Organic phosphorus defined

To illustrate the effect of outliers, consider the following simple example presented in Figure 6.1, which depicts the concentration of inorganic phosphorus and organic phosphorus in the soil [6], On this plot the classical tolerance ellipse is superimposed, defined as the set of p-dimcnsional points x whose Mahalanobis distance... 

Figure 2 The fate of phosphorus during soil formation can be viewed as the progressive dissolution of primary mineral phosphorus (dominantly apatite), some of which is lost from the system by leaching (decrease in Ptotai). and some of which is reincorporated into nonoccluded, occluded, and organic fractions within the soil. Nonoccluded phosphorus is defined as phosphate sorbed to surfaces of hydrous oxides of iron and aluminum, and calcium carbonate. Occluded phosphorus refers to phosphorus present within the mineral matrix of discrete mineral phases. The initial buildup in organic phosphorus results from organic matter return to soil from vegetation supported by the soil. The subsequent decline...

The forms of phosphorus in sediments and soils can be operationally defined by chemical extraction schemes. The major inorganic phosphorus components are considered to comprise those (i) adsorbed by exchange sites (ii) associated with iron, aluminium and manganese oxides (iii) associated with carbonate (iv) associated with calcium as apatite or (v) bound in a crystalline mineral form (e.g. silicates). The organic phosphorus fraction, on the other hand, is either considered as a whole, or operationally divided... 

We noted earlier that mass spectrometry had not been used to any extent in speciation studies of organic phosphorus in natural environments. Here we define phosphorus speciation as the determination of actual molecular formulas and structures of molecules containing phosphorus, and not the more commonly accepted, broad classes of phosphorus such as filterable reactive phosphorus, total filterable phosphorus, filterable organic phosphorus, etc. While a few studies have focused on particular classes of organic phosphorus, such as the inositol phosphates, we are not aware of any attempt to broadly speciate... 

Solution nuclear magnetic resonance (NMR) spectroscopy was introduced by Newman and Tate (1980) to define the structural composition of soil organic phosphorus. The technique allows the identification of several inorganic phosphorus forms (phosphate, pyrophosphate, polyphosphate) and organic phosphorus forms, such as phosphate monoesters (e.g. inositol phosphates and sugar phosphates), phosphate diesters (e.g. nucleic acids, phospholipids, teichoic acids) and phosphonates. 

Behrens C, Cichon MK, Grolle F, Hennecke U, Carell T (2004) Excess Electron Transfer in Defined Donor-Nucleobase and Donor-DNA-Acceptor Systems. 236 187-204 Bertrand G, Bourissou D (2002) Diphosphorus-Containing Unsaturated Three-Menbered Rings Comparison of Carbon, Nitrogen, and Phosphorus Chemistry. 220 1-25 Betzemeier B, Knochel P (1999) Perfluorinated Solvents - a Novel Reaction Medium in Organic Chemistry. 206 61-78 Bibette J, see Schmitt V (2003) 227 195-215 Blais J-C, see Astruc D (2000) 210 229-259 Bogar F, see Pipek J (1999) 203 43-61 Bohme DK, see Petrie S (2003) 225 35-73 Bourissou D, see Bertrand G (2002) 220 1-25 Bowers MT, see Wyttenbach T (2003) 225 201-226 Brand SC, see Haley MM (1999) 201 81-129... 

The living substance is constituted by six major atomic elements entering the architecture of the biochemical molecules. They are carbon, which defines the organic chemistry (that is the chemistry of what s alive), hydrogen, oxygen, nitrogen, phosphorus, and sulfur. It is necessary to add to these five other elements of mainly ionic nature included in trace elements Na (Na ), Mg (Mg ), K (K ), Ca (Ca ), Cl (CF). These ions are essential to keep the balance of aqueous biological enviromnents whether they are in intra- or extracellular enviromnents. 

Estimates of exposure levels posing minimal risk to humans (Minimal Risk Levels or MRLs) have been made for white phosphorus. An MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (noncarcinogenic) over a specified duration of exposure. MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive... 

The cycling and availability of P in estuaries is largely dependent on P specia-tion. Consequently, total P has traditionally been divided into total dissolved P and total particulate P fractions, which can be further divided into dissolved and particulate organic P and dissolved and particulate inorganic P pools. Another defined fraction within the TP pool is reactive phosphorus, which has been used to describe the potentially bioavailable P. Much of the work to date has focused on the soluble reactive P, which is characterized as the P fraction that forms a phosphomolybdate complex under acidic conditions. 

For the purpose of implementing the CWC, toxic chemicals and precursors, which have been identified for the application of verification measures, are listed in Schedules contained in the Annex on Chemicals (for the Schedules, see Chapter 2). Schedule 1 includes chemicals developed, produced, stockpiled, or used as a chemical weapon as defined above, and chemicals structurally close to them. Schedule 2 lists three toxic chemicals not included in Schedule 1 and the degradation products and precursors of these toxic chemicals as well as of those of Schedule 1. Schedule 3 lists four toxic chemicals and precursors not listed in the other Schedules. The Schedules contain mainly organic chemicals with different chemical and physical properties, being neutral chemicals, acids, bases, volatiles, and nonvolatiles, where phosphorus, fluorine, sulfur, chlorine, nitrogen, and oxygen occur frequently. Riot control agents are not included in the Schedules. 

One of the simplest methods of estimation of PolyPs in extracts is based on the assay of Pi, which is released from the PolyPs by hydrolysis with 1 M HC1 at 90 °C for 10 min. The Pi released under these conditions is defined as labile phosphorus . If the compounds containing organic labile phosphorus (i.e. nucleotide phosphates, sugar phosphates, etc.) were removed from the extracts by adsorption on Norit charcoal, the increase in Pj content after hydrolysis can be attributed to PolyP and pyrophosphate (PPi). Estimation of the PPj content (Mansurova, 1989) before hydrolysis may be needed in some cases for more precise calculations of the PolyP content. Pi may be determined by one of the well-known chemical methods (Fiske and Subarrow, 1925 Weil-Malerbe and Green, 1951). 

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