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Fluorescein

Fluorescein (Ex-Max 494 nm/Em-Max 512 nm)

Fluorescein is an organic fluorophore first synthesized by Aldolf Bayer in 1871. FITC, an amine-reactive derivative, is also a commonly used name for this dye. It has an excitation peak at 494 nm and an emission peak at 512 nm.

Excitation & emission spectra

400450500550600650700750800

Key facts

Excitation maximum
494 nm
Emission maximum
512 nm
Optimal laser line
488
Optimal filter
525/50
Relative brightness
1 of 5
Extinction coefficient
70000
Commercial antibodies
10.5k from 8 suppliers

Fluorescein has an excitation maximum at 494 nm and an emission maximum at 512 nm, a Stokes shift of 18 nm. Its extinction coefficient is 70000 M⁻¹cm⁻¹. It is optimally excited by the 488 laser line.

Frequently asked questions

What is Fluorescein?
Fluorescein is an organic fluorophore first synthesized by Aldolf Bayer in 1871. FITC, an amine-reactive derivative, is also a commonly used name for this dye. It has an excitation peak at 494 nm and an emission peak at 512 nm.
What laser excites Fluorescein?
Fluorescein is optimally excited by the 488 laser line. Its excitation maximum is 494 nm.
What filter should I use to detect Fluorescein?
A 525/50 filter captures the peak of the Fluorescein emission near 512 nm with minimal spillover.
How bright is Fluorescein?
Fluorescein has a relative brightness of 1 out of 5.
How many antibodies are available conjugated to Fluorescein?
FluoroFinder tracks 10543 commercially available Fluorescein conjugates, searchable by target, clone, host and application.