Variables: electric_conductivity Substances: 4-Formylaminoantipyrin (4-FAA) (WSJBSKRPKADYRQ-UHFFFAOYSA-N) 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N)