High-Resolution Characterization of Organic Phosphorus in Soil Extracts Using 2D H-1-P-31 NMR Correlation Spectroscopy

Summary, in English

Organic phosphorus (P) compounds represent a major component of soil P in many soils and are key sources of P for microbes and plants. Solution NMR (nuclear magnetic resonance spectroscopy) is a powerful technique for characterizing organic P species. However, P-31 NMR spectra are often complicated by overlapping peaks, which hampers identification and quantification of the numerous P species present in soils. Overlap is often exacerbated by the presence of paramagnetic metal ions, even if they are in complexes with EDTA following NaOH/EDTA extraction. By removing paramagnetic impurities using a new precipitation protocol, we achieved a dramatic improvement in spectral resolution. Furthermore, the obtained reduction in line widths enabled the use of multidimensional NMR methods to resolve overlapping P-31 signals. Using the new protocol on samples from two boreal humus soils with different Fe contents, 2D H-1-P-31 correlation spectra allowed unambiguous identification of a large number of P species based on their P-31 and H-1 chemical shifts and their characteristic coupling patterns, which would not have been possible using previous protocols. This approach can be used to identify organic P species in samples from both terrestrial and aquatic environments increasing our understanding of organic P biogeochemistry.

• Author: Johan Vestergren; Andrea G. Vincent; Mats Jansson; Per Persson; Ulrik Istedt; Gerhard Groebner; Reiner Giesler; Juergen Schleucher
• Publishing year: 2012
• Language: English
• Pages: 3950-3956
• Publication/Series: Environmental Science & Technology
• Volume: 46
• Links: http://dx.doi.org/10.1021/es204016h
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Earth and Related Environmental Sciences
• Status: Published
• ISBN/ISSN/Other: ISSN: 1520-5851