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 catalytic spectrophotometric method for determination of ultra-trace quantities of manganese(ii) id described. the method is based on the catalytic effect of manganese(ii) on the oxidation reaction of ferroin by potassium periodate in acidic media. the reaction is monitored spectrophotometrically at 510 nm by a slope method and mn(ii) is determinable in the range of 1-1000ngml-1. the limit of...

a simple, selective and sensitive method for the determination of trace amount of titanium (iv) based on its catalytic effect on methylene blue- ascorbic acid redox reaction has been reported. the reaction was followed spectrophotometrically by measuring the change in absorbance of methylene blue at 665 nm, 5 minutes after the initiation of the reaction. in this study experimental parameters we...

chromium(III) up to 100 ng mL−1, and for chromium(VI) up to 200 ng mL−1) were obtained, using the “fixed time” method with detection limits of 4.9 ng mL−1 and 3.8 ng mL−1, respectively. The results suggest that at the reaction conditions chromium(VI) is reduced and chromium(III) is oxidized to an intermediate oxidation state and the catalytic action of chromium is due to the formation of an act...

Anew, highly sensitive and selective catalytic kinetic method (CKM) for determination of osmium (VIII) has been established based on its catalytic effect on the oxidation of thionine dye by hydrogen peroxide in alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance band of thionine at 600 nm. Under the optimum conditions, the proposed ...

A catalytic spectrophotometric method for determination of ultra-trace quantities of manganese(II) id described. The method is based on the catalytic effect of manganese(II) on the oxidation reaction of ferroin by potassium periodate in acidic media. The reaction is monitored spectrophotometrically at 510 nm by a slope method and Mn(II) is determinable in the range of 1-1000ngmL-1</sup...

Unlike lactoperoxidase and horseradish peroxidase, thyroid peroxidase catalyzed the oxidation of hydroquinone mostly by way of 2-electron transfer. This conclusion could be derived from three independent experiments: ESR measurements of p-benzosemiquinone, trapping the unpaired electron by cytochrome c, and spectrophotometric analysis of catalytic intermediates of the enzymes. The 1-electron fl...

a simple, rapid and sensitive method has been developed for determination of trances of tellurium (vi) (0.096-1.250 mg/ml) based on its catalytic effect on the reduction reaction of toluidine blue by sulfide ion at ph 4. the reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 628 nm by the fixed time method. the detection limit is 80 ng/ml and...

A Simple, rapid and sensitive method has been developed for determination of trances of tellurium (VI) (0.096-1.250 mg/mL) based on its catalytic effect on the reduction reaction of toluidine blue by sulfide ion at pH 4. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 628 nm by the fixed time method. The detection...