ATTO 620 belongs to a new generation of fluorescent labels for the red spectral region. Characteristic features of the label are strong absorption, high fluorescence quantum yield, high thermal and photostability, and only little triplet formation. In common with most dye labels, absorption and fluorescence are independent of pH, at least in the range of pH 4 to 11, used in typical applications.

ATTO 620 and its derivatives are supplied as solvent-free perchlorate salts. The dye is moderately hydrophilic. Its NHS-ester and maleimide show excellent solubility in polar solvents like DMF, DMSO or acetonitrile. For details of coupling see our recommended labeling procedure (PDF). The fluorescence is excited most efficiently in the range 600 - 630 nm.