Phosphate contaminants

Confirmation by GC/MS is recommended. Recovery is acceptable (82%). Tributyl phosphate and triphenyl phosphate contamination was reported in procedural blanks and may prevent determination of phosphate esters at levels near the detection limit (1 ng/g) (LeBel and Williams 1983 1986). 

Note In this experiment, the phosphorus in water samples is determined by visible spectrometry following a reaction of the phosphates in the sample with potassium antimonyl tartrate, ammonium molybdate, and ascorbic acid. All glassware should be washed in phosphate-free detergent prior to use to avoid phosphate contamination. 

In conclusion, it should be noted that we live in an environment with a permanent phosphorus excess. This factor, resulting from the wide use of phosphate-containing detergents, fertilizers and food additives may have some negative effects on the environment and human health. The biochemistry of PolyPs may offer new ways for overcoming unfavourable factors caused by phosphate contamination of the environment and for controlling infections and some other diseases. 

The solution reached predicts that phosphate should move no deeper than 1 meter after ten years, and the shallow well is at no immediate risk from phosphate contamination. Nitrate contamination of the well would, however, be likely because NO3 is a very mobile anion. 

Activated charcoal (free of P) or Dargo G-60 the activated charcoal is likely to contain traces of P which has to be removed by repeated washings with Olsen s reagent followed by warm distilled water. The material should test free of phosphorus when extracted with Olsen s reagent. The NaHCOg should also be tested from any phosphate contamination. 

The most likely source of phosphate contamination would be ATP, ADP, or the enzyme. ATP and ADP may be unstable and undergo hydrolysis in aqueous solution, over time. The enzyme stock buffer must not contain phosphate, excluding common buffer selections such as PBS. If necessary, test individual component of the assay at appropriately diluted assay-level concentrations in ColorLock reagents for phosphate contamination. Sec Note 1 for additional details. 

Clean Pyrex Erlenmeyer flasks have been found to give no phosphate contamination. Flasks should be retained especially for the present method, covered by aluminium foil, and not put into general circulation. Before their initial use, they should be cleaned by fuming after the addition of about 30 ml of water, 20 ml of concentrated hydrochloric acid, and 10 ml of perchloric acid solution. The perchloric acid is refluxed vigorously in each flask for about 1 hr. A blank determination (see Sect. G below) should then be carried out on each flask before it is finally put into use. The flasks are rinsed thoroughly with distilled water after each determination and stored dry. 

Although the process requires the addition of a phosphate donor, such as glycerol-2-phosphate, it may be a valuable tool for cleaning water contaminated with radionuchdes. An alternative mode of uranium precipitation is driven by sulfate-reducing bacteria such as Desulfovibrio desulfuricans which reduce U(VI) to insoluble U(IV). When combined with bicarbonate extraction of contaminated soil, this may provide an effective treatment for removing uranium from contaminated soil (85). 

S. cerevisiae is produced by fed-batch processes in which molasses supplemented with sources of nitrogen and phosphoms, such as ammonia, ammonium sulfate, ammonium phosphate, and phosphoric acid, are fed incrementally to meet nutritional requirements of the yeast during growth. Large (150 to 300 m ) total volume aerated fermentors provided with internal coils for cooling water are employed in these processes (5). Substrates and nutrients ate sterilized in a heat exchanger and then fed to a cleaned—sanitized fermentor to minimize contamination problems. 

Hydrogen Chloride as By-Product from Chemical Processes. Over 90% of the hydrogen chloride produced in the United States is a by-product from various chemical processes. The cmde HCl generated in these processes is generally contaminated with impurities such as unreacted chlorine, organics, chlorinated organics, and entrained catalyst particles. A wide variety of techniques are employed to treat these HCl streams to obtain either anhydrous HCl or hydrochloric acid. Some of the processes in which HCl is produced as a by-product are the manufacture of chlorofluorohydrocarbons, manufacture of aUphatic and aromatic hydrocarbons, production of high surface area siUca (qv), and the manufacture of phosphoric acid [7664-38-2] and esters of phosphoric acid (see Phosphoric acid and phosphates). 

Phosphatase Test. The phosphatase [9001-78-9] test is a chemical method for measuring the efficiency of pasteurization. AH raw milk contains phosphatase and the thermal resistance of this enzyme is greater than that of pathogens over the range of time and temperature of heat treatments recognized for proper pasteurization. Phosphatase tests are based on the principle that alkaline phosphatase is able, under proper conditions of temperature and pH, to Hberate phenol [108-95-2] from a disodium phenyl phosphate substrate. The amount of Hberated phenol, which is proportional to the amount of enzyme present, is determined by the reaction of Hberated phenol with 2,6-dichloroquinone chloroimide and colorimetric measurement of the indophenol blue formed. Under-pasteurization as well as contamination of a properly pasteurized product with raw milk can be detected by this test. 

Because monocalcium phosphate is incongmently soluble, it is typically contaminated with various amounts (6—10%) of dicalcium phosphate and free phosphoric acid resulting from in-process disproportionation of the monocalcium salt. Free phosphoric acid may render the product hygroscopic, and absorbed water plus acid catalyzes further decomposition to additional free acid and dicalcium phosphate. For this reason, industrial monocalcium phosphate may contain some dicalcium phosphate resulting from excess lime addition and then aged to ensure the removal of residual free phosphoric acid. 

Some producers beneficiate the phosphate ore prior to agglomeration to increase the phosphate content and remove undesirable contaminants. One approach uses a water wash to remove fines which are lower in assay and higher in contamination. If too much clay is removed from the ore by the beneficiation, a binder such as bentonite clay must be added back to the ore to faciUtate agglomeration. 

The need for acid concentrators exists because many uses of sulfuric acid do not lead to its consumption. Instead, the acid is diluted and partially degraded and contaminated. In the past, large amounts of acid were disposed of either by usiag it ia the phosphate fertilizer iadustry to dissolve phosphate rock or by neutralization and subsequent discharge to waterways. 

Scale and deposits are controlled through the use of phosphates, chelants, and polymers. Phosphates are precipitating treatments, and chelants are solubilizing treatments. Polymers are most widely used to disperse particulates but they are also used to solubilize contaminants under certain conditions. 

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