SUPERSONIC JET EXPANSIONS OF SUPERCRITICAL FLUIDS

本文提出了一种新的、高选择性的分析非挥发性化合物的方法 或热不稳定材料。 这种方法将四个人聚集在一起， 技术：超声射流光谱，激光多光子电离， 质谱法和超临界流体色谱法。 样品将 溶解在超临界流体中并在超音速射流中膨胀， 与质谱仪相连 分子的等熵冷却 在膨胀过程中产生了强烈的紫外-可见光 允许目标化合物的选择性激光电离的吸收带 共振增强多光子电离。 此方法应该 特别适用于测定对环境重要的氯， 羟基和大芳族化合物的胺衍生物， 生物学上重要的嘌呤、嘧啶和生物碱 样品 除了分析应用外，该方法还应提供 一种新的研究低温光谱和动力学的方法， 非挥发性极性材料。 射流膨胀的基本方面 将对接口进行研究，以优化性能。

A new, highly selective method is proposed for the analysis of nonvolatile or thermally labile materials. This method brings together four individual techniques: supersonic jet spectroscopy, laser multiphoton ionization, mass spectrometry, and supercritical fluid chromatography. Samples will be dissolved in a supercritical fluid and expanded in a supersonic jet which is interfaced to a mass spectrometer. Isentropic cooling of molecules during the course of the expansion produces sharp ultraviolet-visible absorption bands allowing selective laser ionization of targeted compounds by resonantly enhanced multiphoton ionization. This method should be especially useful in the determination of environmentally important chloro, hydroxyl, and amine derivatives of large aromatic compounds and of biologically important purines, pyrimidines, and alkaloids in complex samples. In addition to analytical applications, the method should provide a new way of investigating the low temperature spectroscopy and dynamics of nonvolatile polar materials. Fundamental aspects of the jet expansion interface will be studied in an effort to optimize performance.