Total hydrolysable phosphorus

This determination on an unfiltered sample yields the amount of total hydrolysable phosphorus (polyphosphate) plus inorganic phosphate in true solution and also the fraction of these ions adsorbed onto particles. The latter fraction is not included when analyses are performed using filtered samples. 

Finally, phosphorus availabilities for feed materials are only partially additive, due to the curvilinear response of hydrolysis of phytate phosphorus to increasing phytase supplementation. In addition, plant phytase activity only corresponds to 60% of that of microbial phytase. A solution to these problems could be to estimate phosphorus availability by considering, firstly, the non-phytate phosphorus and secondly, by estimating the proportion of phytate hydrolysed from total phytate phosphorus and from phytase activity in the diet after heat treatment. 

Aliquots of ethanolic solution of Parathion were separated into decomposed insecticides and decomposed insecticide products. Among the products free p-nitrophenol, chemically bound in acidic phosphorus compounds and in non-hydrolysed neutral phosphorus compounds, was detected in the same way after specification. Saponification after removal of ether without separation of neutral and acidic compounds yielded total p-nitrophenyl equivalents. 

Cambella and Antia [385] determined phosphonates in seawater by fractionation of the total phosphorus. The seawater sample was divided into two aliquots. The first was analysed for total phosphorus by the nitrate oxidation method capable of breaking down phosphonates, phosphate esters, nucleotides, and polyphosphates. The second aliquot was added to a suspension of bacterial (Escherichia coli) alkaline phosphatase enzyme, incubated for 2h at 37 °C and subjected to hot acid hydrolysis for 1 h. The resultant hot acid-enzyme sample was assayed for molybdate reactive phosphate which was estimated as the sum of enzyme hydrolysable phosphate and acid hydrolysable... 

Total Phosphorus (TP) takes into account orthophosphate, polyphosphates and organic phosphate. Polyphosphates must be hydrolysed and organic phosphate oxidized into orthophosphate form, prior to analysis, usually by oxidizing agents in acid conditions. The orthophosphate content is then quantified by colorimetric method with ammonium molybdate (NF EN ISO 6878). This procedure of detection can be automated by FIA and CFA techniques (NF EN ISO 15681-1 and 2, respectively). The orthophosphate content can be estimated using various techniques including a colorimetric method (NF EN ISO 6878), ionic chromatography (NF EN ISO 10304-1), automated FIA and CFA techniques and colorimetric detection (NF EN ISO 15681-1 and 2, respectively). 

The UV/UV system has been described as an efficient method for the measurement of phosphorus in wastewater. According to the experimental conditions of photo-oxidation or UV measurement, it will be possible to evaluate the major part of phosphorus forms (oxidised, organics, inorganics, hydrolysable) and total phosphorus. Compared to the standardised method, this simple UV/UV-visible method presents some advantages especially in the time consumed, which is six times lower. Moreover, this procedure minimises the consumption of reagents and is realised in softer conditions. 

Of the esters, starch phosphate is produced by reaction with phosphorus oxychloride, polyphosphates, or metaphosphates a cross-bonded product results. Total degree of substitution is determined by measuring the phosphorus content, and the mono- to disubstitution ratio can be calculated by potentio-metric titration. Allowance is made for the natural phosphorus content of the starch. Treatment of starch with acetic anhydride produces starch acetate, which has improved paste stability over native starch. The acetyl group is very labile, and hydrolyses readily under mild alkaline conditions. When a known amount of alkali is used, the excess can be titrated and the ester function measured. This is not specific, however, and a method based on an enzymatic measurement of the acetate has been developed in an ISO work group. The modified starch is hydrolyzed under acidic conditions, which releases acetic acid and permits filtration of the resulting solution. Acetic acid is then measured by a commercially available enzyme test kit. Both bound and free acetyl groups can be measured, and the method is applicable... 

The phosphorus pentahalides can be made by the addition of halogen to the trihalides or to white phosphorus. These molecules may exist as covalent trigonal bipyramidal arrangements or in ionised tetrahedral form (3.41). The pentafluoride is the most stable it is dissociated a few percent at 100°C, and completely only at 300°C. The pentachloride, mp = 167°C, is considerably dissociated at 200°C and the pentabromide totally at 35°C. These compounds hydrolyse in at least two stages. 

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