Electrospray mass spectrometry determination of linear and cyclic oligomers of polyamide-6

Analysis of linear and cyclic polyamide-6 (PA-6) oligomer mixtures is an of ten needed task, that requires expensive equipment and/or chemicals or invo lved chemical procedures. We present an analytical method using electrospra y ionization-mass spectrometry (ESI-MS) that has none of the mentioned diff iculties. Measurements were performed on simple acidic aqueous solutions of oligomers. The method allowed qualitative and quantitative characterizatio n of cyclic and Linear oligomers up to octamer. Scanning for both the posit ive, as well as negative ion fragments was used. Signal vs, concentration r esponses were determined for a number of lower oligomers. The method has th e advantage of short analysis times and the use of relatively accessible in strumentation. (C) 2001 Elsevier Science Ltd. All rights reserved.