SPECTROPHOTOMETRIC DETERMI NATION OF OSMIUM (VIII) WITH 1-HYDROXY 2- PYRIDINE - THIONE (SODIUM SALT) AS A REAGENT

A spectrophotometric study of osmium (VIII) complex of 1-hydroxy 2- pyridine thione (HPT) is presented. A red-violet complex, 0 s (HPT) is formed in a highly acidic solution, and shows maximum absorbance at 500 nm with molar absorptivity of 5.12 x 101. mol . cm . Beer's law is obeyed in the range of 3-60 ppm. Sandel's sensitivity of the method is 0.37 ?g.cm per0.001 ab sorbance unit. V (V), Pt (IV), Cu (II), Sn (IV), Cr (VI), and NO . interference. To overcome the interference and improve the selectivity, the 0 s (VIII) as OsO isextracted inCC1 and theextracted 0s (VIII) is converted to the complex and measured spectrophotometrically. This method reduces the number of interferences to V(V), Pt (IV), and NO -. The method offers the advantages of simplicity, speed and high precision. A spot test for the detection of traces of osmium is also presented