Abstract
This work deals with the evaluation of different thiacalix[4]arene derivatives included in polymeric PVC membranes for the optical sensing of metallic cations. Two ligands have been studied: thiacalix[4]arene (ligand 4) and its p-tert-butyl-derivative (ligand 2). Membranes including ligand 4 were tested for different metals and better results were obtained for Cd2+, Ag+, and Pb2+. In the case of films incorporating the neutral ionophore, ligand 2, a pH sensitive dye (ETH 2439), and an anionic additive were also added. A selective response to Ag+ was achieved in acetate buffer at pH 5.
Acknowledgments
This study has been financed by the Spanish Ministry of Foreign Affairs through the scientific cooperation project A/5569/06 and by the Spanish National Research Programme project CGL2007-66861-C4.
Notes
*(1) = thiacalixarene 4; (2) = thiacalixarene 2.
*measured with ICP-OES.
**measured with the proposed optical membrane system.