Abstract: In order to produce a sensitive membrane electrode with high selectivity with respect to other anions and lipophilic ions or interfering substances, the membrane is based on an unplasticized polymer matrix whose content of electroactive component is between 50 and 90 percent by weight.

Abstract: In an O.sub.2 sensor element which contains a fluorescent indicator substance, a polymerized silicone polymer is used as a carrier material in which the indicator substance is incorporated in solubilized form and in an at least approximately homogeneous distribution. Solubilization of the indicator substance may essentially be performed in analogy to Friedel-Crafts alkylation of aromatics, which will increase solubility of the indicator substance in the polymer carrier without affecting quenching behavior.

Abstract: In an optical sensor used mainly for determining the partial pressure of O.sub.2 or CO.sub.2 in respiratory gas includes a sample measuring chamber through which sample medium to be analyzed flows or into which it is fed, a reference measuring chamber containing a reference gas or a reference liquid of constant composition, a light source, a unitary excitation filter positioned between the light source and first sides of both the sample measuring chamber and the reference measuring chamber, a single fluorescent sensor element on the second sides of both the sample measuring chamber and the reference measuring chamber, and first and second detectors for detecting the fluorescence radiation from the fluorescent sensor element respectively based on the light passing thereto from the sample measuring chamber and the reference measuring chamber.

Abstract: In a sensor element for determining the O.sub.2 content of a sample, comprising a fluorescent indicator substance which is embedded in a polymer carrier and with which the sample may be brought into contact, a fluorescence extinction sufficiently high for yielding useful measurement results is achieved by the use of plasticizer-compatible polymers as carrier materials which contain plasticizers in addition to the indicator molecules.

Abstract: Between a substance to be analyzed and a sensor there is placed at least one membrane, forming part of a sample vessel containing a sample to be analyzed and being permeable for a species depending on the substance to be analyzed. This membrane constitutes at least one wall of the sample vessel, through which the active sensor surface may be brought into contact with the substance to be analyzed. The sensor is designed as a separate unit which is movable relative to the sample vessel, with which its membrane may be brought into contact. For the purpose of measurement the sensor is contacted by the membrane stretching over the active sensor surface which in itself does not carry a membrane.In this way the sensor cannot be contaminated by the sample, and the device may be successfully used for series measurements.

Abstract: An analyzing apparatus for the analysis of liquid samples is provided with a single sample input unit and a serial sample input unit which may alternatively be connected to a joint evaluation unit by means of a change-over switch. This will permit the measurement of single samples during a serial sample run by interrupting the automated process, additional provisions ensuring an automatic return to the serial sample mode.

Abstract: An electrochemical measuring apparatus may be charged with an option of several media by providing a feeder part with the respective media connections, and by guiding a piece of pipe in a bore, which is sealed off and is movable relative to this feeder part. On its end facing away from a measuring chamber in the apparatus, the piece of pipe has a connection for additional media. Besides, it carries at least one circumferential bore which may be brought to coincide with at least one of the input openings into the bore connecting to the feed lines, by means of a relative motion - preferably controlled via a stepping motor - between the pipe piece and the above bore.

Abstract: Method for making an electrode having an axial capillary bore with an intersecting bore. An extensible tube is inserted in the axial bore and a polymerizable mixture is inserted in the intersecting bore and permitted to polymerize against the tube which is stretched to facilitate removal of the tube. The tube is selected to swell under the action of the solvent and the tube is filled with solvent.

Abstract: The measuring electrode to be checked is polarized cyclically with an alternating voltage and the maximum amplitude of the electrode current as occuring during cyclical polarization is directly used as a measure for the metrologically relevant condition of the electrode.

Abstract: In a squeezed tube valve which comprises a valve block with a longitudinal groove to guide a flexible tube and a transverse groove for an electromagnetically actuated clamping bolt to shut off the tube, the crossing between the longitudinal and the transverse groove is rounded off at its edges, and the clamping force exerted by the bolt rises from zero according to an asymptotic rise function over the duration of the shutting action.

Abstract: In a capillary reference electrode with a capillary body which comprises a measuring chamber connected through an electrolytic bridge to a test sample which is adapted to be introduced into a capillary bore, the inlet orifice for the electrolyte is arranged at a point of the measuring chamber which is in a low position when the element is installed and the outlet orifice is arranged at a high position of the measuring chamber. The electrolytic bridge is formed through a communicating passage which has a substantially conical narrow end adjacent to the capillary bore with a very fine communication bore leading to the capillary bore. The resulting economy in electrolyte-consumption and absence of sensitivity in respect of potentially occuring air bubbles are further improved by providing the said communication bore with a substantially annular cross section.

Abstract: An analyzing apparatus for measuring samples of a liquid has feeding means for feeding the samples contained in sample containers to a subsequent sample conduit, the feeding means having a substantially funnel shaped filling mouth serving for fastening sample containers of very different shapes, such as syringes, pipettes or capillary tubes, and the dimensions of the outlet opening thereof varying within wide limits. A cleaning device can be used, which has a washing body which during the cleaning operation, together with the funnel shaped filling mouth, defines an annular gap adapted to match the form of the filling mouth and is providable with a cleaning medium.

Abstract: The measured values are calculated from the following equation: ##EQU1## in which X.sub.1, X.sub.i+1, X.sub.i+2 are three values of signals obtained from one electrode measured successively at equal intervals of time, namely after a latent time .tau. has elapsed.The time required for calibration and measurement in the course of a blood gas analysis can be substantially reduced by the consistent application of this procedure for obtaining the measured value for each calibration and measurement.