In situ self-assembled cationic lanthanide metal organic framework membrane sensor for effective MnO4- and ascorbic acid detection

A high-performance photoelectrochemical sensor based on CdS-Au composite nanomaterials and localized surface plasmon resonance for ultrasensitive detection of ascorbic acid

Ascorbic acid (AA), which plays a vital role in the metabolism of the human body, is closely correlated with various diseases, including rheumatoid arthritis, scurvy, Parkinson's disease, urinary stones, and diarrhea. The detection of AA is of great significance for early prevention and diagnosis of related diseases. In this paper, a high-performance photoelectrochemical (PEC) sensor was constructed based on cadmium sulfide-gold (CdS-Au) composite nanomaterials for ultrasensitive ascorbic acid (AA) detection. Due to the localized surface plasmon resonance (LSPR) effect of gold nanoparticles (AuNPs), the PEC performance of CdS-Au composite nanomaterials was significantly improved compared to CdS semiconductor nanomaterials. Under the optimal conditions, the AA concentration was linearly related to the photocurrent signal in the range of 0.01 μM-200 μM, with the detection limit being 0.2 nM (S/N = 3) and the sensitivity being 642.9 μA mM-1 cm-2. In addition, the mechanism of the PEC sensor based on CdS-Au composite nanomaterials for ultrasensitive AA detection was discussed. Lastly, the self-constructed PEC sensors have been successfully applied in detecting AA in vitamin C tablets and actual blood samples, meeting the detection criteria required by the Chinese Pharmacopoeia (CP, 2020 edition). The self-fabricated PEC sensors in this paper are expected to be used for quality assessment of AA-related drugs and diagnosis of relevant diseases.

Orange peel-derived carbon dots/Cu-MOF nanohybrid for fluorescence determination of l-ascorbic acid and Fe3. Anal Chim Acta 2024;1287:342066. [PMID: 38182373 DOI: 10.1016/j.aca.2023.342066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Recycling and reuse of biomass waste in synthesis of nanomaterials have recently received much attention as an effective solution for environmental protection and sustainable development. Herein, nitrogen-doped carbon dots (N-CDs) with blue emission were synthesized from the orange peels as a precursor through a simple hydrothermal method and then, modified with ethylenediamine tetraacetic acid (N-CD@EDTA). The N-CD@EDTA was embedded as a fluorophore in Cu-based metal-organic framework (MOF-199) structure (N-CD@EDTA/MOF-199) to construct fluorescence sensor toward l-ascorbic acid (L-AA) determination. The N-CD@EDTA/MOF-199 nanohybrid significantly and selectively turned on toward L-AA determination during the fluorimetric experiments. Under optimal conditions, the probe showed a suitable linear response in the concentration range of 10 nM-100 μM with a low limit of detection (LOD) of 8.6 nM and high sensitivity of 0.201 μM-1. The possible mechanism of recognition and adsorption, including the reduction of Cu 2+ nodes in the MOF-199 structure in the presence of L-AA and the release of trapped N-CD@EDTA into the solution, was explored. Moreover, the N-CD@EDTA/MOF-199/L-AA (100 μM) system was further applied as a fluorescent "on-off" sensor for Fe3+ determination with a LOD of 1.15 μM. The proposed probe was successfully used in orange juice and water samples to determine L-AA and Fe3+ with satisfactory recovery, which displays the promising capability of sensor in real samples. The recoveries obtained by suggested method are consistent with that obtained from high performance liquid chromatography (HPLC) and atomic absorption spectroscopy which confirm the favorable characteristic of the sensor for accurate determination of L-AA and Fe3+ in practical applications.

Metal-organic frameworks (MOFs) based luminescent and electrochemical sensors for food contaminant detection

With the increasing population, food toxicity has become a prevalent concern due to the growing contaminants of food products. Therefore, the need for new materials for toxicant detection and food quality monitoring will always be in demand. Metal-organic frameworks (MOFs) based on luminescence and electrochemical sensors with tunable porosity and active surface area are promising materials for food contaminants monitoring. This review summarizes and studies the most recent progress on MOF sensors for detecting food contaminants such as pesticides, antibiotics, toxins, biomolecules, and ionic species. First, with the introduction of MOFs, food contaminants and materials for toxicants detection are discussed. Then the insights into the MOFs as emerging materials for sensing applications with luminescent and electrochemical properties, signal changes, and sensing mechanisms are discussed. Next, recent advances in luminescent and electrochemical MOFs food sensors and their sensitivity, selectivity, and capacities for common food toxicants are summarized. Further, the challenges and outlooks are discussed for providing a new pathway for MOF food contaminant detection tools. Overall, a timely source of information on advanced MOF materials provides materials for next-generation food sensors.

Multiple Interpenetrating Metal-Organic Frameworks with Channel-Size-Dependent Behavior for Selective Gossypol Detection and Perovskite Quantum Dot Encapsulation

An interpenetrating structure endows metal-organic frameworks (MOFs) with many exciting applications, such as fluorescence detection and host-guest chemistry. Herein, two unique structure-interpenetrating In-MOFs (In-pdda-1 and In-pdda-2; H2pdda = 4,4'-(pyridine-2,5-diyl)dibenzoic acid) are constructed by different coordination configurations. The four-connected In3+ center shows a triangular-pyramidal configuration or a 2D rectangle, forming an unc topology for In-pdda-1 and a sql network for In-pdda-2, respectively. Two different interpenetrating modes created by linear rigid ligands and metal clusters are observed in the two MOFs (In-pdda-1, 8-fold interpenetrating mode; In-pdda-2, [2D + 2D] interpenetrating mode), which determine the channel-size-dependent properties in fluorescence applications. During the quantitative detection process of gossypol, the small rhombic channels divided by interpenetrating molecular planes of In-pdda-2 greatly limit the distance between the analyte and the probe, promoting electron transfer and energy transfer processes and thus resulting in a low detection limit (28.6 nM). In addition, the pore size effect of In-pdda-1 encouraged us to explore an in situ perovskite quantum dot encapsulation strategy to obtain a MAPbBr3@MOF material with tunable and stable luminescence properties. Both of the above channel-size-dependent fluorescence properties may provide inspiration for the structural design and specialized applications of MOF materials.

Amino-Functionalized Perylenediimide Derivative with Dual Fluorescence Emission for the Detection of Ascorbic Acid in Vivo and Vitro

The rapid, sensitive, and selective detection of ascorbic acid (AA) is of significance in medical assays and diagnostics. In this work, a new amino perylenediimide derived (APDI) ratiometric fluorescent probe based on the specific redox reaction of cobalt oxyhydroxide (CoOOH) and AA was constructed. APDI exhibited dual fluorescence emission peaks at 549 and 596 nm with an excitation wavelength of 494 nm. In the presence of CoOOH, the dual fluorescence could be quenched. The dominant fluorescence quenching mechanism was caused by the inner filter effect. Using the red emission as a reference, the fluorescence intensity ratio (F₅₄₉ /F₅₉₆ ) was linearly correlated with the concentration of AA over a range of 0.05 to 1 μM. The limit of detection for AA was found to be 17 nM. Importantly, the probe was successfully used to detect AA in living cells. Therefore, this high sensitivity and selectivity strategy could directly survey the AA levels in real samples.

A minimalist fluorescent MOF sensor array for Baijiu identification

The beverage industry is in the market tuyere, and grasps the lifeline of the social economy, so it is particularly vital to supervise it. Herein, we report a minimalist fluorescence metal-organic framework (MOF) sensor array for Baijiu identification. The original MOF was modified by rare-earth elements to obtain Eu-MOFs and Tb-MOFs. They exhibited multiple fluorescence characteristic peaks in the range of 400-700 nm when excited at 325 nm. The organic molecules in the Baijiu reacted with Eu-MOF and Tb-MOF, affecting the energy transfer of the entire system and the electronic transition of Eu³⁺ and Tb³⁺, which were accompanied by various changes in the fluorescence intensity. For each analyte, a unique fluorescence fingerprint and heat map would be formed, which could be discriminated by pattern recognition. With this method, 11 kinds of organic molecules were identified accurately. A good stepwise bilinear function between the fluorescence intensity and concentrations of ferulic acid was obtained at 0.2-3.13 μM and 6.25-100 μM. Crucially, 16 kinds of Baijius of different brands were accurately identified with an accuracy of 100%. The sensor array showed the advantages of strong maneuverability and fast response, exhibiting good application value in Baijiu detection.

A dual-function Cd-MOF with high proton conduction and excellent fluorescence detection of pyridine

Metal-organic frameworks have great potential in the field of proton conducting materials and fluorescent probes due to their structural tunability and designability. A novel water-stable metal organic framework material [Cd₂(Hdpb)(H₂O)₃] (Cd-MOF) was synthesized based on H₅dpb (H₅dpb = 3,5-diphosphonobenzoic acid) and Cd²⁺ ions. Cd²⁺ ions are connected with phosphonates and carboxyl groups of H₅dpb to form an infinitely extended 1D chain, which is further connected by the Hdpb^4- ligand and coordinated water to form a three-dimensional network structure. There are hydrogen bond networks in the 3D structure of the Cd-MOF, which are favorable for proton transfer, achieving its maximum proton conductivity of 2.97 × 10^-3 S cm^-1 at 338 K and 98% relative humidity (RH). To realize its application in fuel cells, the Cd-MOF was introduced into the chitosan (CS) matrix, and a series of composite membranes (Cd-MOF@CS-X) with high proton conductivity were obtained. The results of AC impedance show that the proton conductivity of Cd-MOF@CS-5 reaches 3.55 × 10^-1 S cm^-1 at 358 K and 98% RH, which is comparable to the highest values reported for MOF-polymer complexes. Moreover, the Cd-MOF can be used as a selective fluorescent probe for pyridine detection, and its detection limit can reach 1.0 × 10^-6 M. A bifunctional MOF with proton conduction and pyridine recognition is reported for the first time, and has important reference value for the practical application of functional MOFs in both electrochemical and luminescence sensing.

Fast Detection of Entacapone by a Lanthanide-Organic Framework with Rhombic Channels

Entacapone (ENT) is a powerful catechol-O-methyl transferase inhibitor that is used for the diagnosis and treatment of Parkinson's syndrome, but the amount used must be well controlled to avoid overtreatment and side effect. Fast and selective detection of ENT needs well-matched energy levels and well-designed sensor-ENT interaction which is highly challenging. In this work, a water stable europium-based metal-organic framework (Eu-TDA) was synthesized to detect ENT by luminescence with excellent reusability and selectivity in the presence of main coexisting and interference species of plasma with a limit of detection of 5.01 μM. The experimental results showed that the luminescence of Eu-TDA can be effectively quenched by ENT via well-designed photoinduced electron transfer mechanism and internal filtration effect mechanism in the system.

Stimuli-Responsive Metal-Organic Framework on a Metal-Organic Framework Heterostructure for Efficient Antibiotic Detection and Anticounterfeiting

Stimuli-responsiveness is an important characteristic that show promising potential in various applications. Herein, a novel ZIF-8-on-Tb-dpn (H₃dpn = 5-(2',4'-dicarboxylphenyl)nicotic acid) heterostructure is constructed using a heteroepitaxial strategy combining the chemical-responsive (antibiotics) and light-responsive behaviors. The pyridine nitrogen of Tb-dpn acts as an anchor site for Zn²⁺, which helps to overcome the limit of lattice mismatch between two metal-organic frameworks (MOFs) and promotes the growth of ZIF-8 nanocrystals. Based on the synergy effect of two MOFs, ZIF-8-on-Tb-dpn exhibits an efficient turn-off response toward tetracycline and chloramphenicol via competitive absorption, Förster resonance energy transfer, and photoinduced electron transfer processes with limit of detection values of 5.6 and 37.6 nM, respectively, which are three- to -fivefold lower than those of Tb-dpn. Moreover, the nanocage of ZIF-8 is utilized to encapsulate photochromic spiropyran (SP) molecules and realize the reversible conversion between SP and merocyanine (MC) under visible light and ultraviolet light. The MC form is accompanied with strong adsorption at 555 nm, which can erase the emission of Tb³⁺. Therefore, a reversible invisible anticounterfeiting pattern is designed with SP ⊂ ZIF-8-on-Tb-dpn for information anticounterfeiting. The excellent stimuli-responsive ability makes the luminescent platform a potential candidate in luminescence applications.

An electrostatic repulsion strategy for a highly selective and sensitive “switch-on” fluorescence sensor of ascorbic acid based on the cysteamine-coated CdTe quantum dots and cerium(iv)

A highly selective “switch-on” fluorescence approach for sensing of ascorbic acid (AA) based on the system of CA-CdTe QDs-Ce⁴⁺-AA was developed.