Three metabolites, in three samples from each sample group that were statistically significant in differentiating between sample classes using pattern recognition modelling, were selected for confirmation using unprocessed chromatographic data. (A) OPLS-DA scores plot (tp vs tp) highlighting the three selected samples (S. Typhi: 45, S. Paratyphi A: 19, and control: 60). Panel B–D show one dimensional chromatographic peaks representing each metabolite from the three unprocessed plasma samples (coloured by sample group). Second dimension retention times (s) are shown along the x-axes and the peak intensities along the y-axes. (B) Phenylalanine (mass: 218, 1st retention time: 1785 s). (C) Pipecolic acid (mass: 156, 1st retention time: 1130 s). (D) 2-phenyl-2-hydroxybutanioc acid (mass: 193, 1st retention time: 1725 s). Panel E–M show the corresponding two dimensional chromatographic peaks with one peak for each sample and metabolite. First and second dimension retention times (s) are shown along the x and y-axes, respectively, and the peak area is shown along the z-axes. The peaks are coloured according to area (colour scale is shown to the right) and the top colour for the two lowest peaks for each metabolite is determined according to the colour scale of the highest peak for the same metabolite. (E, H, K) Phenylalanine for sample 45, 19, and 60, respectively. (F, I, L) Pipecolic acid for sample 19, 4, 5 and 60, respectively. (G, J, M) 2-phenyl-2-hydroxybutanioc acid for sample 45, 19, and 60, respectively.