A new fluorescent chemosensor for Al(III) detection with highly selective in aqueous solution and solid test paper

A simple 'turn-on' fluorescence chemosensor for Al(iii) detection in aqueous solution and solid matrix

A simple fluorescence chemosensor of FHS-OH based on salicylaldehyde Schiff base was developed via a one-step reaction, which achieved a fast and highly selective response for Al(iii). Mechanism studies showed that when FHS-OH was exposed to Al(iii) with 1 : 2 binding stoichiometry in an aqueous solution at neutral pH, C[double bond, length as m-dash]N isomerization and PET processes were limited, resulting in a 'turn-on' fluorescence response with a low detection limit of 63 nmol L-1 and a satisfying linear range of 0.0-20.0 μmol L-1. Compared to traditional detection methods for Al(iii), fluorometry using FHS-OH has several advantages, including simplicity, quick response, and capability of real-time detection. More importantly, the detection of Al(iii) on a solid matrix (test paper) was successfully achieved. After the addition of Al(iii), a significant emission colour change from green to bright blue was observed by the naked eye owing to the intrinsic aggregation-induced emission (AIE) characteristic of FHS-OH.

A pyridine modified naphthol hydrazone Schiff base chemosensor for Al3+ via intramolecular charge transfer process

A pyridine modified naphthol hydrazone Schiff base chemosensor, NaPy, was prepared in a two-step process to detect aluminum ion (Al3+) in different samples. The probe shows a turn-off emission response towards Al3+ at a 1:1 binding stoichiometry via intramolecular charge transfer (ICT) mechanism, as validated by density functional theory (DFT) calculations and a series of spectroscopic measurements. The response time is slightly over one minute with a limit of detection (LOD) value of 0.164 µM, demonstrating the great sensitivity of the probe. It is also found that NaPy exhibits high selectivity towards Al3+ and resists interference from seventeen other cations. Application investigations in paper strips, water samples and HeLa cells suggest that NaPy can be used as an efficient probe for sensing Al3+ in real environmental samples and biosystems.

A New Azo-Schiff Base Dual-mode Chemosensor: Colorimetric Detection of Cobalt Ions and Fluorometric Detection of Aluminum Ions in Aqueous Ethanol Solution

A new Azo-Schiff base ligand (H₂L) was designed and synthesized as a cation chemosensor. The chemosensor H₂L as dual chemosensor showed selective fluorescence recognition of Al³⁺ with a noticeable fluorescence enhancement and colorimetric detection of Co2 + in aqueous ethanol solution. The H₂L exhibits a linear response toward Al³⁺ ions in the concentration range of 1.91 × 10^-8 M to 4.8 × 10^-6 M with a limit of detection of 1.91 × 10^-8 M. The sensing mechanism of sensor H₂L toward Al³⁺ was investigated by 1H NMR and IR spectroscopies. Fluorescence switch based on the control of EDTA and Al³⁺ proved H₂L could act as a reversible chemosensor. The molecular structure of [NiL] complex has been determined by X-ray crystallography.