DAF-FM / 3-Amino-4-(N-methylamino)-2', 7'-difluorofluoresceine

3-Amino-4-(N-methylamino)-2',7'-difluorofluorescein diacetate. DAF-FM DA is an important reagent for quantification of low concentrations of nitric oxide in solution. This compound is essentially nonfluorescent until it reacts with NO to form a fluorescent benzotriazole. DAF-FM DA has an excitation/emission maxima of 495nm.

DAF-FM Specifications:
• Ex/Em of DAF-FM: ~495/515 nm
• Lyophilized product should be dissolved using DMSO and then added to an aqueous buffer to create a working solution. 
• DAF-FM diacetate is cell permeant and passively diffuses across cellular membranes; once inside the cell, it is converted to a cell-impermeant form! 
• Buffers containing bovine serum albumin (BSA) and phenol red may affect the fluorescence and should be used with caution.
• The fluorescence quantum yield of DAF-FM is ~0.005, but increases about 160-fold, to ~0.81, after reacting with NO.

Important Advantages of DAF-FM over DAF-2
The spectra of the NO adduct of DAF-FM are independent of pH above pH 5.5. Also, the NO adduct of DAF-FM is significantly more photostable than that of DAF-2 >, which means additional time for image capture. Finally, DAF-FM is a more sensitive reagent for NO than is DAF-2 (NO detection limit for DAF-FM ~3nM versus ~5nM for DAF-2).