Keywords: MetFrag micropollutants Substances: 4-Aminopyrin (4-Aminoantipyrin 4-AA) (RLFWWDJHLFCNIJ-UHFFFAOYSA-N) 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 1-3-Dimethyl-2-imidazolidinon (CYSGHNMQYZDMIA-UHFFFAOYSA-N)