Abstract: An optical measurement system for determining transmitted radiation and scattered radiation in a liquid sample contained in a capillary tube and subject to measurement radiation, is provided with a first detector picking up transmitted radiation, which is positioned close to or on the axis of the beam of measurement radiation. There is further provided a second detector for picking up scattered radiation, which is positioned at a distance from the first detector in the direction of the capillary axis. The two detectors lie on different sides of a plane which contains the capillary axis and is normal to the axis of the measurement radiation.

Abstract: A control or calibration standard for use with instruments for the optical measurement of the hemoglobin content in blood samples, features scattering particles or beads dispersed in aqueous electrolyte solution. To prevent sedimentation of the beads during storage, they have a mean diameter of <0.6 &mgr;m, preferably about 0.3 &mgr;m, and a volume concentration of <1%, preferably <0.3%. To prevent long term agglomeration, a non-ionic surfactant with an added antioxidant can be included in the formulation.

Abstract: In order to reduce the measuring volume in a device for measuring chemical and physical parameters of liquid or gaseous media by means of optical sensor elements whose optodes may be replaced easily, a measuring unit with a sample channel is provided which may be inserted into a supporting frame of the device and which may be connected to ingoing and outgoing sample lines via capillary bores. The measuring unit contains a sensor carrier forming the boundary of the sample channel on one side, which sensor carrier has bores holding the optodes. The indicator film of each individual optode is situated in the plane of the sensor carrier facing the sample channel.