阻抑茜素红S褪色动力学光度法测定痕量汞

在HAc—NaAc介质中,以邻菲啰啉作活化剂,痕量Cr（Ⅵ）对H2O2氧化茜素红S褪色反应存在强烈的催化作用,而Hg（Ⅱ）对此褪色反应具有明显的阻抑作用,由此建立了测定痕量Hg（Ⅱ）的新阻抑动力学光度法。该方法线性范围为0～1．6μg／mL,检出限为2．6×10^-8g／mL,应用于污水中Hg（Ⅱ）的测定,结果满意。     

加替沙星-茜素红体系的紫外特性及加替沙星的测定

加替沙星与茜素红反应可形成配合物,使茜素红的紫外吸光度增强,且加替沙星浓度在0.20~110.00mg.L-1范围内与吸光度呈良好的线性关系,以此为基础,建立了测定加替沙星的新方法.将此方法用于片剂、粉针剂和尿液中加替沙星含量的测定,结果与文献报道的荧光法一致.     

Modification of carbon paste with congo red supported on multi-walled carbon nanotube for voltammetric determination of uric acid in the presence of ascorbic acid

A chemically modified carbon-paste electrode (CPE) is prepared by incorporating congo red (CR) immobilized on multi-walled carbon nanotube (MWCNT). The results show that CR is effectively immobilized on the surface of MWCNT under the ultrasonic agitation in aqueous solution and further incorporating the nafion. The prepared electrode, due to the electrostatic repulsions between the CR and ascorbate anion, is capable to mask the response of the ascorbic acid (AA) completely and provide an effective method for the detection of minor amounts of uric acid (UA) in the presence of high concentrations of AA. On the other hand, an increase in the microscopic area of the electrode by addition of MWCNT together with the electrocatalytic activity caused to a significant enhancement in the voltammetric response to UA. Optimization of the amounts of composite modifier in the matrix of CPE is performed by cyclic and differential pulse voltammetric measurements. The modified electrode shows a linear response to UA in the range of 1.0 × 10⁻⁷–1.0 × 10⁻⁴ M with a detection limit of 1.0 × 10⁻⁸ M. The electrode exhibits excellent accuracies for the determination of UA in the presence of high concentrations of AA (a recovery of 97.6%). The response of the electrode toward sulfhydryl compounds such as cysteine, penicillamine, and glutathione is not considerable. This reveals a good selectivity for the voltammetric response toward UA. The effective electrocatalytic property, ability for masking the voltammetric responses of the other biologically reducing agents, ease of preparation, and surface regeneration by simple polishing together with high reproducibility and stability of the responses make the modified electrode suitable for the selective and sensitive voltammetric detection of sub-micromolar amounts of UA in clinical and pharmaceutical preparations.     

Influence of Annealing on the Quantum Yield of Sensitized Phosphorescence of Naphthalene in Frozen Solutions of n-Hexane

We revealed and investigated the increase in the quantum yield of sensitized phosphorescence of naphthalene in a frozen solution of n-hexane as a result of annealing of a specimen near the melting point of a solvent. We show that the reason for the rise in the quantum yield is the increase in the number of acceptor molecules that participate in radiation due to the removal of static quenching.     

A Highly Sensitive Kinetic Spectrophotometric System and Its Analytical Potential for Chromatographic Detection of Metal Ions

Micelles,microemulsions.vesicles,etc.,areorganicmicroheterogeneousmedia.Useofthesemediainanalyticalreactionsfordevelopingnewkinetic-baseddeterminationsorimprovingpreviouslyestablishedkineticmethodshasbeenreported"2.Inrecentyears,amixedmicellarmediumc...     

阻抑动力学光度法测定痕量邻二硝基苯

研究发现 ,在盐酸介质中 ,痕量邻二硝基苯能灵敏地阻抑高碘酸钾氧化中性红褪色。中红性、盐酸、高碘酸钾的最佳用量分别为 0 5 5 ,0 6 0 ,0 6 0mL ,反应温度 80℃ ,反应时间 6min。研究了该阻抑褪色反应的最佳条件及动力学参数 ,建立了一种测定痕量邻二硝基苯的新方法。该法测定线性范围为0 0～ 4.0 μg/L ,检测限为 7.7× 10 -7g/L。用于环境水样中邻二硝基苯的测定 ,结果满意。     

Achieving room temperature phosphorescence from organic small molecules on amino acid skeleton

Room temperature phosphorescence (RTP) generated by small molecules has attracted great attention due to their unique potentials for biosensor, bioimaging and security protection. While, the design of RTP materials is extremely challenging for organic small molecules in non-crystalline solid state. Herein, we report a new strategy for achieving non-crystalline organic small molecules with RTP emission by modifying different phosphors onto diphenylalanine or phenylalanine derivatives. Benefiting from the skeletal structure of the amino acid derivatives, there are intermolecular hydrogen bond formation and rigidification effect, thereby minimizing the intermolecular motions and enhancing their RTP performance     

Dinuclear ReI complex based on 1,2,4,5-tetrakis(diphenylphosphino)- pyridine: synthesis and luminescence properties

The reaction of 1,2,4,5-tetrakis(diphenylphosphino)pyridine (L) with Re(CO)₅Br (in a molar ratio of 1:2) leads to the bis-chelated complex [Re₂(CO)₆(L)Br₂] in 95% yield. At ambient temperature, the solid complex exhibits green phosphorescence (λ_max = 535 nm) with a quantum yield of 12% and a lifetime of 90 μs.