Citation:

Fan, T. W., R. M. Higashi, AND A. N. Lane. CHEMICAL CHARACTERIZATION OF A CHELATOR-TREATED SOIL HUMATE BY SOLUTION-STATE MULTINUCLEAR TWO-DIMENSIONAL NMR WITH FTIR AND PYROLYSIS-GCMS. (R825960). ENVIRONMENTAL SCIENCE & TECHNOLOGY. Oxford Journals, 34:1636-1646, (2000).

Description:

A California forest soil used for contaminant bioavailability
studies was extracted for humic substances (HS) and
then treated with 4,5-dihydroxy-1,3-benzene disulfonate
("Tiron") to remove exchangeable metal ions. This yielded
HS that was readily water-soluble at neutral pH without
residual Tiron contamination, and the gel electrophoretic
pattern was very similar to an international reference HS.
The improved solubility facilitated analysis of HS by solution-state 1-D and 2-D ¹H, ¹³C, ³¹P, and ¹³C-¹H NMR. The
amino acids Gly, Ala, Leu, Ile, Val, Asp, Ser, Thr, Glu, and
Pro were identified in intact HS as peptidic from scalar
coupling in TOCSY and dipolar interactions in NOESY and
then confirmed by acid digestion of HS with 2-D ¹H
NMR and GCMS analysis. The presence of peptides was
also corroborated by FT-IR and pyrolysis-GCMS results.
Carbohydrates containing - and -pyranoses, methoxy-
phenylpropanyl structures, phosphate mono/diesters,
polyphosphates, plus phosphatidic acid esters were also
evident. Furthermore, the ¹H NOESY, TOCSY, and HSQC
together indicated that the peptidic side chains were mobile,
whereas aromatic groups were relatively rigid. Thus the
peptidic moieties may be more readily accessible to aqueous
contaminants than aromatic groups.

Record Details:

Record Type:DOCUMENT( JOURNAL/ PEER REVIEWED JOURNAL)

Product Published Date:01/01/2000

Record Last Revised:12/22/2005

Record ID: 77380

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Document IDs:

EPA Number :R825960