Mammalian cell proteins, modified post-translationally by derivatives of [3H]mevalonic acid, were subjected to methylation and sulfonium salt cleavage reactions previously used to release isoprenoids from cysteine residues in yeast peptides. The labeled isoprenoid extracted into chloroform comigrated with farnesol through a series of chromatography steps including Sep-Pak C-18 fractionation, si...

We present an HPLC method for the determination of amino acids in plasma. The method is based on automated precolumn derivatization of amino acids with o-phthalaldehyde, separation of the derivatives by reversed-phase chromatography, and quantification by fluorescence detection. Complete separation was achieved within 12 min. Total analysis time, including derivatization, chromatography, and re...

−In reversed-phase liquid chromatography (RP-LC), the separation of ionized compounds at neutral pH of the mobile phase is ineffective because these compounds easily become ionized and too hydrophilic to adsorb on the hydrophobic C18 stationary phase. The common method to separate ionized compounds in RP-LC is the usage of the ion pairing agent and the control of pH in the mobile phase. In this...

The bioactive iridoid component catalpol was successfully separated by high-speed countercurrent chromatography with high purity from the partially purified crude extract of Rehmannia glutinosa. A polar two-phase solvent system composed of ethyl acetate-n-butanol-water (2:1:3, v/v/v) was selected by thin-layer chromatography and run on a preparative scale where the lower aqueous phase was used ...

An electric charge-tunable micro-column (CTMC) was developed as a precolumn for reversed-phase capillary chromatography using conductive carbon fibers as the stationary phase. The carbon fibers, which constitute one electrode, are packed into a heat-shrinkable tube, which is attached to a stainless-steel column body. The mobile phase flows into CTMC through a stainless-steel tube that acts as...

Proteins and other macromolecules of interest can be purified from crude extracts or other complex mixtures by a variety of methods. Selective precipitation is perhaps the simplest method for separating one type of macromolecule from another. Most purification methods, however, involve some form of chromatography whereby molecules in solution (mobile phase) are separated based on differences in...

An α-glucosidase inhibitor was developed from Aspergillus oryzae N159-1, which was screened from traditional fermented Korean foods. The intracellular concentration of the inhibitor reached its highest level when the fungus was cultured in tryptic soy broth medium at 27℃ for five days. The inhibitor was purified using a series of purification steps involving ultrafiltration, Sephadex G-25 gel p...

A method is described for the confirmation/identification of a range of commonly misused drugs in urine samples. The method has been used for two years without problems for a range of purposes including hospital/clinic drugs of misuse screening and for toxicology in coroner's cases. Urine samples which have given a positive result on immunochemical screening for a particular drug group or group...

A novel amide stationary phase (ASP) for hydrophilic interaction liquid chromatography (HILIC) has been prepared via the Click chemistry method. It was based on the strategy that the amino group of Asparagine was easily transferred to the corresponding azido group and then clicked onto terminal alkyne-silica gel in the presence of Cu(I)-based catalyst. For the tested polar compounds including n...

A simple, rapid, gradient reversed phase Ultra Performance Liquid Chromatographic method with ultraviolet detection (UPLC-UV) was developed for analysis of Albuterol sulfate and its impurities in Albuterol sulfate inhalation solution pharmaceutical formulation. Chromatography was carried out on a Waters Acquity BEH C18 (1.7μm, 100mm.x 2.1mm) column using 0.02 M Potassium Dihydrogen Orthophospha...