FILTERED WHITE-NOISE AND REPETITIVE CHIRP BROAD-BAND QUADRUPOLAR EXCITATION FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETRY AT 1 TESLA

Radiofrequency (RF) chirp and filtered white noise are compared as wav eforms for broadband quadrupolar excitation, Ions are formed by matrix -assisted laser desorption Fourier transform ion cyclotron resonance ( FT-ICR) mass spectrometry and axialized by quadrupolar excitation, Bot h quadrupolar excitation waveforms are capable of axializing ions over a range of masses, Remeasurement efficiencies for repetitive chirp ex citation are greater than 98%. Remeasurement efficiencies for noise ex citation are lower, 80%. The duration of transients recorded using eit her broadband excitation method is several orders of magnitude longer than for ions that have not been axialized.