New Ambient Mass Spectrometry: Advances and Applications in Organic Analysis
離質譜法及熱脫附大氣壓下質譜。前者是利用一超音波震盪器（頻率: 40 kHz）輔助樣
載樣品之平台，波長808 nm 的近紅外光雷射對著鍍有多層金奈米粒子的一面進行照射，
Ambient mass spectrometry (AMS) has lately attracted a great deal of attention because it allows for direct analyses at atmospheric pressure without any pre-treatment or with only a minimum sample preparation, offering the advantages of speed and ease-of-use. We recently explored two types of new AMS methods, i.e. ultrasonication-assisted spray ionization mass spectrometry (UASI) and thermal desorption AMS (TD-AMS). UASI MS employs a low frequency ultrasonicator (ca. 40 kHz) in place of the high electric field required for electrospray ionization. When a capillary inlet is immersed into a sample solution within a vial subjected to ultrasonication, an ultrasonic spray of the sample solution is emitted at the outlet of the tapered capillary, leading to the ready generation of gas phase ions. Additionally, layer-by-layer self-assembled multilayer of gold nanoparticle (Au NP)-based glass chip (Glass@AuNPs) with the absorption capacity in the near-infrared (NIR) region was used as the energy absorber and as the sample holder for sample deposition at ambient condition in TD-AMS. An NIR laser diode (808 nm) was successfully employed as the thermal desorption source to liberate only small molecules from Glass@AuNPs chips. The desorbed molecules are further ionized by post-ionization followed by the detection of a mass spectrometer. On the basis of these two new AMS methods, the applications in the analysis of complex samples including organic reaction products and high-salt biological fluids will be explored in this three-year project. In the first year of this proposal, it is aimed to employ the TD-AMS in the analysis of complex samples without sample pretreatment steps. The goal for the second year proposal is to explore a system based on the use of UASI MS for on-line monitoring ultrasonic-assisted organic reactions. Polymer degradations and transesterification reactions are selected as model reactions. In the third year of this proposal, a multi-spray UASI-MS system will be developed. The newly developed system is expected to have the capability of desalting during manipulating multi-spray in UASI MS. The possibility of monitoring reactions occurring during spray by multi-spray UASI MS will be also explored.
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