a simple, rapid and sensitive spectrophotometric method has been proposed for the determinationof vanadium (iv). the method is based on the catalytic effect of v (iv) on the oxidation of alkali blue bypotassium bromate at ph 4. the rate of decrease in the absorbance of alkali blue (at 572 nm) wasproportional to the concentration of v (iv) in the range of 100-6000 ng ml-1. the detection limit wa...

A sensitive and simultaneous spectrophotometric flow injection method for the determination of vanadium(IV) and vanadium(V) is proposed. The method is based on the effect of ligands such as 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) and diphosphate on the conditional redox potential of iron(III)/iron(II) system. A four-channel flow system is assembled. In this flow system, diluted hydrochloric...

The preparation of highly pure vanadyl sulfate from sulfate solutions containing impurities of iron and aluminumwas investigated by solvent extraction with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA) and tri-n-butyl phosphate (TBP) as the phase modifier. The extraction and stripping conditions of vanadium (IV) and its separation from iron and aluminum were optimized. Under the...

The aims of this study were to clarify the effects of high vanadium on the renal cell cycle and apoptosis in broilers. 420 one-day-old avian broilers were divided into six groups and fed on a control diet (vanadium 0.073 mg/kg), and five high vanadium diets (vanadium 5 mg/kg, high vanadium group I; 15 mg/kg, high vanadium group II; 30 mg/kg, high vanadium group III; 45 mg/kg, high vanadium grou...

The vanadium-vanadium interactions in the polygonal aggregates of d¹ vanadium(IV) atoms, with a total of 4k + 2 vanadium electrons (k an integer) imbedded in an electronically inactive borate matrix in certain vanadoborate structures are analogous to the ring carbon-carbon interactions in diamagnetic planar cyclic hydrocarbons. They thus represent a high-spin analogue of aromaticity. Thus, the ...

Vanadium (III) gives a greenish- yellow complex with anthranilic acid in presence of pyridine. The complex is extractable with chloroform and is used for photometric determination of vanadium by measuring the absorbance at 390 nm against a reagent blank. Beer's Law holds good in the range of 1-20 pg V/ml. Moderate amounts of Pb (II) , Ca (II) , Sr (II) , Ba (II) , Cd (II) , Mg (II) , Mn (II...

The ubiquity of vanadium oxo complexes in the V+ and IV+ oxidation states has contributed to a comprehensive understanding of their electronic structure and reactivity. However, despite being predicted to be stable by ligand-field theory, the isolation and characterization of a well-defined terminal mononuclear vanadium(III) oxo complex has remained elusive. We present the synthesis and charact...

The magnetic properties of intact and freeze-dried blood cells of the tunicate Ascidia nigra and of model vanadium(III) and (IV) compounds as polycrystalline solids and in aqueous solution have been measured up to 50 kOe with a SQUID susceptometer. Corrections for the samples' diamagnetism were extracted from the temperature dependence of the data without any further assumptions. For vanadium(I...

the possibility of application of 4-nitrocatechol (4-nc) - tetrazolium salt - organic solventsystems for liquid-liquid extraction-spectrophotometric vanadium (iv and v) speciation wasstudied. six commercially available tetrazolium salts (2,3,5-triphenyltetrazolium chloride (ttc),3-(2-naphtyl)-2,5-diphenyltetrazolium chloride (tetrazolium violet, tv); 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetra...

The possibility of application of 4-nitrocatechol (4-NC) - tetrazolium salt - organic solventsystems for liquid-liquid extraction-spectrophotometric vanadium (IV and V) speciation wasstudied. Six commercially available tetrazolium salts (2,3,5-triphenyltetrazolium chloride (TTC),3-(2-naphtyl)-2,5-diphenyltetrazolium chloride (Tetrazolium Violet, TV); 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetra...