A simple reverse phase high-performance liquid chromatographic method for a simultaneous analysis of free, glycine- and taurine-amidated bile acids is described. The resolution of ursodeoxycholic, cholic, chenodeocycholic, deoxycholic, and lithocholic acids, either free or amidated with glycine and taurine, is achieved using a C-18 octadecylsilane column (30 cm length, 4 micron particle size) w...

A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma. Furosemide was used as an internal standard. Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether...

The use of PCR amplification to detect target DNA sequences has many applications in plant genotyping, gene mapping, diagnostics, and diversity assessment. PCR itself is simple to set up, and requires little hands-on time. However, most methods for preparing DNA from plant tissues are time consuming, tedious, and labor intensive. Virtually all require mechanical disruption, such as grinding in ...

The oil-degrading Arthrobacter sp. RAG-1 produced an extracellular nondialyzable emulsifying agent when grown on hexadecane, ethanol, or acetate medium. The emulsifier was prepared by two procedures: (i) heptane extraction of the cell-free culture medium and (ii) precipitation with ammonium sulfate. A convenient assay was developed for measurement of emulsifier concentrations between 3 and 75 m...

A simple, sensitive, selective and reproducible method based on high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/MS) was developed for the determination of a macrolide antibiotic azithromycin in human plasma. The internal standard (roxithromycin) was separated from azithromycin on a Hypersil Gold C18 column, with retention times of 10.71 and 13.67 minu...

the feasibility of extractive reaction of methacrylic acid from aqueous solution using a quaternary amine, tri–octyl methyl ammonium chloride (tomac) as an extractant, was studied. the diluents chosen in the present work belong to different chemical classes, n–butyl acetate, carbon tetrachloride, isoamyl alcohol, methyl isobutyl ketone, and toluene. the effect of initial acid concentration in t...

BACKGROUND Snus is a smokeless oral tobacco product with a significant history of use in Sweden, where it is regulated under food legislation. Users place a small porous sachet or a pinch of loose snus between the upper jaw and cheek for approximately one hour, leading to partial intake of tobacco constituents. To understand user exposure to tobacco, a multi-analyte approach based on the extrac...

The feasibility of extractive reaction of methacrylic acid from aqueous solution using a quaternary amine, tri–octyl methyl ammonium chloride (TOMAC) as an extractant, was studied. The diluents chosen in the present work belong to different chemical classes, n–butyl acetate, carbon tetrachloride, isoamyl alcohol, methyl isobutyl ketone, and toluene. The effect of initial acid concentration in t...

The methods commonly used for precipitating aluminum by 8-hydroxyquinoline from an acetic-acid solution, buffered with ammonium acetate, do not sufficiently define the conditions requisite for complete precipitation. The present article describes a method in which aluminum is precipitated as the oxyquinolate from a solution which has been partially neutralized with ammonium hydroxide, using bro...

The 3 rapid screening methods studied all involved chromatography of partially purified extracts on minicolumns. In one method acetonitrile-water is used to extract aflatoxin from corn and a lead acetate precipitation removes impurities from the extracts. The second method specifies acetone-water as the extracting solvent and ammonium sulfate as the precipitant. The third method is based on ace...