A new carbazole based fluorescent probe with AIE characteristic for detecting and imaging hydrazine in living cells, mungbean sprouts, Arabidopsis thaliana, and practical samples

In this study, we report a new carbazole-malononitrile fluorescent probe CBC with an interesting aggregation-induced emission (AIE) characteristic. Probe CBC could rapidly and selectively detect hydrazine (N2H4) in ～100% aqueous media, and also exhibit an exceedingly low detection limit of 6.3 nM for sensitively detecting N2H4. The sensing mechanism of CBC towards N2H4 has been well demonstrated through the spectra of 1H NMR, HRMS and FTIR. Interestingly, probe CBC was applied to visualize and detect gaseous and aqueous N2H4 with sensitive color changes. Importantly, probe CBC was applied to effectively detect N2H4 in practical samples such as soil, human serum, human urine, plants, foods and beverages, as well as sensitively sense and image N2H4 in biological systems including living mungbean sprouts, Arabidopsis thaliana, and HeLa cells.

TICT fluorescent probe for Al3+: Sequential detection of PPi, ATP and ADP in semi-aqueous medium and real-life applications

A ditopic Schiff base ligand, H₂L has been synthesized and characterized by all spectroscopic techniques. It is highly selective and specific towards Al³⁺ in semi aqueous medium (DMF/H₂O mixture) by exhibiting a drastic increase in the fluorescence intensity. The emission studies, spectroscopic data, life time and quantum yield results have been used to understand its binding mode, explore its specificity and establish its efficacy. The intensity difference is remarkable in physiological pH range. Due to its reversible behavior this ditopic fluorescent chemosensor can be used multiple times to make it cost effective. Detection limit for this chemosensor was found to be 0.65 μM. Experiments with TLC plates show that it can be used as a practical and portable sensor for studying environmental samples in real life. The L-Al³⁺ complex generated in the solution acts as a sensor to sequentially detect pyrophosphate groups present in inorganic pyrophosphates, ATP and ADP among other anions by turning off the fluorescence. Inhibit logic gate and its corresponding truth table has been developed to aid in further exploiting its multidimensional applications.

Red-Emission Probe for Ratiometric Fluorescent Detection of Bisulfite and Its Application in Live Animals and Food Samples

Key roles of bisulfite (HSO3 -) in food quality assurance and human health necessitate a reliable analytical method for rapid, sensitive, and selective detection of HSO3 -. Herein, a new red-emitting ratiometric fluorescence probe, BIQ, is reported for sensitive and selective detection of HSO3 - in food samples and live animals. Probe BIQ recognizes HSO3 - via a 1,4-nucleophilic addition reaction. As a result of this specific reaction, emission intensities at 625 and 475 nm are dramatically changed, allowing the detection of HSO3 - in a ratiometric fluorescence model in an aqueous solution. The obvious changes of solution color from pink to transparent and fluorescence color from rose-red to cyan allow the detection of HSO3 - by naked eyes. Furthermore, probe BIQ has fast response in color and fluorescence (<2 min), excellent selectivity, and a low detection limit (0.29 μM), which enables its application in HSO3 - detection in food samples and live organisms. The practical applications of probe BIQ are then demonstrated by the visualization of HSO3 - in live animals (zebrafish and nude mouse) as well as the determination of HSO3 - in white wine and sugar.

A New Red-Emitting Fluorescence Probe for Rapid and Effective Visualization of Bisulfite in Food Samples and Live Animals

The development of new methods for rapid and effective detection of bisulfite (HSO₃^-) in food samples and imaging of HSO₃^- intake in animals is of significant importance due to the key roles of HSO₃^- in food quality assurance and community health. In this work, a new responsive fluorescence probe, EQC, is reported for the quantitative detection of HSO₃^- in food samples and visualization of HSO₃^- intake in animals. Upon addition of HSO₃^-, the UV-vis absorption and red emission of EQC were significantly decreased within 120 s. The changes in absorption and emission spectra of EQC were rationalized by theoretical computations. The proposed reaction mechanism of EQC with HSO₃^- was confirmed by high-resolution mass spectrometry (HRMS) and spectroscopic titration measurements. EQC has the advantages of high sensitivity, selectivity (a detection limit of 18.1 nM), and fast response toward HSO₃^-, which enable rapid and effective HSO₃^- detection in buffer solution. The practical applications of EQC were demonstrated by the detection of HSO₃^- in food samples and the imaging of HSO₃^- intake in live animals.

A simple and highly selective 1,2,4,5-tetrazine-based colorimetric probe for HSO3− ion recognition in food

3,6-Bis-substituted-1,2,4,5-tetrazine-based colorimetric probes, which have good water solubility, could detect bisulfate with high sensitivity and selectivity in food samples.