TABLE 1.
Summary of biomarker candidates identified by random forests analysis
| Identity | m/z | Retention time | Empirical formula | Mass error | Mean rank (95% CI) |
|---|---|---|---|---|---|
| min | ppm | ||||
| Top biomarker candidates (and adducts) | |||||
| Kynurenic acid | 190.0510+ | 2.78 | C10H7NO3 | 3.2 | 2.0 (1.56–2.52) |
| Pipecolic acid | 130.0873+ | 0.37 | C6H11NO2 | 3.8 | 2.3 (1.96–2.72) |
| Glycine betainea | |||||
| a | 140.0691+ | 0.32 | C5H11NO2Na | 2.9 | 2.4 (2.04–2.64) |
| b | 118.0858+ | 0.36 | C5H11NO2 | 8.5 | 5.6 (5.24–6.08) |
| c | 156.0434+ | 0.31 | C5H11NO2K | 4.5 | 7.2 (6.48–7.84) |
| Glucose | |||||
| d | 215.0351− | 0.34 | C6H12O6Cl | 13.5 | 3.3 (2.88–3.64) |
| Other notable biomarker candidates | |||||
| Citric acid | |||||
| a | 215.0166+ | 0.65 | C6H8O7Na | 0.9 | 42.8 (36.68–48.8) |
a Where a = [Na+] adduct; b = [H+] protonated molecular ion; c = [K+] adduct, and d = [Cl−] adduct.