Abstract: A fluorescence detector has a light source in the form of a halogen lamp, a UV-filter which allows excitation radiation in UV to pass through, and a second filter which sorts out fluorescence radiation, and a detector which detects the through-passing fluorescence radiation. The filters comprise thin straight blocks and also function as light guides and are positioned at right angles with their extensions directed towards a point at which a tubular sample can be placed in close with the ends of the filters distal from the light source and the detector.