Abstract: An assay cartridge suitable for use with automated analytical instruments which include a conveyor such as a carousel. The cartridge is configured with ledges extending outwardly from sides thereof, preferably at the bottom of the cartridge. The conveyor includes berths for receiving the cartridges, each berth being formed as a depressed region within a top surface of the conveyor and bounded by a floor at the bottom of the berth and opposed sidewalls and an end wall extending upwardly from the floor. The sidewalls are preferably parallel to each other. An open end of the berth, opposite the end wall serves as a port through which the cartridge is inserted and extracted from the berth. Each of the sidewalls of the berth is provided with a shoulder which extends inwardly towards a center line of the berth, and upon insertion of the cartridge, extends over the ledges of the cartridge to serve as a guide. The guide includes grooves formed between the shoulders and the floor.

Abstract: There is described a fluid dispensing system which includes a pipette assembly adapted for use with disposable pipette tips. To ensure a precise location of a disposable pipette tip on the distal end of the stem of the pipette assembly which holds the pipette tip, a proximal chamber of the pipette tip envelops the distal end of the stem and includes a ledge which encircles an annular region of the stem to form an abutment for the stem and establish a precise distance between the distal end of the stem and the pipette tip orifice. In a preferred embodiment the fluid dispensing system is incorporated in an automated analytical instrument.

Abstract: An assay cartridge suitable for use with automated analytical instruments which include a conveyor such as a carousel. The cartridge is configured with ledges extending cutwardly from sides thereof, preferably at the bottom of the cartridge. The conveyor incudes berths for receiving the cartridges, each berth being formed as a depressed region within a top surface of the conveyor and bounded by a floor at the bottom of the berth and opposed sidewalls and an end wall extending upwardly from the floor. The sidewalls are preferably parallel to each other. An open end of the berth, opposite the end wall serves as a port through which the cartridge is inserted and extracted from the berth. Each of the sidewalls of the berth is provided with a shoulder which extends inwardly towards a center line of the berth, and upon insertion of the cartridge, extends over the ledges of the cartridge to serve as a guide. The guide includes grooves formed between the shoulders and the floor.

Abstract: There is described an analytical isntrument for the analysis of fluids such as biological fluids. The instrument includes a fluid dispensing system having a pipette for dispensing fluid test samples and test reagents to assay cartridges. An optical detection system provides a light beam which intercepts a downward travel path of the pipette prior to its reaching the dispense position. Measurement of the intensity of the light beam in conjunction with the position of the pipette enables a controller to indicate the presence or absence of a pipette tip. In addition, interception of the light beam by the pipette initiates a final approach sequence for the pipette to the dispense position above an assay cartridge by a predetermined increment of travel.

Abstract: A method of calibrating pipette position in an automated assay instrument employing a conveyor for holding assay cartridges and a transport for transporting a pipette between various locations is accomplished by alignment of a pipette stem with targets located at various locations within the system. Two targets are located on a tray having a plurality of reservoirs for holding liquid, and one target is located on a dummy cartridge carried by the conveyor. An indicator having a spring-loaded tab is used in conjunction with a pipette stem modified by inclusion of a circumferential slot for receiving the spring loaded tab. The stem is inserted into the indicator and locked therein, with limited sliding being provided by movement of the tab within confines of the slot. Alignment marks are provided on both the stem and the indicator to permit visual alignment of the stem relative to a target upon abutment of the indicator with the target.

Abstract: A liquid transport system provides controlled flow of liquid in a liquid flow zone between two surfaces wherein one surface includes a plurality of projections, or raised areas, arranged substantially throughout the surface in the liquid flow zone and an aperture for allowing the introduction of liquid between the two surfaces. In a preferred embodiment the projections on the first surface are arranged in parallel spaced rows and parallel spaced columns. The second surface may be one surface of a layer of a diagnostic assay element.