Spectrophotometric Determination of Selenium with 1-Naphthyloamine-7-sulfonic Acid.

KINETIC DETERMINATION OF ASCORBIC ACID a WITH SPECTROPHOTOMETRIC DETECTION

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...

Flow injection spectrophotometric determination of trace amounts of selenium.

A simple, rapid and sensitive flow injection spectrophotometric method for determination of selenium (0.005-1.5 mug ml(-1)) is described. The method is based on the catalytic effect of Se(IV) on the reduction reaction of thionine (TN) with sulphide ion, monitored spectrophotometrically at 598 nm. The detection limit is 5 ng ml(-1) the relative standard deviation for eight replicate measurements...

A facile spectrophotometric method for the determination of selenium.

A rapid and sensitive spectrophotometric method is described for the determination of trace amounts of selenium using Variamine Blue (VB) as a chromogenic reagent. The proposed method is based on the reaction of selenium with potassium iodide in an acidic medium to liberate iodine, which oxidizes Variamine Blue to form a violet-colored species having an absorption maximum at 546 nm. Beer's law ...

Spectrophotometric Determination of Selenium in Environmental, Biological and Pharmaceutical Samples

Spectrophotometric Determination of Tantalum(V) with 5-Iodo-8- -hydroxyquinoline-7-sulphonic Acid

Tantalum(V) reacts with 5-iodo-8-hydroxyquinoline-7-sulphonic acid to form a yellowish coloured complex having maximum absorbance at 405 nm in citric acid medium. The relatively slow reaction at room temperature is completed in 10 minutes at 40 °c. The colour is stable for at least 12 hr. Effects of heating temperature, time, pH, reagent concentration and other variables have been studied. The ...