Keywords: monitoring Substances: 5-Methylpyridine-3-carboxylic-acid (DJDHHXDFKSLEQY-UHFFFAOYSA-N) 1-3-Dimethyl-2-imidazolidinon (CYSGHNMQYZDMIA-UHFFFAOYSA-N) 4-Hydroxy Diclofenac (KGVXVPRLBMWZLG-UHFFFAOYSA-N) Acetochlor (VTNQPKFIQCLBDU-UHFFFAOYSA-N)