Detection Of Fe3 Research Articles

A colorimetric sensor based on 2,3-bis(6-chloropyridin-2-yl)-6-fluoroquinoxaline for naked-eye detection of Iron (III) and its application in real sample analysis

Iron ions are crucial for numerous biological processes, and the levels of these ions have a significant impact on human well-being. Hence, it is essential to identify the level of Iron ions using a suitable technique. A new colorimetric sensor, namely “2,3-bis(6-chloropyridin-2-yl)-6-fluoroquinoxaline” (CF), has been introduced to detect Fe3+ through naked-eye observation. The sensor exhibits remarkable specificity towards Fe3+ compared to other metal ions in aqueous environments. Furthermore, it undergoes a substantial color change from colorless to yellow, which is visible without needing additional equipment. The complex formation was proposed to be in 1:1 ratio based on the Job’s plot and molar ratio plot. The maximum sensitivity of CF towards Fe3+ was found at pH 6 to 8. Minimal or negligible interference was noticed from different metal ions in the detection of Fe3+. The binding constant using Benesi-Hildebrand was estimated at 1.434 × 104 M−1. Gibbs free energy was determined –23.728 kJ/Mol. The LOD and LOQ were calculated at 0.378 and 1.26 µM, respectively. The probe CF was utilized to recover Fe3+ in tap water, resulting in recovery percentages ranging from 99.44 to 103.61. This indicates that the CF has the ability to identify Fe3+ in environmental samples

Curcumin suppresses colorectal cancer by induction of ferroptosis via regulation of p53 and solute carrier family 7 member 11/glutathione/glutathione peroxidase 4 signaling axis.

Driven by iron-dependent lipid peroxidation, ferroptosis is regulated by p53 and solute carrier family 7 member 11 (SLC7A11)/glutathione/glutathione peroxidase 4 (GPX4) axis in colorectal cancer (CRC). This study aimed to investigate the influence of curcumin (CUR) on ferroptosis in CRC. The efficacies of CUR on the malignant phenotype of CRC cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, wound healing, and clonogenic assays. The effects of CUR on ferroptosis of CRC cells were evaluated by transmission electron microscopy, lactate dehydrogenase release assay, Fe2+ staining, and analyses of reactive oxygen species, lipid peroxide, malondialdehyde, and glutathione levels. CUR's targets in ferroptosis were predicted by network pharmacological study and molecular docking. With SW620 xenograft tumors, the efficacy of CUR on CRC was investigated, and the effects of CUR on ferroptosis were assessed by detection of Fe2+, malondialdehyde, and glutathione levels. The effects of CUR on expressions of p53, SLC7A11, and GPX4 in CRC cells and tumors were analyzed by quantitative reverse transcription-polymerase chain reaction, western blotting, and immunohistochemistry. CUR suppressed the proliferation, migration, and clonogenesis of CRC cells and xenograft tumor growth by causing ferroptosis, with enhanced lactate dehydrogenase release and Fe2+, reactive oxygen species, lipid peroxide, and malondialdehyde levels, but attenuated glutathione level in CRC. In silico study indicated that CUR may bind p53, SLC7A11, and GPX4, consolidated by that CUR heightened p53 but attenuated SLC7A11 and GPX4 mRNA and protein levels in CRC. CUR may exert an inhibitory effect on CRC by inducing ferroptosis via regulation of p53 and SLC7A11/glutathione/GPX4 axis.

Investigation of the luminescence mechanism of multi-color nitrogen-doped carbon quantum dots and their application in the detection of Fe3+

This study reports the successful preparation of nitrogen-doped carbon quantum dots (N-CQDs) with a quantum yield of 15 % utilizing the hydrothermal method. Citric acid was employed as the carbon source, while 1,3-Diamino-2-propanol was utilized as the dopant. It was discovered that the emission of synthesized N-CQDs was dependent on concentration and excitation. By altering the N-CQDs concentration, the fluorescence emission peak was shifted from 453 to 574 nm, causing the emission to transition from blue to orange. The presence of multiple fluorescence emission centers within N-CQDs was confirmed through two-dimensional fluorescence matrix scanning. As the concentration of N-CQDs increased, the distance between these centers decreased, ultimately leading to aggregation. The energy or electrons were transferred as a result of the surface functional groups' interaction, which ultimately causes the fluorescence emission peak to shift to the red. Furthermore, an increase in concentration results in the formation of larger aggregates and larger sp2 carbon domains, ultimately resulting in longer wavelengths. Because of the convenience of use, high sensitivity, and rapid response of the fluorescent probe detection approach, multi-color N-CQDs with tunable concentration were used for the identification of Fe3+, with a 10–200 μM linear detection range and limits of detection (LOD) of 0.56 μM.

Application of green tea residue-derived carbon dots in the detection of Fe3+ ions and imaging of Caco-2 cells

In this study, we successfully synthesized green luminescent carbon dots by using green tea residue as the precursor of carbon source. Based on the internal filter effect (IFE), the fluorescence emission intensity of the probe decreased significantly with the increase of Fe3 + concentration. Based on this, a linear relationship between Fe3 + concentration and the fluorescence emission intensity of the probe was established to semi-quantitatively detect Fe3 +. The results showed that the linear range was 1–400 μM, and the detection limit was 3.58 μM. In addition, the probe was further applied to actual samples, and it was found that the recovery rate was between 97.75% and 104.59%, and the relative standard deviation was below 1.81%. These findings underscore the considerable potential of the carbon dots for practical Fe3+ detection applications. In a further application, the fluorescent carbon dots were diluted and directly employed to stain Caco-2 cells. Remarkably, even after 10 and 20-fold dilutions, the Caco-2 cells displayed vivid fluorescence at the green excitation wavelength. This outcome suggests a promising avenue for the application of fluorescent carbon dots in the field of biology.

Fabrication of chitosan-based fluorescent hydrogel membranes cross-linked with bisbenzaldehyde for efficient selective detection and adsorption of Fe2+

Chitosan, as a natural biomass material, is green, recyclable, sustainable and well biocompatible. The molecular chain is rich in active groups such as amino and hydroxyl groups, and its preparation of fluorescent probes has the advantages of biocompatibility and efficient detection performance. In this study, a bis(benzaldehyde) (BHD) fluorescent functional molecule was designed. Then a series of fluorescent chitosan-based hydrogel films (CSBHD) were prepared using chitosan as raw material and BHD as cross-linking agent. As a fluorescent probe for metal ions, CSBHD was able to efficiently detect Fe2+ with a linear correlation of fluorescence intensity in the range of 0–160 μM, and the limit of detection (LOD) was 0.55 μM. Moreover, it has excellent adsorption performance for Fe2+ ions, with a maximum adsorption capacity of 223.5 g/mg at 500 mg/L Fe2+ concentration. Finally, we characterised the structure and microscopic morphology of CSBHD films and found that CSBHD as a hydrogel film has a high cross-linking density, good water resistance, excellent thermal stability, strong resistance to swelling, and excellent stability in cycling tests. Hence, it has great potential for application in adsorption and detection of Fe2+ ions. It also provides a good strategy for the application of chitosan based fluorescent probe materials in environmental monitoring and heavy metal ion adsorption.

A quinoline derivative-based supramolecular gel for fluorescence ‘turn-off’ detection of Fe3+ and Cu2+

In this research, we synthesized and constructed a novel gelator (named QN) combining quinoline and naphthalene that self-assembled in N, N-dimethylformamide (DMF) to form a stable supramolecular gel (named OQN). Under UV light, gel OQN exhibited extremely bright yellow fluorescence. The gel OQN showed excellent sensing performance for both Fe3+ and Cu2+, with a fluorescence ‘turn-off’ detection mechanism and the lowest detection limit of 7.58 × 10−8 M and 1.51 × 10−8 M, respectively. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, x-ray powder diffraction (XRD), rheological measurements, x-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy were used to characterize the gel OQN. The OQN ion-responsive membrane created is an excellent fluorescent writing material.

MiR-208a-3p regulated by circUQCRC2 suppresses ischemia/reperfusion-induced acute kidney injury by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis.

Background : Acute kidney injury (AKI) is a prevalent clinical syndrome with persistent kidney dysfunction. Renal ischemia/reperfusion (I/R) injury is a major cause of AKI. miR-208a-3p overexpression attenuated myocardial I/R injury. This study aims to investigate the role and mechanism of miR-208a-3p in I/R-induced AKI. Methods : AKI models were established using hypoxia/reoxygenation (H/R)-exposed tubule epithelial cell HK-2 and I/R-induced mice. The function and mechanism of miR-208a-3p were investigated by gain- or loss-of-function methods using real-time PCR, CCK-8, flow cytometry, ELISA, western blot, hematoxylin-eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, detection of Fe 2+ , reactive oxygen species, blood urea nitrogen and creatinine, and luciferase reporter assay. Results : miR-208a-3p expression was suppressed, while the expression of CELF2 and circular RNA ubiquinol-cytochrome c reductase core protein 2 (circUQCRC2) was increased in both AKI models. miR-208a-3p upregulation or circUQCRC2 silencing increased the viability, decreased the levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), reduced apoptosis and contents of Fe 2+ and reactive oxygen species, elevated expression of GPX4 and SLC7A11, and reduced ACSL4 expression in H/R-stimulated HK-2 cells. In addition, miR-208a-3p improved kidney function by alleviating renal injury, apoptosis, inflammation, and ferroptosis in AKI mouse model. CELF2 was a target gene of miR-208a-3p, which was negatively modulated by circUQCRC2. Overexpression of CELF2 blocked the function of miR-208a-3p upregulation or circUQCRC2 silencing on H/R-treated HK-2 cells. Moreover, the effects of circUQCRC2 downregulation on H/R-injured cells were also reversed by miR-208a-3p inhibitor. Conclusions : miR-208a-3p regulated by circUQCRC2 could attenuate I/R-induced AKI by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis. This study provides potential therapeutic targets for I/R-induced AKI.

Silicon-Doped Carbon Dots Crosslinked Carboxymethyl Cellulose Gel: Detection and Adsorption of Fe3.

The excessive emission of iron will pollute the environment and harm human health, so the fluorescence detection and adsorption of Fe3+ are of great significance. In the field of water treatment, cellulose-based gels have attracted wide attention due to their excellent properties and environmental friendliness. If carbon dots are used as a crosslinking agent to form a gel with cellulose, it can not only improve mechanical properties but also show good biocompatibility, reactivity, and fluorescence properties. In this study, silicon-doped carbon dots/carboxymethyl cellulose gel (DCG) was successfully prepared by chemically crosslinking biomass-derived silicon-doped carbon dots with carboxymethyl cellulose. The abundant crosslinking points endow the gel with excellent mechanical properties, with a compressive strength reaching 294 kPa. In the experiment on adsorbing Fe3+, the theoretical adsorption capacity reached 125.30 mg/g. The introduction of silicon-doped carbon dots confers the gel with excellent fluorescence properties and a good selective response to Fe3+. It exhibits a good linear relationship within the concentration range of 0-100 mg/L, with a detection limit of 0.6595 mg/L. DCG appears to be a good application prospect in the adsorption and detection of Fe3+.

A fluorescence sensor based on BSA modified sulfur nanosheets for sequential detection Fe3+ and salicylic acid

Sulfur nanosheets (S-NSs) have received increasing attention in biochemistry fielded due to adequate inherent antibacterial, antifungal activities, outstanding stability and reusability. The electron transfer between the iron ions (Fe3+) and S-NSs brings S-NSs aggregation lead to the fluorescence intensity of S-NSs decreases in a wide linear concentration range from 12 to 108 μM. More interestingly, the quenched fluorescence of S-NSs/Fe3+ could be recovered by salicylic acid (SA) in a linear range of 8–80 μM because of a stable complex could be form between SA and Fe3+and the proposed sensor for SA showed the outstanding advantages of simplicity, specificity, and fast. The method included environmentally friendly, low-cost, convenient, and wide linear range, which makes it a novel method for routine applications for Fe3+ and SA detection.

A sensitive sensor based on carbon dots for the determination of Fe3+ and ascorbic acid in foods.

To develop a feasible, sensitive, and essential sensor is important for the identification of Fe3+ ions and ascorbic acid (AA). Herein, highly fluorescent heteroatom co-doped carbon dots (N,S-CDs) with a quantum yield (QY) of 24.6% were synthesized, using hydrothermal treatment of L-cysteine (Cys) and 1-amino-2-naphthol-4-sulfonic acid (ANSA). The fluorescence emission of the as-prepared N,S-CDs was quenched strongly by Fe3+ ions, and this was further recovered by the reduction effect of AA on Fe3+. Based on this, continuous fluorescence sensing of Fe3+ and AA with an "on-off-on" style was developed. The detection of Fe3+ and AA were in relatively wider linear ranges of 5.00-105 μmol L-1 and 4.97-54.8 μmol L-1, with a detection limit of 0.10 μmol L-1 and 2.4 nmol L-1 (S/N = 3), respectively. Then, the N,S-CDs were successfully used to measure Fe3+ ions and AA in some daily food samples, and this method exhibited some advantages over most other reported techniques in the term of response speed, quantum yield, and detection limit.

S-doped g-C3N4 for fluorescence sensing of Fe3 + and photocatalytic dye degradation under solar light

Sulfur doped graphitic carbon nitride nanosheets were synthesized via polycondensation reaction of urea-thiourea mixture. Structure and morphology were characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), and XPS (X-ray Photoelectron Spectroscopy). DRS (diffuse reflectance spectroscopy), PL (Photoluminescence spectroscopy) and time-resolved fluorescence decay spectra were used to study the optical characteristics. The photocatalytic dye degradation of Rhodamine B (RhB) in the presence of as-synthesized catalysts was investigated with the help of a UV–visible spectrophotometer. The photocatalytic activity of carbon nitride prepared from urea-thiourea mixture is almost three times higher than that of the pure sample. The detection of Fe3+ was also investigated by using the fluorescence sensing method. The as-synthesized samples hold greater selectivity and sensitivity for fluorescence sensing of Fe3+within a range of 0–3 µM. This range is comparable to the performance of other Fe3+ fluorescent probes previously reported.

Preparation of high intensity transparent fluorescent corn husk and its detection of Fe3+

Iron is one of the most critical elements in the human body and has a close relationship with human life. Hence, it is imperative to conduct tests for iron ions. Corn husk, being a biomass material that is widely available, is abundant in cellulose. Consequently, in this study, a fluorescent probe (COHS) was devised and synthesized, utilizing a flavonoid backbone. Then, fluorescent corn husks (ACH-COHS) with hydrophobicity and transparency were prepared by bonding COHS with cellulose in corn husks through physical adsorption and hydrogen bonding. The tensile strengths of natural corn husk (NCH), delignified corn husk (ACH), and ACH-COHS were 6.98 MPa, 23.2 MPa, and 22.2 MPa, respectively. The tensile strength of ACH-COHS is approximately 3.2 times that of NCH. The elongation at break of NCH, ACH, and ACH-COHS was 1.84 %, 7.30 %, and 6.82 %, respectively. Compared to NCH, the elongation at break of ACH-COHS increased by 4.98 %. The results showed that the mechanical properties of ACH-COHS were better than those of NCH, and ACH-loaded COHS had less effect on its mechanical properties. Fe3+ had a quenching effect on ACH-COHS with a response time of 90 s and a detection limit of 0.08 μM. The detection mechanism of ACH-COHS was verified by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and Mass spectrometry. This study presents a new and sustainable method to visualize and detect Fe3+.

Dual responsive cellulose-based fluorescent material fabricated in a CO2 switchable solvent for multifunctional applications

Fabrication of multi-responsive fluorescent sensors for real-time and visual monitoring or detection is practical and challenging. Herein, a novel cellulose-based fluorescent functional material with dual-responsive properties arising from two different functional sites was successfully designed and prepared in a CO2 switchable solvent. Cellulose was effectively dissolved in this solvent and easily functionalized by successively grafting poly (lactic acid) and 7-hydroxy-4-trifluoromethyl coumarin (HFC) onto the cellulose backbone, resulting in C-g-PLLA/HFC with good processibility and fluorescence quenching response (turn off) towards Fe3+ due to the coordination of Fe3+ with the carbonate linkage. Acetylation of HFC under microwave-assisted conditions gave rise to C-g-PLLA/HFC-Ac which showed fluorescence enhancement response (turn on) to various organic amines because of the removal of the acetyl group by aminolysis reaction. Therefore, they could be respectively used for selective identification and detection of Fe3+, and real-time, accurate and visual monitoring of aquatic product freshness. Furthermore, an interesting application for irreversible information encryption was demonstrated by combining the dual-responsive property. This study suggests a new strategy for constructing cellulose-based functional material with multiple responsiveness and applications.

Aggregation enhanced emissive orange carbon dots for information encryption and detection of Fe3+ and tetracycline

In this study, N-doped fluorescent carbon dots with aggregation enhanced emission (N-CDs) were synthesized by a simple and rapid microwave-assisted method using o-phenylenediamine (OPD) and urea as raw materials and water as solvent. The fluorescence quantum yield of N-CDs was 20.64 %. N-CDs can be applied as invisible inks for message encryption. Furthermore, the fluorescence intensity of N-CDs can be quenched by Fe3+ and enhanced by tetracycline (TC). Therefore, two fluorescent probes were simultaneously designed in this study. Namely, “turn-off” fluorescence probe for Fe3+ and “turn-on” fluorescence probe for TC. The linear detection range of Fe3+ is from 1 to 70 μM, and detection limit is 0.1011 μM; the linear detection range of TC is from 0.1 to 10 μM, and the detection limit can be as low as 0.0555 μM. In this paper, the mutual interference between Fe3+ and TC was investigated for the first time. The detection of Fe3+ and TC was made more accurate by optimizing pH conditions and adding masking agent.

New complexes based on reduced Schiff base carboxylic acid ligand: Electric properties, fluorescence properties and detection of Fe3+

Two kinds of complexes [M(L)(H2O)]n(1–3) [M = Cd(1), Co(2), Mn(3)] and {[Ln(L)(HL)]·(H2O)3}n (4–6) [Ln = Sm(4), Gd(5), Tm(6)] were dexterously constructed via reduced Schiff base carboxylic acid ligand (H2L=5-((4-(1H-imidazol-1-yl)benzyl)amino)isophthalic acid) under solvothermal reactions. Complexes 1–3 are two-dimensional (2D) framework consisted of binuclear [M2O10N2] building unit. Complexes 4–6 are three-dimensional (3D) network structure with ecu topological net. Importantly, with the 2D layered structure complex 3 as the electrode material for a supercapacitor has a maximum specific capacitance is 412.3 F·g−1 at a current density of 1 A·g−1, and even at 5 A·g−1, the specific capacitance retention is about 59.2 % of the initial capacitance. The electrochemical property ascribed attributed to the inherent properties of complex 3, including its layered structure and favorable exposed facets. Remarkably, the exploration of luminescence studies demonstrated that complex 1 has an outstanding capacity for detecting Fe3+ with excellent selectivity and sensitivity, where individual quenching efficiency Ksv (1.18 × 103 M−1) and detection limit (2.1 × 10−5 M) were regarded as the excellent coordination polymers sensors for detecting Fe3+.

A Sensitive Fluorescence Probe for the Trace Detection of Fe(III) Based on a Post‐Synthesis‐Modified Copper‐Based Metal‐Organic Framework

AbstractThis work presents the generation of a post‐synthetically modified Metal‐Organic Framework (MOF), denoted as Cu‐BDC‐NH2‐DHB, achieved through a Schiff‐base reaction by converting the pendant amino group in pristine Cu‐BDC‐NH2 MOF to an imine group using 3,4‐dihydroxybenzaldehyde (DHB). The resulting material exhibited exceptional luminescence and fluorescence stability in water, prompting investigation into its potential as a metal sensor. Fluorescence tests revealed that Cu‐BDC‐NH2‐DHB could be transformed into a highly selective and sensitive sensor for detecting Fe3+ ions amid co‐interfering metal ions, with a remarkable detection limit of 3.08 μM. Furthermore, the results demonstrated that Fe3+ induced a rapid and strong quenching effect, with a reaction time measured in seconds. This research provides a promising technique for the facile and immediate detection of Fe3+ ions in practical applications.

Integration of N, P-doped carbon quantum dots with hydrogel as a solid-phase fluorescent probe for adsorption and detection of Fe3+

In this work, a novel nitrogen-phosphorus co-doped carbon quantum dots (N, P-CQDs) hydrogel was developed utilizing the as-synthesized N, P-CQDs and acrylamide (AM) with the existence of ammonium persulfate and N, N′-methylene bisacrylamide (N-MBA). In consistent with pure N, P-CQDs, the N, P-CQDs hydrogel also shows a dramatic fluorescence property with maximum emission wavelength of 440 nm, which can also be quenched after adsorbing iron ions (Fe3+). When the concentration of Fe3+ is 0–6 mmol l−1, a better linear relationship between Fe3+ concentration and the fluorescence intensities can be easily obtained. Additionally, the N, P-CQDs hydrogel exhibits better recyclability. This confirms that the N, P-CQDs hydrogel can be used for adsorbing and detecting Fe3+ in aqueous with on–off–on mode. The fluorescence quenching mainly involves three procedures including the adsorption of Fe3+ by hydrogel, integration of Fe3+ with N, P-CQDs and the transportation of conjugate electrons in N, P-CQDs to the vacant orbits of Fe3+ and the adsorption process follows a pseudo-second-order kinetic model confirmed in the Freundlich isotherm model. In conclusion, this work provides a novel route for synchronously removing and detecting the metal ions in aqueous by integrating N, P-CQDs with hydrogel with better recyclability.

Fluorescent probe based on acyclic cucurbituril to detect Fe3+ ions in living cells

Fe3+ is an essential element for human body, misregulation of which in cell are concerned with serious diseases. It is very meaningful to detect Fe3+ in living cells. Here, a novel fluorescent probe (Py-ACB) based on acyclic cucurbituril and pyrene was synthesized. Py-ACB exhibits high selectivity and sensitivity to Fe3+, Fe3+ is coordinated with the carbonyl groups and oxygen atoms of Py-ACB, resulting in reverse photo-induced electron transfer (reverse PET) from pyrene unit to the carbonyl oxygen atoms to induce fluorescence quenching. The binding constant and detection limits of Fe3+ recognized by Py-ACB are 9.26 × 104 M−1 and 2.51 × 10−8 M, respectively, and Py-ACB showed high response speed to Fe3+. More importantly, the probe Py-ACB showed strong fluorescence emission in living cell, which allowed the detection of Fe3+ in live cells by bioimaging.

LaVO4: Eu3+ nano-islands onto silica for achieving fluorescence enhancement and their detection of Fe3+ ions and anti-counterfeiting applications

Rare earth (RE) composite fluorescent materials are favored by researchers in the field of anti-counterfeiting and ion sensing due to their fascinating optical properties. Ultra-small RE fluorescent nanoparticles are anchored on inorganic carriers by a simple preparation method to improve luminous intensity and hydrophilicity, which has not been explored yet. Herein, LaVO4: Eu3+ nano-islands anchored on silica with high fluorescence intensity and easy formation of stable colloidal solution is designed. Through a simple and mild hydrothermal approach, ultra-small LaVO4: Eu3+ nano-islands are highly dispersed on the surface of hierarchical hollow silica sphere (HHSS) to expose more luminescent centers. Remarkably, the stable HHSS@LaVO4: Eu3+ colloidal solution displayed highly sensitive and selective sensor for Fe3+ ions. The “island-sea synergy” structure formed by the LaVO4: Eu3+ nano-islands and the surrounding silica surface makes HHSS@LaVO4: Eu3+ to be an outstanding sensor for the effective detection of iron ions in water. In addition, HHSS@LaVO4: Eu3+ phosphor exhibit unique properties for anti-counterfeiting and encryption applications. These findings provide a promising strategy for the carrierisation of RE luminescent materials to improve optical properties and enable broader applications.

The impact of small organic molecules on Fe(II) coagulation: Facilitating vs. shielding mechanisms on charge transfer

During the Fe(II) coagulation process, organics can significantly alter the structure of formed flocs, thereby influencing their efficacy in water treatment. However, the underlying mechanisms are not fully understood. This study investigates the impact of small organic molecules (SOM) on Fe(II) coagulation using serine, cysteine, histidine, and citric acid as examples. Results demonstrate that different SOM can significantly change the coagulation behavior by forming particles with distinct nanostructures, including flake-shaped γ-FeOOH, spherical γ-FeOOH, and ferrihydrite globules. The detection of Fe2+ in solution partially explains these phenomena, as Fe2+ can catalyze lattice rearrangement through charge transfer. By controlling the oxidation rate of Fe2+, SOM can influence the structure of flocs: cysteine and serine prolong the existence time of Fe2+ and promote the formation of highly crystalline γ-FeOOH, while citric acid accelerates Fe2+ oxidation, resulting in the opposite effect. However, histidine, despite delaying the oxidation of Fe2+, inhibits the formation of crystalline minerals, leading to the presence of flocs containing spherical γ-FeOOH. Mediated electrochemical analyses indicate that this is due to the adsorption of SOM on flocs, which hinders the effective entry of Fe2+ into the solid phase and disrupts the charge transfer. This study demonstrates that SOM can affect the interaction between Fe2+ and the nanostructure of flocs in two ways: directly influencing the oxidation rate of Fe2+ and indirectly interfering with the charge transfer between flocs and free Fe2+, which highlights the critical role of Fe(II)-Fe(III) charge transfer in coagulation and provides new possibilities for analyzing more complex organics-coagulation systems.