Mass spectrometer

Abstract

A mass spectrometry method is disclosed in which a voltage signal from an ion detector is analyzed. The second order differential of each voltage signal was obtained and the onset and end times of the observed voltage peaks were determined. The intensity and average time of each voltage peak are then determined and the intensity and time values ​​are stored. An intermediate composite mass spectrum was then formed by combining the intensity and time values ​​associated with each voltage peak observed from multiple experimental runs. Each time and intensity data pair is then integrated to produce a smooth continuum. The continuum can then be further processed by determining the second differential of the continuum. The start and end times of mass peaks observed in a continuum mass spectrum can be determined. The intensity and mass-to-charge ratio of each mass peak observed in the continuum can then be determined. A final discrete mass spectrum including only the intensity values ​​and mass-to-charge ratios for each ion can then be displayed or output.

Description

technical field [0001] The invention relates to a mass spectrometer and a mass spectrometry method. Background technique [0002] One known method of obtaining a mass spectrum is to use a fast analog-to-digital converter (ADC) to record the output signal from the ion detector of the mass analyzer as a function of time. It is known to use analog-to-digital converters with scanning magnetic sector mass analyzers, scanning quadrupole mass analyzers or ion trap mass analyzers. [0003] If the mass analyzer is scanned very quickly over a relatively long period of time (eg, over the entire duration of a chromatographic separation experiment run), it is clear that a very large amount of mass spectral data will be collected if an analog-to-digital converter is used. Storing and processing large amounts of mass spectrometry data requires large memory, which is disadvantageous. Additionally, large amounts of data have the effect of slowing down subsequent data processing. This can ...

AI Technical Summary

Problems solved by technology

However, one disadvantage of time-to-digital converters is that they do not output intensity values ​​associated with ion arrival events

[0007] A disadvantage of conventional time-of-flight mass analyzers is that the many individual spectra that are histogrammed to form the final mass spectrum may involve acquisitions that record few or no ion arrival events

[0012] However, an important disadvantage of conventional time-to-flight mass analyzers comprising an ion detector with a time-to-digital converter system is that the time-to-digital converter cannot distinguish between signals due to a single ion arriving at the ion detector and signals due to multiple ions arriving simultaneously The signal generated by the detector

[0013] Known ion detectors incorporating time-to-digital converter systems also suffer from the problem that they exhibit a recovery time after an ion arrival event is registered, during which time the signal must drop below a predetermined voltage signal threshold

Consequently, relatively weak ion signals may be masked, which may result in relatively poor detection limits compared to those obtainable using time-to-digital converter-based systems

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