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In this study, rose bengal‐derived carbon quantum dots (RB‐CQDs) was synthesized by a one‐step solvothermal method using rose bengal and 1,2‐phenylenediamine as precursors in ethanol at 180 °C for 10 h and purified by silica gel chromatography. The as‐synthesized RB‐CQDs disperses well in water with particle sizes ranging from 0.78 to 2.46 nm and exhibits excitation‐independent yellow fluorescent emission (529 nm), high quantum yield (44.3 %) and good biocompatibility. More importantly, the fluorescence of RB‐CQDs can be selectively quenched by Fe3+ ions with good linear correlation and the detection limit is 19.9 nM. The recoveries of this method in actual water samples are 90 % to 110 % with relative standard deviations less than 5 %. [ABSTRACT FROM AUTHOR]

In this work, a selective fluorescent sensor for Hg2+ detection in aqueous solution, which contains a naphthalimide derivative covalently grafted to the glass surface, was developed. To fabricate the sensor, the naphthalimide derivative (compound 1) with a terminal double bond was prepared and photo-copolymerized with 2-hydroxyethyl methacrylate (HEMA) on the glass surface treated with a silanizing agent. Upon binding mercuric ions in 0.05mol/L Tris/HCl (pH 7.01) at 25°C, the resulting optical sensor undergoes fluorescence enhancement. Thus, the proposed sensor with visible excitation can behave as a fluorescent sensor for the selective detection of Hg2+. The fluorescence enhancement was induced by a photo-induced electron transfer (PET) inhibition process. In addition, the proposed sensor showed satisfactory selectivity, reproducibility and response time. The sensing membrane possesses a relatively long lifetime of at least 2 months. The chemosensor can be applied to the quantification of Hg2+ with a linear range covering from 6.0×10–6 to 2.0×10−4 M and a detection limit of 2.0×10−6 M. The determination of Hg2+ in river water samples shows satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: A fluorescent probe 1 for Hg2+ based on a rhodamine–coumarin conjugate was designed and synthesized. Probe 1 exhibits high sensitivity and selectivity for sensing Hg2+, and about a 24-fold increase in fluorescence emission intensity is observed upon binding excess Hg2+ in 50% water/ethanol buffered at pH 7.24. The fluorescence response to Hg2+ is attributed to the 1:1 complex formation between probe 1 and Hg2+, which has been utilized as the basis for the selective detection of Hg2+. Besides, probe 1 was also found to show a reversible dual chromo- and fluorogenic response toward Hg2+ likely due to the chelation-induced ring opening of rhodamine spirolactam. The analytical performance characteristics of the proposed Hg2+-sensitive probe were investigated. The linear response range covers a concentration range of Hg2+ from 8.0×10−8 to 1.0×10−5 molL−1 and the detection limit is 4.0×10−8 molL−1. The determination of Hg2+ in both tap and river water samples displays satisfactory results. [Copyright &y& Elsevier]

Highlights: [•] A fluorescence-based ferric ion-sensing glass slides were described. [•] A naphthalimide derivative was photo-copolymerized on the surface of glass slides. [•] The Fe3+ sensor shows high selectivity in 100% aqueous solution. [•] The sensor exhibits sufficient repeatability, rapid response and long lifetime. [ABSTRACT FROM AUTHOR]

Abstract: A porphyrin derivative (1), containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of metal ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, compound 1 exhibits unexpected ratiometric fluorescence response to Zn2+ with high selectivity. The response of the novel chemosensor to zinc was based on the porphyrin metallation with cooperating effect of 2-(oxymethyl)pyridine units. The change of fluorescence of 1 was attributed to the formation of an inclusion complex between porphyrin ring and Zn2+ by 1:1 complex ratio (K =1.04×105), which has been utilized as the basis of the fabrication of the Zn2+-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Zn2+-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn2+ with a linear range covering from 3.2×10−7 to 1.8×10−4 M and a detection limit of 5.5×10−8 M. The experiment results show that the response behavior of 1 to Zn2+ is pH-independent in medium condition (pH 4.0–8.0) and show excellent selectivity for Zn2+ over transition metal cations. [Copyright &y& Elsevier]

Isochlorogenic acid A(ICA) is the main active component of several TCMs, such as Artemisiae Scopariae Herba. This study aims to identify the metabolites of orally administered ICA in rat plasma, urine, and feces, and to speculate on its potential metabolic pathways. Rats were administered ICA orally, and samples of plasma, urine, and feces were collected at different time points. High-performance liquid chromatography-quadrupole Exactive Orbitrap-mass spectrometry(HPLC-Q-Exactive Orbitrap-MS) was used in combination with reference standards, retention time comparison, fragmentation pattern analysis, and literature data to identify the metabolites in the biological samples. A total of 39 metabolites(M1-M39) of ICA were preliminarily identified from rat samples, including 31 from plasma(M1-M10, M12-M24, M26-M28, M30, M34-M35, M38-M39), 34 from urine(M1-M11, M13-M15, M19-M25, M27-M39), and 11 from feces(M2-M3, M6, M15, M21-M23, M32, M34, M36-M37). The main metabolic pathways included hydrolysis, glucuronidation, methylation, and sulfonation reactions. This study revealed the metabolic profile of ICA in rat plasma, urine, and feces, providing references for the in-depth elucidation of its pharmacologically active components.

In the title mol-ecule, [Fe(C(5)H(5))(C(7)H(6)BrO)], the C atoms of the substituted ring have disparate Fe-C bond lengths compared with the unsubstituted ring. In the bromo-acetyl residue, the Br and O atoms are co-planar [the O-C-C-Br torsion angle is 5.7 (4)°] and are syn to each other. Helical supra-molecular chains along the b axis are formed in the crystal structure mediated by C-H⋯O contacts; the carbonyl-O atom is bifurcated. The chains are linked into layers by C-H⋯π(unsubstituted ring) inter-actions that stack along the a-axis direction.