共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
Dr. C. André Ohlin 《化学:亚洲杂志》2012,7(2):262-270
Mass spectrometry both complements other analytical techniques and allows for types of analyses and experiments not possible with common analytical methods, such as NMR, IR, and UV/Vis spectroscopy. Electrospray constitutes one of the mildest forms of ionization, making it the preferred method for the analysis of large fragile or reactive ions. There is particular promise for mass spectrometry in aiding the characterization of polyoxometalates and their solutions, but caution must be taken in designing the experiments in order to yield reliable data and to avoid the temptation of over‐interpreting the relevance of gas‐phase data to solution chemistry. 相似文献
4.
电喷雾质谱对洗发水中多种表面活性剂的快速分析 总被引:1,自引:0,他引:1
利用电喷雾离子化质谱技术(ESIMS)快速鉴定了洗发水中的常用表面活性剂。在流动注射进样方式下,鉴定出所测试洗发水中含有2种主要表面活性剂:烷基单乙醇酰胺(CMEA)和脂肪醇聚氧乙烯十二烷基醚硫酸钠(SLES·nEO)。进一步通过高效液相色谱与质谱联用(HPLC—MS)利用ESI^+和ESI^-之间的切换完成对不同类型表面活性剂的定量检测,测定出该洗发水中CMEA的使用量为1.198%(质量分数),与实际添加量1.2%非常吻合。运用HPLC—MS对SLES·nEO在洗发水中的种类结构进行了鉴定。 相似文献
5.
采用自行研制的电喷雾萃取电离源(EESI)与LTQ-XL质谱仪耦合,并结合主成分分析(PCA)和聚类分析(CA),建立了一种能在无需样品预处理的条件下直接、快速、准确鉴别茅台等八种掺假白酒(混掺水和工业酒精,且通过酒精计调控掺假酒的酒精度与真酒保持一致)的新方法. 同时,利用串联质谱能够对目标组分进行准确鉴定. 研究结果表明,EESI-LTQ-MS检测单个样品的时间小于1 min,且重现性好,PCA区分正确率高达96.5%. 通过设置未知样分析进一步验证了该方法的可行性. 此外,还结合单光子电离飞行时间质谱法(SPI-TOF-MS)对检测谱图进行对比分析. 阐述了EESI和SPI两种电离技术在挥发性有机物分析上具有各自的优势,且两种检测手段具有互补的特点. 为市场上酒类饮品真假的快速鉴别及品质鉴定建立了一个综合的分析方法,对于快速筛选伪劣酒类产品具有非常重要的应用价值. 相似文献
6.
Dr. Ulrike Warzok Lisa K. Mahnke Prof. Dr. Wolfgang Bensch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(6):1405-1419
Polyoxometalates (POMs) are an intriguing class of compounds due to their tremendous structural variety and the wide spectrum of resulting properties, which make them interesting for applications in fields such as catalysis, material science or nanotechnology. Their ability to form large supramolecular architectures by self-assembly offers an entry to complex, functional systems. After an introduction into the structure and synthesis of POMs of the early transition metals, recently discovered water-soluble antimonato polyoxovanadates (Sb-POVs) and the investigation of their chemical reactivity are discussed. Electrospray ionization mass spectrometry (ESI-MS) is presented as an analytical technique suitable to investigate the structure of complex POM assemblies in solution and to probe the underlying reactivity and formation mechanisms. This Minireview highlights the first studies on the soluble Sb-POVs and how the knowledge of their reactivity obtained by ESI-MS has fostered the syntheses of numerous novel Sb-POV compounds. 相似文献
7.
采用内部萃取电喷雾电离质谱(iEESI-MS)技术,以甲醇作为萃取溶剂,无需样品预处理,在优化条件下分别对牛油果果肉和果皮中化学成分进行快速直接鉴定,并考察了不同成熟度牛油果果肉中化学成分的差异.实验结果表明,在负离子检测模式下,从果肉中鉴定出棕榈酸、硬脂酸、棕榈油酸、油酸和亚麻酸等12种有效营养成分,从果皮中鉴定出儿茶素、绿原酸等11种营养成分.利用正交偏最小二乘判别分析法(OPLS-DA)对不同成熟度的牛油果果肉的iEESI-MS指纹谱图数据进行分析发现,此方法能够有效判别不同成熟程度的牛油果且5种化学成分差异显著.本方法无需样品预处理、样品耗量少、分析速度快(单个样品检测时间小于1 min)且操作简便,为植物有效营养成分和医用价值的开发提供了一种快速质谱分析新方法. 相似文献
8.
基于常压质谱的直接、快速、无需样品预处理检测的优势,该文拓展了其在药物质检领域的应用。采用自行搭建的解析电喷雾(DESI)装置,对常用感冒药对乙酰氨基酚片进行快速质谱检测,无需样品预处理,直接获得药片中有效成分的分子结构信息。为克服基质差异对定量分析的影响,以淀粉为基质构建对乙酰氨基酚模拟药片,在优化的基础上进行定量实验。针对实际药片中高浓度对乙酰氨基酚检测的需要,研究了其在较高浓度范围的定量关系,结果显示,方法对0.35~4.52 mg/mm2范围内的对乙酰氨基酚具有较好的线性关系(r2=0.998 2),定量下限为1.903 ng/mm2,检出限为0.237 ng/mm2,加标回收率为102%~114%。对3种市售的对乙酰氨基酚片进行直接检测,与厂家提供的标准数据相比,相对标准偏差(RSD)为7.2%~12%,表明方法具有较好准确度。该工作很好地证明了DESI-MS在药品快检中的优势,从而为药品质检提供了潜在的高效、可靠的检测手段。 相似文献
9.
Christian Hinderling Peter Chen 《Angewandte Chemie (International ed. in English)》1999,38(15):2253-2256
The simultaneous screening of catalysts according to their propensity for catalyzing the polymerization of ethylene (see scheme) can be achieved with the help of electrospray ionization tandem mass spectrometry. A small (eight catalysts) library of PdII complexes synthesized simultaneously in a one-pot reaction has demonstrated the efficiency of this new screening technique. This method could be widened to libraries of other olefin polymerization catalysts. 相似文献
10.
电喷雾质谱的非共价键蛋白质复合物研究 总被引:1,自引:0,他引:1
电喷雾质谱(ESI-MS)已经成为检测和研究生物分子弱相互作用,即非共价键作用的一个重要分析手段.ESI-MS除了具有快速、灵敏、专属的特点以外,还有能够直接得出复合物的分子量和化学计量比的优点.本文通过蛋白质与蛋白质、配体、金属离子的非共价复合物的例子阐述了ESI-MS技术的主要特性,综述了ESI-MS在非共价键蛋白质复合物方面的早期和近期应用研究成果.引用文献34篇. 相似文献
11.
Rapid Quantification of Efavirenz in Human Plasma by Electrospray Ionization Tandem Mass Spectrometry 下载免费PDF全文
We report a rapid and sensitive method for detecting efavirenz in human plasma by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Detection of efavirenz in human plasma samples was confirmed by acquiring MS/MS of protonated efavirenz at m/z 316.5 to yield the characteristic fragment ions at m/z 298, 274, 272, 251, 246, 237, 232, 203 and 168, respectively. This approach provided good linearity for the quantification of efavirenz (R2 = ~0.9989), with good precision (RSD >10%) and limit of detection (0.20 nM). This method can be widely applied for precise quantitative analysis of a variety of drugs in clinical samples. 相似文献
12.
在不需要样品制备、预处理的前提下,将电喷雾解吸电离质谱法用于岩石、纸张、布料、皮革、塑料、橡胶等不同表面上黑索今的直接快速检测.在优化试验条件下,用甲醇-乙酸(98+2)混合溶液作为喷雾溶剂,获得质荷比(m/z)223的黑索今准分子离子峰,并且通过串联质谱(MS/MS)分析确定了黑索今碎片特征峰m/z 177.不同物质表面上黑索今的检出限(3a)均小于17.0 pg·cm-1. 相似文献
13.
Electrospray ionization mass spectrometry (ESI-MS) has made possible many new and important advances in analytical chemistry by combining mass analysis with the ability to generate gas-phase ions from labile polar and ionic species in solution. 相似文献
14.
J. Stuart Grossert Lisandra Cubero Herrera Louis Ramaley Jeremy E. Melanson 《Journal of the American Society for Mass Spectrometry》2014,25(8):1421-1440
Analysis of triacylglycerols (TAGs), found as complex mixtures in living organisms, is typically accomplished using liquid chromatography, often coupled to mass spectrometry. TAGs, weak bases not protonated using electrospray ionization, are usually ionized by adduct formation with a cation, including those present in the solvent (e.g., Na+). There are relatively few reports on the binding of TAGs with cations or on the mechanisms by which cationized TAGs fragment. This work examines binding efficiencies, determined by mass spectrometry and computations, for the complexation of TAGs to a range of cations (Na+, Li+, K+, Ag+, NH4 +). While most cations bind to oxygen, Ag+ binding to unsaturation in the acid side chains is significant. The importance of dimer formation, [2TAG + M]+ was demonstrated using several different types of mass spectrometers. From breakdown curves, it became apparent that two or three acid side chains must be attached to glycerol for strong cationization. Possible mechanisms for fragmentation of lithiated TAGs were modeled by computations on tripropionylglycerol. Viable pathways were found for losses of neutral acids and lithium salts of acids from different positions on the glycerol moiety. Novel lactone structures were proposed for the loss of a neutral acid from one position of the glycerol moiety. These were studied further using triple-stage mass spectrometry (MS3). These lactones can account for all the major product ions in the MS3 spectra in both this work and the literature, which should allow for new insights into the challenging analytical methods needed for naturally occurring TAGs. Figure
? 相似文献
15.
选择芦笋(Asparagus Officinalis L)新鲜茎块和两种干燥茎块为代表性植物组织样品,建立了一种直接检测芦笋中多种化学成分的内部萃取电喷雾电离质谱(iEESI-MS)分析方法。在正离子检测模式下,选择甲醇(CH3OH)作萃取溶剂,在无需样品预处理的条件下对芦笋组织样品进行直接质谱分析,获得了组织样品在m/z 50~1000范围内的化学指纹谱图,并通过目标离子的碰撞诱导解离(CID)实验,鉴定了对药物和自然产品研发具有重要意义的糖类、氨基酸、生物碱以及芦丁等多种代表性的营养成分。 本方法具有无需样品预处理、样品耗量少、操作简便、分析速度快(单个样品的分析时间少于1 min)等优点,为食源性植物组织样品的快速分析提供了一种质谱分析新方法。 相似文献
16.
17.
Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studed: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. 相似文献
18.
19.
The site of protonation in a molecule can greatly affect the fragments observed in product ion MS/MS spectra. In electrospray
positive ionization mass spectra, protonation usually occurs predominantly on the most basic site on the molecule to produce
the thermodynamically favored protonated species. However, the literature is unclear whether liquid phase or gas phase thermodynamics
has the greater influence. This paper describes the protonation and fragmentation behavior of crizotinib and two of its impurities.
Crizotinib has two possible protonation sites, a pyridine nitrogen and a secondary amine, piperidine nitrogen; the former is the favored site in the gas phase and the latter the more favored site in the liquid phase. The impurities
contain alkyl substitution on the piperidine nitrogen, producing tertiary amine species. Literature precedence suggests that
in the liquid phase, the piperidine nitrogen is still the most basic site but, in the gas phase, the pyridine nitrogen and
the piperidine nitrogen have very similar basicities. Fragmentation data for the three molecules suggest that the secondary
and tertiary amines protonate preferentially and almost exclusively on different sites. We propose that the secondary amine
protonates on the piperidine nitrogen (influenced by solution thermodynamics) and the two tertiary amine structures protonate
on the pyridine nitrogen because of steric hindrance at the most basic site of the molecule, allowing kinetic control of the
protonation process. 相似文献