STRUCTURAL-ANALYSIS OF POLYOXYALKYLENEAMINES BY MATRIX-ASSISTED LASERDESORPTION IONIZATION ON AN EXTERNAL ION-SOURCE FT-ICR-MS AND NMR/

Matrix-assisted laser desorption:ionization (MALDI) and Fourier-transf orm ion cyclotron mass spectrometry (ET-ICR-R IS) are combined for the characterization of polyoxyalkleneamines. H-1 and C-13 NMR data are u sed to confirm and quantify structural assignments. Characterization o f the molecular weight distribution, chemical composition distribution , and end group distribution of amine-terminated (co-)polymers of ethy lene oxide and propylene oxide is rather complex because the convoluti on of these three entities yields an ensemble of structurally related molecules which is hard to characterize by conventional analytical tec hniques. In this study MALDI FT-ICR-MS is used to resolve intact, Nacationized, oligomer ions in the mass range From m/2 500 to 3500. This revealed the presence of various compositional distributions in the p olyoxyalkyleneamines. The individual compound masses in the molecular weight distributions were measured with a mass accuracy of <20 millima ss units, allowing end group and repeat unit determination with an acc uracy of better than 50 millimass units. NMR is used to measure the av erage end group distribution to provide insight in conformational diff erences. Zn this respect, FT-ICR-MS data and NMR data are complementar y. The combined results yield detailed information about chemical comp osition distributions of polyoxyalkyleneamines that hitherto it was no t possible to obtain with either technique separately.