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

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Spectrometry

Background:

• Conventional reflectron time-of-flight mass spectrometry (R-TOF MS) relies on multistage reflectors for second-order velocity focusing.
• This assumption limits the optimization and efficiency of R-TOF MS instruments.

Purpose of the Study:

• To investigate the fundamental principles governing reflectron time-of-flight mass spectrometry.
• To demonstrate the potential of single-stage reflectors for achieving second-order velocity focusing.
• To challenge existing models of ion trajectory and focusing in R-TOF MS.

Main Methods:

• Application of the coupled space and velocity focusing (CSVF) principle for optimization.
• Development of a calculation model for ion trajectory and focusing.
• Analysis of ion focusing points under second-order focusing conditions.

Main Results:

• A single-stage reflector can achieve second-order velocity focusing with optimal parameters predicted by the CSVF principle.
• Delayed extraction is more effective than reflectors in managing initial ion velocity spread.
• Predicted mass resolving power (Rm) can reach 750,000 for m/z 10,000 ions.
• Ions exhibit two focusing points in second-order focusing conditions, contrary to prior beliefs.

Conclusions:

• The study presents a new model critical for advancing reflectron time-of-flight mass spectrometry.
• Single-stage reflectors, when optimized, offer a viable alternative to multistage designs.
• Revising the understanding of ion focusing is essential for future R-TOF MS development.