High-resolution quadrupole improves spectral purity and reduces interference from non-target ions in isobaric...

Area of Science:

• Proteomics
• Analytical Chemistry
• Biochemistry

Background:

• Mass spectrometry (MS)-based proteomics is vital for protein identification and quantification.
• Chimeric spectra, arising from multiple precursor fragmentations, compromise accuracy in peptide identification and isobaric mass tag (IMT) quantification.
• Existing solutions like computational deconvolution and ion mobility separation have limitations, leaving narrower isolation windows underexplored.

Purpose of the Study:

• To investigate the impact of narrower quadrupole isolation windows on spectral purity, identification accuracy, and quantification accuracy in MS-based proteomics.
• To assess the effectiveness of high-resolution isolation in mitigating interference from chimeric spectra.

Main Methods:

• Utilized a SCIEX TripleTOF instrument with a quadrupole optimized for precursor isolation at 0.1 Da (FWHH).
• Employed a three-proteome model (yeast, human, E. coli) with 8-plex iTRAQ labeling to evaluate interference effects.
• Compared results with standard-resolution quadrupole isolation (0.7 Da).

Main Results:

• High-resolution isolation (0.1 Da) significantly improved spectral purity and reduced quantification interference from non-target precursors.
• The strategy reduced false identifications caused by chimeric spectra.
• A trade-off was observed in sensitivity loss, suggesting potential synergy with other techniques like ion mobility.

Conclusions:

• High-resolution quadrupole isolation (0.1 Da) demonstrably enhances spectral purity and quantification accuracy compared to standard isolation (0.7 Da).
• This approach effectively minimizes false identifications stemming from chimeric spectra.
• The method shows significant promise for high-accuracy analyses in clinical proteomics.