Application of two methods of calculation of solvation descriptor L to estimate C5 -C7 alkenes retention.

The solvation descriptor L for 59 isomers of all C5 -C7 alkenes was calculated using two methods based on additive contributions of particular fragments in the molecule by the method of Havelec and Ševčík and the method of Platts and Butina. These descriptors were used to estimate the gas chromatography retention of alkenes on squalane and polydimethylsiloxane stationary phases. The retention was described better by the Platts-Butina method.

Characterization of sorption mechanisms of solid-phase microextraction with volatile organic compounds in air samples using a linear solvation energy relationship approach.

The linear solvation energy relationship (LSER) model was used to characterize interactions responsible for sorption of volatile organic compounds (VOCs) in air samples on six different solid-phase microextraction (SPME) fibers at 296K and zero relative humidity. The polydimethylsiloxane and polyacrylate fibers sorption data were also modeled at different relative humidities in the range of 10-90% and influence of water vapors on the extraction process is discussed. The LSER equations were obtained by a multiple regression of the distribution coefficients of 14 probe solutes on an appropriate SPME fiber against the solvation parameters of the solutes.

Theoretical and experimental study of recycle capillary gas chromatography with carrier gas propelled by a peristaltic pump.

A new technique of recycle capillary gas chromatography (RCGC) characterized by a very high separation efficiency of more than 10(6) theoretical plates has been developed to solve the problem of separation of isomers with similar physico-chemical properties. The technique replaces the recycle valve by a peristaltic pump that propels the carrier gas. A general model has been developed for description of RCGC characteristics and experimentally verified on the retention behaviour of methane and the separation of a test pair of 3-methyl-1-butene and 2-methylbutane.