1978 Volume 27 Issue 10 Pages 607-611
This method consisted of the consecutive three stages of procedure, i.e., the separation of selenium with a column of cation exchange resin, the conversion of selenium(IV) to hydrogen selenide with a pellet of zinc powder and binder, and the sweeping of selenide into a quartz cell of atomic absorption spectrophotometer. A given amount of particulate samples was gently heated in concentrated nitric acid together with a small amount of hydrogen peroxide in a water bath. After removing the insoluble residue, the solution was evaporated to dryness. The residue was taken up into 0.05 mol/l nitric acid, and introduced into a column φ 0.8×12cm, packed with Dowex 50WX8 {(50 100)mesh} in the hydrogen form. The effluent was evaporated to remove nitric acid and the residue was dissolved in 25 ml of 3.5 mol/l hydrochloric acid. The solution containing less than 1 μg of selenium was put into a reaction vessel, a pellet of zinc was added and the solution was covered tightly with the plunger. When the pressure guage reached 0.5 kg/cm2, hydrogen selenide evolved was carried away into the cell with nitrogen carrier. Selenium ranging from 0.1 to 5μg was determined in this way with a error of 3 %. Without the separation by ion exchange, copper, and chromium much interfered with the determination.
