Recent progress in the small-molecule fluorescent probes for the detection of sulfur dioxide derivatives (HSO3-/SO32-).

Recent advances in chromo-fluorogenic probes for fluoride detection

Sulfite (SO32−) and bisulfite (HSO3−) have been widely used in food preservation to avoid oxidation and microbe growth and inhibit enzymatic reactions. Extensive intake of SO32−/HSO3− will cause allergic reactions and even tissue damages in some individuals. Therefore, developing responsive small-molecule probes for rapid, effective, and quantitative detection of SO32−/HSO3− in various foods has attracted increasing attentions in recent years. Based on different response mechanisms, such as nucleophilic addition with the electron deficit “C C” bonds, ketone or aldehyde groups, and inhibition of C N isomerization, a number of responsive small-molecule probes have been developed for food analysis. This review focuses on the progress in the development of responsive small-molecule probes for SO32−/HSO3− analysis in food samples. Their chemical structures, response mechanisms with SO32−/HSO3−, and performance for SO32−/HSO3− analysis in food samples are summarized and discussed. The future research directions for developing novel probes for SO32−/HSO3− analysis in food samples are proposed.

Responsive small-molecule luminescence probes for sulfite/bisulfite detection in food samples

Chemodosimeters for optical detection of fluoride anion

Recent advances (2017–20) in the detection of copper ion by using fluorescence sensors working through transfer of photo-induced electron (PET), excited-state intramolecular proton (ESIPT) and Förster resonance energy (FRET)

A novel probe based on rhodamine 101 spirolactam and 2-(2'-hydroxy-5'-methylphenyl)benzothiazole moieties for three-in-one detection of paramagnetic Cu2+, Co2+ and Ni2.

A novel fluorescent turn-on probe (compound 1) for bisulfite based on 7-nitrobenz-2-oxa-1,3-diazole (NBD) chromophore has been developed. Its sensing behavior toward various anions was investigated by absorption and fluorescence techniques. This probe shows a selective, turn-on fluorescent response and ratiometric colorimetric response toward bisulfite in aqueous acetonitrile solutions. The possible recognition mechanism of probe 1toward bisulfite was illustrated by MS spectra analysis and DFT calculations Probe 1 was used to determine bisulfite in real-life samples with good recoveries.

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A novel fluorescent turn-on probe for bisulfite based on NBD chromophore

A new chemodosimeter based on dicyanomethylene-4H-chromene chromophore (probe 1) was developed as a ratiometric fluorescent probe in near-infrared range for F− with good selectivity in acetonitrile. Probe 1 could be used to directly visualize F− by the naked eye and showed more than 621-fold fluorescence enhancement at 715 nm upon reaction with F− upon excitation at 625 nm. The recognition of probe 1 to fluoride was featured by F−-induced red-shifts of both absorption (185 nm) and fluorescence peaks (132 nm) based on internal charge transfer (ICT) in acetonitrile. The desilylation reaction of 1 by F− was proposed for its dual absorption and emission ratiometric detection of fluoride.

A near-Infrared Fluorescent Chemodosimeter for Ratiometric Detecting Fluoride Based on Desilylation Reaction

A new near-infrared fluorescent “turn-on” chemodosimeter (probe 1) based on dicyanomethylene-4H-chromene fluorophore for sulfide was developed. Probe 1 showed good fluorescence selectivity to sulfide over other anions and thiol-containing compounds. The discrimination of sulfide from disulfide could be achieved by comparison of the spectral difference of probe 1 after interaction with them. The absorption of probe 1 at 437 nm decreased, accompanied by red-shifting to 470 nm as a shoulder, and a strong peak at 610 nm appeared in the presence of sulfide. The absorption of 1 was slightly red-shifted to 452 nm with increased absorbance in the presence of disulfide. Probe 1 showed more than 1000-fold fluorescence enhancement at 712 nm with a Stokes shift of 102 nm in the presence of sulfide. The probe exhibited a good sensitivity in detection of sulfide with a wide pH span (4.0–11.0). The absorption change and fluorescence enhancement could be attributed to thiolysis of the dinitrophenyl ether group in probe 1 by the sulfide. The proposed mechanism was proved by 1H NMR spectra and EI-MS explorations. The probe was successfully applied for the detection of sulfide anions in real water samples.

A new near-infrared fluorescent chemodosimeter for discrimination of sulfide from disulfide

A new fluorescent probe (probe 1) was developed for recognition of cysteine (Cys) and homocysteine (Hcy). Probe 1 exhibited a large absorption peak blue-shift (107 nm) as well as enhanced fluorescence responses to Cys/Hcy based on cyclization of thiol containing amino acids with aldehydes, inhibiting the C = N isomerization-induced quenching process by an intramolecular hydrogen bond. The detection mechanism was proved by (1)H NMR and mass spectrometry analysis.

Guangqin Gao

Papers

A novel probe based on rhodamine 101 spirolactam and 2-(2'-hydroxy-5'-methylphenyl)benzothiazole moieties for three-in-one detection of paramagnetic Cu2+, Co2+ and Ni2.

A novel fluorescent turn-on probe for bisulfite based on NBD chromophore

A near-Infrared Fluorescent Chemodosimeter for Ratiometric Detecting Fluoride Based on Desilylation Reaction

A new near-infrared fluorescent chemodosimeter for discrimination of sulfide from disulfide

A New Turn on Fluorescent Probe for Selective Detection of Cysteine/Homocysteine