Selective Determination--of Lattthanum(III) by Ion Selective Electrode by Using Calixarene Darivatives as lonophore

摘要

The work in this paper is related with the synthesis and used of 2,11, 17, 23-Tetra-tert-butyl-22,27-bis-[(5'-hydroxy-3'-thiapentoxy)]-26, 28 dihydroxy calix[4] arene as electroactive material for the selective determination of La(III). The proposed with composition of o-NPOE: PVC: NaTPB: lonophore (57%: 37%: 5%: 1%) shows the best results. The electrode with o-NPOE as plasticizer worked in the concentration range of 1.0 x 10~(-9)- 1.0 x 10~(-2) with a detection limit of 1.0 x 10~(-9) and has Nernstian slope of 21.10 ± 0.3 mV per decade of activity, with a fast response time of 10s within the pH range of 1.5 to 9.5. The proposes electrode work satisfactorily in partial non-aqueous medium up to 30% nonaqueous content of methanol, ethanol and acetone, and was used as an indicator electrode for the titration with standard EDTA solution.