硝基磺酚C光度法测定蛋白质的研究

蛋白质的定量分析是生化研究、临床化验和食品检验等领域经常涉及的内容.以有机小分子作光谱探针测定蛋白质,如甲基橙^[1,2]、考马斯亮蓝G-250^[3]、溴酚蓝^[4]、溴甲酚绿^[5]和偶氮胂Ⅲ^[6]等已得到研究.     

二苯并噻吩及其氧化物与离子液体相互作用的理论研究

采用密度泛函理论方法比较了DBT/DBTO₂和[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-的相互作用。对最稳定的[BMIM]⁺[PF₆]^-、[BMIM]⁺[PF₆]^--DBT、[BMIM]⁺[PF₆]^--DBTO₂、[BMIM]⁺[BF₄]^-、[BMIM]⁺[BF₄]^--DBT、[BMIM]⁺[BF₄]^--DBTO₂进行了NBO和AIM分析。结果表明,DBT和[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-中的咪唑环彼此相互平行,NBO和AIM分析表明它们之间发生了π-π相互作用。H1'和H9'形成的F…H氢键有利于π-π堆积作用的形成。DBTO₂倾向于趋近C2-H2和甲基基团形成O…H相互作用;DBTO₂优先吸附在[BMIM]⁺[PF₆]^-/[BMIM]⁺[BF₄]^-。在模拟油中,[BMIM]⁺[PF₆]^-和[BMIM]⁺[BF₄]^-离子液体对DBTO₂的萃取能力大于DBT,其原因是可能是DBTO₂具有较大的极性和O…H与F…H的氢键作用。     

静电纺丝法制备NiO纳米纤维及其表征

纳米级NiO因具有优良的催化和热敏等性能而被广泛用于催化剂^[1]、电池电极^[2,3]、光电转化材料^[4～6]、电化学电容器^[7～8]等诸多方面.迄今,已成功地制备出N iO的纳米颗粒^[9]、纳米线^[10]及纳米薄膜^[11],但是对于具有准一维结构的NiO纳米纤维的制备及性能研究尚未见报道.     

微波消解-微波等离子体炬原子发射光谱法测定无铅汽油中痕量铅的研究

四乙基铅作为一种良好的抗爆添加剂,曾广泛用于汽油生产中,但由于四乙基铅有很强的毒性,目前国际上已停止生产和使用车用含铅汽油,因此在生产车用无铅汽油时严格控制和准确测定铅的含量十分必要.迄今,测定汽油中铅含量的常用方法是铬酸盐容量法^[1]、一氯化碘法^[2]、X射线光谱法^[3]、分光光度法^[4,5]、原子吸收光谱法^[6]和等离子体光谱法^[7].这些方法或操作烦琐,测定时间较长^[4],或灵敏度低^[1～3],或测定误差较大,且在测试中需使用毒性较大的四乙基铅^[5],或所需的氯化甲基三辛基铵不易购买^[6],或处理过程繁琐,且仪器设备昂贵^[7].因此,建立一种简便、快速、灵敏、准确和无毒副作用的测定无铅汽油中痕量铅的方法已显得十分迫切.近年来发展的微波等离子体炬原子发射光谱法^[8]已有商品化仪器问世^[9].本文利用微波等离子体炬原子发射光谱仪研究了无铅汽油中痕量铅的测定方法,并提出用微波消解法预处理无铅汽油样品,将微波消解技术与微波等离子体炬原子发射光谱法相结合,建立了简便、快速、灵敏、准确和无污染的测定无铅汽油中痕量铅的新方法.     

CF-2沸石的表面酸性及催化性能

CF-2是一种新型的高硅沸石。1981年我们实验室首先在二乙醇胺-甘油-Na₂O-SiO₂-Al₂O₃-H₂O体系中制备成功^[1],以后才见到关于Theta-1^[2],ISI-1^[3],KZ-2^[4],NO-10^[5]和ZSM-22^[6]沸石的报道。     

四(4-重氮基苯基)卟啉的合成及其与聚苯乙烯磺酸钠自组装的研究

卟啉是一类重要的功能性小分子染料,近年来,在光化学治疗^[1,2]、光电转换^[3,4]、传感元件^[5]、烯烃环氧化催化剂^[6]和光敏化剂^[7]等方面的研究与应用引起了人们的广泛注意.通过两亲卟啉分子衍生物,或带有负电荷的卟啉衍生物,特别是带磺酸基的卟啉分子与正离子聚电解质自组装,制备带有卟啉结构单元的LB膜和自组装膜已有很多报道^[8～14].     

植物生物分子的电分析化学研究Ⅷ.秋水仙碱的微分脉冲极谱行为及分析应用

秋水仙碱是近年来新发现的有前途的抗癌植物有效成分。秋水仙碱的测定方法,如容量滴定法^[1]、电位滴定法^[2]、紫外分光光度法^[3]、荧光分析法^[4]和高效液相色谱法^[5]等,手续均不太简便。电化学分析研究秋水仙碱主要有阳极伏安法^[6]和交流极谱法^[7],前者因使用固态电极,重现性较差。后者用非水溶剂作介质,灵敏度不高。     

N,N,N＇,N＇-四苄基取代方块菁染料LB膜研究

方块菁染料在有机光导材料^[1,2]、有机太阳能存储^[2,3]、光记录^[4、有机光盘中红外吸收器^[4]以及光纤识别功能薄膜等领域中有着广泛应用前景.     

一系列Ru(II)配合物电致化学发光性质的比较研究

比较研究了以C₂O₄^2－为共反应物时5个结构相关的Ru(II)配合物[Ru(bpy)₂L¹]^2＋, [Ru(bpy)₂L²]^2＋, [Ru(bpy)₂L³]^2＋, [Ru(phen)₂L¹]^2＋和[Ru(phen)₂L²]^2＋(其中bpy＝2,2′-联吡啶, phen＝1,10-邻菲啰啉, L¹＝4-羧基苯基咪唑[4,5-f][1,10]邻菲啰啉, L²＝3-羧基-4-羟基苯基咪唑[4,5-f][1,10]邻菲啰啉, L³＝3,4-二羟基苯基咪唑[4,5-f][1,10]邻菲啰啉)的电致化学发光(ECL)性质. 结果表明, 酚羟基的存在能有效地淬灭Ru(II)配合物[Ru(bpy)₂L²]^2＋, [Ru(bpy)₂L³]^2＋和[Ru(phen)₂L²]^2＋的ECL, 其它Ru(II)配合物的ECL量子效率与[Ru(bpy)₃]^2＋相差不大.     

零电流示波电位滴定盐酸异丙嗪

盐酸异丙嗪是一种较重要的抗组胺药,现行的分析标准为非水滴定法^[1],此外尚有分光光度法^[2]、伏安法^[3]、电极法^[4]、液相色谱法^[5]和流动注射分析法^[6]等。本文将高鸿提出的零电流示波电位滴定法^[7]中的铂片电极修饰一层含四苯基硼酸-异丙嗪电活性物质的PVC膜,使电极对异丙嗪产生响应,可用于四苯基硼酸钠直接滴定异丙嗪的终点指示。     

Determination of dioxopromethazine hydrochloride by capillary electrophoresis with electrochemiluminescence detection

The paper presents a rapid method for the determination of dioxopromethazine hydrochloride (DPZ), an antihistamine drug, by the capillary electrophoresis with electrochemiluminescene detection (CE–ECL) using tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) reagent. This CE–ECL detection method has high sensitivity, good selectivity and reproducibility for DPZ analysis. Under the optimized conditions: separation capillary, 38 cm length (25 μm i.d.); sample injection, 10 s at 8 kV; separation voltage, 12.5 kV; running buffer, 20 mmol L⁻¹ sodium phosphate of pH 6.0; detection potential, 1.15 V; 50 mmol L⁻¹ of phosphate buffer (pH 7.14) containing 5 mmol L⁻¹ of Ru(bpy)₃²⁺ in ECL detection cell, the detection limit of DPZ was 0.05 μmol L⁻¹ (S/N = 3). The linear range extended from 5 to 100 μmol L⁻¹. The linear curve obtained was Y = 181.62 + 9.28X with a correlation coefficient of 0.9970. The relative standard deviations of the ECL intensity and the migration time for six continuous injections of 5 μmol L⁻¹ DPZ were 3.7% and 0.92%, respectively. The CE–ECL method was applied to analyze DPZ in real samples including tablets, rat serum and human urine, and satisfactory results were obtained without interference from samples matrix. The CE–ECL technique was proved to be a potential method for the detection of DPZ in clinic analysis.     

Rates of virtually self-exchange energy transfer processes of ruthenium(II) polypyridine complexes

The rate constants of electronic energy transfer from the lowest excited state of Ru(bpy)₂(L)²⁺ or Ru(bpy)(L)₂²⁺ 10 Ru(L)₃²⁺ (b     

Electrochemiluminescent behavior of melatonin and its important derivatives in the presence of Ru(bpy)(3)(2+)

Melatonin and some of its important derivatives were found to be able to enhance the ECL of Ru(bpy)₃²⁺ in an alkaline Britton–Robinson buffer solution. The optimum conditions for the enhanced ECL, such as the selection of applied potential mode, type of buffer solution, pH effect and effect of Ru(bpy)₃²⁺ concentration have been investigated in detail in this paper. Under the optimum conditions, the enhanced ECL is linear with the concentration of melatonin and its derivatives over the wide range, and the detection limit for these compounds was found to be in the range of 5.0 × 10⁻⁸ to 1.0 × 10⁻¹⁰ mol L⁻¹. The proposed procedure was applied for the determination of drug in tablets with recoveries of 85–93%. A possible mechanism for the enhanced ECL of Ru(bpy)₃²⁺ by melatonin and its derivatives was proposed, and the relationship between molecular structure of melatonin and its derivatives and the enhanced ECL behavior was also discussed.     

Capillary electrophoresis with electrochemiluminescence detection of procyclidine in human urine pretreated by ion-exchange cartridge

This paper describe a Ru(bpy)₃²⁺ based electrochemiluminescence (ECL) method to detect procyclidine in human urine following separation by capillary electrophoresis (CE). An ECL detection cell was designed for post-column addition of Ru(bpy)₃²⁺. Parameters affecting separation and detection were optimized, leading to a detection limit of 1×10⁻⁹ mol/l in an on-capillary stacking mode. For application in urine, a cartridge packed with slightly acidic cation-exchange resin was used to eliminate the matrix effects of urine and improve the detection sensitivity. Extraction recovery was nearly 90%.     

Hydrogen peroxide photoproduction by the semicarbazide—tris(2,2′-bipyridine)ruthenium(II)—oxygen system

A light-driven system consisting of tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)₃²⁺) as the photosensitizer, semicarbazide as the electron donor and molecular oxygen as the electron acceptor has been employed for hydrogen peroxide production. The efficiency of this photosystem markedly depends on pH: while the peroxide yield is almost negligible at acid, neutral or slightly alkaline pH, it reaches significant values at high hydroxide concentrations, the initial rate of H₂O₂ formation drastically increasing from pH 12 to pH 14. In 1 M NaOH solutions containing Ru(bpy)₃²⁺ and semicarbazide at optimum concentrations, the number of catalytic cycles (or turnover number) undergone by the ruthenium complex over the complete course of the photochemical reaction is as high as 1.1 × 10⁴.

Spectrofluorometric and laser flash photolysis techniques were used to study the primary photochemical reactions involving the excited state of the ruthenium complex as well as the photochemically generated species Ru(bpy)₃³⁺ and Ru(bpy)₃⁺. It is proposed that at pH 14 a sequence of reactions leading to O₂ photoreduction by electrons from semicarbazide takes place, with the concomitant formation of H₂O₂; the excited state of Ru(bpy)₃²⁺ appears to react via oxidative quenching by oxygen rather than via reductive quenching by semicarbazide. At neutral pH, in contrast, there is no H₂O₂ formation owing to the fact that semicarbazide is unable to reduce (Ru(bpy)₃³⁺ to Ru(bpy)₃²⁺, although the photoexcited ruthenium complex is quenched equally by oxygen.     

Characterization of the low-oxidation-potential electrogenerated chemiluminescence of tris(2,2′-bipyridine)ruthenium(II) with tri-n-propylamine as coreactant

The electrogenerated chemiluminescence (ECL) of the Ru(bpy)₃²⁺ (bpy, 2,2′-bipyridine)/tri-n-propylamine (TPrA) system can be produced at an oxidation-potential well before the oxidation of Ru(bpy)₃²⁺. Here, we describe the unique features of the low-oxidation-potential (LOP) ECL. The LOP ECL exhibited strong dependence on solution pH with the maximum emission at pH  7.7. Compared with the conventional ECL, the LOP ECL was much more significantly diminished at high pH (>10), probably due to the short lifetime of TPrA cation radical which is a crucial intermediate for the LOP emission. It was also found that the preceding deprotonation step played an important role in TPrA oxidation at neutral pH and would remarkably influence the emission intensity. As excess intermediate radicals were produced upon rapid TPrA oxidation, only 5 mM TPrA was needed to achieve the maximum LOP ECL intensity in detecting trace Ru(bpy)₃²⁺ (<1 μM) and the LOP ECL response to Ru(bpy)₃²⁺ concentration was linear. Compared with the conventional Ru(bpy)₃²⁺/TPrA ECL, the LOP ECL technique not only produces higher emission intensity at lower oxidation-potential, but also significantly reduces the amount of the coreactant.     

Direct tris(2,2'-bipyridyl)ruthenium (II) electrochemiluminescence detection of polyamines separated by capillary electrophoresis

Capillary electrophoresis (CE) with tris(2,2'-bipyridyl) ruthenium (II) (Ru(bpy)3(2+)) electrochemiluminescence (ECL) detection technique was developed for the analysis of four polyamines (putrescine (Put), cadaverine (Cad), spermidine (Spd), and spermine (Spm)) analysis. The four polyamines contain different amine groups, which have different ECL activity. There are several parameters which influence the resolution and ECL peak intensities, including the buffer pH and concentrations, separation voltage, sample injection, electrode materials, and Ru(bpy)3(2+) concentrations. Polyamines are separated by capillary zone electrophoresis in an uncoated fused-silica capillary (50 cmx25 micro m (ID) filled with acidic phosphate buffer (200 mmol/L phosphate, pH 2.0) - 1mol/L phosphoric acid (9:1 v/v) and a separation voltage of 5 kV (25 micro A), with end-column Ru(bpy)3(2+) ECL detection. A 5 mmol/L Ru(bpy)3(2+) solution plus 200 mmol/L phosphate buffer (pH 11.0) is added into the reagent reservoir. The calibration curve is linear over a concentration range of two or three orders of magnitude for the polyamines. The analysis time is less than 25 min. Detection limits for Put and Cad are 1.9x10(-7) mol/L and 7.6x10(-9) mol/L for Spd and Spm, respectively. Intraday and interday relative standard deviations of ECL peak intensities are less than 8%. The main advantages of this CE-ECL detection technique for polyamines analysis presented herein are the omission of chemical derivatization of the analytes and the high selectivity.     

Stabilization and electron spin resonance characterization of Ru(bpy)3 and Ru(bpy)3 by radiolysis of Ru(bpy)3 adsorbed on silica gel

Ru(bpy)₃³⁺, which is important in artificial photosynthetic systems due to its high reduction potential, is stabilized together with its counter anion, Ru(bpy)₃⁺, by radiolysis of Ru(bpy)₃²⁺ adsorbed on silica gel at 77 K. Both species are characterized by electron spin resonance.     

Electrochemiluminescent behavior of allopurinol in the presence of Ru(bpy)(3)(2+)

The electrochemiluminescent (ECL) response of allopurinol was studied in aqueous media over a wide pH range (pH 2–13) using flow injection (FI) analysis. It was revealed that allopurinol itself had no ECL activity, but could greatly enhance the ECL of Ru(bpy)₃²⁺ in alkaline media giving rise to a sensitive FI-ECL response. The effects of experimental conditions including the mode of applied voltage signal, the potential of working electrode, pH value, the flow rate of carrier solution, and the concentration of Ru(bpy)₃²⁺ and allopurinol on the ECL intensity were investigated in detail. The most sensitive FI-ECL response of allopurinol was found at pH 12.0, where the FIA-ECL intensity showed a linear relationship with concentration of allopurinol in the range 1 × 10⁻⁸ mol L⁻¹ to 5 × 10⁻⁷ mol L⁻¹, and the detection limit was 5 × 10⁻⁹ mol L⁻¹.     

ss-DNA在纳米金上固载和杂化的电化学传感研究

将2-氨乙基硫醇(AET)固载到玻碳电极(GCE)表面,进而化学吸附纳米金(NG),并在纳米金上固载ss-DNA得到ss-DNA/NG/AET/GCE,以Co(bpy)₃³⁺为电化学指示剂可以识别研究ss-DNA的杂化反应.结果表明,纳米金能使固载其上的ss-DNA发生部分变性而结合Co(bpy)₃³⁺,但用pH7.0的磷酸缓冲液浸泡可基本上避免这种变性,并明显提高杂化反应的识别能力.结合在ds-DNA/NG/AET/GCE上的Co(bpy)₃³⁺的峰电流与扫速的线性关系可保持到80mV/s.与电沉积法固载纳米金相比较,本电极更稳定和可靠.