Lipid and Phospholipid Profiling of Biological Samples Using MALDI Fourier Transform Mass Spectrometry

Here we describe a study of the feasibility of lipid and phospholipid (PL) profiling using matrix assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry (FTMS) for two different applications. In this work PL profiles of different mammalian tissues as well as those of whole cell organisms were examined. In particular, comparative analysis of lipid and PL profiles of tissues from mice fed different diets was done and, in another application, MALDI FTMS was used to analyze PL profiles of genetically modified Saccharomyces cerevisiae. Computational sorting of the observed ions was done in order to group the lipid and PL ions from complex MALDI spectra. The PL profiles of liver tissues from mice fed different diets showed a cross correlation coefficient of 0.2580, indicating significant dissimilarity, and revealed more than 30 significantly different peaks at the 99.9% confidence level. Histogram plots derived from the spectra of wild type and genetically modified yeast resulted in a cross correlation coefficient 0.8941 showing greater similarity, but still revealing a number of significantly different peaks. Based on these results, it appears possible to use MALDI FTMS to identify PLs as potential biomarkers for metabolic processes in whole cells and tissues.     

液相色谱及液质联用技术在环境分析中的应用

高效液相色谱（HPLC）是在经典液相色谱法和气相色谱法的基础上发展起来的新型分离分析技术。20世纪80、90年代后,HPLC技术发展迅速,特别是21世纪初,液相色谱与现代质谱的联机技术有了很大的发展,使HPLC的应用前景更为广阔。在全部已知的有机化合物中近80％的有机化合物属于挥发性低,易受热分解或者大分子化合物,适合于高效液相色谱进行分析。本文主要从HPLC分析方法的特点为切入点,介绍液相色谱及液质联用技术在环境分析中的应用。     

Evaluation of a Method for Nitrotyrosine Site Identification and Relative Quantitation Using a Stable Isotope-Labeled Nitrated Spike-In Standard and High Resolution Fourier Transform MS and MS/MS Analysis

The overproduction of reactive oxygen and nitrogen species (ROS and RNS) can have deleterious effects in the cell, including structural and possible activity-altering modifications to proteins. Peroxynitrite is one such RNS that can result in a specific protein modification, nitration of tyrosine residues to form nitrotyrosine, and to date, the identification of nitrotyrosine sites in proteins continues to be a major analytical challenge. We have developed a method by which ¹⁵N-labeled nitrotyrosine groups are generated on peptide or protein standards using stable isotope-labeled peroxynitrite (O¹⁵NOO⁻), and the resulting standard is mixed with representative samples in which nitrotyrosine formation is to be measured by mass spectrometry (MS). Nitropeptide MS/MS spectra are filtered using high mass accuracy Fourier transform MS (FTMS) detection of the nitrotyrosine immonium ion. Given that the nitropeptide pair is co-isolated for MS/MS fragmentation, the nitrotyrosine immonium ions (at m/z = 181 or 182) can be used for relative quantitation with negligible isotopic interference at a mass resolution of greater than 50,000 (FWHM, full width at half-maximum). Furthermore, the standard potentially allows for the increased signal of nitrotyrosine-containing peptides, thus facilitating selection for MS/MS in a data-dependent mode of acquisition. We have evaluated the methodology in terms of nitrotyrosine site identification and relative quantitation using nitrated peptide and protein standards.     

Compounds with Antiviral,Anti-Inflammatory and Anticancer Activity Identified in Wine from Hungary’s Tokaj Region via High Resolution Mass Spectrometry and Bioinformatics Analyses

(1) Background: Wine contains a variety of molecules with potential beneficial effects on human health. Our aim was to examine the wine components with high-resolution mass spectrometry including high-resolution tandem mass spectrometry in two wine types made from grapes with or without the fungus Botrytis cinerea, or “noble rot”. (2) For LC-MS/MS analysis, 12 wine samples (7 without and 5 with noble rotting) from 4 different wineries were used and wine components were identified and quantified. (3) Results: 288 molecules were identified in the wines and the amount of 169 molecules was statistically significantly different between the two wine types. A database search was carried out to find the molecules, which were examined in functional studies so far, with high emphasis on molecules with antiviral, anti-inflammatory and anticancer activities. (4) Conclusions: A comprehensive functional dataset related to identified wine components is also provided highlighting the importance of components with potential health benefits.     

Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

A novel liquid chromatography-mass spectrometry (LC-MS) approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI) coupled to hydrophilic interaction liquid chromatography (HILIC) was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID) fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL) prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.     

Direct Analysis in Real Time (DART) of an Organothiophosphate at Ultrahigh Resolution by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Tandem Mass Spectrometry

Direct analysis in real time (DART) is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae.     

Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry

The parallel reaction monitoring (PRM) assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach.     

毛细管电泳-质谱联用技术在环境分析中的应用

毛细管电泳-质谱(CE-MS)联用技术综合了CE的快速、高分离能力与MS强大的鉴定功能等特点,已经成为一种重要的分离分析手段。文章对CE-MS联用的发展、特点及在环境分析领域的应用进展予以综述。     

Direct Mass Spectrometry of Polymers

The analysis of polymers by direct mass spectrometry is reviewed, and the principles of the method and some experimental aspects are discussed. Both pyrolysis and desorption methods are described. The mass spectrometric method provides the characterisation of intractable materials and their detection at the submicrogram level; the simultaneous identification and detection of additives or oligomers contained in polymer samples; the identification of components of polymer mixtures, the sequential analysis of copolymers; the identification of the primary thermal fragmentation products of polymers. Direct mass spectrometry has been widely applied to the structural analysis of synthetic and natural polymers. Published work covers nearly all classes of polymers.     

高效液相色谱-串联三重四极杆质谱联用技术在烟草化学分析中的应用

文章就高效液相色谱-串联三重四极杆质谱联用技术(LC-MS/MS)在烟草化学分析研究中的应用进行了综述。对LC-MS/MS法在烟草化学分析中的农残分析、有机胺分析、代谢物分析、氢氰酸、醛酮类、酚类成分分析及生物碱、糖苷类等其它成分分析作了简要介绍,并展望了其在未来的应用前景。     

Biomolecular Profiling by MALDI-TOF Mass Spectrometry in Food and Beverage Analyses

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has frequently been applied to the analysis of biomolecules. Its strength resides not only in compound identification but particularly in acquiring molecular profiles providing a high discriminating power. The main advantages include its speed, simplicity, versatility, minimum sample preparation needs, and a relatively high tolerance to salts. Other benefits are represented by the possibility of automation, high throughput, sensitivity, accuracy, and good reproducibility, allowing quantitative studies. This review deals with the prominent use of MALDI-TOF MS profiling in food and beverage analysis ranging from the simple detection of sample constituents to quantifications of marker compounds, quality control, and assessment of product authenticity. This review summarizes relevant discoveries that have been obtained with milk and milk products, edible oils, wine, beer, flour, meat, honey, and other alimentary products. Marker molecules are specified: proteins and peptides for milk, cheeses, flour, meat, wine and beer; triacylglycerols and phospholipids for oils; and low-molecular-weight metabolites for wine, beer and chocolate. Special attention is paid to sample preparation techniques and the combination of spectral profiling and statistical evaluation methods, which is powerful for the differentiation of samples and the sensitive detection of frauds and adulterations.     

色谱-质谱联用技术在环境监测中的应用

色谱-质谱联用技术是现代分析测试技术的重要研究方向。经过几十年的发展,它已经在环境监测领域发挥了巨大的作用。文章介绍了该技术在水体监测、空气监测和土壤监测方面的应用。     

Mass Informatics: From Mass Spectrometry Peaks to Biological Pathways

In this review we will introduce the field of mass informatics, a branch of bioinformatics concerned with the analysis of data from mass spectrometry. As we shall demonstrate, this short definition hides a surprisingly diverse and challenging topic, driven by the remarkable versatility of the mass spectrometer. We first introduce the essential properties of the mass spectrum and highlight its key differences from the more common data types in high-throughput bioinformatics (sequence, microarray and image data). We then explore the breadth of biochemistry accessible through the associated algorithmic challenge of spectral identification. Finally, we demonstrate instances where data-mining techniques can be applied to large-scale spectral libraries, thereby extracting latent biological insight.     

基于高分辨质谱技术的植物源性药食同源特色农产品中10种农药残留的测定和快速筛查

建立了人参、五味子、刺五加、人参花、灵芝和灵芝孢子粉基质中10种农药残留的高分辨液相质谱检测及筛查方法,样品中残留的农药采用乙腈提取,经氯化钠及乙酸钠盐析分层,提取液经无水硫酸镁、N-丙基乙二胺(PSA)和石墨化炭黑(GCB)吸附剂分散固相萃取净化,用高效液相色谱-高分辨质谱定性.在上述检测方法条件下,所测的10种农药...     

Comparison of Liquid Chromatography with Fluorescence Detection and Gas Chromatography/Mass Spectrometry for the Determination of Polycyclic Aromatic Hydrocarbons in Environmental Samples

Liquid chromatography (LC) with fluorescence detection and gas chromatography/mass spectrometry (GC/MS) have been compared for the determination of polycyclic aromatic hydrocarbons (PAHs) in a variety of environmental samples. Three sets of data are presented in this paper in which LC/fluorescence and GC/MS were used for the analysis of the same samples. These three data sets include the comparison of results from: (1) certification measurements for three natural matrix Standard Reference Materials (SRM's), (2) an international round robin for the determination of PAHs in air and diesel particulate samples, and (3) the analysis of four marine sediment reference materials. The results from these studies indicate that the two techniques generally provide comparable results for the measurement of PAHs in environmental samples (in the range of 0.1 to 300 ng/g), with differences in the two techniques between 5–20%. However, at low levels, anthracene and perylene are best measured using LC/fluorescence because of their selective and sensitive fluorescence detection characteristics. In contrast, GC/MS provides more accurate results for the determination of benzo[ghi]perylene because of its low fluorescence sensitivity.     

高效液相色谱-串联质谱法测定化妆品中4种防晒剂

建立了化妆品中4种防晒剂的高效液相色谱-串联质谱测定方法。样品用四氢呋喃/甲醇/水体系提取,以水(含φ(氨水)=0.05%)-甲醇(含φ(氨水)=0.05%)为流动相梯度洗脱,经Phenomenex PFP色谱柱分离后,在多反应监测(MRM)模式下以保留时间和离子对(母离子和两个子离子)信息比较进行定性和定量分析。4种防晒剂在10~500μg·L-1范围内线性关系良好,定量限(LOQ)为10~30 mg·kg-1,方法回收率为85.8%~105.8%,相对标准偏差(n=6)为1.8%~5.5%。此方法可用于化妆品中4种防晒剂的确证与定量测定。     

热重-质谱联用技术应用进展

简要介绍了热重-质谱联用技术(TG-MS)在近几年的应用进展,内容主要包括TG-MS在燃料化学、材料、聚合物、含能材料、生物化学等领域取得的研究成果,建议国内烟草行业也应采用TG-MS联用技术。     

辉光放电质谱法测定高纯锡中的杂质元素

采用辉光放电质谱法对高纯锡中的Mg、Al、Ca、Fe等20个痕量杂质元素进行测定。对仪器的工作参数进行了优化,并对杂质浓度与预溅射时间的关系,测量的准确性和重现性进行了讨论。     

Mass Spectrometry Methodology in Lipid Analysis

Lipidomics is an emerging field, where the structures, functions and dynamic changes of lipids in cells, tissues or body fluids are investigated. Due to the vital roles of lipids in human physiological and pathological processes, lipidomics is attracting more and more attentions. However, because of the diversity and complexity of lipids, lipid analysis is still full of challenges. The recent development of methods for lipid extraction and analysis and the combination with bioinformatics technology greatly push forward the study of lipidomics. Among them, mass spectrometry (MS) is the most important technology for lipid analysis. In this review, the methodology based on MS for lipid analysis was introduced. It is believed that along with the rapid development of MS and its further applications to lipid analysis, more functional lipids will be identified as biomarkers and therapeutic targets and for the study of the mechanisms of disease.     

气相色谱/质谱法在环境水样分析中的应用

使用树脂吸附、溶剂洗脱、GC/MS联用技术对某地一化工厂向河流中直接排放的废水、河流的上河水和下河水及地下水进行了分析和检验,检测出样品中所含的数十种有机化合物。该方法快速、灵敏,且定性定量准确,为行政管理部门实施监督和管理,工厂对排放水进行控制和处理及工厂周围居民对所饮用水的水质了解,提供了有效的途径和依据。