CHARGE-REMOTE FRAGMENTATION OF ECDYSTEROIDS CONJUGATED WITH PHOSPHORIC-ACID

Successful application of tandem mass spectrometry on a series of the ecdysteroid phosphates (eddysteroids conjugated with phosphoric acid) led to general information for their characterization. The 22-phosphat es and the 2-(or 3-)phosphates can be definitely distinguished by thei r charge-remote fragmentation patterns. In the case of the 22-phosphat es, information about the side-chain moiety is readily obtained. In th e case of the 2-(or 3-)phosphates, information about the ring as well as the side-chain is readily available. Neither the positional isomers (2- and 3-phosphates) in the A-ring nor the configurational isomers ( alpha and beta) can be distinguished.