Dabcyl-KTSAVLQSGFRKME-Edans is a peptide with fluorescence modification. The N-terminal Dabcyl acid of the peptide chain and the C-terminal Edans will undergo fluorescence quenching, but these two fluoresceins will undergo color reaction separately. Dabcyl-KTSAVLQSGFRKME-Edans is one of the raw materials for the detection of COVID-19. It is used to detect the main protease of the new SARS-CoV-2, 3C-like proteinase (3C-like Proteinase, 3CLPro).