A NEW OPERATING MODE OF A QUADRUPOLE ION-TRAP IN MASS-SPECTROMETRY .1. SIGNAL VISIBILITY

We explain a new operating mode of a quadrupole ion trap in mass spectrometry using a Fourier transform technique without additional excitation of ion motion. We introduce a mathematical formalism to describe the operating mode. Theoretical calculations are made to show the shape of the spectrum. We give an estimation of the signal-to-noise ratio with a single ion species at the secular frequency. In the case of two ion species, we notice the influence of the most abundant species over the other. Experimental results confirm the theoretical predictions and show the very good sensitivity of this method, even with few confined ions.