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Fabrication & Characterization of Simple Structure Self-Assembled Graphene Oxide Based Heavy Metal Ion Sensor
摘要： The simple structure and high robustness of heavy metal sensors were developed by implementing a GO/Au/FR4 Substrate configuration. In this study, the sensing characteristics of an in-house fabricated heavy-metal-ion sensor (HMS) with graphene oxide (GO) as the sensing element was presented. The HMS employed a three electrodes configuration architecture, while GO of various concentrations ranging from 0.1 to 1 mg/ml would serve as the sensing medium. The surface of the working electrode was decorated with GO through drop-casting technique. Several types of heavy metal ions such as lead (Pb), mercury (Hg), and cadmium (Cd) were used in this study. The concentration of each was prepared according to the maximum exposure limit imposed by the World Health Organization, with Pb (10 ppm), Hg (1 ppm), and Cd (5 ppm). The sensing performance was found to be proportionate to GO concentration when the sensor was exposed to 10 ppm of Pb. On selectivity test using 1 mg/ml of GO, the sensor exhibited superior sensitivity towards 10 ppm of Pb, ～ 1666.6%; followed by 5 ppm of Cd, ～ 512.8%, while 1 ppm of Hg being the least detected, ～ 10.5%. This signified GO shows greater affinity towards Pb ions detection in comparison to others.
关键词： graphene oxide,sensors and working electrode,Electrochemical,IDE,heavy metal ions
更新于2025-09-12 10:27:22
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A green luminescence of lemon derived carbon quantum dots and their applications for sensing of V5+ ions
摘要： A simple approach for the synthesis of luminescent carbon dots (C-dots) has been developed by the hydrothermal treatment of lemon juice as carbon precursor at 240 °C in 12 h. The obtained C-dots were found to emit bright green luminescence. Meanwhile, the C-dots exhibited excitation-dependence, photo-stability, and well dispersibility. The C-dots were used for detection of ion V5+ in water and serum, which was based on V5+ induced luminescence quenching of C-dots. The selectivity experiments revealed that the luminescent sensor was specific for V5+ ions even with interference by high concentrations of other metal ions. Detection limits for V5+ ions was 3.2 ppm. These results suggest that the present C-dots are potential application in optoelectronic, imaging and luminescent probing of V5+ ions.
关键词： Quantum dots,Nanoparticles,Luminescence,Metal ions,Carbon materials
更新于2025-09-11 14:15:04
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Comprehensive Supramolecular Chemistry II || Fluorescent Sensors for Biological Metal Ions
摘要： All living organisms require metals. They have vital roles as catalysts, osmotic regulators, signaling molecules, and transport molecules. Many different metals are present in the human body, and carry out a range of essential functions: for example, oxygen travels in the blood bound to iron in hemoglobin, neurons communicate by changing their sodium and potassium levels, and metal catalysts like manganese in superoxide dismutase speed up biochemical reactions.1 Although metals are so essential, they make up less than 3% of the human body by weight. The most abundant metals found in the body belong to periodic groups I and II, including calcium (1.5%), potassium (0.4%), sodium (0.2%), and magnesium (0.1%). Essential transition metals are considered to be trace elements because they collectively make up less than 0.1% of body mass. These include zinc, chromium, vanadium, cobalt, copper, manganese, molybdenum, and tin.2,3
关键词： Fluorescent Sensors,Biological Metal Ions,Fluorescence Imaging,Metal Probes,Ratiometric Probes
更新于2025-09-10 09:29:36
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A Bifunctional Luminescent Coordination Polymer as Recyclable Sensor for Detecting TNP and Fe3+ with High Selectivity and Sensitivity
摘要： A thermo-stable three dimensional network [Cd2(BPDPE)2(1,2-H2bdc)2]n (1) (1,2-H2bdc = 1,2-benzenedicarboxylic acid, BPDPE = 4,4′-bis(pyridyl)diphenyl ether) with blue fluorescence was successfully synthesized and characterized. Complex 1 is a two-dimensional layer constructed by BPDPE connecting [Cd(1,2-bdc)]n one-dimensional chains, then a three-dimensional network is finally formed via π···π interactions. Importantly, Complex 1 presents an excellent fluorescent MOF sensor for highly sensitive and selective detecting TNP, the Ksv is up to 1.03×105 M-1. Further more, complex 1 can be quickly regenerated by simple washing, exhibiting good recyclability for detecting TNP. In addition, complex 1 shows higher sensitive fluorescent sensor for detecting Fe3+ cation than other metal ions. the Ksv is calculated to be 1.84×105 M-1. Furthermore, the quenching mechanisms of complex 1 as bifunctional sensor were studied as well.
关键词： Nitro aromatic explosives,Selectivity and sensitivity,Fluorescence sensing,Metal ions,Coordination polymer
更新于2025-09-10 09:29:36
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An Ultrastable Magnesium–Organic Framework as Multi-responsive Luminescent Sensor for Detecting Trinitrotoluene and Metal ions with High Selectivity and Sensitivity
摘要： A pH and thermal stable three dimensional framework [Mg(ATDC)(H2O)2]n (1) (H2ATDC = 2'-amino-1,1':4',1''-terphenyl-4,4''-dicarboxylate) with blue fluorescence has been successfully synthesized and characterized. The Mg-MOF contains 2D [Mg(COO)2]n sheet, which links ATDC2- to generate 3D framework with accessible -NH2 groups, which could be beneficial to impact the reorganization on specific small molecules. Importantly, it is the first reported highly selective fluorescence Mg-MOF for sensing 2,4,6-Trinitrotoluene (TNT), and have the highest sensitivity for detecting Chromium(III) simultaneously through fluorescence quenching. Furthermore, the quenching mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of Mg-MOF and analytes, rather than the interactions between –NH2 and analytes.
关键词： Metal organic frameworks,Metal ions,Fluorescence sensing,2,4,6-Trinitrotoluene
更新于2025-09-09 09:28:46
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Theoretical explanation of strong enhancement of alkali metal ion neutralization on Au nanoclusters
摘要： We present a theoretical study of alkali metal ion neutralization on gold nanoclusters. The experimental time-of-flight measurements show that neutral fraction of alkali metal ions scattered from flat Au surface is low (3%-15%), but it increases up to 50% for small Au clusters. Several possible explanations of alkali metal ions neutralization enhancement on nanoclusters have been proposed earlier, but they do not fully explain existing experimental data. We introduce alternative explanation of neutralization probability enhancement for small clusters. It is based on ion energy level shift due to interaction with image/induced charges, which significantly differs in the case of metallic nanocluster and in the case of flat continuous metallic surface. Another known mechanism is greater neutralization rate on positively charged edge atoms of Au nanocluster. The combination of two mechanisms and difference in atomic radii possibly explains greater neutralization probability enhancement for Na+ in comparison to Li+.
关键词： Resonant Charge Transfer,Low Energy Ion Scattering (LEIS),Alkali Metal Ions,Neutralization Effect
更新于2025-09-09 09:28:46
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Synthesis of Novel Organic-Inorganic Hybrid Fluorescent Microspheres and Their Applications as Fe(III), Hg(II) and Biothiols Probes
摘要： Organic-inorganic hybrid fluorescent microspheres (OI-FMs) without typical fluorophores were prepared. Fluorescence quantum yield of OI-FMs is up to 0.7 after being heated in an oven at 120°C (named as OIFMs-120). Interestingly, OI-FMs-120 shows different detection performances in different solvents. It can be used for qualitative and quantitative detection of Fe3+ with a detection limit of 37.8 nM in absolute ethanol. While in aqueous solution, it can be applied as an ONOFF-ON fluorescent probe. Fluorescence of the probe is quenched by Hg2+and later recovered by biothiols. The detection limit are as low as 34.9 nM for Hg2+, 91.0 nM for Cys, 0.12 μM for Hcy and 0.13 μM for GSH in aqueous medium, respectively.
关键词： Biothiols,Heavy metal ions,Atypical fluorophores,Fluorescence sensor
更新于2025-09-09 09:28:46
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Microwave Induced Center-Doping of Transition Metals Ions in Aqueous CdS NCs with Special Optical Properties
摘要： Under microwave irradiation, we systematically studied the formation of transition metal ions (TM), Ag+, Mn2+, Cu2+, Fe2+, Co2+ and Ni2+, doped CdS semiconductor nanocrystals in a pure water solution. The center-doping strategy is essential for achieving efficient internal-doping to improve the optical properties and stability of doped nanocrystals. The resulting TM doped nanocrystals have a high photoluminescence quantum yield (~ 60%) and an amazingly large range of the visible spectrum (480 ~ 650 nm). For Mn2+ doped CdS nanocrystals, significant high photoluminescence quantum yield, between 20% and 50% even at more than 600 nm, was achieved and there is potential for them to be directly used as a consummate toner for multicolor sensing and encoding without ligand exchange. Highly emissive-doped nanocrystals synthesized under designed conditions have been found to have excellent stability; samples could be stored for months without precipitation. In practice, this approach has great potential to promote the metal doping of various semiconductor nanocrystals to realize the specific advantages of doped nanocrystals in water solution.
关键词： transition metal ions,microwave,nanocrystals,doping,CdS
更新于2025-09-09 09:28:46
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Synthesis and characterization of luminescent metal–organic frameworks for the selective recognition of Cu2+ cation and Tryptophan
摘要： Three metal-organic frameworks (MOFs), namely, [Mn(CPP)2(H2O)]n (I), [Cd(CPP)2(H2O)]n (II) and {[Zn2(CPP)2(CO3)]·(ClO4)·(H2O)2}n (III) (HCPP = 4'-(4-(4-carboxylphenoxy)-2,2':60,20-terpyridine), were successfully achieved under hydrothermal conditions. The as-synthesized coordination polymers have been characterized by IR spectroscopy, elemental analyses and single crystal X-ray diffraction. Single-crystal X-ray diffraction analyses indicate that compounds ⅠⅠ and ⅡⅡ display isomorphous and isostructural, in which the central metal ions present distorted octahedral configurations. ⅠⅠ and ⅡⅡ feature fascinating 3D frameworks based on p/p and CeH/p interactions between the pyridine rings ligands, while compound ⅢⅢ possesses a 3D net interlinked via C-H/p interactions appertaining CPP ligands. In their 3D frameworks, the {MnN3O3}, {CdN3O3} and {ZnO2N3}e{ZnO2N3} building units are observed, respectively. Luminescent properties of coordination polymer ⅡⅡ and ⅢⅢ demonstrate that they may be acted as fluorescent sensors toward Cu2+ cation and Tryptophan, respectively. Furthermore, investigations on magnetic property reveal that coordination polymer ⅠⅠ presents antiferromagnetic coupling.
关键词： Magnetic analysis,Luminescent recognition,Transition metal ions,Hydrothermal synthesis,Metal organic frameworks
更新于2025-09-04 15:30:14