QUALITATIVE-ANALYSIS OF CONTAMINATED ENVIRONMENTAL EXTRACTS BY MULTIDIMENSIONAL GAS-CHROMATOGRAPHY WITH INFRARED AND MASS-SPECTRAL DETECTION (MDGC-IR-MS)

The use of capillary gas chromatography in conjunction with spectral d etection has been utilized for several years for both quantitative and qualitative analyses of environmental extracts. Unfortunately, in som e extreme cases, chromatographic peak overlap precludes the accurate i dentification of many of the components, and alternative separation st rategies employing multidimensional techniques must be utilized to imp rove the qualitative information. This study presents the application of a valve-based, multiple parallel trap, multi-stage multidimensional gas chromatography-infrared spectroscopy-mass spectrometry system to qualitative analysis of extracts from water, clay and soil samples con taminated by decades of old agricultural product dumping. The water an d clay extracts were found to be fairly simple and required only a sin gle chromatographic stage for analysis. Water and clay contaminants id entified by both infrared (IR) and mass spectra included 1-chloro-4-me thylsulfonyl-benzene, disulfoton, dieldrin, and several organophosphor us pesticides. In contrast, the soil extract required 25 heartcuts and second-stage separations to obtain higher accuracy qualitative identi fications or classifications. Components identified by IR and mass spe ctra included 1-chlorooctane, dimethyl phthalate, phorate, 4,4'-dichlo robenzophenone, 3,4'-DDD, chlorobenzilate, 4,4'-DDD, and bis(2-ethylhe xyl)phthalate. This study demonstrates the system's ability to perform equally well in both 1-D and 2-D configurations with these types of s amples, and it also illustrates some of the temperature-dependent limi tations of the system.