Mirror Switching for High-Resolution Ion Isolation in an Electrostatic Linear Ion Trap.

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Physical Chemistry

Background:

• Electrostatic linear ion trap mass spectrometers (ELIT) are used for ion manipulation.
• Previous methods utilized mirror switching for ion capture in ELIT devices.
• Spatial and temporal separation of ions within an ELIT is a known phenomenon.

Purpose of the Study:

• To develop and demonstrate a novel ion isolation technique in ELIT.
• To achieve high-resolution isolation of ions with similar mass-to-charge (m/z) ratios.
• To validate the effectiveness of selective mirror pulsing for ion purification.

Main Methods:

• Selective pulsing of entrance and exit ion mirrors in an ELIT.
• Utilizing spatial separation of ion packets for isolation.
• Employing multiple reflection-time-of-flight (MR-TOF) mass spectrometry for analysis.

Main Results:

• Successful isolation of protonated l-glutamine and l-lysine (Δ m/z = 0.0364).
• Isolation of isobaric phosphatidylcholine mixtures [PC P-18:0/22:6] and [PC 19:0/19:0] (Δ m/z = 0.0575).
• Achieved an isolation resolution greater than 35,000 fwhm in a 5.25 in. ELIT.

Conclusions:

• Selective mirror pulsing is an effective method for high-resolution ion isolation in ELIT.
• The technique allows for minimal loss of stored ions during isolation.
• Demonstrated resolution is sufficient to reduce contaminant overlap to less than 1% for equally abundant adjacent ions.