TABLE 1.
Metabolites with concentration gradients in CSF as identified from literature
| Metabolite | Reference | ID level | R 2 | β rel |
|---|---|---|---|---|
| 3,4‐Dihydroxyphenylacetic acid | 18 | 2 | 0.90 | 0.071 |
| 5‐Hydroxyindoleacetic acid | 18 , 19 , 20 | 1 | 0.97 | 0.109 |
| 5‐Hydroxytryptophol | 19 | 2 | 0.36 | −0.040 |
| Creatinine | 22 | 1 | 0.95 | 0.014 |
| γ‐Aminobutyric acid | 23 | 1 | 0.51 | −0.054 |
| Homocarnosine | 23 | 1 | 0.48 | 0.069 |
| Homovanillic acid | 18 , 20 | 1 | 0.96 | 0.125 |
| Hypoxanthine | 22 | 1 | 0.81 | 0.031 |
| 1‐Methylhistamine | 21 | 0 | NA | NA |
| Methylimidazoleacetic acid | 21 | 2 | 0.93 | 0.188 |
| Uric acid | 22 | 1 | 0.60 | −0.041 |
| Vanylglycol | 20 | 1 | 0.07 | −0.009 |
| Xanthine | 22 | 1 | 0.81 | 0.043 |
Note: The coefficient of determination (R 2) and the relative beta coefficient (β rel) were calculated using linear regression. Identification (ID) levels: 1 = identification based on m/z and RT of a reference compound, 2 = putative identification based on m/z only, 0 = not identified. NA = not available.