信息型常见毒物质谱用户库的建立及其在毒物快速筛选上的应用研究

质谱定性是目前世界上最通用的定性分析方法之一,在法庭科学领域毒物分析实践中,质谱一直是对未知样品进行药毒物筛选检测的利器.     

恩诺沙星粉中未知添加物的确证

应用非靶向分析技术,筛查、分析和确证恩诺沙星粉(水产用)中的非法添加物。分别制备甲酸酸化、碳酸钠碱化的恩诺沙星粉供试品溶液,经超高效液相色谱-二极管阵列检测器(UPLC-PDA)检测初筛,获取未知物色谱图。应用超高效液相色谱-飞行时间高分辨质谱(UPLC-TOF-HRMS),在正、负离子模式下对酸化、碱化样液进一步检测,获得未知物母离子和二级特征碎片的精确质荷比、同位素信息,并应用SCIEX OS软件进行分析推导。最后取疑似化合物对照品进行确证研究。UPLC-PDA初筛结果显示:酸化样液在1.870 min、5.122 min,碱化样液在5.122 min,均发现高响应未知色谱峰。对吸收波长和峰面积进行分析,推测含2个未知物,且未知物1(1.870 min)与未知物2(5.122 min)在酸性/碱性条件下可能发生转换。SCIEX OS软件分析推导结果显示:未知物2,母离子分子式拟合为C₁₁H₈O₂,二级碎片结构解析含1个苯环、2个羰基和1个通过成环连接的丙烯结构,推测为甲萘醌;未知物1的分子离子峰为C₁₁H₉O₅S^-,二级碎片仅采集到HSO₃^-,丢失部分与未知物2一致,结合甲萘醌常见衍生物类型,推测为亚硫酸氢钠甲萘醌。取甲萘醌、亚硫酸氢钠甲萘醌对照品进行对比研究,UPLC-PDA检测结果显示:未知物1与亚硫酸氢钠甲萘醌、未知物2与甲萘醌,保留时间和紫外光谱一致;向供试溶液中添加对照品溶液后检测,未知物为单一峰。UPLC-TOF-HRMS检测发现:未知物1与亚硫酸氢钠甲萘醌保留时间一致,一级质谱质量偏差为1.0×10^-6,二级谱库匹配度为100%;未知物2与甲萘醌保留时间一致,一级质谱质量偏差为0.6×10^-6,二级谱库匹配度为99.7%。未知物1和2的结构得以确证。亚硫酸氢钠甲萘醌可止血,与恩诺沙星治疗败血症的适应证相应,佐证试验结果。随着对兽药非法添加行为的严格监管和严厉打击,非法添加物和添加手段愈发隐蔽,常规靶向分析难以满足监控需求。该文详述的使用UPLC-PDA结合UPLC-TOF-HRMS对未知物进行非靶向分析的技术,可为药品、食品、保健品、化妆品及农药等产品中非法添加物的筛查和确证提供思路和技术参考。     

高通量药物筛选现代检测技术研究进展

高通量药物筛选是发现创新药物的重要技术途径.高通量筛选结果必须通过适当的检测方法才能反映出来,检测技术是实现高通量药物筛选的基础.本文综述了近年来有关光学分析、色谱分析、热分析、电化学分析、质谱、核磁共振等现代检测技术在高通量药物筛选研究中的进展.     

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。     

基于微流控芯片-质谱联用的细胞分析研究进展

微流控芯片与质谱联用为细胞研究提供了一个很好的研究平台.质谱的高灵敏度和对化合物独特的鉴别能力可以从复杂的化学信息背景中筛选识别出微量目标物,是细胞分析理想的检测手段.本文重点综述了近年来基于微流控芯片-质谱联用技术的细胞研究进展,从芯片-电喷雾质谱(ESI-MS)接口技术、集成化的样品前处理技术、细胞的药物代谢和细胞相互作用研究及基质辅助激光解吸电离质谱(MALDI-MS)的细胞分析应用等方面总结了最新的方法和技术发展.并展望了芯片-质谱联用新技术应用于细胞分析的可能性.     

敞开式电离质谱技术在法医毒物分析中的应用

敞开式电离质谱(Ambient ionization mass spectrometry,AIMS)是指在大气压环境下,无需或只需简单的样品前处理即可对样品中目标物进行分析的质谱技术。AIMS具有简单、快速、无损和适用范围广等优势,被广泛应用于法医毒物分析领域。该文对敞开式电离(Ambient ionization,AI)技术进行了简单概述,将检材分为体内检材和体外检材两大类,综述了AIMS技术在不同类型检材毒物分析中的应用,并对其在法医毒物分析中的发展前景进行了展望。     

原位衍生化技术在液相色谱和液相色谱-质谱联用分析中的应用

衍生化是将待分析物转化为更适合的物质形式以便于分析的有效手段。原位衍生化技术作为一种常用的柱前衍生化方法,可以在样品基质中同时完成分析物的萃取和衍生化,具有高效、灵敏和选择性好的优点。原位衍生化结合其他前处理技术广泛用于胺类、醛酮类、醇类、酚类、羧酸和巯基化合物的分析中,在生物、药物、食品、环境、化妆品分析等领域有广泛的应用。该文概述了原位衍生化的反应类型和代表性衍生试剂,综述了原位衍生化技术在液相色谱和液相色谱-质谱联用分析中的应用,并展望其发展趋势。     

利用亲和选择筛选法从组合化学库中筛选新药

组合化学方法可以产生大量的新化合物供新药筛选，但传统的逐一筛选法不能满足如此数量庞大的化合物，因此，针对混合物进行筛选显得非常重要，亲和选择筛选法利用药物作用的靶蛋白与潜在药物之间的亲和活性，使目标化合物与大量无亲和活性的化合物分离，然后只对有亲和活性的化合物进行结构鉴定，从而快速地从大量混合物中找到目标化合物，本文着重讨论了亲和选择筛选的的几种形，相应技术和在组合化学库筛选中的应用，亲和选择筛选大体分为两种方式：一种是将靶蛋白固定在支持物上，有亲和活力的化合物被保留，大量非亲和化合物被洗掉，另一种是在溶液中靶蛋白与混合物库孵育，然后利用受体配基复合物与不结合的游离化合性质的判别进行区分，亲和选择筛选法也适合于化合物的种类和含量都未知的天然提取物的筛选。     

未知酒用香精组分的分离与鉴定

普通蒸馏、分馏及红外光谱测定等是有机化学实验的基础技术;而未知物结构推断是一个综合利用其理化性质进行逻辑推理的过程。以现实生活中酒用香精组分的分离与鉴定实验为例,介绍如何通过不同实验技术的合理组合,以达到培养学生综合运用实验技术、科学分析实验结果、合理推断未知物结构能力的教学目的。     

表面增强拉曼散射方法检测公共安全类毒物的研究进展

公共安全类毒物直接威胁人们的生命健康安全。表面增强拉曼散射(SERS)技术的超灵敏特点为复杂基质中痕量毒物的快速检测提供了分析策略,极大地拓展了其应用范围,有着广阔的应用前景。该文综述了SERS技术在公共安全类物质检测方面的研究进展,包括对节球藻毒素、芥子气、琥珀胆碱、甲基对硫磷、氰化物、汞离子、亚硝酸盐等毒物的检测。从基底种类的选择和评估、检测限、重复性和实际应用的角度介绍了检测体系的建立过程。分析了这些方法及其在应用中面临的技术挑战与机遇,展望了SERS技术解决现场实际检测难题的发展方向。     

邻苯二胺产品中针状未知化合物的结构鉴定

从邻苯二胺产品中分离出一种白色针状未知化合物,用液相色谱（ＨＰＬＣ）和气相色谱（ＧＣ）鉴定其纯度后,同时进行元素、红外光谱（ＩＲ）、紫外光谱（ＵＶ）、质谱（ＭＳ）、核磁共振（ＮＭＲ）氢谱及碳谱分析。根据分析的结果进行解析,最后确定未知针状不纯物中其主成分为２,１,３－苯并硫咪唑或２,１,３－硫二氮杂茚（Ｃ６Ｈ４Ｎ２Ｓ）（２,１,３－ｂｅｎｚｏｔｈ－ｉａｄｉａｚｏｌｅ）。     

Screening DNA Adducts by LC–ESI–MS–MS: Application to Screening New Adducts Formed from Acrylamide

A method for screening DNA adducts with unknown chemical structures was developed; it involves the use of liquid chromatography–electrospray ionization-tandem mass spectrometry (LC–ESI–MS–MS). In electrospray ionization (ESI) product ion mass spectra of guanine adducts, fragment ions were observed at m/z 152 and 135. Precursor ion scan analysis of these fragment ions indicated that the screening of DNA adducts would be possible. The developed method was used for the analysis of DNA adducts derived from acrylamide, which is not only a constituent of many commonly consumed foods but also a carcinogenic compound. We successfully discovered new guanine adducts. The results of this study indicate that the developed method is useful for screening new DNA adducts.     

减肥产品中非法添加西布曲明类似物的ESI-MS/MS检测与确证

通过分析西布曲明和减肥类健康产品中未知化合物质谱图的质谱信息,由高分辨串联质谱获得裂解碎片离子的精密质量数,质谱软件给出碎片的可能组成,推测了西布曲明和未知化合物的质谱裂解途径,进而推测出该化合物的结构。并通过合成该结构的化合物,采用液相色谱-串联质谱法对样品作确证检验,证实样品中添加了新的西布曲明类似物。该实验提供了一种可用于检测和确证健康产品中非法添加合成药物未知类似物的方法。     

Liquid Chromatography Tandem Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy of Magnesium (II) Gluconate Solution

Magnesium gluconate is a classical pharmaceutical compound used as a source of magnesium for the prevention and treatment of hypomagnesemia. To the best of our knowledge, a robust and reliable liquid chromatography tandem mass spectrometry technique has not yet been reported for the qualitative and quantitative analysis of magnesium gluconate. This study describes the method development for the LC–ESI–MS/MS analysis of magnesium gluconate using three different reversed-phase HPLC conditions (Method I–III) with comprehensive fragmentation pattern and the structural characterization by NMR spectroscopy. The LC–MS and NMR data were found in accordance with the structure of magnesium gluconate. When magnesium gluconate was dissolved in the acetonitrile and water–methanol solutions, it exists in situ in three different forms: magnesium gluconate itself, gluconic acid, and magnesium gluconate chelate with gluconic acid by a coordinate covalent bond. Method I exhibited pseudo-molecular ion peaks with more magnesium gluconate chelates with gluconic acid, while method II showed an adduct of magnesium gluconate with the solvent along with the molecular ion peak. There was no pseudo-molecular ion peaks found in method III. Thus, method III was found to be the more accurate, robust and reliable LC–MS method for the qualitative and quantitative analysis, structural characterization, and could also be suitable for the pharmacokinetic study of magnesium gluconate. The detailed fragmentation analysis might be useful for the structural characterization of unknown divalent organometallics.     

Pyrolysis GC/MS analysis of a bacterial population in a saline activated sludge system—Identification of the origin of the pyrolysis product 2-methylpyrimidine

During the investigation of problems with the physical handling of sludge from a saline activated sludge wastewater system, pyrolysis/GC/MS was used in an attempt to determine whether changes in the bacterial population in the sludge were occurring. The pyrolysis GC/MS analysis revealed an unknown peak among other typical bacterial pyrolysis products. This unknown was identified as 2-methylpyrimidine. This pyrolysis product was only found in appreciable amounts in samples from other saline systems but not in freshwater systems analyzed as points of comparison for the system of concern. Further investigation confirmed the source of 2-methylpyrimidine to be ectoine, a compound produced by halophilic bacteria as a compatible solute for osmoadaptation. Pyrolysis GC/MS was shown to be a useful tool to indicate the presence of ectoine in halophilic bacteria.     

Role of hypaphorine in the toxicity of Astragalus lusitanicus

Hypaphorine, an alpha-N,N,N-trimethyltryptophan betaine, was isolated, for the first time, from Astragalus lusitanicus Lam. (Fabaceae), a plant highly toxic for lambs and goats. This alkaloid was characterized by NMR and MS analysis. Hypaphorine was previously reported to be a convulsive poison. To confirm the toxicity, it was synthesized and tested in goats. Hypaphorine was shown to be non-toxic for goats even at a high dose of 2 g kg(-1) by oral administration.     

Exact mass measurement of product ions for the structural confirmation and identification of unknown compounds using a quadrupole time-of-flight spectrometer: a simplified approach using combined tandem mass spectrometric functions

This article describes a simple method to perform lock mass corrected accurate mass measurements in tandem mass spectrometry (MS/MS) with a quadrupole time-of-flight (Q-TOF) mass spectrometer. The experimental approach consists of using the protonated molecule of a known compound, which is measured in a MS/MS function using low collision energy (no fragmentation), as mass calibrator. The unknown compound is acquired in MS/MS mode albeit using high collision energy. After the acquisition, the two MS/MS spectra of unknown and mass calibrator are combined, and the fragments of the unknown are lock mass corrected by using the protonated molecule of the mass calibrator. To prove this concept, 10 compounds were analyzed using this approach, the fragments interpreted and, where possible, related to structural data available in the literature. All the unequivocally assigned fragments were accurately mass measured with mass errors within appropriate limits, i.e. for m/z values <200 with a mass tolerance of 3 mDa while for m/z > 200 the mass tolerance is expressed as 10 ppm.     

LC-MS/MS in the elucidation of an isomer of the recreational drug methylenedioxy ethylamphetamine: methylenedioxy dimethylamphetamine

This paper describes the surplus value of a quadrupole-orthogonal acceleration TOF mass spectrometer, coupled to a liquid chromatographic separation system, for the unequivocal identification and structural elucidation of an unknown compound in the field of designer drugs. In a patient sample set (blood, tissues, vitreous humor, etc.), analyzed with a dedicated liquid chromatographic-fluorescence detection method for the determination of methylenedioxy amphetamine, methylenedioxy methamphetamine, and methylenedioxy ethylamphetamine (MDEA), a "strange" inexplicable peak appeared at a retention time not corresponding to any of our reference materials. Based on the identical excitation and emission wavelengths in detection, and a retention behavior comparable to MDEA, it was assumed that this unknown compound was an isomer of the recreational drug MDEA. With a simple and straightforward methodological crossover between LC fluorescence detection and LC-MS/MS, additional information for structural elucidation was easily obtained. Chromatographic separation was achieved on a Hypersil BDS C18 column (fluorescence detection part) and on a Hypersil BDS phenyl column (mass spectrometric detection part). MS showed that the unknown compound's molecular mass was identical to that of MDEA, and, in addition, its fragmentation pattern too proved quite similar to that of MDEA. A thorough literature overview and study of the fragmentation pattern by means of the MS/MS spectrum led to an evidence-based hypothesis of 3,4-methylenedioxy N,N-dimethylamphetamine (MDDM) being the unknown compound. To confirm this hypothesis, MDDM was synthesized and its presence in our biological sample was finally demonstrated by co-injection with alternatively synthesized MDDM and MDEA. This application shows the synergism between LC and MS in the elucidation of unknown compounds, nevertheless emphasizing the essence of chromatographic separation when dealing with isomers.     

Ultra‐performance liquid chromatography tandem mass spectrometry for the rapid,simultaneous analysis of ziprasidone and its impurities

The separation and characterization of the unknown degradation product of second‐generation antipsychotic drug ziprasidone are essential for defining the genotoxic potential of the compound. The aim of this study was to develop a simple UHPLC method coupled with tandem mass spectrometry (MS/MS) for chemical characterization of an unknown degradant, and the separation and quantification of ziprasidone and its five main impurities (I–V) in the raw material and pharmaceuticals. Chromatographic conditions were optimized by experimental design. The MS/MS fragmentation conditions were optimized individually for each compound in order to obtain both specific fragments and high signal intensity. A rapid and sensitive UHPLC–MS/MS method was developed. All seven analytes were eluted within the 7 min run time. The best separation was obtained on the Acquity UPLC BEH C₁₈ (50 × 2.1 mm × 1.7 μm) column in gradient mode with ammonium‐formate buffer (10 mm ; pH 4.7) and acetonitrile as mobile phase, with the flow rate of 0.3 mL min^?1 and at the column temperature of 30°C. The new UHPLC–MS/MS method was fully validated and all validation parameters were confirmed. The fragmentation pathways and chemical characterization of an unknown degradant were proposed and it was confirmed that there are no structural alerts concerning genotoxicity.