Analysis of Condensed Phosphates

Since all condensed phosphates are ultimately degraded to monophosphate in hot solution, especially at low pH, the total phosphorus(V) content of a substance may readily be determined after hydrolysis either gravimetrically or titrimetrically (109). However, as soon as it is a question of estimating the content of separate components in mixtures of condensed phosphates insuperable difficulties are encountered if methods depending on precipitation, titration, or a combination of the two are used. Even a quantitative precipitation of monophosphate is impossible if polyphosphates with chain length of n = 3 or more arc present in the solution. The precipitating cation and the compound to be precipitated by it are partly kept in solution by the polyphosphate part of the polyphosphate is also carried down by the precipitate. Both of these effects depend in their extent in different ways on the nature and quantity of the substances present and the analysis gives a correct quantitative result only in isolated instances 

Provided only polyphosphates are present it is possible to determine titrimetrically (1) the end-group content of mixtures (2) the content of groups within the chain, after hydrolysis and by estimating the total phosphate content (3) the monophosphate content after precipitation with silver nitrate (347). These methods are likewise of no use in presence of meta- and cross-linked phosphates. 

Since most technical products always contain the same constituents in approximately the same amounts it has been possible to develop numerous empirical methods which, for the most part, involve a combined procedure based on precipitation and titrimetric determinations. These are of practical use for particular purposes, e.g., in comparative determinations, but have no claims to general validity (4, 9, 68, 70, 71, 75, 87, 187, 236, 240, 352). 

One of the special methods mentioned above may be used in determining the two forms of sodium triphosphate, one of which (Na6P3Oio(I)) is unde- 

Introduction of the technique of labeling the phosphate with radioactive P32 finally facilitated the quantitative determination of separate components, the quantities of which were previously determined colorimetri-cally after eluting the chromatogram spots with ammonia (171,192). 

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P shows magnetic properties similar to 1H and 19F 31P with l = 1/2 exhibits sharp NMR peaks with chemical shifts extending over range of 700 ppm, 31P NMR has been used in the quantitative analysis of condensed phosphates, hydroxymethyl phosphines and thiophosphates. 

The most recent proposal for analysis of condensed phosphates depends on the examination of nuclear magnetic resonance spectra (43, 343). 

Y. Sekiguchi, A. Matsunaga, A. Yamamoto and Y. Inoue (2000). Analysis of condensed phosphates in food products by ion chromatography with an on-line hydroxide eluent generator. J. Chromatogr., 881, 639-644. 

Fig. 8-52. Analysis of condensed phosphates in detergents. - Separator column IonPac AS7 eluent 0.07 mol/L HN03 flow rate 0.5 mL/min detection photometry at 330 nm after reaction with ferric nitrate injection 50 pL of a 0.1% washing powder solution.

The analysis of condensed phosphates in the totally ionized form, especially together with standard inorganic anions, is possible only by utilizing gradient elution and suppressed conductivity detection, because the retention behavior... 

Reliable identification of polyphosphates often includes the Thilo and Wicker method of chromatographic analysis of the products of partial hydrolysis (Thilo and Wicker, 1957). In this approach, the hydrolysis of condensed phosphates in neutral solution at 60 °C yields... 

A quantitative analysis of the phosphate separated on the paper was done by Smith s method (42). Lucena-Conde and Prat s reagent (43) was successfully employed for the colorimetric determination of orthophosphate or condensed phosphates eluted from the sheet of paper. 

The hydrolysis of condensed phosphates during the orthophosphate analysis was virtually eliminated by minimizing contact time between the acidic reagents and the sample. Negative results were obtained when concentrated solutions of sodium tripolyphosphate were analyzed by this technique, however in the reactive phosphate technique of Strickland and Parsons (20)—a widely used oceanographic method—considerable hydrolysis of the polyphosphate took place. 

Industrial water analysis. A distinction can be made between boiler feed water analysis, boiler water analysis and analysis of condensate. In addition to measuring pH, oxidation reduction potential and electrical conductivity, these three types of analysis also require the determination of traces of oxygen and carbon dioxide, but also quantitative analyses, e.g. for iron and manganese, copper, nitrogen compounds, "water hardness" and chloride, sulphate, phosphate and silicic acid. 

Figure 10.184 Analysis of condensed phos- volume 50 pL sample 0.1% washing powder phates in a detergent. Separator column Ion- solution peaks (1) orthophosphate, (2) pyro-Pac AS7 eluent 0.07 mol/L HNO3 flow rate phosphate, (3) sulfate, and (4)...

Phosphate-polymer control, in industrial water treatment, 26 132-133 Phosphate recognition, 16 794 Phosphate refractory dental dies, compressive strength, 8 289t Phosphate rock, 11 119, 120 minerals in, 19 5, 14 recovery of fluoride from, 14 12-13 U.S. imports for consumption of, 19 15t U.S. production of, 19 17 Phosphates, 18 814-863 19 19. See also Phosphate Polyphosphates aluminum acid, 18 839 ammonium, 11 487 18 835-836 analysis of, 18 851-852 calcium, 18 836-839 condensed, 18 841-852 crystalline, 18 839 dispersants, 8 710t economic aspects of, 18 859-860... 

Since the labeling technique was introduced, a large number of further publications on the paper chromatography of phosphates have appeared (159), but these papers will not be considered separately here. They serve to confirm what was already partly known, and they describe improvements in technique, thereby reducing the risk of hydrolysis of the condensed phosphates in the acid medium used in chromatography. They also show how the accuracy of quantitative analysis could be increased (226). 

Hyperammonemia has occurred during parenteral nutrition as a component of therapy for renal insufficiency (905). The hyperammonemia presented as a change in mental status, developing about 3 weeks after initiation of parenteral nutrition therapy in most cases the episodes are of increasing duration and paroxysmal. In three of the patients, serum amino acid analysis in the acute phase showed reduced concentrations of ornithine and citrulline (the respective substrate and product of condensation with carbamyl phosphate at its entry into the urea cycle). Concentrations of arginine, the precursor to ornithine, were raised. 

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