Derivatization by forming schiff bases in the study of synthetic polymers bearing amino groups by MALDI mass spectrometry

A new approach is proposed to the determination of a number of primary amino groups in polymers. It involves the formation of Schiff bases in reactions with carbonyl compounds followed by MALDI mass spectrometry study. The reaction with 2,3-dihydroxybenzaldehyde appeared to be the most efficient for polyethyleneimine derivatization. This may be due to the better co-crystallization of the matrix (2,5-dihy-droxybenzoic acid, DHB) with the polymer by the imine fragment with the structure close to that of the matrix. The proposed method today is the only one for determining the number of NH 2 groups in branched polyethylenimine molecules at the molecular level. © 2012 Pleiades Publishing, Ltd.