Fluorescamine is a spiro compound that is not fluorescent itself, but reacts with primary amines to form highly fluorescent products, i.e. it is fluorogenic. It hence has been used as a reagent for the detection of amines and peptides. 1-100 μg of protein and down to 10 pg of protein can be detected. Once bound to protein the excitation wavelength is 381 nm (near ultraviolet) and the emission wavelength is 470 nm (blue). This method is found to suffer from high blanks resulting from a high rate of hydrolysis due to requiring a large excess concentration. Alternative methods are based on ortho-phthalaldehyde (OPA), Ellman's reagent (DTNB), or epicocconone.