Spectroscopic Properties of Apigenin in Various Bulk Solutions and Aerosol‐OT Reverse Micelles

Abstract

The fluorescence and ultraviolet (UV)/visible absorption spectra of apigenin (API) were measured and examined in bulk solutions and aerosol-OT (AOT) reverse micelles. The Stokes' shift in micelles is very small due to the small dipole moment change upon excitation. Since the intermolecular interaction between API and H 2 O in micelles is weak, the fluorescence parameters are relatively insensitive to the change in water concentration compared with those in bulk solutions. Since the B ring can rotate freely, the dihedral angle between the A, C, and B rings can be changed easily by the influence of the solvent. The potential energy curves of the electronic states show a very shallow or no minimum. Although the change in electronic energy by intermolecular interaction will be very small, the point where emission occurs on the energy curve can be altered very sensitively. Due to these reasons, the fluorescence properties of API are very sensitive to changes in excitation wavelength and solvent.

Integration of phase separation with ultrasound-assisted salt-induced liquid–liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography

“…Therefore, sensitive and selective analytical methods for the determination of FQs in plasma and urine or other biological fluids are urgently required. To date, many methods have been developed for the determination of FQs in many matrices, such as spectroscopy [8], capillary electrophoresis [9], spectrofluorometry [10][11][12], potentiometric titration [13] and high performance liquid chromatography (HPLC) [14,15] coupled with mass spectrometry (MS) [16]. Because of interference from complex matrices in biological fluids, these analytical methods often require extensive sample preparation.…”