Abstract:
The present method is a method of electrochemical stripping analysis comprising an electrolysis step and a stripping step. In the method is used an electrode device comprising an electrode body carrying a working electrode, a reference electrode, and a counter electrode. The electrode device comprises a measuring area located at an outer surface of the device, into which area the working electrode opens and wherein at least one contact point for the reference electrode and the counter electrode is located. The electrode device is adapted for dipping into a sample solution contained in a sample container. The measuring area of the electrode device has a surface character appropriate for retaining an aqueous sample residue at said surface after removal of the electrode device from the sample solution. Said residue is of sufficient size to maintain electric contact between the working electrode and the contact point for the reference electrode and the counter electrode and is preferably of sufficient size to completely cover the working electrode. Thus, during displacement from one solution to another, the working electrode is protected from damage caused by an uncontrolled electrode potential, from drying out, and from formation of contaminations. By means of the present method it is possible to perform the electrolysis step of the analysis in the sample and perform the stripping step in another more appropriate solution.
Abstract:
The biosensor comprises a working electrode, a reference electrode, and a membrane comprising a substrate-limiting layer and an enzyme layer. At the substrate-limiting layer is provided a protection layer having hydrophilic properties corresponding to the properties of regenerated cellulose or being more hydrophilic than regenerated cellulose. Particularly, the substrate-limiting layer is constituted by a polyurethane layer and the protection layer is constituted by a cellophane layer.
Abstract:
New apparatus for measuring parameters such as pH, pCO2, pO2, and Hb content of physiological fluids, especially blood, is described. The apparatus comprises novel means for suspending reagent vessels (34, 35, 40, 45, 50) having shoulders (51, 52) and containing calibrating solutions, rinsing solutions etc., as well as for suspending a liquid waste vessel (26) by suspending the vessels between rods (53, 54) fed to the analyser. The reagent vessels are provided with caps (55, 58) at the top and include liquid reagent conduit extending from the outlet aperture of the cap down into the liquid. When the vessel is mounted on the anaylser a fixed inlet tube extending horizontally outwardly from the analyser penetrates a seal across the outlet aperture and connects with the liquid reagent conduit.
Abstract:
A method and an apparatus for chemical analysis of samples of varying matrices is disclosed. The samples are transported in series by a carrier fluid. At a test location is provided a fluid elemement the chemical composition of which is maintained essentially constant in consequence of the exposure of the fluid element to the carrier fluid prior to and subsequent to the exposure of the fluid element to each individual sample.
Abstract:
A method for determining the level of an analyte in a sample of whole blood uses the technique of internal reflection spectroscopy and an apparatus suitable for the technique. The method is of particular use to detect the attenuation of the totally reflected light by absorption of the evanescent wave, e.g., by haemoglobins. In the apparatus (1) incident light is directed via a light guide (7) to the reflection element (3) and the attenuated totally reflected light is directed out of the element to a photodetector (12) by a light guide (11). In the whole blood in the cuvette (18) the cells are removed from the interface (8) by gravity to leave blood cell free plasma (4) adjacent the interface (8). Thus analytes present in the plasma can be detected. The extent of haemolysis can be estimated.
Abstract:
Sensor (1) for determining the concentration of a biochemical species. The sensor (1) works according to a competitive principle and the response-giving active part (2) of the sensor comprises the two partners in an affinity pair immobilized on two parts of substrate. One of these partners consists of the biochemical species or a competitor hereto.
Abstract:
An electrode assembly for transcutaneously measuring a blood gas parameter and for measuring a bioelectrical signal comprises two separate electrode devices (10, 40), one of which (10) further comprises an electrochemical measuring electrode system. The electrochemical measuring electrode system comprises a reference electrode of a potentiometric electrode system and an anode of a polarographic electrode system constituted by a single metallic body (13), a pH-electrode (31, 32) of the potentiometric electrode system, and a noble metal cathode (33, 34) of the polarographic electrode system. The bioelectrical signal sensing electrode of the electrode device (10) is further constituted by the metallic body (13). A first part of the metallic body (13) is covered by an electrolyte solution (28) which communicates electrolytically therewith and further the pH-glass electrode and the noble metal cathode, and a second part of which is not covered by the electrolyte solution but adapted to electrically conductively communicate with a skin surface part of a test person or a patient through an electrically conductive contact liquid (19). The membrane separates the first and the second part of the metallic body from one another. The second electrode (40) comprises a bioelectrical signal sensing electrode (41), which is adapted to electrically conductively communicate with a skin surface part of a test person or patient through an electrically conductive contact liquid (20). By means of the electrode assembly coincident measuring results of the blood gas partial pressures of oxygen and carbon dioxide and of a bioelectrical signal such as the ECG (electrocardiography), the RR (Respiration rate) or the heart rate of the test person or patient is obtainable.
Abstract:
An ion selective electrode device, in particular a pH-sensitive electrode device, employing an intercalation electrode (3) as contact material between an ion selective element (2) and an electrical connection (9). An intercalation electrode comprising an equilibrium mixture of two phases, at least one of the phases working as an intercalation electrode, is disclosed. The electrode device may be constructed as a solid state electrode device showing advantageous electrode properties.
Abstract:
Selon les principes de mesure transcutanée d'un paramètre du sang, tel que la pression partielle d'un gaz sanguin, un dispositif à électrode de mesure électrochimique (1) est appliqué sur la surface (2) de la peau d'une personne. Le dispositif à électrode comprend un corps (10), p.ex. un substrat à film épais, thermo-régulé à une température prédéterminée à l'aide d'un thermostat et, de plus, il comprend un moyen détecteur (11) associé à une membrane (14) retenant une solution d'un électrolyte dans un réservoir d'électrolyte (15). De plus, le dispositif à électrode possède une chemise comprenant un corps métallique annulaire (16), un corps métallique (4) et un substrat à film épais (8) qui est thermo-régulé à l'aide d'un thermostat à la même température que celle du corps (10) du dispositif à électrode. Lorsque le corps est amené en contact de la surface de la peau, une partie de la surface annulaire de la chemise est également amenée en contact de la surface de la peau de sorte qu'une chemise de chauffage virtuelle est établie dans la peau sous la partie de surface annulaire de manière à diriger sensiblement tout le flux de chaleur depuis le corps vers les tissus se trouvant directement sous la surface de la peau. En mesurant l'énergie électrique fournie pour thermo-réguler le corps à la température prédéterminée à l'aide du thermostat, l'écoulement de sang capillaire local dans les tissus (2) sous la peau est mesuré, et le paramètre du sang en question est mesuré à l'aide des moyens détecteurs (11). Dans un mode alternatif de fonctionnement, le dispositif à électrode est adapté pour mesurer des températures du corps en profondeur en thermo-régulant la chemise à l'aide d'un thermostat à une température telle que la température enregistrée par un détecteur de température du corps et la température enregistrée par un détecteur de température de la chemise soient identiques et, par conséquent, soient identiques à la température en profondeur du corps.
Abstract:
The sensor (1) comprises a sensor body (3) thermostatable by means of a first thermostating system (14, 15) and having an outer surface (3a, 40a) for application to the human body (28) in heat conductive relationship therewith, said outer surface (3a, 40a) forming the measuring surface of the sensor (1). The sensor (1) further comprises analyte sensing means (7, 8) arranged in said sensor body (3) and being thermostated through said body (3) by means of the first thermostating system (14, 15). The sensor (1) further comprises means (16, 41) arranged in the sensor body (3) in heat insulated relationship therewith while in heat conductive relationship with a delimited surface part of the sensor measuring surface (3a, 40a). The means (16, 41) is thermostatable by means of a second thermostating system. The delimited surface part is located within the outer periphery of the sensor measuring surface (3a, 40a). When using the sensor (1) the heat flux (34) from the measuring surface surrounding said delimited surface part provides a heat shield in the tissue, said heat shield surrounding the heat flux (35) from the delimited surface part. Thus, the heat flux (35) from the delimited surface part will be guided substantially unidirectionally to the tissue (28) located directly beneath the delimited surface part and absorbed therein.