Vloeistofchromatografie : korter of langer op het stationaire bed

Vloeistofchromatografie in kolommen wordt toegepast voor de scheiding van mengsels en de kwantitatieve bepaling van de individuele componenten in de vloeistof die de kolom verlaat. De methode is in beginsel bruikbaar voor alle stoffen, die in oplossing kunnen worden gebracht zonder dat daarbij storende reacties optreden

Vloeistofchromatografie : korter of langer op het stationaire bed

Vloeistofchromatografie in kolommen wordt toegepast voor de scheiding van mengsels en de kwantitatieve bepaling van de individuele componenten in de vloeistof die de kolom verlaat. De methode is in beginsel bruikbaar voor alle stoffen, die in oplossing kunnen worden gebracht zonder dat daarbij storende reacties optreden

Study of primary tars obtained by quick pyrolysis of Faulquemont coal

Powd. Faulquemont coal (80-160 m) was heated at up to 1000 Deg/sec in a N stream with exposure times o

Determination of trace amounts of hydroperoxides by column liquid chromatography and colorimetric detection

The sensitive and selective determination of separated compounds in effluents from liquid chromatographic columns can be carried out by continuously adding a suitable colorimetric agent to the column effluent and continuously monitoring the absorbance of the reaction mixture. However, a considerable amount of additional broadening of the chromatographic peaks may occur in these systems, especially if slower reactions make it necessary for longer residence times to be used in the reactors. It is shown how this additional broadening can be reduced to an acceptable level by using packed reactors. Some general characteristics of these reactors are discussed and rules for the optimal design are given. A method is described for the determination of hydroperoxides in reaction mixtures from the oxidation of hydrocarbons. Separations are carried out by adsorption chromatography. In an on-line packed reactor, iodine is formed by hydroperoxides in an acidic solution of sodium iodide, and the absorbance of the reaction mixture is measured at 362 nm. A delay time of 1.5 min at a temperature of 70° in the reactor involved a standard deviation of the residence time distribution of less than 1 sec. Nanogram amounts of hydroperoxides can be determined by means of this colorimetric detector

A quantitative assay of cortisol in human plasma by high performance liquid chromatography using a selective chemically bonded stationary phase

The extraction and subsequent liquid chromatographic analysis of human plasma samples for cortisol is described. Extraction and chromatography are optimized, resulting in a recovery for cortisol of 96% and a detection limit of 1 microgram cortisol in 100 ml plasma. The application of two chemically modified silicas has been evaluated. The specificity of the method was tested by field desorption - mass spectrometry experiments

Mechanisms of separation using the ternary mixture di-chloromethane-ethanol-water in high-performance liquid chromotography

The mechanisms of separation using the ternary system dichloromethane— in high-performance liquid chromatography were investigated. The use of an eluent saturated with water results in a separation based on partition of the component between a polar stationary phase, held in the pores of the porous support, and an apolar mobile phase percolating through the packed bed. Selective separations according to an adsorption mechanism are obtained by using an eluent partially saturated with water, corresponding to a point outside the miscibility gap of the three solvents