Highly sensitive spectrophotometric determination of trace amounts of platinum(IV) with the molybdate-basic dyes-poly(vinyl alcohol) system

Three highly sensitive spectrophotometric methods for the determination of platinum(IV) have been developed, based on its colour reactions with molybdate and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol). Platinum(IV) reacts with molybdate and BD to form ion — association complexes of composition (BD)₂[Pt (MoO₄)₃]. The molar absorptivities are between 6.83 × 10⁵ and 9.51 × 10⁵ dm³mol^–1cm^–1, the highest value being found with nile blue. Suitable conditions for the reactions and the effects of foreign ions were investigated. The methods can be applied to the spectrophotometric determination of trace amounts of platinum(IV) in some catalysts and ores.     

Development of an Enzymeless/Mediatorless Glucose Sensor Using Ruthenium Oxide‐Prussian Blue Combinative Analogue

Presented in this work is the first step towards an enzymeless/mediatorless glucose sensor. We first observed remarkable electrocatalytic oxidation of glucose using combinative ruthenium oxide (RuOx)‐Prussian blue (PB) analogues (designated as mvRuOx‐RuCN, mv: mixed valent) at ca. 1.1 V (vs. Ag/AgCl) in acidic media (pH 2 Na₂SO₄/H₂SO₄). Individual RuOx and PB analogs failed to give any such catalytic response. A high ruthenium oxidation state (i.e., oxy/hydroxy‐Ru^VII, E°≈1.4 V vs. RHE), normally occurring in strong alkaline conditions at RuOx‐based electrodes, was electrogenerated and stabilized (without any conventional disproportionation reaction) in the mvRuOx‐RuCN matrix for glucose catalysis. Detail X‐ray photoelectron spectroscopic studies can fully support the observation. The catalyst was chemically modified onto a disposable screen‐printed carbon electrode and employed for the amperometric detection of glucose via flow injection analysis (FIA). This system has a linear detection range of 0.3–20 mM with a detection limit and sensitivity of 40 μM (S/N=3) and 6.2 μA/(mM cm²), respectively, for glucose. Further steps towards the elimination of interference and the extendibility to neutral pHs were addressed.     

普鲁士兰修饰碳黑微电极同时微分伏安法测定多巴胺和抗坏血酸

将含有1.0%普鲁士蓝的碳黑与固体石蜡按2.5∶1(质量比)混合后装入φ0.2mm的石英毛细管中,在其上端插入一铂丝并抛光后即制成普鲁士蓝修饰碳黑微电极.对多巴胺(DA)及抗坏血酸(VC)在此电极上的电化学行为及应用此电极测定两组分的最佳条件进行了研究,在定量测定中采用二次微分线性扫描伏安法.在最佳条件下,DA与VC的峰电流(i″p)分别与各自的浓度保持如下线性关系DA为4.0×10-6～8.0×10-4mol·L-1,VC为6.0×10-5～1.0×10-3mol·L-1;检出限(3σ)依次为2.0×10-6mol·L-1及1.0×10-5mol·L-1.应用此方法分析了3种含DA及VC的混合溶液,测得结果的相对标准偏差(n=8)依次小于2.0%及3.0%,回收率范围依次为96.5%～101.0%及95.0%～102.5%.     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

Interaction of the important species HNO and HFSO2 in the atmosphere: Theoretical study of the N?H and S?H blue‐shifted hydrogen bonds

Ab initio molecular orbital and density functional theory (DFT) in conjunction with different basis sets calculations were performed to study the N? H…O and S? H…O blue‐shifted H‐bonds in the HNO…HFSO₂ complex. The geometric structures, vibrational frequencies, and interaction energies were calculated by both standard and CP‐corrected methods. Natural bond orbital (NBO) analysis was used to investigate the origin of blue‐shifted H‐bonds, showing that the decrease in the σ*(N? H) and σ*(S? H) is due to the electron density redistribution effect. The structure reorganization effect on the blue‐shifted hydrogen bonds was discussed in detail. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

A Selective Cholesterol Biosensor Based on Composite Film Modified Electrode for Amperometric Detection

An amperometric cholesterol biosensor based on immobilization of cholesterol oxidase in a Prussian blue (PB)/polypyrrole (PPy) composite film on the surface of a glassy carbon electrode was fabricated. Hydrogen peroxide produced by the enzymatic reaction was catalytically reduced on the PB film electrode at 0 V with a sensitivity of 39 μA (mol/L)^?1. Cholesterol in the concentration range of 10^?5 ? 10^?4 mol/L was determined with a detection limit of 6 × 10^?7 mol/L by amperometric method. Normal coexisting compounds in the bio‐samples such as ascorbic acid and uric acid do not interfere with the determination. The excellent properties of the sensor in sensitivity and selectivity are attributed to the PB/PPy layer modified on the sensor.     

Protective properties of redox polymer film deposited on stainless steel

We propose a novel composite organic-inorganic coating in the form of a redox polymer film for protection of stainless steel against general corrosion in strong acid medium (2 M H₂SO₄). We utilize an anion exchange polymer, protonated poly(4-vinylpyridine), into which hexacyanoferrate anions have been introduced. Owing to the presence of Fe(CN)₆^3–/4– at the interface formed by the film and the steel, a sparingly soluble metal hexacyanoferrate (mostly Prussian blue, PB) is formed as an overcoating on the steels surface, presumably on the passive (metal oxide) layer. The redox polymer film on the steel seems to act as a composite three-dimensional bilayer-type coating in which hexacyanoferrate(III,II) anions (that are capable of effective charge storage) exist in the outer portions of the film, whereas the inner PB layer improves the systems overall adherence and stability. By analogy to a conducting polymer (e.g. polyaniline, polypyrrole), introduction of the redox polymer composite film leads to stabilization of the steel substrates potential within the passive range.Contribution to the 3rd Baltic Conference on Electrochemistry, Gdansk-Sobieszewo, Poland, 23–26 April 2003Dedicated to the memory of Harry B. Mark, Jr. (28 February 1934–3 March 2003)     

溶剂热法制备Ag/TiO2纳米材料及其光催化性能

以乙醇为溶剂, 钛酸四丁酯为前驱体, 用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂. 利用X射线衍射(XRD)、N₂吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征, 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了不同Ag含量样品的光催化性能. 结果表明: 用溶剂热法制备的样品中TiO₂皆为锐钛矿相, 金属Ag颗粒沉积在TiO₂表面, 粒径为2 nm左右, 比表面积较溶胶凝胶法制备的样品大大增加, 最高可达151.44 m²·g^-1; UV-Vis光谱和光催化实验表明: Ag修饰使TiO₂对光的吸收能力大大增强, 吸收带边红移至可见光区, 亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型; 溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品, 在紫外光和可见光下, Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

纳米尺寸聚苯乙烯-丙烯酸彩色高分子微球的合成与表征

以苯乙烯、丙烯酸、分散蓝染料为原料,采用分步聚合的方法合成了彩色具有核–壳结构的分散蓝/聚苯乙烯–丙烯酸高分子微球。通过TEM测得其颗粒尺寸约为200nm,分散均匀;通过FTIR对颗粒的组成结构进行表征,并对其合成过程进行探讨。