Matrix-assisted laser desorption/ionization collision-induced dissociationof linear single oligomers of nylon-6

Matrix-assisted laser desorption/ionization, collision induced-dissociation (MALDI-CID) has been used to obtain structural information for linear sing le oligomers of nylon-6. The effects of matrix and cationization agent in M ALDI-CID analysis have been investigated. Fragmentation mechanisms are prop osed for the series of ions that are observed in the MALDI-CID spectra of t he hexamer, octamer and dodecamer. Fragmentation processes observed in the MALDI-CID spectra include cleavage of the end groups followed by dissociati on of the m/z 113 unit. Cleavage of the oligamide chain occurs at the amide linkage, as well as at adjacent bonds. For the four matrices and three cat ionization agents investigated, 2,5-dihydroxybenzoic acid and sodium chlori de showed the best performance for MALDI-CID analysis of the dodecamer. In addition, yields of the fragment ions in MALDI-CID spectra were found to be dependent on the chain length distribution. Copyright (C) 2001 John Wiley & Sons, Ltd.