Fluorimetric semiautomatic catalytic titrations

Abstract

The fluorimetric control of cemiautomatic catalytic titrations is described. The influence of several variables on the instrumental titration is established. A set of tests is proposed for evaluating the reliability of the device. This technique has been applied to the direct determination of EDTA (1.25–3.75 × 10^–5M, relative error 1.4%), which acts as an inhibitor of the oxidation of 2-hydroxybenzaldehyde thiosemicarbazone by hydrogen peroxide catalysed by iron(III). Methods are also described for the indirect catalytic titrations of iron(III) and alkaline-earth metal ions at parts per million levels (accuracy ca. 1%).