Description: The pKa of 5-carboxy-2',7'-dichlorosulfonefluorescein is near 4 and thus the dye is potentially an excellent pH indicator for acidic organelles.
&lamba;Ex/&lamba; Em= 509/532nm (pH 9)
ε = 92,000
Yellow solid soluble in DMSO, DMF or a buffer (pH >6)