Preparation of Fe3O4@C@PANI magnetic microspheres for the extraction and analysis of phenolic compounds in water samples by gas chromatography-mass spectrometry

In this work, core-shell structure Fe(3)O(4)@C@polyaniline magnetic microspheres were synthesized using simple hydrothermal reactions. The carbon-coated magnetic microspheres (Fe(3)O(4)@C) were first synthesized by a hydrothermal reaction, and then aniline was polymerized on the magnetic core via another hydrothermal reaction. Then, the obtained Fe(3)O(4)@C@polyaniline magnetic microspheres were applied as magnetic adsorbents for the extraction of aromatic molecules due to π-π interactions between polyaniline shell and aromatic compounds. In our study, five kinds of phenols including phenol, 2,4-dichlorophenol (DCP), 2,4,5-trichlorophenol (TCP), pentachlorophenol (PCP) and bisphenol A (BPA) were selected as the model analytes to verify the extraction ability of Fe(3)O(4)@C@PANI microspheres. After derivatization, the phenols were detected using gas chromatography-mass spectrometry (GC-MS). The dominant parameters affecting enrichment efficiency were investigated and optimized. Under the optimal conditions, the proposed method was evaluated, and applied to the analysis of phenols in real water samples. The results demonstrated that our proposed method based on Fe(3)O(4)@C@polyaniline magnetic microspheres had good linearity (r(2)>0.991), and limits of quantification (2.52-29.7 ng/mL), high repeatability (RSD<13.1%) and good recovery (85.3-110.6%).     

Recent advance in synthesis and application of heteroatom zeolites

Incorporation of heteroatoms into the framewo rk of zeolites has become a significant strategy to improve their performance in catalysis and adsorption,because the obtained heteroatom zeolites exhibit quite different properties from the conventional aluminosilicate zeolites in aspects of surface acidity,pore structures,particle size and so on.In this review,the progress on the heteroatom zeolites including their synthesis and application is highlighted.First,the recent advance on the design and synthesis of different heteroatom zeolites is summarized.Special emphasis is placed on the introduction and comparison of three typical methods,including the direct synthesis,post synthesis and improved direct synthesis,for the traditional heteroatom zeolites(such as TS-1,Sn-MFI,Sn-β) and newly-reported heteroatom zeolites(such as W-MFI,Mo-MFI).According to their intrinsic characteristics,the application of heteroatom zeolites in diverse fields,such as production of fine chemicals,air pollution control and biomass conversion is then discussed.Finally,the challenges and perspective on the future development of heteroatom zeolites in low-cost preparation and practical application are proposed.     

Sensitive Analysis of Wilforidine in Human Plasma by LC-APCI-MS/MS

Wilforidine is a potentially efficient medicine to cure autoimmune diseases. In this paper, a sensitive and selective liquid chromatographic method coupled with atmospheric -pressure chemical ionization mass spectrometry (LC–APCI–MS/MS) has been developed for quantification of wilforidine in human plasma. Samples were deproteinized with acetonitrile and cleaned by solid-phase extraction. The chromatographic separation was performed on an analytical RRHD C₁₈ column (50 × 2.1 mm) using ammonium acetate solution (10.0 mmol L^?1)/acetonitrile (30/70, v/v) as the mobile phase at a flow rate of 0.7 mL min^?1. Detection was carried out by the positive multiple reaction monitoring mode with transitions of m/z 780 → 684 for wilforidine, and 646 → 586 for aconitine (internal standard), respectively. The calibration curve was linear (r = 0.9991) in the concentration range of 0.5–100.0 μg L^?1 with a lower limit of quantification of 0.5 μg L^?1 in plasma. Intra- and inter-day relative standard deviations were less than 6.8 and 13.1 %, respectively, and the recoveries were between 88.0 and 96.0 %. This accurate and highly specific assay provides a useful method for evaluating the pharmacokinetics of wilforidine in human plasma.     

High Glass Transition and Optical Transparency of Novel Organosoluble Polyamides Containing 4‐tert‐‐Butyltoluene Moiety

A series of novel polyamides 3a – 3d containing 4‐tert‐butyltoluene moiety, were prepared using the phosphorylation polycondensation technique. FT‐IR and ¹H NMR techniques were used to investigate the chemical structures of 3a–3d . The results confirmed that they agreed with the proposed structures for 3a – 3d completely. The 3a – 3d had inherent viscosities ranging from 0.71 to 1.67 dL·g⁻¹. All the polyamides showed excellent solubility, with the dissolvability at a concentration of 10 wt% in most amide polar solvents. Flexible and tough polyamide films could be prepared by casting from DMAc (N,N‐dimethylacetamide) solvent. Their films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range of 346–363 nm and transmittance higher than 80% at 450 nm. They also exhibited high glass transition temperatures in the range of 310–343°C and the onset decomposition temperatures in the range of 435–462°C in nitrogen atmosphere. Meanwhile, these polyamide films possess good mechanical properties with tensile strengths of 76.4–86.1 MPa and elongations at break of 11.2%–27.3%. Due to those properties, these polyamides could be considered as photoelectric and microelectronic materials.     

Progress of the key materials for organic solar cells

Organic solar cells have attracted academic and industrial interests due to the advantages like lightweight, flexibility and roll-to-roll fabrication. Nowadays, 18% power conversion efficiency has been achieved in the state-of-the-art organic solar cells. The recent rapid progress in organic solar cells relies on the continuously emerging new materials and device fabrication technologies, and the deep understanding on film morphology, molecular packing and device physics. Donor and acceptor materials are the key materials for organic solar cells since they determine the device performance. The past 25 years have witnessed an odyssey in developing high-performance donors and acceptors. In this review, we focus on those star materials and milestone work, and introduce the molecular structure evolution of key materials. These key materials include homopolymer donors, D-A copolymer donors, A-D-A small molecular donors, fullerene acceptors and nonfullerene acceptors. At last, we outlook the challenges and very important directions in key materials development.     

二价Ba2+、Pb2+和四价Ti4+在硼硅酸盐玻璃系统中对Li+/Na+离子交换的影响

本文讨论了在硼硅酸盐玻璃系统中引入二价Ba²⁺、Pb²⁺和四价Ti⁴⁺后,由于Pb²⁺和Ti⁴⁺配位结构的变化,引起Pb²⁺、Ti⁴⁺场强及其与O^2-离子间距的变化,对Li⁺/Na⁺离子交换产生影响,从而改变折射率差值(ΔN)和折射率分布.     

电离平衡综合探新

基础无机中,电离平衡包括弱电解质的电离平衡和盐类水解平衡两部分,其中概念公式多,学生在学习的过程中,常常出现错记、混记的现象。鉴于此,我们对该部分内容进行了归纳与综合的研究,建立了电离平衡主体概念原理图及主体计算图。实践证明,这种综合图式既有利于教师的教,又有利于学生的学。一、电离平衡主体概念与原理日电离平衡是化学平衡的其中一种具体表现形式,因而,其主体概念与原理无外乎是平衡、平衡常数、平衡转化率及影响平衡移动的因素等,仅仅是这些概念或原理对于电离平衡而言重新赋予新的名称而已。据此,我们建立了电…     

High solubility and optical transparency of novel polyimides containing 3,3′,5,5′-tetramethyl pendant groups and 4-tert-butyltoluene moiety

A series of novel polyimides (3a–d) were prepared from 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenyl-4”-tert-butyltoluene (1) with four aromatic dianhydrides via a one-step high-temperature polycondensation procedure. The obtained polyimides showed excellent solubility, with the dissolvability at a concentration of 10 wt% in most amide polar solvents and chlorinated solvents. Their films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range of 322–350 nm and the wavelength of 80% transparency in the range of 395–414 nm. They also showed low dielectric constant (2.72–2.91 at 1 MHz) and low water absorptions (0.37–0.62%). Moreover, these polyimides possessed high glass transition temperatures (T_g) (above 321 °C) and good thermal stability with 10% weight loss temperatures in the range of 526–547 °C in nitrogen atmosphere. In comparison with the analogous polyimides non-containing 3,3′,5,5′ -tetramethyl pendant groups, the resultant polyimides 3a–d showed better solubility, higher optical transparency and lower dielectric constant.