Product name: Fluorescein isothiocyanate (FITC)
Synonym: 5-isothiocyanatofluorescein, Fluorescein isothiocyanate isomer I, 5-FITC
Catalog #: 8601014
CAS No.: 3326-32-7
Molecular Formula: C21H11NO5S
Molecular Weight: 389.38
Compound ID: 18730
Description: FITC is the fluorescein derivative that reacts covalently with amine groups at alkaline pH. Compounds containing thiol and/or amino groups (mercaptoethanol, glutathione, cysteine, ethanolamine, glycine) were studied with respect to their reactivity towards fluorescein isothiocyanate (followed spectrophotometrically at 504 and 412 nm), stability of product and long-wave absorption maximum of the fluorescein residue attached. Thiol groups reacted by far more readily than amino groups. A specific effect was observed with cysteine, indicating an intramolecular transfer of the fluorescein residue from SH to NH2.