BACKGROUND In-hospital hypovitaminosis C is highly prevalent but almost completely unrecognized. Medical awareness of this potentially important disorder is hindered by the inability of most hospital laboratories to determine plasma vitamin C concentrations. The availability of a simple, reliable method for analyzing plasma vitamin C could increase opportunities for routine plasma vitamin C ana...

A capillary electrophoretic method (CE) with ultraviolet absorption detection for baclofen in human plasma was developed. The separation was obtained by CE with 50 mM borate buffer at pH 9, followed by detection with an ultraviolet detector at 225 nm. The plasma samples were deproteinized with acetonitrile to remove proteins and to induce sample stacking. With stacking, the limit of detection (...

The purpose of this research was to determine mandelic, phenylglyoxylic, hippuric, o-, m- and p-methylhippuric acids, the six urinary metabolites of styrene, toluene and xylene by high performance liquid chromatography (HPLC). These metabolites were extracted in an acid medium, transferred into a basic solution and back extracted again using ethyl acetate, and the organic phase was evaporated t...

Dispersive liquid-liquid microextraction method (DLLME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine thiamine (B1), nicotinamide (B3) and pyridoxine (B6) in sour cherry juice. This method was rapid, simple and sensitive. Separation was accomplished using a C18 column. The optimum chromatographic conditions were found to be: mobile ph...

with amperometric detection. It has been shown elsewhere that the selectivity of this method is sufficient to separate the potential organic impurities; that is, synthesis byproducts and a specified degradation product from the drug substance (3). The objective of this article is to demonstrate that this method’s suitability for stability testing can be evaluated easily by performing HPLC with ...

General chemical synthesis methods. Anhydrous solvents were obtained commercially. Solvents required for oxime ligation coupling reactions were distilled from 2,4-dinitrophenylhydrazine immediately prior to use. Air-sensitive reactions were carried out under Ar. Thin layer chromatography (TLC) was performed on aluminium sheets coated with 60 F254 silica. Flash column chromatography was performe...

The development of a sensitive automated method for residue control of oxytetracycline (OTC) in cured meat (soudjouk) is described. The principle steps involve the extraction of OTC from cured meat in the presence of citric acid with nitric acid, methanol and de-ionized water, and then the determination by HPLC. In HPLC, Hypersil BDC C18 column was used and OTC was separated at 24◦C using a mob...

Isolation and purification of the active principle within natural compounds plays an important role in drug development. MS (mass spectrometry) is used as a detector in HPLC (high performance liquid chromatography) systems to aid the determination of novel compound structures. Clustering techniques provide useful tools for intelligent data analysis within this context. In this paper, we analyse...

Metabolite identification is a key step for metabonomics study. A fully automated hyphenation of HPLC-diode-array detector (DAD) mass spectrometry (MS) solid phase extraction (SPE)-NMR spectroscopy (HPLC-DAD-MS-SPE-NMR) is one of the most efficient methods to determine the structure of a given unknown metabolite in a complex mixture (metabonome) and hence represents one of the most important an...

A column-switching high-performance liquid chromatography (HPLC) system for the determination of phosphopeptides has been developed. The method is based on the selective adsorption of phosphopeptides on a titania (TiO2) precolumn and successive HPLC separation of the phosphopeptides on an anion-exchange column with a UV detector (215 nm). The recoveries of phosphopeptides were tested using auth...