Thin-layer chromatographic separation of the common bile acids and their taurine and glycine conjugates in chloroform-methanol-ammonia is reported. An alkaline system offers advantages for the separation and nondestructive staining of bile acid conjugates.

Simulated moving bed (SMB chemical mixtures. This paper presents an almost plug knowledge about the adsorption properties is the basis to control the position of the adsorption and desorption fronts estimated on-line enabling the compensation of initial parameter discrepancies aging or temperature fluctuation. numerical simulation for two case studies relative to the separation of cyclopentanon...

In this work, an improved single-column chromatographic (ISCC) separation process is proposed. The term `improved' refers to both conceptual and physical modifications compared to the available single-column processes, including a novel fraction collection scheme and allowing overlapped peaks from adjacent cycles. Also the fraction collection mechanism was modified in order to facilitate online...

Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant so...

Principle Chromatographic procedures allow a separation of substance mixtures with the aid of a stationary separating phase and a mobile phase. In gas chromatography the mobile phase is a gas. The mobile phase, to which the mixture to be separated is added, transports the substance mixture through the separation column at a constant flow rate. Interactions occur between the mobile phase and the...

In the course of an investigation into the metabolic pathways of nucleotide purines by means of tracer elements, it became necessary to prepare from biological sources pure specimens of adenine and guanine in sticient quantities for analyses in the mass spectrometer. In general, for preparative purposes, use has been made of the insolubility of adenine and guanine under certain strictly specifi...

abstract: In this paper we describe the thin layer chromatographic separation of eight of the most frequently used benzodiazepine derivates (alprazolam, bromazepam, chlorazepate potassium, chlordiazepoxide, diazepam, nitrazepam, oxazepam) and their degradation products after acid hydrolysis. Our aim was not only to develop a simple, rapid and efficient method for their separation but also the o...

A procedure was developed for the separation of pigment fractions in a wild-type Serratia marcescens strain. Separation was achieved by column chromatography and elution with several organic solvents. At least six pigment fractions were obtained from the alumina columns by this technique, whereas only four fractions had been reported previously. Spectral and elemental analyses indicate that, in S.

Synthetic dipeptides comprising mixtures of enantiomers, diastereomers, or sequential isomers were converted into their N-perfluoroacetyl dipeptide esters (perfluoroacetyl: trifluoroacetyl, pentafluoroacetyl, heptafluorobutyryl; ester: methyl, 1-propyl, 2-propyl, 2,2,2-trifluoroethyl) and analyzed by GC-MS on the chiral stationary phases Chirasil-L-Val and Lipodex-E using helium as carrier gas....