Research Article
Molecular Signatures of Humic Acids from Different Sources as Revealed by Ultrahigh Resolution Mass Spectrometry
Table 1
Molecular parameters of (a) humic acids from Jiufeng forest soil, (b) humic acids from Suwannee River, and (c) humic acids from leonardite derived from assigned molecular formulasa.
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aIntensity weighted average values are displayed for number of carbons (Cwa), hydrogens (Hwa), oxygens (Owa), nitrogens (Nwa), sulfurs (Swa), molecular weights (m/zwa), hydrogen to carbon ratios (H/Cwa), and oxygen to carbon ratios (O/Cwa). b,cBoth MLBL% and CRAM% are obtained by dividing the total intensity of the corresponding molecular formula by the total intensity of the molecular formula. |