A system is developed in which a sediment or soil sample is placed in an online pyrolysis device. After pyrolysis, the effluent passes through a sorption-based, online preconcentrator for analyte collection. The preconcentrator is then heated to desorb the analytes and introduce them to the GC as a narrow plug. A comprehensive 2DGC will be used to take advantage of increased peak capacity and sensitivity. Detection will be by TOFMS to obtain structural information of analytes and their pyrolysis products. Complex samples, such as polymers or kerogens, are not sufficiently volatile to analyze directly by GC. Pyrolysis is a commonly used method to fragment these large molecules into sizes that can be analyzed on a GC. The pyrolysis device in this case is a section of metal tube, containing the sample, which can be resistively heated. This pyrolysis device is placed in series with a sorption-based preconcentrator. The sorption-based preconcentrator consists of discrete beds of several different carbon-based adsorbents inside of a metal capillary tube, which is resistively heated to desorb the collected analytes. The preconcentrator is designed so that as sample flows into the tube, the first bed encountered consists of the weakest adsorbent. The strength of the adsorbent in each consecutive bed increases until the last bed, which consists of the strongest adsorbent. In this way, the strongest adsorbents will not be exposed to the least volatile analytes from which would be difficult to desorb. For desorption, the flow is reversed, the preconcentrator is resistively heated, and the trapped analytes are desorbed as a narrow plug. Design features and performance data for both the online pyrolysis device and the online preconcentrator will be presented. Comparisons will be made with more conventional pyrolysis techniques.
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