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葡萄糖氧化酶在石墨烯-纳米氧化锌修饰玻碳电极上的直接电化学及对葡萄糖的生物传感 总被引:1,自引:0,他引:1
采用滴涂法和电沉积法制备了石墨烯/纳米氧化锌复合膜修饰玻碳电极,再将葡萄糖氧化酶固定在修饰电极表面制成了电化学生物传感器,用于葡萄糖的灵敏测定。用循环伏安法在-0.7~-0.1 V范围内研究了葡萄糖氧化酶在修饰电极上的直接电化学行为。结果表明,石墨烯/纳米氧化锌复合膜能很好地保持葡萄糖氧化酶的生物活性,并显著促进了其电化学过程。在0.1 mol/L磷酸盐缓冲溶液(pH 7.0)中,固定在修饰电极上的葡萄糖氧化酶呈现出一对近乎可逆的氧化还原峰,并且对葡萄糖的氧化具有良好的催化作用。葡萄糖氧化酶在修饰电极上的电子转移常数ks为1.42 s-1,修饰电极对葡萄糖催化的米氏常数Kampp为14.2μmol/L。线性范围为2.5×10-6~1.5×10-3mol/L,检出限为2.4×10-7mol/L(S/N=3)。此修饰电极具有良好的导电性能、稳定性和重现性,可用于实际样品的分析测定。 相似文献
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用电化学方法研究了金胶表面固定酪氨酸酶(Tyr)的直接电子传递行为和该修饰电极在苯酚分析方面的应用。金胶联接在半胱胺自组装单层尾部的氨基上。在pH7.0的0.1 mol/L磷酸盐缓冲溶液中,Tyr/金胶/半胱胺修饰电极上的Tyr进行直接电子传递,产生一对氧化还原峰。固定在金胶表面的Tyr的表面覆盖度为6.6×10-10mol/cm2。不需要电子媒介体的作用,该传感器对苯酚的还原具有较好的电催化作用。苯酚测定的线性范围为2.5μmol/L~5 mmol/L,检出限为0.8μmol/L(信噪比是3)。该传感器对苯酚的测定显示了良好的重复性。在高浓度的苯酚中,此传感器表现出Michaelis-Menten行为,KMapp为3.8 mmol/L。 相似文献
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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。 相似文献
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利用Nafion(全氟聚苯乙烯磺酸溶液)-氧化石墨烯复合物、硫堇和纳米金构建了H2O2酶传感器。首先将氧化石墨烯分散在体积分数0.2%Nafion溶液中制得Nafion-氧化石墨烯的复合物,并将其固定在玻碳电极表面,通过静电吸附将带正电荷的硫堇吸附到Nafion-氧化石墨烯复合膜修饰的玻碳电极表面,再利用静电吸附将纳米金修饰于电极上,通过纳米金来固定辣根过氧化物酶从而制得H2O2传感器。用循环伏安法和计时电流法考察该修饰电极的电化学特性。H2O2浓度为5.5×10-6~1.0×10-3mol/L时,酶电极的响应电流值与H2O2的浓度呈良好的线性关系,检出限为1.80×10-6mol/L。 相似文献
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制备了石墨烯薄膜修饰玻碳电极,并通过循环伏安法研究了对硫磷(PT)在该修饰电极上的电化学行为。对支持电解质、溶液pH值等实验条件进行了优化。结果表明,在0.1mol/L的乙酸-乙酸钠缓冲溶液(pH=5.0)中,PT在石墨烯薄膜修饰电极上具有良好的电化学响应,对比裸玻碳电极,PT的氧化峰峰电流显著提高,表明修饰膜对PT的电化学氧化具有一定的催化作用。PT的氧化峰电流及其浓度分别在1.0×10-7~1.0×10-6 mol/L范围内和3.0×10-6~1.0×10-5 mol/L范围内呈良好的线性关系,线性相关系数分别是0.9956和0.9874,检出限为1.0×10-8 mol/L。将该修饰电极应用于小白菜中残留PT的测量,结果比较满意。 相似文献
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采用一步电化学共还原的方法将纳米金(AuNPs)、Nafion、电化学还原石墨烯(ERGO)修饰到玻碳电极(GCE)表面,制成修饰电极AuNPs/Nafion/ERGO/GCE。以扫描电镜对其进行表征,用循环伏安法和微分脉冲伏安法研究对苯二酚在该修饰电极上的电催化行为。优化了实验参数,对苯二酚在2.0~100μmol/L及100~800μmol/L浓度范围内与其氧化峰电流呈良好的线性关系,检出限为0.3μmol/L。用该修饰电极成功地进行了实际水样中对苯二酚含量的测定。 相似文献
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多环芳二酐型聚酯亚胺膜的透气性能李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚醚酰亚胺,聚酯酰亚胺,膜,透气性通常的聚酰亚胺加工性能较差,在芳环二酐的苯环间引入醚键等柔性基团后,其... 相似文献
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微量元素与疾病诊断治疗的研究现状及展望 总被引:8,自引:0,他引:8
对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述,包括:微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。 相似文献
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Wenbi Guan 《International journal of environmental analytical chemistry》2013,93(6):679-691
A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg?1, the maximum residue level of European Union for quizalofop-p-ethyl). 相似文献
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Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB5型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。 相似文献
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Prof. Inmaculada García‐Moreno Lu Wang Prof. Angel Costela Dr. Jorge Bañuelos Prof. Iñigo López Arbeloa Prof. Yi Xiao 《Chemphyschem》2012,13(17):3923-3931
Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission. 相似文献
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Peter Kis Eva Horvthov Elika Glov Andrea ev
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ov Veronika Antalov Elena Karniov Potock Vladimír Mastihuba Mria Mastihubov 《Molecules (Basel, Switzerland)》2021,26(24)
Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection. 相似文献
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The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R2UPh type and -thioureas of the R2TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments. 相似文献
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Charles Manzi-Nshuti 《Polymer Degradation and Stability》2007,92(10):1803-1812
In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer. 相似文献