The Possibility of X-Type Ions With Linear Saturated Non-Reducing Termini Dissociated From Potasiated Saikosaponins

MS dissociation of potassiated parent ions may play an important role in the structural characterization for some compounds but was seldom reported.

Four isomeric saikosaponins, i.e., a, d, b1, and b2, were characterized through LC/IT-TOFMS analysis in the positive ionization mode. And their [M + H + K]²⁺ and [M + K]⁺ ions were selected for further dissociation.

Here was presented the first report of the mass dissociation of potasiated saikosaponins, i.e., [M + H + K]²⁺ and [M + K]⁺, both of which, according to our cautious analysis, produced the potasiated X-type ions with linear, saturated nonreducing termini.

The potasiated rather than sodiated saikosaponins gave informative A- and X-type fragment ions. The speculative potasiated X-type ions with linear, saturated nonreducing termini were not reported previously as far as we knew, which may make an essential complement to the current knowledge of mass fragmentation.