查找使用阿拉丁产品的科研文献

An ultrasensitive and long-lasting chemiluminescence immunoassay for IP-10 detection based on a 4-bromophenol-reinforced bienzymatic system

Jiang Chang,Deying Zou,Honglin Ren,Xilin Liu,Meng Li,Zhaozhao Si,Cheng Han,Zengshan Liu,Shiying Lu,Pan Hu

The 10-kDa chemokine interferon-gamma-inducible protein 10 (IP-10) is considered one of the most promising biomarkers for diagnosing both tuberculosis and COVID-19 infections. The blood samples of patients at different disease states contain different levels of IP-10, which need to be detected in a rapid, specific and ultrasensitive manner. Here, we report a bienzymatic chemiluminescence sandwich immunoassay (BCSI) assay for the ultrasensitive and stable detection of IP-10. In this assay, IP-10 is first efficiently captured using a double-antibody sandwich strategy. The detection antibody is linked to catalase (CAT) via a streptavidin–biotin signal amplification system to achieve highly efficient conversion of hydrogen peroxide (H 2 O 2 ) to oxygen and water. In the chemiluminescence (CL) reaction, horseradish peroxidase (HRP) acts as an efficient catalyst, and 4-bromophenol acts as an enhancer for the cyclic transition of HRP, which results in a strong and durable CL signal. The bienzymatic catalysis with CAT and HRP and the potentiation of 4-bromophenol enables the assay to be ultrasensitive and stable. The CL intensity was found to be well correlated with the detection of IP-10 at levels in the range of 0.71 to 125,000 pg/mL, which covers more than 6 orders of magnitude, with a detection limit of 0.63 pg/mL. The coefficient of variation was 1.49%, and the recovery range of IP-10 in serum was 86.21%-104.57%. This assay provides a wide linear range and high sensitivity and may be a promising method for the high-throughput detection of IP-10 in the diagnosis of tuberculosis and COVID-19.

Simultaneous detection of multiple phenolic compounds in fish by gas chromatography-mass spectrometry following a modified QuEChERS cleanup

Jiali Xing,Yang Li,Ruihang Zheng,Hao Shen,Xiaorong Xu,Lingyan Mao,Xiaohu Luo,Jian Shen,Weirong Yao

Preparation of a novel heterogeneous palladium nanocatalyst based on carboxyl modified magnetic nanoparticles and its applications in Suzuki-Miyaura coupling reactions

Fangfang Ren,Simin Li,Wenqing Zheng,Qianyi Song,Wenhui Jia,Yaqin Nan,Haijiao Jia,Jia Liu,James Jianmin Bao,Youxin Li

In this paper, an active, recyclable and stable magnetic palladium nanocatalyst (Fe 3 O 4 @SiO 2 -DTPA-Pd) was reported which could catalyze Suzuki coupling reaction. The Pd was stably hold by the three nitrogen atoms at the inside and four acetic acid groups at the outside of the chelating ligand ethylenediaminepentaacetic acid (DTPA) on the surface of core-shell magnetic Fe 3 O 4 @SiO 2 microspheres . The prepared Fe 3 O 4 @SiO 2 -DTPA-Pd was systematically characterized. Results showed its size was 10–20 nm with 0.535 mmol/g Pd 2+ /Pd 0 . It could monodisperse in liquid, was thermally stable and good magnetic response from the high saturation magnetization value at 35.9 emu/g. Its activity was evaluated through Suzuki coupling reactions between 14 types of aryl halides and phenylboronic acid under optimized reaction conditions. It exhibited excellent activities and good applicability to substituted iodobenzene and bromobenzene . The yield of 4-bromobenzonitrile was up to 97.93%. Furthermore, the Fe 3 O 4 @SiO 2 -DTPA-Pd catalyst was stable, reusable and conveniently recovered by applying an external magnetic field. After 20 consecutive reaction cycles, the yield was still above 85%, which showed a superior heterogeneous advantage over other catalysts reported in the literature and had the huge potential in actual application of industry.

Zeolite-encaged palladium catalysts for heterogeneous Suzuki-Miyaura cross-coupling reactions

Mingyang Gao,Jiamin Wang,Weixiang Shang,Yuchao Chai,Weili Dai,Guangjun Wu,Naijia Guan,Landong Li

Suzuki-Miyaura cross-coupling reaction by homogeneous Pd complex is a powerful route to construct carbon-carbon bond and is now widely applied in the synthesis of functional organic compounds. Heterogeneous Pd catalysts are highly desired as alternatives to homogeneous ones due to their facile reusability and good compatibility. Herein, zeolite-encaged Pd particles, namely Pd@MFI, have been successfully prepared via an in-situ hydrothermal strategy and investigated as promising heterogeneous catalysts for Suzuki-Miyaura cross-coupling reactions. Characterization results demonstrate that high dispersed Pd particles with apparent sizes of 1–2 nm have been encaged in and efficiently stabilized by the matrix of MFI zeolite. The as-prepared Pd@MFI catalysts are active in the Suzuki-Miyaura coupling reaction between bromobenzene and phenylboronic acid, and the presence of basic sites adjacent to Pd sites are crucial to achieving high catalytic activity via effective cooperation. Pd@K-ZSM-5 can be optimized for the coupling between bromobenzene and phenylboronic acid and can catalyze the reaction with a low apparent activation energy value of 41.2 kJ/mol. Pd@K-ZSM-5 also shows good stability and can be recycled for at least five times without obvious loss in activity, demonstrating its great potential as a heterogeneous catalyst for Suzuki-Miyaura cross-coupling reactions. Encapsulation of metal species in zeolite matrix offers a big opportunity to the heterogenization of homogeneous metal catalysts for practical chemical transformations.

Simultaneous detection of multiple phenolic compounds in shrimps through gas chromatography–mass spectrometry coupled with a modified QuEChERS

Xing Jiali,Xu Xiaorong,Li Yang,Chen Cancan,Mao Lingyan,Luo Xiaohu,Shen Jian,Cheng Hai,Zhang Shufen,Guo Yahui,Gan Ning

Owing to the difficult degradation of phenolic compounds, the existence of phenolic compound residues accumulated through the food chain in crustaceans and their effects on human health have garnered considerable and more attention. However, the current detection methods for phenolic compounds are not only complex and time-consuming but can also detect fewer types of phenols simultaneously. Thus, a simple, high-throughput method without derivatization for the determination of 18 phenolic compounds in crustaceans was developed using a modified QuEChERS sample preparation method combined with gas chromatography-mass spectrometry. The results indicated that the average recovery of the 18 phenolic compounds was 80.2–106.5% at three spiked levels, and the relative standard deviation was 2.6–12.4%. The limits of detection and quantitation were 0.001–0.014 and 0.003–0.042 mg/kg, respectively. Good linear relationships were observed for the phenolic compounds in their corresponding concentration ranges ( R 2  > 0.999). The applicability of the method was assessed by analyzing 16 actual shrimp samples, among which five samples contained residues ranging from 0.013 to 0.042 mg/kg. Moreover, the establishment of this method has important theoretical and practical significance for the determination and control of the residue levels of phenolic compounds in crustaceans. In addition, it can provide a reference for the development of similar detection standard methods in the future.

Kinetic modeling and mechanisms of parahalogenated phenols degradation by UV222/H2O2

Min Zhao,Ting Li,Yizhan Zhang,Jiaming Gan,Yiting Zhao,Xin Yu,Lei Wang

Advanced oxidation technology of KrCl excimer lamp activated H 2 O 2 (UV 222 /H 2 O 2 ) have been received widespread attention in the field of water treatment recently, due to the higher radical yield and environmentally friendly nature compared to UV 254 /H 2 O 2 . In this investigation, four representative parahalogenated phenols (HPs) degradation kinetic and mechanisms by UV 222 alone and UV 222 /H 2 O 2 were studied, respectively. The results showed that the photolysis rate constants ( k obs ) under UV 222 followed the order of p -Chlorophenol ( p -CP) >  p -Fluorophenol ( p -FP) >  p -Bromophenol ( p -BP) >  p -Iodophenol ( p -IP), and the degradation rate constants ( k obs ) by UV 222 /H 2 O 2 followed the order of p -FP >  p -CP >  p -BP >  p -IP. The molar absorption coefficient ( ε 2 22nm ) and quantum yield ( Φ 222nm ) of HPs photolysis were measured. Kinetic model simulating results are in fair agreement with the experimental results. Through HPLC-MS analysis and DFT calculation, the impact of halogen ions on the degradation kinetics of HPS by UV 222 and UV 222 /H 2 O 2 was found, the possible reaction pathways and mechanisms were proposed. Compared with UV 254 /H 2 O 2 for removing p -CP, UV 222 /H 2 O 2 was much more energy efficient.

Self-carbon-thermal-reduction strategy for boosting the Fenton-like activity of single Fe-N4 sites by carbon-defect engineering

Wei Shengjie,Sun Yibing,Qiu Yun-Ze,Li Ang,Chiang Ching-Yu,Xiao Hai,Qian Jieshu,Li Yadong

Carbon-defect engineering in metal single-atom catalysts by simple and robust strategy, boosting their catalytic activity, and revealing the carbon defect-catalytic activity relationship are meaningful but challenging. Herein, we report a facile self-carbon-thermal-reduction strategy for carbon-defect engineering of single Fe-N 4 sites in ZnO-Carbon nano-reactor, as efficient catalyst in Fenton-like reaction for degradation of phenol. The carbon vacancies are easily constructed adjacent to single Fe-N 4 sites during synthesis, facilitating the formation of C-O bonding and lowering the energy barrier of rate-determining-step during degradation of phenol. Consequently, the catalyst Fe-NCv-900 with carbon vacancies exhibits a much improved activity than the Fe-NC-900 without abundant carbon vacancies, with 13.5 times improvement in the first-order rate constant of phenol degradation. The Fe-NCv-900 shows high activity (97% removal ratio of phenol in only 5 min), good recyclability and the wide-ranging pH universality (pH range 3-9). This work not only provides a rational strategy for improving the Fenton-like activity of metal single-atom catalysts, but also deepens the fundamental understanding on how periphery carbon environment affects the property and performance of metal-N 4 sites.

Engineering the atomic interface of porous ceria nanorod with single palladium atoms for hydrodehalogenation reaction

Li Zhijun,Zhang Mingyang,Zhang Lili,Dong Xiuli,Leng Leipeng,Horton J. Hugh,Wang Jun

Tuning the electronic properties of single atom catalysts (SACs) between the central metal and the neighboring surface atoms has emerged as an efficient strategy to boost catalytic efficiency and metal utilization. Here we describe a simple and efficient approach to create atomically dispersed palladium atoms supported over defect-containing porous ceria nanorod containing palladium up to 0.26 wt.%. The existence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements. This catalyst shows excellent efficiency in hydrodehalogenation reactions at low H 2 pressure under mild conditions, along with satisfactory recyclability and scalability. Density functional theory (DFT) calculations reveal that the high activity stems from the spatial isolation of palladium atoms and the modified electronic structure of palladium confined in defect-containing ceria nanorod. This work may lay the foundation for the facile creation of single atom catalysts within the synthetic community and shed light on the possibility for scale-up production.

Selective Oxidation of Various Phenolic Contaminants by Activated Persulfate via the Hydrogen Abstraction Pathway

Cong Wang,Shao-Yi Jia,You Han,Yang Li,Yong Liu,Hai-Tao Ren,Song-Hai Wu,Xu Han

Enzymatic polymerization of phenolic contaminants to polyphenolics by H2O2 is an effective method to turn phenolic wastes to useful polymers. However, the sensitivities and the high costs of enzymes always limit their applications in the long-run treatment of industrial wastewater. In this study, a highly efficient CuO-persulfate (PS) system is reported to be a promising candidate for enzyme–H2O2 and shows high reactivity to polymerize various phenolic contaminants to polymers under alkaline conditions with the ratio of PS/phenolics less than 2.0. Compared with the generally accepted mechanism that the oxidizing species of SO4•– and ·OH generated during PS activation primarily contribute to the oxidation of various organic contaminants, quenching experiments, EPR (electron paramagnetic resonance) analysis and DFT calculations in this study indicate that PS is activated on CuO via a nonradical pathway under alkaline conditions, and the O–O bond in PS is moderately elongated from 1.45 to 1.58 Å. The inversely linear relationship between log kobs and BDEO–H values of various phenolics in the Hammett plot confirms H-abstraction from various phenolics under alkaline conditions. DFT calculations further reveal the formation of phenolic radicals after the activated PS abstracts H from phenolic −OH, followed by subsequent polymerization of phenoxyl radicals to polyphenolics. Characterizations of the oxidation products confirm that more than 80% phenolic contaminants have been transformed to polyphenolics. This study provides a new alternative for recovering various phenolic contaminants from industrial wastewater.

A photo-switch for peroxydisulfate non-radical/radical activation over layered CuFe oxide: Rational degradation pathway choice for pollutants

Junqin Liu,Pingxiao Wu,ShanShan Yang,Saeed Rehman,Zubair Ahmed,Nengwu Zhu,Zhi Dang,Zehua Liu

This work presents a novel strategy for peroxydisulfate (PDS) activation under controlled non-radical/radical mechanism, which is based on a photo-switch over layered CuFe oxide (CFO). The non-radical mechanism is attained by CFO under dark environment, and the radical mechanism is achieved through the visible light irradiation. Electron paramagnetic resonance (EPR) and density functional theory (DFT) studies demonstrate the non-radical activation mechanism is conducted by the polarization effect of CFO to PDS molecule. The radical mechanism could be elucidated by the one-electron reduction of the PDS by excited electrons on conduction band of CFO. Products analyses based on HPLC-MS and Fukui functions suggest that the non-radical degradation pathway could decrease the generation of halide intermediates, whereas the radical pathway may not be observed with this property. Quantitative structure-activity relationships (QSARs) were established between the observed pseudo-first-order rates of various phenolic pollutants and the classical descriptors (i.e., Hammett constant, Pka, E HOMO and E LUMO ) in the non-radical and radical systems, respectively, to give instructions of pathway choice for different pollutants. Considering the non-radical/radical pathway both have their own unique strengths (e.g., non-radical pathway has high selectivity to pollutants and high utilization efficiency of oxidant, and radical pathway has considerable degradation rate and strong mineralization ability), these pathways should be chosen wisely for pollutant degradation according to reality conditions.

p-Bromophenol-Enhanced Bienzymatic Chemiluminescence Competitive Immunoassay for Ultrasensitive Determination of Aflatoxin B1

Juan Li,Xu Zhao,Li-Jian Chen,Hai-Long Qian,Wen-Long Wang,Cheng Yang,Xiu-Ping Yan

Aflatoxin B1 (AFB1) contamination is one of the most critical global issues in food safety. The high carcinogenic nature necessitates rapid and specific methods for the determination of AFB1 in foodstuffs at ultratrace levels. Here, we report an enhanced bienzymatic chemiluminescence competitive immunoassay for ultrasensitive and high-throughput determination of AFB1. In this assay, protein G was first coated on the wells of a microplate for recognizing the Fc fragment of anti-AFB1 mAbs to reduce the antibody dosage and guarantee high immunological reaction efficiency. The target AFB1 competed with glucose oxidase labeled AFB1 for the limited anti-AFB1 mAbs in the wells of the microplate. p-Bromophenol was employed as an enhancer to obtain intense and long-lasting chemiluminescence. The utilization of an enhancer and bienzymatic catalysts effectively improved the detection sensitivity. The developed method offered a good linearity over 5 orders of magnitude, a detection limit of 5 pg L–1, and a relative standard deviation of 1.9% for AFB1. The application of the developed method to the analysis of grain samples gave quantitative recoveries from 94.0% to 97.0%. The developed method provides a universal platform for high-throughput, ultrasensitive, and high specific detection of pollutants or nutrients in foods.

The effect of phenolic compounds on salicylaldimine nickel-catalyzed ethylene oligomerization

Jun Wang,Junyi Xie,Libo Wang,Yan Jiang,Na Zhang

A salen nickel complex has been prepared in good yield with ethylenediamine, salicylaldehyde, and NiCl2·6H2O as raw materials. The structure of the complex was characterized by FTIR, 1H NMR, UV, and ESI-MS. Upon activation with methylaluminoxane (MAO), the precatalyst showed high activity for ethylene oligomerization. To reduce the simultaneous production of insoluble polymers during the nickel-catalyzed ethylene oligomerization, a series of phenolic compounds were introduced as modifiers for the production of linear α-olefins. The researched result showed that the phenolic compounds have a significant impact on the selectivity of oligomers and the concentration of polymers. With the increase of phenolic compounds, the content of polymers decreased and the distribution of oligomers gradually shifted toward lighter olefins. The sterically hindered 4-tert-butyphenol proved to be an especially efficient polymer-retarding modifier among the studied phenolic compounds in this work. Furthermore, the retarding effect of phenolic compounds toward insoluble polymers may be mainly related to their interaction with MAO, giving rise to larger MAO aggregates.