As part of our quality control, we conducted ESI-MS analysis on the chemically acetylated purified protein. The presence of a surprisingly high number of peaks with diverse mass differences posed a puzzle. However, through our R-package, we successfully identified multiple acetylation sites (AX, where X represents the number of acetylation sites). Additionally, we determined the presence of both eGFP with and without the formed chromophore (-CRO) within the analyzed samples.