Simultaneous Qualitative and Quantitative Analyses, I. Precision Study of Compounds Amenable to the Inert Gas-Purge-and-Trap Method

The single laboratory total method precision was determined for the analysis of volatile organic compounds in water. A group of twenty-seven compounds was studied which included C1-C3 halogenated materials and substituted benzenes in the 20–30μg/liter concentration range. The compounds were extracted with an inert gas purge, trapped on a porous polymer adsorbent, thermally desorbed, separated by packed column chromatography, and measured by mass spectrometry using the repetitive measurement of spectra method of data acquisition. The relative standard deviations for repetitive analyses were in the 2–13% range and depended on the compound subgroup and whether the internal or external standard method of calibration was used. Factors affecting the precision of the analysis are discussed.