Retention Of Aromatic Hydrocarbons Research Articles

Front Cover: A thermodynamic study of capillary electrochromatographic retention of aromatic hydrocarbons on a lauryl acrylate porous polymer monolithic column with measured phase ratio

Front Cover: A thermodynamic study of capillary electrochromatographic retention of aromatic hydrocarbons on a lauryl acrylate porous polymer monolithic column with measured phase ratio

Comparison of the Retention and Separation Selectivity of Aromatic Hydrocarbons with Polar Groups in RP-HPLC Systems with Different Stationary Phases and Eluents.

In this manuscript, the retention of aromatic hydrocarbons with polar groups has been compared for systems with various nonpolar columns of the types from C3 to C18 and different mobile phases composed of methanol, acetonitrile, or tetrahydrofuran as modifiers. The selectivity separation of the solutes in systems with different adsorbents, when one eluent modifier is swapped by another, has been explained, taking into account molecular interactions of the solutes with components of the stationary phase region (i.e., extracted modifier depending on the chain length of the stationary phase).

Effect of temperature on the retention of aromatic hydrocarbons with polar groups in binary reversed-phase TLC

R M (log[(1 − R F )/ R F ]) values at different temperatures have been compared for aromatic hydrocarbons with different functional groups in reversed-phase thin-layer chromatography with aqueous binary mobile phases containing methanol, acetonitrile, or tetrahydrofuran. Considerable retention and selectivity variations were observed among the systems investigated. Separation of the solutes at different temperatures can be advantageous, because of these selectivity changes and the shortening of the development time. A horizontal DS-chamber has been developed for performing chromatogram development with temperature control.

Quadrupolar Effects on the Retention of Aromatic Hydrocarbons in Reversed-Phase Liquid Chromatography

Because of their large molecular quadrupole moments, aromatic hydrocarbons can give rise to strong electrostatic interactions with polar molecules such as acetonitrile and water. Such interactions may have some significant effects on the retention and separation of the aromatic compounds in reversed-phase liquid chromatography. We report here an experimental investigation of these effects in which we studied the retention behavior of a series of aromatic hydrocarbons in comparison with that of aliphatic hydrocarbons which have no appreciable quadrupole moments. The elution order of benzene, cyclohexane, and n-hexane was determined and shown to follow inversely the increasing magnitude of the molecular quadrupole moments. A linear dependence of retention on molecular polarizability was observed for both the aliphatics and aromatics, the latter being consistently less retained than the former under the same chromatographic conditions. The molecular polarizability and quadrupole moment were regressed as independent variables against the logarithmic retention factors of both the aliphatic and aromatic solutes, and an excellent correlation was found with all five different chromatographic systems studied. These results clearly show that, while the retention of aromatic hydrocarbons is primarily governed by the dispersion interactions with the nonpolar stationary phase, the electrostatic interactions of the aromatic solutes with the polar mobile phase act to reduce the retention and thus contribute favorably to the control of the relative retention and selectivity in reversed-phase liquid chromatography.

Toluene polymer as a new stationary phase in reversed-phase column liquid chromatography

The toluene polymer adhesively sprayed on the surface of silica gel (TP Si100) was used as the packing in reversed-phase liquid column chromatography. The effect of the thickness of the polymer layer covering the silica gel surface on the retention of aromatic hydrocarbons was determined. Retention of aromatic hydrocarbons and phenol on the column packed with TP Si100 is shorter than on a column packed with ODS Si100. Selectivity of the column packed with TP Si100 for phenol, toluene and naphthalene vs. benzene is higher than of a column packed with ODS Si100. Columns packed with TP Si100 were used for the separation of condensed-rings aromatic hydrocarbons and phenols.

The effect of some modifiers on the retention of aromatic hydrocarbons on untreated silica gel

The retention parameters of benzene, naphthalene; anthracene and phenanthrene on untreated silica gel were determined in the presence of four modifiers: 1-methyl-2-pyrrolidone (MP), 4-formyl morpholine (FM), γ-butyrolactone (BL) and sulfolane (SF). Better column performance was found in the case of FM and MP only.

Changes in the volatile hydrocarbon content of Prudhoe Bay Crude Oil treated under different simulated weathering conditions

Changes have been determined in the concentrations of volatile saturate and aromatic hydrocarbons in Prudhoe Bay Crude Oil (PBC) weathered under three different simulated environmental conditions. A combination of light and water sprayed upon the surface of the oil produced the largest relative decreases in volatile saturate and most aromatic hydrocarbons. After 24 days, detectable amounts of monoaromatic hydrocarbons were absent in all three weathered oils, as were the saturate hydrocarbons from C 8 to C 10. Retention of aromatic hydrocarbons appeared to be related to molecular weight, as enrichments of triaromatics (phenanthrenes) were observed in weathered PBC relative to the original crude oil. These data are discussed with respect to effects resulting from spilled oil impacting benthic organisms residing in intertidal and shallow subtidal communities.