A new method for the gravimetric determination of selenium using 1, 2, 3-trimethyl-3-pyrazolin-5-thione

Analytical studies on thiopyrazolone derivatives. IV

Abstract

1, 2, 3-Trimethyl-3-pyrazolin-5-thione reacts with Se(IV) in hydrochloric acid-sodium citrate buffer at pH 34.5 and precipitates quantitatively metallic selenium from a hot solution. The reaction was applied to the gravimetric determination of 20550mg of selenium with good result. The method was scarcely influenced by other ions. Te(IV) reacts with the reagent to form a water-soluble complex and hence the method is especially suitable for the separatory determination of selenium and tellurium.