A simple and compact fluorescence detection system for capillary electrophoresis and its application to food analysis

A novel fluorescence detection system for CE was described and evaluated. Two miniature laser pointers were used as the excitation source. A Y‐style optical fiber was used to transmit the excitation light and a four‐branch optical fiber was used to collect the fluorescence. The optical fiber and optical filter were imported into a photomultiplier tube without any extra fixing device. A simplified PDMS detection cell was designed with guide channels through which the optical fibers were easily aligned to the detection window of separation capillary. According to different requirements, laser pointers and different filters were selected by simple switching and replacement. The fluorescence from four different directions was collected at the same detecting point. Thus, the sensitivity was enhanced without peak broadening. The fluorescence detection system was simple, compact, low‐cost, and highly sensitive, with its functionality demonstrated by the separation and determination of red dyes and fluorescent whitening agents. The detection limit of rhodamine 6G was 7.7 nM (S/N = 3). The system was further applied to determine illegal food dyes. The CE system is potentially eligible for food safety analysis.     

Spectral correlative chromatography and its application to analysis of chromatographic fingerprints of herbal medicines

A signal-processing method known as spectral correlative chromatography (SCC) for two-dimensional data obtained from hyphenated chromatography is developed and applied to chemical chromatographic fingerprint data sets of herbal medicine under specific experimental conditions. The method can judge the presence or absence of a spectral correlative peak among the spectrochromatograms. A local least squares regression model (LLS) is constructed in a piecewise manner to correct the shifts of retention time of some peaks of interest in the chromatograms of various test samples. The results compare favorably with those obtained by a two-point calibrated algorithm. It is shown that performing SCC and LLS on the piecewise clusters of various chromatographic fingerprints is more helpful in practice in revealing their common nature and for characterizing the chemical constituents. This approach holds great potential for facilitating quality control of herbal medicines.     

A compact long-wavelength fluorescence detection system and its application to flow injection immunoassay

A compact and robust long-wavelength fluorescence detection system (LWFDS) has been constructed using a pulsed diode laser as the light source and a photodiode detector. The detection limits for naphthofluorescein (NF) and the cyanine dyes Cy5 and Cy5.5 at pH 8.8, determined using the LWFDS, were 1.0×10⁻¹⁰, 2.3×10⁻¹² and 6.2×10⁻¹¹ M, respectively. These values compared favourably with data from a commercial research grade fluorescence spectrometer. The LWFDS instrument was used as the detector for a competitive heterogeneous flow injection immunoassay for α-interferon with Cy5 as the label. A calibration graph usable over the range 0.5-10 μg ml⁻¹ α-interferon was obtained. The instrument demonstrated its potential for rapid (<200 s per sample) multi-analyte assays and for field monitoring.     

萘酚-亚硝酸根对三聚氰胺的光谱响应及应用

用荧光光谱和紫外可见光谱研究了萘酚-亚硝酸根与三聚氰胺相互作用的性质,考察了溶液酸度对作用体系的影响.在4.1＜pH＜8.6时,三聚氰胺使体系荧光光谱增强,体系对三聚氰胺的线性响应范围为2.0～20 mg/L; 在8.6≤pH≤10.1时,三聚氰胺使体系荧光光谱降低,体系对三聚氰胺的线性响应范围为2.0～60 mg/L...     

钇(Ⅲ)-莫西沙星配合物的荧光性质及分析应用

钇(Y3+)与莫西沙星(MoxifloxacinMXFX)形成的配合物能显著地增敏莫西沙星的荧光强度,据此,建立了测定莫西沙星的新方法。该方法的检出限为8.5×10-10mol/L;莫西沙星的浓度在1.0×10-8～1.0×10-6mol/L范围内与配合物体系的荧光强度呈良好的线性关系。对1.0×10-6mol/L莫西沙星平行测定12次,RSD为1.1%。该法可用于测定尿样中的莫西沙星。对荧光增强机理作了简要的探讨。     

色氨酸-亚硝酸体系荧光性质的研究及应用

本文首次提出了利用亚硝酸氧化色氨酸的荧光反应测定色氨酸的方法。亚硝酸氧化色氨酸,继而在氢氧化钠介质中生成荧光物质,其激发波长和发射波长分别是:λ~e~x=320nm,λ~e~m=392nm。当色氨酸浓度为0.2～1.6μg/mL时,工作曲线呈良好的线性。本方法用于测定蛋白质样品中的色氨酸,结果令人满意。本文还对反应产物的特性进行了研究。     

The fluorescence enhancement effect of Tb-Gd-adenosine triphosphate-phen system and its analytical application

It is found that the fluorescence of Tb-adenosine triphosphate (ATP)-phenanthroline (phen) system can be enhanced by Gd³⁺. The fluorescence enhancement of the Tb-Gd-ATP-phen system is considered to originate from intramolecular and intermolecular energy transfers, and the energy-insulating sheath effect of Gd-ATP-phen complex. In addition, a new energy transfer pathway in Tb-ATP-phen system is proposed. As a mediator, phen can transfer the energy absorbed by ATP to Tb³⁺ through the stacking action between aromatic ring of phen and purine ring of ATP. The proposed method has been used to determine trace amount of ATP. The detection limit is 5.4 × 10⁻⁹ mol/l, which is about 40 times lower than that of the Tb-ATP-phen system. The proposed method is one of the most sensitive fluoremetries of ATP.     

培氟沙星-铽(Ⅲ)-牛血清白蛋白体系的荧光光谱及其应用

在pH 8.2的Tris-HCl缓冲溶液中, Tb3+与培氟沙星(PEFX)形成的配合物受290 nm紫外光激发发出Tb3+的特征荧光峰, 加入牛血清白蛋白(BSA)能大大增强体系的荧光强度, 由此建立了PEFX-Tb3+ 配合物探针测定BSA的方法. 与PEFX-Tb3+二元配合物相比, PEFX-Tb3+-BSA三元体系荧光强度显著增强. 研究了反应的最佳条件, 并对PEFX-Tb3+-BSA荧光增强作用的机理进行了探讨.     

邻氯酚红-Fenton体系对金属离子的光化学传感研究

利用具有高度选择性的光化学传感器来识别和检测金属离子是近年来的一个热点研究领域~([1]),因为被测物引起的体系颜色变化直观可见且灵敏,这方面已有许多成功的报道~([1-5]).邻氯酚红(CPR)是一种氯取代的三苯甲烷类酸性染料,除了纤维染色之外已被用于蛋白质和药物测定~([6]).     

吩噻嗪类化合物的光谱特性及其在生物分析中的应用

研究了MV的流体荧光和固体基质室温磷光特性,并用光谱法初步探讨了MV与DNA的相互作用.     

Terbium-sensitized fluorescence method for the determination of pazufloxacin mesilate and its application.

A simple, rapid and highly sensitive fluorometric method for the determination of pazufloxacin mesilate (PZFX) is described. It is based on the formation of the complex [Tb(PZFX)2](3+), which shows the intensive characteristic bands of Tb3+. Optimum conditions for the determination were investigated. Under the optimum experimental condition, the fluorescence intensity responds linearly to the PZFX concentration in the range of 2.0 x 10(-8) - 5.0 x 10(-6) mol/l with a detection limit of 6.2 x 10(-9) mol/l. The method has been successfully applied to the determination of PZFX in urine and serum samples.     

A fluorescence detection system for the analytical ultracentrifuge and its application to proteins,nucleic acids,and viruses

A fluorescence detection system was developed for the analytical ultracentrifuge Spinco model E. Fluorescence is excited by a laser beam which is focussed into the cell and illuminates an area with a dimension of 60 m in radial direction. For scanning the laser beam is moved in radial direction. After passing the cell, the laser beam is quenched by a carbon light trap and a set of optical filters. Fluorescence emission intensity is monitored by a photomultiplier located behind the light trap and the set of filters. The sensitivity of the detection system was tested by applying it to the sedimentation analysis of proteins and nucleic acids. Bovine serum albumin (BSA) was covalently labelled with the fluorescence-dye fluorescein-isothiocyanate (FITC), and its sedimentation coefficient could be determined even if BSA was analyzed in a concentration as low as 10^–10 M. Nucleic acids were labelled non-covalently by the intercalating dye ethidium bromide. Only 8 ng RNA were needed for the determination of the sedimentation coefficient. The particular advantages of the fluorescence detection system were exploited for the establishment of a new method for quantitative virus detection. To tobacco mosaic virus (TMV) a monoclonal anti-TMV antibody from mouse was bound, and to this a second, anti-mouse antibody that carried the fluorescence-label FITC was attached. Either by UV-irradiation or by incubation with glutaraldehyde, the first antibody was covalently crosslinked to TMV, and the second antibody to the first. In CsCl density centrifugation with fluorescence detection as little as 3.2 ng virus/80 l or 6×10⁸ virus particles/ml were recorded in a well expressed band at the corresponding buoyant density. Tenfold lower concentration would result still in a significant band. The sensitivity compares well with those of the most advanced techniques from immunology. Due to the specific labelling of viruses by antibodies it will be possible to carry out quantitative physical characterization of virus containing samples without purifying the virus. Future applications of the fluorescence detection system and of the virus detection technique are discussed.This paper was presented at the VI. Symposium on Analytical Ultracentrifugation, Marburg, FRG, February 16–17, 1989.     

Effect of gold nanoparticle as a novel nanocatalyst on luminol-hydrazine chemiluminescence system and its analytical application

In this work the catalytic role of unsupported gold nanoparticles on the luminol–hydrazine reaction is investigated. Gold nanoparticles catalyze the reaction of hydrazine and dissolved oxygen to generate hydrogen peroxide and also catalyze the oxidation of luminol by the produced hydrogen peroxide. The result is an intense chemiluminescence (CL) due to the excited 3-aminophthalate anion. In the absence of gold nanoparticles no detectable CL was observed by the reaction of luminol and hydrazine unless an external oxidant is present in the system. The size effect of gold nanoparticles on the CL intensity was investigated. The most intensive CL signals were obtained with 15-nm gold nanoparticles. UV–vis spectra and transmission electron microscopy studies were used to investigate the CL mechanism. The luminol and hydroxide ion concentration, gold nanoparticles size and flow rate were optimized. The proposed method was successfully applied to the determination of hydrazine in boiler feed water samples. Between 0.1 and 30 μM of hydrazine could be determined with a detection limit of 30 nM.     

Photoconversion of o-hydroxycinnamates to coumarins and its application to fluorescence imaging

(E)-o-Hydroxycinnamates were synthesized and their photochemical behavior was investigated in liquid and solid states. It was confirmed by ¹H NMR spectroscopy that the (E)-o-hydroxycinnamates converted into the corresponding coumarins via (Z)-o-hydroxycinnamate intermediates. The photoconversion was greatly accelerated in the presence of p-toluenesulfonic acid. The optical properties of the cinnamates were compared with those of the corresponding coumarins. Fluorescence imaging was successfully accomplished by photoirradiation of PMMA films containing the cinnamates.     

A comparative study of LED-induced fluorescence and laser-induced fluorescence in SDS-CGE: application to the analysis of antibodies

LEDs present an alternative to lasers in LIF detection with CE, resulting in LED-induced fluorescence (LEDIF). LEDs are much less expensive, consume less energy and are more stable. In addition, LED light sources allow a greater range of wavelengths to better match the maximum wavelength for the fluorescence of the dye. Antibodies were largely studied in SDS capillary gel electrophoresis (SDS-CGE) and LIF detection with different dyes to label the proteins. In this work, our goal is to show that LEDs can advantageously replace lasers. We used 5-carboxytetramethylrhodamine succinimidyl ester (5-TAMRA.SE), 3-(2-furoyl)-quinoline-2 carboxaldehyde (FQ), and naphthalene-2,3-dialdehyde (NDA) to label IgG and we compared the LIF sensitivity with that obtained from LEDIF. We measured that the LOD values of LEDIF are identical to that obtained with the wavelength equivalent laser, and for 5-TAMRA.SE analysis, LOD values are about six times better than when the classical 488 nm laser was used.     

一种检测肼的纳米粒子探针及其生物成像应用

肼是一种广泛使用的化工原料,但它也是一种有毒化学品,对人类健康和环境安全有着严重威胁.因此,开发一种方便、快速检测肼的方法具有重要的意义.本文制备了一种芘甲醛纳米粒子探针,其能和肼快速反应,从而使探针的荧光信号发生变化,实现对肼的荧光检测.该探针检测肼具有高选择性和灵敏度,并成功地应用于HeLa细胞和斑马鱼中肼的成像.     

Photochemical fluorescence enhancement of the terbium-lomefloxacin complex and its application

The sensitized fluorescence intensity of the terbium ion (Tb(3+)) can be notably enhanced after the Tb(3+)-lomefloxacin(LFLX) complex system was irradiated by 365nm ultraviolet light. A photochemical reaction occurs to the irradiated Tb(3+)-LFLX complex. A new Tb(3+)system with intense fluorescence is obtained. On this basis a new sensitive and selective photochemical fluorimetry for the determination of LFLX was established. Under the optimal experimental conditions, the linear range of the determination is 2.0-500x10(-8) mol l(-1) for LFLX, and the detection limit is 6.0x10(-9) mol l(-1).Without any pre-treatment the recoveries of LFLX in human urine and serum were determined.     

Effect of backing metals in the X-ray fluorescence spectral analysis of metal films and its application

Summary The enhancement effect of the backing metal on the x-ray intensity of an element in a film has been studied. This effect is dependent on the wave length of the x-ray absorption edge of the element in the film. In the case of nickel film, the infinite thickness at which this effect is lost is about 20, and the infinite thickness is independent on the kind of backing metals. It has also been recognized that this enhancement effect is convenient for increasing the x-ray intensity of small amounts of an element. The application of this effect has been demonstrated for the determination of small amounts of nickel and cobalt, which were concentrated in an organic precipitate.

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Zusammenfassung Die verstärkende Wirkung des Grundmetalls auf die Röntgenstrahlenintensität eines Elementes in einem Überzugsfilm wurde untersucht. Diese Wirkung ist abhängig von der Wellenlänge der Röntgenabsorptions-kante des Elementes im Überzug. Im Falle eines Nickelüberzugs beträgt die Dicke, bei der diese Wirkung aufhört, etwa 20. Diese Dicke ist unabhängig von der Art des Grundmetalls. Die Erscheinung kann zur Erhöhung der Röntgenfluorescenzintensität kleiner Mengen eines Elementes benutzt werden. Als Anwendungsbeispiel wird die Bestimmung kleiner Mengen Nickel und Kobalt beschrieben, die in einem organischen Niederschlag konzentriert wurden.

     

Electrochemiluminescence detection system for microchip capillary electrophoresis and its application to pharmaceutical analysis

We describe an efficient and easily fabricated electrochemiluminescence detection system for microchip capillary electrophoresis. A 300-μm-diameter platinum disc working electrode was embedded in a titanium tube which provides an adequate holding for working electrode and acts as counter electrode. We also have designed a simplified detection cell with a guide channel for the electrode. The integrated working-counter electrode can be easily aligned to the outlet of the separation channel through the guide channel. The functionality of the system was demonstrated by separation and detection of proline and tripropylamine. The response to proline is linear in the range from 5 μM to 5,000 μM, and the detection limit is 1.0 μM (S/N?=?3). The system was further applied to the determination of chlorpromazine hydrochloride in pharmaceutical formulations. The system is believed to have potential applications in pharmaceutical analysis.