Detection Technologies. Ambient mass spectrometry

A recent innovation in mass spectrometry is the ability to record mass spectra on ordinary samples, in their native environment, without sample preparation or preseparation by creating ions outside the instrument. In desorption electrospray ionization (DESI), the principal method described here, electrically charged droplets are directed at the ambient object of interest; they release ions from the surface, which are then vacuumed through the air into a conventional mass spectrometer. Extremely rapid analysis is coupled with high sensitivity and high chemical specificity. These characteristics are advantageously applied to high-throughput metabolomics, explosives detection, natural products discovery, and biological tissue imaging, among other applications. Future possible uses of DESI for in vivo clinical analysis and its adaptation to portable mass spectrometers are described.     

质谱检测技术在蜂蜜溯源分析中的应用

蜂蜜由于其丰富的营养成分以及良好的保健作用受到越来越多人的青睐。近年来,蜂蜜的质量安全问题逐渐凸显,建立蜂蜜溯源体系可对蜂蜜的质量安全隐患进行识别、预防和控制,具有十分重要的现实意义。溯源检测技术在蜂蜜溯源体系中起到了极为重要的技术支持作用。根据国内外蜂蜜溯源分析发展现状和实际,结合稳定同位素质谱法、高效液相色谱-质谱法、气相色谱-质谱法和等离子体发射光谱-质谱法等先进的质谱分析方法,着重阐述了质谱检测技术在蜂蜜溯源分析中的研究进展,并对未来蜂蜜溯源分析检测技术的发展趋势和应用前景提出了一些观点和看法。     

Fast atom bombardment mass spectrometry

Fast atom bombardment mass spectrometry has become a powerful structural tool since the first reports of its use in 1981. Samples are ionized in the condensed state, usually in a glycerol matrix, by bombarding the matrix with xenon or argon atoms with energies of 5000 to 10,000 electron volts. This yields both positive and negative secondary ions, which are sputtered from the surface. The technique has been used to detect inorganic ion clusters to mass 25,800 and biologically active peptides to mass 5700, and it gives molecular ions of such highly polar or labile organic compounds as glycosphingolipids and polyene antibiotics. It can be especially valuable in determining the sequences of amino acids in polypeptides.     

Mass spectrometry: analytical capabilities and potentials

The mass range of mass spectrometers has been extended by almost an order of magnitude in the past decade, ionization procedures have been introduced which allow ionic, nonvolatile compounds to be examined, and new capabilities have been achieved through the successful integration of separation and analysis techniques. In combination with other techniques, mass spectrometry has been used in biological and environmental research to characterize constituents of mixtures, including those present in trace amounts; in metabolic profiling, where high throughput and large dynamic range are important; and in protein structure determinations. Measurements of stable isotope abundances by mass spectrometry have been used in enzymology, studies of photosynthesis, and carbon dating. Outside the area of chemical analysis, mass spectrometry has been used to study gas-phase acidities and basicities and to study organic reaction mechanisms in the gas phase. Trends in mass spectrometry include multidimensional experiments, use of ionization methods, direct analysis without extensive sample preparation, and the development of advanced instrumentation including an ion trap and an inductively coupled plasma mass spectrometer. It is likely that mass spectrometry will come to be much more widely used and that data will increasingly be other than conventional mass spectra.     

拟除虫菊酯类农药残留分析方法研究进展

综述了拟除虫菊酯类农药残留的分析技术及其研究进展。介绍了样品前处理方法如固相萃取、超临界流体萃取、基质固相分散苹取、加速溶剂萃取等在拟除虫菊酯类农药残留分析中的应用;阐述了气相色谱、液相色谱及其联用技术用于样品中拟除虫菊酯农药残留的检测;并展望了该领域的发展趋势。     

Ion beam spectroscopy of solids and surfaces

Ion beams are important new probes for characterizing the chemistry and structure of a wide variety of materials. When beams of particles with energies of approximately 1000 electron volts are used, as in secondary ion mass spectrometry, it is possible to detect ions ejected from the top layer of the material with sensitivities we below the picogram level. A number of theoretical developments now permit analysis of the geometry of adsorbed atoms and molecules on surfaces from the angular distributions of the ejected particles. Much surface chemical information can also be deduced from ejected molecular cluster ions. In addition, the observation of clusters with weights up to nearly 20,000 atomic mass units promises to expand applications of mass spectrometry to the analysis of biomolecules and the sequencing of proteins.     

Accelerator mass spectrometry for measurement of long-lived radioisotopes

Particle accelerators, such as those built for research in nuclear physics, can also be used together with magnetic and electrostatic mass analyzers to measure rare isotopes at very low abundance ratios. All molecular ions can be eliminated when accelerated to energies of millions of electron volts. Some atomic isobars can be eliminated with the use of negative ions; others can be separated at high energies by measuring their rate of energy loss in a detector. The long-lived radioisotopes (10)Be, (14)C,(26)A1, 36Cl, and (129)1 can now be measured in small natural samples having isotopic abundances in the range 10(-12) to 10(- 5) and as few as 10(5) atoms. In the past few years, research applications of accelerator mass spectrometry have been concentrated in the earth sciences (climatology, cosmochemistry, environmental chemistry, geochronology, glaciology, hydrology, igneous petrogenesis, minerals exploration, sedimentology, and volcanology), in anthropology and archeology (radiocarbon dating), and in physics (searches for exotic particles and measurement of halflives). In addition, accelerator mass spectrometry may become an important tool for the materials and biological sciences.     

高分辨质谱在农药残留领域中的应用分析

高分辨质谱是一种将样品经色谱和部分质谱分离与离子化，再经质谱检测器得到的图谱实现对已知或未知物质的定性、定量分析技术。因其高通量、分析速度快、灵敏度、分辨率高等特点，近年被广泛运用在农药残留检测中。本文综述了近些年高分辨质谱技术在农药残留领域中的研究进展，并对其未来发展进行展望，旨在为今后相关人员检测农药残留提供参考。     

Primary sequence information from intact proteins by electrospray ionization tandem mass spectrometry

Tandem mass spectrometry has been used to obtain information related to portions of the primary sequence for an intact protein, bovine ribonuclease A. Multiply charged molecular ions, generated by electrospray ionization, were collisionally dissociated at low energies in a triple quadrupole mass spectrometer to yield singly and multiply charged fragment ions that can be assigned to the known sequence of the protein. Dissociation of the highly charged molecular ions resulted in pairs of complementary product ions. The higher order (gas-phase) protein structure affects the dissociation processes, as observed in comparisons of tandem mass spectra of the native and disulfide-reduced forms of ribonuclease A.     

纳米二次离子质谱技术(NanoSIMS)在微生物生态学研究中的应用

超高分辨率显微镜成像技术与同位素示踪技术相结合的纳米二次离子质谱技术(NanoSIMS)具有较高的灵敏度和离子传输效率、极高的质量分辨率和空间分辨率(＜ 50 nm),代表着当今离子探针成像技术的最高水平.利用稳定性或者放射性同位素在原位或者微宇宙条件下示踪目标微生物,然后将样品进行固定、脱水、树脂包埋或者导电镀膜处理,制备成可供二次离子质谱分析的薄片,进一步通过NanoSIMS成像分析,不仅能够在单细胞水平上提供微生物的生理生态特征信息,而且能够准确识别复杂环境样品中的代谢活跃的微生物细胞及其系统分类信息,对于认识微生物介导的元素生物地球化学循环机制具有重要意义.介绍了纳米二次离子质谱技术的工作原理和技术路线,及其与同位素示踪技术、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、荧光原位杂交技术(FISH)、催化报告沉积荧光原位杂交技术(CARD-FISH)、卤素原位杂交技术(Halogen In Situ Hybridization,HISH)等联合使用在微生物生态学研究方面的应用.     

基质辅助激光解析电离飞行时间质谱仪在家蚕蛋白质组中的应用

随着家蚕基因组全序列框架图的完成,家蚕蛋白质组学研究也就成了当前家蚕研究的主要方向之一。而双向电泳技术和质谱技术的发展为大规模研究家蚕蛋白质组提供了强有力的平台。近年来,基质辅助激光解析电离飞行时间质谱在蛋白质组学研究中的应用日益广泛,为此着重对其在家蚕蛋白质组学研究中的应用进行探讨。     

农产品中农药残留分析技术研究进展

农药残留的极性中毒事件和农产品进出口贸易中农药残留超标问题时有发生,农药残留分析是保证人民群众食品安全和进出口企业利益的重要手段,近年来农产品中农药残留分析技术有了快速的发展。本文主要在农药残留分析中的样品前处理和仪器检测2方面对近5年来的研究进展进行分析和讨论,主要探讨了前处理中的QuEChERS方法的应用、改进和发展,以及仪器检测手段中串联质谱的应用现状及高分辨质谱的应用前景,最后对农药残留分析这两方面的发展进行了展望。     

Inertial confinement fusion with light ion beams

The Particle Beam Fusion Accelerator II (PBFA II) is presently under construction and is the only existing facility with the potential of igniting thermonuclear fuel in the laboratory. The accelerator will generate up to 5 megamperes of lithium ions at 30 million electron volts and will focus them onto an inertial confinement fusion (ICF) target after beam production and focusing have been optimized. Since its inception, the light ion approach to ICF has been considered the one that combines low cost, high risk, and high payoff. The beams are of such high density that their self-generated electric and magnetic fields were thought to prohibit high focal intensities. Recent advances in beam production and focusing demonstrate that these self-forces can be controlled to the degree required for ignition, break-even, and high gain experiments. ICF has been pursued primarily for its potential military applications. However, the high efficiency and cost-effectiveness of the light ion approach enhance its potential for commercial energy application as well.     

蛋白质组学技术的研究与应用

蛋白质组学(Proteomics)是一门相对于基因组学(Genomics)而提出的,旨在综合研究某一基因组所表达的全部蛋白质的新型学科.蛋白质组学在生物学中的应用越来越广泛,依赖于蛋白质组学技术如二维电泳(2-DE)、高效液相色谱(HPLC)、质谱以及生物信息学等获得快速发展和逐渐成熟,综述了蛋白质组学技术的研究与应用.     

色谱-质谱联用技术在真菌毒素检测中的研究进展

真菌毒素是一类真菌产生的次级代谢产物,在自然界中分布极为广泛,严重危害人畜健康,污染食品、农产品及药用植物等.由于真菌毒素含量较低,普通方法难以准确测定,色谱-质谱技术由于其灵敏度高、前处理相对简单,结果准确可靠,在检测真菌毒素方面前景广阔.对色谱-质谱联用技术在真菌毒素检测中的应用研究进展进行了综述,并对其在药用植物真菌毒素检测中的应用前景进行了展望.     

苏云金芽孢杆菌的概况及其研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫剂是对人和环境友好的安全型细菌杀虫剂。目前Bt杀虫剂已被广泛应用,但因使用剂量较大,导致防治害虫时费用过高。若在生物防治中使用超高效的细菌杀虫剂,就可降低其使用剂量。Bt 00-50-5菌株是从美国引进的高效杀虫菌株,其晶体蛋白的特征分析尚未完成,其毒素的作用机理研究也未进行。本项目即将开展如下研究:(1)先用具有特异性杀虫功能的Bt 00-50-5菌株进行发酵,继续完成对防治中国害虫防治效果的评价;再分析细菌的编码杀虫毒素基因和毒素的生化特征;然后混合荧光标记毒素和中肠细胞,加入昆虫中肠蛋白酶(或单独加入氨肽酶、碱性磷酸酶、ATP酶、枯草杆菌蛋白酶、钠或钾离子代之)反应,用荧光显微镜观察细胞变化;最后阐明杀虫毒素对靶标细胞作用机制。(2)通过研究毒素分子与受体分子的作用关系,拟在分子水平上阐明毒素的作用机制。     

An ion balance for ultra-high-precision atomic mass measurements

We have developed the analog of a double-pan balance for determining the masses of single molecular ions from the ratio of their two cyclotron frequencies. By confining two different ions on the same magnetron orbit in a Penning trap, we balance out many sources of noise and error (such as fluctuations of the magnetic field). To minimize the systematic error associated with the Coulomb interaction between the two ions, they are kept about 1 millimeter apart from each other, resulting in fractional uncertainty below 1 x 10(-11). Such precision opens the door to numerous applications of mass spectrometry, including metrology, fundamental physics, and weighing chemical bonds.     

Extraction and analysis of organic cations from Acid solution with strong electric fields and mass spectrometry

High electric fields have been used to extract organic cations from solutions of small organic molecules in polyphosphoric acid. The cations have been analyzed by mass spectrometry. Production of ions by this method is shown to be related to ease of protonation by acid rather than to ionization potential.     

蓝花楹挥发物的ATD-GC/MS联用分析及园林芳香性评价

[目的]评价蓝花楹活体枝叶的芳香性及其在城市园林绿化中的应用价值。[方法]采用全自动热脱附-气相色谱/质谱(ATD-GC/MS)联用技术,对动态顶空密闭循环吸附捕集的蓝花楹健康活体枝叶挥发物进行检测。[结果]挥发物中可检出醚、醛、醇、酯、烃5类化合物,使逸散于空气中的总体气息表现为花果样青香,其中具有茉莉花香特点的成分可能来自醛类,该类成分种类较多、香比强值(ASV)较高,总相对含量达21.72%。[结论]由于蓝花楹挥发物中的各种成分常用于日用香料香精产品,对人体有益,因此该树种在芳香性方面适宜作为城市园林绿化植物。