Table 5.
Assignment of –CHO functional groups of 1H NMR signals of aldehydic LOPs (secondary LOPs) present in the 1H NMR profiles of PDMS-treated sunflower oil, including chemical shift values, multiplicities, and their associated functional group assignments.
| Functional group | ||||
|---|---|---|---|---|
| Signal | δ-scale (ppm) | Multiplicity | Condensed function | Classification |
| a | 9.483–9.513 | d | –CHO | (E)-2-Alkenals |
| b | 9.513–9.541 | d | –CHO | (E,E)-2,4-Alkadienals |
| c | 9.541–9.563 | d | –CHO | 4,5-Epoxy-(E)-alkenals |
| d | 9.569–9.590 | d | –CHO | 4-Hydroxy-(E)-2-alkenals |
| e | 9.577–9.594 | d | –CHO | 4-Hydroperoxy-(E)-2-alkenals |
| f | 9.594–9.616 | d | –CHO | (Z,E)-2,4-Alkadienals |
| g | 9.741–9.762 | t | –CHO | n-Alkanals |
| h | 9.784–9.800 | t | –CHO | 4-Oxo-alkanals |
| i | 9.800–9.816 | t | –CHO | n-Alkanals of low-molecular-mass (ethanal, propanal and butanal) |
| j | 10.056–10.080 | d | –CHO | (Z)-2-Alkenals |
| k | 10.144–10.170 | d | –CHO | Unidentified unsaturated aldehyde |
d, doublet; t, triplet. Letter assignments of resonances correspond to those provided in Figure 5.