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Synthesis of photoluminescence carbon dots from red beetroot and utilizing its extract for spectrofluorimetric determination of tenoxicam. [Display omitted] • Photoluminescence carbon dots were synthesized for the first time from red beetroot. • The fluorescence intensity of the carbon dots was quenched by adding tenoxicam. • The acetonitrile extract of red beetroot exhibits fluorescence activity. • The fluorescence intensity of the extract was enhanced by adding tenoxicam. • The developed methods were applied to determine tenoxicam in different dosage forms. Tenoxicam (TNX) belongs to non-steroidal drugs that effectively treat many inflammatory disorders. In this study, luminescent carbon dots were synthesized from red beetroot as a green fluorescence probe. The synthesized carbon dots' morphology, size, and spectroscopic features were investigated and characterized by spectrophotometric, FTIR, SEM, spectrofluorimetric, and TEM techniques. The synthesized carbon dots possessed an emission at 430 nm and an excitation at 366.5 nm. Meanwhile, TNX is a yellow-colored compound with a spectrophotometric absorbance peak at 370 nm. Based on the inner filter effect mechanism, the emission fluorescence intensity of the synthesized carbon dots has been markedly quenched upon the addition of TNX. In addition, the quenching in the fluorescence intensity was quantitively related to the concentration of TNX at the linear range of 0.25 - 2.5 µg/mL (r2 = 0.9989) with a LOD of 0.08 µg/mL and LOQ of 0.24 µg/mL. The second side of this study is based on enhancing the fluorescence intensity of the acetonitrile extract of red beetroot upon the addition of TNX solution. This enhancement was recorded at a fluorescence emission of 357 nm with a fluorescence excitation of 305.5 nm. In addition, the enhancement in the fluorescence intensity was quantitively related to the concentration of TNX at the linear range of 0.5 - 8.0 µg/mL (r2 = 0.9995) with a LOD of 0.16 µg/mL and LOQ of 0.49 µg/mL. The analytical conditions were well-optimized, and the developed method was validated according to ICH guidelines. Finally, the proposed spectrofluorimetric approaches were applied to determine TNX in vials, tablets, and capsules with good recovery and accepted statistical results. [ABSTRACT FROM AUTHOR]

[Display omitted] • The sensor is highly sensitive and selective to Hg2+ with low detection limit. • The sensor provides five cycles–reversibility for Hg2+ detection. • The sensor offers a very large Stokes shift of 192 nm. • The sensor enables for quick screening of Hg2+ in water and cosmetic samples. • Application in the potential Hg2+–accumulated human cells is demonstrated. Mercury pollution and its toxicity pose a grave threat to health. Therefore, developing new approaches for detecting mercury ions (Hg2+) in environmental and biological samples is crucial. Herein, a novel [5]helicene-based fluorescence sensor (M201NHP) was designed and synthesized for rapid, sensitive and specific detection of Hg2+. The sensor exhibits fluorescence quenching with a very large Stokes shift (192 nm) towards Hg2+ in aqueous acetonitrile media. The detection limit of the sensor is estimated to be 1.94 ppb, which is lower than the U.S. EPA specification for the maximum Hg2+ level in drinking water. Moreover, M201NHP offers five cycles of reversibility upon competitive chelation of cysteine. The sensor can also screen for Hg2+ contamination in real water samples and skincare products. Additionally, it can track Hg2+ in potential mercury-accumulated human cell lines derived from brain tumours, embryonic kidneys, skin and liver cancers with low cytotoxicity. These results indicate that M201NHP is a promising Hg2+ sensor that can prevent health risks and environmental impacts caused by mercury pollution. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new BODIPY derivative 1 behaves as an “on–off” fluorescent sensor of Cu2+. [•] Complex 1·Cu 2+ displays “off–on” fluorescent spectral response to biothiols and S2−. [•] 1·Cu 2+ complex can better recognize glutathione compared with cysteine and homocysteine. [•] 1 exhibits high sensitivity for Cu2+ under physiological conditions and in living cells. [•] 1 can locates in lysosome used as fluorescent dye in cell imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • The probe was designed and synthesized based on a rhodol derivate anchored with the 2,4-dinitrophenyl group. • The fluorescent response was fast within 12 min and a dramatic color change (from colorless to pink) could be observed by naked eyes. • The detection limit of the probe was 0.097 μM. • The probe was successfully applied to detecting H 2 S in real water samples and HeLa cells. In this work, a reaction-based fluorescence turn-on probe RCHO, a rhodol derivate anchored with the 2,4-dinitrophenyl moiety, was designed and synthesized for H 2 S detection. The 2,4-dinitrophenyl moiety, as an electron-withdrawing group, was used for quenching the fluorescence of the fluorophore. The probe RCHO could quantitively detect H 2 S with high selectivity and fast response by introducing aldehyde groups in the ortho position of 2,4-dinitrobenzene. After addition of H 2 S, H 2 S was quickly added to the aldehyde group through a nucleophilic addition reaction, and then the dinitrophenyl ether underwent effective intramolecular thiolysis, which resulting in the release of the fluorophore and a rapid fluorescence turn-on response. The detect limit was calculated to be 0.097 μM. Furthermore, in the presence of H 2 S, a remarkable color change from colorless to pink was observed, indicating that the probe RCHO could monitor H 2 S by the naked eyes. More importantly, the probe could be used as a highly efficient tool for H 2 S detection in living cells and environmental water. [ABSTRACT FROM AUTHOR]

[Display omitted] • A newly developed Chemosensor HL for effective detection of Zn(II) with the formation of complex 1 in presence of azide. • The fluorescence microscopic images of normal HEK cell assures the biomedical application of HL towards Zn(II) • Complex 1 haven been further utilized for easy detection of Al(III) ion with the formation of Zn-Al bimetal complex • An INHIBIT logic circuit is formed with two step sensing phenomena along with the formation of a molecular memory A schiff base chemosensor HL [4-chloro-(((2-(piperidine-1-yl)imino)methyl)phenol], constructed by one step condensation of 2-aminoethyl piperidine and 5- Chloro Salicylaldehyde is illustrated to have its usefulness for selective and sensitive detection of Zn(II) among other metal ions in aqueous solution (HEPES buffer) displaying the colour changes from light blue to turquoise under UV light. The specific detection phenomena of Zn (II) is monitored by the remarkable fluorescence enhancement and notable change in NMR spectral data of fluorescence active HL after addition of Zn(II) to it. The impressive high binding constant in 106 orders, determined by electronic spectral titration after introduction of Zn(II) to HL assure the formation of a Zinc complex during sensing phenomena. In order to check whether the nuclearity of the constructed complex can be increased or not fluorescence enhancement phenomenon is further monitored in presence of different bridging ligands and the results display that only in presence of azide a significant enhancement of Zn(II)- HL domain is exposed where as for other bridging ligand the spectra remain unaltered. This observation insists to conduct the reaction between HL and ZnCl 2 in presence of sodium azide which lead the formation of a Zn complex [Zn 2 (HL) 2 (N 3) 4 (complex 1) employing azide as the secondary anionic residue instead of bridging. The single crystal structure of the complex unveils the unique protonation of the piperidine N during the crystallization of the dinuclear motif of the complex 1. Furthermore the Zn complex due to the presence of remarkable luminescence property have been effectively used for selective sensing of Al(III) ion as metalloreceptor in HEPES buffer solution via turn of fluorescence with remarkable fluorescence quenching constant. In aqueous solution, complex 1 induces a 1:2 complex formation with Al(III) ion indicated by Job's plot analysis. The DFT study suggests the formation of bimetal complex during sensing of Al(III) with complex 1 as metalloreceptor. The in vitro cell imaging study gives a authentic hints for in vivo biomedical application of HL as a selective and easy Zn(II) sensor. The two step sensing phenomena of HL and complex 1 is further established by advanced molecular logic gate formation. [ABSTRACT FROM AUTHOR]