Rhodamine-based turn-on fluorescent and colorimetric chemosensor for selective Pb²⁺ detection: insights from crystal...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Lead (Pb²⁺) contamination poses significant environmental and public health risks.
• Effective and sensitive detection methods for Pb²⁺ are crucial for monitoring and mitigation.

Purpose of the Study:

• To design and synthesize a novel rhodamine-based Schiff base chemosensor (L) for selective Pb²⁺ detection.
• To evaluate the sensor's performance in terms of selectivity, sensitivity, and practical applicability.

Main Methods:

• Synthesis of a rhodamine-based Schiff base chemosensor (L).
• Spectroscopic analysis (colorimetric and fluorescence) for Pb²⁺ detection.
• Binding studies (Job's plot, Benesi-Hildebrand analysis) to determine stoichiometry and binding constant.
• Density Functional Theory (DFT) and molecular docking for computational analysis.
• Real-world sample analysis (water samples, solid-state, filter paper assays).

Main Results:

• The chemosensor (L) exhibited high selectivity and sensitivity for Pb²⁺ ions.
• A distinct turn-on fluorescence response and color change were observed upon Pb²⁺ binding.
• The sensor bound Pb²⁺ in a 1:1 ratio with a strong binding constant (K_a = 0.954 × 10⁴).
• The limit of detection for Pb²⁺ was determined to be 3.77 nM.
• DFT and molecular docking studies confirmed complex stability and potential DNA interactions (-5.7 kcal mol^-1).
• Successful Pb²⁺ detection in real water samples and various assay formats was demonstrated.

Conclusions:

• The novel rhodamine-based Schiff base chemosensor (L) is a highly effective tool for sensitive and selective Pb²⁺ detection.
• The sensor's practical applicability in environmental monitoring and potential for therapeutic applications were confirmed.
• This work provides a valuable method for addressing lead contamination concerns.