Keywords: monitoring Substances: 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) 2-4-dimethylphenylformamide (JOFDPSBOUCXJCC-UHFFFAOYSA-N) 4-Methyl-Benzotriazole (CMGDVUCDZOBDNL-UHFFFAOYSA-N) 5-Methylpyridine-3-carboxylic-acid (DJDHHXDFKSLEQY-UHFFFAOYSA-N)