EVALUATION OF MICROBORE AND PACKED CAPILLARY COLUMN CHROMATOGRAPHY WITH AN ETHYLVINYLBENZENE DIVINYLBENZENE POLYMERIC PACKING MATERIAL AND SUPERCRITICAL AMMONIA AS THE MOBILE PHASE

An investigation into the use of ammonia as a mobile phase for high-re solution supercritical fluid chromatography was conducted. A highly cr oss-linked ethylvinylbenzene-divinylbenzene polymeric packing material (5-mum diameter) in microbore stainless-steel and nickel capillary tu bing demonstrated reasonable efficiencies (ca. 10 000-15 000 plates m- 1, after initial exposure to ammonia) without phase degradation as pre viously observed when using open-tubular capillary columns. However, a mmonia treatment caused an initial rapid loss in efficiency (ca. 42%) for reasons as yet undetermined. The polymeric packing materials were much more inert than conventional silica-based packing materials. Sepa rations of polar drugs, underivatized amino acids and defoliant herbic ides are shown.