Post-column derivatization for capillary electrophoresis using naphthalene-2,3-dicarboxaldehyde and 2-mercaptoethanol

A reagent consisting of naphthalene-2,3-dicarboxaldehyde and 2-mercaptoethanol has been investigated for post-column derivatization of amines with a gap-based reactor developed for capillary electrophoresis and laser-induced fluorescence detection. Separation and detection of a wide range of compounds has been demonstrated including neuropeptides, catecholamines, amino acids and proteins. Compounds derivatized with this reagent have been detected by laser-induced fluorescence using excitation with the He-Cd laser (442 nm line) and could also be detected using an Ar ion laser (458 nm line). Mass detection limits obtained with this reagent and post-column derivatization for glycine and transferrin are 330 and 13 mol, respectively. Sensitive detection of lysine has also been demonstrated with this reagent. Electropherograms for homogenate samples of a snail brain and for single mammalian cells have been obtained using post-column derivatization with this reagent and laser-induced fluorescence detection