Multi-turn time-of-flight mass spectrometers with electrostatic sectors

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Instrument Development

Background:

• Mass resolution in time-of-flight (TOF) mass spectrometry is limited by flight path length.
• Achieving long flight paths within practical instrument sizes necessitates multi-turn or multi-passage ion optics.

Purpose of the Study:

• Investigate ion optics for multi-turn TOF mass spectrometers using electrostatic sectors.
• Introduce the concept of 'perfect' focusing conditions.
• Develop novel multi-turn TOF mass spectrometer designs.

Main Methods:

• Designed and developed the MULTUM Linear plus, a multi-turn TOF mass spectrometer with four cylindrical electric sectors and 28 quadrupole lenses.
• Developed the MULTUM II, an improved design utilizing four toroidal electric sectors to reduce complexity.
• Evaluated ion optical configurations and focusing conditions.

Main Results:

• Demonstrated that mass resolution increases with the number of ion cycles in multi-turn TOF systems.
• Achieved a mass resolution of 350,000 (m/z = 28, FWHM) with the MULTUM Linear plus after 501.5 cycles.
• The MULTUM II design simplifies the ion optical system compared to the MULTUM Linear plus.

Conclusions:

• Multi-turn TOF mass spectrometers with electrostatic sectors can achieve very high mass resolution.
• The number of ion cycles is a critical factor for enhancing mass resolution.
• The developed MULTUM series instruments offer advanced capabilities, including potential for tandem mass spectrometry.