Keywords: high resolution mass spectrometry land use Substances: 4-Hydroxy Diclofenac (KGVXVPRLBMWZLG-UHFFFAOYSA-N) 1-(3-Trifluoromethylphenyl)-piperazine (KKIMDKMETPPURN-UHFFFAOYSA-N) MCPA (WHKUVVPPKQRRBV-UHFFFAOYSA-N)