XFD488 NHS Ester-UltraPure Grade *XFD488 Same Structure to Alexa Fluor(TM) 488*

Molecular weight: 643.40. Excitation (nm): 499. Emission (nm): 520. Extinction coefficient (cm-1 M-1): 73000. Quantum yield: 0.92. Correction factor (280 nm): 0.11. XFD488 is manufactured by AAT Bioquest, and it has the same chemical structure of Alexa Fluor(R) 488 (Alexa Fluor(R) is the trademark of ThermoFisher). XFD488 NHS Ester (Succinimidyl Ester) has the same molecule as Alexa Fluor(R) 488 NHS Ester (#A20000 and A20100 from ThermoFisher). It is a bright green-fluorescent dye optimal for use with the 488 nm Argon laser. XFD488 dye is water soluble and pH-insensitive from pH 4 to pH 10. XFD488 NHS ester (or succinimidyl ester) is the most convenient amine-reactive form for conjugating this dye to a protein or antibody. Although the Alexa Fluor(R) 488 NHS Ester is one of the most common green fluorescent labeling dyes, its purity has been quite challenging. ThermoFisher provides it with purity of ~50-60% while a few other vendors offer it at even lower purities. Among all the impurities, we noted that the Bis-NHS ester of XFD488 is quite detrimental since it could give a non-fluorescent product. This high purity XFD488 NHS ester is free of the detrimental XFD488 Bis-NHS ester impurity with the minimal purity of >75%.