Patent ID: 6415670
Filing Date: 2002-07-09
Classification: B01D,G01N

Abstract:
An injection apparatus for preparative liquid chromatography comprising: a first switching valve one or more kinds of solvents to be supplied thereto, selectively connected to any of a plurality of injectors at one end thereof; each injector comprising a cylinder having a ring-shaped recess in the inside wall, two end plugs supported by the cylinder, and a floating plug movably inserted in the cylinder and positioned between the two end plugs, the floating plug isolating a sample liquid from the solvents in the cylinder before the floating plug reaches the recess; a second switching valve which is selectively connected to any of the plurality of injectors at the other end thereof; a third switching valve which is connected to the second switching valve and is selectively connected to any of a plurality of columns at one end thereof; and a fourth switching valve which is selectively connected to any of the plurality of columns at the other end thereof, a conduit connected between one port of the first switching valve and one port of the second switching valve; at least one liquid sensor is provided between the second switching valve and the third switching valve; wherein the valves are driven so that a selected column is connected to a selected injector only when liquid is continuously detected by all of the liquid sensor and the solvents are supplied to the selected column through the conduit after the sample liquid is sufficiently discharged from the selected injector.