Fast analytical methodologies are mandatory for large scale metabolic profiling. Here, we present a thorough evaluation of different column chemistries in combination with different mobile phases for fast LC-MS urinary metabolic profiling. Three porous HILIC materials were investigated, next to core-shell C18-, XB-C18- and PFP-RPLC material. The performance of the selected column chemistries wa...

Ten new polyhydroxyolean-12-ene pentacyclic triterpenoidal saponins, named rogchaponins 1-10, were isolated from the methanolic extract of the roots of Camellia sinensis by a series of chromatographic methods (silica gel flash column and C18 MPLC followed by C18 HPLC). Their structures were established by 1D and 2D-NMR techniques along with IR and HR-TOF-MS. Rogchaponins R4 ( 4) and R5 (5) show...

The performance of isocratic separations of 11 pollutant phenols (PP) using monolithic (Chromolith RP-18e) and conventional reversed-phase 5 microm (Luna and Purospher C18) and 4 microm (Synergi C12) particulate size columns, selected from high purity silica materials, has been compared. The separations have been optimized based on a previously optimized separation in which a reversed-phase C18...

This paper describes the development of a method for the simultaneous determination of ten anticoagulant rodenticides (coumafuryl, warfarin, pindone, coumatetralyl, coumachlor, difenacoum, bromadiolone, brodifacoum, chlorophacinone and flocoumafen) in the liver and kidney based on column-switching liquid chromatography coupled with heated electrospray ionization tandem mass spectrometry. The si...

Isolated five known iridoids glycosides (Scrophuloside A, Harpagoside B, 5-hydroxyloganin, 8-O-acetylharpagide and 6-O-methyl,1-glucopyranosyl catalpol), one phenyl ethanoid glycoside (Verbascoside) and a phenyl ethanol amine (2-(4-Chlorobenzyl amino) ethanol) compound from the methanolic extract of aerial parts of Scrophularia oxysepala using by high performance liquid chromatographyare based ...

A reversed-phase high performance liquid chromatography (HPLC) technique was developed for the analysis of sphingoid bases as their biphenylcarbonyl derivatives. The sphingoid bases (0.3-500 nmol) obtained from sphingolipids after hydrolysis were quantitatively derivatized with biphenylcarbonyl chloride at room temperature for 90 min. After removal of excess reagent by partitioning, the derivat...

: Friesian-type dairy cows were milked with different machine settings to determine the effect of these settings on teat tissue reaction and on milking characteristics. Three teat-cup liner designs were used with varying upper barrel dimensions (wide-bore WB = 31.6 mm; narrow-bore NB = 21.0 mm; narrow-bore NB1 = 25.0 mm). These liners were tested with alternate and simultaneous pulsation patter...

Column selection in reversed-phase liquid chromatography is still not a straightforward process. In this study, we have evaluated and compared the performance of several traditional C18 phases with polar-modified phases and found distinct differences in the chromatographic behavior between two groups, as well as a high degree of variability within each group. The polar-endcapped phases exhibit ...

"Hydrophobic chromatography", which is a variation of reverse phase chromatography, is applicable to the analysis of cephalosporin C derivatives, especially in fermentation broths. Unfortunately, there are no commercial C18 columns which are entirely suitable for this class of compounds. For this reason C18 columns were prepared by an in-situ bonding technique and were optimally designed for ce...