TRANSIENT SIGNALS WITH AN ANTIMONY(V) ION-SELECTIVE ELECTRODE - THE RELATIVE SIGNAL RETURN RATE AS A SELECTIVITY PARAMETER

The dynamic response of a Sb5+ ion-selective electrode based on 1,2,4, 6-tetraphenylpyridinium hexachloroantimonate(V) to different ions, ClO 4-, HgCl3-, AuCl4-, TlCl4-, SbCl6- and tetraphenylborate, in a flow-in jection analysis system using a flow-through cell, is studied. The tra nsient signals obtained are different for every ion. A parameter calle d relative return rate, defined as the ratio of the return rate to pea k height, was found to be characteristic for each ion. It was constant up to a concentration range of three decades for those ions with sele ctivity coefficients K(sb j)pot much less than 1, thus providing a new source of analytical selectivity. Flow injection variables were studi ed in order to ascertain their influence on this new parameter.