Study of 1,4-dihydroxyanthraquinone as an acid-base indicator in isopropyl alcohol medium Evaluation of colour-change limits through complementary chromaticity parameters.
The use of 1,4-dihydroxyanthraquinone as an acid-base indicator in isopropyl alcohol medium is proposed. The acid dissociation constants of the indicator in isopropyl alcohol solution are pK(a1) = 12.95 +/- 0.03 and pK(a2) = 15.96 +/- 0.07. The sharpness of the indicator transition is described by means of complementary chromaticity parameters. The indicator is used for determination of weak organic acids, with errors of less than 1%.
Barbosa
J
J
Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
Sanchez
J
J
Bosch
E
E