The effect of lipophilic anionic additives on detection limits of ion-selective electrodes based on ionophores with phosphoryl complexing groups

The dependence of detection limits of ion-selective electrodes (ISEs) based on ionophores with phosphoryl-containing terminal groups on the nature and concentration of lipophilic anionic compounds was investigated. It was shown that by including superstoichiometric amounts of lipophilic anionic compounds into the membrane, the lower detection limit can be decreased significantly. A model describing the mechanism of the dependence of the lower detection limits on both the amount and nature of the lipophilic anionic additives used is presented.