质谱直接定量分析技术的应用进展

质谱直接定量分析指待测样品在引入质谱离子源之前,不经色谱分离,直接利用质谱信号对分析物进行含量测定的分析技术。该技术在很大程度上缩短了样品的检测周期,能够满足快速在线、原位分析的需求,目前已在质谱成像、单细胞分析以及在线反应监测等领域展现出广阔的应用前景。本工作综述了与质谱直接定量分析有关的质谱技术、样品处理方法以及相关应用,并展望质谱定量分析的发展趋势。     

Current mass spectrometry strategies for the analysis of pesticides and their metabolites in food and water matrices

Analysis of pesticides and their metabolites in food and water matrices continues to be an active research area closely related to food safety and environmental issues. This review discusses the most widely applied mass spectrometric (MS) approaches to pesticide residues analysis over the last few years. The main techniques for sample preparation remain solvent extraction and solid‐phase extraction. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) approach is being increasingly used for the development of multi‐class pesticide residues methods in various sample matrices. MS detectors—triple quadrupole (QqQ), ion‐trap (IT), quadrupole linear ion trap (QqLIT), time‐of‐flight (TOF), and quadrupole time‐of‐flight (QqTOF)—have been established as powerful analytical tools sharing a primary role in the detection/quantification and/or identification/confirmation of pesticides and their metabolites. Recent developments in analytical instrumentation have enabled coupling of ultra‐performance liquid chromatography (UPLC) and fast gas chromatography (GC) with MS detectors, and faster analysis for a greater number of pesticides. The newly developed “ambient‐ionization” MS techniques (e.g., desorption electrospray ionization, DESI, and direct analysis in real time, DART) hyphenated with high‐resolution MS platforms without liquid chromatography separation, and sometimes with minimum pre‐treatment, have shown potential for pesticide residue screening. The recently introduced Orbitrap mass spectrometers can provide high resolving power and mass accuracy, to tackle complex analytical problems involved in pesticide residue analysis. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:907–939, 2011     

Review on microbial metabolomics of probiotics and pathogens: Methodologies and applications

In recent years, microbial metabolomics, a new field that has attracted wide attention, provides a map of metabolic pathways and clarifies the interaction mechanism between microorganisms and hosts. Many microorganisms are found in the human intestine, oral cavity, vagina, etc. Probiotics could maintain the good health of the host, while pathogens and an imbalance of bacterial flora lead to a series of diseases of the body and mind. Metabolomics is a science for qualitative and quantitative analysis of all metabolites in an organism or biological system, which could provide key information to understand the related metabolic pathways and associated changes. This approach analyzes the final products of cellular regulatory processes, the level of which can be regarded as the ultimate response of the biological system to genetic or environmental changes. Microbial metabolomics has been widely used in different research fields, such as microbial phenotypic classification, mutant screening, metabolic pathways, microbial metabolic engineering, fermentation engineering monitoring and optimization, microbial environmental pollution, and so on. However, there are only a few reviews on microbial metabolomics of probiotics and pathogens. This review summarizes the main methodologies, including sample preparation, identification of metabolites, data processing, and analysis. Recent applications in microbial metabolomics of probiotics and pathogens are also described. This paper first summarized the research progress and application of microbial metabolomics from two aspects: probiotics and pathogenic bacteria. Probiotics and pathogenic bacteria do not exist independently most of the time; hence, these were reviewed in the research field of coexistence of probiotics and pathogenic bacteria, which was subdivided into important microbial research fields closely related to human health, including the human gut, oral cavity, food, and nutrition-related microorganisms. Then, the main problems and trends associated with microbial metabolomics are discussed.     

Development of LC/MS Techniques for Comprehensive Metabolome Analysis

Metabolomics is a rapidly evolving field for studying biological systems and discovering potential disease biomarkers. For any metabolomics application, metabolome analysis with adequate sensitivity and specificity is essential in defining the metabolome. Ideally, all metabolites present in a biological system are qualitatively and quantitatively profiled. Unfortunately, due to technical limitations, only a fraction of metabolites are currently analyzed by using techniques such as NMR and mass spectrometry (MS). Due to limited metabolome coverage, many important metabolome networks and some subdue changes in the metabolome may not be revealed with current techniques. In this presentation, several technical issues related to the development of LC/MS for enabling metabolome analysis will be discussed. Because of great diversity of chemical and physical properties of metabolites, we have been developing an isotope labeling LC/MS workflow with a goal of improving the metabolome coverage in analyzing biological samples such as human biofluids and tissue samples. Several labeling chemistries will be described to provide isotope tags to the metabolites for sensitive detection and accurate quantification. LC methods including multi-dimensional separation to separate the labeled metabolites with high efficiency will be discussed. New protocols for MS analysis, metabolite identification and quantitative data processing will be presented.     

Analytical strategies for identifying drug metabolites

With the dramatic increase in the number of new chemical entities (NCEs) arising from combinatorial chemistry and modern high-throughput bioassays, novel bioanalytical techniques are required for the rapid determination of the metabolic stability and metabolites of these NCEs. Knowledge of the metabolic site(s) of the NCEs in early drug discovery is essential for selecting compounds with favorable pharmacokinetic credentials and aiding medicinal chemists in modifying metabolic "soft spots". In development, elucidation of biotransformation pathways of a drug candidate by identifying its circulatory and excretory metabolites is vitally important to understand its physiological effects. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have played an invaluable role in the structural characterization and quantification of drug metabolites. Indeed, liquid chromatography (LC) coupled with atmospheric pressure ionization (API) MS has now become the most powerful tool for the rapid detection, structure elucidation, and quantification of drug-derived material within various biological fluids. Often, however, MS alone is insufficient to identify the exact position of oxidation, to differentiate isomers, or to provide the precise structure of unusual and/or unstable metabolites. In addition, an excess of endogenous material in biological samples often suppress the ionization of drug-related material complicating metabolite identification by MS. In these cases, multiple analytical and wet chemistry techniques, such as LC-NMR, enzymatic hydrolysis, chemical derivatization, and hydrogen/deuterium-exchange (H/D-exchange) combined with MS are used to characterize the novel and isomeric metabolites of drug candidates. This review describes sample preparation and introduction strategies to minimize ion suppression by biological matrices for metabolite identification studies, the application of various LC-tandem MS (LC-MS/MS) techniques for the rapid quantification and identification of drug metabolites, and future trends in this field.     

液相色谱-质谱用于代谢标志物的发现和鉴定

代谢组学是测量相对分子质量1 000以下的内源性代谢物的科学,目前已在疾病研究、药物研发及植物和微生物等领域均得到重视,是研究小分子的一个十分有用的工具。它以组织、体液或细胞为研究对象,最常用的技术是质谱和NMR。一般来说,代谢组学的研究包括样品采集、预处理、代谢组数据采集、多变量数据分析、标志物发现和识别及最终的生物解释。由于缺乏数据库及标样,代谢标志物的识别是研究的一个瓶颈。 在这里,我们将报告一个基于色谱-质谱联用技术的集成识别策略,包括多变量数据分析、精确分子量测定、质谱碎片裂解规律、色谱保留规律、馏分微制备、亲和色谱、酶解等。 药物作用机理和疾病标志物的代谢组学研究将作为例子阐明我们的策略。     

基于液相色谱-质谱联用技术的蛋白质类肿瘤标志物定量方法研究进展

液相色谱-质谱（LC-MS）联用技术因具有高通量、高灵敏度等优点而成为发现、验证生物标志物及对生物标志物进行定量分析的有力工具。近年来,LC-MS在临床应用中,特别是在定量肿瘤生物标志物方面做出了重要贡献。研究人员通过不同的设计原理开发出多种定量方法,逐步实现了对高度复杂样品中蛋白质类肿瘤标志物的准确定量。本文从用于定量蛋白质类肿瘤标志物的样品前处理方法及LC-MS分析中的质谱扫描策略两个方面,对近年来的主要定量方法进行总结。     

MALDI-TOF MS与16SrDNA方法对肠杆菌科微生物鉴定比较分析

为了研究基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)法鉴定肠杆菌科微生物及其对微生物系统分类学相关分析的准确性,采用MALDI-TOF MS对金桔表面分离的10种肠杆菌科微生物进行蛋白质图谱收集,通过比对图谱特征峰实现微生物的鉴定与系统进化学分析;同时对10种微生物进行16SrDNA提取与测序,得到分子生物化学水平鉴定,并采用邻近连接法对16SrDNA序列做系统进化树分析。结果表明:MALDI-TOF MS与16SrDNA测序对10种肠杆菌科微生物鉴定结果中,克雷伯菌属2株菌鉴定种级有偏差,其他8种一致;MALDI-TOF MS与16SrDNA测得的数据都可计算微生物相关性,从而得到微生物系统发育树,两株系统发育树中同属级微生物归类的亲缘位置与方向一致,但不同属肠杆菌科微生物的亲缘距离与位置差异较大。MALDI-TOF MS法鉴定农产品表面微生物具有快速、准确的特点,但准确建立系统发育相关性还需要扩大数据库和优化算法。     

Urinary nucleosides

The methods of analysis, origins, and clinical significance of urinary nucleosides are reviewed through 1997. Structures, chromatographic and mass spectral data and references to the clinical literature are presented for each of the 57 nucleosides currently identified in normal and pathogenic human urine samples. Data from the HPLC separation and GC/MS analysis of 37 individual HPLC fractions are presented and discussed. Methods, including sample preparation techniques, used for the analysis of urinary nucleosides including GC, HPLC, GC/MS, HPLC/MS and immunoassays are compared and the advantages and limitations of each method described. The conclusion is drawn that the urinary nucleosides do serve as biomarkers of cancer and other diseases, but analytical methods need further improvement if clinical decisions are to be made based on the levels of nucleosides in human urine.     

The application of mass spectrometry in molecular dosimetry: Ethylene oxide as an example

Mass spectrometry plays an increasingly important role in the search for and quantification of novel chemically specific biomarkers. The revolutionary advances in mass spectrometry instrumentation and technology empower scientists to specifically analyze DNA and protein adducts, considered as molecular dosimeters, derived from reactions of a carcinogen or its active metabolites with DNA or protein. Analysis of the adducted DNA bases and proteins can elucidate the chemically reactive species of carcinogens in humans and can serve as risk‐associated biomarkers for early prediction of cancer risk. In this article, we review and compare the specificity, sensitivity, resolution, and ease‐of‐use of mass spectrometry methods developed to analyze ethylene oxide (EO)‐induced DNA and protein adducts, particularly N7‐(2‐hydroxyethyl)guanine (N7‐HEG) and N‐(2‐hydroxyethyl)valine (HEV), in human samples and in animal tissues. GC/ECNCI‐MS analysis after HPLC cleanup is the most sensitive method for quantification of N7‐HEG, but limited by the tedious sample preparation procedures. Excellent sensitivity and specificity in analysis of N7‐HEG can be achieved by LC/MS/MS analysis if the mobile phase, the inlet (split or splitless), and the collision energy are properly optimized. GC/ECNCI‐HRMS and GC/ECNCI‐MS/MS analysis of HEV achieves the best performance as compared with GC/ECNCI‐MS and GC/EI‐MS. In conclusion, future improvements in high‐throughput capabilities, detection sensitivity, and resolution of mass spectrometry will attract more scientists to identify and/or quantify novel molecular dosimeters or profiles of these biomarkers in toxicological and/or epidemiological studies. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:733–756, 2011     

Mass spectrometry for small molecule pharmaceutical product development: a review

Developing a pharmaceutical product has become increasingly difficult and expensive. With an emphasis on developing project knowledge at an earlier stage in development, the use of information-rich technologies (particularly MS) has continued to expand throughout product development. Continued improvements in LC/MS technology have widened the scope of utilizing MS methods for performing both qualitative and quantitative applications within product development. This review describes a multi-tiered MS strategy designed to enhance and accelerate the identification and profiling of both process- and degradation-related impurities in either the active pharmaceutical ingredient (API) or formulated product. Such impurities can be formed either during chemical synthesis, formulation, or during storage. This review provides an overview of a variety of orthogonal-mass spectrometric methodologies, namely GC/MS, LC/MS, and ICP-MS, in support of product development. This review is not meant to be all inclusive; however, it has been written to highlight the increasing use of hyphenated MS techniques within the pharmaceutical development area.     

Mass spectrometric based approaches in urine metabolomics and biomarker discovery

Urine metabolomics has recently emerged as a prominent field for the discovery of non‐invasive biomarkers that can detect subtle metabolic discrepancies in response to a specific disease or therapeutic intervention. Urine, compared to other biofluids, is characterized by its ease of collection, richness in metabolites and its ability to reflect imbalances of all biochemical pathways within the body. Following urine collection for metabolomic analysis, samples must be immediately frozen to quench any biogenic and/or non‐biogenic chemical reactions. According to the aim of the experiment; sample preparation can vary from simple procedures such as filtration to more specific extraction protocols such as liquid‐liquid extraction. Due to the lack of comprehensive studies on urine metabolome stability, higher storage temperatures (i.e. 4°C) and repetitive freeze‐thaw cycles should be avoided. To date, among all analytical techniques, mass spectrometry (MS) provides the best sensitivity, selectivity and identification capabilities to analyze the majority of the metabolite composition in the urine. Combined with the qualitative and quantitative capabilities of MS, and due to the continuous improvements in its related technologies (i.e. ultra high‐performance liquid chromatography [UPLC] and hydrophilic interaction liquid chromatography [HILIC]), liquid chromatography (LC)‐MS is unequivocally the most utilized and the most informative analytical tool employed in urine metabolomics. Furthermore, differential isotope tagging techniques has provided a solution to ion suppression from urine matrix thus allowing for quantitative analysis. In addition to LC‐MS, other MS‐based technologies have been utilized in urine metabolomics. These include direct injection (infusion)‐MS, capillary electrophoresis‐MS and gas chromatography‐MS. In this article, the current progresses of different MS‐based techniques in exploring the urine metabolome as well as the recent findings in providing potentially diagnostic urinary biomarkers are discussed. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:115–134, 2017.     

质谱技术在农药残留分析中的研究进展

现代农用化学品与农产品的数量和质量安全密切相关,农药残留问题一直是大众关注的焦点.采用灵敏、准确、可靠的质谱技术能够准确地对残留农药进行定性和定量分析,从而为农药登记、农药残留摄入风险评估、环境有益生物安全、食品及其加工品中农药残留监测与监管等方面提供有力的技术支撑,保障环境安全和人类健康.本文综述了各种质谱及其联用技...     

结构特异N-糖蛋白质组学研究进展

N-连接糖基化修饰是蛋白质上常见的翻译后修饰,发生在特征氨基酸序列N-X-T/S/C(X≠P)中的天冬酰胺上.N-连接糖具有五糖核心结构,包括高甘露糖型、杂合型和复杂型等3种主要类型.N-糖基化在修饰位点上具有微观和宏观不均一性,其功能与修饰位点和N-连接糖结构对应.对蛋白质N-糖基化位点和结构特异性的精准鉴定和定量,...     

Mass spectrometry‐based holistic analytical approaches for metabolite profiling in systems biology studies

Metabonomics and metabolomics represent one of the three major platforms in systems biology. To perform metabolomics it is necessary to generate comprehensive “global” metabolite profiles from complex samples, for example, biological fluids or tissue extracts. Analytical technologies based on mass spectrometry (MS), and in particular on liquid chromatography–MS (LC–MS), have become a major tool providing a significant source of global metabolite profiling data. In the present review we describe and compare the utility of the different analytical strategies and technologies used for MS‐based metabolomics with a particular focus on LC–MS. Both the advantages offered by the technology and also the challenges and limitations that need to be addressed for the successful application of LC–MS in metabolite analysis are described. Data treatment and approaches resulting in the detection and identification of biomarkers are considered. Special emphasis is given to validation issues, instrument stability, and QA/quality control (QC) procedures. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:884–906, 2011     

Ion spectrometric detection technologies for ultra‐traces of explosives: A review

In recent years, explosive materials have been widely employed for various military applications and civilian conflicts; their use for hostile purposes has increased considerably. The detection of different kind of explosive agents has become crucially important for protection of human lives, infrastructures, and properties. Moreover, both the environmental aspects such as the risk of soil and water contamination and health risks related to the release of explosive particles need to be taken into account. For these reasons, there is a growing need to develop analyzing methods which are faster and more sensitive for detecting explosives. The detection techniques of the explosive materials should ideally serve fast real‐time analysis in high accuracy and resolution from a minimal quantity of explosive without involving complicated sample preparation. The performance of the in‐field analysis of extremely hazardous material has to be user‐friendly and safe for operators. The two closely related ion spectrometric methods used in explosive analyses include mass spectrometry (MS) and ion mobility spectrometry (IMS). The four requirements—speed, selectivity, sensitivity, and sampling—are fulfilled with both of these methods. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:940–973, 2011     

Ion mobility spectrometry‐mass spectrometry (IMS‐MS) of small molecules: Separating and assigning structures to ions

The phenomenon of ion mobility (IM), the movement/transport of charged particles under the influence of an electric field, was first observed in the early 20th Century and harnessed later in ion mobility spectrometry (IMS). There have been rapid advances in instrumental design, experimental methods, and theory together with contributions from computational chemistry and gas‐phase ion chemistry, which have diversified the range of potential applications of contemporary IMS techniques. Whilst IMS‐mass spectrometry (IMS‐MS) has recently been recognized for having significant research/applied industrial potential and encompasses multi‐/cross‐disciplinary areas of science, the applications and impact from decades of research are only now beginning to be utilized for “small molecule” species. This review focuses on the application of IMS‐MS to “small molecule” species typically used in drug discovery (100–500 Da) including an assessment of the limitations and possibilities of the technique. Potential future developments in instrumental design, experimental methods, and applications are addressed. The typical application of IMS‐MS in relation to small molecules has been to separate species in fairly uniform molecular classes such as mixture analysis, including metabolites. Separation of similar species has historically been challenging using IMS as the resolving power, R, has been low (3–100) and the differences in collision cross‐sections that could be measured have been relatively small, so instrument and method development has often focused on increasing resolving power. However, IMS‐MS has a range of other potential applications that are examined in this review where it displays unique advantages, including: determination of small molecule structure from drift time, “small molecule” separation in achiral and chiral mixtures, improvement in selectivity, identification of carbohydrate isomers, metabonomics, and for understanding the size and shape of small molecules. This review provides a broad but selective overview of current literature, concentrating on IMS‐MS, not solely IMS, and small molecule applications. © 2012 Wiley Periodicals, Inc., Mass Spec Rev 32:43–71, 2013     

质谱法在药物立体异构体区分中的应用及发展

质谱法广泛应用于化学、生命科学、药学等领域,能够提供分子质量信息,有助于未知物结构的解析,具有分辨率高、信息量大、样品用量少、灵敏快速等优点,在测定有机化合物精确分子质量、结构解析、反应机理等方面发挥着重要的作用。手性药物是药学领域的一个研究热点,近年来质谱法逐渐被用于药物手性杂质区分中,而且随着质谱技术的不断发展和改进,其在手性区分和分析中越来越受关注。本工作主要介绍了质谱法在手性药物立体异构体杂质分析中的应用及发展历程,阐述了各类质谱技术用于手性异构体分析的原理和特点,其中详细举例介绍了质谱动力学方法和离子淌度质谱方法在手性杂质分析中的应用。通过对比分析目前已有的各类手性分析方法的优缺点,说明利用质谱法实现手性异构体的区分和定量测定具有明显的优势。质谱法用于药物手性异构体的分离具有快速、不需要复杂的样品前处理和昂贵的手性柱等特点,极大地提高了手性药物分析的效率和准确度。随着质谱分析技术的迅速发展,质谱法将在多手性中心药物的手性杂质分离和生物大分子分析（如多糖、多肽）等领域发挥巨大潜能。