Preparation of a sulfoxide group and ammonium-salt bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils.

In this study, a silica stationary phase modified with sulfoxide group and ammonium-salt was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic sulfide was attached to a diamino (primary and secondary amino) bonded silica surface by an amide bond, and the bonded sulfide groups were oxidized with periodate to afford sulfoxide groups bonded to the stationary phase. The secondary amino groups in the spacer chain were converted to ammonium-salt by the addition of hydrochloric acid.