Abstract: Particulate chromatography medium such as silica is packed into a chromatography column (2) along a feed conduit (16, 18) leading to a packing port (1) through the column wall. A motive flow of a liquid packing vehicle such as a non-polar organic solvent is established along a feed conduit by a pump (111). The medium, for example silica which is poorly compatible with low-polarity vehicles, is easily entrained in the motive flow by introducing it into the feed conduit (16, 18) via an ejector (30). This avoids subjecting the medium to the action of a mechanical pump.

Abstract: Particulate chromatography medium such as silica is packed into a chromatography column (2) along a feed conduit (16,18) leading to a packing port (1) through the column wall. A motive flow of a liquid packing vehicle such as a non-polar organic solvent is established along a feed conduit by a pump (111). The medium, for example silica which is poorly compatible with low-polarity vehicles, is easily entrained in the motive flow by introducing it into the feed conduit (16,18) via an ejector (30). This avoids subjecting the medium to the action of a mechanical pump.

Abstract: A method for treating silica to render its surface non-polar, especially for use as a chromatography medium in "reverse phase" chromatography. The silica is treated with a solution of a complex in which a hydrocarbon chain is coordinated, e.g. through a carboxylic group, with a metal ion such as chromium. The complex also has halide ligands, which on hydrolysis give rise to cationic charging and hydroxyl-bridging of the complex molecules with the silica surface and with one another. Elimination of water binds the molecules onto the silica surface where their hydrocarbon chains give the desired non-polar properties.