Abstract: A TIRFM-capable microscope including: a light source that generates/emits incoherent excitation light onto an optical path that includes a first projection lens system, a spatial filter, a second projection lens system and an objective. The TIRFM-capable microscope also includes a controller; wherein the first projection lens system projects excitation light onto the spatial filter that filters the excitation light with two-dimensional patterns, the spatial filter lies in a plane conjugate to a back focal plane of the objective which includes an objective lens that directs excitation light onto and receives fluorescent light from the sample, wherein, for a numerical aperture NAObj of the objective and a refractive index nspec of the sample NAObj>nspec, and the controller activates the spatial filter to select/generate various two-dimensional patterns and selects/adjusts the position/shape/size of the pattern such that TIRF illumination of the sample is generated.

Abstract: A TIRFM-capable microscope including: a light source that generates/emits incoherent excitation light onto an optical path that includes a first projection lens system, a spatial filter, a second projection lens system and an objective. The TIRFM-capable microscope also includes a controller; wherein the first projection lens system projects excitation light onto the spatial filter that filters the excitation light with two-dimensional patterns, the spatial filter lies in a plane conjugate to a back focal plane of the objective which includes an objective lens that directs excitation light onto and receives fluorescent light from the sample, wherein, for a numerical aperture NAObj of the objective and a refractive index nspec of the sample NAObj>nspec, and the controller activates the spatial filter to select/generate various two-dimensional patterns and selects/adjusts the position/shape/size of the pattern such that TIRF illumination of the sample is generated.

Abstract: A method for quantitative and/or qualitative determination of germs in a liquid sample comprises the steps of: (1) passing the sample through a filter thereby depositing the germs on a major portion of the filter so that a minor portion of the filter is free of germ deposits; (2) applying a fluorescent label to at least a portion of the deposited germs; (3) determining the presence and/or the amount of labeled germs by fluorescent reflection photometry. The method according to the present invention is suitable, for example, for quantitative and/or qualitative determination of germs in foodstuffs, surfactant-containing products such as washing and cleaning agents, surface treatment agents, dispersion products, cosmetics, hygiene products and personal care products, pharmaceuticals, adhesives, coolant lubricants, coatings and coating coagulations, as well as raw materials and starting materials for the aforesaid products.