QUANTITATION REFERENCE COMPOUNDS AND VOC RECOVERIES FROM SOILS BY PURGE-AND-TRAP GC MS/

Unquantified volatile organic compound (VOC) losses occur in every pha se of VOC determination including sample collection, transport, storag e, preparation, and analysis. Current quality assurance/quality contro l measures, such as surrogate spikes and internal standards, do not ac count for losses that occur during sample handling nor do they account for soil matrix effects. An alternate approach, the quantitation refe rence compound (QRC) approach, is presented that involves direction in jection of the QRCs onto the soil matrix to account for any matrix eff ects and losses during subsequent processing steps prior to sample ana lysis. Final VOC quantitation is based on the QRC instead of the inter nal standard, which is used strictly to monitor instrument performance . Quantifying VOCs using the QRC approach on three spiked performance evaluation soils and one unprocessed spiked field soil resulted in tar get compound relative recoveries of 93-105%. In contrast, using the cu rrent quantitation approach, target compound recoveries were only 2-27 %. Precision between the two approaches was equivalent (on an absolute basis) with relative standard deviations of 2-15% using the QRC appro ach.