U型迁移谱分析器中调控漂移气体组分的效果研究

离子迁移谱-质谱联用技术已经逐渐成为对复杂混合物进行源后分离、分析的重要手段。在离子迁移谱中,漂移气体的选择或组分配比(N₂、He、CO₂等)通常会对不同类别化合物的分离度以及不同质量范围的离子通率产生影响。U型迁移谱分析器(UMA)是一种基于逆流迁移谱分析方法的独特离子迁移谱装置,特定迁移率离子可以在电场和气流的共同作用下得到精确分选。UMA具有独立的漂移气体快速进入及脱离通道,可以实时有效地完成精确调节漂移气体组分的任务。本工作研究了在UMA中使用多种漂移气体种类及不同成分配比对系统灵敏度、分离能力以及分析速度的影响,同时探讨了在单次采集过程中动态调整气体成分的可能性和优势。     

A device for the preliminary separation of ions for mass spectrometry analysis

A device for the preliminary separation of ions based on an ion mobility increment spectrometer with cylindrical geometry of its electrodes is described. The device is operated in tandem with an atmospheric-pressure ionization mass spectrometer. The use of the spectrometer in the preliminary separation of ions of the target substance from ions of the chemical noise is illustrated by investigating the vapor above a water solution of acrylamide (CH₂=CH-CO-NH₂) with a concentration of 1.4 × 10⁻⁵ mol/L. The resolution of the device is rather low, R ∼ 10–20; nevertheless, thanks to its simplicity and availability, the device may find application to routine chemical analysis and in portable instruments.     

蛋白质立体化学修饰的离子淌度质谱研究进展

蛋白质立体化学修饰是一类低丰度、与人类多种疾病相关的翻译后修饰,由于其并未改变蛋白质的分子质量,难以通过传统的蛋白组学鉴定方法进行发现与鉴定。离子淌度质谱(IM-MS)技术依据不同离子在漂移管中与缓冲气体碰撞后迁移速率的不同而快速分离离子,提供了一种基于构象、电荷数、尺寸和分子质量的分离手段,已在蛋白质立体化学修饰的鉴定与分离分析中取得了阶段性进展。本文从非变性离子淌度质谱实验的角度出发,介绍了漂移管离子淌度仪、行波离子淌度仪、微分迁移率分析仪、高场不对称离子淌度仪以及捕获离子淌度仪等5种商业化离子淌度仪的性能。在此基础上,总结了立体化学修饰高分辨离子淌度质谱分离分析与鉴定方法的最新研究进展,同时介绍了立体化学修饰调控的配体-受体相互作用的结构质谱表征策略,尤其对碰撞诱导去折叠技术在复合物手性构象差异中的研究进行阐述。最后,展望了基于IM-MS的立体化学修饰鉴定与定量等研究方向,以期为立体化学修饰的下一发展阶段提供参考。     

Determination of dioxins/furans and PCBs by quadrupole ion-trap gas chromatography-mass spectrometry

The versatility and sensitivity of the quadrupole ion trap tandem mass spectrometer has been applied to the determination of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs), and of polychlorinated biphenyls (PCBs). A brief introduction to the theory of ion confinement in a quadrupole ion trap permits discussion of ion trajectory stability, mass-selective ion ejection, the frequencies of ion motion, and the role of resonant excitation of ion motion. The tandem mass spectrometric examination of PCDDs and PCDFs eluting and co-eluting from a gas chromatographic column is described. Illustrative examples are given of the analysis of field samples containing PCDDs and PCDFs. A comparison is presented of the performance of each of a quadrupole ion trap tandem mass spectrometer, a triple stage quadrupole mass spectrometer, and a sector instrument of relatively high mass resolution for the determination of PCDDs and PCDFs. This comparison is made with respect to instrument tuning, calibration plots, detection limits, ion signals at low concentration, relative response factors, ionization cross-sections, and the examination of field samples. The application of quadrupole ion trap tandem mass spectrometry to the examination of PCBs is focused upon those PCB congeners that have the greatest toxicity. 39 congeners of the total of 209 PCB congeners have been identified as having the greatest toxicities. Chemical ionization has been used for the determination of co-eluting congeners #77 and #110 where the toxicity of the former is much greater than that of the latter. An analytical protocol, based on the variation of molecular ion fragmentation according to the degree (or absence) of chlorine ortho-substitution, has been proposed for distinguishing between toxic and nontoxic PCB congeners.     

基于高场非对称离子迁移谱的糖类异构体分离研究

本工作研发了一款配套滤波算法及重叠峰分离算法、可独立使用的平板型高场非对称离子迁移谱(FAIMS)系统,能够在分离不同离子、有效滤噪的同时,从重叠峰中准确、快速提取分析物峰,由此实现物质的精准定性分析。通过评估该FAIMS装置对糖类异构体的分离效果,发现FAIMS能有效分离出蔗糖离子的2种结构,证明其对离子结构差异更加敏感。采用氮气、氦气的混合气体作为载气,可进一步提高FAIMS的分辨力。当氦气比例达到40%时,蔗糖峰和麦芽糖峰的重合度由纯氮气时的77%降低至50%。本研究表明,该FAIMS系统可为同分异构体的定性分析提供一种新方法。     

Neptune多接收器等离子体质谱精确测定锶同位素组成

报道了近两年来在Neptune多接收器等离子体质谱(MC-ICP-MS)上对NIST SRM987的测试结果。针对实际地质样品,Neptune MC-ICP-MS和热电离质谱(TIMS)进行了平行测定。Neptune MC-ICP-MS可以精确测定锶同位素组成,与传统的TIMS相比,MC-ICP-MS可以获得与TIMS相媲美的数据精度,而且分析时间短,效率高。对于等离子体载气———氩气中少量氪的干扰,可以直接扣除;对于样品中少量铷(Rb/Sr<0.01)的干扰,同样可以直接扣除,从而获得准确的锶同位素组成。     

基于傅里叶变换-离子回旋共振质谱的离子碰撞截面测量方法及应用

傅里叶变换-离子回旋共振质谱(FT-ICR MS)具有较高的分辨率和串联质谱分析能力。离子在分析池中做回旋运动时,镜像电流会因离子与中性分子发生碰撞而逐渐衰减。基于此,通过选择合适的理论模型,并结合相应的算法,可推算出离子的碰撞截面(CCS)。该方法无需增加仪器硬件成本,可通过直接分析高分辨质谱数据获取离子结构信息。近年来,随着FT-ICR MS仪器的发展和推广,该方法得到快速发展。本文综述了此类方法使用的碰撞模型、利用时域和频域信号进行数据分析的不同方法及特点,虽然提供的离子CCS数据的可靠性和准确度有待进一步提高,但在离子的动态CCS测量以及离子异构化的研究中表现出独特优势。该方法可进一步与离子淌度技术相结合,借助FT-ICR MS较高的质量分辨能力和离子操控能力,提供多维度的离子结构信息。     

气相色谱与离子迁移谱仪联用的研究

气相色谱(Gas Chromatography)与离子迁移谱(Ion Mobility Spectrometry)的联用技术利用GC突出的分离特点和IMS快速响应、高灵敏度的优势有效地解决了GC低鉴别能力和IMS对混合物进行检测时存在的交叉灵敏度(cross sensitivity)问题,最后得到保留时间、漂移时间和信号强度的三维谱图,使定性分析更加准确。重点介绍GC-IMS联用技术的原理和优势,接口实现方法和主要影响因素,早期发展情况,存在主要问题和研究现状。     

Interfacing an aspiration ion mobility spectrometer to a triple quadrupole mass spectrometer

This article presents the combination of an aspiration-type ion mobility spectrometer with a mass spectrometer. The interface between the aspiration ion mobility spectrometer and the mass spectrometer was designed to allow for quick mounting of the aspiration ion mobility spectrometer onto a Sciex API-300 triple quadrupole mass spectrometer. The developed instrumentation is used for gathering fundamental information on aspiration ion mobility spectrometry. Performance of the instrument is demonstrated using 2,6-di-tert-butyl pyridine and dimethyl methylphosphonate.     

High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH(3).     

Note: Design and construction of a simple and reliable printed circuit board-substrate Bradbury-Nielsen gate for ion mobility spectrometry

A less laborious, structure-simple, and performance-reliable printed circuit board (PCB) based Bradbury-Nielsen gate for high-resolution ion mobility spectrometry was introduced and investigated. The gate substrate was manufactured using a PCB etching process with small holes (Φ 0.1 mm) drilled along the gold-plated copper lines. Two interdigitated sets of rigid stainless steel spring wire (Φ 0.1 mm) that stands high temperature and guarantees performance stability were threaded through the holes. Our homebuilt ion mobility spectrometer mounted with the gate gave results of about 40 for resolution while keeping a signal intensity of over 0.5 nano-amperes.     

基于电喷雾电离源质谱仪系统的八电极线性离子阱性能研究

八电极线性离子阱在前期的理论模拟研究中取得了较好的质量分析性能,为验证理论模拟结果,选择其中最优的结构参数,设计、加工并组装了八电极线性离子阱实物,以此为基础搭建电喷雾电离源质谱测试系统。在传统射频电压施加模式下,测试八电极线性离子阱的分析性能。当扫描速度为765 u/s时,八电极线性离子阱获得离子峰的半峰宽可达0.3 u,对应利血平（m/z 609）的质量分辨率为2 030。当分析浓度为10 mg/m3的利血平样品时,对应的质谱峰信噪比可达45.8。本文进一步研究了扫描速度对质量分辨率和灵敏度的影响,实现了离子碰撞诱导解离,分析了不同浓度的25羟基维生素D2标准样品,线性动态范围可达4个数量级。结果表明,八电极线性离子阱具有良好的分析性能,可为结构简化线性离子阱的研究提供全新思路,推动小型化离子阱质谱仪的研究进展。     

一种在线监测快速过程质谱仪的设计与测试

工业生产过程中,如何实现准确、连续、可靠地检测目标组分是产物及排放物在线监测的重点。本工作研制了一种在线监测快速过程质谱仪,采用高增益的复合跨导线性放大技术代替传统的过程质谱仪所采用的对数放大技术,该技术可实现质谱仪在高增益条件下仍然具有超高速的特点,结合16位高速AD转换器,可以实现更快的扫描速度和更高的数据输出频率,能够更准确地捕捉快速反应（如热解）过程的气体生成物随时间的变化信息,进而实现反应特性的精准分析和量化,为反应动力学研究提供无失真的在线分析数据。本实验对该仪器的质量分辨率、灵敏度、质量轴稳定性、长时稳定性等关键技术指标进行了测试,同时结合煤热解反应过程监控需求进行了实际应用测试。结果表明,该仪器各项指标已基本达到市场主流过程质谱仪器的水平。     

SYNAPT G2 HDMS高清质谱性能特点及应用简介

SYNAPT~(TM) G2 HDMS质谱分析系统是沃特世公司第二代基于高效离子淌度(ion mobility spectrometry,IMS,也称离子迁移)技术的高性能四极杆-飞行时间质谱仪。通过两种技术的结合与升级,SYNAPT G2 HDMS不仅能按离子的质荷比分离检测,还可根据离子的大小、形状等将其分离。因此,此质谱系统不但可以提高传统质谱数据的准确性,更可以提供样品形态信息,从而得到样品活性、结构状态等信息。其在蛋白组学、代谢组学、糖及脂类分析、医学标志物发掘、药物开发与质控、食品安全检测、环境安全检测等方面有着广泛的应用空间,并已经表现出良好的性能优势,成为各领域工作者的有力的分析工具。本文简要介绍该系统的性能特点及应用。     

辉光放电质谱仪Element GD的应用

A newest high resolution glow discharge mass spectrometer (HR-GD-MS) was developed by Thermo Electron Bremen Manufactory. Combine of a glow discharge ion source with a successful high resolution mass spectrometer, Element GD become the ultimate tool for direct analysis of conductive materials. Every part of Element GD: GD ion source, mass spectrometer, detection system and software are designed for high throughput analysis: measure 50 elements at less than 10-9 within 5 minutes. Application in microelectronics, aerospace, medical/pharmaceutical/food and nuclear will be shown.     

离子迁移谱技术及其在生命分析化学中应用

离子迁移谱技术是一种气相环境下的电泳检测技术,具有快速、灵敏、运行成本低等特点。作为一种重要的痕量化学物质检测技术,现已广泛应用于化学毒剂探测和机场、海关的毒品与爆炸物检测。近年来,离子迁移谱技术与电喷雾和基质辅助解吸附等离子化技术的结合,以及与质谱技术的联用,使得该技术的应用迅速拓展到生物医学领域。本文介绍离子迁移谱技术的主要原理并综述离子迁移谱技术在蛋白质化学、临床化学和药物化学等方面的应用。     

Combining high mass resolution and velocity imaging in a time-of-flight ion spectrometer using pulsed fields and an electrostatic lens

We describe a momentum resolving time-of-flight ion mass spectrometer that combines a high mass resolution, a velocity focusing condition for improved momentum resolution, and field-free conditions in the source region for high resolution electron detection. It is used in electron-ion coincidence experiments to record multiple ionic fragments produced in breakup reactions of small to medium sized molecules, such as F(3)SiCH(2)CH(2)Si(CH(3))(3). These breakup reactions are caused by soft x rays or intense laser fields. The ion spectrometer uses pulsed extraction fields, an electrostatic lens, and a delay line detector to resolve the position. Additionally, we describe a simple analytical method for calculating the momentum from the measured hit position and the time of flight of the ions.     

地球科学中热电离质谱法的进展

对应用于地球科学领域的几种热电离质谱新方法的进展进行了综述,包括Sr、Nd同位素稀释分析的分馏校正、Re—Os负离子质谱法、热电离质谱铀系法、B、Cl稳定同位素测定及La—Ce法。     

Development of two-grating spectrometer for the charge exchange spectroscopy system on KSTAR

The charge exchange spectroscopy (CES) system on Korea Superconducting Tokamak Advanced Research (KSTAR) was installed last year and had been applied to measure the C VI ion temperature and rotation velocity profiles. The ion temperature and rotation velocity profiles had been estimated from the C VI 5290.5 ? (n = 8-7) charge-exchange spectrum signal measured by a Czerny-Turner type spectrometer and a thinned back-illuminated charge coupled device (CCD) camera. However, the Czerny-Turner type spectrometer used for the KSTAR CES system showed so low signal to noise ratio for KSTAR plasmas in the 2010 experimental campaign that the time resolution of the CES system had been limited to 100 ms due to the increased exposure time of the attached CCD camera. Then, new two-grating spectrometer had been developed in order to improve the time resolution of the CES system. The spectrometer consists of two gratings (1200 g/mm and 1800 g/mm each) with additive configuration, concave mirrors (f = 50 cm), and a cylindrical lens (f = 50 cm). The time resolution of the CES system increases by a factor of 2-4 with the two-grating spectrometer. The C VI ion temperature and rotation velocity profiles obtained by the two-grating spectrometer are compared to those by Czerny-Turner type spectrometer in this paper.