EFFECTS OF CAPACITIVE COUPLING ON ION REMEASUREMENT USING QUADRUPOLAREXCITATION IN HIGH-RESOLUTION FTICR SPECTROMETRY

Axial ejection is found to be the principal cause of the loss of ions during Fourier transform mass spectrometry remeasurement experiments, Ion remeasurement improves to near unit efficiency when an open-ended cylindrical analyzer cell is used with capacitive coupling of the exci tation signal to the adjacent trapping plates. With capacitive couplin g enabled for the entire experiment; 100% remeasurement efficiency is observed over a narrow mass range (10 Da) for 200 scans of ions of pol y(ethylene glycol) formed by internal matrix-assisted laser desorption /ionization. Greater than 99.5% efficiency per remeasurement cycle has been achieved for wide mass range (1000 Da) remeasurement with capaci tive coupling enabled. Further evidence for axial ejection during reme asurement comes from a comparison of remeasurement efficiencies obtain ed at different trapping potentials.