Table 1.
Limit of detection (LOD, on column injected standards) for metabolites analyzed in targeted metabolites approach. For LC-MS/MS, metabolites were determined by HILIC-MS/MS except for Acyl-CoAs which were determined by RPLC-MS/MS.
| Metabolites | LOD (pmol) GC × GC-TOFMS | LOD (pmol) LC-MS/MS | Metabolites | LOD (pmol) GC × GC-TOFMS | LOD (pmol) LC-MS/MS |
|---|---|---|---|---|---|
| Amino acids | Mesaconic acid | 0.05 | 10 | ||
| Alanine | 0.03 | a | Methylsuccinic acid | 0.03 | 1 |
| Aspartic acid | 0.25 | a | Pyruvate | 0.015 | 7 |
| Cysteine | 0.25 | a | Phosphoenolpyruvate | 0.50 | 5 |
| Glutamic acid | 0.10 | a | Methylmalonic aicd | 0.05 | a |
| Glutamine | 0.25 | a | 2-Methylmalic acid | 0.04 | a |
| Glycine | 0.003 | 7.5 | Oxalic acid | 0.03 | a |
| Isoleucine | 0.02 | a | Glyceric acid | 0.03 | a |
| Leucine | 0.03 | a | Nucleotides | ||
| Phenylalanine | 0.25 | a | AMP | b | 1 |
| Proline | 0.05 | a | ADP | b | 2 |
| Serine | 0.05 | 2 | ATP | b | 2 |
| Threonine | 0.05 | a | NAD | b | 0.5 |
| Tyrosine | 0.10 | a | NADP | b | 0.5 |
| Valine | 0.025 | a | NADH | b | 2 |
| Carboxylic acids | NADPH | b | 4 | ||
| 3-Hydroxybutyric acid | 0.025 | 3.5 | Small peptides | ||
| α-Ketoglutaric acid | 0.075 | a | Glutathione oxidized | b | 1 |
| Citric acid | 0.075 | a | Glutathione reduced | b | c |
| Fumaric acid | 0.05 | 3 | Acyl-CoAs | ||
| Succinic acid | 0.05 | a | Acetyl-CoA | b | 2 |
| Malic acid | 0.05 | 0.5 | Butyryl-CoA | b | 1 |
| Glycolic acid | 0.005 | a | Hydroxybutyryl-CoA | b | 2 |
| Glyoxylic acid | 0.05 | a | Propionyl-CoA | b | 0.5 |
| Ethylmalonic acid | 0.05 | 1.5 | Succinyl-CoA | b | 0.5 |
a
: not applied to LC-MS/MS
b
: not applied to GC × GC-TOF-MS
c
: the analyte is not sufficiently stable to measure