Invitrogen - Molecular Probes

Data for D6566

212.15

DMSO, DMF

Abs

358

18,000

452

pH 9

see Notes

<1>	Spectra of hydroxycoumarins are pH-dependent. Below the pK_a, Abs shifts to shorter wavelengths (325–340 nm) and fluorescence intensity decreases. Approximate pK_a values are 7.8 (H189, C2111), 7.5 (H185), 7.3 (T659) and 4.9 (D6566, C12881).
<2>	The fluorescence quantum yield of DiFMU (D6566) is 0.89 measured in 0.1 M phosphate buffer, pH 10.