Extinction Coefficient Excitation Maximum: 80000;Fluorescence Quantum Yield: 0.9 BDP FL-PEG5-acid is a BDP FL acid derivative containing a hydrophilic PEG spacer arm. BDP FL is a green-fluorescent dye and the hydrophilic PEG spacer arm increases water solubility as well as membrane permability. BDP FL dye has several characteristics that make it potentially superior in some applications, including high extinction coefficient, high fluorescence quantum yield, narrow emission bandwidth, red shift in fluorescence emission at high dye concentrations, relatively long excited-state lifetime, etc.