Chemically bonded chelates as selective complexing sorbents for gas chromatography .6. Modification of silica with NiCl2 and CoCl2 via beta-diketonate groups

Results are presented of studies of new types of packings for gas chromatography which contain nickel(II) and cobalt(II) chlorides and nickel(II) acetylacetonate chemically bonded via beta-diketonate groups to a silica surface. Taking into account the ability of the metals in the chlorides and acetylacetonate to interact with compounds showing electron-donor properties, the study was performed using such adsorbates as aliphatic linear and branched hydrocarbons. The study allowed the determination of the influence of structure and configuration of adsorbate molecules on their retention and the definition of the usefulness of thus prepared packings in chromatographic analysis. The obtained results point to selectivity of the packings to the compounds which contain pi electrons. Moreover, to determine the influence of the type of functional group bonded with hydrocarbon chain of a given silane on charge-transfer interactions, the obtained results were compared with those for the packings in which nickel(II), cobalt(II) chlorides and nickel(II) acetylacetonate were bonded with silica via diphenylphosphine groups.