Phosphorus-31 nuclear magnetic resonance spectral assignments of phosphorus compounds in soil NaOH-EDTA extracts

Asignaciones Espectrales de Fósforo de Resonancia Magnética Nuclear de Compuestos de Fósforo-31 en Extractos de Suelo de NaOH-EDTA

Turner, Benjamin L. and Mahieu, Nathalie and Condron, Leo M. (2003) Phosphorus-31 nuclear magnetic resonance spectral assignments of phosphorus compounds in soil NaOH-EDTA extracts. Soil Science Society of America Journal. 67:497-510.

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Abstract

Soil P composition can be conveniently determined in alkaline
extracts using solution 31P nuclear magnetic resonance (NMR) spectroscopy,
but spectral assignments are based on fragmentary literature
reports of model compounds in various extraction matrices. We report
solution 31P NMR chemical shifts of model P compounds, including inorganic
phosphates, orthophosphate monoesters and diesters, phosphonates,
and organic polyphosphates, determined in a standardized soil
P extractant (0.25 M NaOH and 0.05 M EDTA). Signals from nucleic
acids (DNA –0.37 ppm, RNA 0.54 ppm) and phospholipids (phosphatidyl
choline 0.78 ppm, phosphatidyl serine 1.57 ppm, phosphatidyl ethanolamine
1.75 ppm) could be differentiated in the orthophosphate diester
region, and were identified in a sample of cultured soil bacteria. Inorganic
and organic polyphosphates could be differentiated by the presence
of a signal at –9 ppm from the a phosphate of organic polyphosphates.
Some orthophosphate diesters, notably RNA and phosphatidyl
choline, degraded rapidly to orthophosphate monoesters in NaOH-EDTA
although DNA, other phospholipids, and orthophosphate monoesters
were more stable. Changes in probe temperature had a marked
influence on signal intensities and the relative magnitude of signals
from orthophosphate monoesters and inorganic orthophosphate, and
we suggest that solution 31P NMR spectroscopy of soil extracts be
performed at 20°C.

Item Type:	Article
NWISRL Publication Number:	1095
Subjects:	Soil > Chemistry > Phosphorous Research methodology Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:50
Last Modified:	09 Nov 2016 17:46
Item ID:	153
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/153