5-FAM-PEO8 SE (full name: 5-Carboxyfluorescein-PEO8 propionate succinimidyl ester) has an approximately 32 Angstrom water-soluble PEG spacer that separates fluorescein and the amine-reactive SE group. &lamba;Ex/&lamba; Em(pH9) = 494/521 nm Yellow orange solid soluble in DMF, DMSO, or pH 6.5 buffer Store at -20°C and protect from light C44H52N2O18 MW:896.89