A simple quinoline derivative as fluorescent probe with high sensitivity and selectivity for Al3+ in aqueous solution

A photochromic salicylaldehyde hydrazone derivative based on CN isomerization and ESIPT mechanisms and its detection of Al3+ in aqueous solution

A simple photochromic Schiff base was successfully prepared by the condensation of salicylaldehyde and benzoyl hydrazine. This compound has reversible photochromic properties based on isomerization and ESIPT mechanisms. In organic solvents, after irradiation with 365 nm UV light for 2 min, the absorption peak at 367 nm of the compound showed a significant decrease, while a double absorption peak appeared at 418 nm and 438 nm, accompanied by a significant change of the solution color from colorless to yellow. The compound can also complex with Al³⁺ at the molar ratio of 2:1 in the water solution (acetonitrile/water, v/v, 1:99), resulting in significantly enhanced fluorescence of the compound, so as to achieve fluorescence detection of Al³⁺ in living cells and water samples.

A Pyrene-Tetrazole Fused Fluorescent Probe for Effective Real Time Detection Towards Aluminium Ion

We constructed a novel-binding site for metal ion detection using a fused tetrazole ring conjugated with aminopyrene (R). The designed structure of the molecule was successfully synthesized and determined the probe's selectivity by testing various metal ions and found that the probe effectively detects Al³⁺ ion visually. Checked the sensing ability of the probe with different approaches (fluorimetric and colorimetric), and the effectiveness is double confirmed. The added Al³⁺ ion to R procured a rapid change in color from yellowish orange to colorless. Under the UV lamp, a turn-on blue fluorescence was observed after adding aluminium ion, whereas the probe was non-fluorescent before detecting aluminium ion. The probable interface of the probe with aluminium ion has also been expected from HRMS spectral analysis results. The probe's utility in real-time monitoring of Al³⁺ ion in water is confirmed by a simple test kit prepared using filter paper. The kit showed a possible naked-eye detection with a notable color change, and when checked, the aluminium ion detected test kit under a UV lamp showed blue fluorescence.

A pyridine based Schiff base as a selective and sensitive fluorescent probe for cadmium ions with “turn-on” fluorescence responses

A pyridine based Schiff base probe (PMPA) showed high selectivity and sensitivity towards Cd2+ ions with intense bluish green fluorescence. The sensing mechanism of probe PMPA for detecting Cd2+ was based on the inhibited PET and CHEF processes.

Development of a fluorescent probe for detecting Al3+ in cooked wheaten food based on phosphonic acid group functionalized polythiophene derivatives

As an unnecessary trace element, the content of aluminium in biological systems should be strictly controlled. Therefore, it was necessary to develop a convenient method for detection of aluminium ions. In this study, a fluorescent probe based on polythiophene derivatives was developed and used to detect Al³⁺ in Chinese traditional pasta. The fluorescence of this probe showed a significant decrease in hexamethylenetetramine-HCl buffer solution (pH 5) when Al³⁺ was present. In addition, the probe exhibited good sensitivity and selectivity to Al³⁺ over other metal ions when EDTA was used as the masking agent. Fluorescence intensity had a good linear relationship with the Al³⁺ concentration in the range 0.1-10 μM and the limit of detection for Al³⁺ was 39 nM. Furthermore, the probe was successfully applied to detect Al³⁺ in food samples and the results were consistent with ICP-AES.

A novel quinoline-based turn-on fluorescent probe for the highly selective detection of Al (III) and its bioimaging in living cells, plants tissues and zebrafish

A novel quinoline fluorescent probe QNP ((E)-N'-(5-chloro-2-hydroxybenzylidene) quinoline-2-carbohydrazide) for detection of Al3+ ion was designed, synthesized and characterized. QNP displayed a high fluorescence enhancement in the presence of Al3+ ion in DMF:PBS (99:1, v/v) solution and the detection limit was as low as 1.25 μM with high selectivity and excellent sensitivity from 0 to 3 μM. The sensing ability of QNP towards Al3+ ion is attributed to the synergistic effect of PET and ICT. Furthermore, the binding stoichiometry between QNP and Al3+ ion is of 1:1 by Job's plot and mass spectrum, and the calculated binding constant is 4.29 × 108 M-1. The detection of Al3+ ion in water samples illustrates that QNP could be applied to the detection of practical samples in the environment. Bioimaging experiments on Hela cells, zebrafish and soybean root tissues demonstrate that it has potential application to investigate biological processes involving Al3+ ion within living cells. A quinoline-based turn-on fluorescence probe for the detection of Al3+ and its bioimaging in living cells, plant, and zebrafish.

A red luminescent Eu3+ doped conjugated microporous polymer for highly sensitive and selective detection of aluminum ions

A Eu³⁺ doped-CMP composite can be used as a chemosensor for highly sensitive and selective detection of Al³⁺.

AIEgens: An emerging fluorescent sensing tool to aid food safety and quality control

As a global public health problem, food safety has attracted increasing concern. To minimize the risk exposure of food to harmful ingredients, food quality and safety inspection that covers the whole process of "from farm to fork" is much desired. Fluorescent sensing is a promising and powerful screening tool for sensing hazardous substances in food and thus plays a crucial role in promoting food safety assurance. However, traditional fluorphores generally suffer the problem of aggregation-caused quenching (ACQ) effect, which limit their application in food quality and safety inspection. In this regard, luminogens with aggregation-induced emission property (AIEgens) showed large potential in food analysis since AIEgens effectively surmount the ACQ effect with much better detection sensitivity, accuracy, and robustness. In this contribution, we review the latest developments of food safety monitoring by AIEgens, which will focus on the molecular design of AIEgens and their sensing principles. Several examples of AIE-based sensing applications for screening food contaminations are highlighted, and future perspectives and challenges in this emerging field are tentatively elaborated. We hope this review can motivate new research ideas and interest to aid food safety and quality control, and facilitate more collaborative endeavors to advance the state-of-the-art sensing developments and reduce actual translational gap between laboratory research and industrial production.

A highly selective aggregation-induced emission fluorogen for sensitive detection of Al3+ in living cells

A Schiff's base derivative was synthesized using a condensation reaction between 8-formyl-7-hydroxy-4-methylcoumarin and furan-2-carbohydrazide that produced marked aggregation-induced emission and had excellent ability to specifically recognize aluminium ions (Al³⁺ ). This compound displayed faint fluorescence in the benign solvent dimethyl formamide, and exhibited obvious green fluorescence following addition of specific amounts of water. Moreover, it exhibited strong blue fluorescence after combination with Al³⁺ even in the presence of other interfering ions. These experimental results demonstrated that this derivative could be used as a fluorescence probe for Al³⁺ . The advantages, including significant fluorescence change, high selectivity and sensitivity, and fast response, meant that this probe could be used both to detect Al³⁺ in water samples and for fluorescence imaging in living cells.

A dual functional fluorescent sensor for the detection of Al3+ and Zn2+ in different solvents

A new fluorescent sensor, X, was designed and synthesized based on imidazo[2,1-b]thiazole and 2-hydroxy-1-naphthaldehyde, which could be used to detect Al³⁺ in methanol buffer solution and detect Zn²⁺ in ethanol buffer solution, respectively.