Table 3. Analysis of MS1 Isotopic Masses and Abundances Obtained from the LC-QTOF ESI + and ESI– Modes.
| obs. m/z (Da) | exact m/z (Da) | mass err. (ppm) | obs. abundance (%) | predicted abundance (%) | abundance diff. (%) | |
|---|---|---|---|---|---|---|
| PBNA, [M + H]+ | 220.1118 | 220.1121 | –1.36 | 100.00 | 100.00 | 0.00 |
| 221.1154 | 221.1153 | 0.45 | 17.86 | 17.83 | 0.03 | |
| 222.1185 | 222.1186 | –0.45 | 1.43 | 1.50 | –0.07 | |
| PBNA-NO2, [M – H]− | 263.0825 | 263.0826 | –0.38 | 100.00 | 100.00 | 0.00 |
| 264.0850 | 264.0857 | –2.65 | 18.18 | 18.24 | –0.06 | |
| 265.0885 | 265.0884 | 0.38 | 2.05 | 1.98 | 0.07 | |
| PBNA-(NO2)2 [M – H]− | 308.0674 | 308.0677 | –0.97 | 100.00 | 100.00 | 0.00 |
| 309.0705 | 309.0707 | –0.65 | 19.05 | 18.67 | 0.38 | |
| 310.0728 | 310.0731 | –0.97 | 2.38 | 2.47 | –0.09 | |
| PBNA-(NO2)3, [M – H]− | 353.0531 | 353.0528 | 0.85 | 100.00 | 100.00 | 0.00 |
| 354.0562 | 354.0557 | 1.41 | 17.74 | 19.10 | –1.36 | |
| 355.0582 | 355.0579 | 0.84 | 2.90 | 2.96 | –0.06 | |
| PBNA-(NO2)4, [M – H]− | 398.0376 | 398.0378 | –0.50 | 100.00 | 100.00 | 0.00 |
| 399.0404 | 399.0406 | –0.50 | 19.50 | 19.53 | –0.03 | |
| 400.0440 | 400.0428 | 3.00 | 3.00 | 3.45 | –0.45 | |
| PBNA-(NO2)5, [M – H]− | 443.0230 | 443.0229 | 0.23 | 100.00 | 100.00 | 0.00 |
| 444.0273 | 444.0256 | 3.83 | 20.00 | 19.96 | 0.04 | |
| 445.0284 | 445.0277 | 1.57 | 4.00 | 3.95 | 0.05 |