Journal of Fluorescence最新文献

Strontium orthogermanate (Sr₂GeO₄) doped with Mn⁴⁺ and Cu²⁺ phosphors were prepared by high temperature solid state reaction. All the prepared phosphors were crystallized in the orthorhombic lattice with space group Pbn2₁. The surface morphology of prepared phosphors contains irregular shaped objects with considerable agglomeration. The FT-IR and Raman profiles of the compositions gave characteristic bands belonging to GeO₄^4- tetrahedra. Photoluminescence profiles of Sr₂GeO₄: Mn⁴⁺ compounds are characterized by red emission at 647 nm upon excitation at 433 nm, while Sr₂GeO₄: Cu²⁺ compositions gave orange emission at 603 nm under excitation at 403 nm. The emission mechanism of Sr₂GeO₄: Mn⁴⁺ was explained by Tanabe-Sugano energy level diagram of Mn⁴⁺ ion. The CIE chromaticity coordinates, color purity (CP) and correlated color temperature (CCT) values were deduced. Thermoluminescence profiles are characterized and trap depth parameters were evaluated. These compositions may be useful in the manufacturing of cool and warm solid state lighting sources.

In this study, a novel fluorescent "turn-on" probe, (E)-N'-(2-(2-hydroxynaphthalen-1-yl) ethylidene)-2,5-diphenyl-2 H-1,2,3-triazole-4-carbohydrazide (G₄), was designed and synthesized, and fully characterized by various analytical techniques. Spectroscopic investigations revealed that G₄ exhibits excellent selectivity and sensitivity toward Al³⁺, with a 1:1 binding stoichiometry and a detection limit of 1.623 nM. Its advantages over existing probes include the lower detection limit and a distinct color reaction under UV light, which facilitates straightforward qualitative detection with lower cytotoxicity. The sensing mechanism was elucidated through density functional theory (DFT) and quantum chemical calculations. Then the practical utility of G₄ was demonstrated through recovery experiments in real water samples and its development into a portable test kit. Furthermore, cell experiments and zebrafish imaging confirmed its biocompatibility and applicability in biological systems with lower cytotoxicity. As a candidate drug that may be developed and utilized, the interactions of G₄ with two serum proteins (HSA and HIgG) were also investigated through spectrofluorometric and molecular docking analysis, revealing hydrogen bond or van der Waals forces as the main mode of action, suggesting potential for further biomedical applications. These results highlight G₄ as a highly sensitive, selective, and dual-functional fluorescent probe with significant potential for environmental monitoring and biological sensing.

The existence of microplastics in the environment is currently a significant worldwide concern. Microbeads found in personal care and cosmetic products (PCCPs) are one of the primary sources of microplastics, which pose a threat to human health and the environment. This study was designed to detect microplastics in a popular PCCP (facial scrub and face wash). Twenty products (10 facial scrubs and 10 face washes) were analyzed using Rhodamine B staining prepared in ethanol, distilled water, and acetone, followed by fluorescence microscopy. All samples tested positive for the presence of microplastics. The observed microplastics displayed orange, red, and green fluorescence and varied in shape, with most appearing irregular and fragmented. One- way ANOVA (F = 31.87, p = 0.0001) demonstrated that there was statistical difference between these solvents and ethanol (11.40 ± 5.03) provided the most effective staining results. FTIR analysis further confirmed that polystyrene and polyurethane as the most common polymers in facial scrubs, while ethylene-propylene copolymer and polystyrene were predominant in face washes. Additional polymers, including polyvinyl chloride, polypropylene, and polyethylene terephthalate, were also detected in some samples. This research highlights the occurrence of microplastics in facial scrubs and face washes and emphasizes the need for increased awareness and stronger regulatory measures to limit their use in cosmetic formulations.

The detection of ferric ions (Fe³⁺) is of crucial importance in environmental monitoring and biomedical diagnostics. However, developing highly selective, sensitive, and environmentally friendly detection methods remains an important challenge. In this study, nitrogen-doped carbon quantum dots (N-CQDs) were green-synthesized as a novel and sustainable fluorescent sensor for Fe³⁺ detection. The synthesis was achieved via a one-pot hydrothermal method using licorice powder as a renewable carbon source and p-phenylenediamine as a nitrogen dopant. The synthesized N-CQDs display bright blue fluorescence, with a maximum emission at 436 nm when excited at 320 nm. They serve as a highly selective and sensitive fluorescent probe for Fe³⁺, showing a distinct fluorescence "turn-OFF" response. The sensor offers a linear range of 0 to 50 µM for Fe³⁺ detection, with a calculated limit of detection (LOD) of 0.346 µM. A notable aspect of this work is the demonstration of an "ON-OFF-ON" sensing paradigm. The fluorescence quenched by Fe³⁺ can be effectively restored ("turn-ON") by adding ascorbic acid, which reduces Fe³⁺. This "ON-OFF-ON" behavior emphasizes the specificity of N-CQDs towards Fe³⁺ to Fe²⁺. The practical applicability of the sensor was confirmed through successful detection of Fe³⁺ in complex real-world samples, including beer and human blood serum, achieving excellent recovery percentages (97.6% - 101.7%) and low relative standard deviations (RSD, 0.9% - 1.8%). Overall, this research presents an environmentally friendly N-CQD-based fluorescent sensor with a unique reversible fluorescence response "ON-OFF-ON" for Fe³⁺, holding great potential applications in environmental monitoring and biomedical diagnostics.

The present work deals with the preparation and characterization of novel g-C₃N₄/Fe₂WO₆ (GCNFW) nanocomposite for the effective detection and removal of Fe(III). where thermal polymerization (g-C₃N₄), ball milling - solid state reaction (Fe₂WO₆) and ultrasonication (GCNFW nanocomposite) methods were adopted for the preparation. The structural and morphological studies of GCNFW nanocomposite ensure the presence of single-phase orthorhombic Fe₂WO₆ decorated g-C₃N₄ and the same was free from impurities. The selectivity of GCNFW was tested by considering 15 metal ions namely Hg(II), Ni(II), Cd(II), Co(II), Sn(IV), Al(III), Cr(III), Pb(II), Zn(II), In(III), Fe(III), Cu(II), As(III), Sr(II) and Ba(II). Interestingly the prepared GCNFW nanocomposite could behave as fluorescent sensor and electrochemical sensor. As a fluorescent sensor, GCNFW has remarkable "Turn-off" fluorescence selectivity towards Fe(III) with LOD of 26.6 nM. The Differential Pulse Voltammetry (DPV) studies confirmed the electrochemical sensing behaviour of GCNFW towards Fe(III) with LOD of 1.23 µM. The prepared GCNFW has achieved 303.30 mg/g adsorption capacity and 87.48% removal efficiency within 15 min. A prototype water purifier made of GCNFW with Polyurethane foam (GCNFW-PU) could have the maximum adsorption capacity of 0.098 mg/g and removal efficiency of 99.36% towards Fe(III) in the real time drinking water samples collected from 7 different localities at Madurai District, Tamil Nadu. Hence the prepared GCNFW nanocomposite may serve as a promising fluorescent as well as electrochemical sensor material for the effective detection and removal of Fe(III) in the realm of heavy metals polluted drinking water remediation applications.