The first application of solid phase extraction (SPE) started approximately five decades ago, and until then development of SPE materials is continued, and it seems to be a never-ending story. Lately, research is focused in developing more explicit materials to achieve meticulous separation of ions from solutions containing complex matrices with high concentrations of interfering ions. One group of SPE materials includes those with macrocyclic ligands immobilized on a silica or polymer support; this type of SPE has been reportedly available for ion-selective separation and pre-concentration...