A process for determining the degree of saturation of a solution comprising a solvent and a compound of limited solubility which involves the steps of (1) diluting a feed solution of the compound of limited solubility, (2) passing a sample of the diluted feed solution through a bed of a solid solution of the compound and a tracer in which the tracer is intrinsically incorporated into the crystal structure of the compound, so that the diluted feed solution being tested becomes saturated with the compound by dissolution of a portion of the solid solution in the bed, (3) measuring the concentration of the tracer in the sample after passage through the bed of solid solution, thus measuring the amount of the compound dissolved from the solid solution to saturate the diluted feed solution, and (4) determining the degree of saturation of the compound in the feed solution from the measured values

A reactor/separator device is provided for use in automated solid phase immunoassay. The device is a column, fitted at the bottom portion thereof with a water impermeable disc which can hold immunoabsorbents immobilized antisera, ion exchange resins and the like. When the contents of the column supported by the disc are brought into contact with an aqueous phase containing reagents or reactants by centrifugal force, a chemical reaction is initiated. After reaction, centrifugally applied pressure forces the aqueous phase through the filter disc making it water permeable and separating a desired component for subsequent analysis.

A method and apparatus for conducting chemical reactions at a liquid-solid interface wherein a reaction component is fixed on the surface of a solid phase immersed in a liquid phase containing a freely diffusing, mobile reaction component. The apparatus comprises a substantially smooth-surfaced matrix of appropriate geometrical configuration designed to provide a large surface to volume ratio, a short transfer distance from the mobile component to the fixed component distributed on the solid phase surface and to drain freely upon removal from the reaction liquid.

A centrifuge tube for collecting and dispensing a mixed concentrated fluid sample. The centrifuge tube has an elongated tube body with an open top end and a bottom end preferably having a dispensing spout. A divider insert is positioned inside the inner volume of the tube body to divide the inner volume into upper and lower chambers. The divider insert has a funnel shape with an inverted conical section and a funnel spout having a spout tip. The spout tip extends into the lower chamber while remaining above the bottom end. Upon filling the upper chamber with a fluid and subjecting it to centrifugal forces inside a centrifuge, a concentrated fluid sample is collected in the lower chamber with an air pocket captured between the spout tip and the divider insert. The concentrated fluid sample may then be agitated to mix the sedimented solids with the liquid of the concentrated fluid sample, and the now mixed concentrated fluid sample subsequently dispensed through the dispensing spout.

A method of measuring the degree of partitioning of a labeled species between free and bound states which involves the use of an insoluble porous monolith having a means for binding a portion of the labeled species within the pores thereof, which monolith is capable of substantially attenuating the signal emitted by labeled species subsequently bound within the pores thereof.