Interaction of thyroxine with 7 hydroxycoumarin: a fluorescence quenching study

Area of Science:

• Biochemistry
• Analytical Chemistry

Background:

• Thyroxine is a crucial thyroid hormone regulating metabolism.
• 7 hydroxycoumarin (7HC) is a fluorescent compound with potential applications in molecular sensing.

Purpose of the Study:

• To investigate the interaction between thyroxine and 7HC.
• To develop a fluorescence-based method for thyroxine detection.

Main Methods:

• Fluorescence quenching spectroscopy was employed to study the binding interaction.
• The 7HC-thyroxine complex formation was analyzed using static quenching mechanism.
• Thermodynamic parameters were calculated to elucidate binding forces.

Main Results:

• Thyroxine induced static quenching of 7HC fluorescence, indicating complex formation.
• Binding constants (K) were determined at different temperatures (1.51 x 10^4 at 297 K, 9.06 x 10^3 at 310 K).
• The interaction is primarily mediated by hydrogen bonding and van der Waals forces.
• A linear calibration curve for thyroxine was established in the range of 2.0 x 10^-8 to 3.0 x 10^-7 mol/l.
• The method demonstrated good precision (RSD 2.58%) and a low limit of detection (3.42 x 10^-8 mol/l) in CTAB medium.

Conclusions:

• The fluorescence quenching method provides a sensitive and reliable approach for thyroxine determination.
• The study elucidates the molecular interaction mechanism between thyroxine and 7HC.