High sensitivity and broad dynamic range infrared multiphoton dissociation for a quadrupole ion trap

Area of Science:

• Analytical Chemistry
• Physical Chemistry

Background:

• Conventional infrared multiphoton dissociation (IRMPD) in quadrupole ion traps (QIT) suffers from low sensitivity due to conflicting pressure requirements for ion trapping and dissociation.
• Effective IRMPD requires low bath gas pressure (<1 mTorr), while optimal ion accumulation necessitates higher pressure (~20 mTorr).

Purpose of the Study:

• To develop a method for dynamic bath gas pressure control in QIT to enhance IRMPD sensitivity and dynamic range.
• To achieve both efficient ion trapping and effective IRMPD within a single experimental setup.

Main Methods:

• Implementing a dynamic pressure control system within the QIT.
• Switching bath gas pressure between ~20 mTorr for ion accumulation and <0.6 mTorr for IRMPD.
• Optimizing gas introduction to maintain constant trapping efficiency during accumulation.

Main Results:

• Achieved high sensitivity and broad dynamic range for IRMPD.
• Successfully combined maximum ion trapping efficiency with effective IRMPD.
• Demonstrated that optimized gas introduction maintains stable trapping efficiency, enabling broad dynamic range measurements.

Conclusions:

• Dynamic control of bath gas pressure is a viable strategy to overcome limitations in QIT-based IRMPD.
• This approach significantly improves the performance of IRMPD for sensitive and broad dynamic range analyses.
• The optimized method offers a pathway for more effective molecular analysis using QIT-IRMPD.