Abstract: A solid phase extraction device has a solvent-compatible permeable membrane with a bubble point greater than the normal operating pressure differential used and a sorbent material retained by two disks or frits so that when pressure is applied, the sample to be processed will pass through the membrane, but the membrane will not permit air to pass therethrough, and the sorbent remains wet throughout the process. The device has an input port and an output port and operates to maintain a pressure differential between the ports. Sorbent material is entrapped between two disks or frits. Located above the sorbent material is a support having a grid surface. The support prevents the frit from "riding up" the column of the barrel. Ultrasonically welded to the support is a solvent-compatible permeable membrane. The membrane is hermetically sealed to the support and the support is self-locked to the interior barrel of the device.

Abstract: A thin layer chromatography plate is disclosed for two-dimensional chromatography of a sample, in which the plate has a first surface portion including a first composition suitable to perform thin layer partition chromatography in a first direction on the plate and a second surface portion including a second composition suitable to perform thin layer chromatography in a second direction on the plate, wherein the second composition is selected from the group consisting of (1) a composition, different from the first composition, suitable to perform thin layer partition chromatography and (2) a composition suitable to perform adsorptive thin layer partition chromatography. A method of using such a plate is also disclosed.

Abstract: Methods for packing chromatographic columns are disclosed, including introducing a packing material into a chromatographic column under the influence of a first pressure differential until the column is filled to a desired extent with the packing material, and subsequently establishing a substantially regular periodic vibration along the length of the column and subjecting the packing material to a second pressure differential, which is preferably greater than the first pressure differential. The substantially regular periodic vibration can comprise ultrasonic vibration, which is preferably applied to the column by immersing it in a liquid bath and subjecting the liquid bath to ultrasonic vibrations.