Sensitive fluorescent assay for copper(ii) determination in aqueous solution using quercetin-cyclodextrin inclusion.

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Copper ions are essential but toxic at high concentrations, necessitating accurate detection methods.
• Developing environmentally friendly and selective probes is crucial for monitoring copper levels.

Purpose of the Study:

• To develop a novel fluorescent probe for sensitive and selective detection of copper ions.
• To investigate the mechanism of fluorescence quenching by copper ions using a quercetin-(2-hydroxypropyl)-β-cyclodextrin system.

Main Methods:

• Utilized fluorescence spectroscopy and UV/Vis spectroscopy to characterize the probe.
• Employed fluorescence titration to determine copper ion concentration.
• Investigated the reaction mechanism using Job's plot analysis.

Main Results:

• The quercetin-(2-hydroxypropyl)-β-cyclodextrin system showed enhanced fluorescence intensity.
• Selective fluorescence quenching was observed in the presence of copper ions, with a linear response from 5.0 × 10^-8 to 8.3 × 10^-6 mol L^-1.
• A low detection limit of 2.3 × 10^-8 mol L^-1 was achieved, and the probe was successfully applied to real samples.

Conclusions:

• The developed quercetin-(2-hydroxypropyl)-β-cyclodextrin probe is highly selective and sensitive for copper ion detection.
• The probe offers a promising environmentally friendly approach for monitoring copper in water and food samples.
• The mechanism involves the formation of a Q-CD-Cu(ii) complex and intramolecular charge transfer.