A Selective Colorimetric and Fluorescent Chemodosimeter for Fe(III) Ion Based on Hydrolysis of Schiff Base

Fluorescence determination of Fe(iii) in drinking water using a new fluorescence chemosensor

A new fluorescence chemosensor based on (Z)-2-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)hydrazine-1-carbothioamide (CEHC) has been developed for the determination of Fe(iii) in drinking water. The optimum conditions were acetate buffer solution with a pH 5.0. In this approach, the determination of Fe(iii) is based on static quenching of the luminescence of the probe upon increasing concentrations of Fe(iii). The CEHC sensor binds Fe(iii) in a 1 : 1 stoichiometry with a binding constant K_a = 1.30 × 10⁴ M⁻¹. CEHC responds to Fe(iii) in a way that is more sensitive, selective, and quick to turn off the fluorescence than to other heavy metal ions. Selectivity was proved against seven other metal ions (Mn(ii), Al(iii), Cu(ii), Ni(ii), Zn(ii), Pb(ii), and Cd(ii)). The calibration curve was constructed based on the Stern–Volmer equation. The linear range was 2.50–150 μM with the correlation coefficient of 0.9994, and the LOD was 0.76 μM. The method was successfully applied to determine Fe(iii) in drinking water samples, and the accuracy of the chemosensor was validated by atomic absorption spectrometry.

A new fluorescence chemosensor based on (Z)-2-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)hydrazine-1-carbothioamide (CEHC) has been developed for the determination of the fluorescence probe of Fe(iii) in drinking water.

Recent Advances on Iron(III) Selective Fluorescent Probes with Possible Applications in Bioimaging

Iron(III) is well-known to play a vital role in a variety of metabolic processes in almost all living systems, including the human body. However, the excess or deficiency of Fe3+ from the normal permissible limit can cause serious health problems. Therefore, novel analytical methods are developed for the simple, direct, and cost-effective monitoring of Fe3+ concentration in various environmental and biological samples. Because of the high selectivity and sensitivity, fast response time, and simplicity, the fluorescent-based molecular probes have been developed extensively in the past few decades to detect Fe3+. This review was narrated to summarize the Fe3+-selective fluorescent probes that show fluorescence enhancement (turn-on) and ratiometric response. The Fe3+ sensing ability, mechanisms along with the analytical novelties of recently reported 77 fluorescent probes are discussed.

UV-vis spectral property of a multi-hydroxyl Schiff-base derivative and its colorimetric response to some special metal ions

A multi-hydroxyl Schiff-base derivative, N-2'-hydroxyl-1'-naphthyl methylene-2-amino phenol (HNMAP), was synthesized and characterized by FTIR, ¹H NMR and UV-vis spectroscopy. It was noted to find there was great effect for solvent and pH on the UV-vis spectroscopy of HNMAP. Especially, some metal ions could make its UV-vis spectra changed regularly with different time-resolved effects. For example, a real-time and multi-wavelength response to Fe²⁺ at 520 nm, 466 nm and 447 nm and a quite slow one about 26 min to Fe³⁺ at 447 nm and 466 nm, respectively. Under the optimized conditions, the changes in the corresponding absorption intensities at above wavelengths were in proportion to c_Fe²⁺ or c_Fe³⁺ during respectively partitioned linear ranges, which realized to quantitatively detect Fe²⁺ or Fe³⁺ with a large linear range more than two orders of magnitude. A 1:1 complex mode for HNMAP-Fe²⁺ and 1:2 for HNMAP-Fe³⁺ were proposed from UV-vis spectral titration and Job's plot. HNMAP would be a potential sensor for colorimetric detection of Fe²⁺ and Fe³⁺ in practice.