A turn-on/off fluorescent sensor based on nano-structured Mg-Al layered double hydroxide intercalated with salicylic acid for monitoring of ferric ion in human serum samples.

The present work aimed to provide a novel chemosensor for ferric ion detection in human serum samples using nano-structured Mg-Al layered double hydroxide intercalated with salicylic acid (Mg-Al LDH-SA) as a sensitive fluorescence probe. The Mg-Al LDH-SA nanomaterial was synthesized and characterized via Fourier transform infrared spectroscopy, X-ray diffraction analysis, field emission scanning electron microscopy, dynamic light scattering and energy dispersive spectroscopy. The synthesized nanomaterial was applied to determine ferric ions by measuring the fluorescence intensity of Mg-Al LDH-SA sol solution at λ = 404 nm with excitation at λ = 287 nm. In the presence of ferric ions, the fluorescence intensity decreases owing to the formation of a stable complex between ferric ions and salicylic acid. Several important parameters affecting the analytical signal were studied and optimized. Under optimum conditions, the calibration graph was linear in the concentration range of 0.07-100 μmol L with a corresponding detection limit of 26 nmol L. The intra- and inter-day relative standard deviations (n = 6 and ferric ion concentration; 50 μmol L) were 3.4% and 4.5%, respectively. The method was successfully employed to assess ferric ion in several human serum samples with relative recovery values between 98.7 and 104.6% for the spiked samples.