MP4 Organic, Metallic, Organometallic Pollutants and Method
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(JON-1117-825731) A unique approach for evaluating Aroclor interference of chlorinated pesticides in tissue.

Jones, L¹, Tritt, M¹, Grindstaff, J², ¹ Integral Consulting Inc., Portland, Oregon, USA² Columbia Analytical Services, Kelso, Washington, USA

ABSTRACT- The analysis of chlorinated pesticides and PCBs in fish tissue can be challenging due to chemical interferences and the need for low detection limits to adequately address potential human health and ecological risks. The first phase of the Portland Harbor remedial investigation included analysis of fish tissue for chlorinated pesticides and PCB Aroclors by gas chromatograph with electron capture detector (GC/ECD), and PCB congeners by high-resolution gas chromatography and mass spectrometry, which are the standard EPA methods of analysis for these parameters for environmental investigations. PCBs are a known interferent in the chlorinated pesticide analysis by GC/ECD (EPA Method 8081A). Evidence of PCB interference was present in the GC/ECD chromatograms for the chlorinated pesticide analysis. A unique approach was developed to separate the PCB interferences from the target chlorinated pesticide parameters. A gas chromatograph and a mass spectrometer equipped with an ion trap (GC/MS ion trap) was used to achieve chlorinated pesticide method detection limits significantly lower than GC/MS method detection limits generated without the ion trap, and resolve the PCB interference. Overall, the GC/ECD and GC/MS ion trap data were comparable for most analytes. The GC/MS ion trap results indicate a positive bias for 2,4′-DDT and 4,4′-DDT from the GC/ECD analysis as a result of interference by specific PCB congeners.′

Key words: pesticides, PCBs, interference, ion trap