现代细胞分析中的仪器分析方法

本文介绍了显微吸收（荧光）光度术、流式细胞术、图象分析技术和激光扫描共焦显微术等仪器分析方法的原理,并对其在细胞分析中的应用进行了评述。     

导数—同步荧光法同时测定尿液肾上腺素和去甲肾上腺素

１引言尿液肾上腺素（Ｅ）、去甲肾上腺素（ＮＥ）含量测定通常采用高效液相色谱、荧光分光光度法，前者虽然准确，但需要价格昂贵的仪器；后者由于Ｅ、ＮＥ氧化后产生的荧光光谱严重重叠，因而影响测定结果的准确性。本文将同步荧光扫描和导数光谱两种技术结合起来用于Ｅ、ＮＥ同时检测，获得了成功，建立一种简单、可靠、成本低廉、适合于常规开展的尿液Ｅ、ＮＥ测定方法。２实验部分２．１仪器与试剂ＨｉｔａｃｈｉＦ－４０１０型荧光分光光度讣（日本日立）；石英亚沸蒸馏器。２ｍｏｌ／ＬｐＨ８．６Ｔｒｉｓ－ＨＣＩ缓冲液（含０．１３…     

紫外可见分光光度技术的应用进展

介绍了近几年来紫外可见分光光度技术在仪器部件、多组分体系的测定,新技术应用进展以及与其他技术联用等方面的情况(引用文献33篇)。     

溶胶-凝胶分子印迹CsPbBr3量子点的构建及其在胆固醇荧光检测中的应用

该文研究了CsPbBr3量子点（QDs）作为一种新型荧光（FL）探针对胆固醇（CHO）的检测。以3-氨丙基三乙氧基硅烷（APTES）为功能单体,CHO为模板分子,采用溶胶－凝胶技术,将CHO引入到SiO2网络中,制备了CHO分子印迹膜保护的CsPbBr3@SiO2 QDs。该分子印迹膜既可降低空气、湿度等与CsPbBr3 QDs的接触,提高CsPbBr3 QDs的稳定性,又赋予CsPbBr3 QDs对CHO的选择性。检测过程中,CHO被捕获到CsPbBr3@SiO2QDs的印迹位点上,形成空间位阻,导致CsPbBr3 QDs荧光强度下降。在最优条件下,CsPbBr3 QDs的荧光猝灭效率和CHO浓度对数在1.00 × 10－11 ~ 5.00 × 10-8 mol·L－1范围内呈现良好的线性关系,检出限为2.48 × 10－12 mol·L－1。结果表明,该方法灵敏度高、选择性好。该工作为CHO检测提供了一种新的策略,拓宽了CsPbBr3 QDs的应用范围。     

荧光量子点及其在生物检测中的应用

量子点(QDs)是一种零维的半导体纳米晶体,与传统的有机染料相比,具有独特的光学特征。由于它们具有激发光谱宽、发射光谱窄、发射波长精确可调、量子产率高和荧光稳定性好等特点,作为新一代的生物荧光探针,已被广泛应用于生物检测。本文介绍了QDs的基本概念和性质,探讨了QDs的制备方法及表面修饰,对其毒性也作了简要分析,提供了QDs在荧光免疫分析、生物芯片、生物传感器及体内成像等方面的应用实例。随着技术发展的不断进展,QDs在生物分析领域有着更为广泛的潜在的应用前景。     

荧光量子点免疫标记法检测炭疽芽孢杆菌

建立了荧光量子点标记-免疫分析技术联用检测炭疽芽孢杆菌的方法.通过抗原抗体反应,结合生物素与亲和素间的特异性相互作用,将QDs特异性标记在炭疽芽孢杆菌上,并利用荧光显微镜和荧光分光光度计进行了验证.采用实验室自制的便携式荧光检测系统对标记QDs的炭疽芽孢杆菌样品进行定量检测.结果表明,在炭疽芽孢杆菌浓度在100～1×1...     

碲化镉量子点作为探针研究核黄素与鲑鱼精DNA的相互作用

在水相中合成了巯基丙酸包覆的CdTe量子点（CdTe QDs）,以CdTe QDs作为探针,在pH 7.25 Britton-Robinson（B-R）缓冲溶液中,应用荧光光谱法、紫外吸收光谱法,对核黄素（RF）与鲑鱼精DNA作用方式进行了研究.RF与DNA作用时,使荧光强度降低,紫外吸收明显减色,通过盐效应实验和DN...     

人发的光谱分析进展

评述了用分光光度、荧光（原子荧光）、原子吸收、原子发射光谱方法进行人发中我种元素测定的分析（包括发样采集、洗涤、消化），引用文献９６篇。     

紫外-可见吸收、荧光光谱研究CdTe/CdS量子点与盐酸药根碱的相互作用及其应用

合成了巯基乙酸（TGA）修饰的壳核型CdTe/CdS量子点（TGA-CdTe/CdS QDs）。 利用紫外-可见光谱吸收、荧光光谱研究TGA-CdTe/CdS QDs与盐酸药根碱（JH）的相互作用机理。 在pH值为7.4的tris-HCl缓冲溶液介质中,QDs与JH相互作用后使QDs的荧光呈线性猝灭,并有良好的线性关系（r=0.999 1）,线性范围0.011~10 mg/L,检出限（3σ）为3.3×10-3 mg/L,因此可以作为一种快速、简便、定量测定盐酸药根碱的新方法。     

量子点CdSe-ZnS与乳酸共聚物复合薄膜QDs/PLGA的谱学性能及聚合物薄膜体外降解行为研究

采用简单的溶液浇铸法制备了不同硒化镉-硫化锌核壳结构量子点(CdSe-ZnSQDs)含量的QDs/乳酸-乙醇酸共聚物(PLGA)纳米复合材料薄膜,对薄膜的微观结构、谱学性能等进行了系统的研究后,重点研究了PLGA、QDs/PLGA复合材料的体外降解行为.荧光光谱、紫外-可见光谱分析结果显示QDs与PLGA复合后仍具有稳定优异的发光性能和吸光度,且发光和吸光强度随QDs含量增加而增大.在体外降解的研究中,凝胶渗透色谱结果和磷酸盐缓冲液的pH值变化显示量子点的加入加快了PLGA的降解;而复合材料的荧光效应随着降解的进行而逐渐减弱.以上结果证明CdSe-ZnSQDs/PLGA纳米复合材料可采用简单的溶液浇铸法成功制备,且可通过检测荧光效应变化来监测QDs/PLGA复合材料的降解进程.     

表面修饰CdTe量子点的合成及其光学特性

在水相中合成高发光性能的CdTe量子点,研究以巯基乙酸(TGA)为稳定剂对CdTe表面进行修饰,制备在水中分散性良好的纳米晶,通过对CdTe量子点合成反应条件的摸索,掌握了其合成的反应规律.同时用紫外分光光度计、荧光分光光度计和透射电子显微镜对其进行了表征.结果表明,回流时间、n(Cd²⁺):n(HTe^-)、反应物浓度、TGA用量、反应体系pH值,对纳米晶的光学性质具有显著影响.回流2 h制得的CdTe纳米粒子直径约为5 nm,其发射峰窄且对称,表现出良好稳定的光学性质.     

Synthesis of highly monodisperse quantum dot‐loaded polymer beads by impregnation and precipitation techniques

A novel approach to the synthesis of highly monodisperse quantum dot‐loaded polymer beads by combining impregnation and precipitation techniques was reported. The monodisperse poly(glycidyl methacrylate) (PGMA) beads were first synthesized by dispersion polymerization. Then, the PGMA beads were chemically modified to generate carboxyl groups, and impregnation of cadmium ions (Cd²⁺) inside the beads. Subsequently, the cadmium ions were reacted with thioacetamide to form cadmium sulfide (CdS) quantum dots within the polymer beads. The morphology, structure, and properties of CdS quantum dot‐loaded polymer beads were studied by field emission scanning electron microscope (SEM), transmission electron microscope, fluorescence spectrophotometer, fluorescence microscope, Fourier transform infrared spectroscopy, powder X‐ray diffraction, and thermogravimetric analysis. The results indicated that the CdS quantum dot‐loaded polymer beads had an average size of 1.4 μm, and were highly monodisperse. More interestingly, the CdS quantum dots distributed evenly within the polymer beads, which provide very strong fluorescence intensity. The existence of carboxyl groups on the quantum dot‐loaded polymer beads was measured quantitatively, and was found to be 0.2 mmol/g. These CdS quantum dot‐loaded polymer beads involving functional carboxyl groups would have potential applications in biological immunoassay and photoelectronic fields. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Hydrothermal synthesis of fluorescent nitrogen-doped carbon quantum dots from ascorbic acid and valine for selective determination of picric acid in water samples

Nitrogen doped carbon quantum dots (N-CQDs) were synthesised by a hydrothermal method using ascorbic acid and valine as precursors. The as-synthesised N-CQDs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV?vis absorption spectra, as well as fluorescence spectrophotometer. The results revealed that the as-prepared N-CQDs were spherical shaped with an average diameter of 4 nm and emitted bright blue photoluminescence with a quantum yield of approximately 4.8 %. Additionally, we found that the fluorescence of the N-CQDs was intensively quenched by the addition of picric acid (PA). The decrease of the fluorescence intensity made it possible to determine PA in the linear range of 0.06–7.81 µg ml^–1 based on the fluorescence resonance energy transfer between PA and N-CQDs. The detection limit was as low as 11.46 ng ml^–1. The proposed approach was further successfully applied for the determination of PA in water sample collected from Fenhe river for public safety and security, suggesting its great potential towards water routine analysis.     

Optical and electrical control of circularly polarised fluorescence in CdSe quantum dots dispersed polymer stabilised cholesteric liquid crystal shutter

In the present communication, we report on the synthesis and electro-optic investigation of photosensitive CdSe quantum dots (QDs) dispersed polymer stabilised liquid crystal (PSCLC) luminescent gel. The assembly of the fluorescence properties of CdSe QDs facilitate the anisotropy of PSCLC gel and hence manipulates the optical and electro-optic switching properties, which was further investigated using polarised fluorescence spectrophotometer. The circularly polarised fluorescence intensity was tuned electrically so as to affect the orientations of liquid crystal in the helix. It was found that the electro-optic switching behaviour of QDs-doped sample predicts the improvement in threshold voltage and hence makes them applicable for the switchable liquid crystal contrivances with low power consumption.     

荧光光谱的罗丹明B校正原理

一般荧光光谱仪推荐的校正方法是罗丹明B法,但仪器说明书对该方法的原理没有介绍。本文通过研究不同浓度罗丹明B溶液的激发光谱、发射光谱和吸收光谱再结合理论分析阐明了罗丹明B浓溶液可作为量子计数器的原因及其校正光谱的原理。     

Fabrication of CdSe composite by using the amphiphilic block copolymer as template

CdSe nanoparticles of improved stability against aggregation were synthesized by using amphiphilic block copolymer polyacrylonitrile-block-poly(ethylene glycol)-block-polyacrylonitrile (PAN-b-PEG-b-PAN, PEA). The products were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopic (HRTEM). The optical properties were characterized by UV-vis spectrophotometer and the room temperature photoluminescence (PL). The results revealed that the CdSe nanoparticles have been uniformly distributed throughout the copolymer with diameters of 6-7 nm and the produced novel hybrid nanocomposites displayed obviously quantum size effects and interesting fluorescence features. FTIR results provided the information on the interaction between the copolymer and the nanoparticles. The TGA revealed that the thermal property of the copolymer enhanced due to the interaction of the nanoparticles and the groups of the copolymer.     

EXCITATION-ENERGY TRANSFER BETWEEN TYROSINE AND TRYPTOPHAN IN PROTEINS EVALUATED BY THE SIMULTANEOUS MEASUREMENT OF FLUORESCENCE AND ABSORBANCE

Abstract— The efficiencies of the excitation–energy transfer from tyrosine to tryptophan residues in eight globular proteins in the native and denatured states are obtained by studying the wavelength dependence of the fluorescence quantum yield. The measurements are made over a wide wavelength range using a computer-controlled spectrophotometer which can measure the fluorescence and absorbance simultaneously in one sample solution (Wada et al. , 1980). The values of the energy transfer efficiencies ranged from 0.17 ± 0.12 to 0.69 ± 0.06 in the native state and from -0.04 ± 0.09 to 0.12 ± 0.06 in the denatured state. These values are considerably lower than the values reported by Kronman and Holmes (1971); in particular, an almost complete absence of energy transfer for the denatured state is shown.     

A SPECTROPHOTOFLUOROMETER FOR MEASURING VERY WEAK FLUORESCENCES FROM BIOLOGICAL MOLECULES

Abstract —A spectrophotometer using the photon-counting method is described. The sample cuvette is mounted on a table which can be displaced in the X and Y directions, permitting investigation of absorption and self-absorption processes within the cuvette. Fluorescence detection is performed at right angles to the direction of the exciting beam, the analysis grating being driven by a stepping motor. The apparent spectrum is fed into a multichannel analyser and printed. Corrections are made to the data provided by the printer. Signal-to-noise ratio, fluorescence spectra and fluorescence excitation spectra are discussed in more detail for the case of more concentrated solutions. This very high sensitivity device allows room-temperature investigation of the fluorescent emission from neutral aqueous solutions of nucleic acid bases, nucleosides, nucleotides, dinucleotides etc., quantum yields for these molecules being of the order of 10^-4. A table of minimum concentration values of some commonly used fluorescent probes is given.     

CdS Quantum Dots as Fluorescence Probes for the Detection of Selenite

Abstract

Water-soluble cadmium sulfide (CdS) quantum dots (QD) capped by mercaptoacetic acid were synthesized by aqueous-phase arrested precipitation and characterized by transmission electron microscopy, a spectrofluorometer, and an ultraviolet visible (UV-Vis) spectrophotometer. Based on the fluorescence quenching of CdS QD by selenite in the presence of glutathione (GSH), a simple, rapid, sensitive, and selective detection method for selenite was proposed. Under the optimum conditions, the calibration graph was linear in the range of 0.05 µmol L^?1 to 11.2 µmol L^?1. The limit of detection is 0.03 µmol L^?1. The usefulness of the proposed method was evaluated for the determination of selenite in sodium selenite tablet and sodium selenite and vitamin E injection, and the results agreed with the labeled values. In addition, the effect of foreign ions (common anions and biologically relevant cations) on the fluorescence of the CdS QD was examined to evaluate the selectivity. The quenching mechanism is also described.