基于碳纳米管组装电化学传感器测定金丝桃苷的含量

目的:采用单壁碳纳米管(SWCNTs)修饰玻碳电极(GCE),制作电化学传感器,研究金丝桃苷在传感器表面的电化学行为,建立一种简单的、高灵敏的金丝桃苷的电化学检测新方法。方法:将羧基化SWCNTs滴在GCE表面,采用循环伏安法(CV)研究了金丝桃苷在传感器表面的电化学行为,并对测量条件进行了优化。结果:和裸GCE电极相比较,金丝桃苷在GCE/SWCNTs电极表面的氧化峰电流和还原峰电流均急剧增加,氧化峰电流和还原峰电流与扫描速度的平方根成正比,说明金丝桃苷在修饰电极表面的反应是受扩散控制的过程。在缓冲液的pH为6.0、碳纳米管的用量为10 μL、检测电位为0.34 V的优化条件下时,金丝桃苷浓度在3.0×10-9~1.0×10-7范围内与氧化电流呈现良好的线性关系,检出限为2.41×10-9 mol/L(S/N=3)。结论:该方法灵敏度高,简单易行,具有较好的重现性及稳定性,可用于金丝桃苷的检测。     

基于1T-WS2@AuNPs复合材料的白芸豆酯酶电化学生物传感器构建及其杀螟硫磷检测应用

通过简单的自组装方法制备了由1T相二硫化钨纳米片（1T-WS2）和纳米金（AuNPs）组成的新型纳米复合材料1T相二硫化钨/纳米金（1T-WS2@AuNPs）。利用其优异的理化性能对传感信号增敏,与来源于白芸豆的酯酶,共同构建了一种基于1T-WS2@AuNPs纳米复合材料的白芸豆酯酶电化学生物传感器,用于有机磷农药杀螟硫磷的低成本、高灵敏检测。采用扫描电子显微镜、透射电子显微镜以及X射线光电子能谱对所制材料的形貌和组成进行表征。对底液pH值、复合材料负载量及酶负载量等电化学检测条件进行考察。在最优条件下,CS/KbE/1T-WS2@AuNPs/GCE传感器对杀螟硫磷的线性检测范围为0.1～2 000 μg/L,标准曲线的相关系数为0.992,检出限为0.04 μg/L。此传感器具有良好的重复性、稳定性与抗干扰能力。将其用于实际农产品中杀螟硫磷的检测,回收率为96.16%～109.60%,表明所建传感器在有机磷农药检测方面具有潜在应用价值。     

基于Nafion/Hb/Fe3O4@Cs/GCE传感器检测油炸食品中丙烯酰胺

目的 制备Nafion/Hb/Fe3O4@Cs/GCE传感器, 并应用于油炸食品中丙烯酰胺(acrylamide, AM)的检测分析。方法 制备Fe3O4@碳球纳米复合材料(Fe3O4 carbon sphere nanocomposites, Fe3O4@Cs), 并复合Nafion和血红蛋白(hemoglobin, Hb), 以玻碳电极(glassy carbon electrode, GCE)为工作电极制备Nafion/Hb/Fe3O4@Cs/GCE传感器, 通过对固载方式、Hb固载量、加成温度以及加成时间的优化确定Nafion/Hb/Fe3O4@Cs/GCE对丙烯酰胺进行定量检测的最佳检测条件。结果 Fe3O4@Cs导电性良好, 能显著提高Nafion/Hb/Fe3O4@Cs/GCE传感器的灵敏度。AM与Hb的加成率与其浓度负对数在1×10?5~1×10?9 mol/L范围内呈良好的线性关系, 线性方程为Y=?5.254X+60.01 (X为AM浓度的负对数), r2=0.9973, 检出限为2.134×10?10 mol/L, 加标回收率在95.6%~98.4%之间, 相对标准偏差小于1.45%。结论 该方法简单、方便快捷, 适用于油炸食品中AM的定量分析。     

基于还原氧化石墨烯/碳纳米管-纳米金复合纳米材料的阻抗型电化学适配体传感器检测铜绿假单胞菌

基于还原氧化石墨烯/碳纳米管-纳米金复合纳米材料制备电化学阻抗传感器检测铜绿假单胞菌。采用电化学沉积的方法将氧化石墨烯/碳纳米管修饰在电极表面，并将氧化石墨烯电化学还原。随后将纳米金沉积在电极表面，最后将巯基修饰的铜绿假单胞菌适配体通过金硫共价键结合在纳米金表面，制成工作电极。用扫描电镜观察合成的还原氧化石墨烯/碳纳米管-纳米金材料的形貌。用循环伏安法对组装电极的每一步进行电化学表征。当铜绿假单胞菌在适配体修饰的电极表面孵育后，适配体会将目标菌捕获在电极表面，阻碍电极表面电子传输，导致阻值上升，根据电阻变化值可实现对目标菌的定量检测，检测线性范围为10～106 CFU/mL，检出限可达4 CFU/mL，本实验方法是已知的检测铜绿假单胞菌灵敏度最高的电化学方法。     

基于Pd/MWCNTs/玻碳电极的电化学传感器检测水样中的羟胺

目的 采用Pd/MWCNTs纳米复合材料修饰玻碳电极构建电化学传感器,检测养殖水样及水产饲料中羟胺（NH2OH）的含量。方法 采用乙二醇还原法制备Pd纳米颗粒负载于碳纳米管上制备Pd/MWCNTs纳米材料,运用XRD(X-ray diffraction)和TEM (transmission electron microscopy) 手段对材料进行表征,构建基于Pd/MWCNTs/GCE的电化学传感器检测羟胺。 结果 在优化的工作条件下,Pd/MWCNTs纳米复合材料修饰电极检测羟胺线性检测范围2.0 μmol/L-1.4 mmol/L,检测下限达0.60 μmmol/L (S/N = 3),灵敏度为61.48 μA/mmol/L,是MWCNTs修饰电极检测灵敏度的10倍左右。结论 复合材料制备的传感器检测羟胺具有灵敏度高、线性范围宽、检测下限低的特点,可用于抗氧化剂羟胺的检测。     

抗杀螟硫磷纳米抗体表达、纯化策略研究及检测方法建立

为了高效制备高纯度的抗杀螟硫磷纳米抗体,本研究对一株低表达水平的重组抗杀螟硫磷纳米抗体在大肠杆菌中的表达条件进行优化,以IPTG浓度、温度为自变量,Nb表达量为因变量进行单因素实验,同时对抗体纯化方法进行研究。结果表明,在37℃、无IPTG条件下抗杀螟硫磷纳米抗体表达量最高,达到6 mg/L,并且发现IPTG用量与诱导温度存在交互效应,通过Ni亲和层析与凝胶过滤层析两步纯化法,最终得到了纯度98%以上的抗杀螟硫磷抗体,表明该表达与纯化策略可以高效制备抗杀螟硫磷纳米抗体。利用所获得的纳米抗体,建立了icELISA检测方法,其IC₅₀为5.81 ng/mL,检出限为0.25 ng/mL,检测范围为0.78～43.07 ng/mL。选择生菜和白菜为样品进行添加回收实验,添加回收率在93.3%～111.7%之间,变异系数(CV)值在2.3%～18.2%之间。基于杀螟硫磷纳米抗体所建立的方法灵敏度高,能够满足国标规定的杀螟硫磷监测需求,可用于杀螟硫磷的快速筛查。本研究为开发高效快速的杀螟硫磷免疫检测方法奠定了基础。     

基于铋镍双金属有机骨架电化学传感器检测食品包装中对特辛基苯酚

目的 构建一种新型电化学传感器,并用于快速检测食品包装中的对特辛基苯酚[p-(tert-octyl)phenol,POP]。方法 利用溶剂热法合成铋镍双核金属有机骨架(bismuthnickelbimetallicmetal-organic frameworks, Bi-Ni-BTC),通过超声自组装的方法将Bi-Ni-BTC与多壁碳纳米管(multi walled carbon nanotubes,MWCNTs)制备复合材料Bi-Ni-BTC@MWCNTs,并滴涂成膜于玻碳电极(glassycarbonelectrode,GCE)表面,构建电化学传感器Bi-Ni-BTC@MWCNTs/GCE。采用循环伏安法、电化学阻抗谱法、扫描电子显微镜、X-射线衍射、傅立叶红外光谱等方法进行表征分析,并通过可行性实验初步评价该传感器的性能。使用线性扫描伏安法(linear sweep voltammetry, LSV),通过调整配体比例、修饰量、缓冲溶液的种类、pH、富集时间、富集电位、扫描速度等优化传感器的性能。结果 GCE表面上滴涂电极修饰液3次,共3层,修饰量共18μg、pH 7.0磷酸盐缓...     

原位生长α-Co (OH)2纳米片修饰电极快速检测亚硝酸盐

本工作以硝酸钴为前驱体,通过一步电沉积法在玻碳电极表面原位生长氢氧化钴纳米片,构建了电化学传感器,研究了其对NO2-离子的电催化行为,建立了快速测定NO2-离子的电化学方法。通过扫描电子显微镜（Scanning electron microscope,SEM）、能量散射光谱（Elemental energy spectrum analysis,EDX）和电化学技术对所获得的纳米材料的形貌和性能进行表征,进一步研究该修饰电极快速检测NO2-离子的电化学行为和电催化机理。结果表明,同一浓度NO2-离子在不同扫描速度与电流响应间成正比关系,得到Co(OH)2/GCE界面的电化学过程受吸附控制。Co(OH)2/GCE对NO2-离子展现了良好的电催化性能,检测线性范围为1~15 mmol/L,检测限为0.29 mmol/L（S/N=3）。该传感器具有快速制备、催化活性好、易操作以及检测耗时短等特点,适用于亚硝酸盐的现场快速筛查。     

一种新型过氧化氢传感器的构建及其在牛奶中的应用

为构建一种新型过氧化氢生物传感器,将血红蛋白吸附在聚吡咯膜为基底的金纳米颗粒上,通过SEM、AFM、XPS、CV和EIS表征修饰电极并将该传感器用于牛奶中过氧化氢的检测。结果表明各材料成功的修饰到电极表面,且纳米金颗粒的粒径约为15 nm,Hb/AuNPs/Ppy/GCE的最佳制备条件为吡咯聚合电量3.0×10-3 C,PBS溶液pH6.5,支持电解质溶液pH7.0。该传感器对过氧化氢的检出限为0.2 μmol/L(S/N=3),检测时间12 s。此外,所构建的传感器具有良好的稳定性和选择性,金纳米颗粒大,比表面积提供更多的位点固载血红蛋白,同时血红蛋白和纳米金颗粒对过氧化氢具有良好的协同催化效果。该传感器监测牛奶中过氧化氢的加标回收率为92.7%~116.0%。结果表明,Hb/AuNPs/Ppy/GCE是一种有前途的电化学生物传感器。     

纳米金-壳聚糖/多壁碳纳米管修饰的玻碳电极检测水中微量的孔雀石绿

目的制备基于纳米金-壳聚糖/多壁碳纳米管修饰的玻碳电极,用于检测水样中微量的孔雀石绿。方法实验利用电沉积法首先在玻碳电极表面沉积金纳米颗粒,然后利用溶剂蒸发法在纳米金层表面再修饰混有壳聚糖的羧基化多壁碳纳米管。实验设计以多壁碳纳米管/纳米金共修饰的玻碳电极作为电化学传感元件,采用循环伏安法(CV)和微分脉冲伏安法(DPV)检测MG。结果表明电极的修饰膜可加速MG的电子传递速率,促进电位变化,并显著增强MG的氧化峰电流。得到的差分脉冲峰电流与孔雀石绿浓度对数值在2.5×10-9～2.5×10-4 mol/L范围内呈良好线性关系,检测限为9.3×10-10 mol/L。结论本研究制备的基于纳米金-壳聚糖/多壁碳纳米管修饰玻碳电极的电化学传感器适于孔雀石绿的快速、灵敏检测。     

Electrochemical Determination of Bisphenol A at Multi-walled Carbon Nanotubes/Poly (Crystal Violet) Modified Glassy Carbon Electrode

Bisphenol A (BPA) can disrupt endocrine system. In this study, a novel and sensitive electrochemical senor based on multi-walled carbon nanotubes (MWCNTs) and poly crystal violet (PCV) modified glass carbon electrode (GCE) was developed for determination of BPA. The morphologies and properties of modified electrode were characterized by scanning electron microscopy and electrochemical impedance spectra. Compared with bare GCE and other modified electrodes, this MWCNTs/PCV/GCE exhibited an excellent electrocatalytic role for the oxidation of BPA by significantly enhancing the current response and decreasing the BPA oxidation overpotential. Under optimum conditions, the electrochemical sensor can be applied to the quantification of BPA by linear sweep voltammetry (LSV) with a linear range covering 5 × 10^?8–1 × 10^?4 mol L^?1 (with a correlation coefficient of 0.9969), and the limit detection was 1 × 10^?8 mol L^?1 (S/N = 3). The recovery was between 98.38 and 103.51% in real plastic samples. This strategy might enable more opportunities for the electrochemical determination of BPA in practical applications.     

Electrochemical Determination of Tert-Butyl Hydroquinone in Edible Oil Samples at Poly (Crystal Violet) Modified Glassy Carbon Electrode

The synthetic phenolic antioxidant tert-butyl hydroquinone (TBHQ) is frequently associated to adverse health effects. A polymerized film of crystal violet (CV) was prepared on the surface of a glass carbon electrode (GCE) by electropolymerization in alkaline solution, and then the modified electrode was successfully used to determine TBHQ. This electrode was characterized by scanning electron microscopy and electrochemical impedance spectra. The voltammetric behavior of TBHQ over an extended pH range using cyclic voltammetry at poly (crystal violet) modified glassy carbon electrode (PCV/GCE) was also studied. The resulting electrode exhibited excellent electrocatalytic activity towards the oxidation of TBHQ, and this was confirmed by the observed increased redox peak currents and shifted potentials. The electrochemical sensor can be applied to the quantification of TBHQ with a linear range covering 5?×?10^?7–1?×?10^?4 mol?·?L^?1 (with a correlation coefficient of 0.9969) and the limit detection was 3?×?10^?8 mol?·?L^?1(S/N?=?3). The recovery was between 97.1 and 102 % in edible oil samples. The electrochemical sensor method was also compared with a HPLC method, which proves its capability in commercial market surveillance.     

Sensitive electrochemical determination of luteolin in peanut hulls using multi-walled carbon nanotubes modified electrode

A simple and highly sensitive electrochemical method was developed for the determination of trace-level luteolin, based on the multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE). The electrochemical behaviours of luteolin indicate that MWNTs modified glassy carbon electrode (MWNTs/GCE) can greatly enhance the electrocatalytic activity towards the redox of luteolin. It leads to a considerable improvement of the redox peak current for luteolin and allows the development of a highly sensitive voltammetric sensor for the determination of luteolin. A series of experimental parameters including the pH of supporting electrolyte, accumulation potential and time were optimised. The results showed that the oxidative peak currents increased linearly with the concentration of luteolin in the range of 2.0 × 10⁻¹⁰ to 3.0 × 10⁻⁹ M, with a detection limit of 6.0 × 10⁻¹¹ M (S/N = 3). The analytical performance of this sensor has been evaluated for detection of luteolin in peanut hulls as a real sample.     

Sensitive and Selective Determination of Riboflavin in Milk and Soymilk Powder by Multi-walled Carbon Nanotubes and Ionic Liquid [BMPi]PF<Subscript>6</Subscript> Modified Electrode

A novel electrochemical method to detect riboflavin was proposed using a multi-walled carbon nanotubes and ionic liquid N-butyl-N-methyl-piperidinium hexafluorophosphate composite film modified glassy carbon electrode (MWNTs-[BMPi]PF₆/GCE). A well-defined CV behavior with a pair of sensitive and well-shaped redox peak was observed, and the response value of riboflavin at MWNTs-[BMPi]PF₆/GCE is much higher than that at MWNTs/GCE in 0.1 mol L^?1 HAc-NaAc buffer solution (pH 4.5). The electrochemical approach based on a sensitive DPV analytical signal exhibits an excellent analytical performance with a wide linear range (2.6 × 10^?8 to 1.3 × 10^?6 mol L^?1) and low detection limit (4.7 × 10^?9 mol L^?1) for the riboflavin. Moreover, the proposed method possesses a potential practical application value and can be employed for the quantitative analysis of trace riboflavin with a recovery of 95.8–102.4 % in food samples such as milk and soymilk powder.     

石墨烯/四氧化三钴电化学传感器的建立及饼干中香兰素检测分析

本文将石墨烯（GR）滴涂在玻碳电极（GCE）后,再通过循环伏安法电聚合氧化Co（COOH）₂制得Co₃O₄/GR/GCE修饰电极作为食品中检测香兰素的新型电化学传感器。通过扫描电镜技术对Co₃O₄/GR复合纳米材料进行了表征并优化了实验条件。结果表明,当1 mg/mL GR滴涂量为8 μL,Co（COOH）₂聚合圈数为20圈,0.1 mol/L pH 4.5磷酸缓冲溶液中,香兰素在该传感器下线性关系良好（0.1～80 μmol/L）,线性方程为:I_p （μmol/L）=0.1518C+0.5103 （R2=0.997）,检测限为0.033 μmol/L （S/N=3）。将此方法应用于饼干样品中香兰素检测,回收率良好,相对标准偏差仅1.47%。综上,该电化学传感器灵敏度较高、稳定性良好,在实际样品检测中具有可行性,拥有广阔的应用前景。     

Carbon Nanotube–Ionic Liquid (CNT–IL) Nanocamposite Modified Sol-Gel Derived Carbon-Ceramic Electrode for Simultaneous Determination of Sunset Yellow and Tartrazine in Food Samples

Carbon-ceramic electrode modified with multi-walled carbon nanotubes–ionic liquid (MWCNTs–IL) nanocomposite was constructed. This electrode was used for electrochemical determination of food dyes Sunset Yellow (SY) and tartrazine (Tz). The modified electrode based on high surface area and high ionic conductivity of nanocomposite exhibited electrocatalytic effect for oxidation of SY and Tz; also, oxidation peak potentials of SY and Tz effectively separated on modified electrode, and their simultaneous determination was possible. Operational parameters, such as the amount of MWCNTs in suspension, IL volume, solution pH, and scan rate, which affect the analytical performance of determination, were optimized. The present electrode behaved linearly to Sunset Yellow and tartrazine in the concentration range of 4?×?10^?7 to 1.1?×?10^?4?M and 3?×?10^?6 to 0.7?×?10^?4?M with a detection limit of 10^?7?M (0.045 mg?L^?1) and 1.1?×?10^?6?M (0.59 mg?L^?1), respectively. The proposed method was successfully utilized for simultaneous determination of SY and Tz in different food samples, and the obtained results were in good agreement to those obtained by HPLC method.