Semi-automatic catalytic titration of some aminopoly-carboxylic acids, copper(II), and cobalt(II)

Abstract

A semi-automatic potentiometric method is described for the catalytic titrimetric determination ofμg amounts of some aminopolycarboxylic acids. The method is based on their inhibitory effect on the copper(II)-catalyzed periodate-thiosulfate reaction. Amounts of EDTA in the 0.7–600μg range (10−6−8×10−5M), of DCTA in the 7–7000μg range (10−6–10−3M), of EGTA in the 0.8–800μg range (10−7−10−4M), and of DTPA in the 4–800μg range (5×10−7–10−4M) were determined with average relative errors and coefficient of variation of about 0.4–1%. The method has also been used for the indirect catalytic titrimetric determination ofμg amounts of Cu2+ and Co2+ ions with about the before mentioned accuracy and precision.