Separation of Condensed Phosphates

Axtrenge et al. [1] have separated both linear and cyclic condensed phosphates on cellulose layers. The best separation of linear pol3q hos- 

Detection was carried out with the help of the molybdophosphate reaction with subsequent reduction to molybdenum blue using HgS. 

A mixture containing cyclic as well as the linear condensed polyphosphates can be successfully separated in a two-dimensional chromatogram (Fig. 237). In this, the acid solvent (MD2), mentioned above, is employed in the first direction after drying, the basic solvent AD 2, 

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Fig. 236. Separation of condensed phosphates on a cellulose layer. Detailed information is in the text (Rossel [20])...

Figure 3.158 Separation of condensed phosphates with a capacity gradient.

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... 

D. J. Halliwell, I. D. McKelvie, B. T. Hart and R. H. Dunhill (1996). Separation and detection of condensed phosphates in waste waters by ion chromatography coupled with flow injection. 

T. L. Wang and S. F. Y. Li (1998). Separation of synthetic inorganic polymers of condensed phosphates by capillary gel electrophoresis with indirect photometric detection. J. Chromatog. A, 802, 159-165. 

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.

Figure 3 (A) Ion-exchange chromatography-FIA system for separation of polyphosphates. (B) Optimized separation of orthophosphate (50 pgPI diphosphate (SOpgPr ), and triphosphate (SOngPI ) with an injection volume of 500 iit. (Halliwell DJ, McKelvie ID, Hart BT, and Dunhill RH (1996) Separation and detection of condensed phosphates in waste waters by ion chromatography coupled with flow injection. Analyst (Cambridge, UK) 121 1089-1093 reproduced by permission of The Royal Society of Chemistry.)...

Anion exchange chromatography and ion exchange chromatography have been used extensively for the separation and quantitation of condensed phosphates. Because phosphate is a poor UV chro-mophore, direct UV detection cannot be used, and fraction collection for subsequent acid hydrolysis and detection as molybdate reactive phosphorus (MRP)... 

It was observed that organically bound phosphorus is completely decomposed to phosphate when oxidized with persulphate in an alkaline medium. Furthermore, more than 60 % of condensed phosphates are hydrolyzed. As concentrations of polyphosphates are negligible in most natural waters, a simultaneous oxidation procedure for organic phosphorus and nitrogen compounds has been developed by Korolejf (1977). Valderrama (1981) compared the procedure with former methods using separate determinations. In the simultaneous oxidation, the pH of the reaction starts at ca. 9.7 and ends at 4-5. These conditions are obtained by a boric acid-NaOH system. In seawater samples no precipitation is formed when the oxidation mixture is added. At elevated temperatures a precipitation is formed, which, however, dissolves as oxidation proceeds. 

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). 

Highly condensed polyphosphates, which cannot be separated by paper chromatography may be separated into groups by paper electrophoresis 255). Paper chromatography allows the complete separation and quantitative determination of all condensed phosphates with n up to 10, but its use is limited to 7-quantities. 

Condensed phosphates containing three- atoms of phosphorus are tripolyphosphates, the most important of which is sodium tripolyphosphate (.STPP). This compound reacts with the protein in meat, fish, and poultry to prevent denaturing or loss of fluids. This properly is sometimes called "moisture binding. STPP also solubilizes protein, which aids in binding diced cured meat, fish, and poultry. It also emulsifies fat to prevent separation. 

Orthophosphate and condensed phosphate are a measure of inorganic phosphoms. The latter is also termed as acid-hydrolyzable phosphate. However, during mild acid hydrolysis, a small amount of phosphoms from organic phosphoms compounds may be released. To determine suspended and dissolved forms of phosphoms, the sample should be filtered through a 0.45 pm membrane filter, and the filtrate and the residue analyzed separately. 

Aflatoxin B leads to condensation of nuclei, separation of nuclei from the cytoplasm, cytoplasmic vacuolization, and loss of the brush border in MDBK (Madin-Darby bovine kidney) and PFBK cells (primary fetal bovine kidney) evidenced by electron microscopic examination [241]. In addition exposure of OK cells to Aflatoxin B resulted in an inhibition of inorganic phosphate uptake, which could not be abolished by application of parathyroid hormone (PTH) and insulin [221]. 

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