Abstract:
The present invention provides a fluorescent HPLC assay for detecting the presence and/or measuring the level of 20-hydroxyeicosatetraenoic acid (20-HETE) and other P-450 metabolites of arachidonic acid in a sample. P-450 metabolites of arachidonic acid are first extracted from the sample and then labeled with 2-(2,3-naphthalimino)ethyl trifluoromethanesulfonate. The labeling reaction is catalyzed by N,N-diisopropylethylamine. Next, the labeled P-450 metabolites are separated on a 4.5 X 250-mm, 5 mu M particle size C18 reverse-phase HPLC column using a mobile phase of methanol:water:acetic acid (82:18:0.1, v/v/v) and an isocratic elution at a rate of about 1.3 ml per minute. Fluorescence intensities of the column eluent are monitored by a fluorescence detector. Quantitation of P-450 metabolites in a sample can be made by using an internal standard.
Abstract:
The present invention relates to multi-phase protein separation methods capable of resolving and characterizing large numbers of cellular proteins, including methods for efficiently facilitating the transfer of protein samples between separation phases. In particular, the present invention provides an automated system for the separation, identification, and characterization of protein samples. The present invention thus provides improved emthods for the analysis of samples containing large numbers of proteins.
Abstract:
The present invention provides molecular weight markers for accurate determination of the molecular weight of glatiramer acetate and other copolymers. The present invention further provides a plurality of molecular weight markers for determining the molecular weight of glatiramer acetate and other copolymers which display linear relationships between molar ellipticity and molecular weight, and between retention time and the log of the molecular weight. The molecular weight markers also optimally demonstrate biological activity similar to glatiramer acetate or corresponding copolymers and can be used for treating or preventing various immune diseases.
Abstract:
An analytical method is disclosed for quantitative determination of an Iceland moss herbal preparation in a herbal product, wherein ribitol and/or arabitol is used as an analytical marker.
Abstract:
A closure device for gas-tightly closing the opening of a vial which in use contains a liquid or solid material and sufficient headspace volume for performing off-line or automated headspace microextraction under vacuum conditions. The closure device allows for the air-evacuation of the sample container through a cavity with a seal in the presence or absence of the sample and maintains the low-pressure conditions for extended times and during handling of low or high-capacity extracting units. The methods are for off-line or automated headspace microextraction under vacuum conditions, so that the extracting unit with analytes can be conveniently analyzed by means of an analytical instrumentation such as gas chromatography, gas chromatography-mass spectrometry, liquid chromatography, and/or liquid chromatography-mass spectrometry.