Table 1.5 Fluorescence quantum yields (QY) and lifetimes (τ) for Alexa Fluor dyes.

Alexa Fluor Dye * QY † τ (ns) ‡
Alexa Fluor 488 0.92 4.1 §
Alexa Fluor 532 0.61 2.5
Alexa Fluor 546 0.79 4.1
Alexa Fluor 555 0.10 0.3
Alexa Fluor 568 0.69 3.6 §
Alexa Fluor 594 0.66 3.9 §
Alexa Fluor 647 0.33 1.0
Alexa Fluor 660 0.37 1.2 **
Alexa Fluor 680 0.36 1.2
Alexa Fluor 700 0.25 1.0
Alexa Fluor 750 0.12 0.7
* Measurements were made on free succinimidyl ester derivatives in aqueous solutiuons. † For Alexa Fluor 488, Alexa Fluor 532, Alexa Fluor 546, Alexa Fluor 555, Alexa Fluor 568, Alexa Fluor 594 and Alexa Fluor 647 dyes, QY measurements were made in PBS (50 mM potassium phosphate, 150 mM NaCl, pH 7.2) at 22°C relative to fluorescein in 0.01 M NaOH (QY = 0.92). For Alexa Fluor 660, Alexa Fluor 680, Alexa Fluor 700 and Alexa Fluor 750 dyes, QY measurements were made in PBS (50 mM potassium phosphate, 150 mM NaCl, pH 7.2) at 22°C relative to Alexa Fluor 647 succinimidyl ester in PBS (QY = 0.33). ‡ Except for the footnoted values, lifetime measurements were made in water at 22°C, data provided by ISS Inc. (Champaign, IL). § Lifetime measurements were provided by the SPEX Fluorescence Group, Horiba Jobin Yvon Inc. ** Lifetime measurement was made in pH 7.5 buffer at 20°C by Pierre-Alain Muller, Max Planck Institute for Biophysical Chemistry, Göttingen.
For Research Use Only. Not for use in diagnostic procedures.