Variables: dissolved_oygen concentration pH Keywords: MetFrag high resolution mass spectrometry Systems: groundwater Substances: 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N) 1-Methyl-Benzotriazole (HXQHRUJXQJEGER-UHFFFAOYSA-N) Acetochlor-ESA (HXAIQOCRALNGKB-UHFFFAOYSA-N)