a sensitive and selective procedure was developed for the spectrophotometric determination of silver by its catalytic effect on the oxidation of gallocyanine by peroxydisulphate in acidic media at 540 nm. silver can be determined in the range of 0.001-0.500 µg/ml with a limit of detection of 0.0005 µg/ml, by a fixed-time method of 4.0 min from initiation of the reaction, the relative standard d...

a new simple arid rapid catalytic kinetic method for determination of trace amounts of chromium (110 isdescribed. the method is based on the catalytic effect of chromium (iii) on the reduction of methylene blue byascorbic acid in acidic media. the reaction monitored smectrophotomenically by measuring the decrease ofabsorbance at 664 nm at 25 c. the fixed-time method was used for the first 300 s...

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...

A glassy carbon electrode was modified with graphene oxide nanosheets and a hybrid of copper-cobalt hexacyanoferrate. The nanocomposite was characterized by cyclic voltammetry, FT-IR and scanning electron microscopy. Cyclic voltammetry showed a stable and reversible redox pair with surface confined characteristics in phosphate buffer solution (0.1 M, pH 3). Hydrodynamic amperometry was used for...

A sensitive and selective procedure was developed for the spectrophotometric determination of silver by its catalytic effect on the oxidation of gallocyanine by peroxydisulphate in acidic media at 540 nm. Silver can be determined in the range of 0.001-0.500 µg/ml with a limit of detection of 0.0005 µg/ml, by a fixed-time method of 4.0 min from initiation of the reaction, The relative standa...

a kinetic method developed for the determination of ultra-trace amounts of nitrite based on its catalytic effect on the reaction between potassium bromate and nile blue a in strongly acidic media is reported. the reaction was monitored spectrophotometrically by measuring the decrease in absorbance of nile blue a at 645 nm by the fixed-time method. the decrease in absorbance during the first 0.5...

a new kinetic spectrophotometic method for the determination of trace amount manganese(ii) in tea real samples has been described based on it s the catalytic effect on the oxidations of 1 - (2 – pyridyl azo) - 2 - naphthol, (pan), by potassium bromated in sulfuric acid. the reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 547.5 nm. under the optimum con...

electrochemical oxidation of iodide has been studied in the presence of 2-thioborbituric acid using cyclic voltammetry and controlled-potential coulometry. the results indicate that, the resulting iodine takes part in halogenations reaction with 2-thiobarbituric acid. in addition, the present data are indicative of the suitability of iodide as a quasi mediator for determination of 2-thiobarbitu...