Potassium phosphomolybdate

EXERCISE 63. POTASSIUM PHOSPHOMOLYBDATE, 2K20-P206-24Mo03-4H20... 

This ammonium phosphomolybdate complex is yellow, but if mildly reduced by ascorbic acid in the presence of potassium antimonyl tartrate a solution of stable bluish-purple color ( molybdenum blue ) develops after about ten minutes, which has its strongest absorption at 882 pm (Fig. 4.6). Other mild reducing agents have also been used, including tin(II) chloride, or hydrazine sulfate, which give maximum absorbances at slightly different wavelengths. The intensity of the color which develops is linearly proportional to the... 

Phosphomolybdic acid-Potassium dichromate-Copper(II) sulfate. 

Phosphomolybdic acid-Potassium di-chromate-Copper(II) sulfate, 248 of nitrogen compounds other than amines... 

Phosphomolybdic acid-Potassium di-chromate-Copper(II) sulfate, 248 Tin(II) trifluoromethanesulfonate, 301 Other unsaturated carbonyl compounds Lead tetraacetate, 155 Pyrylium perchlorate, 263 Zinc-copper couple, 348 a-Substituted-a, p-unsaturated carbonyl compounds... 

Tin(II) chloride reduces not only the reactive phosphomolybdic acid but also its relatively unreactive (e.g. ammonium or potassium) salts to molybdenum blue . However, antimony(III) salts do not reduce ammonium phos-phomolybdate Sn2+ may thus be detected in the presence of Sb3+. 

Annapurna et al. [13] established simple, accurate, and reproducible UV spectrophotometric methods for fhe assay of buclizine based on the formation of precipitation, charge transfer, and redox products. Precipitation/ charge transfer complex formation of fhe buclizine with I2/p-nitro methyl amino phenol sulfate-sulfanilic acid by method A, the precipitation/complex formation with ammonium molybdate/potassium thiocyanate by method B and precipitation/redox reaction of buclizine with phosphomolybdic acid/Co /EDTA by method C were proposed. Determination of buclizine in bulk form and in pharmaceutical formulations was also incorporated. 

General Reactions of Alkaloids (Section 670).—Dissolve the amount of quinine sulphate that can be held on the point of a pen-knife in about 20 cc. of water. Observe the appearance of the solution. Add to 2 cc. of the solution drop by drop, a dilute (1 per cent) solution of tannic acid. Repeat using solutions of phosphomolybdic acid, picric acid, iodine in potassium iodide, and potassium mercuric iodide. The last-named solution can be prepared by adding an excess of a solution of potassium iodide to a solution of mercuric chloride. 

The copper number of paper may be obtained using copper(II) solution, some of which is reduced to Cu(I) oxide as the carbonyl groups are oxidised to carboxylic acid. There are several variants of the test, one of which involves treating the produced Cu(I) oxide with phosphomolybdic acid. The reduced molybdenum is then titrated with potassium permanganate. 

II. The albuminoids are precipitated in an insoluble form by 1, the concentrated mineral acids, notably HNOs 2, by potassium ferrocyanid in presence of acetic acid 3, by certain organic acids in the presence of cpncentrated solutions of NaCl or Na SO< 4, by tannin in acid solution 5, by phosphomolybdic or phospho-tungstic acid 0, by double lodid of potassium and mercury, or double iodid of potassium and bismuth, in acid solution 7, by solutions of the salts of Pb, Cu, Ag, Hg, U 8, by chloral, picric acid, phenol or trichloracetic acid. 

III. The Ordinary Alkaloidal Reagents,—The reagents which precipitate alkaloids from their solutions react also with proteins. Among these may be mentioned phosphotungstic acid, phosphomolybdic acid, tannic acid, picric acid, potassium mercuric iodide, and potassium bismuth iodide. The alkaloidal reagents precipitate the majority of the proteins in acid solution only. 

Phosphorus is analyzed by atomic absorption and ICP emission spectrometry and neutron activation techniques. The total phosphorus contents can be estimated colorimetrically by classical wet methods (American Public Health Association... 1995). Phosphorus is oxidized to orthophosphate by digesting with potassium persulfate. The solution is treated with ammonium molybdate and antimony potassium tartarate in an acid medium to form an antimony-phosphomolybdate complex that is reduced by ascorbic acid to form a deep blue coloration, the intensity of which is proportional to the concentration of phosphorus. The absorbance is measmed at 650 nm by a spectrophotometer. Alternatively, it can be analyzed colorimetrically by an autoanalyzer (Technicon model). 

White precipitates are formed when a 1% solution of cusparine is treated with phosphotungstic, phosphomolybdic or tannic acids, or with mercuric chloride or potassium mercuri-iodide. Picric acid, platinic chloride or potassium chromate give yellow precipitates, auric chloride or potassium bismuth iodide brown, and potassium ferrocyanide bluish-white (36). By treating a solution of cusparine hydrobromide with bromine water, a series of bromocusparine polybromides is obtiuned(38). 

Although it contains two nitrogen atoms, vasicine is a monoacidic base numerous salts have been described (see Section 5). It forms precipitates with phosphotungstic, phosphomolybdic, picric and picro-Ionic acids, platinic, auric and mercuric chlorides, potassium mercuric... 

Perchloric acid Phosphomolybdic acid Phosphorus oxychloride Phosphorus pentachloride Phosphorus trichloride y-Picoline Polyphosphoric acid Potassium silicate Rhodium Selenium Selenium dioxide Silica gel Silver oxide (ous) Sodium borohydride Sodium silicate Strontium carbonate Sulfur dioxide Tantalum Tellurium Tetraisopropyl di (dioctylphosphito) titanate Titanocene dichloride Trichloromethylphosphonic acid Tristriphenylphosphine rhodium carbonyl hydride Tungsten carbide Vermiculite Ytterbium oxide Zinc chloride Zinc dust Zinc 2-ethylhexanoate Zirconium potassium hexafluoride... 

Ammonium thiosulfate Copper chloride (ic) Phosphomolybdic acid Phosphotungstic acid Potassium ferricyanide Sodium ferrocyanide Sodium silicomolybdate Sodium thiosulfate anhydrous Sodium thiosulfate pentahydrate fixative, photographic developer Sodium sulfite... 

In addition to the iodometiic determination, direct precipitation as barium sulfate before and after treatment with bromine was suggested for both quantitative and qualitative test for sulfur dioxide in wine (see Monier-Williams, 1927). Precipitation of SO2 after oxidation with H2O1 as the benzidine sulfate was proposed by Rothen-fusser (1929) reduction of the molybdenum in phosphomolybdic acid by the sulfite ion present in an aqueous solution of the food was proposed by Sasaki (1928) as a colorimetric method formation of a blue color from a solution of 1% methylene blue and 5% iodine in potassium iodide was proposed by Svershkov (1939). Mathers (1949) proposed a turbidimetric method based on the distillation of wine into a dilute solution of lead acetate to form a colloidal suspension of lead sulfite whose spectral transmittance in the range of 400 to 700 mn could be used as a measure of sulfur dioxide. This is similar to turbidimetric methods based on turbidity produced by adding BaCfii to a... 

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