posted on 2024-02-23, 13:33authored byQiong Pan, Chen He, Quan Shi
Inaccuracies
in ion detection and signal processing can undermine
confidence in the molecular formula assignment of high-resolution
mass spectrometry, which relies on precise matching of the mass-to-charge
ratio (m/z). This study proposes
a novel graph-based spectra calibration method, MSCMcalib, which implements
coordinate transformation and pattern detection. MSCMcalib maps uncalibrated m/z data onto a modified 2D mass defect
plot, facilitating the automatic calibration of detected lines, i.e.,
the calibration of uncalibrated peaks aligned with these lines. The
“propagation” method is subsequently employed to accurately
and automatically calibrate 605 m/z values across multiple lines, encompassing 98% of the m/z range. The calibrated m/z values divide the m/z range of the spectrum into multiple subintervals, with each subinterval
undergoing a process of “scaling” calibration. The utilization
of narrower partitions effectively mitigates divergence issues at
both ends that arise from the polynomial fitting of errors against m/z. The effectiveness of MSCMcalib is
validated through the calibration of SRFA data with m/z error ranges spanning from −10 to −6
ppm, resulting in an additional assignment of 11%–30% more
molecular formulas compared to the quadratic fitting calibration.