB为电子媒介体的MFC的开路电压比以NR为电子媒介体的MFC的开路电压低, 但其开路电压达到稳定所需要的时间更短, 而且其短路电流比后者高. 当放电电流大于114 mA/m2时, 前者比后者的输出功率高, 在负载1000 Ω放电时, 前者比后者有更好的稳定性.     

基于聚硫堇/亚甲基蓝和纳米金放大的免疫传感器检测贝类毒素大田软海绵酸

采用聚硫堇(PTH)修饰电极为传感界面提供一个生物修饰功能基质膜,借助纳米金(GNPs)的导电性、生物相容性与高比表面积特性实现抗体的有效固定,并以亚甲基蓝(MB)为电子媒介加速电极表面电化学反应的电子传递,构建了一种高灵敏的非标记电化学免疫传感器,用于贝类毒素大田软海绵酸(OA)的检测。当分子结构中含有羧基和酚基的OA与其抗体特异性结合后,生成以阴离子形式存在的抗原-抗体复合物,阻碍了传感器表面电子的传递,导致峰电流下降。利用免疫反应前后峰电流的变化,可对OA进行特异性识别和准确定量。在优化实验条件下,OA浓度的对数在0.2~100 μg/L范围内与其峰电流的变化值(ΔI)呈线性相关,线性方程为ΔI=1.721 7+1.083 6lgρ,相关系数为0.992 0,检出限为0.1 μg/L。该免疫传感器重现性好、特异性强,用于实际贝类样品的测定,回收率为85.3%~112%。     

Determination of Some Phenothiazines Compounds in Pharmaceuticals and Human Body Fluid by Electrocatalytic Oxidation at a Glassy Carbon Electrode Using Methylene Blue as a Mediator

Abstract

A glassy carbon electrode plus Methylene blue as a mediator was employed to study and sense the electrocatalytic oxidation of phenothiazines, including chlorpromazine, perphenazine, promazine, and fluphenazine, using cyclic voltammetry and chronoamperometry as diagnostic techniques. The electron-transfer coefficient, alpha (= 0.45), for phenothiazines compounds at the surface of glassy carbon electrode was determined using a cyclic voltammetry technique. It was found that under a selected pH (8.6) the peak current due to the oxidation of Methylene blue at the surface of the electrode that occurrs at a potential of about ? 180 mV is proportional to the phenothiazines concentration. Linear analytical curves were obtained in the ranges of 1.0 × 10^?6 ? 2.1 × 10^?4 mol L^?1 for the phenothiazines compounds. The influences of potentially interfering substances on the current response of the system were examined. The method was used for the determination of phenothiazines compounds, including chlorpromazine, perphenazine, promazine, and fluphenazine in human.     

Determination of Phenolic Compounds Based on Co‐Immobilization of Methylene Blue and HRP on Multi‐Wall Carbon Nanotubes

This work evaluated an amperometric biosensor based on multi‐wall carbon nanotubes (MWCNT), chemically modified with methylene blue (Met) and horseradish peroxidase (HRP), for detection of phenolic compounds. The dependences of the biosensor response due to the enzyme immobilization procedure, HRP amounts, pH and working potential were investigated. The amperometric response for catechol using the proposed biosensor showed a very wide linear response range (1 to 150 μmol L^?1), good sensitivity (50 nA cm^?2 μmol^?1 L), excellent operational stability (after 300 determinations the response remained at 97%) and very good storage stability (lifetime>3 months). Based on all these characteristics, it is possible to affirm that the material is promising for phenol detection due to its good electrochemical response and enzyme stabilization. The biosensor response for various phenolic compounds was investigated.     

Methylene Blue Poly(Vinyl Chloride) Membrane Electrode Based on the Methylene Blue-Teteraphenylborate Ion-Pair Complex and Its Application to Pharmaceutical Analysis

Abstract

A methylene blue (MB) poly (vinyl chloride) membrane electrode based on MBtetraphenylborate (TPB) ion-pair complex is described. The linear response covers the range 1x10^?2 - 1x10^?6 mol dm^?3 MB solution, with a slope of 56.5±0.5 mv/decade (pH range 3.0-1 0.0). The detection limit is 7.75x 10^?7 mol dm^?3. The electrode shows stability, good reproducibility and fast response. Interferences from common inorganic cations and some organic bases are negligible. These characteristics of the electrode enabled it to be used successfully for the determination of MB in injection.     

A Signal‐Amplified Electrochemical Immunosensor Based on Prussian Blue and Pt Hollow Nanospheres as Matrix

Through electrodepositing Prussian blue (PB) and chitosan (CS), then casting Pt hollow nanospheres (HN‐Pt) and assembling CA19‐9 antibody on the electrode surface, an immunosensor was achieved. A new signal amplification strategy based on PB and HN‐Pt toward the electrocatalytic reduction of H₂O₂ was employed when performing the determination. The resulting immunosensor showed a high sensitivity, broad linear response to carbohydrate antigen 19‐9 (CA19‐9) in two ranges from 0.5 to 30 and 30 to 240 U mL^?1 with a low detection limit of 0.13 U mL^?1 (S/N=3). Moreover, it displayed good reproducibility and stability, and would be potentially attractive for clinical immunoassay of CA19‐9.     

基于聚吡咯修饰膨胀石墨电极的甲胎蛋白电化学免疫传感器

构建了测定人血清中甲胎蛋白(AFP)的电化学免疫传感器。此免疫传感器的制备采用恒电位法在膨胀石墨(EG)电极表面合成聚吡咯(PPy),再以戊二醛(GA)作为交联剂,固定辣根过氧化酶标记的AFP抗体(HRP-anti-AFP)。此免疫传感器在含AFP的溶液中于35℃温育50 min后,再在传感器表面修饰普鲁士蓝(PB)作为电子介体,抗原抗体免疫结合产生的免疫复合物会导致HRP对PB催化氧化的效率降低。在优化条件下,AFP的浓度在0.01～300μg/L范围内呈线性关系,检出限为6.25 pg/mL(S/N=3)。这种基于PPy修饰EG电极的免疫传感器制备简单,灵敏度高且价格低廉,有望成为一次性电化学免疫传感器。