Artifacts in four-sector tandem mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Proteomics

Background:

• Tandem mass spectrometry, specifically collision-induced dissociation (CID), is vital for peptide identification.
• Artifact peaks in CID spectra can complicate spectral interpretation and lead to inaccurate results.
• Understanding artifact origins is essential for reliable data analysis in proteomics.

Purpose of the Study:

• To identify and characterize artifacts present in 4-sector tandem CID mass spectra.
• To elucidate the origins of artifact peaks observed in peptide analysis.
• To improve the accuracy of spectral interpretation in mass spectrometry.

Main Methods:

• Analysis of protonated peptides produced by liquid secondary-ion mass spectrometry (LSIMS).
• Investigation of artifacts in 4-sector tandem CID mass spectrometry (MS1/MS2).
• Examination of decompositions in the second field-free region of an EBEB geometry machine.

Main Results:

• Two main types of artifacts were identified: matrix-related losses and co-isolated smaller peptides from chemical noise.
• Chemical noise ions from MS1 were shown to generate artifact peaks in MS2.
• Field-free region decompositions in MS2 were identified as a second artifact source, particularly with array detectors and floated collision cells.

Conclusions:

• Artifact peaks in CID mass spectra originate from both chemical noise and secondary reactions.
• Accurate interpretation of mass spectra requires a thorough understanding of artifact formation mechanisms.
• This knowledge is fundamental for both manual and automated spectral analysis of unknown compounds.