Abstract: The present invention is directed to a fluorescence polarization assay for opiate alkaloids and their metabolites, to the various components needed for preparing and carrying out such an assay and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for making them. The tracers and the immunogens are made from substituted opiate alkaloids. A fluorescein moiety is included in the tracers, while a poly(amino acid) forms a part of the immunogens. The assay is conducted by measuring the degree of polarization retention of the fluorescence resulting when a sample mixed with antiserum and tracer is irradiated with plane-polarized light.

Abstract: A drop detecting system has light emitting diodes and phototransistors located on either side of a translucent drip chamber. The phototransistors respond to either the shadow or the reflection from a drop falling through a light beam produced by the light emitting diodes. The electrical response from the phototransistors is conducted to an integrator circuit which generates an electrical signal voltage. A comparator circuit receives the electrical signal voltage from the integrator circuit and outputs a signal indicating the presence of a drop passing through the drip chamber. A drip chamber housing cooperates with the drip chamber to shroud the translucent portion of the drip chamber. Additionally the drip chamber housing provides for the mounting of the light emitting diodes and the phototransistors.

Abstract: A pressure plate for a peristaltic pump utilizing flexible tubing has an arcuate surface and a pivot mount. The arcuate surface is retained in operative association with the flexible tubing by a spring bias.

Abstract: This disclosure relates to a method and reagents for determining ligands in biological fluids such as serum, plasma, spinal fluid, amnionic fluid and urine. This disclosure also relates to a novel class of tracer compounds employed as reagents in fluorescence polarization immunoassays.

Abstract: A magazine is disclosed for dispensing generally cylindrical and elongated articles in a pre-determined order. The magazine comprises a series of shelves with a reciprocating ratcheting plate arranged perpendicular to the shelves. The ratching plate has surface configurations which allow the articles to be advanced in one direction of movement, and remain stationary relative to the shelves in a second opposite direction. The magazine is removable and may be pre-loaded to dispense in a pre-determined order. The magazine finds particular application in the dispensing of samples to an automated analyzer.