Gas-solid chromatography of polycyclic aromatic and polyphenyl hydrocarbons using salt-modified porous silica beads

Both gas-liquid and gas-solid chromatography have been used in attempts to separate polycyclic aromatic hydrocarbon and polyphenyl class compounds. To date, only limited success has been achieved. This investigation employed porous silica beads, modified by coating the surface with various inorganic salts, as the column packing material. The separations obtained with these columns arise from the differences in bonding forces between the salt-modified silica surface and the aromatic compounds. Thermodynamic and retention data have been calculated for these high boiling compounds, and correlated into a retention index for the prediction of retention volumes, based on the physical and chemical properties of the compounds. The various column efficiencies of the different salt-porous silica bead combinations have boon compiled, thermodynamic parameters of the compounds have been calculated, and the adsorption mechanism of the salt-modified silica beads has been investigated.