Version 2 2021-09-02, 14:07Version 2 2021-09-02, 14:07
Version 1 2021-08-30, 16:33Version 1 2021-08-30, 16:33
journal contribution
posted on 2021-09-02, 14:07authored byDanning Huang, Marcos Bouza, David A. Gaul, Franklin E. Leach, I. Jonathan Amster, Frank C. Schroeder, Arthur S. Edison, Facundo M. Fernández
Fourier
transform ion cyclotron resonance (FT-ICR) and Orbitrap
mass spectrometry (MS) are among the highest-performing analytical
platforms used in metabolomics. Non-targeted metabolomics experiments,
however, yield extremely complex datasets that make metabolite annotation
very challenging and sometimes impossible. The high-resolution accurate
mass measurements of the leading MS platforms greatly facilitate this
process by reducing mass errors and spectral overlaps. When high resolution
is combined with relative isotopic abundance (RIA) measurements, heuristic
rules, and constraints during searches, the number of candidate elemental
formula(s) can be significantly reduced. Here, we evaluate the performance
of Orbitrap ID-X and 12T solariX FT-ICR mass spectrometers in terms
of mass accuracy and RIA measurements and how these factors affect
the assignment of the correct elemental formulas in the metabolite
annotation pipeline. Quality of the mass measurements was evaluated
under various experimental conditions (resolution: 120, 240, 500 K;
automatic gain control: 5 × 104, 1 × 105, 5 × 105) for the Orbitrap MS platform. High average
mass accuracy (<1 ppm for UPLC-Orbitrap MS and <0.2 ppm for
direct infusion FT-ICR MS) was achieved and allowed the assignment
of correct elemental formulas for over 90% (m/z 75–466) of the 104 investigated metabolites. 13C1 and 18O1 RIA measurements
further improved annotation certainty by reducing the number of candidates.
Overall, our study provides a systematic evaluation for two leading
Fourier transform (FT)-based MS platforms utilized in metabolite annotation
and provides the basis for applying these, individually or in combination,
to metabolomics studies of biological systems.