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Cyanide is a highly toxic anion. Nonetheless, many food plants could produce endogenous cyanide, which causes great danger to human health. Thus, monitoring cyanide in food samples is critically significant. Herein, we rationally developed the first ratiometric near-infrared fluorescent probe for sensing cyanide in food samples. The probe displayed noticeable fluorescence in near-infrared region. Moreover, upon treatment with cyanide, the probe exhibited highly selective and sensitive ratiometric fluorescence response, with limit of detection determined to be 0.075 μM and limit of quantification determined to be 0.25 μM. The ratios of fluorescent intensities at 519 and 688 nm (I 519 /I 688 ) was linear with added cyanide concentrations from 0 to 80 μM. The relative standard deviations for repeatability and reproducibility varied from 0.55 to 8.94 and from 1.17 to 9.46, respectively. Significantly, probe Hy has been successfully applied for monitoring cyanide in various food samples, such as almonds, sprouting potatoes, and bamboo shoots., 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 Ltd. All rights reserved.)

Development of an efficient fluorescent probe for sensing hypochlorite in water samples and biological samples is highly demanded. However, the currently reported fluorescent probes for hypochlorite frequently suffered from the problem of high background fluorescence. Herein, based on the combined effect of two different fluorescence quenching groups, we rationally developed a novel fluorescent probe for hypochlorite with extremely low background fluorescence. Notably, due to the doubly quenching groups, the probe could even keep low background fluorescence in a solution with high viscosity. Furthermore, the probe displayed highly sensitive and selective response to hypochlorite, with the detection limits calculated to be 10.5 nM. Practical application demonstrated that the probe was able to quantitatively detect hypochlorite in various water samples with good recovery. Significantly, the probe showed extremely low background fluorescence in living cells and was capable of detecting minor variation of endogenous hypochlorite in RAW 264.7 cells. Moreover, the fluorescence imaging different concentration of hypochlorite in zebrafish has been successfully conducted. The probe developed herein will be widely used as a reliable tool to accurately monitor the variation of hypochlorite in living organism., Competing Interests: Declaration of competing interest There are no conflicts to declare., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Hypochlorite (ClO - ) and singlet oxygen ( 1 O 2 ) commonly coexist in living systems and exert important interplaying roles in many diseases. To dissect their complex inter-relationship, it is urgently required to construct a fluorescent probe that can discriminate ClO - and 1 O 2 in living organisms. Herein, by taking the 3-(aliphaticthio)-propan-1-one group as the unique recognition unit for both ClO - and 1 O 2 , we proposed the first fluorescent probe, Hy-2 , to simultaneously discriminate ClO - and 1 O 2 with high sensitivity and selectivity. Probe Hy-2 itself showed fluorescence in blue channel. After treatment with ClO - and 1 O 2 , respectively, pronounced fluorescence enhancements were observed in the green channel and red channel correspondingly. Moreover, upon development of the probe with aggregation-induced emission (AIE) characteristics, the probe could work well in a solution with high water volume fraction. Probe Hy-2 was also able to accumulate into mitochondria and was utilized as an effective tool to image exogenous and endogenous ClO - and 1 O 2 in mitochondria. Significantly, as the first trial, probe Hy-2 was employed to simultaneously monitor the variation of ClO - and 1 O 2 level in cecal tissues of rat in the cecal ligation and puncture (CLP)-induced polymicrobial sepsis model. The results demonstrated that the expressed ClO - and 1 O 2 levels were tightly correlated with the severity of sepsis, inferring that the overproduction of ClO - and 1 O 2 is an important factor in the pathogenesis of sepsis. The probe illustrated herein may provide a guide for further exploring the functions of ClO - and 1 O 2 in various diseases.

Monitoring cyanide levels in water and food samples is crucial. Herein, we rationally developed a simple and efficient fluorescent probe for cyanide determination. The probe displayed selective ratiometric fluorescent response to cyanide. In addition, after treatment with cyanide, the fluorescence ratios ( I 509 / I 466 ) exhibited a good linearity with cyanide concentration in the range of 0-60 μM, and the detection limit was determined to be 0.23 μM ( S / N = 3). Significantly, the practical application demonstrated that the probe was able to quantitatively detect cyanide concentration in natural water samples. Monitoring of endogenous cyanide in cherry nut by the probe was also successfully conducted. Notably, upon fabrication of test strips, the probe could be conveniently utilized for field measurement of cyanide in bitter almond without relying on sophistical instruments. Furthermore, the cyanide in potato tissues was determined for the first time by means of fluorescence imaging., Competing Interests: The authors declare no competing financial interest.

A novel chemiluminescence immunoassay based on luminol-modified gold nanoclusters (AuNCs@Peps@luminol) was developed for simultaneous detection of tetrabromobisphenol A bis(2-hydroxyethyl) ether (TBBPA-DHEE) and tetrabromobisphenol A mono(hydroxyethyl) ether (TBBPA-MHEE), an important derivative and byproduct of tetrabromobisphenol A (TBBPA), respectively. In the system, alkaline phosphatase (ALP) was labeled on the second antibody (Ab 2 ) for signal amplification. When ALP-Ab 2 was captured by antigen-primary antibody (Ab 1 ) complex, disodium phenyl phosphate (PPNa) generated massive phenol under the catalysis of ALP, markedly inhibiting the chemiluminescence intensity of AuNCs@Peps@luminol. Under the optimized conditions, the calculated detection of limit (LOD, 90% inhibition) was 0.078 μg/L for TBBPA-DHEE with a linear range of 0.23-9.32 μg/L, which was lower 9 times than that of conventional ELISA with the same antibody. In addition, our method showed satisfactory accuracy and precision (recoveries, 88.00-113.4%; CV, 2.75-8.14%), it can be applied to systematically investigate the concentration of the trace TBBPA-DHEE and TBBPA-MHEE in environmental and food samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A sensitive and artful colorimetric immunosensor based on horseradish peroxidase (HRP) was designed by labelling metal-organic frameworks (Cu-MOFs) on the second antibody (Cu-MOFs@Ab 2 ) as signal amplification for the detection of trace dibutyl phthalate (DBP). In this system, when Cu-MOFs@Ab 2 was captured by antigen- primary antibody (Ab 1 ) complex, tremendous Cu(II) will be released from Cu-MOFs in the presence of nitric acid (HNO 3 ), and Cu(II) will be further reduced to Cu(I) after the addition of sodium ascorbate (SA), consequently, inhibiting the HRP to catalyse the colorless 3,3',5,5'-tetramethylbenzidine (TMB) into blue oxidized TMB (ox TMB). Under the optimized conditions, the limit of detection (LOD) was 1 μg L -1 , which was almost 60 times lower than that using a conventional ELISA with the same antibody. In addition, our method showed good accuracy and reproducibility (recoveries of 87.73-103.4%; CV values of 1.46-5.95%) through a spike-recovery analysis. The proposed immunosensor indicated great potential for trace DBP determination from environmental and food samples., (Copyright © 2018. Published by Elsevier B.V.)

In this work, hollow carbon nanospheres (HCNS) were prepared, followed by the introduction of gold nanoparticles (AuNPs) on the HCNS surface, and then functionalization with per-6-thio-β-cyclodextrin (CD) based on the formation of "Au-S" bond, resulting in a novel cyclodextrin/carbon-based nanohybrid (CD-AuNPs/HCNS), which possesses the unique properties of HCNS (excellent electrochemical properties and large surface area), CD (high host-guest recognition and water-solubility) and AuNPs (excellent electrocatalytic activity). The obtained CD-AuNPs/HCNS nanohybrids were characterized by scanning electron microscopy, transmission electron microscopy, inductively coupled plasma-atomic emission spectroscopy, Fourier transform infrared spectroscopy and electrochemical methods. Furthermore, CD-AuNPs/HCNS were applied in the simultaneous electrochemical sensing of o-dihydroxybenzene (o-DHB) and p-dihydroxybenzene (p-DHB) (both o- and p-DHB have similar structures and coexist in environment; moreover, they are toxic to humans and difficult to degrade). Under the optimum conditions, the detection limits of o- and p-DHB obtained in this work are 0.01 and 0.02 μM, respectively.

Herein, two compounds (1 a and 1 b) were rationally constructed as novel reaction-based fluorescent probes for CN(-) by making use of the electron-withdrawing ability of the cyano group that was formed from the sensing reaction. Notably, this design strategy was first employed for the development of fluorescent CN(-) probes. The experimental details showed that probe 1 a exhibited a fluorescence turn-on response to CN(-), whereas other anions, biological thiols, and hydrogen sulfide gave almost no interference. The detection limit of probe 1 a for CN(-) was found to be 0.12 μM. The sensing reaction product of 1 a with CN(-) was characterized by NMR spectroscopy and mass spectrometry. TD-DFT calculations demonstrated that the formed cyano group drives the intramolecular charge transfer (ICT) process from coumarin dye to the cyano group and thus the original strong ICT from the coumarin dye to the 3-position pyridyl vinyl ketone substituent is weakened, which results in recovery of coumarin fluorescence. The practical utility of 1 a was also examined. By fabricating paper strips, probe 1 a can be used as a simple tool to detect CN(-) in field measurements. Moreover, probe 1 a has been successfully applied for quantitative detection of endogenous CN(-) from cassava root., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Being awfully harmful to the environment and human health, the qualitative and quantitative determinations of polycyclic aromatic amines (PAAs) are of great significance. In this paper, a novel core-shell heterostructure of multiwalled carbon nanotubes (MWCNTs) as the core and graphene oxide nanoribbons (GONRs) as the shell (MWCNTs@GONRs) was produced from longitudinal partially unzipping of MWCNTs side walls using a simple wet chemical strategy and applied for electrochemical determination of three kinds of PAAs (1-aminopyrene (1-AP), 1-aminonaphthalene and 3,3'-diaminobiphenyl). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis and electrochemical methods were used to characterize the as-prepared MWCNTs@GONRs. Due to the synergistic effects from MWCNTs and GONRs, the oxidation currents of PAAs at the MWCNTs@GONRs modified glassy carbon (GC) electrode are much higher than that at the MWCNTs/GC, graphene/GC and bare GC electrodes. 1-AP was used as the representative analyte to demonstrate the sensing performance of the MWCNTs@GONRs/GC electrode, and the proposed modified electrode has a linear response range of 8.0-500.0 nM with a detection limit of 1.5 nM towards 1-AP., (Copyright © 2014 Elsevier B.V. All rights reserved.)