Process for marking liquids, e.g. fuels

摘要

The markers used in a process for marking liquids absorb in the 600-1200 nm spectral region thus emitting fluorescent radiation and have no overlapping absorption regions. One of the markers has a wavelength of more than 850 nm. An Independent claim is also included for a process for detecting markers in liquids which have already been marked comprising using radiation sources which emit in the absorption regions of the markers. The radiation sources are semiconductor laser, semiconductor diode or solid body laser.