Variables: electric_conductivity pH Keywords: high resolution mass spectrometry land use Substances: 4-Dimethylaminoantipyrin (Aminopyrin) (RMMXTBMQSGEXHJ-UHFFFAOYSA-N) 1-Naphthylacetic acid (PRPINYUDVPFIRX-UHFFFAOYSA-N) 2 -2 -Difluorodeoxyuridin (FIRDBEQIJQERSE-QPPQHZFASA-N)