Spectrophotometric Determination of Trace Amounts of Cobalt and Copper with 3- (2′-Thiazolylazo)- 2,6- Diaminopyridine

Abstract

Sensitive methods for the determination of trace amounts of cobalt and copper by complexation with 3-(2′-Thiazolylazo)-2,6- diaminopyridine (2,6-TADAP) are described. Copper forms a 1:2 violet complex with the reagent having a molar absorptivity of 1.00 × 10⁴ L mol⁻¹cm⁻¹, Baer's law is obeyed over the range 0 −50.84 μg in the total volume of 10ml. Cobalt also forms a 1:1 green complex with a molar absorptivity of 1.07 × 10⁴L mol⁻¹cm⁻¹ and obeying Beer's law over the range 0 –23.57 μg in the total volume of 10 ml. The procedure is simple and rapid without any tedious extraction steps for copper and without oxidation of cobalt (II) to cobalt (III).

Key Words:

• Cobalt
• Copper
• Spectrophotometric determination 3-(2′Thiazolylazo)-2,6-Diaminopyridine