a simple and rapid method has been developed for the determination of ascorbic acid in fruit and pharmaceutical products. the method is based on the measurement of the reaction rate between ammonium molybdate and ascorbic acid in acidic media. the reaction was monitored spectrophotometrically at 800 nm by fixed-time and variable-time methods. the calibration graph was linear in the range of 5 0...

molybdate sulfuric acid (msa) has been prepared and used as catalyst for the biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. the catalyst loading is low and it shows recyclability. this method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.

The hierarchical assembly of DSCs containing a new heteroleptic copper(I) complex with a phosphonic acid anchoring ligand is described; it is shown that conventional I(-)/I3(-) electrolytes may be replaced by [Co(bpy)3](2+/3+) with no loss in performance.

The simultaneous spectrophotometric determination of phosphate and silicate ions in river water was examined by using ion-exclusion chromatography and post-column derivatization. Phosphate and silicate ions were separated by the ion-exclusion column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the H(+)-form (TSKgel Super IC-A/C) by using ultra pure water as an elu...

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum-blue complex (under heating) increases by elevating the ammonium molybdate concentra­ tion, and at a ratio of molybdate molarity/acid normality equal to 10, there is maximum color development at any acid normality in the range 1—4 n with either HC104 or H2S04 (or their mixtures). On the basis of these f...

A 1,10-phenanthroline (phen) chelated molybdenum(VI) citrate, [(MoO2)2O(H2cit)(phen)(H2O)2] x H2O (1) (H4cit = citric acid), is isolated from the reaction of citric acid, ammonium molybdate and phen in acidic media (pH 0.5-1.0). A citrato oxomolybdenum(V) complex, [(MoO)2O(H2cit)2(bpy)2] x 4H2O (2), is synthesized by the reduction of citrato molybdate with hydrazine hydrochloride in the presenc...

In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capab...

3-Phosphoglycerate phosphatase from sugarcane leaves (Saccharum) was purified 2530-fold to a specific activity of 740. The molecular weight was estimated to be about 160,000 by sucrose density gradient centrifugation. During electrophoresis with sodium dodecyl sulfate the protein divided into three or four subunits. The phosphatase was unstable above pH 7.5 but very stable from pH 4.5 to 6.5 at...

The great instability of creatine phosphate (Fiske & Subbarow, 1929), acetyl phosphate (Lipmann & Tuttle, 1944) and 1:3-diphosphoglyceric acid (Negelein & Bromel, 1939) in solutions containing molybdate has been known almost as long as these compounds themselves. It could not fail to attract the attention of the analyst who used a method of phosphate estimation ofthe Briggs (1922) or Fiske & Su...