Lanthanide Recognition: Development of an Asymetric Gadolinium Microsensor Based on N-(2-pyridyl)-N′-(4-nitrophenyl)thiourea

Abstract

The first asymmetric potentiometric Gd(III) microsensor is reported here. N-(2-Pyridyl)-N′-(4-nitrophenyl)thiourea (PyTu₄NO₂) was found to have a very selective and sensitive behavior toward Gd(III) ions, in comparison to other lanthanide ions as well as inner transition and representative metal ions and hence was used as a sensing material in the construction of a Gd(III) microelectrode. The Gd(III) sensor exhibits a Nernstian slope of 17.46 ± 0.3 mV per decade over the concentration range of 1.0 × 10⁻⁸ to 1.0 × 10⁻³ M and a detection limit of 3.0 × 10⁻⁹ M of Gd(III) ions. The potentiometric response of the sensor is independent of the solution pH in the range of 4.0–9.0. It manifests advantages of low detection limit and fast response time (10–15 s).

Keywords:

• Gd(III)
• microsensor
• N-(2-pyridyl)-N′-(4-nitrophenyl)thiourea
• potentiometric membrane

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