废虾壳衍生多孔碳纳米酶的制备及用于比色检测自来水中过氧化氢

以废虾壳为碳源，通过惰性气氛高温碳化法制得废虾壳衍生的多孔碳纳米酶，并将其作为一种类过氧化物模拟酶用于比色检测自来水中的H₂O₂。所制备的碳纳米酶呈无定型多孔结构，且催化活性类似天然辣根过氧化物酶。考察了反应体系中各参数对类过氧化物酶催化活性的影响。在最优条件下，废虾壳衍生多孔碳纳米酶比色分析H₂O₂的线性范围为0～200μmol/L，线性相关系数R²=0.9772，检出限为0.59μmol/L。建立的方法可用于快速分析自来水中的H₂O₂。     

基于金属卟啉2DMOFs仿酶催化的过氧化氢比色法检测

以四（4-羧苯基）铁卟啉（FeTCPP）作为有机配体,铜离子作为金属节点,利用溶剂热法制备了双金属Cu-FeTCPP金属有机骨架（MOFs）材料,并采用表面活性剂辅助法合成了二维纳米片（Cu-FeTCPP 2DMOFs）.该纳米片呈超薄的纳米结构,与三维块体结构（3DMOFs）相比具有更大的比表面积.基于Cu-FeTCPP 2DMOFs的仿酶特性,将其用于催化过氧化氢（H₂O₂）氧化底物3,3',5,5'-四甲基联苯胺（TMB）显色,根据显色产物吸光度与H₂O₂浓度之间的正比关系实现了对H₂O₂的测定.经稳态动力学分析发现,底物相同时该纳米片的米氏常数K_m均比Cu-FeTCPP 3DMOFs的K_m小,表明纳米片与底物之间有更好的亲和力,这归因于二维结构大的比表面积和较多易接近的活性位点.基于Cu-FeTCPP 2DMOFs构建的比色检测方法在优化条件下对H₂O₂的线性检测范围为3~1000 μmol/L,检出限为2.08 μmol/L,在水体中H₂O₂的检测方面具有良好的应用前景.     

具有过氧化物酶活性的Imm-Fe3+-IL的制备及用于比色法测定H2O2和葡萄糖

通过溶胶-凝胶法制备的Imm-Fe³⁺-IL纳米材料具有类过氧化物酶的活性,能够催化过氧化氢(H₂O₂)快速氧化3,3′,5,5′-四甲基联苯胺(TMB)产生相应的颜色变化。 稳态动力学分析表明,Imm-Fe³⁺-IL纳米材料遵循典型的Michaelis-Menten模型和乒乓机理。 辣根过氧化物酶(HRP)相比,Imm-Fe³⁺-IL纳米材料纳米材料具有更强的亲和性。 联合葡萄糖氧化酶建立了H₂O₂和葡萄糖的比色检测方法。 结果显示:H₂O₂和葡萄糖的浓度与反应体系的吸光度呈良好的线性关系,H₂O₂的线性范围为1~200 μmol/L,葡萄糖的线性范围为10~200 μmol/L,最低检出限(LOD)分别为0.35和3.31 μmol/L。     

基于CoFe(Ⅲ)PBA/GO过氧化物模拟酶化学发光法检测H2O2和抗坏血酸

制备了一种具有过氧化物酶活性的类普鲁士蓝/氧化石墨烯复合纳米材料(CoFe(Ⅲ)PBA/GO)。将具有过氧化物酶活性的CoFe(Ⅲ)PBA/GO和化学发光法相结合,构建了一种用于检测H₂O₂和抗坏血酸(AA)的化学发光分析法。CoFe(Ⅲ)PBA/GO催化H₂O₂产生的O₂·^-,·OH,1O₂自由基氧化Luminol会产生很强的化学发光信号,通过检测化学发光强度可以实现对H₂O₂的检测。该方法检测H₂O₂的线性范围为0~0.8μmol/L,检测限为11 nmol/L。利用AA作为活性氧消除剂可以抑制化学发光反应的特点,实现了AA的检测。该方法测定AA的线性范围为0.02~0.8μmol/L,检测限为20 nmol/L。方法已应用于H₂O₂消毒水中H₂O₂和维生素C片中抗坏血酸的检测。     

基于次血红素六肽的过氧化氢和葡萄糖灵敏比色方法

采用次血红素六肽(DhHP-6)催化H₂O₂氧化4-氨基安替吡啉-氯代苯酚显色体系,建立了测定H₂O₂和葡萄糖的方法。 研究了pH值、底物浓度和DhHP-6浓度对实验的影响,检测了比色方法的反应线性、稳定性、相关性和回收率。 在最佳反应条件下,DhHP-6在不同时间及温度条件下,活性要优于过氧化物酶(POD);DhHP-6催化H₂O₂ 的米氏常数(K_m)和最大反应速率(v_max)分别为0.171 mmo/L和4.22×10^-6 mol/s;H₂O₂响应的线性范围为0.39~25.0 mmol/L;高、中、低 3水平测定的变异系数(CV)和加标回收率分别在1.29%~2.16%和94.5%~101.1%之间;与葡萄糖商品试剂盒比较相关系数R²=0.9946;36例血液样品中的葡萄糖浓度在4.26~17.48 mmol/L之间。 与葡萄糖检测商品试剂盒之间的两组数据经统计差异不显著(P>0.05)。 该方法是一种简单、廉价、方便、灵敏的比色测定方法。     

双功能碳点用于葡萄糖的比色/比率荧光测定

以生物质(合果芋叶片)、 十二水合硫酸铁铵和脲为原料, 采用水热法制备了铁、 氮共掺杂碳点(Fe,N-CDs), 采用透射电子显微镜和X射线光电子能谱对其形貌与元素组成进行了表征. 该Fe,N-CDs既具有类过氧化物酶活性, 也能在450 nm处产生强荧光发射. 以Fe,N-CDs和邻苯二胺(OPD)为探针, 建立了一种比色/比率荧光测定双氧水（H₂O₂）的双信号方法. 在H₂O₂存在下, Fe,N-CDs催化OPD氧化成黄色的2,3-二氨基吩嗪(DAP), DAP在420 nm处有1个特征吸收峰. 在360 nm波长光的激发下, DAP在550 nm处有强荧光发射; 由于荧光内滤效应, DAP又可猝灭Fe,N-CDs在450 nm处的荧光. 基于此, DAP在420 nm处的吸光度(A₄₂₀)及DAP与Fe,N-CDs的荧光强度比(I₅₅₀/I₄₅₀)均可用于H₂O₂的定量分析. 考虑到葡萄糖氧化酶能催化葡萄糖氧化生成H₂O₂, 进一步发展了一种比色/比率荧光双信号葡萄糖测定方法. 在pH=5.4, 温度40 ℃, 1.75 mmol/L OPD及反应时间25 min的条件下, 当葡萄糖浓度在1.0~100 μmol/L范围内时, A₄₂₀及I₅₅₀/I₄₅₀值与浓度呈良好的线性关系, 方法的检出限分别为0.8(比色)和0.6 μmol/L(比率荧光). 将该方法成功应用于人体血清中葡萄糖的测定.     

基于Fe7S8纳米酶的H2O2手机可视化比色检测

铁基纳米材料因具有丰富的化合价态和活性位点,表现出良好的类过氧化物酶活性而受到广泛关注。该研究通过简单水热法合成Fe₇S₈纳米花(NFs),并基于其类过氧化物酶活性构建了用于H₂O₂高灵敏度比色检测的3,3’,5,5’-四甲基联苯胺(TMB)和H₂O₂显色体系。优化了体系的显色条件,并考察了Fe₇S₈ NFs的类酶活性稳态动力学及催化机理。在0.001～9 mmol/L和9～70 mmol/L范围内,H₂O₂浓度与652 nm处的吸光度值呈现良好的线性关系,对应的检出限分别为0.33μmol/L和3 mmol/L。同时方法具有良好的抗干扰能力。通过结合拍照暗箱装置和色值分析软件(Thing Identify),实现了基于智能手机的H₂O₂可视化检测,并成功用于实际水样检测。开发的智能手机可视化比色检测方法具有操作简便、成本低等...     

氮、铁共掺杂碳纳米粒子的制备及在过氧化氢和葡萄糖检测中的应用

以L-酒石酸和一水柠檬酸为混合碳源,以乙二胺为氮源和聚合试剂,并添加六水三氯化铁,通过一锅溶剂热法合成了氮、铁共掺杂碳纳米粒子(N/Fe-CNPs),采用制备的N/Fe-CNPs模拟过氧化物酶催化过氧化氢(H₂O₂)氧化3,3',5,5'-四甲基 产生可溶性的蓝色产物,联合葡萄糖氧化酶建立了测定H₂O₂和葡萄糖含量的新方法。 结果显示:H₂O₂及葡萄糖的浓度与反应体系的吸光度呈良好的线性关系,H₂O₂的线性范围为0.2~20 μmol/L,葡萄糖的线性范围为0.1~1.0及1.0~80 μmol/L,最低检出限分别可达42.5和76.1 nmol/L。     

层状钒青铜纳米片的制备及其锂离子电池阳极材料性能

室温下, 在水溶液中将铵根离子和水分子插入到商用V₂O₅纳米颗粒的层间, 制得了层状的钒青 铜[(NH₄)₂V₆O₁₆·H₂O]纳米片. 该纳米片的尺寸为2~10 μm, 厚度为50~250 nm. 与商用V₂O₅纳米颗粒相比, (NH₄)₂V₆O₁₆·H₂O纳米片用作锂离子电池(LIBs)的阳极材料时, 其性能得到较大提升, 包括大的可逆放电容量 (0.1 A/g时为1148 mA·h/g)、 出色的循环性能(循环70圈后在0.1 A/g时具有1002 mA·h/g的高容量)和高倍率性能(在0.1 A/g时具有1070 mA·h/g的可逆性能). 研究结果表明, (NH₄)₂V₆O₁₆·H₂O纳米片可以作为锂离子电池优良的阳极材料, 也有望应用于其它(如钠离子电池和锌离子电池等)可再充电电池.     

自然水体生物膜体系中过氧化氢浓度的影响因素

以过氧化氢(H₂O₂)为自然水体生物膜产生的活性氧(ROS)的代表, 通过模拟实验, 研究了水-自然水体生物膜体系中光/暗变化、 生物膜的避光预处理与数量、 有机配体和pH值对体系中H₂O₂浓度的影响. 结果表明, 光照可快速增加体系中H₂O₂浓度, 光照转为无光时体系H₂O₂浓度下降(约为光照时的2/3); 避光预处理会显著降低体系中H₂O₂的产生速率和浓度; 生物膜数量的增减会导致体系H₂O₂浓度的相应增减; 有机配体的存在会使体系内H₂O₂浓度下降(约1/2~1/3); pH=7和5的体系中H₂O₂的浓度高于pH=9的体系(高出约1.5倍). 上述各因素主要通过影响生物膜生产H₂O₂、 H₂O₂自然分解和生物膜去除H₂O₂ 3种作用来影响体系H₂O₂浓度.     

氧化石墨烯/富勒烯复合材料增敏多金属离子印迹电化学传感器

制备了一种对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)等多金属离子具有灵敏、选择性响应的新型印迹传感器。 以甲基丙烯酸与乙二胺四乙酸分别为功能单体与配体,乙二醇二甲基丙烯酸酯为交联剂制备出多金属离子印迹聚合物。 采用滴涂法将离子印迹聚合物均匀地修饰至氧化石墨烯/富勒烯复合材料修饰碳电极表面,成功制备出灵敏的多金属离子印迹电化学传感器。 采取循环伏安法、交流阻抗和差分脉冲法等技术对印迹电化学传感器的性能进行表征,结果表明该多金属离子印迹电化学传感器具有良好的选择性。 在1.0×10^-9~5.0×10^-7 mol/L范围内,该多金属离子印迹电极的响应电流与金属离子浓度呈现良好的线性关系,对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)金属离子的最低检测限分别为5.0×10^-10、5.0×10^-10和1.0×10^-10 mol/L。 该多金属离子印迹电化学传感器成功用于实际样品中微量Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)等金属离子的检测。     

Immobilization of Hemoglobin on Cobalt Nanoparticles-modified Indium Tin Oxide Electrode:Direct Electrochemistry and Electrocatalytic Activity

A cobalt nanoparticles-attached indium tin oxide(CoNPs/ITO) electrode was applied to the immobilization of hemoglobin(Hb) and an Hb modified CoNPs/ITO electrode(Hb/CoNPs/ITO) was prepared. The direct electron transfer of Hb was shown by the well-behaved voltammetric responses for Hb/CoNPs/ITO electrode and the effects of scan rate and pH value were observed. Based on the catalytic activity of Hb immobilized on the CoNPs/ITO electrode toward the reduction of H₂O₂, a mediator-free H₂O₂ sensor was developed. A linear relationship existed between the catalytic current and the H₂O₂ concentration in a range of 1.0―100.0 μmol/L with a detection limit (S/N=3) of 0.2 μmol/L.     

Potentiometric determination of hydrogen peroxide at MnO2-doped carbon paste electrode

A novel hydrogen peroxide (H₂O₂) potentiometric sensor, made with a MnO₂-doped carbon paste electrode (CPE), is reported. Under optimum conditions, the electrode gives a Nernstian response for H₂O₂ in the concentration range 3.00×10⁻⁷–3.63×10⁻⁴ mol/l, with a slope of 21–19.4 mV/pH₂O₂ and a detection limit of 1.2×10⁻⁷mol/l H₂O₂. In addition, this sensor offers some analytical characteristics such as sensitivity, good reproducibility and a simple preparation procedure. The effects of both the components of the electrode and other conditions on the potential response of the sensor, as well as the possible response mechanism, are discussed.     

Platinum black coated microdisk electrodes for the determination of high concentrations of hydrogen peroxide in phosphate buffer solutions

The performance of a series of platinum black coated microdisk electrodes (Pt-Bs) was investigated in H₂O₂ solutions over the concentration range 0.1–500 mM, in phosphate buffer media pH 7. The Pt-Bs were prepared by electrodeposition of Pt onto the surface of microdisk electrodes 12.5 μm of nominal radius, from aqueous solutions containing hexachloroplatinic acid. The resulting roughness factors (RF, i.e., the ratio of the effective surface area to the geometric electrode area) varied between about 10 and 100. The voltammograms recorded with these electrodes, at relatively low H₂O₂ concentrations (up to 50–100 mM), displayed rather steep mixed anodic–cathodic waves, which attained well-defined and stable current plateaus. At the higher hydrogen peroxide concentrations, additional waves both in the anodic and cathodic region or dramatic current drop phenomena were observed. The wave split phenomenon was attributed to the insufficient buffering capacity of the base electrolyte solution within the pores of the platinum black, induced by the large amounts of hydrogen ions produced in the oxidation process. The current drop was attributed to either the formation of oxygen bubbles, which limit diffusion of H₂O₂ down the pores, or saturation of the active sites responsible for the decomposition of H₂O₂ to O₂ and H₂O. The H₂O₂ concentration at which the above phenomena occurred depended either on the phosphate buffer concentration in the bulk solution or the RF factor of the electrodes. The latter conditions also affected the dynamic range of detection, the sensitivity and low detection limits. Advantageous analytical characteristics were obtained with a Pt-B of RF of about 24, which provided a dynamic range between 0.5 and 230 mM, a sensitivity of 1.93(±0.06) A M⁻¹ cm⁻² and a low detection limit of 0.05 mM. The reproducibility was also very good, it being within 2–3%. The usefulness of the Pt-Bs for real samples analysis was tested in an antiseptic solution containing large amounts of H₂O₂.     

Self-assembling gold nanoparticles on thiol-functionalized poly(styrene-co-acrylic acid) nanospheres for fabrication of a mediatorless biosensor

A novel strategy to construct a sensitive mediatorless sensor of H₂O₂ was described. At first, a cleaned gold electrode was immersed in thiol-functionalized poly(styrene-co-acrylic acid) (St-co-AA) nanosphere latex prepared by emulsifier-free emulsion polymerization St with AA and function with dithioglycol to assemble the nanospheres, then gold nanoparticles were chemisorbed onto the thiol groups and formed monolayers on the surface of poly(St-co-AA) nanospheres. Finally, horseradish peroxidase (HRP) was immobilized on the surface of the gold nanoparticles. The sensor displayed an excellent electrocatalytical response to reduction of H₂O₂ without the aid of an electron mediator. The biosensor showed a linear range of 8.0 μmol L⁻¹–7.0 mmol L⁻¹ with a detection limit of 4.0 μmol L⁻¹. The biosensor retained more than 97.8% of its original activity after 60 days’ storage. Moreover, the studied biosensor exhibited good current reproducibility and good fabrication reproducibility.     

Fluorescent and colorimetric immunoassay of nuclear matrix protein 22 enhanced by porous Pd nanoparticles

A new modified ELISA enhanced by porous Pd nanoparticles for colorimetric and fluorescence dual-modal immunoassay of nuclear matrix protein 22 has been demonstrated. Benefited from different signalreadout and independent signal amplified mechanism, the improved ELISA will afford more reliable detection performance, which can bring high promising for clinical diagnosis.     

Spectrophotometric determination of hydrogen peroxide in rainwater

Hydrogen peroxide in rainwater has been determined from the measurement of absorption at 432 nm after the formation of the stable oxo-peroxo-pyridine-2,6-dicarboxylatovanadate(V) complex (OPDV) in acid media. Determinations were in good agreement with those using a modified p-hydroxyphenylacetic acid (PHPA) emission method. The linear range for the OPDV method is from 0.05 to 50 ppm H₂O₂, and the limit of detection under the analytical conditions employed was 5.8 nmol H₂O₂ for a 20 cm³ rainwater sample. The volume weighted mean H₂O₂ concentration in rainwater collected at roof-top level in central Kowloon was 15.9 μM (N=10), and the ratio of non-sea salt sulphate and H₂O₂ concentrations was significantly correlated with pH. The OPDV absorption method was also employed for the determination of ambient gaseous H₂O₂, and liquid-nitrogen cold-trap collection gave results about 30% lower than impinger sampling, where artifact H₂O₂ formation occurred.     

基于N,N'-双(3-吡啶基)-对苯二甲酰胺和1,3,5-苯三甲酸的二维Co(Ⅱ)金属有机骨架的合成、结构和磁性

在水热条件下,基于配体N,N'-双(3-吡啶基)-对苯二甲酰胺(3-bptpa)和1,3,5-苯三甲酸(1,3,5-H₃btc),合成了一例具有二维格子结构的钴(Ⅱ)MOF[Co(3-bptpa)(1,3,5-Hbtc)]·2H₂O(1),并进行了红外光谱(FT-IR)、元素分析(EDS)、差热-热重分析(DTA-TG)、X射线单晶衍射(XRD)和磁学表征。 结果表明,每个1,3,5-Hbtc^2-提供1个螯合配位羧基和1个桥连配位羧基与Co(Ⅱ)离子配位。 中心对称的二聚体[Co(3-bptpa)(1,3,5-Hbtc)]₂通过桥连配位的羧基连接成1D梯形链,相邻的梯形链通过3-bptpa与Co(Ⅱ)的配位作用连接为2D格子,从而形成CoN₂O₄变形八面体的配位构型。对配合物1在16~300 K的磁化率数据,使用八面体场下旋轨耦合的各向同性的单离子近似和分子场理论进行分析,Co(Ⅱ)离子表现强的旋轨耦合作用(λ=-100.4 cm^-1),相邻的Co(Ⅱ)离子之间通过桥连配位的羧基传递弱的反铁磁相互作用(zj'=-0.618 cm^-1)。