Novel PVC Based Ion Selective Electrode for Cr(III) by using 8,11,14-Triaza-1,4-dioxo-5(6),6(17)-ditolylcycloseptadecane (TADODTSD) Ionophore

A potentiometric response of an ion-selective electrode with a new ionophore 8,11,14-triaza-1,4-dioxo-5(6),16(17)-ditolylcycloseptadecane (TADODTSD) toward Cr(III) ions was studied. The designed electrode showed a Nernstian behavior with a slope of 19.6±0.5mV/decade in a working concentration range of 1.0×10-8-1.0×10-1 mol L-1 and a detection limit of 8.0×10-8 mol L-1. A membrane composition made of PVC: DBP: ionophore (TADODTSD): NaTPB; 30%: 60%: 8%: 2 wt.% displays the best results. Response time was found to be 7 seconds and can be used for 120 days without showing any substantial deviation in potential. The proposed electrode exhibits selectivity for Cr(III) ions. The electrode worked well under laboratory conditions with its, potential response being constant over a pH range of 3.0-8.0. The electrode proposed in this work could be used to determine the presence of Cr(III) ion in wastewater and also an indicator electrode with EDTA.