Uranyl Microsensor: An Asymmetric Potentiometric Membrane Sensor Based on a New Calix[4]arene

Abstract

The first asymmetric potentiometric UO₂(II) microsensor is introduced. 5,11,17,23-tetra-tertio butyl(25,27),-bis)2-)n-]2-hydroxy-5-dinitridphenilonitrilidine) amino etoxy(26,28)-di hydroxy calix[4]arene (HAECA) was synthesized. It was found that HAECA can be used as an excellent ionophore in construction of UO₂(II) microsensor. The best performance was obtained with a membrane composition containing 20% PVC, 73% dibutyl phthalate, 5% HAECA, and 2% sodium tetraphenyl borate. The proposed microsensor exhibits a Nernstian slope of 28.5 ± 0.3 mV per decade over a wide concentration range of 1.0 ×10⁻¹⁰–1.0 × 10⁻⁴ M and a detection limit of 6.0 × 10⁻¹¹ M. The potentiometric response of the sensor is independent to the pH of the solution in the range of 2.2–3.6.

Keywords:

• 5,11,17,23-tetra-tertio butyl (25,27),-bis)2-)n-]2-hydroxy-5-dinitridphenilonitrilidine) amino etoxy(26,28)-di hydroxy calix[4]arene
• Micro-sensor
• Potentiometric PVC membrane
• UO₂(II)

The authors express their appreciation to the University of Tehran Research Council for financial support of this work.