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BODIPY derivatives have often been employed as fluorescent sensors to probe toxic ions in environment and living systems, such as sulfide ion (S 2- ). Whilst many structure modifications have been exploited on groups at the 3, 5, 8-positions, there are quite few examples on tailoring the 2,6-substituents for chemosensor investigations. Herein, we design and synthesize a 2,6-substituted BODIPY molecule, LM-BDP, to use as a fluorescent probe for detecting S 2- in aqueous media. The electronic and crystal structures of the probe are studied by density functional theory (DFT) calculations and single-crystal X-ray diffraction analysis. Spectroscopy investigations are performed in a variety of conditions, showing that LM-BDP exhibits a noticeable color change from pink to dark red and a fluorescence shift from yellow to pink channel with decreased intensity upon addition of S 2- . The selectivity and sensitivity measurements show that LM-BDP can only response to S 2- with a detection limit of 0.29 μM in less than 100 s. The remarkable contrast in fluorescence images in test-stripe and RAW 264.7 cell experiments indicates that the probe is a proper candidate for the application in detecting exogenous S 2- ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Herein, a novel fluorometric-sensor with dual-emission system was constructed on the basis of polyvinylpyrrolidone (PVP) and 2-mercaptobenzothiazole (MBT) co-functionalized gold/copper nanoclusters (PVP/MBT-Au@CuNCs) by a facile and eco-friendly one-pot approach. The sensor exhibited ratiometric fluorescence emission (F 590 nm /F 422 nm ) for visual and selective detection of S 2- with a sensitive detection limit of 11.9 nM. Besides, fluorescence quenched sensing of S 2- was chalked up by a quickly selectivity monitoring time of 30 s, owing to the strongly binding of Cu 2 S and Au 2 S by hard-soft-acid-base theory and the destruction of the aggregated structure of PVP/MBT-Au@CuNCs. Furthermore, the platform also provided the portable analysis for visual detection of S 2- by capturing the change in fluorescence color with a single dual-emissive ratiometric paper strip. It is worth mentioning that the fluorescent gold-copper nanoclusters showed excellent application activities in the selective detection of S 2- in Radix Codonopsis or Tremella samples and recognition of S 2- in HeLa cells or macrophages by confocal microscopy fluorescent imaging. Overall, the sensing system paved a new avenue for effectively developing a convenient ratiometric fluorescent sensor platform for evaluating the safety of food with S 2- pollution in environment and biological system., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A new chemosensor based on the thiazolylazo-quinazolinone hybrid (TAQH) was designed and synthesized for naked-eye sensitive detection of F - and S 2- in aqueous acetonitrile solution. Spectral characterization of TAQH using FT-IR, 1 H NMR, and 13 C NMR analysis revealed that the probe TAQH was successfully synthesized using a two steps reaction, including the diazotization-coupling and condensation reactions, respectively. The ion sensing ability of TAQH toward a wide range of anions and metal ions was evaluated by naked-eye detection method and UV-Vis absorption spectroscopy. The chemosensor TAQH displayed a fast and clear color change from yellow to red in the presence of F - and S 2- ions, enabling easily detect with the naked eye. This clear color change is due to the effective interaction of the basic F - and S 2- anions with hydroxyl group of chemosensor as a binding site. The experimental data also revealed that the F - and S 2- ions were sensed by the probe TAQH over a wide pH range from 3 to 8. The results also confirmed that the TAQH has a wide linear detection range for F - and S 2- ions. From UV-vis titration experiment, the limit of detection (LOD) for F - and S 2- ions was found to be 3.1 μM and 5.7 μM, respectively. For quantitative measurements, the paper test strips containing TAQH were successfully fabricated and applied to detect F - and S 2- ions in aqueous solutions. Furthermore, Job's plot based on spectroscopic data showed one-to-one stoichiometry for the interaction of anions with probe TAQH. Therefore, the proposed chemosensor with excellent features like the cost-effective, high sensitively and selectively and short response times can be utilized in any physical and biological conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this paper, Bio-MOF-1 is prepared as reported and then Eu 3+ is introduced into it via cation exchange method. A FAM-labeled ssDNA is chosen to fabricate with the obtained Eu 3+ @Bio-MOF-1. A luminescent hybrid material is assembled, which can exhibit the fluorescence of Eu 3+ and FAM simultaneously by adjusting the ratio of FAM-ssDNA and Eu 3+ @Bio-MOF-1. The sample is then used for the detecting of metal ions, results shows which has good selectively for Cu 2+ (LOD = 0.14 μM, 0-250 μM). The introduction of Cu 2+ can quench the fluorescence of FAM while the luminescent intensity of Eu 3+ enhancing. After the detection of Cu 2+ , the Cu 2+ involved hybrid system can then be further employed for the detection of S 2- (LOD = 1.3 μM, 0-50 μM). Low concentration of S 2- can make the luminescent intensity of Eu 3+ decrease gradually while high concentration of S 2- can further recover the luminescent of FAM, which is quenched by Cu 2+ ., (Copyright © 2017 Elsevier B.V. All rights reserved.)

We demonstrate an advance in the fabrication of circular dichroism (CD) sensors for detection of Cd 2+ and S 2- based on chiral CdS quantum dots (QDs) generated by a facile in-situ reaction. The chiral quantum dots are generated in solutions composed of Cd 2+ , S 2- , cysteamine (CA) and L-penicillamine (L-PA), with the number of the generated particles limited by either the Cd 2+ or S 2- concentration. We show that the magnitude of the CD signal produced by the QDs is linearly related to the initial concentration of Cd 2+ and S 2- , with excellent selectivity over other ions. Our sensor functions over concentration ranges of 65-200μM and 7-125μM with detection limits of 59.7 and 1.6μM for Cd 2+ and S 2- , respectively. The sensor is applied in real water samples with results comparing favorably with those obtained from ICP-OES (for Cd 2+ ) and HPLC (for S 2- )., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this paper, green curcumin nanoparticles (CURNs) are introduced for colorimetric sensing of sulfide using micelle mediated cloud point extraction for the first time. CURNs are transferred into non-ionic surfactant phase and show strong surface plasmon absorption intensity. The extraction of CURNs to the surfactant rich phase is suppressed in the presence of Cu(2+) but upon addition of sulfide, the extraction of CURNs to the surfactant rich phase is increased again. This increase in the absorbance of surfactant rich phase is related to the sulfide concentration and was used as an analytical signal for the sensing of sulfide. The effect of chemical variables such as pH of the sample solution, concentration of Cu(2+), electrolyte and CURNs on the cloud point extraction was studied. Under optimum conditions, the change in absorption intensity was linearly proportional to the concentration of sulfide in the range of 0.5-200.0 ng mL(-1) with a detection limit of 0.4 ng mL(-1). The relative standard deviations for 10 replicate measurements of 20 ng mL(-1) and 175 ng mL(-1) of sulfide were 4.1% and 1.4% respectively. The method was successfully applied to the determination of sulfide in different water samples., (© 2013 Published by Elsevier B.V.)