Improved segmented-scan spectral stitching for stable isotope resolved metabolomics (SIRM) by ultra-high-resolution Fourier transform mass spectrometry

• Published in: Analytica chimica acta 2019-11, Vol.1080, p.104-115
• Main Authors: Kang, Woo-Young, Thompson, Patrick T., El-Amouri, Salim S., Fan, Teresa W.M., Lane, Andrew N., Higashi, Richard M.
• Format: Article
• Language: English
• Subjects: Carbon Isotopes - chemistry; Fourier Analysis; Glucose - chemistry; Glucose - metabolism; Humans; Isotope Labeling; Lipids - analysis; Macrophages - chemistry; Macrophages - metabolism; Mass Spectrometry - methods; Metabolomics - methods; Spectral binning; Spectral stitching; Spheroids, Cellular - chemistry; Spheroids, Cellular - metabolism; Stable isotope-resolved metabolomics (SIRM); Ultra-high-resolution Fourier transform mass spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2019.06.019

We have implemented a linear ion trap (LIT)-based SIM-stitching method for ultra-high-resolution Fourier transform mass spectrometry (FTMS) that increases the S/N over a wide m/z range compared to non-segmented wide full-scan (WFS) spectra. Here we described an improved segmented spectral scan stitching method that was based on quadrupole mass filter (QMF)-SIM, which overcame previous limitations of ion signal loss in LIT. This allowed for accurate representation of isotopologue distributions, both at natural abundance and in stable isotope-resolved metabolomics (SIRM)-based experiments. We also introduced a new spectral binning method that provided more precise and resolution-independent bins for irreversibly noise-suppressed FTMS spectra. We demonstrated a substantial improvement in S/N and sensitivity (typically > 10-fold) for 13C labeled lipid extracts of human macrophages grown as three-dimensional (3D) cell culture, with detection of an increased number of 13C isotopologue ions. The method also enabled analysis of extracts from very limited biological samples. [Display omitted] •Sample-specific segments were designed for the improved spectral stitching method.•Use of quadrupole mass filter-selected ion monitoring eliminates edge effect.•Binary floating point-based binning creates precise and resolution-independent bins.•Method was used on carbon-13 incorporated lipid profiling of human macrophage samples.•Method provides higher sensitivity and dynamic range compared with wide full-scan.