A comparative study of some hydroxyanthraquinones as acid-base indicators.
Alizarin, Alizarin S, quinizarin and quinalizarin have been compared as acid-base indicators with Bromocresol Green and Methyl Orange as reference indicators. The chromaticity co-ordinates, complementary chromaticity co-ordinates, pK(a) values, transition pH-range, pH of maximum colour change, optimum concentration for titrations and the quality of colour change were determined. The results show all four to be good indicators with a colour change quality similar to that of Bromocresol Green.
Barbosa
J
J
Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
Bosch
E
E
Carrera
R
R