Double-armed calix[4]arene amide derivatives as ionophores for lead ion-selective electrodes

A number of double-armed calix[4]arene amide derivatives (1–7) have been tested as the neutral ionophores for lead ion-selective electrodes. The electrodes based on ionophores 1–7 except 5, 6 with dioctyl phthalate (DOP) as a plasticizer exhibit a close theoretical Nernstian response for Pb2+ over a relatively wide concentration range (1 × 10−6–1 × 10−1 M), a fast response time (<15 s), at least two months lifetime and good selectivity towards alkali, alkaline earth and some common transition metal ions.