Variables: concentration electric_conductivity pH Substances: 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N) 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 4-Acetamidoantipyrin ( N-Acetyl-4-Aminoantipyrin 4-AAA) (OIAGWXKSCXPNNZ-UHFFFAOYSA-N)