Enhancing signal and mitigating up-front peptide fragmentation using controlled clustering by gas-phase modifiers

Area of Science:

• Analytical Chemistry
• Biochemistry
• Physical Chemistry

Background:

• Up-front CID fragmentation complicates mass spectra analysis by causing premature ion breakdown.
• Existing methods to minimize fragmentation can reduce ion sensitivity.

Purpose of the Study:

• To introduce gas-phase modifiers to mitigate up-front CID fragmentation.
• To improve analytical sensitivity and reduce detection limits in mass spectrometry.

Main Methods:

• Utilized gas-phase modifiers (acetonitrile, acetone, cyclohexane, water, methanol) with curtain gas.
• Employed differential mobility spectrometry-mass spectrometry (DMS-MS) and precursor mass spectrum-scanning to monitor ion clustering.
• Tested the technique on BSA and mAb protein digests.

Main Results:

• Peptide ion-modifier clusters, particularly with acetonitrile and acetone, survived the atmosphere-to-vacuum interface.
• Up to 90% reduction in up-front CID fragmentation for fragile, highly charged peptides was achieved.
• Detection limits decreased by up to 82%, with a ~40% reduction in redundant spectra for protein digests.

Conclusions:

• Gas-phase modifiers effectively reduce up-front CID fragmentation and chemical noise.
• This technique enhances analytical sensitivity and accuracy in proteomics and peptidomics.
• The method offers a significant improvement for analyzing complex biological samples.