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Project Progress

The field of ambient mass spectrometry has developed rapidly over the past decade. The ability to rapidly perform chemical analysis with minimal sample handling and preparation is key to the success of many ambient ionization sources, with small size and versatility in sampling a wide variety of organics with varying molecular properties being two desired features. The two most widely applied ambient sources are desorption electrospray ionization (DESI) and its variants, and direct analysis in real time (DART). We have developed a compact DART source (mini-DART), shown in Figure 1, that has proven to be extremely successful in analyzing complex organic mixtures. In this work we utilize the mini-DART ionization source for the analysis of complex organic mixtures with the goal of showcasing the abilities of this newly designed source and its multiple applications. These analyses include the characterization of Titan organic stimulants produced by Ames’ Cosmic Simulation Chamber (COSmIC) with various gas mixtures representative of Titan’s atmosphere. To demonstrate sampling of a mixture with wide ranging volatility, polypropylene glycol, the mini-DART gas temperature is systematically increased to observe higher molecular weight components in the sample (Figure 2). This methodology is also applied to the analysis of hydrocarbons, with La Brea Tar Pits Asphalt acting as a representative sample. Again, increase in gas temperature results in detection of increasingly higher molecular weight components, indicating that thermal analysis can provide greater insight into the composition of complex samples.