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1.
Food Chem ; 374: 131778, 2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-35021580

RESUMO

Core-shell structured magnetic covalent-organic frameworks (Fe3O4@TaTp) were facilely synthesized based on one-step functionalization at room temperature and applied for magnetic solid-phase extraction of okadaic acid from seawater and shellfish prior to LC-MS/MS detection. Parameters, including adsorbent amount, extraction time, desorption solution, and desorption time which could affect the extraction efficiency, were respectively investigated. The developed methods demonstrated good linearity (R2 > 0.99), acceptable accuracy and good precision (<15%), and low limit of detection (0.5 pg·mL-1 for seawater and 0.04 µg·kg-1 for shellfish). The amount of the material used (1 mg for seawater and 5 mg for shellfish) and the time required (4 min for seawater and 15 min for shellfish) for extracting analyte from 5 mL of seawater and 2 g of shellfish are both greatly shortened compared with the previous reports. In addition, we successfully applied this method to real sample analysis.


Assuntos
Estruturas Metalorgânicas , Adsorção , Cromatografia Líquida , Limite de Detecção , Fenômenos Magnéticos , Ácido Okadáico/análise , Água do Mar , Frutos do Mar/análise , Extração em Fase Sólida , Espectrometria de Massas em Tandem
2.
Anal Chim Acta ; 1191: 339293, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35033243

RESUMO

In this work, a new analytical approach based on ultrasound-assisted dispersive (micro)solid phase extraction (US-D-µSPE) using TpBD-Me2 covalent organic framework (COF) as adsorbent for simple, rapid and selective fluorescent determination of two polycyclic synthetic fragrances in seawater, i.e., 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-(γ)-2-benzopyran (HHCB), branded galaxolide®, and 7-acetyl-1,1,3,4,4,6-hexamethyltetralin (AHTN), branded tonalide®, is proposed. Different parameters involved in both adsorption and desorption steps were optimized in order to obtain the best results. High adsorption efficiencies in the range of 91.2-97.8% were achieved for both analytes. Desorption efficiencies of ∼98% for AHTN and HHCB were obtained using methanol as solvent, rendering the material recyclable with merely minor losses in adsorption efficiency after five consecutive cycles of adsorption/desorption. Limits of detection (LODs) were 0.082 µg L-1 and 0.070 µg L-1 for AHTN and HHCB, respectively. The proposed method was successfully applied for the analysis of seawater without the need for a previous sample treatment, e.g., pH adjustment. Recoveries in the range of 90.4-101.2% with a relative standard deviation of 5.8% were obtained for both fragrances. The results proved the great capacity of TpBD-Me2 COF for the selective sorption of polycyclic fragrances in combination with fluorescent detection, being highly promising for application to environmental monitoring of other emerging organic pollutants.


Assuntos
Estruturas Metalorgânicas , Perfumes , Poluentes Químicos da Água , Odorantes , Água do Mar , Extração em Fase Sólida , Poluentes Químicos da Água/análise
3.
Se Pu ; 40(1): 1-9, 2022 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-34985210

RESUMO

Norfloxacin (NFX) is an antibiotic that is widely used in animal husbandry. However, the presence of NFX even in trace amounts in animal-derived food may harm human health. Therefore, it is of practical significance to establish a method for monitoring NFX residues in food. Molecularly imprinted polymers (MIPs) imitate interactions established by natural receptors to selectively retain a target molecule, like antibodies or antigens do. MIPs have been widely employed in the selective recognition of specific target molecules from complex samples. Covalent organic frameworks (COFs) are a new type of organic polymer with uniform and ordered crystal structures. COFs form crystal structures by constructing organic units for ordered assembly through reversible chemical reactions. Their porous structure, regular morphology, and easy modification make COFs promising for use as excellent adsorbent carriers. Owing to these advantages of COFs, researchers have attempted to coat one MIP layer on COFs; however, the preparation methods are time-consuming and laborious, and the conditions are harsh. Hence, this study proposes a simple and rapid method for the preparation of novel MIPs with COFs as the support (DP-COF@MIPs) for the selective recognition of NFX. First, a Schiff-base COF (DP-COF) was rapidly synthesized using 3,3'-diaminobenzidine and p-phthalaldehyde with a metal trifluorate as a catalyst at room temperature. Subsequently, a two-step sequence was adopted as the synthesis strategy using NFX as the template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. The entire synthesis was completed within 5 h under mild conditions. The material was then characterized by multiple analytical methods, including field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and the Brunauer-Emmett-Teller (BET) method (to determine the specific surface area). The experimental results confirmed the successful preparation of DP-COF@MIPs. The DP-COF@MIPs presented a rough and porous surface, with a pore size of approximately 17.79 nm (mesoporous structure). The properties of the material were evaluated by adsorption and regeneration experiments. The kinetic adsorption experiment showed that the DP-COF@MIPs reached adsorption equilibrium in 90 min. Two straight lines were fitted using the pseudo-second-order kinetics model based on the experimental results for thermodynamic adsorption, indicating that the adsorption process was primarily dominated by chemical adsorption. The maximum apparent adsorption capacity was 41.57 mg/g. In the selective and competitive binding test, five drugs, namely ciprofloxacin, dimetridazole, oxytetracycline, sulfadiazine, and chloramphenicol, were selected as the interferents. The experimental results showed that the DP-COF@MIPs possessed good stereoselectivity and competitive recognition ability. The regeneration of DP-COF@MIPs was evaluated by multiple cycles of adsorption-desorption experiments. The loss in the adsorption capacity of the particles was only approximately 4.7% after seven adsorption-desorption cycles. These results from the regeneration experiments show that the DP-COF@MIPs had high stability and reusability in the selective adsorption and separation of NFX. In addition, the employed method could accurately identify trace NFX in milk samples. The average recoveries were in the range of 88.8%-92.9% at three spiked levels (0.03, 0.10, and 0.30 mg/L) with relative standard deviations (RSDs) in the range of 0.6-1.7% (n=3). Notably, the method could successfully determine NFX at contents as low as 0.0020 mg/L in the milk sample with an average recovery of 77.6% and RSD of 6.4% (n=3). This concentration is one-fiftieth of the maximum residue level stipulated by the European Union (EU), and even lower than the limit of detection (LOD) of conventional high performance liquid chromatography (HPLC) methods. The above results confirm that DP-COF@MIPs can be used to determine trace NFX in actual complex samples using HPLC equipment, even when coupled to conventional UV-Vis detectors. This study offers a facile and general method for the preparation of MIPs based on COFs with selective recognition ability.


Assuntos
Estruturas Metalorgânicas , Impressão Molecular , Adsorção , Animais , Humanos , Leite , Polímeros Molecularmente Impressos , Norfloxacino
4.
J Colloid Interface Sci ; 608(Pt 1): 1051-1063, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34785453

RESUMO

Organic semiconductors have been recognized as a new generation of photocatalysts for pollutants degradation and energy production. Herein, organic heterojunction (TpMa/CN) consisting of carbon nitride and ß-ketoenamine-based covalent organic framework is fabricated via a controllable self-assembly approach. The as-prepared TpMa/CN heterojunctions show enlarged visible-light absorption. The optimum TpMa/CN-5 photocatalyst achieves the highest photocatalytic activity towards tetracycline degradation, and its photocatalytic degradation rate is improved by 2.3 and 4.3 times than TpMa and CN, respectively. As a multifunctional photocatalyst, TpMa/CN-5 sample also shows remarkable photocatalytic activity for hydrogen peroxide production (880.494 µM h-1), which is 49 times higher than that of CN. Experimental and theoretical investigations indicate that a built-in electric field is formed at the interface of composite, which enables an accelerated charge transfer and separation. This work develops an effective strategy to design difunctional photocatalyst and deciphers the electronic properties and mechanisms of g-C3N4-based organic photocatalysts, which spurs further interests for organic heterojunction photocatalysts in the future.


Assuntos
Estruturas Metalorgânicas , Tetraciclina , Catálise , Luz , Semicondutores
5.
Talanta ; 238(Pt 2): 123030, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34801893

RESUMO

The development of analytical method for selective and sensitive detection of gossypol (Gsp), an extraction from the cotton plants, is important but still challenging in food safety and medical field. Herein, we reported a turn-on near infrared (NIR) fluorescence detection strategy for Gsp based on a metal-organic framework (MOF), QBA-Yb, which was prepared from 4,4'-(quinolone-5, 8-diyl) benzoate with Yb(NO3)3·5H2O by solvothermal synthesis. The Gsp acted as another "antenna" to sensitize the luminescence of Yb3+, leading to the turn-on NIR emission upon 467 nm excitation. As Gsp concentration increased, the NIR emission at 973 nm enhanced gradually, thus enabling highly sensitive Gsp detection in a turn-on way. The experiment and theoretical calculation results revealed the presence of strong hydrogen bonds between Gsp molecules and the MOF skeleton. The developed QBA-Yb probe showed excellent characteristics for detection of Gsp molecules, accompanied by wide linear range (5-160 µg/mL), low detection limit (0.65 µg/mL) and short response time (within 10 min). We have further demonstrated that the QBA-Yb probe was successfully applied for the determination of Gsp in real samples of cottonseeds.


Assuntos
Gossipol , Estruturas Metalorgânicas , Fluorescência , Luminescência
6.
Talanta ; 238(Pt 2): 123041, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34801898

RESUMO

A novel [Co(L)(H2O)2] (1) was obtained by hydrothermal method and it exhibited a 1D chain with exposed carboxyl groups, the unique coordination mode made it have unusual physical and chemical stability. Meanwhile, 1 showed peroxidase-like and weak oxidase-like activity. 1 as a peroxidase mimic enzyme had an excellent affinity for the substrates luminol and H2O2. Compared with HRP, 1 had catalytic activity in a wide pH range and showed the best catalytic activity at pH 7.4. Meanwhile, the catalysis process of 1 was reversible and recyclable, and the catalytic activity remained stable after different pH and temperatures and long-time storage. Based on the inhibition of glutathione on luminol-H2O2-MOF 1 chemiluminescence signal, a chemiluminescence method for the determination of glutathione has been proposed with high sensitivity and selectivity and had been applied for detecting glutathione in cell lysate with satisfactory results.


Assuntos
Estruturas Metalorgânicas , Catálise , Glutationa , Peróxido de Hidrogênio , Limite de Detecção , Luminescência , Medições Luminescentes , Luminol
7.
Talanta ; 238(Pt 2): 123047, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34801904

RESUMO

Lanthanide metal organic frameworks (L-MOFs) are emerging as promising electrochemiluminescence (ECL) emitters for bioanalysis. This work proposed a copper doped terbium MOF as a luminescent tag for construction of a "signal-on" ECL immunosensing method. The Tb-Cu-PA MOF was prepared using Tb3+ and Cu2+ ions as metal linkers and m-phthalic acid as bridge ligand, and exhibited strong ECL emission with K2S2O8 as a coreactant. The immunosensor was prepared by immobilizing capture antibody on Pd nanoparticles modified Ni-Co layered double hydroxide (Pd-ZIF-67@LDH) nanoboxes, which showed strong electrocatalytic activity toward the reduction of S2O82- for amplifying the ECL signal. Upon the sandwich-typed immunoreactions, Tb-Cu-PA MOF labeled antibody was introduced onto the immunosensor for sensitive ECL detection of target protein. Using cytokeratin 19 fragment 21-1 (CYFRA21-1), a representative lung cancer biomarker, as target model, the ECL immunosensing method showed a linear range of 0.01-100 ng/mL and a detection limit of 2.6 pg/mL (S/N = 3). This immunosensing strategy highlighted the advances of using luminescent and electroactive MOFs in the developments of highly efficient immunosensors for bioanalysis.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Estruturas Metalorgânicas , Antígenos de Neoplasias , Cobre , Técnicas Eletroquímicas , Imunoensaio , Queratina-19 , Limite de Detecção , Medições Luminescentes , Térbio
8.
Anal Chim Acta ; 1190: 339247, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34857146

RESUMO

Metal-organic frameworks (MOFs) can perform later transformation without compromising the integrity of the overall framework, and a variety of chemical reactions can be used to modify framework components. Postsynthetic modification (PSM) of MOFs has been developed as an alternative strategy that can expand the range of MOF functional groups. Considering the p-type semiconducting visible light active performance of CuBi2O4 (CBO) and the unique porous nanostructure and stability of zeolitic imidazolate framework-8 (ZIF-8), in this work, a novel core-shell coordination assembled hybrid based on p-type semiconductor@MOFs (Eu-CBO@ZIF-8) is prepared for the first time via in-situ growth and postsynthetic metal exchange. A series of detailed characterizations were conducted to confirm the successful synthesis of the material. Moreover, we are focusing on using this material as a new dual-functional sensing material for simultaneous detection and removal of tetracycline (TC), which shows an outstanding analytical performance with a low detection limit of 17 nM, relatively broad linear range (0-70 µM), fast response of less than 120 s, and excellent adsorption performance (377.07 mg g-1) toward TC. In addition, the sensitive luminescence response caused by TC makes Eu-CBO@ZIF-8 undergo a significant color transition from dark to red under UV-lamps, which is beneficial for visual analysis with the naked eye. The possible detection and adsorption mechanisms, including coordination between Eu3+ and the detected substance, the hydrogen bond between ligand and the detected substance, were further discussed. In addition, the practical feasibility of Eu-CBO@ZIF-8 for TC sensing was also studied, with a satisfactory recovery rate of 96.9%-104.6% and RSD ≤3.32%. These results indicate that this material can be used for the detection and adsorption of TC in actual samples.


Assuntos
Estruturas Metalorgânicas , Zeolitas , Adsorção , Antibacterianos , Tetraciclina
9.
J Colloid Interface Sci ; 607(Pt 2): 933-941, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34571314

RESUMO

A subtle flower-like MIL-125-NH2@BiOI was fabricated by a facile solvothermal method for simultaneously eliminating Cr(VI)/tetracycline mixed pollutants under visible light. The strong interaction between amino in MIL-125-NH2 and Bi3+ of BiOI promotes the formation of this unique inlaid structure and enables the favorable contact between MIL-125-NH2 and BiOI, thus accelerating the transfer of charge carriers. Remarkably, MIL-125-NH2@BiOI displays a superior activity compared with that of two monomers for the photocatalytic reduction of Cr(VI) and degradation of tetracycline. More significantly, the photocatalytic efficiency can be further boosted in the coexistence of Cr(VI) and tetracycline, which is 1.8 and 1.6 times that of single Cr(VI) and tetracycline, respectively. The synergistic effect between Cr(VI) reduction and tetracycline oxidative degradation can further facilitate the separation of photo-induced electrons and holes, resulting in the improved efficiencies in the Cr(VI)/tetracycline coexistent environment. This work sheds light on that MOF-based photocatalysts possess huge potential for practical environmental remediation.


Assuntos
Estruturas Metalorgânicas , Titânio , Catálise , Cromo , Tetraciclina
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 265: 120376, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34571376

RESUMO

Metal-organic framework (MOF) MOF-Fe nanosols were prepared, which exhibits strongly catalysis of the new fluorescence indicator reaction of 3, 3', 5, 5'-tetramethylbenzidine (TMB)-H2O2 to produce the oxidation product TMBOX. The TMBOX fluorescent probe has a strong fluorescence peak at 405 nm. After optimizing the various conditions for the determination of H2O2 system and glucose system, the linear range of fluorescence determination of H2O2 was 0.75-7.5 µM, and the detection limit was 0.3 µM. Since H2O2 is the product of glucose oxidase (GOD) catalyzed oxidation of glucose, and a simple and convenient fluorescence method was also established for glucose. The results show that the glucose concentration in the range of 0.2-20 µM has a good correlation with the fluorescence intensity, and the detection limit of glucose was 0.1 µM. This method has been used to detect the content of glucose in drinks with satisfactory results.


Assuntos
Peróxido de Hidrogênio , Estruturas Metalorgânicas , Catálise , Colorimetria , Glucose , Glucose Oxidase/metabolismo , Limite de Detecção , Oxirredução
11.
J Colloid Interface Sci ; 607(Pt 2): 1382-1390, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34583043

RESUMO

Metal organic frameworks (MOFs) with physicochemical properties and adjustable structures have been proposed as very attractive materials. The studies on development of such functional materials tended to fabricate featured MOF objects with fascinating catalytic capabilities to utilize their biomedical values. In this paper, we present novel biocompatible manganese metal organic framework (Mn-MOF)-based catalase mimetics with microfluidic microcapsule encapsulation for intravital inflammatory bowel disease (IBD) treatment. Phosphoserine, a component of the cell membrane, served as an organic ligand to ensure biocompatibility of Mn-MOF. Owing to the core-shell structure of the microcapsule, the Mn-MOF exhibited a well-organized distribution and controlled release features, which could protect them from gastric juice and provide function in the intestine. Upon reaching the sites of the inflammatory bowel, Mn-MOF could effectively scavenge reactive oxygen species (ROS) over-produced by neutrophils and macrophages under various gastrointestinal pH environments, protecting intestinal epithelial cells from ROS damage. The Mn-MOF-encapsulated microcapsules exhibited high performances in treating spontaneous IBD in interleukin-10-deficient mice by relieving the oxidative stress, reducing the inflammation, and restoring the intestinal barrier. These results indicate that the functional Mn-MOF-encapsulated microcapsules have practical applications in the treatment of ROS-associated diseases.


Assuntos
Doenças Inflamatórias Intestinais , Estruturas Metalorgânicas , Animais , Doenças Inflamatórias Intestinais/tratamento farmacológico , Íons , Manganês , Camundongos , Microfluídica
12.
J Colloid Interface Sci ; 607(Pt 2): 1651-1660, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34592552

RESUMO

The rational integration of chemotherapy and hydroxyl radical (·OH)-mediated chemodynamic therapy (CDT) via functional metal-organic frameworks (MOF) carriers has great potential in cancer therapy. In this work, aminotriazole (3-AT) doped polyhedral metal organic frameworks (denoted as MAF) were prepared by template ligand replacement, where CDT was initiated by Cu2+/Cu+ modulated Fenton reaction and enhanced by effectively regulating the catalase activity with 3-AT. However, a rod-like Cu-MOF with 3-AT served as a ligand was obtained by the hydrothermal method without using template. In contrast to Cu-MOF, pH-responsive MAF was chosen as the carrier for targeted drug delivery due to its higher drug load of 17.6% and relatively uniform size, where doxorubicin (DOX) as a model drug was loaded in its cavity and hyaluronic acid (HA) was coated on its surface via electrostatic interactions (denoted as HA-MAF@DOX). In vitro experiments demonstrated that HA-MAF@DOX had high transport efficiency of DOX, effective regulation of catalase (CAT) activity and enhanced cytotoxicity to HepG2 cells. This work is the first use of enzyme inhibitors as ligands to construct functional MOFs via template ligand replacement for effective regulating enzyme activity, mediating intracellular redox homeostasis and enhancing CDT efficacy, which provides a feasible strategy for the construction the functional MOFs in cancer therapy.


Assuntos
Estruturas Metalorgânicas , Amitrol (Herbicida) , Catalase , Peróxido de Hidrogênio , Concentração de Íons de Hidrogênio , Espécies Reativas de Oxigênio
13.
J Colloid Interface Sci ; 607(Pt 2): 1762-1775, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34600340

RESUMO

Excess fluoride in water poses a threat to ecology and human health, which has attracted global attention. In this study, a series of lanthanum-based metal-organic frameworks (La-MOFs) were synthesized by varying the organic ligands (i.e., terephthalic acid (BDC), trimesic acid (BTC), biphenyl-4,4-dicarboxylic acid (BPDC), 2,5-dihydroxyterephthalic acid (BHTA), and 1,2,4,5-benzenetetracarboxylic acid (PMA)) to control the microscopic structure of the MOFs and subsequently apply them for the removal of fluoride in water. The maximum capture capacities of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC at 298 K are 105.2, 125.9, 145.5, 158.9, and 171.7 mg g-1, respectively. The adsorption capacity is greater than most reported adsorbents. The adsorption isotherms of La-MOFs for fluoride are well fit to the Langmuir isotherm model. In addition, the adsorption kinetics of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC follows the pseudo-second-order kinetic model, and the kinetic rate-limiting step of adsorption is chemical adsorption. Thermodynamics revealed that temperature is favorable for the adsorption of fluoride. Meanwhile, La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC are suitable for the removal of fluoride in a relatively wide pH range (4.0-9.0). Simultaneously, from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis, electrostatic attraction and ligand exchange are identified as the main action mechanisms for the adsorption of fluoride of La-MOFs. The prepared La-MOFs are used as efficient adsorbents for removal of fluoride in actual water, indicating that they have great potential in removing fluoride in real and complex environmental water. This work provides a new strategy for designing adsorbents with adjustable microstructure and expected function to effectively recover fluorosis in water.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Fluoretos , Humanos , Concentração de Íons de Hidrogênio , Cinética , Lantânio , Ligantes , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Poluentes Químicos da Água/análise
14.
Food Chem ; 371: 131145, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34600366

RESUMO

Zearalenone (ZEN) poses a serious threat to human and animal health. The development of sensitive determination methods for ZEN is of great significance for ensuring the quality and safety of food. Herein, based on a stimuli-responsive aptamer-functionalized metal-organic framework (MOF) nano-container and trivalent DNA peroxidase mimicking enzyme (DNAzyme), an efficient aptasensor was constructed initially for the colorimetric determination of ZEN. The proposed aptasensor only required simple operations but exhibited outstanding specificity, reproducibility, storage stability and reusability simultaneously. Under the optimal conditions, there was a good linear relationship between the changed absorbance and logarithm concentration of ZEN within 0.01-100 ng mL-1, and the limit of detection (LOD) could reach 0.36 pg mL-1. Moreover, the proposed aptasensor was reliable in quantifying ZEN in spiked food samples. The current bioassay provides a promising scheme for constructing stable, specific and rapid colorimetric platforms with potential applications in the fields of food safety.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , DNA Catalítico , Estruturas Metalorgânicas , Zearalenona , Colorimetria , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Zearalenona/análise
15.
Food Chem ; 372: 131208, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34601418

RESUMO

A simple, environmentally-friendly and reliable method was developed to simultaneously monitor the residue of methyl 1-naphthalene acetate, parathion-methyl, fenitrothion, bromophos and phenthoate in pomelo by using dispersive solid-phase extraction technique (d-SPE). In this method, these target analytes were captured by MIL-125-NH2 and detected by GC-MS/MS. The key parameters of d-SPE were optimized by the single factor experiment. Under the optimized conditions, a good determination coefficient (R2 > 0.9922) and extraction recoveries (64.7-116.8%) are obtained. The limit of detections (0.03-1.07 ng/g) is lower than the MRLs in citrus fruits established by EU (10-15000 ng/g) and China (10-10000 ng/g). The precisions of intra-day and inter-day are 1.3-8.9% and 3.8-14.9%, respectively. In addition, the sorbent MIL-125-NH2 is stable and can be reused at least eight times. These results prove the established method is efficient and reliable to detect the pesticide residues in pomelo.


Assuntos
Estruturas Metalorgânicas , Resíduos de Praguicidas , Frutas/química , Dietilamida do Ácido Lisérgico/análogos & derivados , Resíduos de Praguicidas/análise , Extração em Fase Sólida , Espectrometria de Massas em Tandem
16.
Talanta ; 236: 122822, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635212

RESUMO

A novel label-free and enzyme-free detection strategy has been developed for the electrochemical biosensor detection of isocarbophos (ICP) using UiO-66-NH2 and aptamer as the signal transducers. In this work, the ICP aptamers were attached to UiO-66-NH2 through physical mixing and chemical combination methods. In the presence of ICP, the aptamers could undergo conformational change and bind to them, which prevent the electron transfer to the surface of electrode. By comparing the two conjunction approaches of aptasensors, these proposed strategies could selectively and sensitively detect ICP with a detection limit of 6 ng mL-1 (20.74 nM) and 0.9 ng mL-1 (3.11 nM). Furthermore, we have also demonstrated the capability of this strategy in the detection of ICP in real samples from vegetable and fruit extract, indicating the potential application of this strategy in food safety issues.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Estruturas Metalorgânicas , Malation/análogos & derivados , Zircônio
17.
Talanta ; 236: 122829, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635219

RESUMO

The successful application of covalent organic frameworks (COFs) depends on not only their unique chemical structures but also their morphology, size, and architecture. Spherical COFs (SCOFs) are attracted special attention due to the superiority of spherical materials in many applications. However, the synthesis of uniform large-sized SCOFs remains a challenge. Herein, by carefully optimizing the synthesis of a heteropore COF, we find that solvent type and catalyst concentration play important roles in determining the morphology and size of COFs, and eventually achieve the controllable synthesis of large SCOFs with uniform sizes ranging from 200 µm to 5 mm. The obtained SCOFs keep the dual-pore feature of the heteropore COF and show good stability and high crystallinity. To exhibit the superior application potential of SCOFs, the SCOFs with a size range of 200-300 µm were demonstrated to be promising solid-phase extraction (SPE) fillers. As-prepared SCOFs-packed SPE column could effectively remove ≥99% phytochrome matrix from 6 different vegetable samples in 10 s, accompanied by 72.56-112.37% recoveries of 33 chemical hazards with different physicochemical properties, thus showing greatly promising application prospects in sample pretreatment of nontargeted food safety analysis. By utilizing acid/base-adjusted reversible color change, millimeter-sized SCOFs were developed as an easy-to-operate and reusable naked-eye indicator of acids.


Assuntos
Estruturas Metalorgânicas , Catálise , Extração em Fase Sólida , Verduras
18.
Talanta ; 236: 122831, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635221

RESUMO

In this study, a novel type of covalent organic framework (COF) material rich in boronic acid sites was prepared through post-synthesis modification (TbBD@PEI@Au@4-MPBA). The surface of COF material had abundant carboxylic acid groups, which could bind a large amount of polyethyleneimine (PEI) through electrostatic interaction. At the same time, the amino groups on the PEI can be grafted with Au nanoparticles (Au NPs) in situ, and then 4-mercaptophenylboronic acid (4-MPBA) was modified by the reaction of Au and sulfhydryl groups. The massive grafting of boronic acid groups made the material's enrichment effect on glycopeptides expected. The results of experiments indicated that the composite material has high sensitivity (5 amol µL-1) and selectivity (1:1000). In addition, the material has outstanding stability and reusability, with a load capacity of about 100 mg g-1 and a recovery of 99.3 ± 2.2%. What's more, after enriched by TbBD@PEI@Au@4-MPBA, 56 endogenous glycopeptides from fresh human saliva were detected by MALDI-TOF MS, 56 unique glycopeptides corresponding to 31 glycoproteins from human saliva and 513 unique glycopeptides corresponding to 208 glycoproteins from serum of throat cancer patient were detected by nano-LC-MS/MS, respectively, which was expected to be applied to glycoproteomics research.


Assuntos
Nanopartículas Metálicas , Estruturas Metalorgânicas , Glicopeptídeos , Ouro , Humanos , Interações Hidrofóbicas e Hidrofílicas , Saliva , Espectrometria de Massas em Tandem
19.
Talanta ; 236: 122859, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635243

RESUMO

The sensitivity and selectivity of electrochemical analysis are challenging due to the materials used for electrode modification as well as electrical conductivity, catalytic activity and recognition ability of the working electrode. In this work, a portable 3D-printed electrochemical electrode clamp was designed and applied in combination with the developed covalent organic framework (COF DQTP)-modified pencil graphite electrode (DQTP/PGE). The ß-ketoenamine-linked COF DQTP synthesized by 1,3,5-triformylphloroglucinol (TP) and 2,6-diaminoanthraquinone (DQ) through solvothermal method is a porous crystalline with excellent conductivity and large periodic π-arrays, coupled with commercial available pencil graphite electrode to fabricate a disposable sensor for simultaneous determination of environmental endocrine disruptors bisphenol A and bisphenol S. The DQTP/PGE sensor exhibited high electrical conductivity and catalytic activity, and a good linearity was obtained in a range of 0.5-30 µM for two bisphenols with a detection limit of 0.15 µM (S/N = 3). Moreover, the sensor showed a reproducible and stable response over one month with negligible interference, and an accepted recovery with real food packaging samples.


Assuntos
Grafite , Estruturas Metalorgânicas , Compostos Benzidrílicos , Eletrodos , Fenóis , Sulfonas
20.
Talanta ; 236: 122877, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635257

RESUMO

A covalent organic framework (named as TpDq) linked by ß-ketoamine was prepared by imine condensation reaction with 1,3,5-triformylphloroglucinol (TFP) and 2,6-diaminoanthraquinone (DAAQ) as building blocks. Via employing a functionalized modification strategy, a new lanthanide complex Eu3+-ß-diketone functionalized covalent organic framework hybrid material, Eu-TTA@TpDq (TTA = 2-thenoyltrifluoroacetone), has been synthesized. After post-synthetic modification (PSM), the shape and structure of the parent framework is well preserved and the modified material shows remarkable luminescence properties. Based on this, we designed it as a fluorescent probe and tried to use it to sense common aldehydes. The results indicate that Eu-TTA@TpDq exhibits a turn-off response toward glutaraldehyde which can distinguish from other common aldehydes. The fluorescent probe has the advantages of reusability, pH stability (4.50-8.52), fast luminescence response (<1 min) and low detection limit. The linear range of this method was 0-100 µM; the detection limit was 4.55 µM; the relative standard deviation was 2.16%. Furthermore, it has broad application prospect in both practical sensing of glutaraldehyde in water environment and simple detection of glutaraldehyde vapor. In addition, we preliminarily discussed the possible sensing mechanism.


Assuntos
Elementos da Série dos Lantanídeos , Estruturas Metalorgânicas , Glutaral , Cetonas , Luminescência
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