Jackson Immuno Research Inc.
specializing in secondary antibodies and conjugates
Select Science Logo

Whole IgG Affinity-Purified Secondary Antibodies

"I have used a wide variety of secondaries and Jackson ImmunoResearch has consistently been the best. The fluorophores are bright and stable and their selective (x reactivity removed) secondaries have always shown species specificity in multiple labeling."

Janet Duerr, Ohio University

Rating: 5.0

Leave a Review

Fluorescein, FITC/DTAF

FITC Technical Information

FITC (Fluorescein isothiocyanate) is the form of fluorescein used for conjugation to all JIR antibodies and purified proteins, with the exception of streptavidin. Fluorescein conjugates absorb light maximally at 492 nm and fluoresce maximally at 520 nm. Although less bright than other green-fluorescing dyes, FITC is a widely used fluorophore for applications that don’t require exquisite sensitivity. The major disadvantage of fluorescein is its rapid photobleaching (fading), which can be mitigated by the use of an anti-fading agent in the mounting medium. An alternative choice for many applications involving FITC is Alexa Fluor® 488 because it is brighter and more photostable.

DTAF (Dichlorotriazinylamino fluorescein) is another form of fluorescein, with excitation and emission peaks identical to those of FITC. Jackson ImmunoResearch uses DTAF (instead of FITC) for conjugation with streptavidin, since fluorescence from FITC is greatly quenched after conjugation with streptavidin. This phenomenon is unique to streptavidin, and is not observed with antibodies.

FITC is available conjugated to:

Excitation Peak (nm) Emission Peak (nm)
Fluorescein, FITC/DTAF 493 519

Spectra Viewer

Use the spectra viewer below to compare FITC with other fluorophores, along with instrument specifics (laser/filter) for suitability in your assay.

Read our blog about selecting fluorophores using the Spectra Viewer