Water Soluble Pyridylazoaminophenols and Pyridylazoaminobenzoic Acids as Highly Sensitive Photometric Reagents for Zinc, Uranium, Cobalt and Nickel

Abstract

A series of water-soluble derivatives of pyridylazoaminophenol and pyridylazoaminobenzoic acid have been synthesized; they were evaluated as highly sensitive chromogenic reagents for metals. 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (5-Br-PAPS) and 2-(3, 5-dibromo-2-pyridylazo)-5-(N-ethyl-N-sulfopropylamino) benzoic acid (DSAB) were found to be highly sensitive reagents, the former for zinc(ε=13.3×10⁴ at 552nm) and uranyl (ε=6.6×10⁴ at 578nm), and the latter for cobalt(III) (ε=15.2×10⁴ at 670nm)and nickel (ε=13.7×10⁴at 620nm).