| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration of a signal intensity of MS/MS spectrum due to a secondary dissociation of primary fragment ions generated by photodissociation.SOLUTION: An exciting laser beam for bringing about photodissociation is irradiated on a position away from a center of a capturing region A in an ion trap 1 and simultaneously an excitation signal for exciting precursor ions selectively is impressed on end cap electrodes 12, 13. Due to an action of an excited electric field thus formed, the precursor ions vibrate greatly and go out of the capturing region A and cross an excitation light irradiating region B and thereby dissociation is brought about when irradiated with the exciting laser beam. Meanwhile, since fragment ions generated by the dissociation receive hardly any action of the excitation electric field and remain in the capturing region A and do not enter the excitation light irradiating region B. As a result, the fragment ions hardly receive the exciting laser beam and a secondary dissociation is hardly caused. |
