Ag+-sensitive membranes for electrochemical and optical sensors

The paper is focused on lipophilic acyclic thioethers as neutral ionophores for heavy-metals cations. Membranes based on plasticized PVC containing these carriers exhibited high selectivity toward silver cations over transition metal ions (log KAgM < -4.5) except mercury ions. Membrane containing the ionophore II (with l-naphtyl pendant group) was used to design silver-selective ISE which shows linear response in the range 3 - 6 pAg with a slope of 51.5 mV/pAg. The addition of the pH chromoionophore to the membrane composition allowed to obtain a silver-sensitive optrode membrane, responding in the concentration range 0.01 - 1 mM Ag+.