A solvent-dependent fluorescent detection method for Fe(3+) and Hg(2+) based on a rhodamine B derivative

Area of Science:

• Analytical Chemistry
• Materials Science
• Organic Chemistry

Background:

• Development of selective fluorescent probes for metal ion detection is crucial for environmental and biological monitoring.
• Rhodamine B derivatives are widely explored for their photophysical properties and sensing capabilities.

Purpose of the Study:

• To synthesize and characterize a new rhodamine B-benzofurazan based fluorescent probe.
• To investigate the probe's selective and sensitive detection of Fe(3+) and Hg(2+) ions.

Main Methods:

• Synthesis of the rhodamine B-benzofurazan based fluorescent probe (probe 1).
• Spectroscopic analysis (fluorescence, UV-vis) and Nuclear Magnetic Resonance (NMR) to study probe-metal interactions.
• Determination of binding ratios and detection limits for Fe(3+) and Hg(2+).

Main Results:

• Probe 1 exhibited selective fluorescent enhancement for Fe(3+) with different binding ratios (1:1 and 1:2) depending on concentration.
• The probe showed a highly selective and sensitive 'turn-on' fluorescent response to Hg(2+) with a detection limit of 4.4 nM.
• NMR and UV-vis studies confirmed distinct binding modes of probe 1 with Fe(3+) and Hg(2+), explaining the differential signaling.

Conclusions:

• The synthesized rhodamine B-benzofurazan probe is effective for the selective and sensitive detection of Fe(3+) and Hg(2+).
• The probe's distinct responses to different metal ions highlight its potential application in complex sample analysis.