Leica, AD-550-25, ATTO 550 Carboxy Fluorescent Label 5 mg

Optical properties
λ abs = 554 nm
ε max = 1.2×10 5 M -1 cm -1
λ fl = 576 nm
n fl = 80 %
τ fl = 3.6 ns
CF 260 = ε 260 /ε max = 0.23
CF 280 = ε 280 / ε max = 0.10
ATTO 550 is a novel fluorescent label related to the well-known dyes Rhodamine 6G and Rhodamine B. Characteristic features of the label are strong absorption, high fluorescence quantum yield, and high thermal and photo-stability.
The dye is moderately hydrophilic. ATTO 550 is a cationic dye. After coupling to a substrate the dye carries a net electrical charge of +1. As supplied ATTO 550 consists of three isomers with practically identical absorption and fluorescence.
The fluorescence is excited most efficiently in the range 540 - 565 nm.