Substances: 4-Methyl-Benzotriazole (CMGDVUCDZOBDNL-UHFFFAOYSA-N) 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) Acetochlor-OXA (OTKTUNJJKYTOFF-UHFFFAOYSA-N) Keywords: high resolution mass spectrometry