Synchrotron radiation based aerosol time-of-flight mass spectrometry for organic constituents
Synchrotron radiation based aerosol time-of-flight mass spectrometry for organic constituents
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DOI：
10.1021/ac050440e
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发表时间：
2005-09-15
影响因子：
7.4
通讯作者：
Baer, T
中科院分区：
文献类型：
--
作者：
Mysak, ER;Wilson, KR;Baer, T
描述了一种基于同步辐射的气溶胶飞行时间质谱仪，使用可调谐真空紫外 (VUV) 战斗，用于实时分析超细和大气溶胶颗粒中的有机化合物。从大气压力中对颗粒进行采样，并通过空气动力透镜组件聚焦到质谱仪中。当颗粒进入源区域时，它们撞击筒式加热器并被蒸发。粒子蒸气膨胀回源区域，并被同步加速器辐射产生的可调谐、准连续 VUV 光轻轻电离。辐射的能量可以调节到接近样品分子的电离能，从而最大限度地减少离子碎片造成的复杂性。可以轻松收集光电离效率扫描（光子扫描），从而可以测量分子的电离能和碎片起始点。分析了大气气溶胶中四种重要的高分子量、低蒸气压有机化合物，并测量了它们的电离能，不确定度为 +/- 60 meV。它们是油酸（8.68 eV）、亚油酸（8.52 eV）、亚麻酸（8.49 eV）和胆固醇（8.69 eV）。
A synchrotron radiation based aerosol time-of-flight mass spectrometer using tunable vacuum-ultraviolet (VUV) fight is described for real-time analysis of organic compounds in ultrafine and large aerosol particles. Particles are sampled from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. As the particles enter the source region, they impinge on a cartridge heater and are vaporized. The particle vapor expands back into the source region and is softly ionized with tunable, quasicontinuous VUV light generated with synchrotron radiation. The radiation can be tuned to an energy close to the ionization energy of the sample molecules, thus minimizing the complications resulting from ion fragmentation. Photoionization efficiency scans (photon scans) can be readily collected, which permit measurement of the molecule's ionization energy and fragmentation onsets. Four high molecular weight, low vapor pressure organic compounds of importance in atmospheric aerosols are analyzed and their ionization energies measured with uncertainties of +/- 60 meV. These are oleic acid (8.68 eV), linoleic acid (8.52 eV), linolenic acid (8.49 eV), and cholesterol (8.69 eV).