SUPERSONIC JET EXPANSIONS OF SUPERCRITICAL FLUIDS

提出了一种新的、高选择性的非挥发性物质分析方法。 或热不稳定的材料。这种方法将四个个体集合在一起 技术：超音速喷射光谱、激光多光子电离、 质谱仪和超临界流体色谱学。样品将会是 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 在膨胀过程中产生强烈的紫外线-可见光 允许目标化合物选择性激光电离的吸收带 通过共振增强的多光子电离。此方法应为 特别适用于对环境重要的氯的测定， 大的芳香族化合物的羟基和胺的衍生物以及 复合体中具有重要生物意义的嘌呤、嘧啶和生物碱 样本。除分析应用外，该方法还应提供 低温光谱和动力学研究的一种新方法 非易失性极性材料。喷气扩张的基本方面 将对接口进行研究，以努力优化性能。

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.