Variables: pH Substances: 4-Acetamidoantipyrin ( N-Acetyl-4-Aminoantipyrin 4-AAA) (OIAGWXKSCXPNNZ-UHFFFAOYSA-N) 1-3-Dimethyl-2-imidazolidinon (CYSGHNMQYZDMIA-UHFFFAOYSA-N) 1-Naphthylacetic acid (PRPINYUDVPFIRX-UHFFFAOYSA-N) Keywords: monitoring