Lowering the Detection Limit of Solvent Polymeric Ion-Selective Membrane Electrodes. An Experimental Study with Calcium-Selective Micropipette Electrodes

Abstract

Ion-selective microelectrodes (ISMEs) in the range of 2–90 µm were investigated using different composition of inner reference electrolytes (IRE). The electrodes prepared were PVC-free solvent polymeric based calcium-selective (Ca-ISMEs) micropipette ones. Efforts were done to find an optimal composition of the membrane, IRE, and pipette size in order to reduce the apparent super-Nerstian part of the calibration curves for Ca²⁺-measurements in the submicromolar range. As a result, we could find an optimal composition, which was linear down to about 10⁻⁸ M.

Keywords:

• Ion-selective microelectrodes
• Lower detection limit
• Polymer membrane electrode
• Inner reference solution
• Calcium-selective electrode

Acknowledgements

We gratefully acknowledge the financial support of the TéT Finnish-Hungarian bilateral cooperation (grant no.: SF 10/01), the support from OTKA (T 037403) and M. S. for his grants from ERASMUS, TEKES, and CIMO.