表面增强拉曼光谱检测二噁英类化合物研究进展

以二噁英及二噁英类多氯联苯为代表的持久性有机污染物(POPs), 具有致畸、致癌、致突变的性质, 被国际癌症研究中心列为人类一级致癌物. POPs通过环境进入食物链对食品安全造成威胁和影响. 以表面增强拉曼光谱(SERS)为代表的新型快速检测技术具有高灵敏分析的特点. 本综述总结了近年来基于SERS技术分析POPs的研究进展, 归纳了不同类型增强基底, 提出了SERS分析POPs的若干关键技术难点, 并对未来SERS技术在POPs分析方面的发展进行了展望.     

A facile method for preparation of green and antibacterial hydrogel based on chitosan and water-soluble 2,3-dialdehyde cellulose

Cellulose - Chitosan (CS) has been widely used to prepare natural hydrogel duo to its characteristics. However, most of the methods of preparing CS-based hydrogel are complicated and not green,...     

Investigation of the adsorption behavior of glycine peptides on 12% cross-linked agarose gel media

The highly cross-linked 12% agarose gel Superose 12 10/300 GL causes retardation of glycine peptides when mobile phases containing varying concentrations of acetonitrile in water are used. An investigation has been made into the retention mechanism behind this retardation using the glycine dipeptide (GG) and tripeptide (GGG) as models. The dependence of retention times of analytical-size peaks under different experimental conditions was interpreted such that the adsorption most probably was caused by the formation of hydrogen bonds but that electrostatic interactions cannot be ruled out. Thereafter, a nonlinear adsorption study was undertaken at different acetonitrile content in the eluent, using the elution by characteristic points (ECPs) method on strongly overloaded GG and GGG peaks. With a new evaluation tool, the adsorption energy distribution (AED) could be calculated prior to the model selection. These calculations revealed that when the acetonitrile content in the eluent was varied from 0% to 20% the interactions turned from (i) being homogenous (GG) or mildly heterogeneous (GGG), (ii) via a more or less stronger degree of heterogeneity around one site to (iii) finally a typical bimodal energy interaction comprising of two sites (GG at 20% and GGG at 10% and 20%). The Langmuir, Tóth and bi-Langmuir models described these interesting adsorption trends excellently. Thus, the retardation observed for these glycine peptides is interpreted as being of mixed-mode character composed of electrostatic bonds and hydrogen bonds.     

Sensitive immunoassay for the β-agonist ractopamine based on glassy carbon electrode modified with gold nanoparticles and multi-walled carbon nanotubes in a film of poly-arginine

We are presenting an electrochemical immunosensor for the determination of the β-agonist and food additive ractopamine. A glassy carbon electrode (GCE) was modified with gold nanoparticles and a film of a composite made from poly(arginine) and multi-walled carbon nanotubes. Antibody against ractopamine was immobilized on the surface of the modified GCE which then was blocked with bovine serum albumin. The assembly of the immunosensor was followed by electrochemical impedance spectroscopy. Results demonstrated that the semicircle diameter increases, indicating that the film formed on the surface hinders electron transfer due to formation of the antibody-antigen complex on the modified electrode. Under optimal conditions, the peak current obtained by differential pulse voltammetry decreases linearly with increasing ractopamine concentrations in the 0.1 nmol?L^?1 to 1 μmol?L^?1 concentration range. The lower detection limit is 0.1 nmol?L^?1. The sensor displays good stability and reproducibility. The method was applied to the analysis of spiked swine feed samples and gave satisfactory results. Figure

Immunoassay for ractopamine based on glassy carbon electrode modified with gold nanoparticles and a film of a composite made from poly (arginine) and multi-walled carbon nanotubes was proposed. Under optimal conditions, the peak currents obtained by differential pulse voltammetry decreases linearly with increasing ractopamine concentrations in the 0.1 nmol?L^?1 to 1 μmol?L^?1 concentration range. The detection limit is 0.1 nmol?L^?1.     

β-Cyclodextrin modified filter paper based solid phase extraction–room temperature phosphorimetry for preconcentration and determination of nitrogen heterocyclic compounds in water samples

A highly selective method for the preconcentration and the determination of nitrogen heterocyclic compounds (NHCs) by solid phase extraction–room temperature phosphorimetry (SPE–RTP) was described. The β-cyclodextrin (β-CD) coated filter paper was synthesized and used as the SPE membrane and the substrate for the measurement of RTP emission of NHCs in water samples. The RTP characteristics of NHCs on the coated filter paper were studied. The conditions for the measurement of RTP intensities of NPAHs were discussed and optimized in detail. Several experimental parameters related to the preconcentration of NHCs on the coated filter paper were also examined. The experimental results showed that the β-CD coated filter paper could selectively extract NHCs containing three benzene rings with a high enrichment efficiency. The limit of detections of carbazole, 7,8-benzoquinoline and phenanthridine were found to be 9.1 × 10⁻¹⁴, 8.3 × 10⁻¹³ and 7.8 × 10⁻¹³ mol mL⁻¹, respectively. The proposed method was applied to the analysis of NHCs in water samples. The recoveries of carbazole, 7,8-benzoquinoline and phenanthridine in water samples was in the range of 86.1–109.3%.     

质子辐照对有机硅树脂增强甲基硅橡胶的性能损伤及机理

硅橡胶具有优良的电绝缘性以及耐高低温、耐电晕、耐化学腐蚀、耐大气老化、耐臭氧和耐辐射等性能，近年来在航天领域得到了广泛应用．在宇宙空间的带电粒子如质子、电子等的辐照作用下，硅橡胶会发生性能退化，其质损率上升，产生析气现象，从而直接影响航天器的可靠性和寿命．自80年代以来，人们就对不同辐照源及不同粒子注量对硅橡胶材料的影响进行了研究，但直到近几年才将研究热点转向辐照场中硅橡胶的性能退化及微观结构的演变规律，其辐照环境大多集中于γ射线、Si^＋和F^＋离子、He^2＋离子等．对于空间环境下带电粒子辐照对硅橡胶材料的影响，国外由于相应的研究工作保密性强，报道甚少；国内哈尔滨工业大学则对我国自行研制的白炭黑增强空间级甲基硅橡胶质子辐照作用后的性能与微观结构的变化做了较为深入的研究。     

单波长编码计算机制彩色彩虹全息图的研究

提出计算机制三维物体彩色全息图的新方法.通过理论分析表明,在满足一定的条件下,三个不同原色的点光源所产生的全息图光栅结构和距全息图不同距离的三个同色物点的光产生的全息图光栅结构是等价的.根据这一原理并参照彩虹全息技术,研究了物体三原色信息光分布的编码方法和全息图的算法,用单波长计算实现彩色全息图的制作,同时,较为完满地解决了全息图叠加和色串扰问题.实验结果证明了该方法的可行性及有效性.     

基于课堂演示实验的大学物理隐性思政教育

介绍了大学物理课堂演示实验在课程隐性思政教育中具有独特的优势,并结合教学实践给出在大学物理课堂演示实验中开展隐性化课程思政教育的策略.以课堂演示实验作为大学物理课程隐性思政教育的切入点,可以有效地实现"润物无声"式课程思政隐性教育,在潜移默化中实现立德树人.     

An aptamer based assay for the β-adrenergic agonist ractopamine based on aggregation of gold nanoparticles in combination with a molecularly imprinted polymer

A sensitive visual aptamer-based assay is presented for the determination of ractopamine (RAC) in animal feed beef. In the absence of RAC, the aptamer binds to gold nanoparticles (AuNPs) and this prevents the AuNPs to undergo salt-induced aggregation which usually is accompanied by a color change from red to blue. If however, RAC is present, it will bind to the aptamer while the AuNPs remain uncoated so that aggregation and a color change will occur due to salt-induced aggregation. This can be monitored by spectrophotometer or even with bare eyes. Under optimal conditions, the aptasensor exhibits a linear range that covers the 10 to 400 ng.mL￣¹ RAC concentration range. The limit of detection is as low as 10 ng.mL￣¹. In order to further improve selectivity, a RAC-selective molecularly imprinted membrane was prepared and used to pre-extract RAC from complex samples. The combined method (molecularly imprinted membrane and aptasensor) was applied to the determination of RAC in spiked animal feed and beef and gave recoveries that ranged from 72.7 % to 87.3 % for complete feed and from 78.2 % to 86.5 % for beef, respectively.

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Graphical abstract A sensitive visual aptamer-based assay based on aggregation of gold nanoparticles in combination with a molecularly imprinted polymer was developed for the determination of ractopamine (RAC) in animal feed and beef.

     

光学干涉在二次电光系数测量中的应用与分析

为了更加深入地掌握光学干涉原理以及晶体材料的电光效应,我们搭建了利用干涉原理的典型光学系统——马赫-曾德尔电光系数干涉测量系统.首先,结合光学干涉原理和晶体材料的二次电光效应,进行了详细的理论推导,证明了测量方法的正确性和可行性.之后,以钽铌酸钾钠(KNTN)晶体作为研究对象,在实验中测量得到了其二次电光系数s11为2.28×10-15 m2·V-2.在此过程中,通过对马赫-曾德尔光学干涉测量系统的理论剖析与实际应用,相信可以帮助同学们更深入地理解和掌握光学干涉、晶体折射率及其电光效应的本质与原理.