| 摘要 |
A method of mass spectrometry comprises providing a collision or reaction cell (e.g. RF quadrupole ion guide or ion trap) and causing precursor ions to collide, react, dissociate or fragment so as to form product or daughter ions. A broadband excitation with frequency notches is applied to the collision or reaction cell to eject the product ions from the collision or reaction region, and a device is arranged to determine the times when the fragment or product ions are ejected. Different precursor ions (A, B) may react with reagent ion C or fragment to give different product ions (D, E) which are preferably generated and ejected at different times. The missing notch frequencies may be around the secular frequencies of the precursor ions (A, B) and reagent ions (C) to trap the precursor and reagent ions. The invention allows different precursor ions (A, B) to be differentiated based on their reaction times. |
