Ammonium molybdates phosphate

In the presence of ammonium metavanadate and acidic ammonium molybdate, phosphate forms vanadomolybdophosphoric acid. The absorbance of this yellow-colored product is commonly measured at 470 run. The sensitivity is generally lesser than that for reduced PMB methods, but it is quite tolerant of interfering ions, and is suitable for monitoring FRP in waste and contaminated waters. A detection limit of 200 pg P (6.5 pM) using a 1 cm cuvette has been reported for this method [25]. 

In an alternative industrial process, resorcinol [108-46-3] is autoclaved with ammonia for 2—6 h at 200—230°C under a pressurized nitrogen atmosphere, 2.2—3.5 MPa (22—35 atm). Diammonium phosphate, ammonium molybdate, ammonium sulfite, or arsenic pentoxide maybe used as a catalyst to give yields of 60—94% with 85—90% selectivity for 3-aminophenol (67,68). A vapor-phase system operating at 320°C using a siUcon dioxide catalyst impregnated with gallium sesquioxide gives a 26—31% conversion of resorcinol with a 96—99% selectivity for 3-aminophenol (69). 

Phosphate. Phosphoms occurs in water primarily as a result of natural weathering, municipal sewage, and agricultural mnoff The most common form in water is the phosphate ion. A sample containing phosphate can react with ammonium molybdate to form molybdophosphoric acid (H2P(Mo202q)4). This compound is reduced with stannous chloride in sulfuric acid to form a colored molybdenum-blue complex, which can be measured colorimetrically. SiUca and arsenic are the chief interferences. 

AMMO 2.5 EC , cypermetlu-in, 13 Ammonia, 13 Ammonium acetate, 13 Ammonium arsenate, 13 Ammonium benzoate, 13 Ammonium bicarbonate, 13 Ammonium bifluoride, 14 Ammonium bisulfite, 14 Ammonium carbamate, 14 Ammonium carbonate, 14 Ammonium chloride, 14 Ammonium chlorplatmate, 14 Ammonium clu omate, 14 Ammonium citrate, 14 Ammonium diclu omate, 14 Ammonium fluoride, 14 Ammonium fomiate, 15 Ammonium hexafluorosilicate, 15 Ammonium hydroxide, 15 Ammonium metavanadate, 15 Ammonium molybdate, 15 Ammonium nitrate, 15 Ammonium oxalate, 15 Ammonium perfluorooctanoate, 15 Ammonium persulfate, 15 Ammonium phosphate, 15 Ammonium picrate, 16 Ammonium salicylate, 16... 

Determination of phosphate as ammonium molybdophosphate. This may be readily effected by precipitation with excess of ammonium molybdate in warm nitric acid solution arsenic, vanadium, titanium, zirconium, silica and excessive amounts of ammonium salts interfere. The yellow precipitate obtained may be weighed as either ammonium molybdophosphate, (NH4)3[PMo12O40], after drying at 200-400 °C, or as P205,24Mo03, after heating at 800-825 °C for about 30 minutes. 

Molybdenum blue method. When arsenic, as arsenate, is treated with ammonium molybdate solution and the resulting heteropolymolybdoarsenate (arseno-molybdate) is reduced with hydrazinium sulphate or with tin(II) chloride, a blue soluble complex molybdenum blue is formed. The constitution is uncertain, but it is evident that the molybdenum is present in a lower oxidation state. The stable blue colour has a maximum absorption at about 840 nm and shows no appreciable change in 24 hours. Various techniques for carrying out the determination are available, but only one can be given here. Phosphate reacts in the same manner as arsenate (and with about the same sensitivity) and must be absent. 

B. Phosphovanadomolybdate method Discussion. This second method is considered to be slightly less sensitive than the previous molybdenum blue method, but it has been particularly useful for phosphorus determinations carried out by means of the Schoniger oxygen flask method (Section 3.31). The phosphovanadomolybdate complex formed between the phosphate, ammonium vanadate, and ammonium molybdate is bright yellow in colour and its absorbance can be measured between 460 and 480 nm. 

Sodium ammonium hydrogenphosphate Ammonium hydrogensulphride Anunonium sdlphamate Hydrazine sulphate Ammonium phosphate Diammonium sulphite Ammonium thiosulphate Ammonium molybdate Amnwnium sulphate Diammonium peroxodlsutphate... 

Because the preceding chromogenic assay rely on choline quantitation, the hydrolysis of substrates with headgroups other than choline cannot be followed. To circumvent this problem, another useful protocol was devised whereby the phosphorylated headgroup produced by the PLCBc hydrolysis is treated with APase, and the inorganic phosphate (Pi) that is thus generated is quantitated by the formation of a blue complex with ammonium molybdate/ascorbic acid 5 nmol of phosphate may be easily detected. This assay, which may also be performed in a 96-well format, has been utilized to determine the kinetic parameters for the hydrolysis of a number of substrates by PLCBc [37,38]. 

The simple colorimetric method is based on that originally published by Murphy and Riley (1962). Phosphates are colorless or pale in solution, so the phosphorus in the test solution is quantitatively converted to a colored compound, firstly using an acidic molybdate solution (ammonium molybdate in nitric acid) ... 

Olsen et al. [62] have described a method for the determination of pH8.5 sodium bicarbonate extractable phosphorus in soils. The concentration of the blue complex produced by the reduction, with ascorbic acid, of the phosphomolybdate formed when acid ammonium molybdate reacts with phosphate is measured spectrophotometrically at 880 nm [63]. 

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. 

A small portion of the hydrolysis solution was strongly acidified with concentrated nitric acid, and warm ammonium molybdate solution added. No visible change took place, and it was only after some minutes boiling that a yellow coloration was produced. This is good evidence against equation (c). Presumably sodium di-isopropyl phosphate requires to be broken down with boiling nitric acid before phosphoric acid is produced. 

The ester group is then hydrolysed, and the hydrolysis normally stops at the MePO(OH)2 stage. More vigorous conditions are required to rupture the Me—P bond. Thus the normal hydrolysis product of D.F.P. and of tabun, namely, phosphoric acid, will give a positive test with ammonium molybdate, whereas the product from sarin, namely, methylphosphonic acid, will not respond to this test. Vigorous reagents such as hot nitric acid and ammonium persulphate will break the C—P link and then a positive test for phosphate is obtained with ammonium molybdate. Sarin can be prepared in a variety of ways. Three... 

Column (10) Indicates that volatile material Is aspirated into the huhhler C containing a 10 per cent aqueous solution ot ammonium molybdate mixed with an equal volume of benzidine solution (made by dissolving 0 05 g. of benzidine in 10 ml. of glacial acetic acid and making up to 100 ml. with water). D.F.P. and tabun are hydrolysed to phosphate and a typical green or green-blue coloration is produced.1... 

The limit test for phosphate is based upon the formation of ayellow colour reaction with molybdovanadic reagent (combination of ammonium vanadate and ammonium molybdate) in an acidic medium. However, the exact composition of the molybdovanadophosphoric acid complex is yet to be established. 

Triclofos Sodium Dissolve 25 mg in 10 ml of DW, add 4 ml of 1 M H2S04, 1 ml of a 10% w/v soln. of ammonium molybdate and 2 ml of a methylaminophenol-sulphite soln. and allow to stand for 15 minutes. Add sufficient DW to produce 25 ml, allow to stand for a further 15 minutes and measure the absorbance of a 4 cm layer of the resulting soln. at 730 nm. Calculate the content of Phosphate from a calibration curve prepared by treating suitable vols. of a 0.00143% w/v soln. of KH2P04 in the same manner. NMT 1.0% calculated as po43-. 

Procedure (determination of inorganic phosphate (a) in the acetic acid extract). The 8-hydroxyquinoline forms a precipitate in acidic ammonium molybdate solution, which will interfere unless the aliquot is <5 ml. It should therefore be removed by ignition as follows. Transfer 10 ml acetic acid extract to a 45-ml silica basin, add 0.5 ml 1 M magnesium acetate and evaporate to dryness on a water-bath. (Note do not use magnesium nitrate, which reacts adversely on heating with 8-hydroxyquinoline.)... 

Ammonium molybdates are used to prepare high purity grade molybdenum metal powder, sheet, or wire for colorimetric analysis of phosphates and arse-... 

Ammonium Formate Ammonium Hydrosulfide Ammonium Molybdate Ammonium Nitrate Ammonium Phosphate, Dibasic Ammonium Phosphate, Monobasic. .. Barium Hydroxide Ammonium Phosphate, Monobasic Ammonium Sulfate Ammonium Sulfide Ammonium Thiocyanate Ammonium Thiosulfate Antimony... 

To prepare molybdenum liquid for determining the phosphate ion, dissolve 50 g of ammonium sulphate in 450 ml of a 68% nitric acid solution and 150 g of ammonium molybdate in 400 ml of distilled water. Cool the second solution to room temperature and pour it into the first one with constant stirring. Bring the total volume of the solution up to one litre. In a few days, filter off the solution for the precipitate. 

Phosphates. —10 gm. of ammonium molybdate with 25 cc. of water and 15 cc. of ammonia water (sp. gr. 0.910) should afford a clear solution. Add this solution to 150 cc. of nitric acid (sp. gr. 1.20 ). No yellow precipitate should form on standing two hours at a temperature of about 40° C. 

Phosphates. — Dissolve 2 gm. of sodium bicarbonate in 20 cc. of water, add 20 cc. of nitric acid and 10 cc. of ammonium molybdate solution. On heating to 30 to 40° C., no yellow precipitate should form within two hours. 

Phosphates. — To the solution of 20 gm. of sodium carbonate in 50 cc. of nitric acid add 50 cc. of a solution of ammonium molybdate in nitric acid. No yellow precipitate should form in the liquid on standing two to three hours at about 40° C. 

Ammonium molybdate, when added in considerable excess to a boiling solution of an arsenate in nitric acid, gives a yellow crystalline precipitate of ammonium 12-molybdo-arsenate, (NH4)3H4[As(Mo207)6]. 4H20 (see p. 215). Like the corresponding molybdo-phosphate, the precipitate is readily soluble in ammonia or aqueous alkali. The arsenate may be detected in the presence of phosphate by boiling the yellow precipitate with aqueous ammonium acetate until clear a white precipitate or turbidity on cooling shows the presence of arsenate, and the filtrate may be tested for phosphate.1... 

If a drop of 0-02N aqueous sodium sulphide is added to a drop of a solution containing arsenate or phosphate on a filter paper and a drop of aqueous ammonium molybdate acidified with sulphuric acid also added, a blue colour develops 2 ferro- and ferri-cyanides and thiocyanate should be absent. The formation of molybdenum blue is used in the colorimetric estimation of arsenic (see p. 321). 

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