A selectively fluorescein-based colorimetric probe for detecting copper(II) ion.

Area of Science:

• Analytical Chemistry
• Organic Chemistry
• Materials Science

Background:

• Fluorescein derivatives are widely used as fluorescent probes.
• Developing selective and sensitive chemosensors for metal ions is crucial for environmental and biological applications.
• Copper(II) ions play vital roles in biological systems but can be toxic at elevated levels.

Purpose of the Study:

• To synthesize and characterize a novel fluorescein derivative, furfuraldehyde fluorescein hydrazone (FFH).
• To investigate the potential of FFH as a selective and sensitive chemosensor for copper(II) ions (Cu2+).
• To evaluate the performance of FFH for Cu2+ determination in aqueous solutions.

Main Methods:

• Synthesis of FFH by reacting fluorescein hydrazide with furfuraldehyde.
• Characterization of FFH using spectroscopic techniques such as (1)H NMR, (13)C NMR, MS, and elemental analysis.
• UV-vis absorption spectroscopy to study the interaction between FFH and Cu2+ ions.

Main Results:

• FFH was successfully synthesized and characterized.
• Addition of Cu2+ to FFH resulted in a distinct color change (colorless to yellow) and a new absorption band at 502 nm.
• The interaction was attributed to the opening of the FFH spirocycle upon coordination with Cu2+ in a 1:1 ratio, with an association constant of 6.1×10(4) L mol(-1).
• FFH demonstrated a rapid, selective, and sensitive response to Cu2+ within a linear dynamic range of 6.6-330 μmol/L, with no interference from common ions.

Conclusions:

• FFH serves as an effective chemosensor for the rapid and selective detection of Cu2+ ions.
• The developed FFH probe exhibits high sensitivity and a wide linear dynamic range for Cu2+ determination.
• FFH shows potential for practical applications in monitoring Cu2+ levels in aqueous solutions.