大量锆存在下铪镧钼杂多酸—耐尔蓝体系测定给

本文研究了耐尔蓝（ＮＢ）－给镧钼杂多酸（ＨｆＬａＭｏ－聚乙烯醇（ＰＶＡ）体系测定铪的超高灵敏光度法。在ＰＶＡ存在下，铪，镧和钼酸铵形成杂多酸，继而与耐尔蓝形成离子缔合物。其适宜条件为〔ＨＣｌｏ４〕＝１．２ｍｏｌ／Ｌ，〔Ｌａ×３＋〕＝２．９×１０＾－７ｍｏｌ／Ｌ，〔ＭｏＯ４×２－〕＝１．１×１０＾－３ｍｏｌ／Ｌ，〔ＮＢ〕＝２．７×１０＾－６ｍｏｌ／Ｌ，ＰＶＡ０．０８％。离子缔合物的最大吸收波长在５９     

硫酸耐尔蓝共振光散射法测定羧甲基纤维素钠

硫酸耐尔蓝共振光散射法测定羧甲基纤维素钠;羧甲基纤维素钠;硫酸耐尔蓝;共振瑞利散射;共振非线性散射     

金－钼酸盐－耐尔蓝缔合显色反应的研究

在聚乙烯醇存在下，金与钼酸盐形成络阴离子，继而与耐尔蓝形成离子缔合物，其最大吸收位于５９５ｎｍ，表现摩尔吸光系数ε值为２．７１×１０￣５Ｌ．ｍｏｌ￣（－１）．ｃｍ￣（－１），线性范围０～１６μｇ／２５ｍＬＡｕ，大多数离子不干扰。用于岩矿和冶金产品中金的测定，结果满意。     

介体型乙醇生物传感器的研制及应用

本文报道了电流型乙醇生物传感器的研制与应用。该传感器以健合型耐尔蓝修饰浸蜡石墨电极为基体电极，将乙醇脱氢酶及ＮＡＤ＾＋固定在人造丝网上，成为一种无试剂的乙醇生物传感器。在ｐＨ８．８的Ｔｒｉｓ／ＨＣｌ介质中，该传感器的响应电流与乙醇浓度在０．１０－１．０ｍｍｏｌ／ｌ范围内有良好的线性关系。     

耐尔兰A修饰碳纤维微柱电极的电化学性质研究

用循环伏安法将碳纤维柱电极表面官能团化，利用正负离子间的静电作用将耐尔兰Ａ修饰在碳纤维微柱电极（ＣＦＭＣＥ）表面，对该修饰电极的电化学性质进行研究，讨论了它的稳定性，测定了不同ＰＨ值下固定化耐尔兰Ａ电极反应的表现电子转移速率常数ｋ、电荷转移系数α以及参加电极反应的Ｈ＾＋数，实验表明：电极对血戏蛋白在ＣＦＭＣＥ上的还原有电催化作用。     

酸度对AgCl溶胶表面吸附H2TPP化学反应的影响

讨论了ｍｅｓｏ四苯基卟啉（Ｈ２ＴＰＰ）吸附在ＡｇＣｌ溶胶表面的吸收光谱。实验表明,当ｐＨ＝２．０～６．０时,Ｈ２ＴＰＰ吸附于ＡｇＣｌ溶胶表面以卟啉二酸Ｈ４ＴＰＰ２＋存在;当ｐＨ＝６．７５～１１．０时,Ｈ２ＴＰＰ吸附于ＡｇＣｌ溶胶表面发生络合反应,生成二价银络合物Ａｇ（Ⅱ）ＴＰＰ,并且络合反应的速率随ｐＨ值的增大而加快。     

磷钼钒杂多酸耐尔蓝多元络合物的分光光度法及其用于硅酸盐单矿物中钒的测定

本文提出了磷钼钒杂多酸与耐尔蓝形成的离子缔合物并研究了它的性质及其应用,该络合物在水相中呈蓝色,它和试剂的最大吸收峰分别为570、630nm,表观摩尔吸光系数为1.3×10~5,在0-10μgV_2O_550ml中符合比尔定律。磷钼钒杂多酸与耐尔蓝的组成比为1:4。提高酸度可以降低过剩试剂吸光度,加入磷酸可消除钛的干扰,不经任何分离可以测定岩矿中微量钒。     

用金钨杂多酸和耐尔蓝光度法测定纳克量金

在阿拉伯胶存在下，金与钨酸钠和耐尔蓝（ＮＢ）形成离子缔合物，它的最大吸收位于５８０ｎｍ，表观摩尔吸光系数ε值为２．３８×１０＾７Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，体系至少稳定２４ｈ。金量在０￣４．４μｇ／Ｌ范围内服从比尔定律，检测限（３σ）为０．０６９μｇ／Ｌ（ｎ＝１２），对４．０μｇ／Ｌ Ａｕ（Ⅲ）测定的相对标准偏差为１．９％（ｎ＝１１），离子缔合物的摩尔比为Ａｕ（Ⅲ）：ＮＢ＝１：３。考察了４０多种     

表面吸附质对银亚胶体吸光特性的影响

纯银溶胶在390nm处有一吸收峰。当银溶胶吸附了1-苯基-5-巯基四氮唑(PMT)或2-巯基苯骈噻唑(MBT)时, 银溶胶由亮黄色转变为橙红色, 即在510～550nm处出现一个新的吸收峰。研究发现, 卤素离子在银溶胶颗粒上与PMT和MBT有竞争吸附作用。但是卤离子对银溶胶的光谱吸收的影响完全不同于PMT和MBT。在讨论这种差别时应首先考虑金属银溶胶颗粒表面性质因吸附不同物质所产生的变化。     

醌亚胺类碱性染料荧光猝灭法测定肝素钠

建立了醌亚胺类碱性染料(藏红O、中性红、耐尔蓝A)荧光猝灭法测定肝素钠的方法。方法的线性范围和检出限分别为0.008~0.8 mg/L,3μg/L(藏红O体系);0.06~2.0 mg/L,40μg/L(中性红体系);0.05~1.0 mg/L,20μg/L(耐尔蓝A体系),其中以藏红O体系最为灵敏。以藏红O体系为例研究了共存物质的影响,方法已用于肝素钠注射液效价的测定。     

A Spectroscopic Study of the Effects of Various Solvents and Sol-Gel Hosts on the Chemical and Photochemical Properties of Thionin and Nile Blue A

Tetraethyl orthosilicate (TEOS)-based gels were doped with two optically active organic indicators, thionin and nile blue A. Before trapping in a sol-gel host, thionin and nile blue A were both evaluated for solvent and protonation effects on their spectral properties. Only extreme pH values provided by HCl, NaOH, and NH₄OH produced new absorption and/or fluorescence bands. Introduction of nile blue A into alkaline environments (0.1N NaOH, NH₄OH) results in the appearance of a broad absorption band centered near 520 nm whereas highly acidic environments (1N HCl) show a reduction of the 635 nm absorption peak accompanied by an absorption band located near 460 nm. A marked decrease is observed in the optical density of thionin in 1N HCl solution which results in a reduction in the fluorescence intensity. The absorption and fluorescence spectra also reveal a decrease in a pH 11 solution of NH₄OH as compared to neutral conditions. Both dyes formed dimers when the sol-gel host, initially synthesized with TEOS, was organically modified with methyltrimethoxysilane (MTMS). However, thionin dimers were present in all silica-based sol-gel compositions, as evidenced by the absorption and fluorescence spectra. Substitution of MTMS for some of the TEOS in the gel matrix resulted in blue shifts in the absorption and fluorescence spectra of nile blue A. The absorption peak shifted 50 nm to 596 nm whereas the fluorescence shifted around 40 nm to 635 nm. These blue shifts resulted from the reduced polarity of the silica-based xerogel. Thionin also exhibited shifts in its absorption and fluorescence spectra with organic modification by MTMS. The absorption shifted approximately 3 nm to 595 nm while the fluorescence maximum decreased 7 nm to 630 nm. The blue shifts in the spectra of thionin with additions of MTMS were attributed to surface sites that altered the molecular structure of the adsorbed thionin molecules.     

Time-dependent SERS of pseudoisocyanine on silver particles generated in silver bromide sol by laser illumination

SERS spectra of pseudoisocyanine dye (PIC) in silver bromide sols show a strong time-dependence. The enhancement factor, in general, follows the formation (and destruction) of SERS-active colloidal silver in the silver halide sols by laser illumination during the Raman measurement. Changes in the relative intensities within a characteristic fine triplet of the SERS spectrum show that the surface potential which is “seen” by the dye molecules shifts to more positive values with longer times. In particular, the values of the potential hint at the existence of Ag₁ and Ag₄ … Ag₆ clusters as SERS-active adsorption sites of the dye molecules in AgBr sols.     

近场激光热透镜光谱法测定催化反应动力学参数的研究

激光热透镜光谱法(LTLS)是一种高灵敏光热光谱分析技术,可测定10－’~10－’吸光度[‘j．LTLS既可     

Molecular reorientation dynamics and microscopic friction in liquids

Molecular rotation reorientation times are investigated using time resolved fluorescence depolarization studies of three solutes of similar size and shape (nile red, neutral nile blue and cationic nile blue) dissolved in alcohol and alkane solvents as well as an extensive compilation of previous results for neautral and charged solutes dissolved in non-polar, polar and associated solvents. A universal correlation is foung between reorientation time, solvent viscosity, and solute volume for solutes dissolved in alkanes, while strongly interacting solutes experience relatively enhanced friction, and non-polar solutes dissolved in alcohols experience reduced friction. The results are compared and contrasted with slip and stick hydrodynamic predictions, and used to develop empirical correlations, which can be used to predict molecular reorientation times with an uncetainty on the order of a factor of two in virtually any solute-solvent system.     

Lengthening of fluorescence lifetimes in self-organized metal-organic assemblies

Resonance energy transfer from tris(2,2'-bipyridyl)ruthenium (II) ([Ru(bpy)3](2+)) to nile blue A is demonstrated in aqueous solution in the presence of sodium dodecyl sulfate (SDS). At SDS concentrations below the critical micelle concentration, aggregates that permit energy transfer between these dyes at optically dilute (10 microM) concentrations with nearly 100% efficiency are formed. The disparity between the lifetimes of the donor and acceptor results in the lengthening of the photoluminescence lifetime of the sensitized emission observed from nile blue A. Time-resolved luminescence measurements confirm that the long-lived components of the emission originate from sensitized acceptor emission.     

Ultrasensitive Spectrophotometric Method for the Determination of Trace Bismuth with Tungstate and Rhodamine 6G

Bismuth can be determined with various chromogenic agents, such as xylenol orange and Bromopyrogallol red-Ethyl violet. In most of the methods, the sensitivity is very poor. The spectrophotometric determination of tellurium(IV) as ion-association complex of the tellurium with tungstate and nile blue in aqueous solution in the presence of polyvinyl alcohol(PVA) has been reported.     

N,N'-二乙基喹啉菁染料分子吸附在溴化银溶胶上的表面增强喇曼散射

N,N'-二乙基喹啉菁染料分子吸附在硫敏化过的溴化银溶胶上产生强的表面增强喇曼散射,这种散射实际上是在直晒银上产生的。N,N'-二乙基喹啉菁染料分子吸附在硫敏化过的溴化银溶胶和银溶胶上的喇曼谱基本相似。而未经硫敏化的溴化银溶胶和经硫敏化后再被高硫酸钠氧化的溴化银溶胶中测不到N,N'-二乙基喹啉菁染料的表面增强喇曼信号。本实验进一步表明,表面增强喇曼散射方法可以用于感光机理的研究。     

Effect of ionizing radiaton on the stability of colloidal silver and other metals in aqueous solutions

The effect of ionizing radiation (accelerated electrons and γ-rays of⁶⁰Co) on the stability of aqueous solutions of colloidal silver was studied. The threshold of absorbed dose, at which the stability dramatically decreases and coagulation of the metal occurs, was found. This critical dose corresponds to the reduction of silver ions that determine the electrical potential of the sols. “Radiation” neutralization was also found for cadmium sols and was not observed in the case of thallium, copper, or platinum. A mechanism of the effect of radiation, taking into account the electrostatic factor in the stability of metal sols, was considered. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 259–264, February, 1997.     

Adsorption of cations onto the surfaces of silver nanoparticles

The effects of cations on the absorption spectra of silver sols have been investigated by the UV-vis spectrometry and TEM. Experiments showed that injection of certain amounts of transition metal cations into silver sols resulted not only in the aggregation of silver nanoparticles but also in the appearance of a new band centered near 510 nm in the absorption spectra of silver sols. However, the new band was not observed in the presence of alkaline earth metal cations or the Mv2+ cations. The peak position of the new band depends on the nature as well as the concentration of metal cations used. Comparing the peak positions of the new bands, it was found that the new band induced by the injection of Cr3+ was red-shifted with respect to those induced by Cu2+, Zn2+, or the Cd2+ cations. It is reasonable that this band near 510 nm should be attributed to the coeffects of the adsorption of metal cations onto the surfaces of silver nanoparticles and the aggregation of silver nanoparticles.     

Highly Sensitive Fluorometric Assay Method for Acetylcholinesterase Inhibitor Based on Nile Red‐Adsorbed Gold Nanoparticles

A new sensitive fluorometric assay method for acetylcholinesterase (AChE) and its inhibitor was developed using a fluorescent dye, nile red (NR). Due to the fluorescence resonance energy transfer between the NR and the gold nanoparticle (AuNPs), the fluorescence was quenched. AChE can break down acetylthiocholine to produce a thiol‐bearing compound, thiocholine. In the presence of thiocholine, the nile red is replaced from the AuNPs surfaces and simultaneously transformed to a derivative of nile red. The fluorescence intensity of the derivative is much stronger than that of the native nile red with the same concentration and its maximum emission wavelength has a blue shift so that the sensor achieves a good signal‐to‐background ratio. In addition, when organophosphate pesticide (OPs) exists, the activity of AChE can be inhibited, the generation of thiocholine will be prevented and no fluorescence enhancement occurs. The results show that the method is sensitive to AChE and paraoxon with the detection limits of 0.2 mU/mL and 0.05 ng/mL, respectively.