以高氯酸·三-2,2′-联吡啶合钴(Ⅲ)为介体的葡萄糖氧化酶传感器的研究

以聚乙烯醇缩丁醛为固定葡萄糖氧化酶 (GOD)的载体 ,将GOD附在铂丝电极上并采用高氯酸·三_2,2′_联吡啶合钴(Ⅲ)[Co(bpy)3(ClO4)3]作为电子媒介体制得了电流型葡萄糖酶电极。讨论了溶解性媒介体Co(bpy)3(ClO4)3 的浓度、溶液的 pH值和温度对该电极电流响应的影响。该介体型葡萄糖传感器在优化的实验条件下 ,对葡萄糖表现出良好的响应特性 ,如响应快、重复性和稳定性好 ,传感器线性范围为6.0×10 -6～1.1×10 -4mol/L ,检出限为3.0×10 -6mol/L。将该电极用于人血清中葡萄糖测定 ,其结果与传统方法测得的结果一致。     

以高氯酸·三-2,2''''-联吡啶合钴(Ⅲ)为介体的葡萄糖氧化酶传感器的研究

以聚乙烯醇缩丁醛为固定葡萄糖氧化酶(GOD)的载体,将GOD附在铂丝电极上并采用高氯酸·三-2,2'-联吡啶合钴(Ⅲ)[Co(bpy)3(ClO4)3]作为电子媒介体制得了电流型葡萄糖酶电极.讨论了溶解性媒介体Co(bpy)3(ClO4)3的浓度、溶液的pH值和温度对该电极电流响应的影响.该介体型葡萄糖传感器在优化的实验条件下,对葡萄糖表现出良好的响应特性,如响应快、重复性和稳定性好,传感器线性范围为6.0×10-6～1.1×10-4mol/L,检出限为3.0×10-6mol/L.将该电极用于人血清中葡萄糖测定,其结果与传统方法测得的结果一致.     

六氟磷酸二(2,2′-联吡啶)(2,2′-联吡啶-4,4′-二羧酸)合钌(Ⅱ)的二维核磁共振谱分析

利用核磁共振氢谱和碳谱研究了电化学探针六氟磷酸二(2,2′-联吡啶)(2,2′-联吡啶-4,4'-二羧酸)合钌(Ⅱ)的立体结构,并通过二维1H-1H同核相关及1H-13C异核相关技术对其氢谱和碳谱进行了归属.     

天青Ⅰ为电子媒介体金纳米颗粒修饰葡萄糖生物传感器

用纳米金溶胶与聚乙烯醇缩丁醛(PVB)构成复合固酶基质,采用溶胶凝胶法固定葡萄糖氧化酶(GOx)于铂金电极表面,并在葡萄糖溶液中加入天青Ⅰ作为电子媒介体,制成了新型葡萄糖生物传感器。实验证明,葡萄糖氧化酶吸附在纳米金颗粒表面上稳定且保持其生物活性;而电子媒介体的存在,显著提高了传感器的响应灵敏度。该传感器对葡萄糖响应的线性范围为2.5×10-5～7.5×10-3mol/L;检出限为8.5×10-6mol/L(S/N=3)。该生物传感器用于人体血清中的葡萄糖测定,结果令人满意。     

电化学和紫外光谱研究In(Ⅲ)与2,2′-联吡啶的相互作用

在HAc-NaAc(pH=4.0)缓冲溶液中,用循环伏安法(CV)、交流阻抗法(EIS)、紫外光谱和紫外差光谱研究了In(Ⅲ)与2,2′—联吡啶(bpy)的相互作用。结果表明:In(Ⅲ)离子的循环伏安图呈现一对准可逆的氧化还原波,bpy与In(Ⅲ)作用后,In(Ⅲ)的氧化还原峰电流明显降低、式量电位正移,扩散系数减小,电化学反应阻抗增大;In(Ⅲ)与bpy作用后,bpy的紫外光谱发生了明显变化,紫外差光谱表明In(Ⅲ)与bpy结合比为1:2。     

纳米金胶增强葡萄糖生物传感器的构建

将纳米金胶(AuNPs)和羟基磷灰石(HAp)按一定比例混合制备了新型复合膜用于葡萄糖氧化酶(GOD)的固定,构建了高灵敏的葡萄糖传感器。由于纳米金胶的存在,葡萄糖氧化酶的直接电化学性质得以增强,在去除氧气的PBS(pH 7.0)介质中,固定在复合膜内的GOD表现出一对良好的氧化还原峰。在饱和氧气条件下,当加入一定量的葡萄糖时,由于GOD催化葡萄糖氧化消耗溶液中的溶解氧,-0.8 V处溶解氧的还原峰电流降低,且峰电流降低的量与葡萄糖浓度在0.02～1.62 mmol/L范围内呈线性相关,检出限为5.0μmol/L,检测灵敏度达9.91 mA.mol-1.L,可实现对葡萄糖的快速检测。     

以天青Ⅰ为介体的纳米金颗粒增强的葡萄糖传感器

采用层层自组装的方法和异种电荷互相吸引的原理,将Nafion修饰在金电极上固载带正电荷的天青Ⅰ,并利用天青Ⅰ中的氨基固载纳米金,再通过纳米金将酶固定在金电极表面,制成了葡萄糖传感器.采用循环伏安法和交流阻抗法,研究了金电极表面组装各层之后的电化学特征,以及电极对葡萄糖的电化学催化作用. 结果表明,天青Ⅰ不仅可以固定酶和纳米金,而且还可以在酶和电极之间有效地传递电子.在优化的实验条件下,该传感器对葡萄糖响应的线性范围为5.1×10-6 ~4.0×10-3 mol/L,检出限(S/N=3)为1.0 μmol/L.该生物传感器显示出较好的稳定性和抗干扰能力,将其用于人体血清中葡萄糖的测定,结果令人满意.     

三氯化六氨合钴(Ⅲ)合成条件的改进

在无机化学实验"三氯化六氨合钴(Ⅲ)的制备及组分测定"中,产物合成产率较低,影响后续实验开展和教学效果。本文基于基本化学原理优化实验合成条件,考查了活性炭催化剂用量、粒度和盐酸用量对三氯化六氨合钴(Ⅲ)产率的影响。实验结果表明:当活性炭催化剂用量为0.2 g、粒度为120目、盐酸溶液为(25 mL热水+1 mL盐酸)、浓盐酸用量为3 mL时,三氯化六氨合钴(Ⅲ)产率可达到42.5%,产品颜色(橙色)、纯度和结晶度明显提高,达到了实验预期结果。并且对不同粒度的催化剂,确定了可靠活性炭用量。通过该实验提高了学生化学基本原理的应用能力和解决问题能力。     

两个基于2,2′-联吡啶-3,3′-二羧酸的稀土配合物的晶体结构和荧光性质(英文)

采用水热法合成了2个具有二维结构的吡啶羧酸类稀土配位聚合物{[Ln2(bpdc)3(H2O)2]·5H2O}n,(Ln=Nd(1),Eu(2);bpdc=2,2′-Bipyridyl-3,3′-dicarboxylic acid)。单晶衍射分析显示1、2结构相似,均属于单斜晶系,P2/c空间群。1、2的晶胞参数分别为a=1.241 00(19)nm,b=0.748 35(59)nm,c=2.060 50(20)nm,β=94.84(1)°;a=1.241 00(19)nm,b=0.743 01(20)nm,c=2.052 50(30)nm,β=94.95(2)°。配合物是由之字形一维链构成的二维网络结构,其拓扑符号为{3^9;4^18;5}。热重测试结果表明1、2热稳定性较好。配合物2显示出很好的荧光性能。     

4′-苯基-2,2′∶6′,2″-三联吡啶镍配合物的合成与晶体结构

运用水热法合成了1个新的配合物[Ni(Phtpy)2](CH3COO)2(化合物1),(Phtpy=4′-苯基-2,2′∶6′,2″-三联吡啶),并通过X-射线单晶衍射方法确定了该化合物的晶体结构.结构分析表明化合物1属于三斜晶系,P-1空间群,晶胞参数a=0.905 60(8)nm,b=1.103 07(9)nm,c=2.020 14(15)nm,α=94.383 0(10)°,β=100.983 0(10)°,γ=106.312 0(10)°,V=1.883 1(3)nm3,Z=2,R1=0.087 2,wR2=0.183 1.配合物中存在3种氢键和多种π-π相互作用,使其成为一个3D配合物.     

Fiber-optic glucose biosensor based on glucose oxidase immobilised in a silica gel matrix

A monolithic silica gel matrix with entrapped glucose oxidase was constructed as a bioactive element in an optical biosensor for glucose determination. Physicochemical and biochemical characterizations of the catalytic matrix were performed, and the intrinsic fluorescence of immobilised glucose oxidase (GOD) was investigated in the UV and visible range by performing steady state and time course measurements. In all cases, the silica gel matrix proved to be a suitable support for optical biosensing owing to its superior optical properties (e.g., high transmittance and reliable fluorescence and GOD absorption spectra after immobilisation). From steady state measurements, calibration curves were obtained as a function of glucose concentration. When time course measurements were performed, the silica gel support displayed a larger linear calibration range and higher sensitivity than other immobilisation systems. In addition, a glucose optical biosensor was developed and characterised using as catalytic element GOD immobilised on a gel disk bound to a bundle of optical fibres.     

Amperometric glucose biosensor based on a gold nanorods/cellulose acetate composite film as immobilization matrix

We report on the utilization of gold nanorods to create a highly responsive glucose biosensor. The feasibility of an amperometric glucose biosensor based on immobilization of glucose oxidase (GOx) in gold nanorod is investigated. GOx is simply mixed with gold nanorods and cross-linked with a cellulose acetate (CA) medium by glutaraldehyde. The adsorption of GOx on the gold nanorods is confirmed by X-ray photoelectron spectroscopy (XPS) measurements. Circular dichroism (CD) and UV-spectrum results show that the activity of GOx was preserved after conjugating with gold nanorods. The current response of modified electrode is 10 times higher than that of without gold nanorods. Under optimal conditions, the biosensor shows high sensitivity (8.4 μA cm⁻² mM⁻¹), low detection limit (2 × 10⁻⁵ M), good storage stability and high affinity to glucose (). A linear calibration plot is obtained in the wide concentration range from 3 × 10⁻⁵ to 2.2 × 10⁻³ M.     

A sensitive immunosensor using colloidal gold as electrochemical label

A sensitive immunosensor using colloidal gold as electrochemical label is described. In this method, the capture protein was first immobilized on a carbon paste electrode surface through passive adsorption to bind quantitatively with corresponding antigen and colloidal gold labeled antibody to perform a sandwich assay. To detect the amount of the colloidal gold captured on the electrode surface, the colloid was first oxidized electrochemically to produce AuCl₄⁻ ions which were adsorbed strongly on the electrode surface. Adsorptive voltammetry was then employed for the determination of the adsorbed AuCl₄⁻ ions. A linear relationship between reduction wave peak current and the antigen concentration (human IgG) from 10 to 500 ng/ml is obtained with a detection limit of 4.0 ng/ml.     

A novel amperometric biosensor based on NiO hollow nanospheres for biosensing glucose

NiO hollow nanospheres were synthesized by controlled precipitation of metal ions with urea using carbon microspheres as templates, which were for the first time adopted to construct a novel amperometric glucose biosensor. Glucose oxidase was immobilized on the surface of hollow nanospheres through chitosan-assisted cross-linking technique. Due to the high specific active sites and high electrocatalytic activity of NiO hollow nanospheres, the constructed glucose biosensors exhibited a high sensitivity of 3.43 μA/mM. The low detection limit was estimated to be 47 μM (S/N = 3), and the Michaelis-Menten constant was found to be 7.76 mM, indicating the high affinity of enzyme on NiO hollow nanospheres to glucose. These results show that the NiO hollow nanospheres are a promising material to construct enzyme biosensors.     

Glucose biosensors based on the immobilization of copper oxide and glucose oxidase within a carbon paste matrix

The performance of amperometric glucose biosensors based on the dispersion of glucose oxidase (GOx) and copper oxide within a classical carbon (graphite) paste composite is reported in this work. Copper oxide promotes an excellent electrocatalytic activity towards the oxidation and reduction of hydrogen peroxide, allowing a large decrease in the oxidation and reduction overpotentials, as well as an important enhancement of the corresponding currents. Therefore, it is possible to perform the glucose biosensing at low potentials where there is no interference even in large excess of ascorbic acid, uric acid or acetaminophen. The influence of the copper oxide and glucose oxidase content in the paste on the analytical performance of the bioelectrode is discussed. The resulting biosensor shows a fast response, a linear relationship between current and glucose concentration up to 1.35 × 10⁻² M (2.43 g L⁻¹) and a detection limit of 2.0 × 10⁻⁵ M. The effect of the presence of the enzyme in the composite material on the dispersion of the copper oxide particles is also discussed.     

Evaluation of an amperometric glucose biosensor based on a ruthenium complex mediator of low redox potential

An amperometric glucose ring-disk biosensor based on a ruthenium complex mediator of low redox potential was fabricated and evaluated. This thin-layer radial flow microsensor (10 μl) with ring-disk working electrode displayed remarkable amperometric sensitivity. For Ru₃(μ₃-O)(AcO)₆(Py)₃(ClO₄) (Ru-Py), a trinuclear oxo-acetate bridged cluster, a reversible redox curve of low redox potential and narrow potential window (redox potentials were −0.190 and −0.106 V versus Ag/AgCl wire, respectively) was observed, which is comparable to many reported mediators such as ferrocene derivatives and other ruthenium complexes. The glucose and hydrogen peroxide assays were carried out with this complex-modified electrode Ru-Py-HRP-GOx/Nafion. The sensitivity was obtained 24 nA (15.4 mA M⁻¹ cm⁻²) for 10 μM glucose and 126 nA (160 mA M⁻¹ cm⁻²) for 5 μM H₂O₂, respectively with a working potential at 0 V versus Ag/AgCl. Ascorbic acid was studied as interference to the glucose assay. The application of 0 V potential versus Ag/AgCl did not avoid the occurrence of the oxidation of ascorbic acid, however, the pre-coating of ascorbate oxidase on the disk part of the ring-disk working electrode efficiently pre-oxidized the ascorbic acid and hence eliminated its interference on the glucose response. The practical reliability was also evaluated by assaying the dialysate from the prefrontal cortex of Wistar rats.     

An optical glucose biosensor based on glucose oxidase immobilized on a swim bladder membrane

An optical glucose biosensor using a swim bladder membrane as an enzyme immobilization platform and an oxygen-sensitive membrane as an optical oxygen transducer has been developed. During the enzymatic reaction, glucose is oxidized by glucose oxidase with a concomitant consumption of dissolved oxygen resulting in an increase in the fluorescence intensity of the optical oxygen transducer. The fluorescence intensity is directly related to the glucose concentration. The effects of pH, temperature, buffer concentration, and selectivity have been studied in detail. The immobilized enzyme retained 80% of its initial activity after being kept for more than 10 months at 4°C. The glucose biosensor has been successfully applied to the determination of glucose content in human blood serum and urine samples. Martin M.F. Choi was on sabbatical leave at The University of North Carolina at Chapel Hill from July 2004 to July 2005.     

Development of glucose amperometric biosensor based on a novel attractive enzyme immobilization matrix: amino derivative of thiacalix[4]arene

Calixarenes and their derivatives may be a promising material for enzyme immobilization owing to their particular configuration, unique molecule recognition function and aggregation properties. In this paper, p-tert-butylthiacalix[4]arene tetra-amine (TC4TA) was first used as enzyme immobilization material. This attractive material was exploited for the mild immobilization of glucose oxidase (GOD) to develop glucose amperometric biosensor. GOD was strongly adsorbed on the TC4TA modified electrode to form TC4TA/GOD composite membrane. The adsorption mechanism was driven from the covalent bond between amino-group of TC4TA and carboxyl group of GOD and molecule recognition function of TC4TA. Amperometric detection of glucose was evaluated by holding the modified electrode at 0.60 V (versus SCE) to oxidize the hydrogen peroxide generated by the enzymatic reaction. The sensor (TC4TA/GOD) showed a relative fast response (response time was about 5 s), low detection limit (20 μM, S/N = 3), and high sensitivity (ca. 10.2 mA M⁻¹ cm⁻²) with a linear range of 0.08–10 mM of glucose, as well as a good operational and storage stability. In addition, optimization of the biosensor construction, the effects of the applied potential as well as common interfering compounds on the amperometric response of the sensor were investigated and discussed herein.     

Development of an amperometric glucose biosensor based on the immobilization of glucose oxidase in an ormosil-PVA matrix onto a Prussian Blue modified electrode

An amperometric glucose biosensor was developed based on the immobilization of glucose oxidase in the organically modified silicate (ormosil)-polyvinyl acetate (PVA) matrix onto a Prussian Blue (PB)-modified glassy carbon electrode. A higher stability PB-modified electrode was prepared by the electrochemical deposition of FeCl₃, K₃[Fe(CN)₆] and ethylenediamine tetraacetic acid (EDTA) under cyclic voltammetric (CV) conditions. The effects of the potential range of CV conditions, electrolyte cations, applied potential, pH, temperature and co-existing substances were investigated. The detection limit of the glucose biosensor was 8.1 μmol·L⁻¹ (S/N = 3) with a linear range from 20 μmol·L⁻¹ to 2 mmol·L⁻¹ (R = 0.9965). The biosensor presented a fast response and good selectivity. Additionally, excellent reproducibility and stability of the biosensor were observed. Supported by the National High Technical Development Project (863 project) Foundation (Grant No. 2006AA09Z160) and the National Natural Science Foundation of China (Grant No. 20775064)