Variables: pH electric_conductivity concentration Substances: 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 1-[(4-Chlorophenyl)phenylmethyl]piperazine (UZKBSZSTDQSMDR UHFFFAOYSA-N) Systems: groundwater Keywords: monitoring MetFrag high resolution mass spectrometry