Evaluation of 1-(2-thiazolylazo)-2-hydroxy-3-naphthoic acid as a metallochromic indicator.
The acid dissociation constants of 1-(2-thiazolylazo)-2-hydroxy-3-naphthoic acid (TAHN) and the formation constants of Cu(II), Ni(II) and Zn(II) chelates of this dye have been determined spectrophotometrically at 25 degrees in a 5% v/v mixture of dioxan and water. The formation constants of the 1:2 chelates are smaller than those of other o-hydroxythiazolylazo compound chelates. TAHN is a satisfactory indicator for the titrations of Cu(II) and Ni(II) with EDTA.
Wada
H
H
Nagoya Institute of Technology Laboratory of Analytical Chemistry Showa-ku, Nagoya, Japan.
Nakazawa
O
O
Nakagawa
G
G