PVC based dibenzo-18-crown-6 electrode for Ca(II) ions

A new PVC based membrane using dibenzo-18-crown-6 (DB18C6) as an ionophore has been developed as a calcium ion selective electrode. The electrode comprises of ionophore (7%), PVC (85%) and plasticizer (8%). The electrode shows a linear dynamic response in the concentration range of 1 x 10(-5) M to 1 x 10(-1) M with a Nernstian slope of 28.0 mV/decade and a detection limit as 4 x 10(-6) M. It has a response time of <30 s and can be used for at least 5 months without any significant divergence in potentials. The proposed sensor shows reasonably good selectivity with respect to alkali, alkaline earth and transition metal ions. It can be used in the pH range 3-11. The electrode has been used as an indicator electrode in potentiometric titrations of calcium(II) ions with EDTA. (C) 2003 Elsevier B.V. All rights reserved.