Table 5.
Chemical shift assignments of characteristics signals in 1H NMR spectroscopy of some metabolites in the repeated cooking oils.
| No. | Functional group | Compound | Chemical shift (δH)/splitting pattern |
|---|---|---|---|
| FA | |||
| 1. | Acyl group-omega 6 | CH3 | 0.89 (t, J = 6.8 Hz) |
| 2. | Acyl group | CH2(n) | 1.27 (m) |
| 3. | Acyl group | -OCO–CH2–CH2- | 1.61 (m) |
| 4. | Acyl group-omega 9 | -CH2–CH CH– | 1.99 (m) |
| 5. | Unsaturated fatty acids | -CH2CH CH | 2.03 (m) |
| 2.07 (m) | |||
| 6. | Acyl group | –OCO–CH2–CH2– | 2.33 (m) |
| PUFA | |||
| 7. | Acyl group – linoleic, linolenic acid | = CHCH2CH = | 2.77 (t, J = 6.4 Hz) |
| 8. | Acyl group – linoleic, linolenic acid | -CH CH- | 5.36 (m) |
| TG | |||
| 9. | TG | CH2-α (–CH2–OCO–) | 4.15 (q, J = 5.6 Hz) |
| 10. | TG | CH2-α′ (1′a,b-CH2–OCO–) | 4.31 (dd, J = 4.4, 12.0 Hz) |
| 11. | TG | CH-β (2′-CHOCO–) | 5.28 (m) |
| 12. | GE | 4.47 (dd, J = 4.0, 11.6 Hz), 3.98 (dd, J = 5.6, 12.0 Hz), 2.91 (t, J = 6.0 Hz), 2.70 (m), 2.36 (m) | |
| 13. | 3-MCPD | 3.72 (d, J = 4.8 Hz), 2.36 (m) | |
δH in ppm. Splitting pattern: doublet (d), triplet (t), multiplet (m), doublet of doublets (dd), quartet (q).