Importance

Loading Importance Indicators...

Abstract

A mass spectrometry method in which trapped ions are excited in non-consecutive mass order for detection. The ions can be ejected from the trap in non-consecutive mass order for detection at an external detector, or detected at an in-trap detector in non-consecutive mass order before they leave the trap. In one embodiment, a sequence of supplemental AC voltage signals, each having a frequency matching a resonant frequency of one of the ions to be detected, is applied to a trap to resonate trapped ions in non-consecutive mass order. In another embodiment, the amplitude of the fundamental RF trapping voltage is varied while a sequence of supplemental AC voltage signals is applied to a trap to resonate trapped ions (or cause them to become unstable) in non-consecutive mass order. Another embodiment enables detection of both high mass ions and low mass ions with improved high mass resolution, when the ions are stably trapped in a three-dimensional quadrupole trapped field. In the latter embodiment, the amplitude of the fundamental RF trapping voltage is controlled to increase the Mathieu q coordinate of a high mass ion, and the high mass ion is then excited for detection.

Loading the Abstract Image...

First Claim