Table 1.
Optimized MS/MS conditions for oxFA detection and quantification.
| Fatty Acid Species | Molecular Ion | Molecular Ion m/z | DP (eV) | Quantitative Transition | Quantitative Transition CE (eV) | Qualitative Transition | Qualitative Transition CE (eV) | CXP (eV) | QIR | QIR Range (75–125%) |
|---|---|---|---|---|---|---|---|---|---|---|
| LA | [M + Na]+ | 303.3 | 46 | 303.3 → 303.3 | 10 | 303.3 → 303.3 | 16 | 14 | 2.09 | 1.56–2.61 |
| AA | [M + Na]+ | 327.3 | 36 | 327.3 → 327.3 | 13 | 327.3 → 327.3 | 17 | 6 | 1.97 | 1.47–2.46 |
| HPODE | [M + Na]+ | 335.3 | 70 | 335.3 → 335.3 | 10 | 335.3 → 335.3 | 19 | 14 | 1.96 | 1.47–2.45 |
| HODE | [M + Na]+ | 319.3 | 76 | 319.3 → 319.3 | 13 | 319.3 → 319.3 | 18 | 8 | 1.96 | 1.47–2.45 |
| KODE | [M + Na]+ | 317.3 | 81 | 317.3 → 317.3 | 13 | 317.3 → 317.3 | 22 | 10 | 1.91 | 1.43–2.39 |
| HPETE | [M + Na]+ | 359.3 | 46 | 359.3 → 359.3 | 7 | 359.3 → 359.3 | 14 | 14 | 1.72 | 1.29–2.15 |
| HETE | [M + Na]+ | 343.3 | 56 | 343.3 → 343.3 | 13 | 343.3 → 343.3 | 16 | 10 | 2.18 | 1.63–2.73 |
| KETE | [M + Na]+ | 341.3 | 71 | 341.3 → 341.3 | 13 | 341.3 → 341.3 | 20 | 12 | 1.94 | 1.45–2.43 |
| C17:0 | [M + Na]+ | 293.5 | 51 | 293.5 → 293.5 | 7 | 293.5 → 293.5 | 13 | 10 | 1.68 | 1.26–2.10 |
MS/MS conditions were optimized for detection of the single sodium adduct of each analyte; specifically declustering potential (DP), quantitative transition collision energy (CE), qualitative transition CE, and collision exit potential (CXP). Values are listed in electrovolts (eV). The listed qualifier ion ratio (QIR) is based on the noted pseudo-molecular transitions measured using the listed optimized MS/MS conditions in combination with the HPLC method outlined in the text. Based on the intensity of the qualitative transition chosen and accepted standards for QIR variation (75–125%), the tolerable range in QIR for each species was calculated.