Characterization of supramolecular complexes by high resolution electrospray ionization mass spectrometry

High resolution mass spectrometry on time-of-flight (TOF) and ion trap (IT) mass spectrometers Is used for the qualitative speciation of a heterodimetallic triple-stranded helicate [EuFe(L-1)(3)](CIO4)(5) and a toroidal complex [Ni-3(L-2)(3)](CIO4)(6) (= circular single-stranded helicate) dissolved in acetonitrile, The resolution of about 5000 at peak width at half height using ion trap mass spectrometry (ITMS) and time-of-flight mass spectrometry (TOFMS) combined with electrospray ionization (ESI) is sufficient to resolve sextuply charged ions leading to a straightforward characterization of the complexes in solution. The ESI-MS response is influenced by the interface design, particularly for the heated capillary interface which requires optimized conditions for the study of non-covalent complexes, Copyright (C) 1999 John Wiley & Sons, Ltd.