Semi-Automatic Titrators for High Precision Volumetric Determinations

Abstract

A B S T R A C TIn the potentiometric determination of stability constants, the information is very often obtained from titrations. Not only is each individual titration very lengthy because of the stabi lization period for the electrode potentials and the great number of volume increments, but many such titrations are necessary to gather sufficient information. The prospect of performing such work manually offers little attraction for the investigator and increases the risk of introducing subjective criteria. Therefore the authors sought to develop semi automatic systems with a high reproducibility for precision work without losing the advantage of the instant decision offered by manual work. Three different titrators are discussed. The first apparatus delivers a constant volume and types the results after a pre set interval. The second titrator controls the volume addition and the stability of the emf measurement. A description is given of the programming unit and the necessary adjustments. In the third titrator, all control is performed by a PDP 8/E computer which offers, of course, more possibilities. The concept of the software package, written in an assembly 21