Variables: electric_conductivity dissolved_organic_carbon Substances: 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 2-Aminobenzimidazole (JWYUFVNJZUSCSM-UHFFFAOYSA-N) 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N)