聚电解质PSS/PDDA分子沉积膜表面性能研究

PSS PDDAMD膜紫外 可见吸光度与层数呈线性关系 ,其延长线基本为零证实了是一单分子层层状沉积过程 ;利用接触角测量仪跟踪MD膜沉积过程 ,其结果表明 ,层数较少时PSS PDDAMD膜表面润湿性呈“奇 偶”性规律变化 ,层数较多时规律性不明显 ,这说明聚电解质MD膜结构缺陷随着层数的增加有增大趋势 ;通过对原子力显微镜 (AFM)测定结果的分析 ,进一步证实了多层PSS PDDAMD膜存在结构缺陷 .     

基于石墨烯修饰电极的电化学生物传感

石墨烯是一种具有单原子厚度的二维碳纳米材料,具有大的比表面积、高的导电性和室温电子迁移率,以及优异的机械力学性能.石墨烯还具有电化学窗口宽,电化学稳定性好,电荷传递电阻小,电催化活性高和电子转移速率快等电化学特性.化学修饰石墨烯,特别是氧化石墨烯(GO)和还原氧化石墨烯(rGO),可以被宏量、廉价地制备出来.它们具有可加工性能,可以被组装、加工或复合成具有可控组成和微结构的宏观电极材料.因此,石墨烯及其化学修饰衍生物是用于电化学生物传感的独特而诱人的电极材料.例如,GO是一种化学修饰石墨烯,也是石墨烯的重要前驱体;其边缘具有大量的羧基可用于共价固定酶,从而能实现酶电极的生物检测.在GO上的不可逆蛋白吸附也可以促进蛋白质的直接电子转移以提高其电化学检测性能.但是,GO大量的含氧官能团破坏了石墨烯本征的共轭结构,降低了其电学性能并限制了其实际应用.GO可以通过化学、电化学、热还原等技术转化成rGO,从而能部分修复其共轭结构,提高其导电性与传感性能.另一方面,石墨烯是一种零带隙材料;原子掺杂可以调控其能带结构,提高其电催化性能.石墨烯材料也常常需要通过与其它功能材料的复合进一步改善其可分散与可加工性能,提高其电催化活性和电化学选择性.本文综述了本征石墨烯(包括GO,rGO和掺杂石墨烯)以及石墨烯与生物分子、高分子、离子液体、金属或金属氧化物纳米粒子等复合材料修饰电极在检测各种生物分子方面的研究进展,并对该研究领域进行了展望.     

液相剥离石墨烯的电化学传感应用

石墨烯是一种新型二维碳材料,其比表面积大、导电性好、催化活性高、吸附能力强,是构筑高性能电化学传感器的理想材料.相对于石墨烯常用的氧化还原制备方法而言,液相剥离法具有过程简单、可控性强、高效环保以及对石墨烯结构破坏小等特点,在电化学传感领域备受关注.基于本课题组及国内外学者近年来的相关工作,本文重点综述了三种液相剥离石...     

鞣酸功能化石墨烯修饰电极上芦丁的电化学行为及灵敏检测

以双功能化试剂鞣酸一步还原法制备了鞣酸功能化的石墨烯纳米材料(TA-G)。鞣酸不仅起到还原剂的作用,还用作功能化试剂包裹石墨烯纳米片。将所制备的TA-G用于构建芦丁电化学传感器,可实现电化学信号放大并获得较好的检测灵敏度。电极反应动力学结果表明,芦丁在该修饰电极的电化学行为受表面准可逆过程控制。优化后的实验条件为p H 3.0,TA-G(1.0μg/m L)的电极修饰量为8μL,扫速为100m V/s,富集圈数为100圈。在优化条件下,芦丁的还原峰电流在1.0×10-8~1.0×10-5mol·L-1浓度范围内呈现良好的线性关系,检出限(S/N=3)为6.0×10-9mol/L。该传感器具有较高的稳定性、选择性和特异性,可实现实际样品中芦丁的灵敏检测,从而拓宽了石墨烯的应用领域并为药物的快速检测提供了新思路。     

石墨烯基微电极的制备及其在电化学传感中的应用

微电极由于灵敏度高、响应快、样品用量少、操作简便等特点,近年来在化学分析、生物医学、食品安全、环境检测等领域引起人们的广泛关注。 石墨烯具有超高的比表面积、优异的电子迁移率及良好的生物相容性等优点,近年来在电化学传感领域展示出巨大的发展前景。 本文围绕石墨烯基微电极的制备及其在电化学传感中的应用展开,总结了近年来国内外同行基于石墨烯修饰微电极和石墨烯微电极在重金属离子、多巴胺、葡萄糖、H₂O₂等分子检测方面取得的研究成果。 同时探讨了石墨烯基微电极在电化学传感方面面临的挑战和发展前景。     

功能化石墨烯负载冬凌草甲素抗肿瘤制剂的研究

通过改进的Hummers法制备氧化石墨烯(GO),利用酰胺化反应将端基为氨基的六臂聚乙二醇(PEG)连到氧化石墨烯表面,改善其水溶性和生物相容性.原子力显微镜(AFM)数据表明所制备的GO-PEG尺寸小于250 nm,稳定性试验证明GO-PEG在水和PBS缓冲液中可以很好地分散.利用制备的GO-PEG作为药物载体,通过物理共混的方法负载疏水性抗肿瘤药物——冬凌草甲素.紫外光谱法测得载药率高达105%,远高于一般其他的药物载体.选择肺癌细胞A549和乳腺癌细胞MCF-7对载药体系的细胞毒性进行了研究,结果表明即使在高达100 mg/L的浓度下培养48 h,载体GO-PEG对两种细胞仍然具有很小的毒性(相对细胞存活率>85%),而通过载体负载后冬凌草甲素的疗效有所增强,对细胞具有更大的杀伤作用.     

铁酞菁/氮掺杂石墨烯复合物的电化学传感研究

本文用快速简便的方法制备了铁酞菁/氮掺杂石墨烯（FePc/N-G）修饰电极,用于定量检测半胱氨酸. 采用电化学方法对修饰电极的性能进行了表征,结果表明氮掺杂石墨烯负载铁酞菁修饰电极对半胱氨酸具有更宽的线性响应范围和较高的灵敏度.     

甲基功能化Cd基金属有机骨架高灵敏电化学传感多巴胺

设计并合成了Cd基金属有机骨架(MOF)[Cd (BDC)(BPZ)(H₂O)]_n(1),其中BPZ=3,3′,5,5′-四甲基-1H,1′H-4,4′-联吡唑,H₂BDC=对苯二甲酸)。化合物1具有三维孔道,其孔壁内有多个—CH₃基团和自由的羧基氧原子,甲基基团的存在显著提高了MOF的疏水性和稳定性。另外,甲基和未配位的羧基氧原子可通过氢键或范德瓦耳斯作用力增强与多巴胺(DA)分子作用。1对DA具有灵敏的电化学传感性能。制备的1/GCE电极的差分脉冲伏安(DPV)测试结果显示其检测DA的线性范围为0.4~764.7 μmol·L^-1,检出限为56.8 nmol·L^-1。在常见干扰物的存在下,电极的DPV响应电流无明显变化。电极用于实际样品检测时的回收率在95.23%~100.90%之间。     

甲基功能化Cd基金属有机骨架高灵敏电化学传感多巴胺

设计并合成了 Cd 基金属有机骨架(MOF)[Cd(BDC)(BPZ)(H₂O)]_n (1),其中 BPZ=3,3'',5,5''-四甲基-1H,1''H-4,4''-联吡唑,H₂BDC=对苯二甲酸)。化合物1具有三维孔道,其孔壁内有多个-CH₃基团和自由的羧基氧原子,甲基基团的存在显著提高了MOF的疏水性和稳定性。另外,甲基和未配位的羧基氧原子可通过氢键或范德瓦耳斯作用力增强与多巴胺(DA)分子作用。1对 DA 具有灵敏的电化学传感性能。制备的 1/GCE 电极的差分脉冲伏安(DPV)测试结果显示其检测 DA 的线性范围为 0.4~764.7 μmol·L^-1,检出限为56.8 nmol·L^-1。在常见干扰物的存在下,电极的DPV响应电流无明显变化。电极用于实际样品检测时的回收率在95.23%~100.90%之间。     

Electrochemical Sensor for Sensitive Determination of Capsaicin Using Pd Decorated Reduced Graphene Oxide

In this work, the reduced graphene oxide functionalized with poly dimethyl diallyl ammonium chloride (PDDA) modified palladium nanoparticles (PDDA‐rGO/Pd) had been facile synthesized and used as the sensing layer for sensitive determination of capsaicin. The prepared composite was characterized by transmission electron microscopy, UV‐visible absorption spectroscopy. The image demonstrated that Pd nanoparticles were uniformly distributed on the graphene surface. The electrochemical properties of the prepared sensor were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the nanocomposite exhibits attractive electrocatalytic activity towards the oxidation of capsaicin. This attributed to the synergistic action of the excellent properties of Pd nanoparticles and graphene nanosheets. Under optimized conditions, the electrochemical sensor possessed a dynamic linear range from 0.32 μM to 64 μM with a detection limit of 0.10 μM (S/N=3) for capsaicin detection. Moreover, the cost‐effective and simple fabrication procedure, good reproducibility and stability as well as acceptable accuracy for capsaicin determination in actual samples are also the main advantages of this method, which might have broad application in other amide alkaloid detection.     

Synthesis of Zinc Tetraaminophthalocyanine Functionalized Graphene Nanosheets as an Enhanced Material for Sensitive Electrochemical Determination of Uric Acid

A new electrochemical sensor material has been fabricated via the non‐covalent functionalization of reduced graphene oxide (rGO) and soluble tetramino zincphthalocyanines (ZnPc‐NH₂). Immobilization of uricase onto the synthesized nanohybrids can evidently improve the electrocatalytic activity and selectivity. The obtained composite membrane possesses a great enhancement of electron transfer rate and excellent synergistic electrocatalytic effect toward uric acid (UA) oxidation under the working potential at 0.620 V vs. Ag/AgCl with a scan rate of 0.125 V/s. The effects of the experimental parameters on the electrochemical oxidation responses of UA were investigated and optimized in detail. Under the optimized conditions, the peak currents were proportional to the UA concentration in a range from 0.5 to 100 μmol/L with detection limit of 0.15 μmol/L. Moreover, the developed sensor was applied for UA determination in human urine samples with high accuracy and satisfactory recovery, which is envisioned to have promising applications in monitoring UA in clinical research.     

石墨烯量子点印迹传感器检测盐酸罗哌卡因

采用热聚合法合成石墨烯量子点,再将石墨烯量子点通过π-π作用吸附在聚邻氨基苯酚膜表面,基于石墨烯量子点表面电化学印迹,制备石墨烯量子点-分子印迹传感器检测盐酸罗哌卡因。同时采用原子力显微镜表征石墨烯量子点尺寸,示差脉冲伏安法研究印迹响应机理。安培I~t曲线法发现传感器对盐酸罗哌卡因的响应线性范围为2.0×10-6~6.1×10-4mol/L,检出限(S/N=3)为1.1×10-6mol/L,与未使用石墨烯量子点的分子印迹传感器对比,石墨烯量子点-分子印迹传感器的线性范围变宽,检出限降低,空白加标回收率为91.0%~101%。将传感器用于血浆样品中盐酸罗哌卡因的检测,测得其浓度为4.21×10-6mol/L,高效液相色谱法验证显示该方法的检测结果可靠,可用于临床样品的检测。     

Sensitive and Green Method for Determination of Chemical Oxygen Demand Using a Nano‐copper Based Electrochemical Sensor

Copper nanoparticles (nano‐Cu) were electrodeposited on the surface of glassy carbon electrode (GCE) potentiostatically at −0.6 V vs. Ag/AgCl for 60 s. The developed nano‐copper modified glassy carbon electrode (nano‐Cu/GCE) was optimized and utilized for electrochemical assay of chemical oxygen demand (COD) using glycine as a standard. The surface morphology and chemical composition of nano‐Cu/GCE were investigated using scanning electron microscope (SEM) and energy dispersive X‐ray spectrometer (EDX), respectively. The electrochemical behavior was investigated using linear sweep voltammetry (LSV) which is characterized by a remarkable anodic peak at ∼0.6 V, compared to bare GCE. This indicates that nano‐Cu enhances significantly the electrochemical oxidation of glycine. The effect of different deposition parameters, such as Cu²⁺ concentration, deposition potential, deposition time, pH, and scan rate on the response of the developed sensor were investigated. The optimized nano‐Cu/GCE based COD sensor exhibited a linear range of 15 to 629.3 ppm, and a lower limit of detection (LOD) of 1.7 ppm (S/N=3). This developed method exhibited high tolerance level to chloride ion (0.35 M chloride ion has minimal influence). The analytical utility of the prepared COD sensor was demonstrated by investigating the COD recovery (99.8±4.3) and the assay of COD in different water samples. The results obtained were verified using the standard dichromate method.     

基于Nafion固定磷钼酸和石墨烯共修饰PEDOT膜电极的电化学过氧化氢传感器

以玻碳电极（GCE）为基底电化学聚合制得聚3,4-乙烯二氧噻吩（PEDOT）膜修饰电极,再通过Nafion共固定磷钼酸和石墨烯构建了一种新型的无酶电化学H₂O₂传感器. 利用扫描电子显微镜（SEM）表征制得的修饰电极,并通过循环伏安法和计时电流法研究了传感器对H₂O₂的响应性能. 结果表明,在优化条件下,该传感器对H₂O₂还原具有良好的电催化性能,检测H₂O₂的线性范围为2.91×10^-6 ~ 1.83×10^-2 mol•L^-1,检出限和灵敏度分别为9.90×10^-7 mol•L^-1（S/N = 3）和112.5 μA•（mmol•L^-1）^-1. 此外,该传感器还具有良好的重现性和选择性.     

石墨烯修饰电极分子印迹电化学传感器的研制及其对多巴胺的测定

以石墨烯为电极增敏材料,多巴胺印迹聚合物为特异性识别材料,采用滴涂法组装石墨烯修饰电极的分子印迹电化学传感器。考察了pH值、石墨烯浓度、印迹聚合物浓度对传感器的影响,优化的实验条件为:pH 7.0,石墨烯浓度为0.5g/L,印迹聚合物浓度为20g/L。实验表明,该印迹传感器对多巴胺的响应电流远大于非印迹电极,同时该印迹传感器对多巴胺具有较好的选择性,检测范围为2.0×10-7～1.0×10-4mol/L,检出限(S/N=3)为6.8×10-8mol/L。该传感器用于盐酸多巴胺注射液的测定,其回收率为98%～105%。     

基于Au NPs@NU-901电化学传感器检测饼干中丁基羟基茴香醚的研究

基于金属有机骨架的拓扑三维结构的高比表面积以及金纳米颗粒(Au NPS)的优异电催化活性,金纳米颗粒与金属有机框架的复合材料在电化学传感领域拥有应用潜力.该文成功合成了Au NPs@NU-901复合材料,并采用透射电镜、X射线衍射、红外光谱以及X射线光电子能谱对其进行表征.采用线性扫描伏安法和差分脉冲伏安法研究了复合材...     

Fabrication of Electrochemical Sensor Modified with Porous Graphene for Determination of Trace Calycosin

In this study, the porous graphene (PG) with excellent structure was successfully prepared by a simple pyrolysis process, and applied to construct electrochemical sensor (PG@GCE) for detection of calycosin (CYS). PG was characterized by Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Also, the electrochemical properties of the proposed sensors were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the results indicated that sensors had relatively large specific surface area and higher electron transport rate. Based on all those characteristics, CYS, a traditional Chinese medicine (TCM) active ingredient, displayed a great response on the surface of PC@GCE. Under the optimized conditions, the sensors displayed a good linear relationship between the peak current and the CYS concentration in the range of 1.8 × 10^–7–4.4 × 10^–5 M with the detection limit of 5.8 × 10^–8 M (S/N = 3). This study provided a novel analytical method for detection of CYS, rapid identification of Radix Hedysari and Radix Astragali, and gave another way for the trace analysis of CYS in biological samples. Furthermore, it would also deepen the application of PG in the field of pharmaceutical analysis.     

基于银纳米粒子/氧化石墨烯复合薄膜制备TNP电化学传感器

利用改进的Hummers法制备了氧化石墨烯(GO), 以葡萄糖为还原剂直接在GO表面沉积银纳米粒子(AgNPs)得到性能稳定的AgNPs/GO纳米复合材料;基于该纳米复合材料修饰电极构建了一种新型的2, 4, 6-三硝基苯酚(TNP)电化学传感器。采用原子力显微镜(AFM)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见光谱(UV-Vis)和交流阻抗(EIS)等多种方法对纳米复合薄膜进行了表征;并研究了TNP在复合薄膜修饰电极上的电化学行为和动力学性质。结果表明, AgNPs/GO对TNP有较强的电催化活性, 在复合薄膜修饰电极出现一灵敏的氧化峰和3个还原峰;利用氧化峰可对TNP进行定量分析。同时整个电极过程明显不可逆, 电极反应受到吸附步骤控制;复合膜电极表面覆盖度为5.617×10^-8 mol·cm^-2, 在所研究电位下的速率常数为9.745×10^-5 cm·s^-1。在pH 6.8的磷酸缓冲液中, 当富集电位为-0.70 V, 富集时间为60 s;TNP氧化峰电流与其浓度在5.0×10^-9~1.0×10^-7 mol·L^-1范围内成良好线性关系, 相关系数为0.995 8, 检出限可达1.0×10^-9 mol·L^-1。所制备的电化学传感器稳定性和选择性较好;用于实际水样中TNP的现场快速检测, 加标回收率在 97.6%~103.9%之间。     

磁性石墨烯修饰辛基酚印迹传感器制备及应用研究

以辛基酚(4-OP)为模板分子,多巴胺为功能单体,采用电聚合技术在磁性石墨烯修饰碳电极表面制备对辛基酚具有高选择性与灵敏性的印迹电化学传感器。采用循环伏安法(CV)和差分脉冲伏安法(DPV)对此印迹传感器的电化学性能进行详细表征;采用扫描电子显微技术对修饰电极的形貌进行表征。结果表明,此印迹电化学传感器对辛基酚具有良好的特异识别性能。采用 DPV 法考察了孵化时间和洗脱溶剂对印迹传感器性能影响,结果表明,最佳孵化时间为14 min。此印迹电化学传感器的响应电流(△IR )与辛基酚在5.0×10-6~5.0×10-9 mol/ L 范围内浓度的负对数(-lgC)呈良好的线性关系,线性方程为△IR ( mA)=-0.25lgC(mol/ L)+2.35,检出限为3.64×10-10 mol/ L (S/ N=3)。此印迹电化学传感器对辛基酚具有良好的选择性和灵敏性,成功用于实际水样中辛基酚的检测,回收率为96.0%~104.0%。