Dipodal tetraamide derivatives of 1,10‐diaza‐18‐crown‐6 and alkylmalonic acids—synthesis and use as ionophores in ion selective membrane electrodes

Abstract

Novel dipodal derivatives of an 18‐membered diaza‐crown ether with two diamide chains featuring methylmalonic or butylmalonic acid residues were obtained and tested as ionophores in ion‐selective plasticized membrane electrodes. The objective of the study was to identify measurement conditions which ensure the most favorable performance for magnesium ion‐selective elec-trodes. The relationship between the molar lipophilic anion salt‐to‐ionophore ratio and selectivity of electrodes was examined. The best result was obtained for the conventional electrode containing Mg2 ionophore. Calculated selectivity coefficients were as follows: logKMg/Ca = −2.77, logKMg/Na = −3.46 and logKMg.K = −2.24 (SSM, 1M).