Gas—solid Chromatographic separations of petroleum compounds and distillates on lithium chloridecoated silica

Abstract

Gas—solid Chromatographic separation of petroleum-derived compounds and distillates on column packings of lithium chloride-coated diatomaceous silica and porous silica beads have been evaluated. The required operating temperatures and efficiencies of separation for most of the investigated saturated hydrocarbons, aromatics and sulphur- and oxygen-containing compounds on these packings were comparable with those achieved by gas—liquid Chromatographic separations. The retention values are discussed in terms of specific and non-specific interactions to show how compounds of similar boiling points are separated on the lithium chloride-coated silica columns according to chemical structure. These column packings are thermally stable, and can be used for type separations of highboiling petroleum fractions without any of the ‘bleeding’ problems that attend the use of polar stationary liquid phases and which can contaminate further analyses, especially when mass spectrometry is used. Examples of such separations, prior to mass spectrometry, are given.