Abstract: A method for at least partially applying a hydrophilic polymer to a measurement channel of a sensor cartridge is provided, which sensor cartridge can be replaceably inserted in an analyzer. The measurement channel comprises at least one sensor element. The method comprises inserting the sensor cartridge into the analyzer, introducing an aqueous solution containing chitosan or a chitosan derivative into the measurement channel of the sensor cartridge, and following a residence time replacing the aqueous chitosan solution with a gaseous or liquid medium, wherein residues of the chitosan or chitosan derivatives remain on the inside surface of the measurement channel and hydrophilize the surface.

Abstract: In a method for calibrating a biosensor for the amperometric determination of creatinine in biological liquids, consisting of one electrode system each for measuring the concentrations of creatinine and creatine, with at least two calibration solutions being used, the electrode system for measuring the creatinine concentration is calibrated with a creatinine solution which, prior to the calibration measurement, was mixed in the form of an acidic solution with an alkaline buffer solution, and the electrode system for measuring the creatine concentration is calibrated with a solution in which creatinine and creatine are at a thermodynamic equilibrium.

Abstract: In a method for calibrating a biosensor for the amperometric determination of creatinine in biological liquids, consisting of one electrode system each for measuring the concentrations of creatinine and creatine, with at least two calibration solutions being used, the electrode system for measuring the creatinine concentration is calibrated with a creatinine solution which, prior to the calibration measurement, was mixed in the form of an acidic solution with an alkaline buffer solution, and the electrode system for measuring the creatine concentration is calibrated with a solution in which creatinine and creatine are at a thermodynamic equilibrium.

Abstract: In a method for calibrating a biosensor for the amperometric determination of creatinine in biological liquids, consisting of one electrode system each for measuring the concentrations of creatinine and creatine, with at least two calibration solutions being used, the electrode system for measuring the creatinine concentration is calibrated with a creatinine solution which, prior to the calibration measurement, was mixed in the form of an acidic solution with an alkaline buffer solution, and the electrode system for measuring the creatine concentration is calibrated with a solution in which creatinine and creatine are at a thermodynamic equilibrium.

Abstract: In a method for calibrating a biosensor for the amperometric determination of creatinine in biological liquids, consisting of one electrode system each for measuring the concentrations of creatinine and creatine, with at least two calibration solutions being used, the electrode system for measuring the creatinine concentration is calibrated with a creatinine solution which, prior to the calibration measurement, was mixed in the form of an acidic solution with an alkaline buffer solution, and the electrode system for measuring the creatine concentration is calibrated with a solution in which creatinine and creatine are at a thermodynamic equilibrium.

Abstract: A reagent bottle suitable for insertion into a sample analyzer features a sample discharge opening plugged by an elastic, pierceable stopper, and an air inlet. Both the sample discharge opening and the air inlet are located on the same side of the reagent bottle, the axes of the two openings running parallel to each other, such that both openings can be docked onto corresponding sampling and air inlet elements of the analyzer in one and the same working process when the reagent bottle is inserted into the analyzer. The elastic stopper is covered on its outside by a protective foil and has a recess at a puncturing site enabling the sampling element to puncture the foil more easily. Bordering on the recess of the stopper is an area which is prepunctured but offers a tight elastic seal.

Abstract: In a process for mixing two initial solutions to produce a working solution with an accurately defined mixing ratio, the two initial solutions are coarsely mixed in a first step, having a mixing ratio lying within a given range, and the value of an internal parameter of the working solution is determined in a second step. The values of this internal parameter are known and differ significantly for the two initial solutions. Then the accurate mixing ratio of the working solution is determined from the measured value of the internal parameter in a third step.

Abstract: In order to calibrate a measurement apparatus used for determining at least the pH and pCO.sub.2 values in aqueous media, two aqueous base solutions A and B with good storage stability are mixed at a defined ratio immediately prior to calibration, the desired pH and pCO.sub.2 values being provided for calibration of the measuring electrodes of the measurement apparatus only after chemical reaction of the base solutions A and B has taken place.