Conclusions
GCxGC is a powerful way to reduce the possibility of quantification bias when using a non-specific
detector such as an ECD. As shown in this application note, it may be better than parallel dual-
column analysis (while still providing a dual-column approach), for the organochlorine pesticides of
EPAMethod 8081, especially when the samples contain PCBs.
Calibrations (ECD responses) are linear, even across relatively wide concentration ranges. Due to
the focusing effect of GCxGC, where peaks are sharpened close to the detector, sensitivity is
improved, which allows detection of low femtogram levels of many OCPs.
Split injections of dirty samples, possible due to the elevated sensitivity affordedwhen using
GCxGC-ECD, may lead to less downtime due to injector and columnmaintenance.
Acknowledgment
Jennifer Clements and Bryce Stearns at STL Burlington kindly provided the sample extracts, the
GC-ECD results, and also helpedwith data interpretation.
References
United States Environmental Protection Agency, Test Methods: SW-846 on-line;
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