Environ. Sci. Technol. 2007, 41, 5419-5425
Emerging Technologies for Identification of Disinfection Byproducts: GC/FT-ICR MS Characterization of Solvent Artifacts CALEB HEFFNER,† INDIRA SILWAL,† JOHN M. PECKENHAM,‡ AND T O U R A D J S O L O U K I * ,† Department of Chemistry, and Mitchell Center for Environmental & Watershed Research, University of Maine, 5706 Aubert Hall, Orono, Maine 04469-5706
Water samples from a local water treatment plant were analyzed, using gas chromatography Fourier transform ion cyclotron resonance mass spectrometry (GC/FT-ICR MS), to identify potential disinfection byproducts (DBPs). Both liquid-liquid extraction (LLE) and solid-phase microextraction (SPME) techniques were used for sample preparation prior to GC/MS analyses. Based on the averaged mass measurement accuracy (MMA) of better than five parts-per-million ( 30 000 at m/z values ∼110) and MMA of better than one part-per-million (MMA < 1 ppm). The use of thermochemical data, such as proton affinities, as a complementary tool to enhance analytical resolution is also demonstrated.
solvents) (7). Although GC/MS can provide highly accurate and precise data, some LLE methods may cause artifact formation (8-11). The presence of solvent artifacts can adversely affect qualitative and quantitative analyses of unknown water samples. For example, coeluting artifacts can introduce errors when commonly used non-discriminating detectors, such as GC/ECD, are employed to characterize complex sample mixtures. High-performance GC detectors such as FT-ICR MS may be able to differentiate solvent artifacts from other analytes of interest. However, it is desirable to use “clean” techniques and address the formation of artifacts, regardless of the detection methods employed. Since its development (12), SPME has become a popular extraction technique for a wide variety of applications (13). The SPME approach is solventless, potentially cost-effective, sensitive, and portable. Conversely, LLE techniques normally use large amounts of potentially expensive and hazardous organic solvents. In 1993, Chai et al. (14) showed that SPME could be used to sample volatile brominated and chlorinated organic compounds from air and water. Subsequently, Frazey et al. showed that SPME was a viable technique for the analysis of iodinated species in water (15). Previously, we reported on the unique advantages of GC/ FT-ICR MS for analyzing complex sample mixtures (16, 17). GC separated unknowns can be identified confidently by matching their highly accurate (on average
