scholarly journals Identification of lower-order inositol phosphates (IP<sub>5</sub> and IP<sub>4</sub>) in soil extracts as determined by hypobromite oxidation and solution <sup>31</sup>P NMR spectroscopy

2020 ◽  
Vol 17 (20) ◽  
pp. 5079-5095
Author(s):  
Jolanda E. Reusser ◽  
René Verel ◽  
Daniel Zindel ◽  
Emmanuel Frossard ◽  
Timothy I. McLaren
Keyword(s):  
Nmr Spectroscopy ◽  
Lower Order ◽  
Inositol Phosphates ◽  
Organic Phosphorus ◽  
31P Nmr Spectroscopy ◽  
Organic P ◽  
Soil Extracts ◽  
Broad Signal ◽  
First Time ◽  
Insight Into

Abstract. Inositol phosphates (IPs) are a major pool of identifiable organic phosphorus (P) in soil. However, insight into their distribution and cycling in soil remains limited, particularly of lower-order IP (IP5 and IP4). This is because the quantification of lower-order IP typically requires a series of chemical extractions, including hypobromite oxidation to isolate IP, followed by chromatographic separation. Here, for the first time, we identify the chemical nature of organic P in four soil extracts following hypobromite oxidation using solution 31P NMR spectroscopy and transverse relaxation (T2) experiments. Soil samples analysed include A horizons from a Ferralsol (Colombia), a Cambisol and a Gleysol from Switzerland, and a Cambisol from Germany. Solution 31P nuclear magnetic resonance (NMR) spectra of the phosphomonoester region in soil extracts following hypobromite oxidation revealed an increase in the number of sharp signals (up to 70) and an on average 2-fold decrease in the concentration of the broad signal compared to the untreated soil extracts. We identified the presence of four stereoisomers of IP6, four stereoisomers of IP5, and scyllo-IP4. We also identified for the first time two isomers of myo-IP5 in soil extracts: myo-(1,2,4,5,6)-IP5 and myo-(1,3,4,5,6)-IP5. Concentrations of total IP ranged from 1.4 to 159.3 mg P per kg soil across all soils, of which between 9 % and 50 % were comprised of lower-order IP. Furthermore, we found that the T2 times, which are considered to be inversely related to the tumbling of a molecule in solution and hence its molecular size, were significantly shorter for the underlying broad signal compared to for the sharp signals (IP6) in soil extracts following hypobromite oxidation. In summary, we demonstrate the presence of a plethora of organic P compounds in soil extracts, largely attributed to IPs of various orders, and provide new insight into the chemical stability of complex forms of organic P associated with soil organic matter.

scholarly journals Identification of lower-order inositol phosphates (IP<sub>5</sub> and IP<sub>4</sub>) in soil extracts as determined by hypobromite oxidation and solution <sup>31</sup>P NMR spectroscopy

2019 ◽  
Author(s):  
Jolanda E. Reusser ◽  
René Verel ◽  
Daniel Zindel ◽  
Emmanuel Frossard ◽  
Timothy I. McLaren
Keyword(s):  
Nmr Spectroscopy ◽  
Lower Order ◽  
31P Nmr ◽  
Inositol Phosphates ◽  
31P Nmr Spectroscopy ◽  
Organic P ◽  
Soil Extracts ◽  
Broad Signal ◽  
Solution 31P Nmr Spectroscopy ◽  
First Time

Abstract. Inositol phosphates (IP) are a major pool of identifiable organic phosphorus (P) in soil. However, insight on their distribution and cycling in soil remains limited, particularly of lower-order IP (IP5 and IP4). This is because their quantification typically requires a series of chemical extractions, including hypobromite oxidation to isolate IP, followed by chromatographic separation. Here, for the first time, we identify the chemical nature of organic P in four soil extracts following hypobromite oxidation using solution 31P NMR spectroscopy and transverse relaxation (T2) experiments. Soil samples analysed include the A horizon of a Ferralsol from Colombia, of a Cambisol from Switzerland, of a Gleysol from Switzerland and of a Cambisol from Germany. Solution 31P NMR spectra of the phosphomonoester region on soil extracts following hypobromite oxidation revealed an increase in the number of sharp signals (up to 70), and an on average 2-fold decrease in the concentration of the broad signal compared to the untreated soil extracts. We identified the presence of four stereoisomers of IP6, four stereoisomers of IP5, and scyllo-IP4 (using solution 31P NMR spectroscopy). We also identified for the first time two isomers of myo-IP5 in soil extracts: myo-(1,2,4,5,6)-IP5 and myo-(1,3,4,5,6)-IP5. Concentrations of total IP ranged from 1.4 to 159.3 mg P/kgsoil across all soils, of which between 9 % and 50 % were comprised of lower-order IP. Furthermore, we found that the T2 times, which are considered to be inversely related to the tumbling of a molecule in solution and hence its molecular size, were significantly shorter for the underlying broad signal compared to the sharp signals (IP6) in soil extracts following hypobromite oxidation. In summary, we demonstrate the presence of a plethora of organic P compounds in soil extracts, largely attributed to IP of various order, and provide new insight on the chemical stability of complex forms of organic P associated with soil organic matter.

scholarly journals Quantitative measures of myo-IP6 in soil using solution 31P NMR spectroscopy and spectral deconvolution fitting including a broad signal

2020 ◽  
Vol 22 (4) ◽  
pp. 1084-1094 ◽  
Author(s):  
Jolanda E. Reusser ◽  
René Verel ◽  
Emmanuel Frossard ◽  
Timothy I. McLaren
Keyword(s):  
Nmr Spectroscopy ◽  
31P Nmr ◽  
Inositol Phosphates ◽  
Organic Phosphorus ◽  
Terrestrial Ecosystems ◽  
31P Nmr Spectroscopy ◽  
Inositol Hexakisphosphate ◽  
Soil Organic Phosphorus ◽  
Broad Signal ◽  
Solution 31P Nmr Spectroscopy

Inositol phosphates, particularly myo-inositol hexakisphosphate (myo-IP6), are an important pool of soil organic phosphorus (P) in terrestrial ecosystems.

Organic phosphorus speciation in Australian Red Chromosols: stoichiometric control

Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald
Keyword(s):  
Organic Matter ◽  
Soil Type ◽  
Organic Phosphorus ◽  
Organic Matter Content ◽  
Matter Content ◽  
31P Nmr Spectroscopy ◽  
Chemical Forms ◽  
Organic P ◽  
Soil C ◽  
Soil P

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.

Mineralisation of soil orthophosphate monoesters under pine seedlings and ryegrass

Soil Research ◽  
2004 ◽  
Vol 42 (2) ◽  
pp. 189 ◽  
Author(s):  
C. R. Chen ◽  
L. M. Condron ◽  
B. L. Turner ◽  
N. Mahieu ◽  
M. R. Davis ◽  
...  
Keyword(s):  
31P Nmr ◽  
Inositol Phosphates ◽  
Radiata Pine ◽  
31P Nmr Spectroscopy ◽  
Organic P ◽  
Soil P ◽  
Predominant Species ◽  
Total Soil ◽  
Pine Seedlings ◽  
Solution 31P Nmr Spectroscopy

The effects of radiata pine (Pinus radiata D. Don) seedlings and ryegrass (Lolium perenne L.) on the mineralisation of orthophosphate monoesters in 7 grassland soils were assessed in a 10-month pot trial using NaOH–EDTA extraction and solution 31P NMR spectroscopy. Extraction with NaOH–EDTA recovered 46–86% of the total soil P, and NaOH–EDTA-extractable organic P determined by molybdate colourimetry ranged between 194 and 715 mg/kg soil, representing 34–85% of the total soil organic P. Orthophosphate monoesters were the predominant species of the extracted organic P in all soils, with much smaller concentrations of orthophosphate diesters, and traces of phosphonates. Concentrations of orthophosphate monoesters were consistently lower in soils under pine (103–480 mg P/kg soil) compared with the initial soils (142–598 mg P/kg soil) and most soils under grass (122–679 mg/kg soil). Mineralisation of myo-inositol hexakisphosphate accounted for 18–100% of the total mineralisation of orthophosphate monoesters in most soils under radiata pine. This suggests that supposedly recalcitrant inositol phosphates are available for uptake by radiata pine, although the extent of this varies among soils.

Spectral sensitivity of solution 31P NMR spectroscopy is improved by narrowing the soil to solution ratio to 1:4 for pasture soils of low organic P content

Geoderma ◽  
2015 ◽  
Vol 257-258 ◽  
pp. 48-57 ◽  
Author(s):  
Timothy I. McLaren ◽  
Ronald J. Smernik ◽  
Richard J. Simpson ◽  
Michael J. McLaughlin ◽  
Therese M. McBeath ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Spectral Sensitivity ◽  
31P Nmr ◽  
31P Nmr Spectroscopy ◽  
Organic P ◽  
P Content ◽  
Solution 31P Nmr Spectroscopy

31P FT-NMR of Concentrated Lake Water Samples

1997 ◽  
Author(s):  
Mark A. Nanny ◽  
Roger A. Minear
Keyword(s):  
Molecular Weight ◽  
Nmr Spectroscopy ◽  
Reverse Osmosis ◽  
Lake Water ◽  
Organic Phosphorus ◽  
Phosphorus Compounds ◽  
Lanthanum Hydroxide ◽  
Processing Times ◽  
Concentration Method ◽  
Broad Signal

The use of phosphorus-31 Fourier Transform nuclear magnetic resonance (31P FT-NMR) spectroscopy for the study of dissolved organic phosphorus (DOP) in fresh water has been recently established by Nanny and Minear. The fact that NMR is an element-specific technique, is nondestructive, and has the ability to differentiate between similar phosphorus compounds makes it invaluable for the identification and characterization of DOP. Such information regarding DOP is required in order to understand aquatic nutrient cycling. The difficulty with using 31P FT-NMR spectroscopy for such studies is the extremely low DOP concentration; usually ranging from < 1 μg P/L in oligotrophic lakes to approximately 100 μg P/L for eutrophic systems. Nanny and Minear raised the DOP concentration into the NMR detection range, which is on the order of milligrams of phosphorus/liter, by concentrating large volumes of lake water with ultrafiltration (UF) and reverse osmosis (RO) membranes. Volume concentration factors of several ten thousand fold provided DOP concentrations of up to 60 mg P/L. Other DOP concentration methods such as anion exchange, lanthanum hydroxide precipitation, and lyophilization require severe chemical and/or physical transformations of the sample and/or they need long processing times, all of which increase the risk of DOP hydrolysis. Sample concentration with UF and RO membranes does not require the sample to undergo these major changes and is also a relatively rapid concentration method. In addition to these concentration capabilities, the use of ultrafiltration and reverse osmosis membranes permitted fractionation of the DOP samples according to molecular size. Nanny and Minear used three membranes in series with decreasing pore size: 30kDa (kilodaltons), 1 kDa, and RO (95% NaCl rejection) to separate the high-molecular-weight, intermediate-molecular-weight, and low-molecular-weight DOP species. In the intermediate-molecular-weight fraction, Nanny and Minear observed the presence of monoester and diester phosphates. Spectra from ten samples collected over a year typically consisted of a large broad signal in the monoester phosphate region spanning from a chemical shift of 2.00 ppm to −0.50 ppm. The maximum of this signal was usually in the range of 1.00 to 1.50 ppm. This broad signal had a shoulder in the diester phosphate region which sometimes was intense enough to appear as an individual signal.

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