During the course of investigations involving the action of tissue slices on tryptophan, the aqueous medium in which n-kynurenine sulfate had been incubated with kidney slices was found to have acquired a marked bluish violet fluorescence. Subsequent investigation showed that several known metabolites of tryptophan fluoresce when suitably exposed to ultraviolet light. Advantage has been taken o...

The advance in knowledge of clinical disorders involving calcium and bone diseases has resulted in part from the development of assay procedures for the major vitamin D metabolites, but the values of the same samples measured in different laboratories vary considerably. They suggest that the chromatographic purification involved in these assays seems to be a critical step. In this study, we com...

A high-performance liquid chromatographic method has been developed for the quantitative determination of piperacillin in plasma. The compound is first extracted from acid-treated plasma into chloroform: 1-pentanol (3:1) and reextracted into a small volume of an aqueous phase at pH 7, which is injected in the chromatographic column (microgram-Bondapack C18; 10 micrometers). The mobile phase is ...

The instant thin-layer chromatographic method of determining the radiochemical purity of (99m)Tc-tetrofosmin recommended by the manufacturer uses a mixture of acetone and dichloromethane (35:65 v/v) as the solvent and a silica gel (SG) strip as the solid phase. Currently, SG strips are not available commercially and an alternative solid phase is needed. The present study reports that silicic ac...

A green and efficient one-pot three component reaction of 4-hydroxycoumarin or 1,3-dimethylbarbutyric acid, aryl glyoxals and amides (thioacetamide) has been developed in the presence of BF3- SiO2 nanoparticles in water. This method has several advantages such as high to excellent product yields in short reaction time, atom economy, environment friendly, reusable catalyst and no need for chroma...

An isocratic, sensitive and stability-indicating high performance liquid chromatographic (HPLC) method for separation and determination of the related substances of micafungin sodium was developed. The chromatographic separation was achieved on Agilent Zorbax SB-C18 column (250 × 4.6 mm, 5 μm). Forced degradation study confirmed that the newly developed method was specific and selective to the de...

A high-pressure liquid chromatographic method for the determination of norfloxacin or ciprofloxacin concentrations in body fluids was developed and compared with a standard bioassay. The high-pressure liquid chromatographic assay utilizes a reverse-phase C18 column, an internal standard, and fluorescence detection, with reproducibility studies yielding coefficients of variation ranging from 0.6...

Thin-layer chromatographic method, with postchromatographic derivatization, was applied for the purposes of the quality control of pharmaceutical preparations, containing S. officinalis L. extract. Six finished products underwent the analysis: capsules, tablets, two ointments, tincture and finished product being a mixture of ethanolic S. officinalis and Thymi vulgaris extracts. Chromatographic ...

Simple and rapid thin-layer chromatographic methods, using heel or finger-tip blood, are describedthat are suitable for screening for inborn errors of amino acid metabolism. Serum is chromatographed without deproteinizing. A variation of this method utilizes blood impregnated on paper discs for chromatography. These methods are much faster, more sensitive, and provide better resolutionof amino ...

A new chiral liquid-chromatographic method was developed for the enantiomeric separation of ofloxacin with a fluorescence detector. The enantiomers of ofloxacin were baseline resolved on a Chiralcel OD-H (250 mm x 4.6 mm, 5 microm) column using a mobile-phase system containing hexane-ethanol-methanol-acetic acid-diethylamine (70/20/10/0.45/0.05, v/v/v/v/v). The presence of diethylamine in the m...