Experimental and Theoretical Studies of Glyphosate Detection in Water by an Europium Luminescent Complex and Effective Adsorption by HKUST-1 and IRMOF-3

An exceptional water stable terbium-based metal-organic framework for selective detection of pesticides

A terbium-based metal-organic framework (MOF) with exceptional water stability for highly selective detection of pesticide thiamethoxam (TMX) in aqueous solution is reported. To date, most reported lanthanide metal-organic frameworks (Ln-MOFs) still exhibit poor water stability, which may limit their practical applications in bio-sensing and detecting pollutants in environmental water samples. In this work, a Tb-MOF [Tb(BDC)1.5(DEF)·0.5H2O] n (1, BDC = 1,4-benzene dicarboxylate, DEF = N,N-diethylformamide) was prepared by hydrothermal reactions of 1,4-benzenedicarboxylic acid with the corresponding rare earth ions of Tb3+. Impressively, water stability surveys of compound 1 indicated that it maintained at least 90% of its emission intensity after storage in water for several months. This characteristic of long water stability is unusual as compared to other Ln-MOFs, making compound 1 an excellent candidate for sensing applications in the aqueous phase. In particular, the green emission of compound 1 could be quenched by the pesticide thiamethoxam (TMX), which was attributed to both the static and dynamic quenching processes based on an upward-curving Stern-Volmer plot. The quenching mechanism was speculatively attributed to the inner filter effect combined with the complex formation based on the electrostatic interaction of compound 1 and TMX, resulting in the promotion of the quenching efficiency. Finally, compound 1 was demonstrated to detect TMX in aqueous solution with rapid response and high selectivity.

Crumpled graphene fully decorated with nickel-based nanoparticles applied in glyphosate detection

Glyphosate (Glyp), a widely used herbicide, has raised significant concerns regarding its toxicological effects and potential risks to human health, particularly concerning water pollution. Hence, there is a critical need to monitor glyphosate levels in water bodies. This study introduces a novel approach for electrochemically detecting glyphosate in aqueous environments using crumpled graphene decorated with nickel-based nanoparticles (Ni:CG) synthesized in a single step. Cyclic voltammetry and chronoamperometry techniques were employed for detection. The cyclic voltammetry analysis revealed an impressive linear range with detection and quantification limits of 2.0 × 10-9 M and 6.0 × 10-9 M, respectively. Additionally, the method demonstrated excellent accuracy and precision at low concentrations, as evidenced by successful glyphosate recovery from distilled-deionized water and spike-and-recovery tests, at a significant level of 99.9%. Furthermore, interference tests conducted via chronoamperometry on the presence of Cu2+, Co2+, and Fe3+ cations showcased the superior performance of the Ni:CG electrochemical sensor. The synthesis of crumpled graphene-/nickel-based composites offers a promising avenue for the future of on-site glyphosate detection, presenting a robust and efficient solution to environmental challenges.

Isoreticular Metal-Organic Framework-3 (IRMOF-3): From Experimental Preparation, Functionalized Modification to Practical Applications

Isoreticular metal-organic framework-3 (IRMOF-3), a porous coordination polymer, is an MOF material with the characteristics of a large specific surface area and adjustable pore size. Due to the existence of the active amino group (-NH2) on the organic ligand, IRMOF-3 has more extensive research and application potential. Herein, the main preparation methods of IRMOF-3 in existing research were compared and discussed first. Second, we classified and summarized the functionalization modification of IRMOF-3 based on different reaction mechanisms. In addition, the expanded research and progress of IRMOF-3 and their derivatives in catalysis, hydrogen storage, material adsorption and separation, carrier materials, and fluorescence detection were discussed from an application perspective. Moreover, the industrialization prospect of IRMOF-3 and the pressing problems in its practical application were analyzed and prospected. This review is expected to provide a reference for the design and application of more new nanomaterials based on IRMOF-3 to develop more advanced functional materials in industrial production and engineering applications.

"On-On-Off" Recyclable Fluorescence Battery for Direct and Selective Detection of Glyphosate and Cu2

Residues of environmental organophosphorus pesticides (OPs) will seriously endanger human health. Most reported OP sensors utilized the restrictions capacity of OPs on the catalytic capacity of acetylcholinesterase (AChE) to acetylthiocholine chloride (ATCh), which suffers from high costs, weak stability, long reaction time, and unrecyclable. Herein, a recyclable strategy was proposed for selective and sensitive detection of glyphosate (Gly). The weak fluorescence of UIO-66-NH2 at 450 nm was enhanced almost 10-fold after reacting with Gly because of the rotation-restricted emission enhancement mechanism. Moreover, inspired by the process of charging and discharging the batteries, we introduced Cu2+ to chelate with Gly. Because of the strong chelation between Cu2+ and Gly, the Gly was removed from UIO-66-NH2, which resulted in the quenching of fluorescence intensity and making UIO-66-NH2 recycle. This method proposed is fast, recyclable, easily conducted, and with a low 0.33 μM LOD in dd H2O based on 3σ/S. The recovery rates of Gly in tap water ranged from 93.07 to 104.35% within a satisfied 7.75% RSD. The Cu2+ LOD is 0.01 mM based on 3σ/S and 94.37-118.34% recovery rates within 6.48% RSD in tap water. We believe that the findings in this work provide a meaningful and promising strategy to detect Gly and Cu2+ in real samples. This sensor first successfully achieves the recycling use of the material in OP fluorescence detection, which greatly decreases the cost of the designed sensor and reduces the possibility of secondary pollution to the environment, broadens a new circulation dimension of fluorescence detection methods in detecting OPs, and has the potential to remove glyphosate from water. It also provides a method to utilize functionalized metal-organic frameworks to establish various sensors.

Luminescent Supramolecular Metallogels: Drug Loading and Eu(III) as Structural Probe

Supramolecular metallogels combine the rheological properties of gels with the color, magnetism, and other properties of metal ions. Lanthanide ions such as Eu(III) can be valuable components of metallogels due to their fascinating luminescence. In this work, we combine Eu(III) and iminodiacetic acid (IDA) into luminescent hydrogels. We investigate the tailoring of the rheological properties of these gels by changes in their metal:ligand ratio. Further, we use the highly sensitive Eu(III) luminescence to obtain information about the chemical structure of the materials. In special, we take advantage of computational calculations to employ an indirect method for structural elucidation, in which the simulated luminescent properties of candidate structures are matched to the experimental data. With this strategy, we can propose molecular structures for different EuIDA gels. We also explore the usage of these gels for the loading of bioactive molecules such as OXA, observing that its aldose reductase activity remains present in the gel. We envision that the findings from this work could inspire the development of luminescent hydrogels with tunable rheology for applications such as 3D printing and imaging-guided drug delivery platforms. Finally, Eu(III) emission-based structural elucidation could be a powerful tool in the characterization of advanced materials.

Bioengineering of Cu2O structured macro-biotemplate for the ultra-efficient and selective hand-retrieval of glyphosate from agro-farms

Glyphosate (Gly) is a massively utilized toxic herbicide exceeding its statutory restrictions, causing adverse environmental and health impacts. Engineered nanomaterials, even though are integral to remediate Gly, their practical use is limited due to time and energy driven purifications, and negative environmental impacts. Here, a 3D wide area (~1.6 ± 0.4 cm2) Cu2O nanoparticle supported biotemplate is designed using fish-scale wastes as a sustainable approach for the ultra-efficient and selective hand-remediation of Gly from real-time samples from agro-farms. While the innate metal binding and reducing ability of collagenous scales aided self-synthesis cum grafting of Cu2O, the selective binding potential of Cu2O to Gly facilitated its hand-retrieval; as assessed using optical characterizations, Fourier transform infrared spectroscopy, thermogravimetric analysis and liquid chromatography mass spectrometry. Optimization studies revealed extractions of diverse pay-loads of Gly between 0.1 μg/mL to 40 μg/mL per 80 mg biotemplate grafted with ~6.354 μg of sub-5 nm Cu2O and was exponential to the number of Cu2O@biotemplates. Even though pH and surfactant didn't have any impact on the adsorption of Gly to the Cu2O@biotemplates, increase in the ionic strength led to a drastic increase in the adsorption. Density function theory simulations unveiled the involvement of phosphonic and carboxylic groups of Gly for interaction with Cu2O with a bond length of 1.826 Å and 1.833 Å, respectively. Overall, our sustainably generated, cost-efficient, hand-retrievable Cu2O supported biotemplate can be generalized to extract diverse organophosphorus toxins from agro-farms and other sewage embodiments. SYNOPSIS: Glyphosate is an excessively applied herbicide with potent health hazards and carcinogenicity. Thus, a hand removable Cu2O-supported biotemplate to selectively and efficiently remediate glyphosate from irrigation water is developed.

Cu2+ assisted carnation-like fluorescent metal-organic framework for triple-mode detection of glyphosate in food samples

Herein, by employing a novel synthesized ligand H₂L, a flower-like luminescent metal-organic framework IRMOF-3-L was constructed for developing a triple-mode sensor for glyphosate (Glyp) detection. The ligand H₂L was designed to contain three functional parts, which endowed the resulted IRMOF-3-L with peroxidase-like activity and unique fluorescence property, as well as specific combining capacity for Cu²⁺ to quench its fluorescence. The quenched fluorescence of IRMOF-3-L/Cu²⁺ could be recovered by Glyp to realize fluorescence detection of Glyp. Besides, the peroxidase activity of IRMOF-3-L/Cu²⁺ could also be inhibited by Glyp, and result in the decrease of catalysate oxTMB, concurrently reducing the changes of colorimetric and SERS signal. Therefore, the fluorescent/colorimetric/SERS triple-mode based detection of Glyp was favorably realized, and the detection limits were calculated as low as 0.738, 2.26 and 0.186 nM, respectively. Furthermore, a portable test strips-smartphone sensing platform was constructed for point of care testing of Glyp in food samples.

Detection of different chemical moieties in aqueous media by luminescent Europium as sensor

Detection of different chemical moieties especially trace metals is important for humans as well as water safety. In this review, different detectors synthesized by the combination of different ligands with luminescent europium complexes were discussed for the separation of metals and chemical moieties in aqueous media. These detectors displayed high sensitivity and selectivity. The limit-of-detection values were very low indicating that these detectors are best suitable for the sensing of chemical moieties and trace metals. These detectors’ luminescent changes could be noticed with the naked eye.

Detection of organophosphorus pesticides by nanogold/mercaptomethamidophos multi-residue electrochemical biosensor

Based on the successful synthesis of mercaptomethamidophos as a substrate, a novel nanogold/mercaptomethamidophos multi-residue electrochemical biosensor was designed and fabricated by combining nanoscale effect, strong Au-S bonds as well as interaction between acetylcholinesterase (AChE) and mercaptomethamidophos, which can simultaneously detect 11 kinds of organophosphorus pesticides (OPPs) and total amount of OPPs using indirect competitive method. Electrochemical behavior of the modified electrode was characterized by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The AChE concentration and incubation time were optimized at 37.4 °C to achieve the best detection effect. This biosensor exhibits excellent electrochemical properties with a wider linear range of 0.1 ~ 1500 ng·mL^-1, lower detection limit of 0.019 ~ 0.077 ng·mL^-1, better stability and repeatability, which realizes the rapid detection of total amount of OPPs, and can simultaneously detect a large class of OPPs rather than one kind of OPP. Two OPPs (trichlorfon, dichlorvos) were detected in actual samples of apple and cabbage and achieved satisfactory test results.

Probing the potential of ureasil-poly(ethylene oxide) as a glyphosate scavenger in aqueous milieu: force-field parameterization and MD simulations

The intensive use of glyphosate in conventional agriculture and its high solubility in water have led to contamination of aqueous systems worldwide.