Rapid sample preparation methods for use with high-speed gas chromatography

Rapid sample preparation schemes for analysis of high humidity gas and aqueous samples by high speed gas chromatography (HSGC) are described in this dissertation. Sample preparation methods are known to be a limiting factor in HSGC analysis. Most notably, cryointegrating HSGC instruments have been limited to the analysis of dry gas samples. This dissertation addresses known limitations, and provides methods for expanding the use of cryointegrating HSGC to high humidity gas samples, as well as samples in an aqueous matrix.; Cryointegrating HSGC was used to monitor the efficiency and changes in activity of a biofiltration apparatus. This was done by designing a system to sample inlet and outlet concentrations of analytes from a gas stream undergoing biofiltration. By alternating sample collection between the inlet and outlet, and by using a Nafion dryer to remove humidity, this system was capable of collecting two concentration measurements every minute. This system was further demonstrated to be capable of monitoring rapid; fluctuations in concentration in a gas and changes in biofilter activity during watering cycles.; A rapid aqueous sample preparation (RASP) system has been constructed and characterized for the analysis of volatile organic compounds (VOCs) with a cryofocusing HSGC instrument. The RASP system quantitatively extracts VOCs from an aqueous matrix in approximately 20 seconds, a time that is compatible with HSGC analysis. The RASP system allows successive injections, as demonstrated by an example of sequential extraction and separation of four aqueous samples in less than 3 1/2 minutes. Analysis time was minimized by optimizing the RASP system and designing an interface to allow concurrent extraction and separation. The entire sample extract is introduced to the cryofocusing injector of the HSGC, resulting in excellent sensitivity. Injection of only 100 microliters of an aqueous mixture of VOCs in the low parts per billion range resulted in chromatographic peaks with signal-to-noise ratios ranging from 6.5 to 41 depending on analyte. Reproducibility of sequential analyses at this concentration resulted in less than 5% relative standard deviation.