Determination of ethambutol by a sensitive fluorescent probe

Area of Science:

• Analytical Chemistry
• Supramolecular Chemistry

Background:

• Cucurbit[7]uril (CB[7]) forms stable complexes with fluorescent probes like berberine and palmatine, enhancing their fluorescence.
• Ethambutol's interaction with these complexes leads to fluorescence quenching, indicating a potential analytical application.

Purpose of the Study:

• To investigate the competitive binding of ethambutol with berberine and palmatine within the CB[7] cavity.
• To develop novel fluorescence quenching methods for the sensitive determination of ethambutol.

Main Methods:

• Spectrofluorometry was employed to study the competitive reactions.
• Complex formation between CB[7] and fluorescent probes was analyzed.
• Fluorescence quenching by ethambutol was measured to establish analytical methods.

Main Results:

• Stable complexes of CB[7] with berberine and palmatine exhibited enhanced fluorescence at specific wavelengths (343 nm excitation, 495 nm emission).
• Ethambutol addition caused significant fluorescence quenching, enabling quantitative analysis.
• A linear correlation (r=0.9997) was observed between fluorescence quenching (ΔF) and ethambutol concentration (5.0-1000.0 ng mL⁻¹).
• A low detection limit of 1.7 ng mL⁻¹ was achieved.
• Berberine demonstrated higher sensitivity as a fluorescent probe compared to palmatine.

Conclusions:

• Novel and sensitive fluorescence quenching methods for ethambutol determination were successfully developed.
• The methods utilize the competitive interaction between ethambutol and fluorescent probes within the CB[7] cavity.
• The findings highlight the potential of berberine and palmatine as fluorescent probes for ethambutol analysis in supramolecular chemistry.