Abstract: A method for cleaning at least one filter material, in particular a filter material used in the production of a respiratory protection mask (M), comprising the step of subjecting this filter material to a supercritical fluid, preferably supercritical CO2, with a density of less than 0.3 g/ml.

Abstract: The present invention concerns the field of microreaction devices and of micro-process engineering. It particularly involves devices having micro-channels (internal chambers of micrometric to submicrometric dimensions) for conveying chemical or biochemical mixtures and/or reactions. More specifically, such devices are optimized to achieve high temperature and pressure stresses (i.e. 500° C. and 500 bar). For observation and analysis purposes, the microreaction devices have a wide range of transparency in terms of wavelengths. The subject matter of the present invention relates to a microfluid or microreactor device made of transparent sapphire, preferably in the wavelength range of 150 to 6500 nm, its manufacturing method and to its use.