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Sergey V Dorozhkin - One of the best experts on this subject based on the ideXlab platform.
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multiphasic calcium Orthophosphate capo4 bioceramics and their biomedical applications
Ceramics International, 2016Co-Authors: Sergey V DorozhkinAbstract:Abstract Due to the chemical similarity to the inorganic constituents of calcified tissues of mammals, biologically relevant calcium Orthophosphates (CaPO 4 ) have been applied as artificial bioceramics suitable for reconstruction of various types of bone defects. Since none of the known individual types of CaPO 4 appears to be able to mimic both the composition and the properties of natural bones, various attempts have been sought to overcome this problem and a multiphasic (polyphasic) concept is one of the reasonable solutions. In general, this approach is determined by advantageous formulations consisting of homogeneous blends of two (biphasic), three (triphasic) or more (multiphasic) individual CaPO 4 phases possessing diverse solubility and, therefore, bioresorbability, while the optimum ratios among the phases depend on the definite applications. Therefore, all currently known multiphasic CaPO 4 formulations are sparingly soluble in water and, thus, after being implanted they are gradually resorbed inside the body, releasing calcium and Orthophosphate ions into the biological medium and, hence, seeding a new bone formation. They have already demonstrated a proven biocompatibility, osteoconductivity, safety and predictability in vitro , in vivo , as well as in clinical trials. More recently, in vitro and in vivo studies have shown that some of them might possess osteoinductive properties. Hence, in tissue engineering, multiphasic CaPO 4 bioceramics represent promising formulations to construct various scaffolds capable of carrying and/or modulating the behavior of cells. This review summarizes the available information on biphasic, triphasic and multiphasic CaPO 4 bioceramics including their biomedical applications. New formulations have been proposed as well.
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calcium Orthophosphate coatings on magnesium and its biodegradable alloys
Acta Biomaterialia, 2014Co-Authors: Sergey V DorozhkinAbstract:Biodegradable metals have been suggested as revolutionary biomaterials for bone-grafting therapies. Of these metals, magnesium (Mg) and its biodegradable alloys appear to be particularly attractive candidates due to their non-toxicity and as their mechanical properties match those of bones better than other metals do. Being light, biocompatible and biodegradable, Mg-based metallic implants have several advantages over other implantable metals currently in use, such as eliminating both the effects of stress shielding and the requirement of a second surgery for implant removal. Unfortunately, the fast degradation rates of Mg and its biodegradable alloys in the aggressive physiological environment impose limitations on their clinical applications. This necessitates development of implants with controlled degradation rates to match the kinetics of bone healing. Application of protective but biocompatible and biodegradable coatings able to delay the onset of Mg corrosion appears to be a reasonable solution. Since calcium Orthophosphates are well tolerated by living organisms, they appear to be the excellent candidates for such coatings. Nevertheless, both the high chemical reactivity and the low melting point of Mg require specific parameters for successful deposition of calcium Orthophosphate coatings. This review provides an overview of current coating techniques used for deposition of calcium Orthophosphates on Mg and its biodegradable alloys. The literature analysis revealed that in all cases the calcium Orthophosphate protective coatings both increased the corrosion resistance of Mg-based metallic biomaterials and improved their surface biocompatibility.
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calcium Orthophosphates occurrence properties biomineralization pathological calcification and biomimetic applications
Biomatter, 2011Co-Authors: Sergey V DorozhkinAbstract:The present overview is intended to point the readers' attention to the important subject of calcium Orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium Orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium Orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium Orthophosphates. Thus, calcium Orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided.
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amorphous calcium ortho phosphates
Acta Biomaterialia, 2010Co-Authors: Sergey V DorozhkinAbstract:Amorphous calcium phosphates (ACPs) represent a unique class of biomedically relevant calcium Orthophosphate salts, having variable chemical but essentially identical glass-like physical properties, in which there is neither translational nor orientational long-range ordering of the atomic positions. Normally, ACPs are the first solid phases, precipitated after a rapid mixing of aqueous solutions containing ions of Ca(2+) and PO₄³⁻; however, other production techniques are known. Interestingly, ACPs prepared by wet-chemical techniques were found to have a relatively constant chemical composition over a relatively wide range of preparation conditions, which suggests the presence of a well-defined local structural unit, presumably with the structure of Ca₉(PO₄)₆ - so-called Posner cluster. However, the presence of similar clusters in ACPs produced by other techniques remains uncertain. All ACPs are thermodynamically unstable compounds and, unless stored in dry conditions or doped by stabilizers, spontaneously tend to transform to crystalline calcium Orthophosphates, mainly to calcium apatites. This solution instability of ACPs and their easy transformation to crystalline phases are of a great biological relevance. Specifically, the initiating role ACPs play in matrix vesicle biomineralization raises the importance of ACPs from a mere laboratory curiosity to that of a key intermediate in skeletal calcification. In addition, due to significant chemical and structural similarities with calcified mammalian tissues, as well as excellent biocompatibility and bioresorbability, all types of ACPs are very promising candidates for the manufacture of artificial bone grafts. This review summarizes the current knowledge on the occurrence, preparation, composition, structure, major properties and biomedical applications of ACPs. To assist readers in looking for the specific details on ACPs, a great number of references have been collected and systematized.
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calcium Orthophosphates in nature biology and medicine
Materials, 2009Co-Authors: Sergey V DorozhkinAbstract:The present overview is intended to point the readers’ attention to the important subject of calcium Orthophosphates. These materials are of the special significance because they represent the inorganic part of major normal (bones, teeth and dear antlers) and pathological (i.e. those appearing due to various diseases) calcified tissues of mammals. Due to a great chemical similarity with the biological calcified tissues, many calcium Orthophosphates possess remarkable biocompatibility and bioactivity. Materials scientists use this property extensively to construct artificial bone grafts that are either entirely made of or only surface-coated with the biologically relevant calcium Orthophosphates. For example, self-setting hydraulic cements made of calcium Orthophosphates are helpful in bone repair, while titanium substitutes covered by a surface layer of calcium Orthophosphates are used for hip joint endoprostheses and as tooth substitutes. Porous scaffolds made of calcium Orthophosphates are very promising tools for tissue engineering applications. In addition, technical grade calcium Orthophosphates are very popular mineral fertilizers. Thus ere calcium Orthophosphates are of great significance for humankind and, in this paper, an overview on the current knowledge on this subject is provided.
Benjamin L. Turner - One of the best experts on this subject based on the ideXlab platform.
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phosphorus compounds in subarctic fennoscandian soils at the mountain birch betula pubescens tundra ecotone
Soil Biology & Biochemistry, 2004Co-Authors: Benjamin L. Turner, N Mahieu, Robert Baxter, Sofie Sjogersten, Brian A WhittonAbstract:Abstract Nutrient availability will partly regulate the response of high latitude ecosystems to climate warming, but phosphorus biogeochemistry is poorly understood in Arctic soils. We used NaOH–EDTA extraction and solution 31 P nuclear magnetic resonance (NMR) spectroscopy to determine phosphorus compounds in subarctic soils from three locations in the Fennoscandian mountains contrasting in latitude and continentality. Soils were taken from open tundra and mountain birch ( Betula pubescens Ehrh.) forest at each location. Between 87 and 95% of the total phosphorus was extracted from the surface 2 cm of the organic soil horizons. Most of the extracted phosphorus was Orthophosphate monoesters (44–55%), with smaller concentrations of inorganic Orthophosphate (15–24%), Orthophosphate diesters (12–16%), pyrophosphate (3–18%), inorganic polyphosphate (0–15%) and phosphonates (0–4%). The Orthophosphate diesters were further subclassified into DNA (9–13% extracted phosphorus) and phospholipids (1–6% extracted phosphorus), although strong signals in the Orthophosphate monoester region of the spectra, consistent with the degradation of phosphatidyl choline in alkaline solution, suggested that phospholipid concentrations were substantially underestimated. The phosphorus composition was broadly similar among soils from the three locations, although no phosphonates were detected in tundra soils from the most southerly site. Deeper organic horizons tended to contain a greater proportion of Orthophosphate monoesters than at the surface. The abundance of phosphorus compounds that would be considered readily degradable in temperate environments probably reflects the slow organic matter decomposition in these cold, acidic soils, and suggests that phosphorus availability is unlikely to limit ecosystem productivity on mesic soils at the birch-tundra ecotone during changes induced by climate warming.
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optimizing phosphorus characterization in animal manures by solution phosphorus 31 nuclear magnetic resonance spectroscopy
Journal of Environmental Quality, 2004Co-Authors: Benjamin L. TurnerAbstract:A procedure involving alkaline extraction and solution 31P nuclear magnetic resonance (NMR) spectroscopy was developed and optimized for the characterization of P in animal manures (broiler, swine, beef cattle). Inclusion of ethylenediaminetetraacetic acid (EDTA) in the alkaline extraction solution recovered between 82 and 97% of the total P from the three manures, which represented a significant improvement on recovery in NaOH alone. Low concentrations of paramagnetic ions in all manure extracts meant that relatively long delay times (>5 s) were required for quantitative analysis by solution 31P NMR spectroscopy. The manures contained inorganic Orthophosphate, Orthophosphate monoesters, Orthophosphate diesters, and inorganic polyphosphates, but results were markedly influenced by the concentration of NaOH in the extractant, which affected both spectral resolution and the apparent P composition of the extracts. For example, extraction of swine manure and broiler litter with 0.5 M NaOH + 50 mM EDTA produced remarkable spectral resolution that allowed accurate quantification of the four signals from phytic acid, the major organic P compound in these manures. In contrast, more dilute NaOH concentrations produced considerable line broadening that obscured individual signals in the Orthophosphate monoester region of the spectra. Spectral resolution of cattle manure extracts was relatively unaffected by NaOH concentration. Improvements in spectral resolution of more concentrated NaOH extracts were, however, compromised by the disappearance of phospholipids and inorganic polyphosphates, notably in swine and cattle manure extracts, which indicated either degradation or a change in solubility. The optimum extraction conditions will therefore vary depending on the manure type and the objectives of the study. Phytic acid can be accurately quantified in swine manure and broiler litter by extraction with 0.5 M NaOH + 50 mM EDTA, while a more dilute NaOH concentration should be used for complete P characterization or comparison among different manure types.
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phosphorus composition of upland soils polluted by long term atmospheric nitrogen deposition
Biogeochemistry, 2003Co-Authors: Benjamin L. Turner, John A Chudek, Brian A Whitton, Robert BaxterAbstract:Atmospheric N deposition can enhance biological P limitation in terrestrial ecosystems and increase the importance of organic P to plants and microorganisms. We used NaOH–EDTA extraction and solution 31P NMR spectroscopy to determine the P composition of soils in the Upper Teesdale National Nature Reserve, northern England, an upland region influenced by such deposition for at least 150 years. Three characteristic soil types were sampled on three occasions during an annual cycle: blanket peat (318 mg g−1 total C, 607 μg g−1 total P, pH 3.9); acid organic soil under grassland (354 mg g−1 total C, 1190 μg g−1 total P, pH 3.7); calcareous soil under grassland (140 mg g−1 total C, 649 μg g−1 total P, pH 7.3). Between 58 and 99% of the total P in soil and litter layers was extracted by 0.25 M NaOH + 0.05 M EDTA. Extracts of all soils were dominated by organic P, mainly in the form of Orthophosphate monoesters (43–69% extracted P). The two acidic soils also contained large proportions of Orthophosphate diesters (6–19% extracted P) and phosphonates (7–16% extracted P), suggesting that these compounds become stabilised at low pH. However, a seasonal trend of increasing Orthophosphate monoester-to-diester ratios, most evident in the calcareous grassland soil, indicated the preferential degradation of Orthophosphate diesters during the growing season. Orthophosphate was the major inorganic P compound (17–34% extracted P), and all soils contained pyrophosphate (1–5% extracted P). However, Orthophosphate determined in the NaOH–EDTA extracts by solution 31P NMR spectroscopy was substantially greater than that determined by molybdate colourimetry, suggesting that Orthophosphate occurred in complexes with humic compounds that were not detected by conventional procedures. Our results suggest that organisms able to use recalcitrant soil organic P may have a competitive advantage in environments under enhanced atmospheric N deposition.
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the phosphorus composition of temperate pasture soils determined by naoh edta extraction and solution 31p nmr spectroscopy
Organic Geochemistry, 2003Co-Authors: Benjamin L. Turner, N Mahieu, Leo M CondronAbstract:Information on the composition and dynamics of soil phosphorus (P) remains limited, but is integral to understanding soil biogeochemical cycles. We used solution 31P nuclear magnetic resonance (NMR) spectroscopy to characterise NaOH–EDTA extractable P in 29 permanent pasture soils from England and Wales (total carbon 29–80 g kg−1 soil, clay 219–681 g kg−1 soil, pH 4.4–6.8). Total P ranged between 376 and 1981 mg P kg−1 soil, of which between 45 and 88% was extracted with NaOH–EDTA. The extracts were dominated by Orthophosphate monoesters (29–60% extracted P) and inorganic Orthophosphate (21–55% extracted P), with smaller concentrations of Orthophosphate diesters (2–10% extracted P), pyrophosphate (1–7% extracted P), phosphonates (0–3% extracted P), and traces of polyphosphates. Orthophosphate diesters were subclassified into phospholipids (1–7% extracted P) and DNA (1–6% extracted P). Signals slightly downfield of inorganic Orthophosphate were tentatively assigned to aromatic Orthophosphate diesters similar in structure to R-(−)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate. Such signals are rarely detected in soil extracts, but were present in relatively large concentrations in the samples analysed here (2–5% extracted P). Relationships between functional P groups and soil properties suggested that the various functional groups are involved in the soil P cycle to different extents. In particular, concentrations of Orthophosphate monoesters appeared to be controlled by the potential for chemical stabilisation in soil, whereas DNA and pyrophosphate were strongly correlated with the microbial biomass, suggesting an active involvement in biological nutrient turnover.
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phosphorus 31 nuclear magnetic resonance spectral assignments of phosphorus compounds in soil naoh edta extracts
Soil Science Society of America Journal, 2003Co-Authors: Benjamin L. Turner, N Mahieu, Leo M CondronAbstract:Soil P composition can be conveniently determined in alkaline extracts using solution 31 P nuclear magnetic resonance (NMR) spectroscopy, but spectral assignments are based on fragmentary literature reports of model compounds in various extraction matrices. We report solution 31 P 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 31 P NMR spectroscopy of soil extracts be performed at 20°C.
Barbara J Cademenun - One of the best experts on this subject based on the ideXlab platform.
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improved peak identification in 31p nmr spectra of environmental samples with a standardized method and peak library
Geoderma, 2015Co-Authors: Barbara J CademenunAbstract:The technique of 31P-NMR spectroscopy has done more to advance the knowledge of organic P forms in environmental samples than any other method. Early 31P-NMR work limited identification to peaks that were clearly separated, such as Orthophosphate and pyrophosphate, grouping the remaining peaks into broad categories such as Orthophosphate monoesters and Orthophosphate diesters. Advances in 31P-NMR methodology for environmental samples now produce clearer spectra, providing the potential to identify more peaks. However, there is at present no standard method for peak identification, and no library of chemical shifts of P forms analyzed under standardized, easily replicated conditions. Various research groups have conducted spiking experiments and have developed their own peak libraries. However, because the chemical shifts of P forms are affected by sample conditions such as pH and salt concentration, it can be difficult to use the work of one lab group to identify P forms in samples analyzed by another lab group under different conditions. For this paper, more than 50 P compounds were analyzed under standardized conditions that can easily be repeated by other research groups. These compounds include phosphonates, Orthophosphate monoesters, Orthophosphate diesters, polyphosphates, pyrophosphate, and a compound with an N–P bond. The chemical shifts of P forms analyzed for this P compound library were compared to those identified elsewhere, if available. In addition, recommendations are given for standardized spiking experiments to improve peak identification.
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phosphorus speciation in a eutrophic lake by 31p nmr spectroscopy
Water Research, 2014Co-Authors: Emily K Read, Barbara J Cademenun, Monika Ivancic, Paul C Hanson, Katherine D McmahonAbstract:For eutrophic lakes, patterns of phosphorus (P) measured by standard methods are well documented but provide little information about the components comprising standard operational definitions. Dissolved P (DP) and particulate P (PP) represents important but rarely characterized nutrient pools. Samples from Lake Mendota, Wisconsin, USA were characterized using 31-phosphorus nuclear magnetic resonance spectroscopy ((31)P NMR) during the open water season of 2011 in this unmatched temporal study of aquatic P dynamics. A suite of organic and inorganic P forms was detected in both dissolved and particulate fractions: Orthophosphate, Orthophosphate monoesters, Orthophosphate diesters, pyrophosphate, polyphosphate, and phosphonates. Through time, phytoplankton biomass, temperature, dissolved oxygen, and water clarity were correlated with changes in the relative proportion of P fractions. Particulate P can be used as a proxy for phytoplankton-bound P, and in this study, a high proportion of polyphosphate within particulate samples suggested P should not be a limiting factor for the dominant primary producers, cyanobacteria. Hypolimnetic particulate P samples were more variable in composition than surface samples, potentially due to varying production and transport of sinking particles. Surface dissolved samples contained less P than particulate samples, and were typically dominated by Orthophosphate, but also contained monoester, diester, polyphosphate, pyrophosphate, and phosphonate. Hydrologic inflows to the lake contained more Orthophosphate and Orthophosphate monoesters than in-lake samples, indicating transformation of P from inflowing waters. This time series explores trends of a highly regulated nutrient in the context of other water quality metrics (chlorophyll, mixing regime, and clarity), and gives insight on the variability of the structure and occurrence of P-containing compounds in light of the phosphorus-limited paradigm.
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phosphorus speciation in riparian soils a phosphorus 31 nuclear magnetic resonance spectroscopy and enzyme hydrolysis study
Soil Science Society of America Journal, 2013Co-Authors: Eric O Young, Barbara J Cademenun, Donald S Ross, Corey W LiuAbstract:In the Lake Champlain Basin, phosphorus (P) loading from streambank erosion and cropland are both important P sources, and a better understanding of the factors affecting riparian P loss is needed to help prioritize riparian restoration efforts. We utilized solution phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy and an enzyme hydrolysis method to characterize P and assess bioavailability in 14 commonly mapped riparian soils from northwestern Vermont. Surface horizons were sampled from distinct series at two riparian restoration sites to capture a range of soil properties. Samples were extracted with sodium hydroxide–ethylenediaminetetra-acetic acid (NaOH-EDTA) and analyzed by solution ³¹P NMR to speciate and quantify P compounds, and commercially available phosphatase enzymes were used to fractionate water-extractable molybdate unreactive P (MUP) into labile Orthophosphate monoesters and Orthophosphate diesters. Phosphorus extracted by NaOH-EDTA ranged from 74 to 510 mg P kg⁻¹ (representing 14.2 to 31.9% of total soil P), of which 58 ± 13% was identified as organic P. Phosphorus compounds identified in all samples included myo-inositol hexakisphosphate (myo-IHP), scyllo-IHP, neo-IHP, chir-IHP, glycerophosphate, glucose 6-phosphate, mononucleotides, choline phosphate, glucose 1-phosphate, DNA, pyrophosphate, and Orthophosphate. Orthophosphate monoesters accounted for 53.7 ± 12.3% of total NaOH-EDTA extractable P and 93 ± 3% of the NaOH-EDTA organic P, indicating the importance of organic P in these soils. Stereoisomers of IHP accounted for 29 ± 7% of NaOH-EDTA extractable Pₒ. For the water extractions, 78 ± 13% of total P was MUP, of which 18 ± 6% was labile Orthophosphate monoesters and 31 ± 15% was Orthophosphate diesters. Results suggest that analytical indices of riparian P loss potential should consider both organic and inorganic P.
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comparison of phosphorus forms in wet and dried animal manures by solution phosphorus 31 nuclear magnetic resonance spectroscopy and enzymatic hydrolysis
Journal of Environmental Quality, 2007Co-Authors: Zhongqi He, Wayne C Honeycutt, Barbara J Cademenun, Annmarie Fortuna, Gurpal S Toor, Thomas J SimsAbstract:Both enzymatic hydrolysis and solution 31 P nuclear magnetic resonance (NMR) spectroscopy have been used to characterize P compounds in animal manures. In this study, we comparatively investigated P forms in 0.25 M NaOH/0.05 M EDTA extracts of dairy and poultry manures by the two methods. For the dairy manure, enzymatic hydrolysis revealed that the majority of extracted P was inorganic P (56%), with 10% phytate-like P, 9% simple monoester P, 6% polynucleotidelike P, and 18% non-hydrolyzable P. Similar results were obtained by NMR spectroscopy, which showed that inorganic P was the major P fraction (64–73%), followed by 6% phytic acid, 14 to 22% other monoesters, and 7% phosphodiesters. In the poultry manure, enzymatic hydrolysis showed that inorganic P was the largest fraction (71%), followed by 15% phytate-like P and 1% other monoesters, and 3% polynucleotide-like P. NMR spectroscopy revealed that Orthophosphate was 51 to 63% of extracted P, phytic acid 24 to 33%, other phosphomonoesters 6 to 12%, and phospholipids and DNA 2% each. Drying process increased Orthophosphate (8.4% of total P) in dairy manure, but decreased Orthophosphate (13.3% of total P) in poultry manure, suggesting that drying treatment caused the hydrolysis of some organic P to Orthophosphate in dairy manure, but less recovery of Orthophosphate in poultry manure. Comparison of these data indicates that the distribution patterns of major P forms in animal manure determined by the two methods were similar. Researchers can utilize the method that best fits their specific research goals or use both methods to obtain a full spectrum of manure P characterization.
Leo M Condron - One of the best experts on this subject based on the ideXlab platform.
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the phosphorus composition of temperate pasture soils determined by naoh edta extraction and solution 31p nmr spectroscopy
Organic Geochemistry, 2003Co-Authors: Benjamin L. Turner, N Mahieu, Leo M CondronAbstract:Information on the composition and dynamics of soil phosphorus (P) remains limited, but is integral to understanding soil biogeochemical cycles. We used solution 31P nuclear magnetic resonance (NMR) spectroscopy to characterise NaOH–EDTA extractable P in 29 permanent pasture soils from England and Wales (total carbon 29–80 g kg−1 soil, clay 219–681 g kg−1 soil, pH 4.4–6.8). Total P ranged between 376 and 1981 mg P kg−1 soil, of which between 45 and 88% was extracted with NaOH–EDTA. The extracts were dominated by Orthophosphate monoesters (29–60% extracted P) and inorganic Orthophosphate (21–55% extracted P), with smaller concentrations of Orthophosphate diesters (2–10% extracted P), pyrophosphate (1–7% extracted P), phosphonates (0–3% extracted P), and traces of polyphosphates. Orthophosphate diesters were subclassified into phospholipids (1–7% extracted P) and DNA (1–6% extracted P). Signals slightly downfield of inorganic Orthophosphate were tentatively assigned to aromatic Orthophosphate diesters similar in structure to R-(−)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate. Such signals are rarely detected in soil extracts, but were present in relatively large concentrations in the samples analysed here (2–5% extracted P). Relationships between functional P groups and soil properties suggested that the various functional groups are involved in the soil P cycle to different extents. In particular, concentrations of Orthophosphate monoesters appeared to be controlled by the potential for chemical stabilisation in soil, whereas DNA and pyrophosphate were strongly correlated with the microbial biomass, suggesting an active involvement in biological nutrient turnover.
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phosphorus 31 nuclear magnetic resonance spectral assignments of phosphorus compounds in soil naoh edta extracts
Soil Science Society of America Journal, 2003Co-Authors: Benjamin L. Turner, N Mahieu, Leo M CondronAbstract:Soil P composition can be conveniently determined in alkaline extracts using solution 31 P nuclear magnetic resonance (NMR) spectroscopy, but spectral assignments are based on fragmentary literature reports of model compounds in various extraction matrices. We report solution 31 P 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 31 P NMR spectroscopy of soil extracts be performed at 20°C.
Thomas J Sims - One of the best experts on this subject based on the ideXlab platform.
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comparison of phosphorus forms in wet and dried animal manures by solution phosphorus 31 nuclear magnetic resonance spectroscopy and enzymatic hydrolysis
Journal of Environmental Quality, 2007Co-Authors: Zhongqi He, Wayne C Honeycutt, Barbara J Cademenun, Annmarie Fortuna, Gurpal S Toor, Thomas J SimsAbstract:Both enzymatic hydrolysis and solution 31 P nuclear magnetic resonance (NMR) spectroscopy have been used to characterize P compounds in animal manures. In this study, we comparatively investigated P forms in 0.25 M NaOH/0.05 M EDTA extracts of dairy and poultry manures by the two methods. For the dairy manure, enzymatic hydrolysis revealed that the majority of extracted P was inorganic P (56%), with 10% phytate-like P, 9% simple monoester P, 6% polynucleotidelike P, and 18% non-hydrolyzable P. Similar results were obtained by NMR spectroscopy, which showed that inorganic P was the major P fraction (64–73%), followed by 6% phytic acid, 14 to 22% other monoesters, and 7% phosphodiesters. In the poultry manure, enzymatic hydrolysis showed that inorganic P was the largest fraction (71%), followed by 15% phytate-like P and 1% other monoesters, and 3% polynucleotide-like P. NMR spectroscopy revealed that Orthophosphate was 51 to 63% of extracted P, phytic acid 24 to 33%, other phosphomonoesters 6 to 12%, and phospholipids and DNA 2% each. Drying process increased Orthophosphate (8.4% of total P) in dairy manure, but decreased Orthophosphate (13.3% of total P) in poultry manure, suggesting that drying treatment caused the hydrolysis of some organic P to Orthophosphate in dairy manure, but less recovery of Orthophosphate in poultry manure. Comparison of these data indicates that the distribution patterns of major P forms in animal manure determined by the two methods were similar. Researchers can utilize the method that best fits their specific research goals or use both methods to obtain a full spectrum of manure P characterization.
