Variables: pH Keywords: monitoring Substances: 5-Fluorouracil (GHASVSINZRGABV-UHFFFAOYSA-N) 1-(3-Chlorophenyl)-piperazin (VHFVKMTVMIZMIK-UHFFFAOYSA-N) 2-4-D (OVSKIKFHRZPJSS-UHFFFAOYSA-N)