Trinitromethyl-Substituted 1H-1,2,4-Triazole Bridging Nitropyrazole: A Strategy of Utterly Manipulable Nitration Achieving High-Energy Density Material.

Nitro groups have been demonstrated to play a decisive role in the development of the most powerful known energetic materials. Two trinitromethyl-substituted 1H-1,2,4-triazole bridging nitropyrazoles were first synthesized by straightforward routes and were characterized by chemical (MS, NMR, IR spectroscopy, and single-crystal X-ray diffraction) and experimental analysis (sensitivity toward friction, impact, and differential scanning calorimetry-thermogravimetric analysis test). Their detonation properties (detonation pressure, detonation velocity, etc.) were predicted by the EXPLO5 package based on the crystal density and calculated heat of formation with Gaussian 09. These new trinitromethyl triazoles were found to show suitable sensitivities, high density, and highly positive heat of formation. The combination of exceedingly high performances superior to those of HMX (1,3,5,7-tetranitrotetraazacyclooctane), and its straightforward preparation highlights compound 8 as a promising high-energy density material (HEDM). This work supports the effectivity of utterly manipulable nitration and provides a generalizable design synthesis strategy for developing new HEDMs.

Synthesis and detonation characters of 3,4,5-1H-trinitropyrazole and its nitrogen-rich energetic salts.

The development of energetic materials is still facing challenges due to the inherent contradiction between energy and sensitivity. Two new nitrogen-rich energetic salts of 3,4,5-1H-trinitropyrazole (HTNP) were synthesized. They are fully characterized by X-ray diffraction, NMR, MS and IR spectroscopy. The DSC and BAM tests were carried out as well. These TNP salts show high thermostability and high positive heat of formation. Their detonation performances were calculated by the EXPLO5 program. Most noteworthy is that DATr salt exhibits superior sensitivity and detonation performance comparable to secondary explosive RDX, making it promising for use as a new-generation green energetic material.

Glucan Synthase-like 2 is Required for Seed Initiation and Filling as Well as Pollen Fertility in Rice.

BACKGROUND: The Glucan synthase-like (GSL) genes are indispensable for some important highly-specialized developmental and cellular processes involving callose synthesis and deposition in plants. At present, the best-characterized reproductive functions of GSL genes are those for pollen formation and ovary expansion, but their role in seed initiation remains unknown. RESULTS: We identified a rice seed mutant, watery seed 1-1 (ws1-1), which contained a mutation in the OsGSL2 gene. The mutant produced seeds lacking embryo and endosperm but filled with transparent and sucrose-rich liquid. In a ws1-1 spikelet, the ovule development was normal, but the microsporogenesis and male gametophyte development were compromised, resulting in the reduction of fertile pollen. After fertilization, while the seed coat normally developed, the embryo failed to differentiate normally. In addition, the divided endosperm-free nuclei did not migrate to the periphery of the embryo sac but aggregated so that their proliferation and cellularization were arrested. Moreover, the degeneration of nucellus cells was delayed in ws1-1. OsGSL2 is highly expressed in reproductive organs and developing seeds. Disrupting OsGSL2 reduced callose deposition on the outer walls of the microspores and impaired the formation of the annular callose sheath in developing caryopsis, leading to pollen defect and seed abortion. CONCLUSIONS: Our findings revealed that OsGSL2 is essential for rice fertility and is required for embryo differentiation and endosperm-free nucleus positioning, indicating a distinct role of OsGSL2, a callose synthase gene, in seed initiation, which provides new insight into the regulation of seed development in cereals.

Enhanced performance of ZIF-8 nanocrystals hybrid monolithic composites via an in-situ growth strategy for efficient capillary microextraction of perfluoroalkyl phosphonic acids.

Enrichment of perfluoroalkyl phosphonic acids (PFPAs) is of great significance and challenging for environmental monitoring, due to their toxic and persistent nature, highly fluorinated character as well as low concentration. Herein, novel metal-organic frameworks (MOFs) hybrid monolithic composites were prepared via metal oxide-mediated in situ growth strategy and utilized for capillary microextraction (CME) of PFPAs. A porous pristine monolith was initially obtained by copolymerization of the zinc oxide nanoparticles (ZnO-NPs)-dispersed methacrylic acid (MAA) with ethylenedimethacrylate (EDMA) and dodecafluoroheptyl acrylate (DFA). Afterwards, nanoscale-facilitated transformation of ZnO nanocrystals into the zeolitic imidazolate framework-8 (ZIF-8) nanocrystals was successfully realized via the dissolution-precipitation of the embedded ZnO-NPs in the precursor monolith in the presence of 2-methylimidazole. Experimental and spectroscopic results (SEM, N2 adsorption-desorption, FT-IR, XPS) revealed that the coating of ZIF-8 nanocrystals significantly increased the surface area of the obtained ZIF-8 hybrid monolith and endowed the material abundant surface-localized unsaturated zinc sites. The proposed adsorbent showed highly enhanced extraction performance for PFPAs in CME, which was mainly ascribed to the strong fluorine affinity, Lewis acid/base complexing, anion-exchange, and weakly π-CF interaction. The coupling of CME with LC-MS enables effective and sensitive analysis of ultra-trace PFPAs in environment water and human serum. The coupling method demonstrated low detection limits (2.16-4.12 ng L-1) with satisfactory recoveries (82.0-108.0%) and precision (RSDs ≤6.2%). This work offered a versatile route to design and fabricate selective materials for emerging contaminant enrichment in complicated matrices.

Ionic liquid assisted in situ growth of nano-confined ionic liquids/metal-organic frameworks nanocomposites for monolithic capillary microextraction of microcystins in environmental waters.

A facile in-situ ionothermal synthesis strategy for fabrication of ionic liquids/metal-organic frameworks (MOFs) (ILs@ZIF-8) nanocomposites hybrid monolith has been proposed to facilitate highly effective capillary microextraction (CME) of ultra-trace microcystins (MCs) in environmental waters. The ZnO nanoparticles (ZnO-NPs) were initially introduced into a precursor polymer monolith, and acted as the metal sources and anchoring seeds to construct ILs@ZIF-8 nanocomposites hybrid monolith via a nanoparticle-directed in-situ growth route in confined imidazolium ionic liquids. Detailed characterization based on scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2 adsorption-desorption isotherms confirmed that both the morphology and porous structure of ZIF-8 were finely tuned by the incorporation of ILs, which acted as solvents and structure directing agent. The confinement of ILs in ZIF-8 framework endows the ILs@ZIF-8 hybrid monolith additional adsorption sites and satisfied water stability for the synergistic enhancement of adsorption efficiency of MCs via multiple interactions (including π-π stacking, hydrogen bonding, hydrophobic and electrostatic interactions). Coupling ILs@ZIF-8 hybrid monolith-based CME to LC-MS enabled an efficient and sensitive analysis of MCs in surface waters with ultra-low detection limits (LOD ≤ 1.4 ng L-1) and satisfactory recoveries (70.2%-107.0%). This study showed great potential for feasible design and fabrication of ILs@MOFs composites with synergistic and tunable structures toward efficient sample preparation applications.

Thermo-Sensitive Spikelet Defects 1 acclimatizes rice spikelet initiation and development to high temperature.

Crop reproductive development is vulnerable to heat stress, and the genetic modulation of thermotolerance during the reproductive phase, especially the early stage, remains poorly understood. We isolated a Poaceae-specific FAR-RED ELONGATED HYPOCOTYLS3 (FHY3)/FAR-RED IMPAIRED RESPONSE1 (FAR1)family transcription factor, Thermo-sensitive Spikelet Defects 1 (TSD1), derived from transposase in rice (Oryza sativa) TSD1 was highly expressed in spikelets, induced by heat, and specifically enhanced the thermotolerance of spikelet morphogenesis. Disrupting TSD1 did not affect vegetative growth but markedly retarded spikelet initiation and development, as well as caused varying degrees of spikelet degeneration, depending on the temperature. Most tsd1 spikelets were normal at low temperature but gradually degenerated as temperature increased, and all disappeared at high temperature, leading to naked branches. TSD1 directly promoted the transcription of YABBY1 and YABBY3 and could physically interact with YABBY1 and three TOB proteins, YABBY5, YABBY4, and YABBY3. These YABBY proteins can form either homodimers or heterodimers and play an important role in spikelet morphogenesis, similar to TSD1. Notably, the knockout mutant yab5-ko and double mutant tsd1 yab5-ko resembled tsd1 in spikelet appearance and response to temperature, indicating that these genes likely participate in spikelet development through the cooperative TSD1-YABBY module. These findings reveal a distinctive function of FHY3/FAR1 family genes and a unique TSD1-YABBY complex to acclimate spikelet development to high temperature in rice, providing insight into the regulating pathway of enhancing thermotolerance in plant reproductive development.

Bioinspired polydopamine-mediated metal-organic framework click-grafting aptamers functionalized fabric for highly-specific recognition of microcystin-leucine arginine.

Fabricating functional electrospun nanofiber coating for highly selective extraction of microcystin-LR (MC-LR) was of significant importance for water-safety monitoring. Herein, a novel MOF@aptamer functionalized nanofabric was presented via a facile and reliable strategy integrating polydopamine (PDA) mediation and thiol-ene chemistry and applied for specific recognition of the MC-LR model analyte. Using polydopamine (PDA) as the mediating layer, vinyl-UiO-66 MOF was grown in situ, followed by post-synthetic modification (PSM) of Zr4+ with vinyl phosphate and rapid UV-initiated click reaction of aptamers. Uniform deposition of Zr-based MOF (vinyl-UiO-66) on the nanofibers was directly produced, and the tedious co-electrospinning process was abandoned to prevent the aggregation and encapsulation of MOF. Via an efficient "thiol-ene" chemistry, massive thiol-terminated aptamers were grafted on MOF within one step under friendly conditions, rather than the time-consuming nanoparticle adsorption or unfriendly covalent chemical reactions. As a result, the robust MOF@aptamer-coated nano-fabrics were obtained, and a highly selective performance towards MC-LR was illustrated with a limit of detection (LOD) at 0.002 ng/mL, good precision (CV<8.3%), good repeatability (2.2∼6.0%) when coupled with LC-MS. Almost 1∼2 orders of magnitude higher detection sensitivity was exhibited than that of the common non-specific SPE/SPME fiber reported so far. Applied to water samples, the good matrix-resistance ability, and acceptable recovery yields were achieved with high specificity. This strategy might provide a rapid and friendly protocol to efficiently fabricate MOF@aptamer functionalized nano-fabrics through electrospinning and interfacial "thiol-ene" chemistry for highly-selective microextraction.

Facile one-step synthesis of graphene oxide/polyhedral oligomeric silsesquioxane composite-coated fiber for high-efficiency solid-phase microextraction of polycyclic musks.

Efficient fabrication of excellent fiber coatings for high-performance solid-phase microextraction (SPME) is interesting. Here, a high-efficiency synthesis strategy on graphene oxide/polyhedral oligomeric silsesquioxane (GO/POSS) composite-coated fiber was exploited via an ultra-fast UV polymerization in one step, and applied to excellent SPME of polycyclic musks (PCMs). Using methacryloxy siloxane-grafted GO and POSS-methacryl substituted (POSS-MA) as functional monomers, a facile and direct UV polymerization of multiple reactions including alkenyl radical reaction and thiol-ene click chemistry was fulfilled on thiol-pretreated fiber in only 5 min without tedious process. Characteristics such as morphology, FT-IR, XPS, BET and TG of fiber coating were studied in detail, as well as the SPME performance. Attributing to the rigid stereo conformation of POSS and large conjugate plane of GO-based nanosheet, the significant surface area, high hydrophobicity and intrinsic π-π interactions were adopted in fiber coating. In comparison of commercial SPME fibers, POSS-based or GO-based SPME fibers, a superior extraction performance towards PCMs was achieved with GO/POSS-coated fiber. High-efficiency extraction of PCMs was gained with prominent enrichment factors and the sensitive detection limits of PCMs were of 0.04-0.12 ng/L. In particular, the extraction efficiency was robust and still maintained a high level above 93% for PCMs even after 150 cycle's applications. Good recoveries of PCMs reached 86.6%-102.1% and 86.7%-101.3% in river water and cosmetic samples, respectively. It lights an attractive approach to efficiently fabricating robust GO/POSS-coated fiber for high-performance SPME of PCMs.

Remission of symptoms is not equal to functional recovery: Psychosocial functioning impairment in major depression.

The ultimate goal of depression treatment is to achieve functional recovery. Psychosocial functioning is the main component of functional impairment in depressed patients. The concept of psychosocial functioning has an early origin; however, its concept and connotation are still ambiguous, which is the basic and key problem faced by the relevant research and clinical application. In this study, we start from the paradox of symptoms remission and functional recovery, describe the concept, connotation, and characteristics of psychosocial functioning impairment in depressed patients, and re-emphasize its importance in depression treatment to promote research and clinical applications related to psychosocial functioning impairment in depressed patients to achieve functional recovery.

Efficient and selective solid-phase microextraction of polychlorinated biphenyls by using a three-dimensional covalent organic framework as functional coating.

Developing functional fiber coating for selective solid phase microextraction (SPME) of trace pollutants is critical in environmental analysis. Herein, the novel covalent organic frameworks (COFs) with three-dimensional (3D) frameworks and multiple interactions were designed and presented for the selective SPME of polychlorinated biphenyls (PCBs). Using tetra (p-aminophenyl) methane (TAM) and 1,3,5-triformylphloroglucinol (Tp) as the monomers, the 3D TpTAM-COF was synthesized and possessed a large specific surface area, high thermal stability, and spatial selectivity toward PCBs. Characterizations such as morphology, XPS, XRD, thermal stability, and enhancement factors (EFs) were studied. Multiple interactions including π-π conjugation, hydrophobic interaction, and selectivity toward non-planar structure were adopted, which resulted in a superior adsorption affinity toward PCBs on TpTAM-COF. Under the optimal conditions, the spatial selectivity toward PCBs, organic analogs (o-dichlorobenzene, biphenyl) and polycyclic aromatic hydrocarbons (naphthalene, pyrene, and anthracene)) was achieved. Efficient and selective adsorption of fifteen PCBs was fulfilled with the highest EF up to 10305. Using the HS-SPME-GC-MS method, the recoveries of PCBs in the river water and soil samples were determined to be 84.8 ± 7.8% ∼ 117.2 ± 8.5% (n = 3) and 84.4 ± 8.6% ∼ 114.7 ± 7.6% (n = 3), respectively. Compared with most commercial SPME fibers and other COFs-based fibers, the resultant TpTAM-COF-coated fibers possessed higher selectivity and EFs of PCBs. It proposed a promising approach for selective SPME of trace PCBs by multiple interactions in the steric structure of 3D COFs.

Usability and Effects of a Combined Physical and Cognitive Intervention Based on Active Video Games for Preschool Children.

Executive functions (EFs) are essential for early childhood development, and effective programs to improve EFs in preschool education are becoming increasingly crucial. There is rising evidence that combined physical-cognitive intervention training utilizing active video games (exergames) could be a viable strategy to improve EFs. However, there is a shortage of empirical evidence on the application of this approach in preschool education. The effectiveness of exergame intervention training in preschools must be evaluated. This study conducted a randomized controlled trial to assess the effects of exergames intervention training on preschool children's EFs. A total of 48 participants aged 4-5 years were enrolled; 24 were randomly allocated to receive exergames physical activity training, and the remaining 24 received conventional physical activity training. After a four-week intervention, the children who received the exergames intervention training exhibited considerably greater gains in all three EFs tasks than children who received the conventional physical activity program. Follow-up interviews revealed that the children accepted the exergames well. The results demonstrate the viability of incorporating exergames into preschool education to improve children's EFs, supporting prior findings and offering more empirical evidence from early childhood research.

LUX ARRHYTHMO Interacts With ELF3a and ELF4a to Coordinate Vegetative Growth and Photoperiodic Flowering in Rice.

The evening complex (EC) plays a critical role in photoperiod flowering in Arabidopsis. Nevertheless, the underlying functions of individual components and coordinate regulation mechanism of EC genes in rice flowering remain to be elucidated. Here, we characterized the critical role of LUX ARRHYTHMO (LUX) in photoperiod perception and coordinating vegetative growth and flowering in rice. Non-functional alleles of OsLUX extremely extended vegetative phase, leading to photoperiod-insensitive late flowering and great increase of grain yield. OsLUX displayed an obvious diurnal rhythm expression with the peak at dusk and promoted rice flowering via coordinating the expression of genes associated with the circadian clock and the output integrators of photoperiodic flowering. OsLUX combined with OsELF4a and OsELF3a or OsELF3b to form two ECs, of which the OsLUX-OsELF3a-OsELF4a was likely the dominant promoter for photoperiodic flowering. In addition, OsELF4a was also essential for promoting rice flowering. Unlike OsLUX, loss OsELF4a displayed a marginal influence under short-day (SD) condition, but markedly delayed flowering time under long-day (LD) condition. These results suggest that rice EC genes share the function of promoting flowering. This is agreement with the orthologs of SD plant, but opposite to the counterparts of LD species. Taken together, rice EC genes display similar but not identical function in photoperiodic flowering, probably through regulating gene expression cooperative and independent. These findings facilitate our understanding of photoperiodic flowering in plants, especially the SD crops.

Aptamer-functionalized metal-organic framework-coated nanofibers with multi-affinity sites for highly sensitive, selective recognition of ultra-trace microcystin-LR.

A novel aptamer-functionalized metal-organic framework nanofibrous composite (viz. PAN/UiO@UiO2-N3-aptamer) with a high aptamer coverage density was proposed based on the electrospinning and seeded growth method, and used for specific affinity recognition of trace Microcystin-LR (MC-LR). Heterobifunctional ligand was used to modify the metal-organic framework nanoparticles (MOF NPs) surface, which could passivate the MOF surface with respect to unmodified DNA, followed by coupling massive aptamers on MOF of the solid-phase microextraction (SPME) fiber using click chemistry. Characterizations including morphology, spectra analysis, mechanical stability, binding capacity and specificity were fulfilled. Applied to the analysis of MC-LR, the good selective and sensitive recognition were obtained with the detection limit as low as 0.003 ng/mL, which was better than most non-specific SPME or solid-phase extraction (SPE) protocols. The stability and reproducibility were acceptable, and the intra-day, inter-day and column-to-column relative standard deviations (RSDs) for the recovery of MC-LR were gained in the range from 2.5% to 14.3%, respectively. Satisfactory recoveries of MC-LR in environmental water samples were measured as 96.3 ± 4.7% - 98.9 ± 2.7% (n = 3) in tap water, 94.4 ± 2.5% - 96.1 ± 3.5% (n = 3) in pond water, and 97.0 ± 2.1% - 97.9 ± 3.1% (n = 3) in river water, respectively. This work demonstrated that the electrospun nanofibrous composite with massive aptamers would be a better alternative for ultra-trace MC-LR detection with good selectivity, matrix-resistance ability and high resolution.

Rapid polymerization of polyhedral oligomeric siloxane-based zwitterionic sulfoalkylbetaine monolithic column in ionic liquid for hydrophilic interaction capillary electrochromatography.

A novel polyhedral oligomeric siloxane (POSS)-based zwitterionic monolithic capillary column was prepared via one-pot polymerization in ionic liquid porogen, using N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine (DMMSA) and methacrylic ethyl trimethylammonium chloride (META) as binary functional monomers, and methacryl substituted POSS as cross-linker. The pore structure, permeability and homogeneity were well tuned by optimizing the polymerization conditions. The resultant monolith was characterized by scanning electron microscopy, nitrogen adsorption/desorption isotherm and Fourier transform infrared spectroscopy. The incorporation of zwitterionic ligand (DMMSA), quaternary amine group (META) and rigid POSS skeleton endows the hybrid organic-silica monolith with high hydrophilicity, electrostatic interaction and good mechanical stability, as well as a tunable electroosmotic flow over wide pH range. A close investigation of capillary electrochromatographic separations of different types of polar compounds such as bases, nucleosides and benzoic acids on such stationary phase exhibited a retention independent column efficiency up to 118,000 plates/m (thiourea), as well as a mixed-mode hydrophilic interaction chromatography (HILIC) retention mechanism including weak electrostatic interaction, hydrophobic interaction and anion exchange.

Aptamer-functionalized metal-organic framework-based electrospun nanofibrous composite coating fiber for specific recognition of ultratrace microcystin in water.

A novel aptamer@AuNPs@UiO-66-NH2 electrospun nanofibrous coating fiber for specific recognition of microcystin-LR (MC-LR) was proposed by using electrospinning, metal-organic frameworks (MOF) seed growth and AuNPs bridging aptamer strategies. Characterization of morphology, structure and stability of the obtained affinity nanofibrous coating fiber were investigated. High loading of MOFs and aptamers on the nanofibrous fiber were achieved and successfully applied for accurate identification of MC-LR by solid-phase microextraction (SPME) coupled with LC-MS. Highly specific recognition of MC-LR with little interference of analogs was achieved with extremely low LOD (0.004 ng/mL), good precision (CV% < 11.0%) and low relative error (RE% = -1.5% to -10.0%), which was rather better than that of the traditional SPME or SPE protocols. Satisfactory recoveries of MC-LR were obtained in the range of 92.0-96.8% (n = 3) in fortified tap water, raw pond water and river water samples. This work revealed an attractive alternative access to specific recognition and super-sensitive analysis of MC-LR in water.

In situ photo-initiated polymerized oligonucleotide-functionalized hydrophilic capillary affinity monolith for highly selective in-tube microextraction of ochratoxin A mycotoxin.

A photo-initiated polymerized oligonucleotide-grafted hydrophilic affinity monolithic column was synthesized in situ, and exploited for selective in-tube solid phase micro-extraction (IT-SPME) protocol towards the sensitive detection of ochratoxin A (OTA). Only 7 min was required for the rapid polymerization of aptamer-based affinity monolith, which was much less than the reaction time of most thermal polymerization (12-16 h) and sol-gel chemistry methods (up to 52 h). Characterizations such as polymerization recipes, structure morphology, FTIR spectrum, elemental mapping, mechanical stability, and specific recognition performance were evaluated. A significantly hydrophilic nature with a low contact angle of 15° was observed, and a mixed-mode mechanism including aptamer affinity recognition and hydrophilic interaction (HI) was employed. By coupling with HPLC-fluorescence detection, the highly specific online recognition performance was achieved with an extremely low nonspecific adsorption of the analogues. The calibration curve of OTA was obtained in the concentration range 0.05-50.00 ng·mL-1 with a limit of detection (LOD, S/N = 3) of 0.012 ng·mL-1. Applied to sample analysis, acceptable recovery yields of 95.1 ± 1.4% - 99.5 ± 2.2% (n = 3) were obtained in beer and red wine. The proposed method lighted a promising way to efficiently preparing a hydrophilic aptamer-affinity monolith for highly specific recognition of trace mycotoxin by IT-SPME coupled with HPLC. A hydrophilic oligonucleotide-based affinity capillary monolith was explored via in situ photopolymerization for overcoming low preparation efficiency and achieving high-performance online IT-SPME of OTA mycotoxin.

A facile aptamer immobilization strategy to fabricate a robust affinity monolith for highly specific in-tube solid-phase microextraction.

Developing a functional affinity monolithic column towards in-tube solid-phase microextraction (IT-SPME) for selective sample pretreatment is critical. Herein, a high-performance capillary affinity monolithic column with an ultra-high aptamer coverage density was rapidly fabricated via a simple adsorption strategy, in which aptamers with natural sequences were directly immobilized on an ammonium-based strongly cationic matrix. Limitations of the traditional biological or covalent methods such as time-consuming modification reactions, special requirement of active groups (e.g. -NH2 and -SH) on the aptamer, and low aptamer coverage density levels were avoided. An ultra-high coverage density of 8616 pmol µL-1 was achieved with excellent stability, and the highest aptamer-modification level among all the current methods was reached. Selective recognition and high recovery yields of the model mycotoxin ochratoxin A (OTA) were achieved in 95.9 ± 0.98%-97.9 ± 0.28% (n = 3). In particular, there was little cross-reactivity towards the OTB analogue of only 0.5% even in the case of 250 fold of the analogue OTB, which was not reported in previous affinity monoliths. Upon sample analysis, satisfactory discriminations of trace OTA were obtained at 93.7 ± 1.4%-95.5 ± 2.5% (n = 3) in beer and wheat. A facile and direct method for efficiently fabricating an aptamer-based affinity monolith towards online selective IT-SPME was proposed.

Towards highly specific aptamer-affinity monolithic column by efficient UV light-initiated polymerization in "one-pot".

Time-consuming or tedious operation in multiple-step process might is the obstacle for efficiently preparing aptamer-affinity monolithic column. Here, a new and facile strategy to prepare aptamer-based hybrid affinity monolith in "one-pot" at room temperature was exploited, in which UV light-initiated free-radical polymerization and "thiol-ene" click reaction were implemented simultaneously. Only 7 min was cost for finishing the polymerization reaction, which was only 1/100 of that for the traditional thermal polymerization. Using ochratoxin A (OTA) as the model analyte, the recipe for photo-initiated polymerization was optimized, and SEM morphology, FTIR, EDS, pore size distribution and specific recognition performance were also studied. Compared with traditional thermal polymerization, the resultant monolith was achieved more facilely and displayed better results such as more homogeneous skeleton structure, higher reaction efficiency of aptamer (>88.2%) and better specific selectivity to OTA. Besides, an extremely low nonspecific adsorption of analogues was obtained and showed a level at only 1/25 of that in the similar aptamer-affinity monolith prepared by thermal polymerization. Applied to beer and red wine samples, good recovery yields about 99.7 ± 4.0% -101.2 ± 2.3% (n = 3)was achieved with the acceptable RSDs. It would open up a rapid and promising access to efficiently preparing high-performance aptamer-based affinity monolithic columns for online specific recognition.

Heteroporous 3D covalent organic framework-based magnetic nanospheres for sensitive detection of bisphenol A.

Covalent organic frameworks (COFs) showed great promise in effective adsorption of target molecule via size selectivity. Although various magnetic 2D COFs composites have been studied and exhibited the intensive applications, the incorporation of 3D COFs and magnetic nanoparticles to form a new class of magnetic adsorbents with enhanced function still has no reports. Herein, a novel Fe3O4@3D COF with heteroporous structure matching to the sizes of bisphenol A (BPA) was firstly synthesized for better adsorption of BPA than common magnetic 2D-COFs. Three Fe3O4@3D COFs nanospheres were synthesized under the solvothermal conditions in autoclave, and the optimum Fe3O4@3D-COF denoted as Fe3O4@COF-TpTAM (Tp, 1,3,5-triformylphloroglucinol; TAM, tetra(p-aminophenyl)-methane) was selected and employed. Detailed characteristics of Fe3O4@COF-TpTAM were evaluated via various techniques including TEM, FTIR, TGA, XRD and BET. Excellent chemical and thermal stability, high surface area (294.6 m2 g-1) and pore volume (0.2 m3 g-1) with multiple pore sizes comparable with the simulated three-dimensional sizes of BPA were exhibited. A high adsorption capacity of BPA up to 209.9 mg/g that was better than common 2D-COFs was achieved, and the sensitive MSPE-LC-MS method with wide linear range (10-5000 pg/mL), low detection limit (4 pg/mL, S/N = 3) was built. Satisfactory recoveries of BPA as 93.8 ± 1.4%-101.4 ± 5.1% (n = 3) and 100.4 ± 1.9% ~ 107.3 ± 1.2% (n = 3) were obtained in milk and river water samples, respectively. This work demonstrates the promising application of Fe3O4@3D COF as efficient adsorbents of trace BPA, and opens up a new access for the efficient MSPE in sample pretreatment for food or environmental safety analysis.

Towards online specific recognition and sensitive analysis of bisphenol A by using AuNPs@aptamer hybrid-silica affinity monolithic column with LC-MS.

Highly specific sample pretreatment for the sensitive detection of trace bisphenol A (BPA) in compliacted samples is critical. Herein, a new protocol towards online specific recognition and sensitive detection of BPA was proposed by using Aptamer@AuNPs-modified affinity monolith coupled with LC-MS. Optimization of polymerization conditions and characterization such as the morphology, energy spectrum, mechanical stability, aptamer coverage density and specific performance of the affinity monolith were studied. Nano-gold particles (AuNPs) densely distributed on the rigid hybrid-silica substrates, and an unusually high aptamer coverage density reached 3388 pmol/µL, which was favorable to fulfill the effective identification of BPA with high selectivity and inhibit the interference of analogs including BPB and BPC. A highly sensitive recognition of BPA was obtained with the limit of detection (LOD) as low as 0.02 ng/mL. Applied to dairy milk products and serum samples, trace BPA could be sensitive detected by this strategy, while the poor response was achieved by using traditional non-specific SPE column for sample pretreatment. Satisfactory recoveries of fortified BPA were measured as 97.45 ± 2.24%-98.03 ± 4.36% (n = 3) in powdered infant formulas, 96.64 ± 3.37% ~ 99.42 ± 3.22% (n = 3) in bottled milk, 94.69 ± 2.15% ~ 100.96 ± 1.94% (n = 3) in boxed milk, and 93.71 ± 1.53% ~ 96.73 ± 2.56% (n = 3) in children serum samples, respectively. This protocol lights a new access to online specific identification of trace BPA from complex matrix with good detection sensitivity by using aptamer-affinity monolithic column.