The present work describes a new HPLC method and a new spectrophotometric method for the simultaneous determination of ethinyl estradiol (EE) and levonorgestrel (LNG) in their binary combination. In LC method, Nucleosil C8 column with a mobile phase composed of acetonitrile-water (90:10, v/v) with UV detection at 225 nm were used for the analysis of ethinyl estradiol-levonorgestrel combination....

Four methods were developed for simultaneous determination of metoprolol and felodipine without previous separation. In the first method both drugs were determined using first derivative UV spectrophotometry, with zero crossing measurement at 222 and 235 nm for metoprolol and felodipine, respectively. The second method depends on first derivative of the ratios spectra by measurements of the amp...

This is a review of analytical methods, such as spectrophotometry, derivative spectrophotometry and various chromatographic (gas chromatography-GC, high-performance liquid chromatography-HPLC, thin-layer chromatography-TLC, high-performance thin-layer chromatography-HPTLC, liquid chromatography-tandem mass spectrometry-LC-MS, microchip electrophoresis-MCE, capillary electrophoresis-CE) and elec...

Sensitive and specific methods are needed for measuring human exposure to carcinogens. Synchronous fluorescence spectrophotometry can be used to measure fmol of aflatoxins, their metabolites, and DNA adducts. Computer-assisted analysis of spectra of these agents obtained by synchronous fluorescence spectrophotometry can be displayed as contour maps which are highly specific for each agent. Indi...

Stable water soluble surfactant coated CdSe nanocrystals with trioctylphosphine (TOP) were obtained by a process of dynamic surface coating with cationic, anionic, and non-ionic surfactants. The surfactant-coated CdSe/TOP nanocrystals were characterized by complementary techniques of UV-VIS and photo-luminescence spectrophotometry, as well as by means of a capillary zone electrophoretic techniq...

A water-soluble carbodiimide has been used to promote the formation of amide bonds between carboxyl residues on cytochrome b5 and lysyl residues on cytochrome bg reductase. The visible and UV absorption spectrum of the purified cross-linked complex was identical with the sum of the spectra of the individual enzymes, and the average apparent molecular weight of the complex, determined by sodium ...