蛋白质组学中基质辅助激光解吸电离的基质研究进展

基质辅助激光解吸电离(MALDI)技术是近年来发展起来的新的质谱离子化技术。本文较为系统地综述了应用于蛋白质组学中的MALDI基质的最新进展以及不同的基质的优缺点及应用范围,并且归纳了其发展趋势。     

以石墨烯为基质的MALDI-TOF MS对有机及药物小分子的检测

以石墨烯为基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF MS)的新型基质,对氨基酸、多胺化合物、雌激素、环磷酰胺、脱氧核糖核苷酸、胞嘧啶β-D-阿糖等一些典型有机小分子、药物小分子及一些有机反应中间体等进行检测分析。实验结果显示,新型二维石墨烯纳米材料可作为MALDI-TOF MS的新型基质替代三氟乙酸(TFA)等传统基质,实现了对有机及药物小分子的高灵敏检测,且分辨率、解吸/电离效率均较传统基质有着显著提升,具有重现性及耐盐性。     

基质中加入少量盐类改善MALDI-TOF MS的谱图信噪比

自20世纪80年代发明基质辅助激光解吸电离(Matrix assisted laser desorption ionization,MALDI)质谱以来,该技术已在生物分子分析方面得到了广泛应用．作为一种离子化方法,MALDI具有灵敏度高,对样品要求低,能耐高浓度盐和缓冲剂等优点．测定过程中使用合适的基质不仅能提高测试灵敏度和分辨率,还能扩增测试样品的种类。     

MALDIMSI在脂质组学研究中的应用

脂质组学概念自2003年被提出以来,其已成为研究生物体、组织或细胞中脂质的结构、功能及代谢途径的一门学科。脂质的种类众多,同时结构非常复杂,脂质的分析充满了困难和挑战。基质辅助激光解吸电离质谱成像(MALDI MSI)分析技术不仅可以进行物质鉴定,而且可对被分析物进行空间分布成像,近年来,该技术广泛地应用于脂质组学的研究。该文介绍了MALDI MSI在脂质组学研究中的样品处理、基质喷涂及应用方面的研究进展,并就目前存在的问题及解决方案进行了探讨,以期扩展MALDI MSI的应用范围。     

常压激光离子源辅助基质的研究进展及其在食品领域的应用

基于激光的电离质谱具有空间分辨率高、样品预处理简单、易于便携化和可实现成像分析等特点.基质辅助的激光离子源质谱可以避免高能量对分子结构的破坏,在生物大分子分析和检测方面获得了广泛应用.传统辅助基质在低分子量范围的干扰较强,极大地限制了常压基质辅助激光离子源的应用,为解决这一问题,一系列基于新型材料的辅助基质被设计和开发...     

激光解吸电离质谱新型液相基质研究

选用包括纳米粒子在内的多种基质化合物,构成了多种不同组成的液相基质.以多肽、蛋白、大环寡糖和有机小分子等数种类型化合物为样品,系统地考察了不同液相基质在基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)分析中的应用情况,探讨了与固体制样方法的异同点.实验结果表明,有些液相基质对多类化合物具有较好的通用性,而有些液相基质对某些特定类型化合物的分析特别有效.     

MIL-101 (Cr)-表面辅助激光解吸电离-质谱法快速检测血样中的芦丁

本文采用金属有机骨架(Metal Organic Frameworks,MOFs)化合物MIL-101(Cr)作为基质辅助激光解吸电离(MALDI)的基质,将其与传统基质进行对比分析黄酮类小分子化合物,可以实现对黄酮类药物小分子的无背景干扰检测,并据此建立了快速检测芦丁的MIL-101 (Cr)-表面辅助激光解吸电离-...     

小分子物质的MALDI分析及质谱成像研究进展

随着基质辅助激光解吸电离质谱(MALDI-MS)的广泛应用,其对小分子物质(LMW compounds)的分析已经成为此领域的一个重要研究方向.由于传统的小分子基质在分析小分子化合物时会在低分子量区域(m/z1000)产生干扰及抑制效应,使MALDI-MS在分析小分子时效果欠佳.为了解决这一问题,许多手段包括低背景的新基质开发以及分析物的衍生化等被提出.本文系统综述了基质辅助激光解吸电离质谱在小分子分析及成像中的方法及应用,并展望了其未来的发展趋势.     

纳米材料辅助负离子激光解吸电离-飞行时间质谱分析小分子研究进展

基质辅助激光解吸电离-飞行时间质谱（MALDI-TOF MS）作为一种软电离质谱技术,目前已被广泛用于蛋白质、多肽、核酸、聚合物等大分子分析。由于传统有机化合物基质在低相对分子质量（小于700 Da）区域的干扰,该技术在小分子物质分析方面受到很大限制。为克服传统有机化合物基质在低相对分子质量区域的干扰,近年来以纳米材料为代表的无机基质材料备受关注。相对传统有机化合物基质或纳米材料正离子模式,基于纳米材料的负离子激光解吸电离（LDI）有效避免了正离子模式下一种化合物会产生多种加合物的问题,具有图谱简单易于解析、灵敏度高、重现性好等优点。该文综述了近5年来纳米材料负离子LDI-TOF MS技术在小分子分析方面的研究进展,以期拓展该技术在小分子分析方面的应用。     

聚甲基丙烯酸甲酯固定化碳纳米管作为MALDI基质的研究

将聚甲基丙烯酸甲酯材料在多壁碳纳米管表面原位聚合, 利用这种修饰的碳纳米管作为基质辅助激光解析离子化(MALDI)的基质, 利用修饰后的碳纳米管可以“溶解”的特性实现了稳定的MALDI离子化, 并且消除了在低质量端的基质噪音. 此类聚合物衍生的碳纳米管具有相对较好的亲水性表面, 可“溶解”在溶剂中. 此方法适用于有机小分子、多肽、聚合物和蛋白质酶解肽段的质谱分析. 实验表明聚甲基丙烯酸甲酯固定化碳纳米管能有效地吸收和传递激光能量, 可与样品充分地分散混合, 质谱检测背景低, 重现性好, 具有较宽的可测质量范围. 此方法在小分子快速检测和蛋白质组学方面有很大的应用前景.     

Different synthetic routes to obtain hydrophilic matrices

The aim of this study was to examine two different synthetic routes for obtaining new hydrophilic matrices either by the modification of a synthetic matrix or by the copolymerization of hydrophilic monomers. First, the acrylic acid‐ethylene glycol dimethacrylate (AAc‐EGDMA) matrix, obtained from suspension with cyclohexane as the diluent at 70 °C after 2 h of reaction, was used as a base to be modified with TRIS(hydroxymethyl)aminomethane (TRIS). Experimental variables affecting the carbodiimide‐mediated amide‐bond development (i.e., the type of carbodiimide, reaction time, pH, and concentration of the matrix in the reaction medium) on the synthetic AAc‐EGDMA matrix with TRIS were studied. Second, the N‐acryloyl‐TRIS(hydroxymethyl)aminomethane‐ethylene glycol dimethacrylate (NAT‐EGDMA) matrix was obtained under the same experimental conditions as reported for AAc‐EGDMA. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 489–497, 2000     

液态RbCl的态密度

给出了在分子动力学模拟基础上Fumi-Tosi势离子液体的正则模式分析方法,用Fumi-Tosi势(包括长程势)代替Lennard-Jones势,并且用等效Coulomb势处理长程Coulomb作用.讨论了Hessian矩阵元的计算方法和Hessian矩阵特征值的计算方法.计算实践表明，取用余误差函数形式的等效库仑势,可以合理地得到Hessian矩阵和态密度.液态RbCl中构型平均态密度的数值结果表明，液态RbCl的态密度表现出与Lennard-Jones液体的态密度相仿的特点.     

Method development for analysis of short- and long-chain perfluorinated acids in solid matrices

In order to help to elucidate the transport and fate of perfluorinated acids (PFAs) in the environment, a reliable and sensitive analytical method has been developed in present study for determination of short- and long-chain PFAs in various solid matrices. The method consisted of solvent extraction of PFAs from solid matrices using sonication, solid phase extraction (SPE) using weak anion exchange (WAX) cartridges, clean-up of SPE eluent with dispersive carbon sorbent and quantitation by high performance liquid chromatography-negative electrospray-tandem mass spectrometry (HPLC-negative ESI-MS/MS). The method detection limits (MDL) and quantitation limits (MQL), which were analyte- and sample-dependent, ranged from 0.02 to 0.06?ng?g^?1 and 0.10 to 0.90?ng?g^?1, respectively. The recoveries of all PFAs were generally good enough for quantitative analysis of these chemicals (57–115%), especially for short-chain (<C8, 80–115%) PFAs excluded in previous studies because methods were not available. The precisions of this method, represented by the percent relative standard deviation (RSD) of spiked measurements, were in a range of 1–19%. In addition, matrix effect did not affect analyte quantification in solid matrices in most cases, and the validated method was successfully applied to analyses of short- and long-chain PFAs in various solid matrices.     

含骨脱细胞基质电纺纤维的成骨性能

通过脱细胞技术制备了猪骨脱细胞基质(DBM),用胃蛋白酶消化DBM使其变为可溶形式,采用静电纺丝技术制备了含有DBM的左旋聚乳酸(PLLA)电纺纤维(PLLA/DBM),并对PLLA/DBM的形貌、亲水性、细胞相容性、成骨性能和体外矿化能力进行评价.研究结果表明,脱细胞处理能够有效去除骨组织中的细胞成分,使DNA含量显著下降.DBM经胃蛋白酶处理后溶于六氟异丙醇(HFIP),可进行静电纺丝,制备的PLLA/DBM[m(PLLA)∶m(DBM)=10∶0,9∶1,7∶3,5∶5]电纺纤维具有良好的亲水性,且无细胞毒性,对骨髓间充质干细胞的黏附及成骨分化有明显的诱导促进作用,体外生物矿化效果优良.     

Very efficient search for protein alignment--VESPA

A novel approach to the problem of protein alignments is described, which in comparison with existing approaches is visibly more efficient. This approach is based on superposition of amino acid adjacency matrices of a pair of proteins, which have been modified to record the sequential order of amino acids. As a result, one obtains simultaneously all segments of the two proteins which are shifted relative to one another by one or more positions in either directions, without need of a prior exhaustive search for an alignment that included unproductive directions and unknown displacement steps.     

Investigation of colloidal graphite as a matrix for matrix‐assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes

The analysis of low molecular weight compounds by matrix‐assisted laser desorption/ionisation mass spectrometry is problematic due to the interference and suppression of analyte ionisation by the matrices typically employed – which are themselves low molecular weight compounds. The application of colloidal graphite is demonstrated here as an easy to use matrix that can promote the ionisation of a wide range of analytes including low molecular weight organic compounds, complex natural products and inorganic complexes. Analyte ionisation with colloidal graphite is compared with traditional organic matrices along with various other sources of graphite (e.g. graphite rods and charcoal pencils). Factors such as ease of application, spectra reproducibility, spot longevity, spot‐to‐spot reproducibility and spot homogeneity (through single spot imaging) are explored. For some analytes, considerable matrix suppression effects are observed resulting in spectra completely devoid of matrix ions. We also report the observation of radical molecular ions [M^–●] in the negative ion mode, particularly with some aromatic analytes. Copyright © 2016 John Wiley & Sons, Ltd.     

定量AES分析中基体效应的迭代修正法

以Shimizu提出的定量AES分析关系为基础,作者提出一种可用于二元和多元合金定量AES分析的迭代方法。通过引入合金的原子序数和原子密度的概念,计算了合金中元素的基体效应修正因子。与其它方法不同的是,本法中基体效应修正因子是合金元素浓度的函数,受到整体组分的影响。通过对文献报道的五种典型单相多晶二元合金Ag-Pd,Ni-Pd,Cr-Fe,Mo-Fe和Ni-Mg的定量分析计算发现,本法的分析精密度优于F因子法、K因子法及改进K因子修正法。