Figure 2.

Result of NMF-based deconvolution (number of rank: 5, algorithm: Frobenius, and initialization: NNDSVD) of the chromatographic peaks including 2,6-dimethylphenol (12.8 μg mL^–1). (a) Total ion chromatogram. (b) Deconvoluted chromatogram. (c) Original spectrum. (d) Deconvoluted spectrum of rank 1: The component of the spectrum is originated from the road dust sample. It is assumed to be 2-tridecanol from the match factor and 2-decanol from the match factor with the retention index. (e) Deconvoluted spectrum of rank 2: The component of the spectrum is the spiked compound 2,6-dimethylphenol. It is successfully assigned through a library search.