Absorption mode Fourier transform electrostatic linear ion trap mass spectrometry

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Physical Chemistry

Background:

• Absorption mode spectra offer advantages over magnitude mode in Fourier transform mass spectrometry (FTMS).
• Generating absorption spectra requires precise phase determination at data acquisition onset, a significant challenge.
• The phasing problem is notably simpler for electrostatic traps compared to Fourier transform ion cyclotron resonance (FTICR) instruments.

Purpose of the Study:

• To present a straightforward method for generating absorption spectra from Fourier transform electrostatic linear ion trap mass spectrometers.
• To simplify the process of obtaining absorption spectra by addressing the phase determination issue.

Main Methods:

• A time-shifting technique is applied to data before Fourier transformation.
• This synchronization aligns data acquisition onset with ion acceleration into the electrostatic trap.
• This ensures an initial phase of zero for all frequencies.

Main Results:

• The absorption mode demonstrated a 1.7-fold increase in spectral resolution (full width at half maximum, fwhm).
• Reduced peak tailing was observed in the absorption spectra.
• Methodology for processing unsynchronized data to determine necessary time shifts was also discussed.

Conclusions:

• The proposed time-shifting method effectively generates absorption spectra from electrostatic traps.
• This approach significantly improves spectral resolution and peak shape.
• It offers a practical solution to the long-standing phasing problem in FTMS.