高分辨电喷雾离子源三级四极杆-飞行时间质谱仪的研制

报道了实验室研制的电喷雾离子源 ,具有射频四极杆接口的高分辨飞行时间质谱 (ESI- QQQ- TOFMS)仪器。该仪器具有以下特点 :在离子调制区使用三组四极杆 ,有效地减少离子束的空间分散和能量分散 ;采用正负双脉冲推斥和离子垂直引入方式 ;经过优化设计的二级有网反射器 ;新颖的 MCP安装方法。经初步调试 ,该仪器的分辨本领已优于 1 0 ,0 0 0 ,质量测定精度优于 1 0× 1 0 - 6 。该仪器于 2 0 0 2年 6月通过了国家教育部科技成果鉴定 [鉴字 [教 2 0 0 2 ]第 0 0 8号 ],其主要性能指标已经达到了国际先进水平     

大气压接口-单四极杆质谱仪的研制

本工作研制一种具有大气压接口的单四极杆质谱仪。该仪器具有三级真空系统,与大气相邻的第一级真空接口基于加热的不锈钢毛细管设计;在第二级真空腔中采用射频高压驱动的方式远距离传输离子;第三级腔体放置四极杆和电子倍增器分离和探测离子,使用自制的控制系统控制仪器。基于此仪器,实现了大气压下电喷雾离子源、介质阻挡放电离子源离子化样品的检测,通过第一级腔体中的源内碰撞诱导解离获得了样品的二级子离子,增强了单四极杆质谱仪的定性能力。该仪器结构简单、成本低,可用于液相色谱-质谱联用分析和原位分析。     

大气压基质辅助激光解析离子源高分辨飞行时间质谱仪的研制

本文介绍了实验室自制的大气压基质辅助激光解析离子源（Atmospheric Pressure Matrix—assisted Laser Desorption／Ionization，AP—MALDI）高分辨飞行时间质谱仪（Time—of—flight Mass Spectrometer，TOFMS）的原理、结构以及初步的实验结果。通过对多肽样品gramicidin S的分析，国内首次实现在自制AP—MALDI—TOFMS上得到生物大分子谱图。结果表明，AP—MALDI高分辨TOFMS可以实现大气压下大通量的大分子精确质量检测。仪器分辨率优于8000（Full Width at Haft Maximum，FWHM），最低检测限可达25fmol。     

大气压基体辅助激光解析离子源的研制及其与高分辨飞行时间质谱仪的联用

介绍了自制大气压基体辅助激光解析离子源的原理及结构.考察了该离子源与高分辨率垂直引入式飞行时间质谱仪联用后的性能.实验结果表明,仪器灵敏度、质量分辨率和精度等达到了较高水平.     

高分辨率电喷雾电离飞行时间质谱仪测定大豆磷脂中的磷脂酰胆碱

首次实现了国内用自制高分辨率电喷雾电离飞行时间质谱仪(ESI-TOF-MS)检测大豆磷脂中的磷脂酰胆碱(PC),共检测出了52种磷脂酰胆碱.实验证明,高分辨率ESI-TOF-MS具有定性速度快、灵敏度高、精确度好的优点,是目前磷脂检测的最为有效的工具.     

四极杆/飞行时间质谱/质谱仪

本文介绍了一种新型的四极杆/飞行时间质谱/质谱仪技术及其广泛的应用     

高灵敏VOCs在线真空紫外单光子电离飞行时间质谱仪的研制

研制了一种高灵敏度在线膜进样真空紫外电离源飞行时间质谱仪（MI-SPI-TOF MS）用于检测低浓度挥发性有机物（VOCs）。仪器包括真空系统、膜进样接口、真空紫外单光子电离源、垂直加速反射式飞行时间质量分析器和数据采集系统等。该仪器使用聚二甲基硅氧烷（PDMS）膜作为大气压下直接进样的接口,膜的选择透过性能直接、快速地富集大气中VOCs,可实现快速在线进样检测。真空紫外单光子灯作为电离源,能将电离能低于10.6 eV的VOCs电离,形成分子离子峰。结果表明,该仪器的分辨率优于750 FWHM,对苯、甲苯、二甲苯和氯苯的检测限达10^-12 mol/mol级别,检测速度达秒级,可用于低浓度VOCs的实时在线检测。     

图说质谱仪TRITON离子源室真空问题的解决

热电离质谱仪TRITON的离子源室真空要求极高,一旦产生漏气,会导致离子流不稳定、甚至高压打火等故障,轻则无法采集数据、仪器不能正常工作,重则损坏仪器。本文特别针对离子源室真空漏气这一常见的故障现象作了详细描述,对产生故障的原因作了多方面认真分析,此案例中确定是样品转盘的驱动轴密封性能变差产生漏气。为了节约资金及尽快使仪器恢复正常工作,决定自行拆解维修,并以图片形式记录了其维修过程。     

热电离飞行时间质谱仪性能评价

本工作介绍了实验室自制的热电离飞行时间质谱仪（TI-TOF-MS）的基本结构、仪器运行参数和性能特点等。离子源产生的离子在推斥电压作用下进入聚焦透镜,然后进入垂直引入反射式的飞行时间质量分析器,最后到达检测器。信号通过数据采集卡处理后传输给计算机,采用编写的LabVIEW软件采集信号和处理数据。结果表明：仪器可测量的质量范围为m/z 6~320,在m/z 208位置的质量分辨率可达2000,2 h质量稳定性为7.76×10^-5,测量²⁰⁷Pb/²⁰⁶Pb、²⁰⁷Pb/²⁰⁶Pb和²⁰⁷Pb/²⁰⁶Pb同位素比值的精密度分别为0.85%、0.27%和0.55%。该仪器在研究热电离离子源电离行为、同位素比值测定和多原子离子信号监测等方面具有广泛的应用前景。     

选择性电喷雾电离-质谱接口的设计

设计了一种新型电喷雾电离-质谱（ESI-MS）接口.接口对于不同动量和迁移率的离子及非带电中性粒子具有识别能力.对新型接口性能的初步考察表明,它能大幅度提高单电荷离子的传输效率,减少中性和多电荷离子进入真空系统的概率,因此能显著降低化学噪声,提高信噪比,并有利于保持系统的清洁与稳定,有望在nano-MS、HPLC-MS以及小型质谱仪器中得到应用.     

微流控芯片与电喷雾质谱联用接口的制作与应用

介绍了自制玻璃微流控芯片与电喷雾离子化质谱(ESI-MS)联用接口的制作方法。在芯片边缘直接将外接管路与管道相连，通过芯片上的旁路引入辅助液体，通过电场或压力驱动将样品送入质谱仪，实现稳定电喷雾。以芯片作为预进样平台，利用质谱检测了蛋白混合物、兴奋剂类药物混合物和中药提取物。在接口制作中，使用CB胶和保护性盖片，解决了机械加工步骤(切割、打磨和打孔等)中对微型结构的保护封装问题；在外接管路中的金属双通上施加高压电场地电势，实现了芯片管道中液体的电渗泵驱动。     

A Hadamard transform electron ionization time-of-flight mass spectrometer

We describe the first Hadamard transform time-of-flight mass spectrometer (HT-TOFMS) that incorporates an electron (impact) ionization source. This implementation was realized in an existent TOF instrument using commercially available components and simple modifications to the ion source. In the present apparatus, a Hadamard mask is expressed by modulating the ion generation process within the ion source; thus, the present approach differs from previous designs that use external electrostatic devices to modulate a continuous ion stream. The present implementation may be operated in conventional TOF mode at 12.5 kHz and in HT-TOF mode at 20-40 MHz. In Hadamard mode the design can operate using any circulant simplex code, allowing the operator much flexibility for optimizing resolution and mass range and for eliminating nonstochastic fluctuations, e.g., encoding errors and signal hum. We demonstrate typical performance of the HT-TOFMS in standard and reflectron geometries using sequences of three constructions and of varied length, generating HT-TOF mass spectra of molecules that match conventional reference spectra. The auxiliary material includes an electrical schematic for the floating high-speed encoding amplifier, which is also of use in other high-speed electrostatic optics applications, and a list of 537 validated vectors comprising the first row of each circulant simplex sequence (S(n)=3-8219) derived using maximal shift register (n=2(m)-1), quadratic residue (n=4m-3), and twin prime constructions [n=p(p+2)].     

电喷雾质谱在医药领域应用进展

电喷雾提供相对简单的方法使非挥发性的溶剂形成气态,与此同时质谱技术提供更直接、灵敏度好的检测,使电喷雾质谱在天然药物化学中天然产物的提取、药物分析中生物体内的代谢、以及生物化学中具有生理活性的多肽和蛋白质检测等方面具有优势,电喷雾质谱可以检测低浓度,得到高准确性结果。本文就近年来电喷雾质谱在医药中的应用进行综述。     

飞行时间质谱仪国内研究状况及发展趋势

本文介绍飞行时间质谱仪的发展历史,对近二十年来国内飞行时间质谱仪的研制状况做较全面的概述。最后结合国内情况,介绍飞行时间质谱仪为适应不同应用领域研究对象的需要,目前主要的两个发展方向,一个是发展超高分辨、高灵敏度的高档仪器,另一个是发展小型台式仪器。     

Ultrahigh vacuum deposition of organic molecules by electrospray ionization

An electrospray apparatus for deposition of organic molecules on surfaces in ultrahigh vacuum is presented. The kinetic energy at the impact and mass to charge ratio of deposited ions can be controlled by an electrostatic quadrupole deflector and an in-line quadrupole mass spectrometer. With an ion funnel in the first two vacuum stages a high ion transmission is achieved. Experiments on porphyrin cations and deoxyribonucleic acid deposited on a Au(111) surface demonstrate the capabilities of the instrument.     

Ion thermalization using pressure transients in a quadrupole ion trap coupled to a vacuum matrix-assisted laser desorption ionization source and a reflectron time-of-flight mass analyzer

Efficient trapping and detection of intact peptide ions is demonstrated in a quadrupole ion trap (QIT) coupled to an external vacuum matrix-assisted laser desorption ionization (MALDI) source. Deactivation of metastable ions generated by MALDI is achieved in a pressure transient environment inside the QIT established by pulsing gas to access the higher pressures required for fast thermalization, without affecting vacuum conditions in the ion source and time-of-flight (TOF) mass analyzer. Pressure transients are experimentally determined and a threshold of approximately 10 mTorr is identified where internally excited ions, which commonly observed to dissociate upon injection in a QIT, are stabilized. Fragment-free spectra are presented for a set of peptides by using 2,5-dihydroxybenzoic acid (DHB) as a matrix, and significantly reduced fragmentation is observed by using a-cyano-4-hydroxycinnamic acid (CHCA). Intact peptide spectra of a protein tryptic digest are also recorded with CHCA. The process of translational cooling for externally injected ions in a dynamic pressure environment is visualized by using ion trajectory simulations that employ hard sphere collisions. Statistical theory of dynamic equilibrium of ions stored in rf fields is applied to our QIT to characterize a translationally thermalized ion cloud, to explain observed ejection efficiency into the TOF mass analyzer, and to further discuss collisional deactivation of metastable ions.     

A hardware and software system for the laser time-of-flight mass spectrometer

The hardware and software system for a laser time-of-flight mass spectrometer is based on the double-level principle. At the upper level, the personal computer automatically controls online recording and processing of mass spectra with the highest priority. The monitoring and stabilization functions are fulfilled by controllers of the second control level. The exchange between the controllers and personal computer takes place in the periods between mass-spectrum recording and processing. The use of the hardware and software system has made it possible (i) to form short mass peaks with a half-height duration of up to 10 ns, (ii) to decrease a scatter of relative sensitivity coefficients from two or three down to one order of magnitude, and (iii) to increase a dynamic range of the recorded mass spectra up to 1?1 × 10⁹.     

电喷雾质谱新方法及在生命分析化学中的应用

电喷雾质谱是目前应用最广泛的生物质谱技术之一。复杂生物基质对质谱分析的选择性和准确性提出挑战 ,迫切需要在质谱方法学上有所发展。本文介绍具有广泛应用前景的几种电喷雾质谱新方法的原理和特点及若干应用实例 ,对生物质谱的发展趋势和在生命分析化学中的应用前景进行展望