Substances: 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) 2-Aminobenzimidazole (JWYUFVNJZUSCSM-UHFFFAOYSA-N) 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N) Keywords: monitoring micropollutants high resolution mass spectrometry