Solid-phase spectrophotometry has been applied to analysis for trace amounts of vanadium. Vanadium was sorbed in a styrene-divinylbenzene-type anion-exchanger Dowex 1-X8 as a vanadium-4-(2-pyridylazo)resorcinol complex. Resin phase absorbances at 562 and 800 nm were measured directly which allowed the determination of vanadium in the range of 0.1-2.4 ng/ml with a RSD of 1.5%. The method has bee...

This study describes a new simple, sensitive and selective catalytic kinetic spectrophotometricmethod for the determination of vanadium (V). The method is based upon the catalytic effect ofvanadium (V) on the oxidation of Carminic acid by bromate in sulfuric acid media. The reaction wasfollowed spectrophotometrically by measuring the decrease in absorbance at 490 nm and thedependence of sensiti...

this study describes a new simple, sensitive and selective catalytic kinetic spectrophotometricmethod for the determination of vanadium (v). the method is based upon the catalytic effect ofvanadium (v) on the oxidation of carminic acid by bromate in sulfuric acid media. the reaction wasfollowed spectrophotometrically by measuring the decrease in absorbance at 490 nm and thedependence of sensiti...

A simple and sensitive kinetic-spectrophotometric method is described for the determination of vanadium and the possible mechanism of catalytic reaction is proposed. The method is based on the vanadium(V)-catalyzed oxidation of 1,8-diaminonaphthalene (DNA) by potassium bromate (Tiron as activator) at pH 3.8 and 40 degrees C. The reaction was monitored spectrophotometrically by measuring the inc...

A chronoamperometric method for vanadium ion determination, based on the inhibition of the enzyme alkaline phosphatase, is reported. Screen-printed carbon electrodes modified with gold nanoparticles were used as transducers for the immobilization of the enzyme. The enzymatic activity over 4-nitrophenyl phosphate sodium salt is affected by vanadium ions, which results in a decrease in the chrono...

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...

A solvent-extraction spectrophotometric technique is proposed as a new method for determination of trace quantities of vanadium. Sodium salt of 2-mercapto-pyridine-N-oxide (thione) forms a complex with vanadium instantaneously. The purple 1:2 complex is formed of pH 2.3, easily extracted in chloroform and shows strong absorbance at 500 nm. The extracted complex is found to obey Beer's law 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...

Chemiluminescence from the vanadium and potassium permanganate reaction was studied under acidic conditions to develop a sensitive method for vanadium determination using the formaldehyde enhancement effect. The method was successfully applied to the determination of vanadium in seawater. Experimental parameters were optimized, including acid concentration, potassium permanganate and formaldehy...

We describe a sensitive method for the determination of vanadium in biological substances by atomic absorption spectroscopy. By using background correction and pyrolytically coated graphite tubes with flameless apparatus, this vanadium assay has a sensitivity of 65 pg and a detection limit of 30 pg, approximately sixfold more sensitive than previously reported assays involving this technique. T...