基于静电纺丝纤维的固相萃取和固相微萃取技术在食品安全分析中的研究进展

食品安全分析技术发展对提升食品安全监管能力、确保食品安全具有重要的支撑。近年来,固相萃取和固相微萃取方法在低浓度、复杂基质的食品安全分析领域发挥着重要作用。静电纺丝作为一种纳米材料制备方法,具有操作简便、条件温和、制备高效、易于工业化生产等特征,在新材料研发领域备受关注。近年,以静电纺丝材料为固相萃取和固相微萃取吸附剂的研究取得了较多新的进展,也开始应用于食品安全分析领域。本文总结了食品安全分析领域中基于静电纺丝纤维的固相萃取和固相微萃取技术的研究及应用进展,讨论了现有研究中静电纺丝材料在吸附剂中的应用及相关前处理方法的优势,以期为以静电纺丝纤维为吸附剂的固相萃取和固相微萃取技术在食品安全分析领域的进一步研究提供参考。     

磁性固相萃取技术在邻苯二甲酸酯检测中的应用进展

随着塑料制品的广泛使用，改善其性能的增塑剂，如邻苯二甲酸酯引起的安全问题也日益受到关注。在增塑剂残留检测中，灵敏、简单、快速的前处理技术是至关重要的一步，本文简单介绍了磁性固相萃取技术的基本原理和磁性固相萃取吸附剂的制备修饰，详细综述了功能化修饰磁性固相萃取吸附剂在邻苯二甲酸酯分析的国内外研究成果。其中包括基于有机材料、无机材料、其它材料功能化修饰磁性固相萃取吸附剂。旨在阐明各种功能化修饰磁性固相萃取吸附剂在邻苯二甲酸酯检测中具体应用方法，比较分析了各种功能化修饰方法的优缺点。最后展望了磁性固相萃取技术在邻苯二甲酸酯测定的发展趋势。     

碳纳米管固相萃取金属离子研究

碳纳米管具有高的比表面积,良好的化学性能,机械性能和热稳定性,因而被用作固相萃取的吸附剂吸附金属离子。综述了碳纳米管作为固相萃取材料富集金属离子的研究成果,介绍碳纳米管的结构特性,重点分析其作为固相萃取填料在金属离子吸附方面的机理及应用,展望了碳纳米管在固相萃取技术中的发展趋势。     

新型固相萃取吸附技术在食品分析中的应用

本文基于固相萃取吸附剂,综述了多种固相萃取小柱联用、分子印迹固相萃取、碳纳米管固相萃取和磁固相萃取等技术在食品分析前处理中的应用。研究表明,这些新型吸附剂相对于传统的固相萃取吸附剂具有分离速度快、效率高、环境友好、检出限低等优点。同时分别阐述了这4种萃取技术在食品检测领域的局限性。进一步指出开发高效快速分离目标物的吸附剂是固相萃取技术在食品检测行业的发展趋势。     

碳纳米管固相萃取在食品安全检测中的应用进展

跟一般的吸附材料相比,碳纳米管具有比表面积大、化学性质稳定、机械稳定性和热稳定性好以及吸附能力强的优点,且固相萃取操作简便、萃取时间短、有机溶剂使用量少,碳纳米管作为吸附剂结合固相萃取用于食品样品的前处理显现出较好的效果。本文介绍了碳纳米管的功能化修饰及其吸附特性,主要综述了碳纳米管固相萃取在食品重金属、农药、兽药和有机污染物检测中的应用概况,并对碳纳米管固相萃取的应用现状及前景作了展望。     

磁性功能材料应用于食品中有毒有害物质检测的研究进展

磁性固相萃取是近年来不断发展的一种样品前处理技术,而磁性功能材料作为磁性固相萃取的吸附剂,由于其独特的物理和化学特性引起广泛关注。本文总结分析了2010年以来磁性功能材料在食品中农药、兽药、合成色素、及其他有毒有害物质检测应用方面的研究进展,以期为食品安全检测新技术的推广应用提供参考。     

固相萃取在食品农药残留检测中的应用

固相萃取(Solid-Phase Extraction,简称SPE),是近年来发展起来的一种样品预处理技术。固相萃取就是利用固体吸附剂将液体样品中的目标化合物吸附,与样品的基体和干扰化合物分离,然后再用洗脱液洗脱或加热解吸附,达到分离和富集目标化合物的目的。固相萃取作为样品前处理技术,在实验室中得到了越来越广泛的应用。     

石墨烯固相萃取-LC-MS/MS检测甲硫威残留条件优化

使用石墨烯作为固相萃取吸附剂,对影响甲硫威前处理及检测的固相萃取条件及仪器条件进行了优化,包括石墨烯质量、离子强度、洗脱试剂、洗脱体积,以及质谱条件、液相条件。结果表明,固相萃取时,使用15mg石墨烯,无需调节离子强度,采用3m L乙腈洗脱;检测时,采用多反应监测模式,使用甲醇-0.1%甲酸水作为流动相在梯度洗脱的条件下能够得到满意的结果。     

离子液体及聚离子液体在基于固相萃取技术的食品安全分析中的应用

由于食品样品多样性和复杂性,样品前处理成为食品安全分析的关键。固相萃取技术是食品安全分析中富集痕量组分、分离干扰物质的重要前处理方法。将具有特殊物理化学性质的离子液体及聚离子液体,应用于固相微萃取、基质固相分散萃取、分子印迹固相萃取、整体柱固相萃取等固相萃取技术中,改善了固相吸附剂性能,提高了固相萃取效率,实现了对食品样本中重金属离子、农兽药残留、违规或超标添加剂等的高效富集、分离,合并其他分离分析方法,达到了准确测定这些物质的含量的目的。离子液体及聚离子液体在食品分析的前处理中的应用将越来越广泛。     

多壁碳纳米管磁性固相萃取气相色谱质谱法测定茶叶中的8种农药残留

建立了磁性固相萃取-气相色谱质谱法测定茶叶中8种农药的检测方法,利用乙腈对样品进行提取,使用磁性吸附剂MWCNTs-Fe3O4富集和净化茶叶初提液中的农药,气相色谱-质谱定量检测.对影响磁性固相萃取的条件进行了优化,主要包括萃取剂、吸附剂用量、吸附时间、洗脱剂、洗脱时间等.结果 表明,8种农药在各自质量浓度范围内线性关...     

Adsorption of polar and nonpolar organic chemicals to carbon nanotubes

Understanding adsorptive interactions between organic contaminants and carbon nanotubes is critical to both the environmental application of carbon nanotubes as special adsorbents and the assessment of the potential impact of carbon nanotubes on the fate and transport of organic contaminants in the environment. The adsorption of organic compounds with varied physical-chemical properties (hydrophobicity, polarity, electron polarizability, and size) to one single-walled carbon nanotube (SWNT) and two multiwalled carbon nanotubes (MWNTs) was evaluated. For a given carbon nanotube, the adsorption affinity correlated poorly with hydrophobicity but increased in the order of nonpolar aliphatic < nonpolar aromatics < nitroaromatics, and within the group of nitroaromatics, the adsorption affinity increased with the number of nitrofunctional groups. We propose that the strong adsorptive interaction between carbon nanotubes and nitroaromatics was due to the pi-pi electron-donor-acceptor (EDA) interaction between nitroaromatic molecules (electron acceptors) and the highly polarizable graphene sheets (electron donors) of carbon nanotubes. Additionally, we attribute the stronger adsorption of nonpolar aromatics compared to that of nonpolar aliphatics to the pi-electron coupling between the flat surfaces of both aromatic molecules and carbon nanotubes. For tetrachlorobenzene, the bulkiest adsorbate, adsorption affinity (on a unit surface area basis) to the SWNT was much stronger than to the two MWNTs, indicating a probable molecular sieving effect.     

Adsorption of hydroxyl- and amino-substituted aromatics to carbon nanotubes

The combined effects of hydroxyl/amino functional groups of aromatics and surface O-containing groups of carbon nanotubes on adsorption were evaluated. When normalized for hydrophobicity, 2,4-dichlorophenol and 2-naphthol exhibited a greater adsorptive affinity to carbon nanotubes and graphite (a model adsorbent without the surface O functionality) than structurally similar 1,3-dichlorobenzene and naphthalene, respectively, and 1-naphthylamine exhibited a much greater adsorptive affinity than all other compounds. Results of the pH-dependency experiments further indicated that the hydroxy/amino functional groups of the adsorbates and the surface properties of the adsorbents played a combinational role in determining the significance of the nonhydrophobic adsorptive interactions. We propose that the strong adsorptive interaction between hydroxyl-substituted aromatics and carbon nanotubes/graphite was mainly due to the electron-donating effect of the hydroxyl group, which caused a strong electron-donor-acceptor (EDA) interaction between the adsorbates and the pi-electron-depleted regions on the graphene surfaces of carbon nanotubes or graphite. In addition to the EDA interaction, Lewis acid-base interaction was likely an extra important mechanism contributing to the strong adsorption of 1-naphthylamine, especially on the O-functionality-abundant carbon nanotubes. The findings of the present study might have significant implications for selective removal of environmental contaminants with carbon nanotubes.     

Efficient adsorption of super greenhouse gas (tetrafluoromethane) in carbon nanotubes

Light membranes composed of single-walled carbon nanotubes (SWNTs) can serve as efficient nanoscale vessels for encapsulation of tetrafluoromethane at 300 K and operating external pressure of 1 bar. We use grand canonical Monte Carlo simulation for modeling of CF4 encapsulation at 300 K and pressures up to 2 bar. We find that the amount of adsorbed CF4 strongly depends on the pore size in nanotubes; at 1 bar the most efficient nanotubes for volumetric storage have size R = 0.68 nm. This size corresponds to the (10,10) armchair nanotubes produced nowadays in large quantities. For mass storage (i.e., weight %) the most efficient nanotubes have size R = 1.02 nm corresponding to (15,15) armchair nanotubes. They are better adsorbents than currently used activated carbons and zeolites, reaching approximately equal to 2.4 mol kg(-1) of CF4, whereas, the best activated carbon Carbosieve G molecular sieve can adsorb 1.7 mol kg(-1) of CF4 at 300 K and 1 bar. We demonstrate that the high enthalpy of adsorption cannot be used as an only measure of storage efficiency. The optimal balance between the binding energy (i.e., enthalpy of adsorption) and space available for the accommodation of molecules (i.e., presence of inaccessible pore volume) is a key for encapsulation of van der Walls molecules. Our systematic computational study gives the clear direction in the timely problem of control emission of CF4 and other perfluorocarbons into atmosphere.     

Caged multiwalled carbon nanotubes as the adsorbents for affinity-based elimination of ionic dyes

Multiwalled carbon nanotubes (MWCNTs) were used as the active elements for the first time for affinity-based elimination of ionic dyes. MWCNTs were encapsulated in cross-linked alginate (ALG) microvesicles using Ba2+ as the bridging ion. The Ba2+-alginate matrix constitutes a cage which holds the physically trapped MWCNTs. The cage carries negative charges on its surface. The cage restricts the access of anions of large molecular weight, such as humic acids, because of electrostatic repulsion. The cage also restricts the access of colloids of large size, because of size exclusion. Ionic dyes partition into the cage and then are captured by MWCNTs probably on the basis of van der Waals interactions occurring between the hexagonally arrayed carbon atoms in the graphite sheet of MWCNTs and the aromatic backbones of the dyes. As a result of these interactions the target species, namely, the ionic dyes, are eliminated efficiently by the MWCNTs of Ba2+-ALG/MWCNT composite adsorbents. The adsorptive capacities for elimination of acridine orange, ethidium bromide, eosin bluish, and orange G (the model species used for this study) were found as high as 0.44, 0.43, 0.33, and 0.31 micromol, respectively, for 1.0 mg of the caged MWCNTs. Adsorptive experiments with carbon nanofibers and activated carbons as the adsorbents were also performed. The MWCNT-based adsorbents provided the best capability for the affinity-based elimination of these targeted species. Biocompatibility experiments performed in vitro and in vivo provided promising results, suggesting potential applications of the caged MWCNTs in in situ environmental remediation.     

木质素基吸附剂的研究进展

木质素是具有三维无定型结构的天然高分子聚合物,以木质素为原料制备的木质素基吸附剂是木质素增值利用的重要途径之一.通过改性、复合等手段制备的生物炭、微球、凝胶等类型木素基吸附剂在工业废水处理方面有着广泛的应用.本文综述了木质素纤维化处理、制备活性炭、磁化处理等未改性木质素基吸附剂,胺化、磺化、酯化、接枝、共聚等手段处理的...     

真菌毒素吸附剂开发及吸附效果评价方法研究进展

国家高度重视节粮减损工作,强调采取多项措施降低粮食损失。真菌毒素污染造成了粮油和饲料资源的损失,并严重威胁人类和畜禽健康。采用物理、化学和生物法可以脱除真菌毒素,提高饲料资源的利用价值,其中吸附剂吸附是通过吸附剂和真菌毒素稳定结合成复合体的脱毒方式。对传统吸附剂的多重改性、新型吸附材料的开发显著提升了脱毒效果。综述真菌毒素吸附剂的种类及其在粮油饲料中使用效果的评价方法,简要介绍了铝硅酸盐类、碳材料、有机高分子、生物吸附剂和新型吸附材料等真菌毒素吸附剂的改性方法,重点介绍了体外法、人工胃肠液体外模拟和动物试验在真菌毒素吸附剂有效性和安全性评价中的应用,可以为新型高效真菌毒素吸附剂的开发、科学应用及其吸附机制解析提供参考。     

Fundamental adsorption characteristics of carbonaceous adsorbents for 1,2,3,4-tetrachlorobenzene in a model gas of an incineration plant

Carbonaceous adsorbents such as activated carbon have been used to reduce the emission of organic pollutants from incineration plants. However, with this method, the amount and type of adsorbent to be used are based only on empirical results, which may lead to overuse of the adsorbents. The fundamental adsorption characteristics of several kinds of activated carbon, activated coke, and carbide wood were examined using 1 ,2,3,4-tetrachlorobenzene as an adsorbate. The removal performance and various equilibrium adsorption characteristics of these adsorbents were analyzed using laboratory-scale adsorption equipment. The equilibrium adsorption amount increased by a factor of 1.9-3.2 at 150 degrees C compared with that at 190 degrees C. The effect of the moisture content on adsorption capacity was relatively small in comparison with that of the temperature. The micropore volume for pore diameters of 2 nm or less was the most important factor governing the adsorption capacity for all adsorbents. Activated carbon showed superior adsorption ability compared to activated coke and carbide wood, although all adsorbents were sufficient for practical use.     

Selection of low swelling materials for protein adsorption from white wines

Summary The protein adsorption capacity of different materials was evaluated to assess their potential efficacy as alternative adsorbents for the removal of proteins from wines, with the purpose of finding suitable low-swelling materials that could be used in a percolated bed. The adsorbents tested were thermally treated sodium bentonite, low-swelling adsorbing clays, ion exchange resins and other protein adsorbents (silica gel, hydroxyapatite and alumina). The materials were evaluated by analysing both the capacity to stabilize untreated white wines, according to a heat test, and by characterizing the adsorption isotherms of bovine serum albumin (BSA) in a model wine (water, ethanol and K-bitartrate). Breakthrough curves in a packed bed were determined experimentally for some materials, showing the influence of the adsorption isotherm shape. Some ion-exchange resins showed a favourable behaviour and have good potential as alternative adsorbents.     

Comparative study of soybean oil refining using rice hull silicate and commercial adsorbents

To obtain an edible grade of soybean oil, impurity removal processes are important steps in refining. To remove coloring compounds and free fatty acids, commercial adsorbents (silica gel, activated carbon, aluminum oxide, alumina silicate, acid clay, and zeolite) and rice hull silicate (RHS) were evaluated with respect to their adsorption removal efficiencies for lutein. Various doses of commercial adsorbents and RHS were individually added to degummed soybean oil to remove lutein. The commercial adsorbents and RHS substantially reduced lutein amounts in degummed soybean oil. Silica gel was the most effective adsorbent, followed by acid clay, and RHS. Treatments with adsorbents also reduced the residual free fatty acid (FFA) content. Aluminum oxide was the most effective in removal of FFA (approximately 40% reduction). RHS and rice hull ash (RHA) showed similar deacidification effects. RHS can be used as an alternative bleaching agent as it was effective in reducing the residual FFA content in soybean oil.