Abstract: A fluid control device for use in a fluid chromatography system comprising a control plate with a radial channel structure and a porous plug to create a fluid distribution across the entire cross sectional area of a separating matrix yielding increased efficiency in fluid chromatography operations.

Abstract: Liquid chromatography apparatus including a hollow cylinder and a fixed end closure in which the effective useful length of the cylinder is varied through the use of a piston member that slides within the cylinder due to force exerted by a threaded shaft that is connected to a handle. Binding of the piston member in the cylinder is prevented by a ball joint that operatively connects the piston member to the threaded shaft and by a plurality of O-rings located on the piston member that contact the inner wall of the cylinder and tend to prevent tipping of the piston member. Even liquid distribution and filtering is obtained through a 0.5 micron porous sintered stainless steel liquid distribution disk. A smooth inclined surface in combination with an uninterrupted ring provide a trap for bubbles of gas located inside the cylinder.

Abstract: Apparatus and method are disclosed for detecting the presence of a analyte in a sample. The apparatus includes an optical transmitter and receiver for transmitting light toward the sample and receiving a portion of the reflected light. The optical receiver acts in conjunction with a data processor to convert the reflected light to data representing the density of analyte in the sample. The apparatus thus disclosed is portable and can be transported to remote testing sites.