Ion-Selective Electrode Solid Contact Base on Neutral-Carrier Ditiophosphate for Mercury Determination at Nanomolar Levels

Potentiometric studies for ion-selective electrodes solid contact based on neutral carriers that contain in their structure sulphur donor groups and an aliphatic chain is presented, this chain may confer stability to the molecule for the formation of metal complexes. The result was obtaining an ISE, for the potentiometric determination of mercury. This sensor allowed continuous mercury measurements at nanomolar levels within a wide concentration interval (1.0 x 10⁻⁹ a 1.0 x 10⁻¹) mol L^-1, with a detection limit of (9.1 ± 0.8) x 10⁻¹⁰ mol L^-1 and a Nernstian response of (29.8 ± 0.4) mV decade^-1. The ISE can be used in the 0 – 6 pH interval; it exhibited a high selectivity toward the mercury ions even in the presence of interferents, and can be used as an indicating electrode during potentiometric mercury titration with EDTA, because it is comparable, within its same class with the commercial electrodes.