Development of the Smartphone-Assisted Colorimetric Detection of Thorium by Using New Schiff's Base and Its...

Area of Science:

• Analytical Chemistry
• Sensing and Detection
• Materials Science

Background:

• Accurate detection of Thorium (Th⁴⁺) is crucial for environmental monitoring and industrial applications.
• Development of selective and sensitive chromogenic sensors is essential for efficient metal ion analysis.
• Existing methods for Th⁴⁺ detection can be complex and require specialized equipment.

Purpose of the Study:

• To develop a novel chromogenic sensor (L) for the selective detection of Thorium (Th⁴⁺) ions.
• To investigate the sensing capabilities of L in solution and on paper strips using spectrophotometric and colorimetric methods.
• To explore the integration of the sensor with smartphone technology for real-time Th⁴⁺ analysis.

Main Methods:

• Synthesis of the sensor L by reacting 1,10-phenanthroline-2,9-dicarbohydrazide with 2-hydroxy naphthaldehyde.
• Spectrophotometric and colorimetric analysis of L's interaction with Th⁴⁺ and other metal ions.
• UV-visible spectral studies, ¹H NMR, electrospray ionization-mass spectrometry, and theoretical calculations to elucidate binding modes.

Main Results:

• The sensor L exhibited a distinct color change (colorless to yellow-orange) upon selective binding with Th⁴⁺.
• The sensor demonstrated high selectivity for Th⁴⁺ over other f-metal ions and s-block/d-block elements.
• A 1:1 host-guest complex was formed with Th⁴⁺, with a limit of detection as low as 50 nM (spectrophotometry) and 116 nM (smartphone analysis).
• Successful application of the sensor for Th⁴⁺ determination in real water, monazite, and lantern mantle samples.

Conclusions:

• The developed sensor L is a highly selective and sensitive tool for the naked-eye detection and quantification of Th⁴⁺.
• The sensor's compatibility with smartphone technology facilitates rapid, on-site, and cost-effective real-time Th⁴⁺ analysis.
• The findings present a promising approach for monitoring Th⁴⁺ in diverse environmental and industrial settings.