An Improved Standard Addition Potentiometry in Water-Organic Solvent Mixtures

Abstract

An improved standard addition potentiometry for a sample of waterorganic solvent mixtures, in which the adjustments of both the ionic strength and the solvent composition are not required, is proposed.
After the sample of the waterorganic solvent mixture of volume V, in which an ion-selective electrode and a reference electrode are immersed, is titrated with the aqueous solution of the diluent and the electromotive forces (E¹) which correspond to volumes (vd) of the added diluent are measured (the final volume of the added diluent is denoted with vdo) the same sample solution of another certain volume WO is added to the titrated sample. Subsequently this mixed sample is titrated again with the aqueous solution of the standard containing the analyte ion of a known concentration (cs) and having the same ionic strength as that of the diluent, and the electromotive forces (E²) which correspond to volumes (vs) of the added standard are measured.