Abstract: A method includes passing a mobile phase fluid flow comprising liquefied CO2 through a separation column; then introducing a makeup fluid flow into the mobile phase fluid flow to form a mixed fluid flow; and then splitting the mixed fluid flow.

Abstract: A supercritical fluid chromatography system is provided with an injection valve subsystem for introducing a sample into a flow of mobile phase fluid. The injection valve subsystem includes an auxiliary valve and an inject valve. The operations of the auxiliary and inject valves are coordinated in such a manner as to reduce sample carry-over and system pressure perturbations occurring during sample injection.

Abstract: A supercritical fluid chromatography system is provided with an injection valve subsystem for introducing a sample into a flow of mobile phase fluid. The injection valve subsystem includes an auxiliary valve and an inject valve. The operations of the auxiliary and inject valves are coordinated in such a manner as to reduce sample carry-over and system pressure perturbations occurring during sample injection.

Abstract: A method includes passing a mobile phase fluid flow comprising liquefied CO2 through a separation column; then introducing a makeup fluid flow into the mobile phase fluid flow to form a mixed fluid flow; and then splitting the mixed fluid flow.

Abstract: Embodiments of the present invention feature heat exchange surfaces having a layer or coating having a lower surface tension than water, to repel water and prevent the formation of condensate on said surface.

Abstract: A non-reactive electrospray needle structure that can be used with relatively low electrical potential introduced externally at a selectable location along the length of the needle structure. The electrospray device or apparatus includes a non-conductive tube with an inner diameter, with one end of the tube having a reduced inner diameter thereby forming a tip. The tube is configured to have a fracture in it, positioned a predetermined or selectable distance from the tip. An electrically conductive path, such as a wire or electrode, is provided external to the tube and proximate to the fracture. A collar surrounds the tube proximate the fracture. The electrically conductive path provides a voltage potential to charge the spray. The collar maintains the conductive path in place, seals the tube at the fracture, and provides structural strength. In one embodiment, the tube is packed with a binding material to form a column bed.

Abstract: A system for forming a time modulated electrospray from a sample solution is provided. Further systems for analyzing this time modulated electrospray are provided. In a preferred such further system, a grid connected to a time modulated voltage source is provided between an electrospray apparatus and an analytical apparatus. More generally, a system for changing the energy of charged particles in a gas comprising the application of time modulated electric fields is provided.

Abstract: An electrically insulated needle tip is provided for forming an electrospray from a solution containing a solute sample. The insulated needle tip is positioned between an upstream electrode and a downstream counterelectrode. The solution passes through the needle, emerges from the insulated tip and is converted to an electrospray under the influence of an electric field generated between the electrode and the counterelectrode.

Abstract: Liquid chromatographic processing of compositions containing ionizable compounds. The chromatographic column is formed of a stationary packing having a chemical group chemically bonded thereto and a counter ion is added to the polar mobile liquid. The counter ion forms a reversible complex with at least one characterizing radical of at least one of the ionizable compounds.