A rapid, simple and direct assay procedure based on first-derivative spectrophotometry, using a zero-crossing and peak-to-base measurement at 234 and 324 nm, respectively, has been developed for the specific determination of dextromethorphan HBr and bromhexine HCl in tablets. Calibration graphs were linear with the correlation coefficients of 0.9999 for both analytes. The limit of detections we...

Several intermediates in the reaction of 2-methylglutamate with glutamate decarboxylase from Escherichia coli were detected by stopped-flow spectrophotometry and by rapid-scanning spectrophotometry after conventional mixing. Structures were assigned to intermediates on the basis of kinetic and spectral evidence. In the early stages of the reaction an intermediate with the properties expected of...

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...

Computed tomography fails to ascertain, or exclude, the presence of intracranial haemorrhage in a considerable number of cases, especially in subarachnoid haemorrhage and haemorrhagic infarcts. A number of other methods, including cerebrospinal fluid spectrophotometry and cytology have, therefore, been tested to define their diagnostic efficacy in 25 cases of confirmed intracranial haemorrhage ...

Zinc is determined in neutrophils and lymphocytes (isolated from whole blood on discontinuous gradients of Ficoll-Hypaque) and in microliter quantities of plasma and erythrocytes by flameless atomic absorption spectrophotometry with greater sensitivity than with conventional flame atomic absorption spectrophotometry. Before analysis, neutrophils and lymphocytes are digested with nitric acid and...

A method for determination of alendronate sodium salt, clodronate disodium salt and etidronate disodium salt in pharmaceutical formulation by direct UV-spectrophotometry and/or first and second derivative UV-spectrophotometry via complex formation with Cu (II) ions is described. The calibration graphs are linear in the range 25-600 mmol/L for all the investigated compounds. No interference was ...

a method to quick detect concentration of lecithin in eggs, namely microwave digestion spectrophotometry, was established in this research. the homogenate of eggs was treated with absolute ethanol to eliminate phosphate protein in eggs which could possibly affect concentration of lecithin examined. a sample then received a new way of pre-treatment, called microwave digestion, before uv-vis spec...

The near-infrared (NIR) spectral region (700-2500 nm) is a fertile source of chemical information in the form of overtone and combination bands of the fundamental infrared absorptions and low-energy electronic transitions. This region was initially perceived as being too complex for interpretation and consequently was poorly utilized. Advances in chemometric techniques that can extract massive ...