Rapid extraction high-speed GC analysis of volatile organic compounds in aqueous samples

摘要

An extraction system to remove volatile organic compounds (VOCs) from an aqueous matrix in a time frame that is compatible with high-speed gas chromatography (HSGC) has been developed and interfaced to a cryofocusing instrument. Using this system, VOCs are quantitatively extracted in similar to 20 s, with no residual signal present during subsequent analysis. This allows successive injections, as demonstrated by sequential extraction and separation of four aqueous samples in less than 31/2 min. Analysis time was minimized by designing the system 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 mu L 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. [References: 22]