5，10，15，20-四 [4-(4''-乙基哌嗪基)苯基]卟啉的合成及其与DNA的相互作用

基于卟啉对癌细胞的特殊亲和作用和哌嗪化合物的抗肿瘤、抗病毒作用，设计并合成了具有哌嗪结构的新型卟啉化合物5，10，15，20-四[4-(4'-乙基哌嗪基)苯基]卟啉（TEPPPH₂），其结构经UV-Vis, 元素分析，¹H NMR等手段证明。采用UV-Vis光谱和荧光光谱研究了TEPPPH₂和小牛胸腺DNA 的相互作用模式和结合机理。实验发现，TEPPPH₂能嵌入到DNA的碱基对中，1个小牛胸腺DNA分子对TEPPPH₂分子的最大结合数n约为88，结合常数为8.4×10⁶mol•L^-1 。TEPPPH₂与DNA的结合数和结合常数大于已知的四（4-N-甲基吡啶基）卟啉和Ca/sal-his、Ni/sal–aln型席夫碱抗癌药物。     

[Cr(III)(SSA)(en)2]•2H2O配合物的合成、表征及性质研究

有机铬(III)配合物具有较高的生物利用率. 本文合成了一种新型磺基水杨酸铬(III)混配配合物[Cr(SSA)(en)₂]•2H₂O (SSA＝5-磺基水杨酸, en＝乙二胺), 通过红外、紫外、荧光光谱以及元素分析、电导率测定和X晶体衍射等方法对其结构进行了表征. 在pH 7.4, 0.05 mol•L^－1 Tris-HCl缓冲液中, 利用荧光光谱研究了配合物与人血清白蛋白的结合. 结果表明配合物可与人血清白蛋白以较强的分子间作用力结合, 条件结合常数为(2.7±0.1)×10⁴ mol•L^－1, 结合位点数为3.87. 在pH 7.4, 0.05 mol•L^－1 Tris-HCl缓冲液中, 观察了不同温度下EDTA和脱铁伴清蛋白为竞争剂的配体取代反应动力学行为, 其中37 ℃时反应速率常数分别为0.0142和0.0225 h^－1.     

钯(Ⅱ)三元配合物稳定性及其与DNA作用研究

合成了[Pd(bipy)(DL-gly)]Cl•2H₂₂O(2)两个钯三元配合物. 配合物１和２的稳定常数对数值lgβ分别为13.81和13.71, 表征常数ΔlgK、lgX高于统计值, 表明在配合物分子内存在d-p π电子协同效应. 紫外光谱、荧光光谱结果表明, 配合物１和２与鱼精DNA主要以插入方式键合, 键合常数分别为2.37×10⁶(1)和4.57×10⁶(2). CD光谱图也显示, 配合物与DNA分子之间发生了作用. 质粒pBR322 DNA的凝胶电泳图表明, 配合物浓度在3.0０×10^-3～7.5０×10^-4 mol •L^-1范围内对DNA分子有切割作用, 配合物浓度低于3.75×10^-4 mol •L^-1时则主要以插入方式与DNA键合.     

Determination of Nickel in Fuel Ethanol Using a Carbon Paste Modified Electrode Containing Dimethylglyoxime

A mercury-free electrode chemically modified with carbon paste containing dimethylglyoxime was used for determination of nickel in fuel ethanol. The instrumental parameters and composition of the modified paste were optimized. The analytical curve for nickel determination from 5.0 × 10⁻⁹ to 5.0 × 10⁻⁷ mol L⁻¹ was obtained using 25 min of accumulation time. The detection limit and amperometric sensitivity obtained for this method were 2.7 × 10⁻⁹ mol L⁻¹ and 5.2 × 10⁸ μA mol⁻¹ L, respectively. The values for nickel concentration in four commercial samples of fuel ethanol were obtained in the range of 1.1 × 10⁻⁸ to 6.9 × 10⁻⁸ mol L⁻¹. A comparison to graphite furnace atomic absorption spectrometry (GFAAS) was performed for nickel determination in commercial samples of ethanol.     

一种基于壳聚糖固定葡萄糖氧化酶的葡萄糖生物传感器的研究

本文选用生物相容性好的壳聚糖作为基体材料，使其与戊二醛交联成网状结构包埋葡萄糖氧化酶制成电化学传感器。这种壳聚糖膜不仅可以减小葡萄糖氧化酶的流失，而且能为酶提供了适宜的微环境。用红外光谱、紫外光谱及透射电镜对膜的形态和性质进行了表征。实验结果表明该传感器具有很快的响应速度，很好的稳定性和重现性，能选择性地催化葡萄糖并测定其浓度。该传感器的制备方法简单，成本低，于冰箱中放置两周信号保持在90％以上，对葡萄糖测量的线性范围为1×10^-5 - 3.4×10^-3mol•L^-1，当信噪比为3:1时检测限为5×10^-6mol•L^-1。     

H2O2-鲁米诺-荧光素钠-K2CO3高灵敏化学发光法测定二氧化碳

在碱性介质中, CO₃^2－对H₂O₂氧化鲁米诺化学发光反应具有重要作用, 荧光素钠对该反应具有很强的增敏作用. 据此, 建立了化学发光法测定二氧化碳的新方法. 方法的线性范围为1.0×10^－10～5.0×10^－6 mol•L^－1 CO₃^2－, 检出限为 1.2×10^－11 mol•L^－1 CO₃^2－ (相当于5.3×10^－10 g•L^－1 CO₂). 该方法用于室内外空气中二氧化碳含量的测定, 相对标准偏差1.8%～2.1% (n＝11), 加标实验回收率97.6%～101.4%. 论文还探讨了反应的发光机理, 发光反应很可能是由溶液中的CO₃^2－与H₂O₂作用而产生的活性自由基引发, 荧光素钠对发光的增敏作用为化学能量转移过程.     

R6G@γ-CD-MOFs复合物的制备及其在Fe3+离子传感中的应用

利用γ-环糊精（γ-CD）、氢氧化钾、甲醇和水,制备了γ-CD-MOFs,并使用X射线粉末衍射、热重分析和扫描电镜对其结构、稳定性和形貌进行表征。由于γ-CD-MOFs的结构中含有一维孔道,在其孔道中引入黄光发射的罗丹明6G （R6G）染料,获得了荧光复合材料R6G@γ-CD-MOFs,并探索了其对不同金属离子的荧光响应情况。实验结果表明,R6G@γ-CD-MOFs能够从12种金属离子中选择性传感Fe³⁺离子,在2×10^-4~2.0×10^-2 mol·L^-1范围内其荧光猝灭常数（K^sv）为1.03×10⁴ L·mol^-1。     

荧光法研究3-氨基苯硼酸与牛血清白蛋白间的相互作用

为了了解分子印迹反应的机理和最适宜的反应条件, 应用荧光猝灭法研究了3-氨基苯硼酸(APBA)与牛血清白蛋白(BSA)的相互作用, 二者的反应受到体系pH值、离子强度等关键因素的影响. 实验结果表明: 适宜的离子强度和pH值为6.25时, APBA与BSA的色氨酸残基的荧光猝灭反应的物质的量比为2∶1, 表观结合常数K_A＝1.0×10¹¹ L²• mol^－2, 说明二者间形成了较强的化学键. 通过上述研究, 明晰了3-氨基苯硼酸与牛血清白蛋白之间的作用机理, 有助于分离或富集蛋白质中BSA组分, 从而能够改进印迹和洗脱的效率.     

Electrochemical determination of malachite green using a multi-wall carbon nanotube modified glassy carbon electrode

A multi-wall carbon nanotube (MWNT) film-modified electrode is described for the determination of malachite green (MG). The electrochemical profile of MG was examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), suggesting that the MWNT film facilitates the electron transfer of MG in terms of a potential shift and then significantly enhances the oxidation peak current of MG. The experimental parameters, such as supporting electrolyte, thickness of MWNT film, scan rate and accumulation time, were optimized. Consequently, a sensitive and convenient electrochemical method is proposed for the determination of MG. The oxidation peak current is proportional to the concentration of MG over the range from 5.0 × 10⁻⁸ to 8.0 × 10⁻⁶ mol L⁻¹ obeying the following equation: i_p = 0.09 + 1.19 × 10⁷ C (r = 0.995, i_p in μA, C in mol L⁻¹). The detection limit is 6.0 × 10⁻⁹ mol L⁻¹ (signal to noise = 3) after 5 min of accumulation. Moreover, this method possesses good reproducibility (RSD is 5.6%, n = 8) as well as long-term stability. Finally, the new method was employed to determine MG in fish samples. Correspondence: W. Huang, Department of Chemistry, Hubei Institute for Nationalities, Enshi 445000, P.R. China     

罗布麻活性成分与人血清白蛋白结合的光谱学研究

应用荧光和紫外光谱研究了人血清白蛋白与罗布麻活性成分槲皮素(QUE)、芸香苷(RUT)和儿茶素(CAT)的结合机理. 在QUE与蛋白质浓度比小于3.5时, 其荧光猝灭机理主要是静态猝灭, 在药物浓度较高时动态猝灭所占的比例增加; RUT在整个实验浓度范围内对蛋白质的荧光猝灭机理为静态猝灭; CAT与蛋白质之间不能形成复合物, 其荧光猝灭主要由动态猝灭产生. QUE和RUT分别与蛋白质形成1∶1的复合物, 结合常数分别为(1.51±0.13)×10⁵和(0.81±0.08)×10⁵ L•mol^－1. 由于激发态质子转移, 与蛋白质的相互作用引起QUE和RUT内源荧光发射峰强度的明显增加, 进一步证实了它们与蛋白质的结合. 与蛋白质的结合也引起了QUE紫外吸收带的明显红移, 说明药物分子中的酚羟基发生了解离, 以离子形式与蛋白质发生作用. RUT的紫外吸收谱带没有明显移动, 说明它主要以中性状态与蛋白质结合. 应用与蛋白质作用后药物分子紫外吸收光谱的二阶导数谱, 对药物与蛋白质的结合模式进行了深入探讨.     

Functionalized manganese-doped zinc sulfide core/shell quantum dots as selective fluorescent chemodosimeters for silver ion

Zinc sulfide quantum dots doped with Mn(II) ions and coated with a shell of zinc sulfide were prepared, and their surface was modified with iminodiacetic acid to form a QDs-conjugate (QDs-IDA). Such modification effectively improves the water-solubility and luminescence quantum yield of the quantum dots. The optical properties and structural features were characterized by photometry, ¹H NMR and fluorescence spectroscopy. The results displayed that QDs-IDA selectively respond to Ag (I) ion in phosphate buffer solution (pH 7.3) in quenching the fluorescence of QDs-IDA. A good linear relationship exists in the concentration range from 5.0?×?10^?7 mol·L^?1 to 4.5?×?10^?6 mol·L^?1 and the detection limit is 2.6?×?10^?7 mol·L^?1. The sensing mechanism was assumed to result from complex formation between the iminodiacetic acid of QDs-IDA and silver (I) ion which promoted photo-induced electron transfer.     

Effect of silver nanoparticles concentration on the metal enhancement and quenching of ciprofloxacin fluorescence intensity

Concentration effect of silver nanoparticles (AgNPs) on the photophysical properties of ciprofloxacin (Cip) have been investigated using optical absorption and fluorescence techniques. When performed AgNPs solution was added to the Cip solution, metal-enhanced fluorescence intensity and a blue-shift of 20 nm in the maximum emission spectra of Cip has been observed. The enhanced intensity of this system is strongly dependent on the AgNPs concentration and largest at the 6.0 × 10^?6 mol L^?1. With increase of AgNPs concentration, quenching of fluorescence is observed. Stern–Volmer quenching constants have been calculated at four temperatures. The results show the quenching constants are directly correlated with temperature. It indicates the quenching mechanism is the dynamic quenching in nature rather than static quenching. From which we determined the activation energy for the quenching of Cip-AgNPs to be about 31.1 kJ mol^?1. In addition, in the presence of optimum AgNPs concentration, a sensitive fluorimetric method for the determination of ciprofloxacin at the range 5.0 × 10^?7–3.0 × 10^?5 mol L^?1 and the detection limit of 2 × 10^?8 mol L^?1 in solution is proposed.     

Simultaneous Detection of Dopamine and Uric Acid under Coexistence of Ascorbic Acid with DNA/Pt Nanocluster Modified Electrode

A novel biosensor by electrochemically codeposited Pt nanoclusters and DNA film was constructed and applied to detection of dopamine (DA) and uric acid (UA) in the presence of high concentration ascorbic acid (AA). Scanning electron microscopy and X‐ray photoelectron spectroscopy were used for characterization. This electrode was successfully used to resolve the overlapping voltammetric response of DA, UA and AA into three well‐defined peaks with a large anodic peak difference (ΔE_pa) of about 184 mV for DA and 324 mV for UA. The catalytic peak current obtained from differential pulse voltammetry was linearly dependent on the DA concentration from 1.1× 10^?7 to 3.8×10^?5 mol·L^?1 with a detection limit of 3.6×10^?8 mol·L^?1 (S/N=3) and on the UA concentration from 3.0×10^?7 to 5.7×10^?5 mol·L^?1 with a detection limit of 1.0×10^?7 mol·L^?1 with coexistence of 1.0×10^?3 mol·L^?1 AA. The modified electrode shows good sensitivity and selectivity.     

Determination of Sodium Hexametaphosphate in Beverages Based on the Fluorescence Quenching of Acridine Orange

Sodium hexametaphosphate was shown to form a complex with acridine orange by electrostatic interactions that induce fluorescence quenching. Analysis of fluorescence intensity showed that the process was dominated by static quenching, which was confirmed by absorption spectra and lifetime of the excited state. The decreased fluorescence intensity was directly proportional to the concentration of sodium hexametaphosphate between 8.0 × 10^?7 and 1.1 × 10^?5 mol L^?1 with a limit of detection of 5.3 × 10^?7 mol L^?1. Beverages were analyzed for sodium hexametaphosphate with recoveries between 91.7% and 108.3%.     

Study on the co-luminescence system Sm-Gd-BPMPHD-CTMAB and its analytical application

It has been found that the Sm-BPMPHD-CTMAB ion association system shows a strong fluorescence intensity. In this system some rare earth ions, such as Lu³⁺, Y³⁺, Gd³⁺ and Tb³⁺, exert an evident fluorescence enhancement effect. The formation conditions of the system and the factors affecting the columinescence effect were studied in detail in order to determine trace amounts of Sm³⁺. Under optimum conditions a linear relationship was obtained between the fluorescence intensity and the Sm³⁺ concentration in the range of 5.0×10^?8–8.0×10^?6 mol·L^?1. The detection limit of Sm³⁺ was 2.0×10^?8 mol·L^?1. The determination gave satisfactory results.     

Electrocatalysis Oxidation of GMP Based on Layered Double Hydroxide Functionalized with Anionic Surfactant and Room Temperature Ionic Liquid Modified Glassy Carbon Electrode

The electrocatalysis oxidation of guanosine‐5′‐monophosphate (GMP) was investigated on Mg‐Al layered double hydroxide (LDH) functionalized with sodium dodecyl sulfate (SDS) and room temperature ionic liquid (RTIL) modified glass carbon electrode (GCE). The cyclic voltammogram of GMP on the modified electrode (RTIL/ LDH‐SDS/GCE) exhibited a well defined anodic peak at 1.091 V in 0.2 mol·L^?1 pH 4.4 acetate buffer solution. The GMP oxidation was enhanced in the presence of anionic surfactant in the ?lms. The results suggest that the surfactant molecules intercalate the LDH layers to preconcentrate GMP molecules and the RTIL showed good ionic conductivity. The experimental parameters were optimized, the kinetic parameters were investigated and the probable oxidation mechanism was proposed. Under the optimized conditions, the oxidation peak current was proportional to GMP concentration in the range from 5.0×10^?7 to 1.0×10^?4 mol·L^?1 with the correlation coefficient of 0.9987 and the detection limit was 1.0×10^?7 mol·L^?1. The RTIL/LDH‐SDS/GCE showed a good electrochemical response to the oxidation of GMP and would be developed into a new biosensor.     

A lipase-based electrochemical biosensor for target DNA

A lipase-based electrochemical biosensor has been fabricated for the quantitative determination of target DNA. It is based on a stem-loop nucleic acid probe labeled with ferrocene containing a butanoate ester that is hydrolyzed by lipase. The other end of the probe DNA is linked, via carboxy groups, to magnetic nanoparticles. The binding of target DNA transforms the hairpin structure of the probe DNA and causes the exposure of ester bonds. This results in the release of electro-active ferrocene after hydrolysis of the ester bonds, and in an observable electrochemical response. The quantity of target DNA in the concentration range between 1?×?10^?12 mol·L^?1 and 1?×?10^?8 mol·L^?1 can be determined by measuring the electrochemical current. The method can detect target DNA with rapid response (30 min) and low interference.

Micellar‐Enhanced Spectrofluorimetric Determination of Trazodone Hydrochloride in Human Urine and Serum

Abstract

A novel developed spectrofluorimetric method for the determination of trazodone hydrochloride in the presence of sodium dodecyl sulfate (SDS) surfactant micelles was described. Under optimal conditions, there was a good linear relationship between fluorescence intensity and trazodone hydrochloride concentration in the range of 4.0×10^?9 to 8.0×10^?6 mol · l^?1with the detection limit of 1.3×10^?9 mol · l^?1 (S/N=3). This method has been used to determine trazodone hydrochloride in biological fluids.     

Determination of Melatonin in Rat Pineal Gland and Drug with Flow-Injection Chemiluminescence

A flow-injection chemiluminescence （CL） method for the determination of melatonin based on the CL reaction of melatonin with hydrogen peroxide and sodium hypochlorite （NaOCl） in a basic alkaline solution was developed. The possible CL mechanism has been discussed, and a proposal for the reaction pathway was given that singlet oxygen was clarified to be produced in this reaction system and was responsible for the CL emission. Under the optimized conditions, the linear concentration range of application was 1.0×10^-7-2.5 × 10^-4 moloL-I with a de- tection limit of 5.0 ×10^-8 moloL-1 （S/N= 3）. The relative standard deviation for eight repeated measurements of 1.0×10^-6 mol·L^-1 melatonin was 2.8%. The interferences of several important biological substances, some indole compound, cations and anions were studied. No interference was found for the anions, glucose, starch, most of cations and low concentration （less than 3.0 × 10^-6 mol·L^-1） of some biological substances and indole compound. The method was applied to the determination of melatonin in rat pineal gland and drug with satisfactory results. The sample throughput was 90 injections per hour.     

Chitosan‐Based Glucose Oxidase Electrodes Enhanced by Silver Nanoparticles

Silver nanoparticles enhanced glucose oxidase electrodes were prepared on the basis of chitosan matrix. The enzyme electrodes exhibited high sensitivity and excellent response performance to glucose with a linear range from 1×10^?6 to 8×10^?3 mol · L^?1. And the time reaching the steady‐state amperometric response was less than 5 seconds. The inhibition percentage of this enzyme electrode against copper ions concentration was linear ranging from 1.2×10^?6 to 5×10^?5 mol · L^?1. These properties of enzyme electrodes are probably due to the excellent electron transfer of silver nanoparticles and the orientation of glucose oxidase molecule.