Journal of Fluorescence最新文献

The proposed study introduces a rapid, sensitive, and simple synchronous spectrofluorimetric technique for simultaneous quantification of relebactam, cilastatin, and imipenem in marketed pharmaceutical forms and biological fluids. Using synchronous fluorescence spectroscopy at Δ λ = 110 nm, cilastatin was detected at 360 nm. Fourier Self-Deconvolution was subsequently applied to the spectrum to estimate relebactam and imipenem at 430 nm and 470 nm, respectively after detection of cilastatin at 360 nm ensuring no cross-interference. The pH was adjusted to 8.0 using 2.0 mL of alkaline borate buffer. This approach allowed for the precise quantification of relebactam, cilastatin, and imipenem through ranges of 50-400 ng mL^- 1, 20-500 ng mL^- 1, and 50-500 ng mL^- 1 respectively. The lower detection and quantitation limits were 9.9 and 29.7 ng mL^- 1 for REL, 4.5 and 13.6 ng mL^- 1 for CIL and 5.5 and 16.5 ng mL^- 1 for IMP. The proposed method was successfully applied for the determination of studied drugs in their pharmaceutical formulations with a high degree of accuracy and without interference from common excipients. This approach allowed for the precise quantification of relebactam, cilastatin, and imipenem through ranges of 50-400 ng mL^- 1, 20-500 ng mL^- 1, and 50-500 ng mL^- 1, respectively. The proposed method was rigorously validated according to ICH guidelines. Furthermore, the method's environmental impact was assessed using Eco-scale and Green Analytical Procedure Index (GAPI) techniques.

Pyridine, N-containing heterocyclic organic compound, displays strong coordination capabilities with various metal ions. It can be synthesized through various methods, such as Friedlander synthesis, heterocumulene synthesis, cross-coupling reactions, the Radziszewski reaction, Bonnemann cyclization, as well as cobalt-catalyzed synthesis. Experimental and spectroscopic analyses have demonstrated a strong binding affinity between pyridine and several heavy metal ions, including Pb²⁺, Hg²⁺, and Cd²⁺ ions. The escalating environmental pollution caused by the disposal of heavy metal ions in rivers, open air, and water reservoirs poses a significant threat to both ecosystem and human health. To address these environmental challenges, a cost-effective and easily synthesized chemosensor has been prepared for identifying toxic heavy metal ions in various samples. Pyridine's photophysical properties make it an effective sensor for detecting Hg²⁺ ions, displaying fluorescence quenching or enhancement in their presence. The coordination between pyridine and Hg²⁺ ions lead to shifts in the absorption spectra. The pyridine-based sensor has been evaluated for its sensitivity, selectivity, and detection limits under different experimental conditions. Pyridine's solubility and environmental stability make it applicable for real-time detection, making pyridine probes valuable tool for monitoring toxic Hg²⁺ ions in the environment. The results demonstrate that the pyridine-based chemosensor exhibits good selectivity and sensitivity for targeting Hg²⁺ ions, with detection limits within acceptable ranges. This review (from years 2011 to 2023) emphasizes the preparation of various substituted pyridine compounds as selective, sensitive, and specific sensors for real-time detection of Hg²⁺ ions.

Zinc selenide is an excellent matrix material to dope with rare-earth and transition metal to achieve mid-infrared luminescence to develop high power lasers. The luminescence, morphology and refractive index is significantly affected by the doping and defects generated due to size and valency of dopants, concentration, growth process and convection during the growth. The aim of the study is to investigate effect of point and line defects generated due to low doping of iron and chromium on the emission and morphology of the zinc selenide. Luminescence and morphological properties of large iron and chromium doped zinc selenide single crystals were studied to evaluate the effect of extremely low residual impurities and defects associated with the doping process. The emission properties following both short wavelength (i.e., ultraviolet; 350-370 nm) excitation and longer wavelength (i.e., near infrared; 850-870 nm) excitation were characterized. Luminescence emission bands were identified in both doped crystals. In addition to the primary emission bands, satellite peaks and intra-center transitions were also observed. Due to local population defects associated with the residual impurities (ppm to ppb) in the Fe-ZnSe and Cr-ZnSe crystals, peak emission wavelengths were observed to shift. The emission bands were found to decrease in intensity due to recombination of residual impurity co-dopants and complex defects generated during growth and fabrication. Cryogenic temperature analyses revealed a very clean emission band due to freezing of some of the point and line defects. An emission band observed at 980 nm for both crystals at room temperature as well as cryogenic temperatures indicates a vibronic peak in ZnSe. The scanning electron microscopy (SEM) images of the local morphology support the conclusion that small crystallites in doped crystals are also present.

Fluoroquinolones (FQs) are widely used in hospitals, animal husbandry and aquaculture for the treatment of infectious diseases. However, overuse of FQs poses a potential threat to the environment and human. Detection of antibiotics is of great importance in various fields. In this paper, bright yellow fluorescence carbon dots (y-CDs) with quantum yield of 32% were synthesized via a simple and rapid microwave-assisted method using o-phenylenediamine and salicylic acid as raw materials. The fluorescence properties of y-CDs varied under different excitation wavelengths. It is discovered that the excitation wavelength is a critical factor to develop a dual functional fluorescence probe. Under selected excitation wavelength (355 nm), y-CDs can realize dual detection of norfloxacin (NOR) and gatifloxacin (GAT) with good selectivity and high sensitivity in a "turn-on" mode. The detection limits of NOR and GAT are 0.0881 µM and 0.0125 µM, respectively. y-CDs prove practical application in the detection of NOR and GAT in milk and egg samples.

In recent year, the uses of carbon quantum dots (CQDs) have increased in many fields. Herein we report, synthesis of fluorescent nitrogen doped carbon quantum dots (N-CQDs) by simple and ecofriendly hydrothermal method. The as-synthesized N-CQDs were characterized by various techniques and the quantum yield was also calculated. Then, application of N-CQDs were performed as a sensor for detection of ferric ions (Fe³⁺) based on static quenching mechanism (turn-off) which occurred due to formation of non-fluorescent complex between N-CQDs and Fe³⁺ ions. Interestingly, fluorescence intensity of quenched N-CQDs has been significantly recovered (turn-on) by addition of ascorbic acid (AA). The recovery mechanism is based on the redox reaction between Fe³⁺ ions and AA. Thus, N-CQDs has been used as fluorescence "turn-off-on" sensor for detection of Fe³⁺ ions and AA. Further this detection system is used for detecting Fe³⁺ ions in Moringa oleifera and AA in citrus lemon.

Calcium sulfide (CaS) is a widely investigated alkaline earth sulfide nanophosphor with promising applications in optoelectronics and biomedical fields due to its excellent photoluminescence properties. The selection of the synthesis method is a crucial factor in determining the efficacy of nanophosphors for various applications. This review provides a comprehensive overview of the various synthesis techniques employed to develop CaS nanophosphors, including solvothermal, alkoxide, sol-gel, microwave, wet chemical co-precipitation, solid-state diffusion, and single-source precursor methods. The structural and optical properties of CaS nanophosphors are discussed in detail, highlighting the influence of different dopants on the emission color, which can be tuned from blue to red. The review also explores the potential applications of CaS nanophosphors in optoelectronics and biomedicine. This review serves as a valuable resource for researchers interested in developing CaS nanophosphors for various optoelectronic and biomedical applications, providing insights into the latest advancements and future prospects in this field.

A fluorescence probe (Probe-ITR) was designed and synthesized for the rapid detection of Zn²⁺ based on the excited state intramolecular proton transfer (ESIPT) mechanism. The specific recognition ability of Probe-ITR to Zn²⁺ was tested using UV-VIS and fluorescence emission spectroscopy. The results demonstrated a rapid response within 40s upon addition of an appropriate amount of Zn²⁺ into the mixed solution of the target probe molecules (DMSO/PBS = 5/5). Under 365 nm ultraviolet light irradiation, the colorless solution changed to yellow-green fluorescence with a 150-folds increase in intensity. Furthermore, the detection limit for specific recognition of Zn²⁺ by the probe molecule is only 17.3 nmol/L, indicating high sensitivity. The practical application potential of the probe molecules was enhanced by employing on information storage and conducting cell imaging experiments.

Spectral down-shifting materials can convert the less utilized photons in the solar spectrum into the portion that solar cells can fully utilize, providing an effective means of improving the efficiency of solar cells. In this work, the spectral down-shifting material Ba₅Si₂O₆Cl₆: Eu²⁺ (BSOC) was prepared by a high-temperature solid-state method. The fluorescence spectra indicate that the absorption spectrum of BSOC can cover the range of 210-500 nm, and has a strong emission spectrum with a broadband of 410-650 nm. The wider spectral characteristics make it convenient to utilize the solar spectrum efficiently. Additionally, the BSOC phosphors precisely compensate for the weak absorption of YAG: Ce³⁺ (YAG) phosphors below 425 nm. The YAG and BSOC phosphors were mixed, and the hybrid material has a wider absorption range (200-540 nm) compared to YAG or BSOC alone. Finally, the electrical properties of the packaged cells were tested, and the results showed that the packaged cells with hybrid materials had higher short-circuit current density and photoelectric conversion efficiency compared to YAG or BSOC alone. In addition, the efficiency of the packaged cells with hybrid materials increased from 19.54 to 20.08% compared with the bare cells, a relative increase of 2.760%.

The intricate interplay between the irradiation wavelength, the fluorophore quantum yield (QY) and penetration depth profoundly influences the efficacy of in vivo fluorescence imaging in various applications. Understanding the complex behavior of fluorescence in vivo, specifically how variations in wavelength affect the QY of commonly used dyes and the depth of imaging is crucial for optimizing fluorescence imaging techniques, as it directly impacts the accuracy and efficiency of imaging in biological tissues. In our study, we explore these dynamics through Monte Carlo simulations conducted under conditions reflective of wide-field fluorescence imaging, examining how variations in wavelength impact the dye's QY and depth of imaging, and consequently, the fluorescence behavior. A transition in the exponential decay of the emission depth exponent is observed around the 500-600 nm range, indicating varying degrees of influence of depth on the fluorescence emission. The analysis of the fluorophore's QY reveals wavelength-dependent variations, with the most significant impact observed in the 600-700 nm range. Moreover, we continued our investigation to explore multiplexing, unveiling insights into the spacing between identical spots in multiplexing images across various depths and wavelengths.

The current study reports a novel fluorescent chemosensor based on the tagging agent 4,5,6,7-tetrachloro-2',4',5',7'-tetraiodofluorescein (Rose Bengal, RB) for detection of trace levels of Hg²⁺in environmental water. The established probe has been based upon liquid-liquid extraction (LLE) of the developed ternary complex ion associate {[Hg (bpy)₂]²⁺.[RB]^2-} of Hg²⁺ -2,2- bipyridyl complex [Hg (bpy)₂]²⁺ and RB at pH 9.0 onto chloroform and measuring the resulting fluorescence enhancement signal intensity at λ_ex/em = 570/ (580-600) nm. The limits of detection (LOD) and quantification (LOQ) of for Hg²⁺ was calculated to be 6.06 and 20 nM with a linear dynamic range (LDR) of 0.02-20µM, respectively. The stability constant, stoichiometry, chemical equilibria, and the thermodynamic parameters (ΔH, ΔS, and ΔG) of the developed ion associate were evaluated and assigned. Student's t and F tests at 95% confidence were fruitfully used for validation of the proposed methodology for Hg²⁺ detection in water samples with the aid of inductively coupled plasma-optical emission spectrometry (ICP-OES). The established strategy was successfully applied for detection of trace levels of Hg²⁺ in water samples with acceptable results. The proposed probe was satisfactorily applied for total determination and speciation of Hg in various water samples. Integrating the functional chelating agent onto associate formation to improve the selectivity and sensing properties of the LLE combining sensing probe towards target analyte in water represent the main interest.