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91.
The separation of racemic benoxaprofen into the two benoxaprofen enantiomers by preparative high-performance liquid chromatography and the application of the activated enantiomers as derivatization reagents for the simultaneous stereoselective determination of chiral amines in biological material is described. Activated (+)- and (-)-benoxaprofen are both shown to be very sensitive and stable chiral fluorescence markers, applicable to thin-layer chromatography as well as to high-performance liquid chromatography. 相似文献
92.
Biosensors for environmental pollutants and food contaminants 总被引:4,自引:0,他引:4
Baeumner AJ 《Analytical and bioanalytical chemistry》2003,377(3):434-445
This review article provides an overview of the most recent literature on biosensors for environmental pollutants and food contaminants. Due to the large number of publications, only papers published between 2000 and January 2003 were considered. Also, while not all of the published literature could be reviewed here, over 200 references are cited to provide a good overview of research undertaken in the last two years. Older publications are covered by a number of earlier review articles. This article provides an introduction into the field including specific consideration of the application areas, describes the typical biosensor assay format used, and is subsequently structured according to the biorecognition elements used (i.e., nucleic acids, enzymes, whole cells, tissue and whole organisms, antibodies and receptors, and biomimetic materials). In addition, a section on microbiosensing systems is provided. Since only very few microbiosensors with applications in environmental and food systems have been published, enabling technology is also covered in this article.Abbreviations BOD biological oxygen demand - cfu colony forming units - DNP dinitrophenol - GFP green fluorescent protein - NASBA nucleic acid sequence-based amplification - PCR polymerase chain reaction - ppt parts per trillion - QCM quartz crystal microbalance - SPR surface plasmon resonance 相似文献
93.
Zusammenfassung In dieser Arbeit wurden Schlußfolgerungen über den simultanen Verlauf der beiden Reduktionsphasen von Resazurin überprüft.Weiters wurden Bedingungen für die quantitative titanometrische Bestimmung von Resazurin und seiner Derivate ermittelt.
Mit 4 Abbildungen 相似文献
The conclusions about the simultaneous course of reduction of Resazurin to Resorufin and Resorufin to Dihidroresorufin were verified in this work.The conditions for the quantitative titanometric determination of Resazurin and its derivatives were found.
Mit 4 Abbildungen 相似文献
94.
Studies of dispersion patterns in nonsegmented streams, flowing through narrow open tubes, show that it is possible to obtain highly reproducible concentration gradients within a sample zone injected into the moving stream. By varying the geometry of the flow path, low, medium and high dispersion patterns can be achieved; the high dispersion pattern forms the basis for a new approach to continuous flow titrimetry. In this type of titration, discrete samples are passed through a gradient device and are then mixed with a continuously flowing stream of titrant of fixed concentration. The new technique has been tested for potentiometric as well as spectrophotometric end-point indication. A simple one-channel system allows titrations to be performed automatically in less than 1 min. 相似文献
95.
Maria Merces Marques C. Costa F. Lemos F. Ram?a Ribeiro A. R. Dias 《Reaction Kinetics and Catalysis Letters》1997,62(1):9-15
In this paper we present a kinetic approach to the analysis of steady-state homogeneous Ziegler-Natta polymerization activity
data. The influence of the number of monomeric species that are coordinated to the active site on the apparent rate law is
discussed and the equations are fitted to the experimental results. 相似文献
96.
Fausi?RassoulEmail author Heinz?L?ster Volker?Richter 《Monatshefte für Chemie / Chemical Monthly》2005,136(8):1501-1507
Summary. L-Carnitine, L-(−)-β-hydroxy-γ-trimethylaminobutyrate, plays an important role as a factor necessary for the transport of long-chain fatty acids into the mitochondria. In order to investigate the influence of L-carnitine on hyperlipidaemias, the experimental model of the sucrose-induced hypertriglyceridaemia of the rat was used. In these experiments L-carnitine in the dose of 11 mg per day and 100 g body weight (over the period of 1 week) was able to antagonize the sucrose-induced hypertriglyceridaemia and the increase of serum free fatty acid level in female rats of the Wistar strain. Carnitine administration did not change the activities of lipogenic enzymes and fatty acid synthesis in the liver. However, L-carnitine increases the rate of hepatic fatty acid oxidation. Our results indicate a hypotriglyceridemic and free fatty acid lowering effect of L-carnitine, and suggest the use of this compound in the therapy of hyperlipidaemias. 相似文献
97.
E. Havránek A. Bumbálová J. Čižmárik 《Journal of Radioanalytical and Nuclear Chemistry》1984,85(1):21-31
The applicability of two nuclear analytical methods for the determination of hepatacaine hydrochloride in solution was studied, i. e. radionuclide X-ray fluorescence analysis and radiometric titrations based on precipitate formations. Methods used were evaluated on the basis of obtained sensitivity values. 相似文献
98.
The rapid determination of protein in plant material based on spectrophotometric determination of amino acids in protein hydrolysates with trinitrobenzenesulfonic acid has been adapted to flow injection analysis. With the manifold described, a routine sampling rate of 120 samples/h is possible, though this, as well as sensitivity, can easily be varied. The method was calibrated against the Kjeldahl method and a good correlation was obtained between the two methods over a wide range of protein values for beans. 相似文献
99.
The encapsulation and fractionated release of nucleic acids on vesicular packing (VP) materials have been investigated. The earlier described dependence of the permeation of nucleic acid molecules through the vesicle membranes on the salt concentration is a necessary precondition for both encapsulation and fractionation. Encapsulation is achieved by applying a suitable sample onto a VP column that has been equilibrated with a high-salt buffer. In that buffer the sample molecules are permeable. Immediately after sample application, elution is started with a low-salt buffer, from which the sample molecules are excluded. At the front between the two buffers the permeability changes, and some of the sample molecules distributed inside the vesicles cannot pass through the membranes. These encapsulated molecules can be released by increasing the salt concentration in the eluent. If the encapsulated nucleic acid sample is polydisperse, a stepwise or linear increase in the salt concentration leads to a fractionated release. The fractions obtained differ in their molecular size composition. 相似文献
100.
A method for the quantitative analysis of tricyclic antidepressants in the serum of psychiatric patients is described. The method can be used for determining amitriptyline, nortriptyline, imipramine, demethyllimipramine, clomipramine, demethylclomipramine, trimipramine and protriptyline. The method consists in a series of extraction steps followed by gas chromatography with flame-ionization detector. The drugs are determined in their native state. The internal standard method is used for the quantitation. 相似文献