Journal of Fluorescence最新文献

Dye, a major contaminant from the textile, paper, and pulp industries, is a serious environmental and human health hazard. Because of their low cost, environmental friendliness, and sustainability, semiconductor nanoparticles are among the most effective photocatalysts for detecting dyes in wastewater. Quantum dots (QDs), particularly Carbon quantum dots (CQDs), have received a lot of attention due to their unique optical and electrical properties, making them excellent for applications such as sensing and detection. This paper describes a unique microwave-assisted method for synthesising CQDs in ambient reaction conditions, providing a fast, scalable, and passivation-free alternative to traditional methods. The CQDs were characterised using SEM, XRD, FTIR, UV-Vis spectrophotometry, and photoluminescence, which confirmed their uniform size distribution and outstanding optical characteristics. The CQDs had detection limits of 0.413 ppm for cresol red and 0.847 ppm for cresol purple, indicating great sensitivity and selectivity over a wide pH range. These findings propose a new, sustainable, and cost-effective alternative for tackling water pollution and its detrimental effects on aquatic ecosystems, hence increasing the use of Carbon QDs in environmental restoration.

We have successfully developed a novel thiourea-based chemosensorN-((6-methylbenzo[d]thiazol-2-yl)carbamothioyl)-3,5-bis(trifluoromethyl)benzamide, TS, specifically designed for the detection of Hg²⁺. The structure of TS was comprehensively characterized using techniques such as ¹H NMR, FT-IR, and fluorescence spectroscopy. TS exhibited exceptional fluorescence enhancement in the presence of Hg²⁺ ions when tested against a broad range of metal ions, including Cr³⁺, Co²⁺, Ca²⁺, Na⁺, Pb²⁺, Mn²⁺, K⁺, Ni²⁺, Mg²⁺, Zn²⁺, Cd²⁺, Cu²⁺, Ag⁺, and Al³⁺. The selectivity and sensitivity studies were performed in a MeOH/water (2:98, v/v) solvent system, where TS demonstrated a highly sensitive response to Hg²⁺ ions with a detection limit as low as 0.005 µg/mL. Insights into the sensing mechanism were explained through fluorescence and Job's plot analysis, confirming a robust and efficient detection pathway with a 2:1 binding mode between TS and Hg²⁺. To assess its real-world applicability, recovery experiments were conducted on environmental and agricultural samples spiked with Hg²⁺ ions. The chemosensor achieved impressive recovery rates ranging from 90.0 ± 0.24% to 102.0 ± 0.58% across various concentration levels, demonstrating its accuracy and reliability. The unique attributes of TS, including its cost-effectiveness, simplicity, high selectivity, and ultra-sensitivity, make it an excellent candidate for the detection of trace levels of Hg²⁺ in diverse applications.

We present the synthesis, characterisation, and application of a novel R2-based fluorescent probe for selective metal ion detection. Comprehensive studies using UV-Vis absorption and photoluminescence spectroscopy revealed strong binding with cobalt (Co²⁺) and aluminium (Al³⁺) ions, with a 2:1 binding stoichiometry (probe: metal) and with a detection limit as low as 5.5 × 10^-8 mol/L for aluminium and 3.2 × 10^-8 mol/L for cobalt, highlighting its remarkable sensitivity. With no interference from other metal ions, the probe showed outstanding stability and selectivity over a broad pH range. Analyses of actual water samples verified its usefulness in environmental monitoring. To further demonstrate the probe's potential in sophisticated sensing applications, it was also used to build a molecular logic gate. The experimental results were theoretically supported by Density Functional Theory (DFT) calculations, which also shed light on the binding mechanism. The R2 probe is emphasised in this work as a sensitive, specific, and adaptable instrument for environmental analysis and metal ion detection.

This article emphasizes the influence of pyridine ring substitutions in 2,2':6',2″-terpyridine unit, allowing for precise adjustment of ligand properties. This study explores terpyridine-based molecular systems, with its unique coordination properties assessed against a range of competing metal ions, highlighting the specific affinity of the terpyridine ligand towards aluminium (Al) and cobalt (Co) detection in Acetonitrile-water (ACN-H₂O) mixed solvent (80:20). The terpyridine-based probe's structural component is meticulously designed and detailed investigated to understand their influence on sensing performance. Synthesised probes are characterised using NMR, IR, UV-Vis spectroscopy, and mass spectrometry. Such modifications present ample opportunities to customise the attributes and applications of resultant metal complexes. The interaction between the terpyridine-based probes and target metal ions is investigated through various experimental methods, including fluorescence spectroscopy and UV studies along with unassisted discernment of Cobalt through Naked-Eye. Observation turns out that the limit of detection is 4.4 × 10^-8 mol/L for cobalt and 4 × 10^-7 mol/L for aluminium and coordination features Showing the binding stoichiometry to be 1:1 for R1. ADME Studies have been performed to analyse pharmacokinetic and biological actions. DFT calculations were performed to investigate the molecular probe's coordination features and its corresponding metal complex.

In order to quickly and conveniently detect multiple heavy metal ions in aqueous phase simultaneously, a polyethylene glycol passivated N-doping carbon quantum (p-N-CQDs) was synthesized by a hydrothermal method with citric acid (carbon source), urea (nitrogen source) and polyethylene glycol (passivator). The as-prepared p-N-CQDs could be evenly dispersed in deionized water, and the average diameter was 1.83 nm, resulting in 18.72% of fluorescence quantum yield. As a sensor, the fluorescence of p-N-CQDs would be significantly quenched with Fe³⁺ or Cu²⁺ under the different maximum emission wavelength of 452 nm and 448 nm, respectively. Therefore, a method for simultaneously detecting multiple heavy metal ions was proposed by discriminative fitting of the fluorescence emission peaks after metal ion quenching. Upon the experiments, two linear calibration curves between resolving fluorescence intensities of p-N-CQDs and concentration of the metal ions were obtained within a range of 10 to 1000 µM of Cu²⁺ and 40 to 800 µM of Fe³⁺. And a limit of detection (LOD) of 0.032 µM was attained after resolving the curves based on the emission wavelength of 448 nm for Cu²⁺ and 452 nm for Fe³⁺ by a peak splitting software. In addition, the stability, selectivity and anti-interference of the proposal senor was confirmed.

Herein, an imidazo-pyridin-derived fluorescent probe ImPy-HS was developed for monitoring the hydrogen sulfide (H₂S) level in the water decoction of Chinese medicinal materials. Under the excitation at 355 nm, ImPy-HS exhibited the obvious fluorescence response at 490 nm. The detection system with ImPy-HS showed the advantages including relatively high sensitivity, high selectivity, and high steadiness. Especially, in the water decoction of Chinese medicinal materials with H₂S from both addition and excessive fumigation then reduction, ImPy-HS achieved the monitoring of the H₂S level. ImPy-HS also realized the imaging of both exogenous and endogenous H₂S as well as the water decoction-treated affection. The information here was meaningful for studying the quality control of Chinese medicinal materials.

The search for fluorophores with intense absorption and emission in the red region of the spectrum is an important task, as such compounds can be used in fluorescence imaging, providing high image resolution due to the deep penetration of low energy photons into tissues. In this paper, we present the results of the synthesis and photophysical characterization of a novel ms-benzimidazole-4,4',5,5'-tetramethyldipyrromethene bis(difluoroborate) (BOIMPY) compound, which exhibits intensive absorption and emission in the long-wavelength region while maintaining high fluorescence quantum yields (up to 60%). Using DFT analysis, we investigated the geometry of BOIMPY in both ground and excited states and described the influence of the molecular structure on its practically relevant photophysical properties.

A dual-responsive probe 8-N, N-diethylamino-3-(1H-benzoimidazol-2-yl)-2H-pyrano[2,3-b]quinoline-2-imino (PQI), pyrano[2,3-b]quinoline as fluorophore, two nitrogen atoms as receptor sites, was developed for the colorimetric and fluorescence detection of Hg²⁺ and COCl₂ in different solvents. PQI showed good recognition ability for Hg²⁺ via the absorbance decrease, fluorescence quenching by the formation of PQI-Hg²⁺ complex in MeOH/H₂O (4/1, V/V). In addition, PQI could specifically react with COCl₂ via intramolecular cyclization to form a cyclic urea product, which exhibited absorption and fluorescence emission changes, and then realized the detection of COCl₂. Moreover, the optical responses of PQI to Hg²⁺ and COCl₂ featured high selectivity, fast response (within 30 s), and low detection limit (73 nM for Hg²⁺ and 25 nM for COCl₂, respectively). Furthermore, PQI could detect Hg²⁺ in real water samples with good recoveries and small relative standard deviations, and could be prepared as a PQI-loaded test strip to monitor gaseous COCl₂ in an in-site, real-time, highly sensitive manner, demonstrating the practicability of PQI in Hg²⁺ and gaseous COCl₂ detection.

As a typical non-ferrous metal, copper is heavily used in the manufacturing and chemical industries. Copper pollution has been demonstrated to have a significant detrimental impact on the natural environment, as well as causing irreparable damage to the human body, such as elevated Cu²⁺ levels have been identified as a factor in the pathogenesis of AD (Alzheimer's disease). In this study, novel nanoscale carbon dots Blue-CDs (B-CDs) were obtained by the solvothermal approach in formamide solution utilizing citric acid as the carbon source and ethylenediamine as the nitrogen dopant. The particle size of B-CD was assessed to be 2.17 nm, with a quantum yield (QY) of 10.28%. The B-CDs were found to be extinguished upon exposure to Cu²⁺, which exhibited a good fluorescence detection linear relationship within the concentration range of 0.25-10.0 µM Cu²⁺, showing a limit of detection (LOD) is 0.18 µM. B-CDs have been effectively used for the measurement of Cu²⁺ in actual aqueous systems. It is due to the chemical reactions that take place among the B-CDs and the Cu²⁺ that make the sensor highly sensitivities and highly selectivities. The results of the experiment demonstrate that the fluorescence quenching process is a consequence of Cu²⁺ binding to the amino groups of carbon dots, forming complexes via a non-radiative photoinduced electron transfer process. In conclusion, the described simple sensing techniques could be effectively utilized as monitoring tools for Cu²⁺ in environmental waters.