Quenching method

NEW FLUORESCENCE QUENCHING METHOD FOR DETERMINATION OF COPPER (II) IN WATER... 

Fluorescence quenching methods wits ai omatic complexing reagents are often recommended for copper (II) determination in water. 

The kinetics of the oxidation of Fe(II) by Ce(IV) in aqueous perchloric acid have been studied, using reactant concentrations in the range 10 to 10 M (ref. 242). A quenching method was utilised to monitor the disappearance of Fe(II). The reaction conforms to a 1 1 stoichiometry and is of simple second order, viz. 

Fig. 6.20. Types of assays to visualize lipid trafficking in membranes. (A) Self-quenching method. Here the self-quenching is released upon transfer to unlabeled acceptor membranes that are usually in large excess. (B) FRET assays. Here the donor membrane contains a transferable lipid (green) that is quenched by FRET to a non transferable acceptor lipid (red). Upon transfer to an unlabeled acceptor membrane the green-labeled lipid becomes unquenched. 

T. Ohyashiki, M. Nunomura, and T. Katoh, Detection of superoxide anion radical in phospholipid liposomal membrane by fluorescence quenching method using 1,3-diphenylisobenzofuran. Biochim. Biophys. Acta. 1421, 131-139 (1999). 

DOM derived from soil, fluorescence quenching method, Magee et al. 1991)... 

Gauthier, T.D., Shane, E.C., Guerin, W.F., Seitz, W.R., Grant, C.L. (1986) Fluorescence quenching method for determining equilibrium constants for polycyclic aromatic hydrocarbons binding to dissolved humic materials. Environ. Sci. Technol. 20(11), 1162-1166. 

The most interesting process is, therefore, the flash pyrolysis, because it leads to the maximum yield of the most valuable product, the oil. For this process, the key parameters are the char separation and the vapor residence time (determined by the quenching method). 

Quenching methods, in which the fluorescence of a substance is reduced by the quenching action of an analyte, can also be used in fluorescence analysis. Such methods are particularly well suited to the analysis of gases. 

Furthermore, the quenching of internal residues in proteins by ionic quenchers, although not strong, is quite detectable.(56) A double-quenching method was developed to separate fluorescence quenching parameters characteristic of solvent-exposed and buried fluorophores.(57) The method uses two types of quenchers simultaneously, one type penetrating and the other not penetrating into the protein matrix. 

E. A. Haigh, K. R. Thulborn, and W. H. Sawyer, Comparison of fluorescence energy transfer and quenching methods to establish the position and orientation of components within the transverse plane of the lipid bilayer. Application to the gramicidin A-bilayer interaction, Biochemistry 18, 3525-3532 (1979). 

Exchanging Pair Rate Constant M" s Temp. °C Quenching Method Refer- ence... 

The ALIS quench method for dissociation rate measurement uses little protein and requires no biochemical assay for its implementation, yet the method readily yields quantitative values for the dissociation rates of the protein-ligand complexes. The technique can be used with pools of ligands to provide a quantitative rank ordering of the dissociation rates of all the components of the mixture. Since it is not necessary to know the exact concentrations of the ligands under study, the dissociation rate assessment can be performed using impure compounds, such as unpurified compound mixtures derived from combinatorial chemistry synthesis. The method does not require a foreknowledge of active protein concentration to measure and rank ligands based on their rates of dissociation. As such, the technique is self-contained and does not rely upon an external measure of protein activity as one of its input parameters. 

Refers to that initial period of nonhnear product formation, commencing with the initiation of the reaction and ending when the system is at steady state. Typically, the pre-steady-state phase lasts from milliseconds to a few seconds after mixing reactants. The time course of pre-steady-state rate processes often can be evaluated using stopped-flow, temperature-jump, and mix-quench methods. 

In the time-resolved quenching method, the decay kinetics of the monomer and the excimer emission are monitored in the presence of a micelHzed medium. If the micellar system is viewed as a group of individual micelles with probe occupancies 0, 1, 2, 3, etc., the probabihty of micelles with n probes, Pn, may be related to n, the average number of probes per micelle by Poissonian statistics through relation. 

Living olefin polymerization allows the synthesis of end-functionalized polyolefins if appropriate initiation and/or quenching methods are used. Doi et al. first showed the utility of living olefin-polymerization catalysts for the preparation of end-functionalized polyolefins. They synthesized iodine-, amine-, aldehyde-, hydroxy-, and metha-cryl-terminated PPs using living V-PP species and appropriate reagents. " " ... 

Various NMR spectroscopic techniques have been applied to investigate the conversion of methanol on acidic zeolites in the low-temperature (r<523K) formation of DME and the high-temperature (T>523 K) formation of alkenes and gasoline. Techniques successfully applied were the stop-and-go method under batch reaction conditions 258,259), the pulse-quench method 113), and various flow techniques 46,49,74.207,260 263). This section is a summary of the recent progress in investigations of the mechanism of the MTO process by NMR techniques. 

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