Lower limit of detection achieved by raw band-target entropy minimization (rBTEM) for trace and coeluted gas chromatography-mass spectrometry components

Full-scan gas chromatography-mass spectrometry (GC-MS) provides rapid untargeted screening and detection for trace and coeluting components. Even though modern mass spectrometers have sufficient sensitivity to detect signals of trace components, this does not translate to the ability of the data-processing approach to isolate interference signals and extract pure component spectra. The raw band-target entropy minimization (rBTEM) approach based on band-target entropy minimization was previously reported to enable accurate spectra reconstruction from severely coeluting and trace GC-MS components. In this study, we evaluate the limit of detection for the approach. This study is systematically compared to classical spectral deconvolution for measurements of chlorpyrifos pesticide standards sampled with solid-phase microextraction at various concentration levels in both distilled and seawater media. The rBTEM approach was able to detect chlorpyrifos at 0.5 ppb in distilled water and 1.0 ppb in seawater while the classical approach provided numerous false negative results. In addition, rBTEM consistently provided higher match scores for chlorpyrifos. Attaining accurate identification of trace and coeluting components from full-scan GC-MS analysis has immense potential impact in biomedical, agricultural, and environmental work.