The ATTO-TAG FQ reagent allows the ultrasensitive detection of primary amines. This reagent is available as a standalone product or as a component of an amine-derivatization kit (A-2334). Because ATTO-TAG FQ is nonfluorescent in the unreacted state and reacts specifically with amines to form highly fluorescent conjugates, it is particularly well-suited to the derivatization of peptides, amino acids, aminated sugars and other amine-containing molecules for detection by capillary electrophoresis with laser-induced fluorescence (LIF). Recently, researchers described a simple method in which the ATTO-TAG FQ reagent was used to derivatize very dilute solutions (10^-8 M) of peptides.