Variables: pH electric_conductivity Keywords: monitoring Substances: 1-Naphthylacetic acid (PRPINYUDVPFIRX-UHFFFAOYSA-N) 1-Propanesulfonate (KCXFHTAICRTXLI-UHFFFAOYSA-N) 3-5-Diamino-2-4-6-triiodobenzoic acid (GOQCZMZLABPEME-UHFFFAOYSA-N)