Design of a Novel Gadolinium Optical Sensor Based on Immobilization of (Z)-N′-((Pyridine-2-yl) Methylene) Thiophene-2-carbohydrazide on a Triacetylcellulose Membrane and Its Application to the Urine Samples

Abstract

In this work, for the first time we report a highly selective and sensitive Gd(III) optical sensor based on immobilization of (Z)-N′-((pyridine-2-yl) methylene) thiophene-2-carbohydrazide (PMTC) on a triacetylcellulose membrane. This optode exhibits a linear range 5.0 × 10⁻⁸ to 2.0 × 10⁻⁵ M of Gd(III) ion concentration with a detection limit of 1.1 × 10⁻⁸ M. The response time of the newly designed optode was within 1–2 min, depending on the Gd(III) ion concentration. The response of the sensor is independent of the pH solution in the range of 2.0–9.0. It manifests advantages of low detection limit, fast response time, and most significant, very good selectivity with respect to a number of lanthanide ions (La, Ce, Sm, and Eu ions). The proposed sensor could be successfully regenerated with a thiourea solution. Its response was reversible and reproducible (RSD less than 1.3%). This optode was applied to the determination of Gd(III) in synthetic and real samples.

Keywords:

• (Z)-N′-((pyridine-2-yl) methylene) thiophene-2-carbohydrazide (PMTC)
• gadolinium
• optical sensor
• thiourea
• triacetylcellulose

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

Notes

^a Maximum ratio of the foreign ions to the gadolinium ions (0.1 µM) giving an error of <5%.

^a Detection limit.

^b Linear range.