Session: Parallel session 6 - Instrumental development

From Rough Signal to Polished Spectrum: Absorption Mode Two-dimensional Mass Spectrometry

Objectives

Two-dimensional mass spectrometry (2D MS) is a tandem mass spectrometry method where precursor and fragment ions are correlated without isolation [1]. For narrowband 2D mass spectra with limited precursor m/z ranges, phase-corrected absorption mode improves resolving power and signal-to-noise ratios [2]. This study seeks to extract analytical information from all 2D mass spectra with maximum signal-to-noise ratio and resolving power by expanding phase-corrected absorption mode to broadband 2D MS.

Methods

2D mass spectra of diverse samples (intact proteins, peptide isoform mixtures, protein digests, plant extracts) were recorded on FT-ICR mass spectrometers with magnetic fields between 7-15 T (Bruker Daltonics, Germany) [1]. All data processing and visualization was performed with the open-source Spectrometry Processing Innovative Kernel (SPIKE) software, developed in 64-bit python language [3].

Results

Phase progression in 2D mass spectra is linear with frequency in the vertical precursor ion dimension and quadratic in the horizontal fragment dimension [4]. For accurate phase correction, different parameters need to be optimized. Data processing for absorption mode is performed in batch processing to eliminate caps on dataset size imposed by available RAM. We performed phase correction for 2D mass spectra with a precursor range of m/z 808-3000 [5].

Conclusion

Phase-corrected absorption mode 2D mass spectra show that both signal-to-noise ratio and resolving power can be doubled compared to magnitude mode. We compare the results of data analysis for broadband 2D mass spectra processed in absorption mode and magnitude mode to show how absorption mode 2D mass spectrometry improves confidence in peak assignments and relative quantification.

[1] https://doi.org/10.1007/s00249-019-01348-5

[2] https://doi.org/10.1021/jasms.2c00319

[3] https://arxiv.org/abs/1608.06777

[4] https://doi.org/10.3390/molecules26113388

[5] https://doi.org/10.1021/acs.analchem.3c02225