Table 3. Optimized conditions for selected-reaction mode tandem mass spectrometry analysis of fibrates and their metabolites.
| Function (min) | Retention time (min) | Compounda | Dwell time (s) | Precursor ion (m/z) | Product ion (m/z) | Cone voltage (V) | Collision energy (eV) |
|---|---|---|---|---|---|---|---|
| Negative-ion mode | |||||||
| 3.0–4.0 | 3.51 | CA | 0.05 | 213 | 126.7b | 20 | 14 |
| 84.7 | 16 | ||||||
| 4.5–5.5 | 5.03 | GF | 0.05 | 249 | 120.8b | 20 | 12 |
| 126.8 | 14 | ||||||
| Positive-ion mode | |||||||
| 3.0–4.0 | 3.66 | BF | 0.05 | 362 | 316b | 30 | 15 |
| 276 | 15 | ||||||
| 4.0–4.5 | 4.22 | FA | 0.05 | 319 | 233b | 24 | 18 |
| 139 | 30 | ||||||
| 5.0–5.5 | 5.19 | FF | 0.05 | 361 | 233b | 30 | 16 |
| 139 | 26 | ||||||
aCA, clofibric acid; GF, gemfibrozil; BF, bezafibrate; FA, fenofibric acid; FF, bProduct ion used for quantification.