No abstract

No abstract

Four adsorbents based on silica gel Si100 with chemically bonded cyclohexane have been prepared as stationary phases for gas chromatography. The concentrations of cyclohexane radicals thus bonded with the silica gel surface were 1.35, 3.35, 4.17 and 6.02 μmol/m2, respectively. Separation of aliphatic (C6–C12), aromatic (benzene, toluene and m-xylene) and some polar organic compounds (chloroform, ethylene chloride, chlorobenzene, p-chlorotoluene and ethyl benzene) by gas chromatography using columns packed with the prepared adsorbents was studied. It was concluded that the retention of some compounds was increased on the column packed with an adsorbent of 1.35 μmol/m2 concentration relative to that measured on the column packed with the unmodified silica gel. On columns packed with adsorbents with a higher bonded phase concentration than 1.35 μmol/m2, the retention times of all the compounds studied chromatographically decreased with an increase in the bonded phase concentration.

No abstract

The adsorption of a modifier (methanol) from the mobile phase on to a column packing surface and its influence on the retention of aliphatic hydrocarbons (C6-C12) and of benzene and some of its derivatives has been examined. Prior to such adsorption, the methanol adsorption isotherm was measured chromatographically by frontal analysis methods. A reduced retention of the compounds examined was observed as the concentration of adsorbed methanol increased. In addition, it was established that increasing concentrations of adsorbed methanol on the column packing surface led to a decrease in the selectivity of the latter.