Quality control for building libraries from electrospray ionization tandem mass spectra

Area of Science:

• Analytical Chemistry
• Spectroscopy

Background:

• Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS(2)) is vital for analyzing complex mixtures.
• Unlike gas chromatography/mass spectrometry (GC/MS), ESI MS(2) spectra present unique challenges for library matching due to variable precursor ions and acquisition parameters.

Purpose of the Study:

• To develop and present robust procedures for creating a high-quality tandem mass spectral library for electrospray ionization.
• To address the challenges associated with ESI MS(2) spectral variability and noise for accurate compound identification.

Main Methods:

• Acquiring MS(2) spectra for all major MS(1) peaks in infusion runs.
• Clustering MS(2) spectra and generating consensus spectra, incorporating intensity-based constraints and peak testing for noise reduction.
• Human evaluation of consensus spectra based on peak annotation and consistency across different energies.

Main Results:

• Developed and implemented procedures for building a comprehensive ESI MS(2) spectral library.
• Successfully created a library from over 9000 compounds, generating approximately 230,000 spectra.
• The developed methods effectively address spectral variability and noise, yielding high-quality reference spectra.

Conclusions:

• The presented procedures enable the creation of a valuable ESI MS(2) spectral library.
• This library significantly aids in the accurate identification and quantification of compounds in complex samples.
• The methodology offers a standardized approach for building ESI MS(2) spectral libraries for routine analysis.