Abstract:
In a method of photometric in vitro determination of the content of oxygen in a blood sample, a blood sample is transferred directly from an in vivo locality to an at least partially transparent sample container of a sampling device. The sample container has a measuring chamber containing a luminophor, the luminescence of which is quenched in the presence of oxygen. The luminophor is excited by irradiation with radiation from a radiation source. The luminescence emitted by the excited luminophor is detected by a radiation detector and the oxygen content determined on the basis of the radiation detected by the radiation detector. A sampling device and a system for photometric in vitro determination of oxygen in a blood sample are also described.
Abstract:
In one embodiment the calibration device (1) comprises a housing (2) which by means of a removable lid (8) and a rupturable barrier layer (3) is divided into a calibration chamber (4) and a second chamber (10). The calibration chamber (4) contains a calibration fluid (5)--e.g. a dry gas--while second chamber (10) contains a second fluid (11)--e.g. a wetting agent. Immediately prior to a calibration process the lid (8) is removed, whereafter a sensor with its measuring surface in front is inserted through the second chamber (10) into the housing (2) until it abuts against a shoulder (6) in the housing (2). This causes the barrier layer (3) to rupture and the second fluid (11) to contact the calibration fluid (5). Hereafter the calibration process can take place. In another embodiment the device (1) further comprises a membrane (12) which is accommodated in the second chamber (10) and is adapted to be secured to the sensor during the insertion of the sensor into the housing (2). The disclosed device--which is particularly suited for use in calibrating sensors for transcutaneous registering of the contents of CO.sub.2 and/or O.sub.2 in blood--is self-contained, and can be made in a very compact design, making it very well suited for use in connection with portable equipment. The device is also suitable for being manufactured in the form of a disposable unit.
Abstract:
A measuring device, intended for measurements on whole blood, comprises a sample fluid chamber for containing a blood sample, ion-selective potentiometric electrodes for measurement of the concentrations of sodium and potassium ions, a reference potentiometric electrode, an optical sensor for measuring the concentration of glucose by means of a color reaction, a cuvette having a window permitting spectrophotometric measurement of the level of haemoglobin, a conditioning (calibration) fluid chamber in which the ion-selective electrodes and the reference electrode are exposed to a conditioning (calibration) fluid comprising known concentrations of sodium and potassium ions (thereby facilitating calibration of the response of the ion-selective electrodes), a rupturable pack containing the conditioning fluid and from which the fluid is released into the conditioning fluid chamber upon application of pressure to the pack, and a wall part which partly defines the sample fluid chamber and has weakened areas which are ruptured upon movement of the sensors (i.e. the electrodes and the glucose sensor) so as bring the sensors into contact with the blood sample and which establishes a seal around the sensors.
Abstract:
An electrode device for the determination of the partial pressure of CO.sub.2, Pco.sub.2, in particular an electrode device for transcutaneous determination of Pco.sub.2.The interior electrolyte of the electrode device is adapted to the exterior electrolyte in such a manner that the potential difference measured over the exterior reference electrode and the interior reference electrode is substantially temperature-independent with a temperature dependence for the CO.sub.2 partial pressure determination in the range of -1%/.degree.C.-+1%.degree.C.The interior electrolyte preferably contains a pH-buffer system based on phenyl phosphonic acid.
Abstract:
Subtilisin or subtilisin-like enzymes are used in rinse solutions for apparatus analyzing protein-containing biological liquids, such as blood analysis apparatus, to obviate measuring errors ascribable to protein deposits. A preferred rinse solution contains subtilisin, a borate buffer, and germicides.
Abstract:
An electrochemical electrode device for simultaneously measuring the partial pressures of two gasses in a medium of limited gas availability one of which is measured potentiometrically and another one of which is measured polarographically comprises an electrode body (18) constituting a reference electrode relative to a pH-electrode (19) of a potentiometric electrode system, and a anode relative to a cathode (20) of a polarographic electrode system. Furthermore, the electrode device comprises an electrolyte solution (28) enclosed between the electrode body and a membrane (30). The membrane comprises a basic membrane layer (31), preferably of polytetrafluoroethylene (PTFE) or fluoroethylenepropylene (FEP) of a thickness of about 12 .mu.m, and a covering (32), preferably a polypropylene layer of a thickness of about 15 .mu.m, which covers part of the basic membrane layer so that an uncovered area (34) is constituted in front of the pH-electrode. The uncovered area constitutes a first membrane part showing high permeability to the first gas and constitutes together with the potentiometric electrode system and the electrolyte solution a first measuring system for measuring the partial pressure of the first gas. A covered area of the basic membrane layer constitutes together with its covering a second membrane part showing low permeability to the second gas and is arranged in front of the exposed measuring surface of the cathode so as to restrict the diffusion of the second gas to the cathode and together with the polarographic electrode system and the electrolyte solution to constitute a second measuring system for measuring the partial pressure of the second gas.
Abstract:
A syringe for collecting a sample of blood or another liquid comprises a syringe cylinder and a piston arranged displaceably therein. One or more axially extending recesses are formed in the inner wall of the syringe cylinder axially spaced from the inner end thereof. The recess or recesses contain a material which is pervious to gas and impervious to liquid, such as a hydrophobic material, a hydrophilic material with capillary effect, or a material which swells when contacted by liquid. The sample collecting chamber within the cylinder may be vented to the atmosphere by placing the piston in the recessed area of the cylinder. Arterial blood may then pass into the syringe under arterial blood pressure, and the flow of blood into the syringe is automatically stopped when the sample collecting chamber of the syringe has been filled, because blood cannot pass the liquid impervious material arranged in the recesses. The axial innermost portion of the inner cylinder wall, which is not recessed, may cooperate with the piston in a conventional manner so as to provide a suction effect within the blood collecting chamber, if desired.
Abstract:
The invention relates to a method of removing air or gas bubbles tending to collect in the "dead space" of a piston burette or another liquid dosage piston pump during operation thereof. The venting is performed by sucking a substantial volume of air into the pump cylinder in addition to a certain amount of liquid, and the air and part of the liquid within the pump cylinder is thereafter discharged therefrom. A piston dosage pump for carrying out this method comprises a valve mechanism by means of which the pump cylinder may be selectively communicated not only with a liquid inlet conduit and a liquid outlet conduit, but also with an air inlet passage.
Abstract:
A block-shaped measuring chamber unit, especially for use in electrochemical measuring apparatuses for defining measuring chambers therein. The block-shaped unit has oppositely directed or otherwise differently orientated surface parts each defining a depression to be used as a measuring chamber. These depressions are interconnected by means of straight bores or passages extending through the block-shaped unit. The block-shaped unit is preferably made from machinable glass-ceramic.
Abstract:
A sampling device for photometric determination of the content of an analyte in a sample of whole blood has at least one measuring chamber having locally transparent wall parts, at least one wall part being sufficiently deformable to facilitate displacement of the whole blood sample from the measuring chamber, with a transparent body having a radiation transmission characteristic dependent upon the concentration of a predetermined analyte in the whole blood sample disposed between the wall parts. The sampling device is employed in an analyzer for photometric determination of the content of analyte in a sample of whole blood and in a method of photometric in vitro determination of the content of an analyte in a sample of whole blood. In the method, a sample of whole blood is transferred directly from an in vivo locality to the sampling device, the measuring chamber therein is deformed in a controlled manner to substantially drain the whole blood from the measuring chamber, radiation is transmitted through the substantially drained measuring chamber, detected, and the analyte content determined. A measuring chamber for photometric determination of an analyte in a sample of whole blood has locally transparent wall parts, at least one being sufficiently deformable to facilitate displacement of the whole blood sample from the measuring chamber, and a transparent body disposed between the wall parts. The measuring chamber is employed in an analyzer and in a method for the photometric determination of an analyte in a sample of whole blood.