Electrostatic mass spectrometer with encoded frequent pulses

摘要

A method, apparatus and algorithms are disclosed for operating an open electrostatic trap (E-trap) or a multi-pass TOF mass spectrometer with an extended flight path. A string of start pulses with non equal time intervals is employed for triggering ion packet injection into the analyzer, a long spectrum is acquired to accept ions from the entire string and a true spectrum is reconstructed by eliminating or accounting overlapping signals at the data analysis stage while using logical analysis of peak groups. The method is particularly useful for tandem mass spectrometry wherein spectra are sparse. The method improves the duty cycle, the dynamic range and the space charge throughput of the analyzer and of the detector, so as the response time of the E-trap analyzer. It allows flight extension without degrading E-trap sensitivity.

主权项

1. An electrostatic mass spectrometer comprising:
(a) a pulsed ion source for ion packet formation; (b) an ion detector; (c) a multi-pass electrostatic mass analyzer providing an ion packet passage though said analyzer in a Z-direction and isochronous ion oscillations in the locally orthogonal direction X; (d) a pulse string generator for triggering said pulsed ion source or pulsed converter with time intervals between any pair of start pulses being unique within the peak time width AT on the detector; (e) a data acquisition system recording of detector signal at the duration of said pulse string and for summing spectra corresponding to multiple pulse strings; (f) a main pulse generator for triggering both—said data acquisition system and said pulse string generator; and (g) a spectral decoder for reconstructing mass spectra based on the detector signal and on the information on the preset time intervals of said start pulses.