Ion Fragmentation and Filtering by Alpha Function in Ion Mobility Spectrometry for Improved Compound Differentiation

Area of Science:

• Analytical Chemistry
• Spectrometry
• Ion Mobility Spectrometry

Background:

• Collision induced dissociation (CID) is crucial in mass spectrometry for ion structural analysis and compound identification beyond mass-to-charge ratio (m/z).
• CID involves increasing ion kinetic energy, leading to fragmentation upon collision with neutral molecules if sufficient energy is applied.

Purpose of the Study:

• To demonstrate collision induced dissociation (CID) for the first time in a field asymmetric ion mobility spectrometer (FAT-IMS).
• To analyze the effect of operational parameters on fragmentation efficiency within the FAT-IMS.
• To introduce a method for prefiltering analytes using the alpha function to mitigate spectral interferences.

Main Methods:

• Implementation and testing of CID within a field asymmetric time of flight ion mobility spectrometer (FAT-IMS) operating at ambient pressure and temperature.
• Separation of ions prior to dissociation in the FAT region to improve fragment ion assignment to precursor ions.
• Analysis of operational parameters influencing fragmentation efficiency and application of the alpha function for analyte prefiltering.

Main Results:

• Successful demonstration of CID in FAT-IMS, enabling ion separation before dissociation for enhanced fragment ion attribution.
• Investigation of eight saturated alcohols revealed substance-specific fragmentation patterns, offering orthogonal information for analyte identification.
• Introduction of a prefiltering method using the alpha function effectively reduced spectral interferences.

Conclusions:

• FAT-IMS is a viable platform for implementing CID, offering advantages such as ambient operation and pre-dissociation ion separation.
• CID in FAT-IMS provides valuable substance-specific fragmentation data, augmenting analyte characterization.
• The developed prefiltering method enhances spectral quality by removing interferences.