碳点在抗生素分析检测中的应用

抗生素的过度使用对环境造成了极大破坏,对其进行监测控制刻不容缓。常用的分析检测技术,如高效液相色谱(HPLC)、气相色谱(GC)、高效液相色谱-串联质谱(HPLC-MS/MS)等具有高效快速、重现性好、可自动化操作等优点。但对环境样品中抗生素的检测存在样品前处理过程繁琐、检测灵敏度低、实验成本高等问题。结合现有的检测技术发展新型材料,对提高抗生素的检测灵敏度具有重要意义。碳点(CDs)是一种尺寸介于0~10 nm之间的新型纳米材料,具有小尺寸效应、优异的电学和光学性质、良好的生物相容性等优点,已被广泛应用于环境样品中抗生素的检测。该综述对近5年CDs与传感器、色谱分析技术结合检测抗生素的应用进行了总结,并对其发展前景进行了展望。该文总结了CDs与分子印迹传感器、适配体传感器、电化学发光传感器、荧光传感器及电化学传感器相结合,及其在抗生素检测中的应用;对涉及的比率型传感器、阵列传感器等先进分析方法进行了举例评述;对CDs作为色谱固定相分离抗生素进行了阐述。文献表明,CDs结合传感器检测抗生素可有效提高检测灵敏度,但对复杂环境样品中抗生素的检测还面临着构建高选择性传感器、开发新型材料及数据处理等方面的挑战;目前,CDs作为色谱固定相对抗生素的材料分离,仍处于初步研究阶段,分离机理尚不明确,有待进一步深入研究。总之,CDs在环境样品中抗生素的检测方面仍面临一系列问题,随着人们对CDs的深入研究以及各种分析检测技术的不断发展,CDs将会在抗生素等环境污染物的检测中发挥重要作用。     

复杂样品痕量极性小分子化合物的样品前处理及分析方法研究进展

核苷、胺、氨基酸等极性小分子化合物是生物、食品、环境等领域重要的研究对象,但各种复杂基体中痕量极性小分子的分离分析需要高效的前处理介质和技术以及快速灵敏的分析方法。本文综述了硅胶材料、有机聚合物、炭材料和硼酸材料等样品前处理分离介质及反相液相色谱、亲水作用色谱等分析方法在复杂样品痕量极性小分子化合物分析中的应用,并展望了其发展趋势。     

涡流色谱技术在生物样品分析中的应用

生物样品的复杂性使其在进行分析测定前必须经过处理。传统的样品前处理方法(如液-液萃取、固相萃取等)耗时长且操作繁琐。涡流色谱作为在线萃取技术,可以实现生物样品直接进样,减少了样品处理步骤,有效富集纯化了分析物,是一种高通量、高选择性的生物样品前处理方法。为此,本文介绍了涡流色谱技术的原理及优势,并总结了不同涡流柱的特点及其在生物样品分析领域中的应用情况。     

功能化磁性纳米材料在样品前处理中的应用研究进展

随着分析化学所面临的样品性质的复杂程度越来越高,被检测物质的浓度要求越来越低,在色谱及质谱分析前进行准确、高效的样品前处理过程就显得尤为重要。磁性固相萃取法由于其合成方法简单、易于分离、萃取效率高等优点,被认为是一种高效的样品预处理方法。Fe₃O₄磁性纳米材料由于分离速度快,分散性、生物相容性好等特点,近年来被广泛用于分离分析等各个领域。为了提高Fe₃O₄磁性纳米材料的物理和化学的稳定性,使其具备更高效的吸附分离能力,需要对其进行功能化的修饰。本文综述了近年来由碳基纳米材料、分子印迹聚合物、离子液体、硼酸亲和配体、金属有机骨架、共价有机骨架、量子点、金属氧化物等功能化磁性纳米材料的制备及其在生物、环境污染物、食品样品等样品前处理中的应用,并对这一领域发展进行了展望。     

环境样品中砷、硒形态分析研究进展

综述了近年来环境样品中砷、硒形态分析的研究进展,主要内容包括样品的前处理技术、分离技术、检测技术。前处理技术主要是用各种提取液采用各种方式提取样品中的砷、硒形态,分离技术主要有高效液相色谱分离、气相色谱分离、毛细管电泳分离等,检测技术主要有原子吸收光谱法、原子发射光谱法、原子荧光光谱法、电感耦合等离子体质谱法等。最后对其研究前景进行了展望。     

生物相容性分离介质在样品前处理中的应用

生物样品基体复杂,蛋白质等生物大分子的干扰给样品前处理带来很大的困难.近年来,生物相容性分离介质在样品前处理中的应用特别引人注目.本文综述了生物相容性分离介质及其在固相萃取、固相微萃取、微透析样品前处理中应用的进展.     

基于共价－有机骨架固定相的色谱分离应用研究进展

共价－有机骨架材料（COFs）是一类由轻质元素通过共价键形成的多孔材料,具有比表面积大、稳定性好、孔径可调、功能多样、结构可修饰等特点,在分析化学领域如样品前处理和色谱分离等方面显示出了良好的应用前景。其中COFs作为新颖色谱固定相在高效液相色谱、气相色谱和毛细管电色谱分离应用研究也逐渐引起了人们的关注。色谱分离所用COFs均具有良好的化学稳定性,但比表面积、孔径和性质各异,适用于分离不同类型的目标物如有机小分子、同分异构体和手性化合物等。该文综述了近年来以COFs为固定相的色谱分离应用研究进展,包括基于COFs的色谱固定相/色谱柱的制备及其色谱分离应用,并对其进行了展望。     

二维液相色谱在药物和毒物分析中的应用进展

生物样品中药物、毒物及内源性物质的定性与定量分析在生命科学和药物研发中发挥重要作用。生物样品的基质复杂,干扰物多,待测物浓度与内源性物质相比明显偏低,且样品取样量少,因此要求生物分析方法的特异性强、灵敏度高、重现性好。二维液相色谱技术具有峰容量大、显著降低复杂样品的基质效应和残留现象,及可以实现样品分析的自动化等特点,已成为生物样品分离分析的有力工具,在环境、食品和药物分析中得到广泛应用。本文在简要介绍了二维液相色谱原理装置基础上,对其在生物样品中药物、毒物和内源性物质分析中的应用进展进行了综述。     

分子印迹技术在样品前处理中的应用

分子印迹聚合物具有选择性高、稳定性好及制备简单的特点,可用于生物、医药、环境样品等复杂基体中痕量分析物的高选择性分离与富集,因此在样品前处理中的应用特别引人关注.本文介绍了分子印迹技术的基本原理,综述了分子印迹技术在样品前处理中应用的研究进展.     

色谱分析中样品前处理技术的发展动态

作为现代分析领域的重要手段之一,色谱可用于食品、环境、生物等复杂样品的定性与定量分析。而样品前处理是获得理想色谱分析结果的必要前提,它可有效消除基质干扰、浓缩目标分析物、改善分离效能以及延长色谱仪器使用寿命。本文主要依据2020年4-5月Anal Chem新发表和在线录用的有关论文,讨论色谱分析中涉及样品前处理技术方面的最新发展动态。     

Monosubstituted positively charged cyclodextrins: Synthesis and applications in chiral separation

Several series of novel structurally well-defined positively charged CDs, applicable to alpha-, beta- and gamma-CDs for chiral separation using CE and chromatographic techniques have been developed. The chiral resolution capabilities of different series CDs towards amino acids and anionic analytes in CE are systematically investigated by considering all separation parameters including CD type, alkyl chain length of the cations attached to the CD rim, CD concentration, buffer pH, separation temperature and organic solvent. Typical results are demonstrated in the context. Examples of chiral separation with HPLC and supercritical fluid chromatography are first demonstrated by using coated chiral stationary phases (CSPs). Optimum CD loading content on the coated CSPs was explored in the chiral separation of neutral analytes.     

Analysis of sulthiame in serum by narrow-bore high-performance liquid chromatography. Comparison of direct sample injection with pre-column switching and extrelut extraction.

Two high-performance liquid chromatographic methods for the analysis of sulthiame in serum are described. In the first method direct injection of serum samples onto a 4 x 4 mm I.D. (C18, 25 microns) precolumn in a column-switching device was used. After a purge step, the adsorbed analytes were eluted onto a 250 x 3 mm I.D. (C18, 5 microns) narrow-bore column for chromatographic separation. In the second method the sample pretreatment was an Extrelut extraction with dichloromethane-propanol-2 (95:5). After evaporation of the solvents, the residue was dissolved in methanol. The chromatographic separation was carried out on the same analytical column as used in the column-switching method. Both sample pretreatment methods were compared with respect to their suitability of routine analysis of sera from patients also receiving other antiepileptic drugs.     

金属有机骨架及其复合材料在分离领域中的应用进展

金属有机骨架（MOFs）是一类由无机金属离子与有机配体自组装形成的新型有机-无机杂化多孔材料,因具有比表面积超高、结构多样、热稳定性良好、孔道尺寸和性质可调等优势,在分离领域表现出重要的应用价值。然而,采用传统方法制备的MOFs多为粒径在微米或亚微米尺度的晶体,且颗粒形貌不规则,因此限制了MOFs在样品前处理和色谱固定相等领域的应用和发展。构建基于MOFs的复合材料是弥补MOFs应用缺陷的一项有效措施,有望在保留MOFs优越的分离特性的同时,引入基体材料的特定性能。该文简要综述了近年来MOFs及其复合材料在吸附、样品前处理和色谱固定相等分离领域中的应用进展,并对MOFs在分离科学中的应用前景做出展望。     

Recent innovations in the use of charged cyclodextrins in capillary electrophoresis for chiral separations in pharmaceutical analysis

A review is presented on the use of charged cyclodextrins (CDs) as chiral selectors in capillary electrophoresis (CE) for the separation of analytes in pharmaceutical analysis. An overview is given of theoretical models that have been developed for a better prediction of the enantiomeric resolution and for a better understanding of the separation mechanism. Several types of charged CDs have been used in chiral capillary electrophoretic separation (anionic, cationic, and amphoteric CDs). Especially the anionic CDs seem to be valuable due to the fact that many pharmaceutically interesting compounds can easily be protonated (e.g., amine groups). For that reason several anionic CDs are now commercially available. Cationic and amphoteric CDs are less common in chiral analysis and only a few are commercially available. Attention is paid to the most common synthesis routes and the characterization of the CDs used in chiral capillary electrophoretic separations. The degree of substitution in the synthesized CDs may vary from one manufacturer to another or even from batch to batch, which may have a detrimental effect on the reproducibility and ruggedness of the separation system. In Sections 4, 5, and 6 the applications of anionic, cationic, and amphoteric CDs for the chiral separation in CE are described. Many interesting examples are shown and the influence of important parameters on the enantioselectivity is discussed.     

Capillary gas chromatography separation of pyrethroic acid methyl esters using four acylated cyclodextrin derivatives as chiral stationary phases

Summary Four cyclodextrin derivatives (CDs) were synthesized by substituting 3-OH of 2,6-di-O-pentyl-β-cyclodextrin with four different chain lengths of acyl groups (butyryl, valeryl, heptanoyl, octanoyl). The chromatographic properties of the four CD derivatives as stationary phases of capillary gas chromatography (CGC) were investigated. These CDs exhibit a wide range of application. Not only five pairs of enantiomers of pyrethroic acid methyl esters were separated on the four CDs, but also some other racemic compounds. Among the four CDs, 2,6-di-O-pentyl-3-O-butyryl-β-CD possesses better enantiomer separation abilities to the studied enantiomers of pyrethroic acid methyl esters than the other studied CDs. The extension of chain length of the acyl groups in 3-position of CDs cannot improve the enantiomer separation abilities of the CD derivatives.     

Optimization strategies and modeling of separations of dansyl-amino acids by cyclodextrin-modified capillary electrophoresis.

Presented in this study is an approach to optimize conditions for capillary electrophoresis separations of multianalyte enantiomeric pairs (D- and L-dansyl (Dns)-amino acids) that involves the rational use of combinations of cyclodextrins (CDs) as enantioselective running buffer additives. Migration data is experimentally obtained for a range of concentrations for native CDs used individually and employed to determine inclusion constants for the Dns-amino acids of interest. An expression for the mobility of the amino acids when multiple (two in this work) CDs are present in the running buffer is used to simulate separations for more complex CD systems. A chromatographic response function involving predicted resolution is generated to gauge the quality of these separations. Simplex methods are then employed for the first time to optimize conditions for the separation of amino acid enantiomers. The validity of this approach is demonstrated for separations of five Dns-amino acid enantiomers using gamma- and beta-CDs at various concentrations. Extending the dual-CD approach to other CDs and increasing the number of CDs beyond two should be possible. To this end, preliminary experiments are performed by using several available single-isomer, derivatized CDs (individually) to determine if they have potential for further studies. Although results with these particular derivatized CDs are not encouraging, we did find that molecular mechanics modeling is useful in interpreting those cases in which low inclusion constants possibly contributed to the ineffectiveness of the CDs.     

Influence of the presence of methyl cyclodextrins in high-performance liquid chromatography mobile phases on the separation of beta-carboline alkaloids

The presence of cyclodextrins (CDs) in the mobile phase alters the chromatographic equilibria and induces a secondary chemical equilibrium associated to the chromatographic separation by HPLC. In this study the influence of the presence of CDs in the mobile phase as chemically modified beta-CDs, i.e. 2,3-di-O-methyl-beta-cyclodextrin (DMbeta-CD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TMbeta-CD) on the separation of the alkaloids norharmane, harmane and harmine is described. These beta-carboline alkaloids are chemically and structurally related and their quantitation by RP-HPLC is of interest due to their biological and pharmacological properties. Two stationary phases (methyl-, C(1) and octadecyl-, C(18)) were employed, with methanol:buffered aqueous solution and ethanol:buffered aqueous solution as mobile phases. The role of tert-butyl alcohol as a mobile phase modifier and also as an inclusion complex stabiliser was also considered. The concentrations of DMbeta-CD and TMbeta-CD vary from 0 to 17 mM. The presence of increasing amounts of CDs in the mobile phase reduces the retention factor. The changes observed in the retention factor allow the determination of the alkaloid/CD apparent association constants, whose magnitude is influenced by the chemical and structural properties of the guest molecules but also by the composition of the mobile phase. Assuming a 1:1 stoichiometry for the inclusion complexes, the apparent association constants obtained were higher for norharmane and for both DMbeta-CD and TMbeta-CD. The strength of the complexes is higher for DMbeta-CD than for TMbeta-CD and this behaviour can be explained considering the steric problems associated to the permethylated-beta-CDs. Besides significant differences in the magnitude of the apparent association constants were observed for the two stationary phases employed and thus can be related to the adsorption of CDs on the stationary phase. A significant reduction in the proportion of organic solvent in the mobile phase (50%) without a decrease in the selectivity or resolution of the separation is a favourable consequence of the presence of the CDs in the mobile phase.     

联用技术测定富硒农产品中硒的形态研究进展

硒的营养功能与农产品硒的形态息息相关。联用技术作为元素形态分析的有效方法,近年来受到了人们广泛关注。对用联用技术测定富硒农产品中硒的形态研究现状及进展进行了综述,包括前处理技术、色谱分离技术和定量检测方法等3个方面。     

Emerging materials for sample preparation

This review provides an update on the implementation of emerging materials as sorbents for sample preparation in combination with chromatographic separation. We have focused on recent applications of metal–organic frameworks, layered double hydroxides, porous carbons obtained from polymers or biomass precursors, and silicates (clays and zeolites). The review is directed toward the strategies followed by the authors to engineer suitable supports enabling the application of materials with unconventional size and shape as high‐performance sorbents to explore new boundaries in sample pretreatment in manual or automated modes.