固相微萃取-气相色谱-质谱法分析烟用浸膏挥发性成分

采用固相微萃取 -气相色谱 -质谱 ( SPME-GC/MS)法定性分析了烟用浸膏 -茉莉花浸膏的挥发性和半挥发性成分。探讨了不同萃取头、不同温度平衡样品及采样时间对分析检测结果的影响。结果表明 :5 0 /3 0μm DVB/Carboxen/PDMS纤维头于 65℃温度下采样 1 .0 h,可获得较满意的结果 ;共鉴定出 61种成分 ,占挥发和半挥发性成分总量的 89.79%。其中酯类化合物 ( 2 2种 )为主要成分 ,是香料的原料来源 ,占总的相对含量的 48.0 8% ;烯类 ( 1 9种 )为 1 7.95 % ;醇类 ( 1 3种 )为 2 3 .0 9%。乙酸苯甲酯 ( 1 4.5 2 % )、顺 -苯甲酸 -3 -己烯-1 -酯 ( 1 4.1 1 % )、芳樟醇 ( 1 3 .1 6% )和α-金合欢烯 ( 1 2 .66% )是相对含量最多的成分。此方法适用于对样品简便、快速地定性分析     

超高效液相色谱/四极杆-飞行时间质谱法检测22种禁用和限用合成色素

建立有色饮料中22种禁用和限用合成色素的固相萃取超高效液相色谱/四极杆-飞行时间质谱快速检测方法。样品经固相萃取柱萃取,氨水-甲醇解吸,按GB/T5009-2003进行后处理,经超高效液相色谱/四极杆-飞行时间质谱检测,通过Q-TOF MS提供的精确质量数定性,利用TargetMS/MS提供的二级质谱碎片离子定性,对禁用合成色素进行准确定性,对常见限用合成色素进行定量,检测方法的6种常见色素加标回收率均在80%以上。此外,对这些色素软电离裂解规律进行初步研究。     

SPE-UPLC-MS/MS测定纺织品中8种有机磷酸酯阻燃剂

建立了固相萃取-超高效液相-串联质谱联用法(SPE-UPLC-MS/MS)同时测定纺织品中8种有机磷酸酯阻燃剂(OPEs)的分析方法。样品用甲醇超声提取30min后,经弗罗里硅土固相萃取小柱净化后,采用Aglient Eclipse Plus C18色谱柱(3.0×100mm,1.8μm),5mmol/mL乙酸铵水溶液(0.1%的甲酸水溶液)-乙腈作为流动相梯度洗脱电喷雾正离子(ESI+)模式离子化,选择多反应检测(MRM)方式监测,串联质谱测定,外标法定量。结果显示,各目标物方法检出限在0.003~0.500mg/kg,相关系数≥0.9991,回收率为81.7%~93.5%,RSD%为1.5%~3.4%。结果表明,本方法满足测定纺织品中有机磷酸酯阻燃剂的需要。     

基于HPLC-Q-TOF-MS/MS的分子网络技术快速分析夏天无生物碱

采用高效液相色谱-四极杆-飞行时间串联质谱(HPLC-Q-TOF-MS/MS)技术结合分子网络快速分析夏天无中生物碱成分.选取Tnature C18色谱柱(4.6 mm×250 mm×5 μm),以乙腈-0.5％甲酸为流动相进行梯度洗脱,流速1 mL/min,电喷雾离子源正离子模式下(ESI+)检测.将夏天无提取物的M...     

液相色谱-串联质谱-同位素稀释法同时测定猪肉中54种药物残留

建立了应用固相萃取技术和液相色谱-串联质谱法（HPLC-MS/MS）对猪肉中磺胺类、硝基咪唑类、喹诺酮类、大环内酯类、林可酰胺类和吡喹酮共54种药物残留同时测定的方法。样品经乙腈提取,C₁₈固相萃取柱净化,液相色谱-串联质谱法检测（正离子方式,多反应监测模式）,同位素内标稀释法进行定量。方法的定量限：磺胺类和硝基咪唑类药物为1.0 μg/kg,喹诺酮类和林可酰胺类药物为2.0 μg/kg,大环内酯类药物为3.0 μg/kg,吡喹酮为0.3 μg/kg;线性良好,相关系数大于0.991;总体回收率为20.9%~121%;相对标准偏差为2.0%~19.8%。     

人尿中β_2-受体激动剂的液相色谱质谱检测

建立了人尿中11种β2受体激动剂的液相色谱质谱(LC/MS)定性分析方法,检测了人单剂量口服一种β2受体激动剂后不同时间点的尿样。尿样经β葡萄糖苷酸酶酶解、BondElutCertify小柱提取后,采用AgilentZorbaxSBC18柱分离,以(A)0.01mol/L甲酸铵缓冲液(pH3.5)(B)乙腈为流动相进行梯度洗脱,洗脱程序:0min时,A为95%,B为5%;8min时,A为45%,B为55%;13min时,A为10%,B为90%,并保持6min。通过液相色谱质谱以选择离子监测(SIM)方式检测,测得11种药物的检测限为0.1～60.0μg/L。采用所建立的方法对人单剂量口服治疗量特布他林、克仑特罗、丙卡特罗、福莫特罗、非诺特罗或马布特罗后不同时间点的尿样进行了检测,结果表明检测口服给药48h内尿中的相应药物,信噪比可达4以上。     

SPE-UPLC-Q-TOF MS测定育发化妆品中人参和甘草类功效成分

建立了甲醇超声提取,阴离子交换固相萃取(SPE)净化,超高效液相色谱-四极杆飞行时间质谱法(UPLC-Q-TOF MS)测定育发化妆品中3种人参皂甙(Rg1、Rb1、Re)和2种甘草类功效成分(甘草次酸和光甘草定)。样品采用甲醇超声提取,MAX(500g/6L)固相萃取小柱净化,以甲醇-0.002%甲酸水溶液为流动相,梯度洗脱,在色谱柱HSS T3(2.1m×100mm×1.8μm)上分离,于UPLC-Q-TOF MS负离子模式下检测。同时,对固相萃取条件和色谱-质谱条件进行了优化,并对方法学进行了验证。结果表明:5种目标化合物在5~200μg/L浓度范围内均呈良好的线性关系,线性相关系数大于0.999;方法检出限为0.03~0.1mg/kg(S/N=3);在膏霜和洗发水基质中的加标回收率为71.9%~94.2%,相对标准偏差小于15.4%(n=6);分子质量偏差小于5×10-6。该方法适用于育发化妆品(特别是表面活性剂及油脂含量高的样品)中人参皂甙和甘草类功效成分的定性定量检测。     

基于UHPLC-Q-TOF-MS/MS联合分子网络策略快速分析紫菀中肽类成分

本文建立了超高效液相色谱-四极杆-飞行时间串联质谱(UHPLC-Q-TOF-MS/MS)法联合分子网络策略快速分析紫菀中肽类成分。采用ACQUITY UPLC^? HSS T3柱(100 mm×2.1 mm×1.8μm),以乙腈-水为流动相进行梯度洗脱,在正离子模式下,收集紫菀75%乙醇提取物的MS/MS数据,并创建GNPS分子网络。根据标准品、精确相对分子质量、碎片离子等信息,共鉴定出紫菀中43个肽类成分,包括31个环肽类和12个直链肽类,其中分别有16个和8个成分可能为潜在的新型环肽类和直链肽类化合物。UHPLC-Q-TOF-MS/MS联合分子网络策略能够快速、准确、全面地鉴定紫菀中的肽类成分,可为进一步分离紫菀化学成分和研究药效物质基础提供依据。     

基于HPLC-MS/MS快速筛选阿卡波糖及其类似物的菌株

依据阿卡波糖及其类似物的质谱特征碎片,建立了高效液相色谱-串联质谱(HPLC-MS/MS)法从20种不同来源的发酵液中快速筛选阿卡波糖及其类似物产生菌.发酵液经阳离子型固相萃取柱纯化后,采用HPLC-MS/MS筛选分析.通过归纳阿卡波糖及其类似物的特征离子碎片,总结裂解途径,得出具有C7N单元化合物的共有特征碎片,并以...     

高效液相色谱-三重四级杆质谱分析尿样中芥子气小分子代谢产物

采用高效液相色谱-三重四级杆质谱(HPLC-MS/MS),对尿样中芥子气的小分子代谢产物硫二甘醇(TDG)、1-甲基亚砜-2-[2-(甲基硫醚)-乙基砜]乙烷(R6)和1,1’-砜-双[2-(甲基亚砜)乙烷](R7),进行一级质谱和二级质谱分析检测,建立了快速、高效、检测限更低的选择反应质谱检测(SRM)分析方法。该方法成功应用于禁止化学武器组织(OPCW)第二次生物医学样品演练未知尿样的分析检测,准确筛查出所有尿样中的芥子气小分子代谢产物。     

Imaging mass spectrometry

Imaging mass spectrometry combines the chemical specificity and parallel detection of mass spectrometry with microscopic imaging capabilities. The ability to simultaneously obtain images from all analytes detected, from atomic to macromolecular ions, allows the analyst to probe the chemical organization of a sample and to correlate this with physical features. The sensitivity of the ionization step, sample preparation, the spatial resolution, and the speed of the technique are all important parameters that affect the type of information obtained. Recently, significant progress has been made in each of these steps for both secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption/ionization (MALDI) imaging of biological samples. Examples demonstrating localization of proteins in tumors, a reduction of lamellar phospholipids in the region binding two single celled organisms, and sub-cellular distributions of several biomolecules have all contributed to an increasing upsurge in interest in imaging mass spectrometry. Here we review many of the instrumental developments and methodological approaches responsible for this increased interest, compare and contrast the information provided by SIMS and MALDI imaging, and discuss future possibilities.     

Accelerator mass spectrometry

In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg and even sub-mg size) and shorter measuring times (less than 1 hr). The equipment used for AMS is almost exclusively based on the electrostatic tandem accelerator, although some of the newest systems are based on a slightly different principle. Dedicated accelerators as well as older "nuclear physics machines" can be found in the 80 or so AMS laboratories in existence today. The most widely used isotope studied with AMS is 14C. Besides radiocarbon dating this isotope is used in climate studies, biomedicine applications and many other fields. More than 100,000 14C samples are measured per year. Other isotopes studied include 10Be, 26Al, 36Cl, 41Ca, 59Ni, 129I, U, and Pu. Although these measurements are important, the number of samples of these other isotopes measured each year is estimated to be less than 10% of the number of 14C samples.     

Note: Integration of trapped ion mobility spectrometry with mass spectrometry

The integration of a trapped ion mobility spectrometer (TIMS) with a mass spectrometer (MS) for complementary fast, gas-phase mobility separation prior to mass analysis (TIMS-MS) is described. The ion transmission and mobility separation are discussed as a function of the ion source condition, bath gas velocity, analysis scan speed, RF ion confinement, and downstream ion optical conditions. TIMS mobility resolution depends on the analysis scan speed and the bath gas velocity, with the unique advantage that the IMS separation can be easily tuned from high speed (~25 ms) for rapid analysis to slower scans for higher mobility resolution (R > 80).     

Structural investigation of bacterial lipopolysaccharides by mass spectrometry and tandem mass spectrometry

Mass spectrometric studies are now playing a leading role in the elucidation of lipopolysaccharide (LPS) structures through the characterization of antigenic polysaccharides, core oligosaccharides and lipid A components including LPS genetic modifications. The conventional MS and MS/MS analyses together with CID fragmentation provide additional structural information complementary to the previous analytical experiments, and thus contribute to an integrated strategy for the simultaneous characterization and correct sequencing of the carbohydrate moiety. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 29:606–650, 2010     

Mass spectrometry of oligosaccharides

Glycosylation is a common post-translational modification to cell surface and extracellular matrix (ECM) proteins as well as to lipids. As a result, cells carry a dense coat of carbohydrates on their surfaces that mediates a wide variety of cell-cell and cell-matrix interactions that are crucial to development and function. Because of the historical difficulties with the analysis of complex carbohydrate structures, a detailed understanding of their roles in biology has been slow to develop. Just as mass spectrometry has proven to be the core technology behind proteomics, it stands to play a similar role in the study of functional implications of carbohydrate expression, known as glycomics. This review summarizes the state of knowledge for the mass spectrometric analysis of oligosaccharides with regard to neutral, sialylated, and sulfated compound classes. Mass spectrometric techniques for the ionization and fragmentation of oligosaccharides are discussed so as to give the reader the background to make informed decisions to solve structure-activity relations in glycomics.     

Electrospray mass spectrometry of phospholipids

Phospholipids play a central role in the biochemistry of all living cells. These molecules constitute the lipid bilayer defining the outer confines of a cell, but also serve as the structural entities which confine subcellular components. Mass spectrometry has emerged as a powerful tool useful for the qualitative and quantitative analysis of complex phospholipids, including glycerophospholipids and the sphingolipid, sphingomyelin. Collision induced decomposition of both positive and negative molecular ion species yield rich information as to the polar head group of the phospholipid and the fatty-acyl substituents esterified to the glycerophospholipid backbone. This review presents the current level of understanding of the mechanisms involved in the formation of various product ions following collisional activation of molecular ion species generated by electrospray ionization of the common glycerophospholipids, including phosphatidic acid, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol, phosphatidylserine, cardiolipin, and sphingomyelin. Recent advances in the application of matrix assisted laser desorption ionization is also considered. Several applications of mass spectrometry applied to phospholipid analysis are presented as they apply to physiology as well as pathophysiology.     

Applications of pulsed ultrafiltration-mass spectrometry

Pulsed ultrafiltration-mass spectrometry (PUF-MS) is a method with a variety of uses for the discovery and development of biologically active small molecules, including the screening of combinatorial libraries and natural product extracts for biologically active compounds, investigation of thermodynamic and kinetic ligand-receptor binding parameters, high-throughput metabolic screening, and the screening of combinatorial libraries and botanical extracts for electrophilic metabolites. Solution-phase ligand-screening assays that use pulsed ultrafiltration-mass spectrometry are useful for "reverse pharmacology" studies in which a macromolecular receptor of interest has been isolated, but ligands for the receptor are needed. Protein-binding studies that involve pulsed ultrafiltration can be used to rapidly determine classical binding parameters for interactions between a macromolecular receptor and a compound of interest. Metabolic screening assays can identify substrates for cytochromes p450, and should be capable of characterizing phase I metabolites with a throughput of at least 60 compounds/hr. Pulsed ultrafiltration can also be used in conjunction with LC-MS-MS to screen mixtures for compounds that might be activated metabolically to electrophilic quinoid and epoxide metabolites by cytochrome p450; that screening can provide early warning of compounds likely to be toxic when administered in large doses. The combination of pulsed-ultrafiltration extraction and mass spectrometric detection provides the sensitivity and selectivity necessary to characterize compounds present at low concentrations in complex chemical mixtures, and is applicable to the analysis of biologically active compounds from combinatorial libraries and botanical extracts.     

Orthogonal acceleration time-of-flight mass spectrometry

The principles and applications of time-of-flight mass spectrometry involving instruments with independent (orthogonal) axes for ion generation and mass analysis are reviewed. This approach, generally referred to as orthogonal acceleration time-of-flight mass spectrometry, has proved particularly advantageous for the combination of continuous ionization sources with time-of-flight mass spectrometry. The history of the technique is briefly discussed along with the instrumental principles pertaining to all the stages of the instrumentation from ion source to detector. The applications of commercial and customized instruments are discussed for several ionization methods including electrospray, matrix assisted laser desorption/ionization, electron ionization, and plasma ionization.