No fragmentation of Ion Peak with Ion Trap!

[problemeste]

We carry out an analysis by HPLC-MS Ion Trap. We get two UV peaks, each one of them has ion peak, with m/z=451. We decide to do a fragmentation of this ion but only show the fragmentation peaks for one of them! What happens?

It has nothing to do with Cutoff....

[lmh]

Probably they are two completely different things that happen to have the same mass. If you don't have fragments in that the ion remains as a parent, you will have to try a greater collision energy. If you have an empty spectrum with no ions at all, then several things may have gone wrong. The major fragments may be smaller than the lowest mass your trap could retain while fragmenting. Alternatively, the parent ion may be poorly trapped. To test the latter, you could try "fragmentation" with no energy.

[problemeste]

Thanks!

But what do u mean when u talk about "fragmentation with no energy"? How can I modify this parameter (Ion Trap Bruker Software)?