Application of microprocessors to chemical analysis: sequential titration of adipic and boric acids

Abstract

An automatic titrator has been designed so that titrations and processing of the results are controlled by a microprocessor. The titrant is added stepwise, in equal volumes, to the sample and the potential is measured after each addition. The instrument has been used for the successive titration, against sodium hydroxide, of a mixture of adipic and boric acids. The method for the determination of the equivalence volumes is based on the differential plot of ΔpH/ΔV against V. The effect on the results of varying the rate of addition of titrant, the rate of stirring and the orientation of the electrodes and delivery tube have been examined. The accuracy and precision obtained compare favourably with those of the standard potentiometric titration procedure, in which mannitol is added for the titration of boric acid and the titrant is added until a pre-selected potential is reached.