Polychlorinated Biphenyls in Contaminated Soil Samples Evaluated by GC-ECD with dual column and GC-HRMS

We present and compare results obtained from the analysis of polychlorinated bipheryls (PCBs) of a limited number of contaminated soil samples collected in three areas of Basilicata region (south of Italy The levels of PCBs were evaluated by using two analytical methods: (i) parallel dual-column gas-chromatography with dual electron capture detectors (GC-ECD) and (ii) gas-chromatography Coupled to high-resolution mass spectrometry (GC-HRMS) via electron impact ionization (EI) in the multiple ion monitoring mode (MIM, two ions per compound). Two extraction methods prior to sample cleanup were also examined: microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE). The MA was the extraction procedure adopted using acetone/n-hexane (1:1. v/v) as it is mainly characterized by higher sample throughput and allowed reduced consumption of organic solvents. While extraction and analysis of spiked soil samples showed the applicability of both methods, systematic difference between the results were obtained for the sum of PCBs as a result of some non-detected congeners be GC-ECD compared with GC-HRMS. Indeed, high resolution MS using El mode (electron energy 40eV with a resolving power of 10,000 provides additional information about the contamination pattern. The GC-ECD screening of 11 soil samples led to just one sample non-compliant to as it was close to the guid value for soils fixed by the Italian legislation (i.e., 60ppb for private or urban soil). Using GC-HRMS. the amount of all PCBs found ranged from 5.4 to 127 ppb with five soil samples non-compliant to the guid Value. The number of identified congeners ranged from 1 to 9 and 9 to 18 using dual-column GC-ECD and GC-HRMS, respectively.