Abstract: A multiport flexible diaphragm controlled valve is disclosed. The parts are all interconnected by low dead volume channels. The valve provides extremely fast response times, no moving parts other than the control diaphragm, operability over a wide range of operating conditions including high temperatures and is adaptable to use with all types of chromatography systems. The valve may also be utilized in a double sided configuration enabling two independent flow patterns to coexist simultaneously and be switched totally independent of one another.

Abstract: The separation of substances by membrane electrophoresis using the principle of isoelectric focussing is improved by the use of membranes of known isoelectric point and having buffering capacity. When such membranes are arranged in series of increasing isoelectric point from the anode (+) to the cathode (-) in a pH gradient of increasing pH in the same direction, and each membrane is located between electrolyte zones having pHs respectively lower and higher than its isoelectric point, the tendency for electro-endosmosis to occur during electrophoresis is substantially reduced.Methods for chemical treatment of agarose and other gel membranes to introduce acidic and basic groups so as to confer buffering power at the isoelectric point are described. These include the attachment of ampholytes to the gel by intermediate chemical linkages.

Abstract: A detector used in apparatus for measuring variations in the composition of a liquid includes a cell utilizing the Christiansen effect on light transmitted by the liquid flowing through the cell filled with particulate matter. The liquid and the particulate matter have indices of refraction that are substantially equal to one another at a specific wavelength. Variations of the transmitted light can determine changes of the refractive index of the liquid.Differences in the intensity of light transmitted through a sample cell and a reference device can be determined.