Total insoluble phosphorus

Copper and iron which may be released into solution by the digestion of suspended sediment material in the analysis of total insoluble phosphorus, did not interfere in concentrations (200 fig. Cu and 3 mg. Fe Vsample) several times greater than those found in typical San Francisco Bay sediments. 

The results of the preservation study (Figure 2) show that for long periods (one month) the best preservation technique was storage at —10°C. with 40 mg. Hg Vliter. For storage periods of a few days, any of the methods, except storage at 4°C. with CHCI3, were satisfactory. The chloroform treatment produced a dramatic reduction in soluble orthophosphate and an accompanying rise in total insoluble phosphorus. 

Vandercook and Guerrero (150) characterized orange juices by fractionating the total phosphorus content (19.3 + 2.5 mg P/100 ml) into lipid (1.4 +0.3), inorganic (12.6 +2.9), and ethanol-insoluble (3.0 + 0.8) phosphorus. A limited number of grapefruit and lemon juices were also characterized. 

If a water sample contains both soluble and insoluble manganese (Mn) compounds and ions, and it is filtered to separate the dissolved and insoluble fractions, and the filtrate and insoluble residue are analyzed separately, the results can be expressed as total dissolved Mn and total suspended or insoluble Mn. Phosphorus (P) can be determined colorimet-rically as the ortho-phosphate ion, P043, in aqueous samples after a reaction that forms an intensely blue-colored derivative. However polyphosphate ions and other ions and compounds containing P do not form this derivative. Total P in a sample can be determined with the same colorimetric procedure after acid hydrolysis and oxidation of all ions and compounds containing P to P04 3. In some elemental analyses the sample is treated with reagents designed to make available for measurement some fraction of an element or elements but not the total amount. For example, a soil sample may be treated with water at pH 3 to simulate the leaching process of acid rain. A total elemental analysis of the filtrate provides information about just those elements solubilized by the mild acid treatment. This can be called the determination of total mild acid leachable elements. 

Approximately 70f of the monoferric phytate baked into bread could be recovered in extracts of the bread. He have not tested the bioavailability or the chemical form of iron when an iron salt and sodium phytate are baked into bread as was done by McCance et al. (3). If an insoluble ferric phytate of any ion composition was formed, we would expect the iron to be poorly bioavailable. Hussain and Patwardhan (22) did not specify whether they added sodium phytate to the food during preparation or administered it orally when young men ate the meals in their study using a vegetarian menu. They found decreased iron balance when the percentage of phytate phosphorus to total phosphorus was increased from 8 to 40 by addition of sodium phytate. 

In 1934, Blackwood and Wishart studied the action of pepsin and trypsin on vitellin (11). According to these workers pepsin splits the protein into a phosphorus-poor and a phosphorus-rich fraction. The acid-insoluble portion with 73 % of the total phosphorus and a ratio of P/N of 3.65 was resistant to further action of the enzyme. 

There are also organic phosphates, and all of these forms can be either dissolved or particulate (i.e., insoluble). The sum of all the forms is known as total phosphorus. 

The deactivated catalyst was studied by several methods scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS), infrared spectroscopy (IR), and by extracting water-insoluble phosphorus. The SEM-EDS studies gave no useful results. IR absorption was measured on samples that were mulled in mineral oil. Comparisons of IR spectra were made with samples of y -alumina and aluminum phosphate. Determination of total P in the deactivated sample, presumed to be present as water-insoluble aluminum phosphate, was made by standard wet chemical analysis dissolution in hot, dilute HCl followed by colorimetric determination of phosphate. ... 

In soil, phytic acid forms insoluble complexes with Ca, Fe and Al, and since these complexes are reasonably stable, they tend to accumulate. In some localities the phytic acid content can reach as much as 50% of the total organic phosphorus which is present. 

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