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Phosphorus K-edge XANES spectroscopy has probably often underestimated iron oxyhydroxide-bound P in soils.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Prietzel, Jörg Klysubun, Wantana |
| Copyright Year | 2018 |
| Abstract | Phosphorus (P) K-edge X-ray absorption near-edge structure (XANES) spectra of orthophosphate (oPO4) bound to soil FeIII minerals (e.g. ferrihydrite, goethite) show a pre-edge signal at 2148-2152 eV. It is unknown whether organic P bound to FeIII oxyhydroxides also show this feature. Otherwise, Fe-bound soil P may be underestimated by P K-edge XANES spectroscopy, because a large portion of Fe oxyhydroxide-bound P in soils is organic P. K-edge XANES spectra were obtained for different organic P compounds present in soils [inositol hexaphosphate (IHP), glucose-6-phosphate (G6P), adenosine triphosphate (ATP)] after sorption to ferrihydrite or goethite and compared with spectra of oPO4 adsorbed to these minerals. P sorption to ferrihydrite increased in the sequence IHP ≪ G6P < oPO4 < ATP. P sorption to goethite increased in the sequence G6P < oPO4 ≪ ATP = IHP. Pre-edge signals in P K-edge XANES spectra of organic P adsorbed to Fe oxyhydroxides were markedly smaller compared with those of oPO4 adsorbed to these minerals and absent for FeIII oxyhydroxide-bound ATP as well as goethite-bound IHP. Linear combination fitting (LCF) performed on spectra of IHP, G6P or ATP adsorbed to ferrihydrite or goethite, using only spectra of FeIII oxyhydroxide-bound oPO4 as reference compounds for Fe-bound P, erroneously assigned >93% (ferrihydrite) or >41% (goethite) of Fe-bound P to non-Fe-bound P species. Inclusion of FeIII oxyhydroxide-bound IHP as reference compounds markedly increased the recovery of oxyhydroxide-bound organic P. Thus, Fe-bound soil P has probably often been underestimated by LCF in soil XANES studies where IHP adsorbed to ferrihydrite and to goethite were not included as reference compounds. |
| Starting Page | 1736 |
| Ending Page | 1744 |
| Page Count | 9 |
| File Format | PDF HTM / HTML |
| DOI | 10.1107/S1600577518013334 |
| PubMed reference number | 30407184 |
| Journal | Medline |
| Volume Number | 25 |
| Part | 6 |
| Alternate Webpage(s) | http://journals.iucr.org/s/issues/2018/06/00/hf5935/hf5935.pdf |
| Alternate Webpage(s) | https://doi.org/10.1107/S1600577518013334 |
| Journal | Journal of synchrotron radiation |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
