Analysis of Dataset 1 using MetaFIND. (a) Analysis of the reference feature 7.85 using MetaFIND. The features representing the hippurate signature (spectral regions 3.96–3.98 ppm, 7.54–7.56 ppm, 7.56–7.58 ppm, 7.84–7.86 ppm) are the first to appear above the x-axis.(b) Region 6.5–9.5 ppm enlarged. Features representing creatinine (spectral regions 3.05 ppm, 4.07 ppm) appear below the x-axis (anti-correlated). Feature 9.13 (nicotinic acid), omitted by PLS-DA feature selection, was uncovered using MetaFIND.