Research Article
Molecular Signatures of Humic Acids from Different Sources as Revealed by Ultrahigh Resolution Mass Spectrometry
Table 2
Number of peaks assigned to molecular formulas having similar elemental composition to each compound group and the sum of their peak magnitudes.
| | Sample name | JFHA | SRHA | LEHA |
| | Number of formulas | 2246 | 3559 | 4398 | | Number of formulas similar to fatty acids and sulfonic acids | 122 (5) | 41 (1)a | 34 (1) | | Carbohydrates | 0 (0) | 0 (0) | 0 (0) | | Unsaturated aliphatic compounds containing N | 0 (0) | 1 (0) | 0 (0) | | Unsaturated aliphatic compounds | 683 (30) | 277 (8) | 312 (7) | | Highly unsaturated compounds | 573 (26) | 1828 (51) | 1273 (29) | | Highly aromatic compounds | 331 (15) | 788 (22) | 937 (21) | | Polycyclic aromatics | 537 (24) | 624 (18) | 1842 (42) | | Sum of peak magnitudes assigned to fatty acids and sulfonic acids (×106) | 19052 (25) | 2394 (4) | 1120 (2) | | Carbohydrates (×106) | 0 (0) | 0 (0) | 0 (0) | | Unsaturated aliphatic compounds containing N (×106) | 0 (0) | 3 (0) | 0 (0) | | Unsaturated aliphatic compounds (×106) | 38187 (50) | 6524 (11) | 3681 (6) | | Highly unsaturated compounds (×106) | 6717 (9) | 31135 (54) | 13678 (22) | | Highly aromatic compounds (×106) | 4374 (6) | 11535 (20) | 12110 (20) | | Polycyclic aromatics (×106) | 7517 (10) | 6600 (11) | 30308 (50) | | Sum (×106) | 75847 | 58191 | 60897 |
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aValues in parentheses are percentages of either the corresponding number of assigned formulas or the corresponding summed peak magnitudes.
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