API-ionspray MS and MS/MS study on the structural characterization of bisbenzylisoquinoline alkaloids.

API-ionspray MS and MS/MS techniques have been utilized to elucidate the structures of 20 bisbenzylisoquinoline alkaloids, consisting of 17 diether and three monoether links of two benzyltetrahydroisoquinoline units, which were isolated and identified previously from a variety of Thalictrum sp. (Ranunculaceae family). Apparent protonated molecular ions ([M+H](+)) and very intense doubly-protonated molecular ion ([M+2H](++), 100% of relative abundance) in Q1 Scan MS spectra and prominent as well as diagnostic product ions for the structural information in MS/MS spectra were observed in nanogram quantities for all investigated alkaloids.