Abstract: Disclosed is a separation of amphoteric molecules according to their isoelectric points, wherein a first separation according to the isoelectric points of the molecules in one ore more first strip-like separation media located on a first carrier is carried out. First separation media have a first pl range.

Abstract: Disclosed is the extraction of molecules from at least one separation medium wherein a frame with different compartments is brought in contact with the separation medium, thereby dividing the separation medium into different compartments. At least one solvent is applied into the different compartments, extracting the molecules.

Abstract: A method of reducing the effects of varying environmental conditions on a measuring instrument includes thermally insulating a measuring unit such that the effects of variations of environmental conditions on selected components of the measuring unit are substantially reduced, while allowing dissipated heat generated within the measuring unit to leave the measuring unit. The method also includes controlling a first temperature in the measuring unit by means of a control loop which includes a temperature sensor and means to influence the first temperature in the measuring unit in such a way that temperatures at locations with selected components are kept substantially constant.

Abstract: A method of reducing the effects of varying environmental conditions, such as varying temperature, on the measuring results in a measuring instrument, is disclosed as well as a corresponding measuring instrument using the method, for example an optical detector.

Abstract: A photodiode array spectrometer for determining the spectral composition of a plychromatic beam of radiation comprises diffraction means (10) which generate from the polychromatic beam a diffracted beam with a plurality of spatially separated diffracted rays of different wavelengths (.lambda..sub.1, .lambda..sub.2, .lambda..sub.3). A photodiode array (11) receives the diffracted beam whereby each photodiode intercepts a different spectral portion of the beam. A rotatable transparent plate (8) is provided in the beam path in front of the diffraction means (10) which, due to refraction of the beam upon entering and leaving the plate (8), permits to vary the direction of the beam impinging on the diffraction means (10) and therefore the direction of the diffracted beam in small steps depending on the angle of rotation of the plate (8).