Abstract:
The method according to the invention is a method of photometric in vitro determination of the content of oxygen in a blood sample. The 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 wherein a luminophor is provided, whereof the luminescence is quenched in the presence of oxygen. The oxygen content is 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 is also described.
Abstract:
The method is a method of photometric in vitro determination of a blood gas parameter in a blood sample. The blood sample is transferred directly from an in vivo locality to an at least partially transparent sample container, whereafter the connection between the sample containing sample container and the blood circulation is broken. Subsequently the sample container with its content of blood sample is brought into optical communication with an optical system comprising a radiation source and a radiation detector interacting therewith, preferably by placing the sample container in a sample container system in an analyzer. The blood gas parameter is determined on the basis of the radiation detected by the radiation detector. A system for photometric in vitro determination of a blood gas parameter in a blood sample is also described.
Abstract:
The concentration of molecular oxygen in a sample is determined by exciting oxygen molecules of the sample from the electronic ground state to the excited DELTA g state (excited singlet state), measuring a 1270-nm luminescence characteristic of the excited oxygen molecules (singlet oxygen) and correlating the luminescence characteristic measured with the concentration of molecular oxygen in the sample. Normally, the 1270-nm luminescence characteristic is the 1270-nm luminescence intensity. Preferably, the oxygen molecules are excited by being subjected to diffusion contact with a sensitizer such as a porphyrin or a porphyrin-related compound, e.g. a transition metal complex of a porphyrin. The sensitizer is brought into an oxygen-exciting electronic state by absorption of electromagnetic radiation such as light, the oxygen-exciting electronic state optionally being adapted to the measuring system employed by means of a quencher such as a substituted polyene. The sensitizer may be present in an organic solvent or a polymer such as polyvinylchloride. The oxygen-containing sample is preferably a sample of biological origin such as a blood sample.
Abstract:
The in vivo determination of an electrical potential difference across a human or animal membrane of a fluid-containing cavity, such as the stomach (200), is performed by arranging (e.g. via an endoscope (201)) a measuring half cell (20) (electrode and electrolyte) in its entirety within the cavity and in contact with the cavity fluid, and arranging a reference half cell (50) in contact with a human or animal fluid outside the cavity, typically the blood, suitably via a catheter (87). The concentration of a species such as a H concentration in gastric juice contributing significantly to a liquid junction potential between the measuring electrolyte and the cavity fluid is measured, preferably by means of a sensor such as a pH sensor (110), preferably arranged within the cavity, and a relevant correction of the potential difference measured is based on said concentration measurement.
Abstract:
An ion-sensitive measuring electrode device with an ion-sensitive element based on ion-conducting crystalline ceramic material. The electrode device shows a selectivity to the Na ion versus the H ion corresponding to the selectivity of the known sodium-sensitive glass-based solid membrane electrodes. Ion-sensitive measuring electrode devices showing good selectivity properties are provided on the basis of ion-conducting crystalline material, the crystal structure of which comprises a three-dimensionally extending interstitial space containing positions for the ion, especially material in which the interstitial space has bottlenecks which just permits passage of the ion. A method for preparing polycrystalline ceramic material based on oxides of zirconium, phosphor and silicon is also provided.
Abstract:
The present method is a method of photometric in vitro determination of the content of an analyte in a sample. The sample is located in a measuring chamber device with a measuring chamber, which has a defined radiation path length and has at least one at least partially transparent wall part. The measuring chamber is in optical communication with an optical system adapted for the analyte and comprising a radiation source and a radiation detector. Further, the measuring chamber is adjustable in shape thereby controlling the setting of the radiation path length across the measuring chamber. In a first measuring step a first radiation path length across the measuring chamber is set and radiation at at least one wavelength is transmitted from the radiation source through the measuring chamber and to the radiation detector. Then in a second step the measuring chamber is adjusted in shape thereby setting a second wavelength across the measuring chamber. Radiation at the same wavelength as during the first step is again transmitted from the radiation source through the measuring chamber and to the radiation detector. The analyte content is then determined on the basis of radiation detected in each of the measuring steps.
Abstract:
When performing the method a sensor (1) is used with a coil (15) integrated in a coil circuit. In the coil circuit a magnetic field is generated so that mutual induction can develop between the coil circuit and the surroundings of the sensor (1). The magnetic field in the coil circuit is detected intermittently, and a developed mutual induction is detected as a change of the magnetic field. The position of the sensor is monitored on the basis of said intermittent detection of the magnetic field in the coil circuit. The change of the magnetic field in the coil circuit can be detected in several ways. If the magnetic field is varying, the change may for example be detected as a change of the peak value of the voltage across or the current intensity through the coil circuit or be detected as a phase shift of one of these parameters. The method is used especially to ensure that calibration of the sensor (1) is performed only when the sensor (1) is located in a related calibration chamber (24). The detectable mutual induction is developed between the coil circuit with the coil (15) and an aluminum cup (22) constituting the calibration chamber (24).
Abstract:
A method for calibration of a potentiometric sensor comprising: selection of at least three calibration solutions all containing a well-known different concentration (C1, C2, C3, ...Cn) of the ion or the dissolved gas and at least one of the calibration solutions having a concentration which according to the response equation falls between the lower linearity limit point (P1) and the sensitivity limit point (P2), measurement of the potential (E1, E2, E3, ...En) of each of these solutions, insertion of these values of potential and concentration into the theoretical response equation for the sensor Ei = E'0 + S . log (Ci + C0), determination of the values of the unknowns E'0, S and C0, and determination of the response equation for the sensor by inserting the unknown values into the theoretical equation.
Abstract:
The glass electrode comprises a membrane of ion sensitive glass. The membrane comprises a composite material consisting of a matrix of ion sensitive glass and a dispersed filling material therein having higher tensile strength than the matrix. The membrane of the glass electrode is particularly resistant to mechanical stress and the glass electrode is i.a. applicable in a tc Pco2 electrode of the Severinghaus-type.
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). 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 the sensor in question with its measuring surface in front is inserted through the second chamber (10) into the housing (2) until abutment against a shoulder (6) in said 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 same into the housing (2). The disclosed device - which is particularly suited for use in calibrating sensors for transcutaneous registering of the contents of CO2 and/or O2 in blood - is self-contained, and can be made of a very compact design, making it very well suited for use in connection with portable equipment. Further the device is suitable for being manufactured in the form of a disposable unit.