Variables: dissolved_organic_carbon electric_conductivity pH Substances: 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N) 1-Naphthylacetic acid (PRPINYUDVPFIRX-UHFFFAOYSA-N) Keywords: high resolution mass spectrometry