Analytical Sciences

Abstract − Analytical Sciences, 21(3), 293 (2005).

Strontium(II) Sensor Based on a Modified Calix[6]arene in PVC Matrix
Vinod Kumar GUPTA,* Rainer LUDWIG,** and Shiva AGARWAL*
*Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 India
**Institute for Inorganic and Analytical Chemistry, Freie Universitaet, Berlin 14195, Germany
5,11,17,23,29,35-Hexakis(1,1,3,3-tetramethylbutyl)-37,38,39,40,41,42-hexakis(carboxy methoxy)calix[6]arene (I) has been evaluated as an ionophore for the analysis of Sr2+. The influences of the nature of the plasticizers (DBA, CN, DOP, NPOE) and of the anion excluder (NaTPB) on the characteristics of the electrode were discussed. The best electrode was fabricated with a membrane having composition 6:150:170:3 (I:PVC:DBA:NaTPB). The response to Sr2+ was Nernstian in the range 1.9 × 10-5 to 1.0 × 10-1 M of Sr2+. The influence of pH has also been studied. The electrode exhibited better potential stability and had an operational lifetime of 4 months. The KA,BPot values showed that other alkaline earth metal ions are well discriminated. The sensor has also been used as an indicator electrode in the potentiometric titration of sodium carbonate with strontium(II) ions.