The electron ionisation induced decomposition pathways of a series of new c
oumarins, three psoralens, one allopsoralen and one angelicine have been st
udied in detail with the aid of mass analysed ion kinetic energy spectromet
ry, The examined compounds exhibit decomposition patterns well related to t
heir structures and the characterisation of some isomer pairs has been obta
ined. (C) 1998 John Wiley Br Sons, Ltd.