Keywords: high resolution mass spectrometry Substances: Acesulfame (YGCFIWIQZPHFLU-UHFFFAOYSA-N) 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) 4-Methyl-Benzotriazole (CMGDVUCDZOBDNL-UHFFFAOYSA-N) Acetamipride (WCXDHFDTOYPNIE-RIYZIHGNSA-N)