Detection Of Fe3 Research Articles

Study on the fluorescent covalent organic framework for selective “turn-off”recognition and detection of Fe3+ ions

Covalent organic framework (TT-COF) based on 2,5-dihydroxyterephthalaldehyde and 1,3,5-tris(4-aminophenyl)benzene was prepared. TT-COF displays obvious fluorescence quenching response in ethanol towards Fe3+ with high selectivity accompanied by fluorescence red-shift. The fluorescence intensity of TT-COF at 425 nm shows a linear relationship with Fe3+ concentration with a low detection limit of 8.4 × 10−5 mol/L. The high fluorescence selectivity can be attributed to the synergetic effects of unique pore structure and the coordination of Fe3+ ions with N and O atoms of TT-COF. The coordination between TT-COF and Fe3+ ion was confirmed by reversible fluorescence change upon the addition of ethylenediaminetetraacetic acid disodium salt (EDTA), XPS spectra, and DFT calculation. The fluorescence quenching is attributed to the intramolecular charge transfer (ICT) and the absorption competition quenching (ACQ) mechanism. This work indicating the fluorescent COF as a fluorescence sensor has promising application in recognition and detection of specific metal ions.

Highly sensitive and selective fluorescence sensing and imaging of Fe3+ based on a novel nitrogen-doped graphene quantum dots.

A novel nitrogen-doped graphene quantum dots (N-GQDs) with a green fluorescence emission was synthesized through microwave method using citric acid and semicarbazide hydrochloride as reactants. The as-synthesized N-GQDs exhibited good stability, excellent water solubility, and negligible cytotoxicity. Due to intermolecular charge transfer, ferric ion (Fe3+ ) has a strong quenching effect on the N-GQDs. Fluorescence quenching has a linear relationship with the Fe3+ concentration in the range 0.02-12 μM. The detection limit was 1.43 nM. What is more, it is worth mentioning that the obtained N-GQDs showed high selectivity and sensitivity towards Fe3+ . Under the optimum conditions, the addition of 10-fold copper ions and 100-fold other metal ions had no influence on the detection of Fe3+ (0.8 μM), which indicated a higher sensitivity compared with that of the reported methods. Due to their excellent properties, the obtained N-GQDs was successfully applied for sensing and imaging Fe3+ in water samples and HeLa cells.

When Fluorescent Sensing Meets Electrochemical Amplifying: A Powerful Platform for Gene Detection with High Sensitivity and Specificity.

Ultrasensitive and ultraselective detection of the gene requires emergency development to meet the medical demands and infectious disease control. Herein we report a versatile and scalable method based on electrochemical-chemical-cyclic amplification (EC-CA) and fluorescence detection for ultrasensitive gene sensing. The EC-CA is achieved by an electro-Fenton reaction (EFR). The hydroxyl radicals generated at EFR are trapped by terephthalic acid to form highly fluorescent 2-hydroxyterephthalic acid, which can be sensitively detected by a fluorescence spectrophotometer. The method is the first to be able to amplify the signal and reduce the noise simultaneously by using the conventional analytical methods directly. This described method can be used for reliable Fe3+ quantification in the range from 0.1 nM to 0.08 mM. The calculated limit of detection (LOD) is 0.02 nM. Then, hepatitis B virus (HBV) and p53 gene were detected by this proposed method through introducing the Fe3O4 nanoparticles into the gene hybridization system. The LODs for HBV and p53 gene even topped out at 2.6 pM and 1.7 fM, respectively. We demonstrated that the finally recorded signal was triply amplified through the EC cycle, Fe3O4 nanoparticles, and sensitive fluorescence detection. At the same time, the background signal arisen from matrix effects and readout noise was effectively suppressed. This method shows it is simple, convenient, and operational through the detection of Fe3+, HBV, and the p53 gene in blood samples, respectively. We believe our method will make a significant, near-term impact on the development of high-sensitivity methods that are versatile and scalable.

Synthesis, Crystal and Hirshfeld Surface Structure of a 1D Ni(II) Coordination Polymer: Luminescent Detection for Fe3+ in H2O

AbstractA one‐dimensional (1D) Ni(II) coordination polymer, {[Ni(oba)(1,3‐bix)(H2O)]⋅H2O}n (1), where H2oba=4,4′‐oxybis(benzoic acid) and 1,3‐bis(imidazol‐l‐yl‐methyl)benzene=1,3‐bix, was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis, single‐crystal X‐ray diffraction, and Hirshfeld surface analyses. X‐ray diffraction structural analysis has revealed that the oba and 1,3‐bix ligands connects the Ni(II) atoms to form a square‐wave 1D chain, which is further extended into 2D supramolecular layers through O−H⋅⋅⋅O hydrogen bonds and π⋅⋅⋅π stacking interactions. 1 shows intense luminescence in H2O and exhibits a selectivity and detection for Fe3+ ions through the fluorescence quenching effect at room temperature.

Iron(III) Sensors Based on the Fluorescence Quenching of Poly(phenylene ethynylene)s and Iron-Detecting PDMS Pads

The detection of Fe ions is critical to environmental monitoring and disease diagnosis. We herein report fluorescent conjugated polymers that exhibit fluorescence quenching upon the addition of Fe (III) ions with the total concentration of 2 ppm. The polymer backbone consists of poly(phenylene ethynylene) (PPE) with side-chains bearing triethylene glycols or alkyl groups. The quenching phenomenon was analyzed by the Stern-Volmer equation, and the resulting Stern-Volmer constants show that the alkyl functional PPE presents higher sensitivity than the triethylene glycol functional PPE, which was unexpected. The polymer sensors showed the selectivity in that the Stern-Volmer constants for Fe3+ are 2–3 times higher than those for Na+, K+, and Ca2+. Time-resolved photoluminescence spectroscopy revealed that the quenching is static, indicating that there may be coordination between Fe (III) and alkyne/phenyl groups in the PPE backbone. For practical applications, we produced a PPE-containing, fluorescent polydimethylsiloxane (PDMS) pad. Dropping Fe solution like an ink on the pad exhibits a dark stain, demonstrating the scheme of producing Fe-detecting flexible pads for future applications in wearable sensor technology.

Photoluminescence quenching of thermally treated waste-derived carbon dots for selective metal ion sensing

In the present study, carbon-dots (CDs) were derived from the thermal oxidation of an agricultural waste, bitter tea residue, to obtain different sp2/sp3 ratios and electronic structures for metal sensing. The CDs obtained from calcination at 700 °C exhibited the highest photoluminescence (PL) quantum yield (QY) of 11.8% among all the samples treated at different temperatures. These CDs had a high degree of graphitization, which resulted in a strong π-π* electron transition, and hence in a high QY. The strong photoluminescence of the CDs could be used to sense the metal ions Ag+, Sr2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, and Sn2+ by monitoring their PL intensity at an excitation wavelength of 320 nm. The metals inhibited the PL intensity in the order Ag+ > Fe2+, Fe3+, Ni2+ > Sr2+, Co2+, Cu2+, Sn2+, which demonstrated that the CDs exhibited high metal ion detection capability and selectivity. The detection of Fe3+ using CDs was performed in the range of 10–100 ppm with a LOD (limit of detection) value of 0.380 ppm. Theoretical calculations demonstrated that Ag+, Sr2+, and Sn2+ induced charge transfer excitation and that Fe2+ and Ni2+ induced d-d transitions via complexation with the sp2 clusters. The charge transfer excitation and d-d transitions hindered the π-π* transition of the sp2 clusters, leading to a quenching effect. On the other hand, Li+, Na+, and K+ ions did not alter the π-π* transition of the sp2 clusters, resulting in a negligible quenching effect. In summary, the oxidation level and electronic structure of CDs derived from bitter tea residue could be tailored, and the CDs were shown to be a facile, sustainable, and eco-friendly material for metal sensing.

Zn-based complex as a fluorescent probe for selective detection of Fe3+ ion and treatment activity on the primary immune thrombocytopenia through regulating the PD-L1 expression

Zn-based complex as a fluorescent probe for selective detection of Fe3+ ion and treatment activity on the primary immune thrombocytopenia through regulating the PD-L1 expression

A typical 2D covalent organic polymer as multifunctional sensor and assemble a WLED

Luminescent sensors have received extensive attention due to their fast-response and easy-operation and when integrating multifunctions in a sensor, the cost will be reduced substantially. Covalent organic polymers (COPs) as multifunctional luminescent sensor with outstanding performance are still underexplored. In this work, a typical COP named as COP-2 show preponderant performance in the detection of Fe3+, MnO4−, and TNP. COP-2 has the highly efficient ability to selectively detect Fe3+ among the other metal ions, and the limit of the detection (LOD) is 0.89 ​μM, which outperforms the reported covalent organic materials. Anion sensing shows the COP-2 has the highly anti-interference ability and recyclicity to detect MnO4−. Explosive analogs sensing demonstrates that COP-2 owns the superior ability in sensing TNP in the knockdown concentration with 0.0067 ​ppm LOD, which superior to the values in the reported literature. In addition to the above superb sensing performance, COP-2 can be utilized as a white light-emitting diode (WLED) when combined with the commercial blue emission LED and presents a Commission Internationale de l’Eclairage (CIE) coordinate of (0.31, 0.32). These results show the COP-2 not only has an appealing performance in multifunctional luminescent sensing application, but also has a possible application in white light emitting.

A mixed-ligand Zn(II)-coordination polymer: selective detection of Fe3+ ion and promotion activity on the flap transplantation via increasing the vascular endothelial cells proliferation

In the current study, on the basis of 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector, a novel two-dimensional luminescent Zn(II)-coordination polymer whose chemical formula is {[Zn5(timb)4(OH–IPA)4]·2NO3·2DMA·2H2O}n was generated through the reaction between timb and Zn(NO3)2·6H2O in the presence of the OH functionalized isophthalic acid ligand (OH-H2IPA). Furthermore, for the Fe3+ ion, complex 1 reflects superb luminescence sensing performances in the water solution with high selectivity and high sensitivity. The assessment of its promotion activity on the flap transplantation was implemented. Meanwhile, its detailed mechanism was also studied. First of all, the detection of the proliferation activity levels on vascular endothelial cells was conducted with the Cell Counting Kit-8. Subsequently, the signaling pathway of HIPPO activation level was further detected in the vascular endothelial cells after compound treatment.

Stable 2D Zn(II) coordination polymer: selective detection of Fe3+ ion and treatment activity on psoriasis metabolic syndrome

ABSTRACT With the reaction between 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector and Zn(NO3)2 · 6H2O in the presence of a hydroxyl functionalised carboxylate ligand isophthalic acid (OH-H2IPA), a novel luminescent coordination polymer (CP) containing Zn(II) ions as nodes was created through applying the reaction of solvothermal method, and its chemical formula is {[Zn5(timb)4(OH–IPA)4]·2NO3 · 2DMA·2H2O}n (1). Because of complex 1 excellent photoluminescence performances and water stability, it reveals the phenomenon of luminescence turn-off for the Fe3+ cation, and the value of Ksv is 9.59 × 103 M−1 (R2 = 0.9913). The application values of the new compound and its ligands on the psoriasis metabolic syndrome were finally evaluated.

RETRACTED: Two Zn(II) coordination polymers: Selective detection Fe3+ ion and inhibitory activity on the liver cancer viability by regulating the prolyl hydroxylase-3

Abstract In the current study, via utilizing a mixed-ligand method, two new coordination polymers (CPs) of {[Zn5(pmbcd)2(μ3-OH)2(H2O)4(DMF)2]·4DMF}n (1) and {[Zn2(pmbcd)(bpea)2]·2H2O·2DMF}n (2) (in which bpea = 1,2-bis(4-pyridyl)ethane and H4pmbcd = 9,9′-(1,4-phenylenebis(methylene))bis(9H-carbazole-3,6-dicarboxylic acid)) have been successfully prepared using a tetracarboxylate ligand H4pmbcd without or with the present of the second co-ligand bpea. Furthermore, in the water, the complex 1 containing Zn5 clusters exhibits the strong blue luminescence, which can only be selectively quenched via the contaminant Fe3+ ion. For the treatment of liver cancer, the Cell Counting Kit-8 assay was implemented for the assessment of the compounds’ inhibition on the HepG2 liver cancer cells viability. Moreover, the prolyl hydroxylase-3 relative expression in HepG2 liver cancer cells was also detected by the real time reverse transcription polymerase chain reaction.

Zn(ii) and Cd(ii) coordination polymers with a new angular bis-pyridyl-bis-amide: synthesis, structures and sensing properties

Zn(ii) and Cd(ii) coordination polymers that show a 2D double layer with the rare (46·64)-5 L4 topology and a 3D framework with a new (4·5·6)(45·55·69·7·8) topology, respectively, show good selectivity toward the detection of Fe3+ ions.

Electrochemically induced metal- vs. ligand-based redox changes in mackinawite: identification of a Fe3+- and polysulfide-containing intermediate.

Under anaerobic conditions, ferrous iron reacts with sulfide producing FeS, which can then undergo a temperature, redox potential, and pH dependent maturation process resulting in the formation of oxidized mineral phases, such as greigite or pyrite. A greater understanding of this maturation process holds promise for the development of iron-sulfide catalysts, which are known to promote diverse chemical reactions, such as H+, CO2 and NO3- reduction processes. Hampering the full realization of the catalytic potential of FeS, however, is an incomplete knowledge of the molecular and redox processess ocurring between mineral and nanoparticulate phases. Here, we investigated the chemical properties of iron-sulfide by cyclic voltammetry, Raman and X-ray absorption spectroscopic techniques. Tracing oxidative maturation pathways by varying electrode potential, nanoparticulate n(Fe2+S2-)(s) was found to oxidize to a Fe3+ containing FeS phase at -0.5 V vs. Ag/AgCl (pH = 7). In a subsequent oxidation, polysulfides are proposed to give a material that is composed of Fe2+, Fe3+, S2- and polysulfide (Sn2-) species, with its composition described as Fe2+1-3xFe3+2xS2-1-y(Sn2-)y. Thermodynamic properties of model compounds calculated by density functional theory indicate that ligand oxidation occurs in conjunction with structural rearrangements, whereas metal oxidation may occur prior to structural rearrangement. These findings together point to the existence of a metastable FeS phase located at the junction of a metal-based oxidation path between FeS and greigite (Fe2+Fe3+2S2-4) and a ligand-based oxidation path between FeS and pyrite (Fe2+(S2)2-).

A dual-emitting mixed-lanthanide MOF with high water-stability for ratiometric fluorescence sensing of Fe3+ and ascorbic acid

A novel Eu0.07Gd0.03-MOF with high water stability, which can serve as ratiometric fluorescence sensor for “color-change-recover” detection of Fe3+ and ascorbic acid in an aqueous environment.

Fabrication of two-phase Ca2+-doped LaVO4:Eu3+ structures: morphology modification, tunable optical performance and detection of Fe3+ ions with high sensitivity.

Two-phase Ca2+-doped LaVO4:Eu3+ nanocrystals were prepared through a hydrothermal method with the help of SOD CITR and EDTA surfactants. The phase and morphology of the products were characterized by XRD and TEM, and the fluorescence performances were also recorded. The results indicated that Ca2+ ions were doped into the LaVO4:Eu3+ host lattice, impeding the aggregation of the nanocrystals and enhancing the luminescence intensity. The morphology transformation process and luminescence enhancement were systematacially investigated. The fluorescence intensity of the two selected samples could be completely quenched by Fe3+ ions without the disturbance of other ions, with the mechanism being due to the adsorption of Fe3+ ions onto the grains and a subsequent energy transfer from Eu3+ to Fe3+. Therefore, the present two Ca2+-doped LaVO4:Eu3+ samples can be applied as appropriate candidates for detecting Fe3+ ions with agility and sensitivity in aqueous solution.

Ultrasensitive Fe3+ ion detection based on pH-insensitive fluorescent graphene nanosensors in strong acid and neutral media

Schematic illustration of the preparation of FRGO and the detection of Fe3+ ions in strong acid and neutral media.

A Mn(II)-coordination polymer: selective detection of Fe3+ ion and treatment activity on sepsis via reducing the inflammatory cytokines releasing

A Mn(II)-coordination polymer: selective detection of Fe3+ ion and treatment activity on sepsis via reducing the inflammatory cytokines releasing

Physio-biochemical and molecular assessment of Iron (Fe2+) toxicity responses in contrasting indigenous aromatic Joha rice cultivars of Assam, India.

Iron (Fe) toxicity is one of the major abiotic stresses which limits the yield of lowland rice. This study aims to investigate the physiological, biochemical, and molecular aspects of two contrasting aromatic Joha rice, viz., Keteki and Kola Joha of Assam. Oxidative damage caused due to Fe2+ toxicity was quantitatively determined. Fe2+ toxicity in the growth medium increases the level of ROS and anti-oxidative enzyme activity. Along with the aforementioned damage caused due to Fe2+ toxicity, chlorophyll content decreases in both the rice varieties. Detection of Fe3+ and Fe2+ was also conducted by Perls' Prussian and Turnbull blue method, respectively. In addition, spectrophotometric quantification of Fe2+ was determined by 2, 2'-Bipyridyl (Bpy). Above 2.5mM, Fe2+ toxicity was found to be lethal in rice seedlings affecting their total growth and biomass. Gene expression analysis of iron-regulated transporter 1 (OsIRT1), Yellow Stripe-Like 15 (OsYSL15), and ferritin 1 (OsFer1) revealed the differential gene expression over a time period of Fe2+ toxicity. Our study suggested that the different parameters which are considered here can be helpful for the better understanding of how aromatic Joha rice performed under Fe2+ toxicity which can also help to reveal broader aspects that how gene players are involved in the iron homeostasis mechanism in Joha rice in coming future.

High-performance disease diagnosis fluorescent probe based on new type structure YbF3: Er3+@SiO2@GQDs

Due to the difference of temperature and Iron (Fe3+) contents between cancer cells and normal cells, a simple disease diagnosis fluorescent probe integrated with sensitive thermometer and accurate ions detector is constructed based on YbF3: 3%Er3+@SiO2@GQDs (YbSG) core–shell structure. The thermal sensing behaviors of YbF3: Er3+ are investigated by fluorescence intensity ratio (FIR) technology using 4S3/2 and 4F9/2 levels of Er3+ ions irradiated by 980 nm laser. High Yb3+ doped concentrations induce strong energy back transfer (EBT) process between Er3+ and Yb3+, which not only tunes light emission but also effects temperature sensing property by population re-distribution in 4S3/2 and 4F9/2 levels of Er3+ ions. Additionally, fluorescence quenching of graphene quantum dots (GQDs) can reflect Fe3+ ions contents in the range of 0–100 μM excited by 365 nm. The results display that Er3+ doped YbF3 combined with GQDs by introducing an intermediate medium silica layer has a potential application prospect for ultra-sensitive temperature measuring and detection of Fe3+ ions in the field of bio-medicine.

Study on the Development of a Cyclohexane Based Tripodal Molecular Device as "OFF-ON-OFF" pH Sensor and Fluorescent Iron Sensor

Background: Iron is an essential transition metal which is indispensable for life processes like oxygen transport and metabolism, electron transfer etc. However, misregulated iron is responsible for disease like anemia, hemochromatosis, Alzheimer’s and Parkinson’s disease. In order to encounter these diseases, a better understanding is needed of its role in misregulation. Fluorescent iron sensors could help provide this information. The new chemosensor developed by linking a cyclohexane unit with three 8-hydroxyquinoline provides selective detection of iron in numerous biological and environmental samples. Methods: The Uv-visible and fluorescence spectroscopy in combination with pH measurements will mainly be used for the study. Theoretical studies at DFT level will be used to validate the method and explain the theory behind the experiments. Results: The study of electronic spectra of the chelator, HQCC, reveals the appearance of a band at 262 nm along with a weak band at 335 nm due to π- π* and n- π* transitions respectively. Upon excitation with 335 nm, the ligand fluoresces at 388 nm wavelength. The intensity of the emission was affected in presence of metal ions, with maximum deviation for Fe(III). Selectivity studies showed that Fe(III) is more selective as compared to the biologically relevant metal ions viz., Al(III), Fe(III), Cr(III), Co(II), Fe(II), Ni(II), Zn(II), Cu(II), Mn(II) and Pb(II). pH dependent studies implied that the fluorescence intensity was highest at pH ~8.0, whereas maximum quenching for iron-HQCC system was observed at pH 7.4. The binding studies from the B-H plot confirms the formation of 1:1 complex with association constant of 5.95 × 106. The results obtained from experiments were in agreement with that obtained from the DFT and TD-DFT studies. Conclusion: A novel tripodal chelator based on 8-hydroxyquinoline and symmetric cyclohexane scaffold was successfully developed. In addition to the excellence of the ligand to be employed as a promising sensitive fluorescent probe for easy detection of Fe3+ions at the physiological pH with very low concentration (7.5 x 10-5 molL-1), the new ligand can be used as an OFF-ON-OFF pH sensor. Fe(III) encapsulation along with 1:1 ML-complexation formation have been established. Theoretical studies confirm a d-PET mechanism for the fluorescence quenching. DFT studies revealed that the neutral form of the ligand is less reactive than its protonated or the deprotonated form.