The invention relates to a fuel injector, in particular a common rail injector, for injecting fuel into a combustion chamber of an internal combustion engine, having a nozzle body designed for protruding into the combustion chamber and tightened to a retaining element by means of a nozzle clamping nut, and having a seal for sealing off the combustion chamber from a nozzle body area. for at least 30 minutes; recovering said trazodone; and, optionally, treating said trazodone with hydrochloric acid to obtain trazodone hydrochloride. The elements are further defined by linked scopes of work descriptions and can include contract language.