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Theoretical Study of High-Order Velocity Focusing Achieved with Single-Stage Reflectron Time-of-Flight Mass Spectrometry

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide This study explores unexplained fundamental principles of reflectron time-of-flight (R-TOF) mass spectrometry (MS). Conventional calculations focusing on the ion trajectory in reflectors concluded that multistage reflectors are necessary to achieve second-order velocity focusing at ion detectors. This study demonstrates that in an instrument equipped with a matrix-assisted laser desorption/ionization (MALDI) ion source a single-stage reflector can achieve second-order velocity focusing when the optimal experimental parameters predicted using the coupled space and velocity focusing (CSVF) principle are used. The optimization model indicates that the delayed extraction technique is more effective in compensating for the initial ion velocity spread than reflectors. The calculation shows that for ions with m / z of 10,000, the predicted maximum mass resolving power ( R m ) can reach 750,000 using a single-stage R-TOF MS with an effective total length of about 2.4 m, or approximately 130,000 when accounting for the temporal response limit of ion detectors. The calculation model also reveals that in second-order focusing conditions, ions have two focusing points along the flight path, instead of just one at the detector as conventionally believed. The result indicates that the new model is critically important for the advancement of R-TOF MS.

Source: Journal of the American Society for Mass Spectrometry

DOI: 10.1021/jasms.5c00167

Authors: Yi-Hong Cai, Yi-Sheng Wang

Institutions: Genomics Research Center, Academia Sinica, Academia Sinica

Language: English

Topic: Mass Spectrometry Techniques and Applications

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Academia Sinica, Ministry of Science and Technology, Taiwan