A study of a simple and sensitive method for the determination of berberine, luguine and sanguinarine in mixtures by normal and synchronous derivative spectrofluorimetry is described. The influence of solvents and other experimental variables is discussed. A three-dimensional plot of both emission-excitation and synchronous spectra obtained by a new software program provides additional informat...

Unusually structure-selective growth of single-walled carbon nanotubes (SWNTs) has been attained using a CVD method with a solid supported catalyst. In this method, CO feedstock disproportionates on silica-supported catalytic nanoclusters of Co that are formed in situ from mixed salts of Co and Mo. The nanotube products are analyzed by spectrofluorimetry to reveal distributions resolved at the ...

A simple approach is described for preparing poly-(ethylene glycol) hydrogel materials with encapsulated seminapthofluorescein (SNAFL)-organophosphorus hydrolase enzyme conjugates. Direct determination of enzyme-catalyzed neurotoxin hydrolysis is provided by the self-referencing, pH-sensitive dye SNAFL-1, whose emission spectrum changes at lambda = 550 in response to pH. Using spectrofluorimetr...

Glu85 in the Escherichia coli thioredoxin, which is localized in the loop between beta4 and beta5, was substituted with the Arg present in the corresponding position in Bacillus acidocaldarius thioredoxin. This suggested that it could play an important role in the structure and thermostability of this protein owing to its involvement in numerous interactions. The effects of the mutation on the ...

an efficient dispersive liquid-liquid microextraction using tetraalkylammonium bromide coated silver nanoparticles (dllme-agnps) prepared in chloroform has been successfully applied as electrostatic affinity probes to the microextraction and preconcentration of terazosin prior to spectrofluorimetry analysis. this technique is based on a ternary system of solvents, where appropriate amount of mi...

a method based on the ultrasound-assisted solidification of floating drop microextraction technique was developed for the spectrophotometric and spectrofluorimetric determination of curcumin in turmeric powder. in this work a small volume of an organic solvent was floated on the surface of an aqueous solution. after sonication the organic solvent is solidified and separated. the effect of extra...