Global Spectral Deconvolution Based on Non-Negative Matrix Factorization in GC × GC–HRTOFMS

A global spectral deconvolution,
based on non-negative matrix factorization
(NMF) in comprehensive two-dimensional gas chromatography high-resolution
time-of-flight mass spectrometry, was developed. We evaluated the
ability of various instrumental parameters and NMF settings to derive
high-performance detection in nontarget screening using a sediment
sample. To evaluate the performance of the process, a NIST library
search was used to identify the deconvoluted spectra. Differences
of the instrumental scan rates (25 and 50 Hz) in deconvolution were
evaluated and results show that a high scan rate enhanced the number
of compounds detected in the sediment sample. A higher mass resolution
in the range of 1 000 to 10 000 and a higher m/z precision in the deconvolution were
needed to obtain an accurate mass database. After removal of multiple
duplicate hits, which occurred in batch processes of NIST library
search on the deconvolution result, 62 unique assignable spectra with
a match factor ≥900 were obtained in the deconvoluted chromatogram
from the sediment sample, including 54 spectra that were refined by
the deconvolution. This method will help to detect and build up well-resolved
reference spectra from various complex mixtures and will accelerate
nontarget screening.