Abstract: A process for performing sample analyses wherein reagents are filled portionwise into closed containers that comprise cells and carry codes identifying the reagent contained therein. Cells required for different analyses are placed in a rack together with a sample container containing the sample. A code identifying the sample is applied to the rack. The codes on the cells and the code on the rack are read with the same reading unit.

Abstract: A process for the purpose of the thermostatic control of a sample fluid to be analyzed, as well as reagents and optionally the solvents necessary for performing analyses in an automatically functioning analyzer, wherein the sample container containing the sample fluid as well as the cells containing the reagents are placed in a rack made from good thermally conducting material. The rack is fixed in the analyzer at the individual processing stations between two side walls. At least one of the side walls is heated, so that the rack is thermostatically controlled and, consequently, so is the sample fluid and the reagents.

Abstract: In a process for measuring the potential difference between a flow of sample liquid delivered by pumping and a reference electrolyte in which the sample flow is brought into contact with a reference electrode, the reference electrode contains a capillary channel, which extends substantially at right angles to the sample flow. The reference electrolyte is pumped at right angles to the capillary channel over its open end and the pumping of the flow of sample liquid and the flow of reference electrolyte starts and finishes simultaneously.

Abstract: A plastic reaction vessel for holding a small quantity of liquid comprises a vessel body which has a body flange (4) surrounding an opening formed in the body, a cover, and a connecting strip (5) which is integral with the vessel body and the cover. Opposite to the connecting strip (5), the body flange (4) has a downwardly facing abutment surface (25), which is engageable by a hooklike extension (23), which is formed on the cover (6) and extends downwardly when the cover is closed. The connecting strip (5) comprises a hinge portion (12) between its opposite end portions. The cover comprise a cylindrical skirt, which is adapted to be inserted into the vessel body through the opening therein. A sealing lip (8) is provided on the outside of said skirt at that end thereof which is adapted to be inserted into the opening of the vessel body.

Abstract: A measuring system comprises ion-selective electrodes adjoining a measuring passage, which has an inlet and an outlet. The measuring passage has bends, which are adjoined by the sensing electrodes, which are flush with the boundary surface of that measuring passage. Said bends extend also before and behind each electrode. The sensing electrodes are provided at the outside surface of each bend so that they will be effectively rinsed and errors due to entrained impurities will be avoided. The measuring passage is suitably substantially circular but has entrance and exit portions offset from the circular line. The electrodes are provided on the outside particularly in a star-shaped array. The measuring system is provided with a shield consisting of a closed, electrically conducting covering, which preferably consists of a metallic cover. Contact and contact pressure springs are subjected to a uniform stress because the cover is mounted with play by means of a hinge so that self-alignment will be effected.

Abstract: A cell for mixing operations and for optical examinations of liquids has a measuring region which has a small cubic capacity and a relatively large height. In a horizontal cross-section that measuring region has curved transitional wall portions between parallel end wall portions for receiving incident radiation and side walls. In the measuring region, the side walls have inwardly curved portions, which protrude inwardly to such an extent that in a transverse sectional view a tangent to the apex of each inwardly curved portion intersects the parallel end wall portions at an edge thereof or at a point which is inwardly spaced from said edge so that a double-tapered beam of measuring radiation will be closely approached by the inwardly curved side wall portion. At least one side wall portion may constitute a positive lens.

Abstract: In a process for mixing liquid samples to be analyzed, the liquid sample contained in a sample container is moved and mixed by a mechanically oscillated air column in contact with at least part of the liquid sample surface, the air column being excited with a frequency in the resonant range of the system formed by the air column and the sample liquid.

Abstract: A pipetting device serves to hold and actuate a detachably mounted syringe having a syringe body and a piston. The device is provided with means for adjusting the volumetric capacity of the syringe. The device comprises two racks and a pinion which is in mesh with both said racks and operable to move them in mutually opposite directions. The racks are connected to respective sliders, one of which is connected to a rod for actuating the piston of the syringe. A single actuating lever is provided for actuating the piston and is connected to the sliders by an actuating mechanism, which comprises a positively actuated transverse slider, which constitutes a stop member and in response to an automatic resetting of the actuating lever to its initial position is moved from the path of one of said sliders into the path of the other.

Abstract: A repeating pipetting device includes an elongated housing, a flange holder at one end of the housing for holding the flange of a syringe, a coupling assembly for connection to the plunger of the syringe, and a toothed rack connected to the coupling assembly and longitudinally reciprocable relative to the flange holder. A pawl is engageable with the teeth of the rack and is operable to advance the rack toward the flange holder in a succession of steps. An operating lever movable back and forth in the elongated direction of the housing, intermittently operates the pawl, and a return lever retracts the rack from the flange holder. A tongue-like cover or slide is provided within the device and covers the rack for a part of its length. The cover is slidably adjustable along the rack and has a portion engageable by the pawl which limits the extent to which the rack can be advanced by the pawl in each step.

Abstract: A mixing cuvette for mixing different substances introduced therein by high speed rotary mixing, the cuvette being of a relatively small capacity but defining a great filling height. The cuvette body is elongated and encloses an internal cavity defined in its upper portion by a peripheral side wall that merges into a polygonal multi-surface lower portion. This cavity is open at the top and closed at its bottom. The lower portion includes a measuring region with a pair of opposite planar parallel surfaces through which may be directed a photometric measuring beam.

Abstract: A detachable pipette tip member that may be "snapped" onto an adapter cone portion of a pipette body. The wall portion of the tip member engagable by the adapter cone defines a deformable conical sealing zone with yieldable characteristics obtained by a selective reduction of the wall thickness of the tip member in the sealing zone.

Abstract: A pipette device having an elongate casing with a handle portion at its upper end and an actuating button slidably mounted in the casing and projecting outwardly from the casing at the upper surface of the handle portion. The actuating button is coupled to a piston that is slidably movable within a cylinder disposed within the casing. The lower end of the casing mounts a conical adapter member for receiving replaceable pipette tip members. The actuating button is urged upwardly so that it projects from the upper end of the casing by spring means. A detent means within the casing allows to depress the actuating button into the casing against the spring means by a first distance corresponding to the displacement of the pipetting volume.

Abstract: Enzyme-kinetic determination of the concentration of an enzyme substrate which is acted on during an enzymatic reaction is carried out by adding at least one competitive inhibitor to an enzymatic reaction medium to bring the ratio of the substrate concentration C.sub.3 to the apparent Michaelis constant K'.sub.M to 0.2:1 or less, homogenizing the medium and determining the rate change of the enzymatic reaction at certain intervals of time.