Estimation of phosphorus

The simultaneous analysis of orthophosphate, glycerol phosphates, and inositol phosphates has been achieved by spectrophotometric analysis of the molybdovanadate complexes. Also, a sensitive and selective chemiluminescent molecular emission method for the estimation of phosphorus and sulphur is described, which is based on passing solutions into a cool, reducing, nitrogen-hydrogen diffusion flame. For organic compounds it was usually necessary to prepare test solutions by an oxygen-flask combustion technique. 

In comparison, our measurements of epilimnetic zooplankton biomass over the study period (3540 mg/m2), combined with Scavia s (7) weight-specific zooplankton regeneration rate of 1.7 xg of P/mg per day, give a flux of —800 mg of P/m2. These estimates of phosphorus excretion rates are similar to our carbon-based phosphorus demand. 

Kraft, C. E. Estimation of Phosphorus Cycling by Fish Using a Bioenergetics Modeling Approach. Ph.D. Thesis. University of Wisconsin—Madison, Madison, WI, 1991. 

Perez-Martinez, C., van Tongeren, O. F. R., and Gulati, R. (1995). Estimation of phosphorus metabohc rates of using a three-component model. J. Plankton Res. 17, 1605—1619. 

The estimation of phosphorus by g.l.c. has been reviewed. Cyclic phosphites, phosphonates, and phosphates have been analysed by g.l.c. The zinc, gold, and cadmium chelates of dialkyl dithiophosphinates (235 ... 

Development of molybdenum blue colour (pH adjustment in the test solution if pH is at appreciable variance from 3). For precise estimation of phosphorus, an aliquot of the P- containing test solution is pipetted in a 25 ml volumetric flask, adjusted to pH 3 with 4(N) NH OH or 4(N) HCl using 2 4 dinitrophenol as an indicator (0.25% in HgO) which becomes yellow as pH = 3 is approached from the acid side. If with few drops of indicator yellow colouration is obtained acid is added drop wise until colourless. If the indicator gives a colourless solution indicating a solution pH below 3 drop wise alkali is added just until a yellow colour appears and finally this yellow colour is made faint yellow with dropwise additon of the acid solution. 

Chemical methods for the detection and estimation of phosphorus in a compound are many and varied, but they usually require the phosphorus to be first obtained in the form of inorganic orthophosphate. For this, a prior oxidation and/or hydrolysis may have to be carried out. Insoluble phosphates are dissolved in mineral acids, with boiling if necessary. In some cases, fusion with alkaline fluxes (e.g. boric acid and sodium carbonate at lOOO C) is needed, followed by water or acid extraction of the soluble phosphates produced. Cation exchange resins may sometimes be used to convert insoluble into soluble phosphate salts. Numerous extraction and clean-up procedures have been prescribed for determination of the P content of compounds of bio origin. Pre-treatment of the sample by chemical methods is sometimes a necessary procedure before examination by physical methods (e.g. spectrophotometty), can be undertaken. 

Detailed analytical procedures have been evolved for the estimation of phosphorus in such diverse materials as drinking water, sea water, food products, plants, concrete, ores and rocks, oils, metals, pesticides and fertilizers. Each of these materials has its own special analytical requirements. In the case of fertilizers, for example, it is usual to estimate (a) water-soluble phosphate which relates to available phosphorus and (b) citrate-insoluble phosphate which is a measure of the phosphorus which plants cannot utilise. In the case of seawater, both dissolved P and particulate P content may be estimated. 

A scheme of activation analysis usually includes a chemical separation process or the addition of a carrier . It is sometimes desirable to remove chemically, before activation, any elements which would cause interference. For example, the presence of sulphur or chlorine in the sample could cause inaccuracies in the estimation of phosphorus content due to reactions (13.216) and (13.217) taking place and providing extra radioactive phosphorus. In a similar manner silicon can also cause interference with the phosphorus estimation owing to the side reaction. 

Feedbacks may be affected directly by atmospheric CO2, as in the case of possible CO2 fertilization of terrestrial production, or indirectly through the effects of atmospheric CO2 on climate. Furthermore, feedbacks between the carbon cycle and other anthropogenically altered biogeochemical cycles (e.g., nitrogen, phosphorus, and sulfur) may affect atmospheric CO2. If the creation or alteration of feedbacks have strong effects on the magnitudes of carbon cycle fluxes, then projections, made without consideration of these feedbacks and their potential for changing carbon cycle processes, will produce incorrect estimates of future concentrations of atmospheric CO2. 

Figure 5.15. Gas chromatograms of liquid precursors for producing n-type Si films, namely, solution of CPS with white phosphorus dissolved at 1 wt% initial (nonirradiated) solution 20-min-, 25-min-, and 30-min-irradiated solutions and white phosphorus alone solution, for comparison, all of which were diluted with toluene before analysis. Trans-decalin was used as a standard for a quantitative estimation of an unreacted CPS monomer. [Reproduced with permission from Ref. 25. Copyright 2007 The Japan Society of Applied Physics.]...

Human activity has an enormous influence on the global cycling of nutrients, especially on the movement of nutrients to estuaries and other coastal waters. For phosphorus, global fluxes are dominated by the essentially one way flow of phosphorus carried in eroded materials and wastewater from the land to the oceans, where it is ultimately buried in ocean sediments. The size of this flux is currently estimated at 22 x 106 tons per year. Prior to increased human agricultural and industrial activity,... 

Ruider and Spatzierer [57] described a simple method for the rapid estimation of nitrogen and phosphorus. They discuss the usefulness of test kits for ammonia nitrogen, nitrate nitrogen and phosphorus. 

Allen, R. J. L. (1940). Micro-determination of phosphorus. (Colorimetric estimation molybdate blue.) Biochem. J. 34, 858. Bellamy, L. J. (1954). Infra-red Spectra of Complex Molecules. Methuen and Co. 

It is known that four-membered rings containing phosphorus or sulphur are formed more readily than those containing only first-row elements, and the EM s calculated for compounds A.6.1 and 2 allow a quantitative estimate of the importance of the effect. In this series the four-membered ring is formed almost as efficiently as the five [the EM for the hydrolysis of H02C(CH2)j SOjNMePh (A.6.3) is 2 x 107 M]... 

Another phosphorus containing CDA (87) has also been described for the estimation of the enantiomeric excess of chiral amines80. The phosphorus CDA 87 is formed quantitatively and instantaneously in situ in an NMR tube by reaction of phosphorus trichloride (PCI3) with the chiral diamine 88. Addition to the NMR tube of the chiral amine (IC-NIIo) for which the ee is to be determined gives the diastereomeric phosphorous derivatives ... 

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