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Field-portable Gas Chromatograph Mass Spectrometer (GC-MS) Unit for Semi-volatile Compound Analysis in Groundwater

Abstract : This effort demonstrated the use of field-portable instrumentation for the quantification of munitions constituents in groundwater, without the need to ship water samples to a fixed analytical laboratory. The results indicate that similar reporting limits can be obtained using the field-portable instrument when coupled to solid phase extraction sample preparation, yet instrument stability at the low concentration range is an issue. The instrumentation was tested on 28 groundwater samples for a variety of analytes with concentrations ranging up to 3 orders of magnitude. Detection limits for the field instrumentation are generally below regulatory thresholds. Linear regression comparison of the field results to laboratory-based analysis suggest comparability between the techniques, with the slope of the regression for all analytes being between 0.8 and 1.2, except for TNB and RDX. The RDX field results were about 70% of the laboratory results on the average. The field method consistently exhibits a significant positive bias for TNB. The field and laboratory NB results were consistent in that both the field and laboratory methods reported non-detects.