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SIMPLIFIED METHOD FOR EXTRACTING BOUND PESTICIDES FROM AVIAN SERUM
Citation:
Ellington, J J., J J. Evans, AND S. E. Sundberg. SIMPLIFIED METHOD FOR EXTRACTING BOUND PESTICIDES FROM AVIAN SERUM. Presented at 24th Annual Society of Environmental Toxicology and Chemistry Meeting, Austin, TX, November 9-13, 2003.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
A simple solid-phase extraction (SPE) method was developed to extract organochlorine pesticides (OCs) and persistent organic pollutants (POPs) from avian serum. In this method, a 1-mL serum sample fortified with two levels of OCs or POPs was treated with 8M urea or 4M urea and 4M guanidine hydrochloride (GH) to denature serum proteins without precipitation. Urea or the urea and the GH-treated serum was applied to a washed 30-mg Oasis HLB cartridge to extract fortified pesticides from the serum sample by gravity flow. The cartridge was rinsed with three 1-mL volumes of deionized water also by gravity flow and dried for ten minutes under gentle vacuum. POPs and OCs were eluted from the cartridge into a 2-mL gas chromatography (GC) sample vial with 1 mL methylene chloride by gravity flow, and residual methylene chloride was removed from the cartridge using gentle vacuum. A small amount of the methylene chloride was not recovered. Therefore, the vial contents were brought to a total volume of 1 mL using a Hamilton 1000 microliter syringe. Lipids were not retained on the cartridge; thus, no additional fat cleanup was necessary. POPs and OCs were separated by GC, quantified by electron capture detection and verified by GC mass spectrometry. Pesticide recoveries ranged from 73-104%. Although the 1-mL sample size was used for method development, avian serum volumes as low as 20 microliter have been analyzed in this laboratory using this method. This method is faster (< 1hr), easier (two solvents), and as efficient if not more efficient than previously developed SPE and liquid-liquid extraction (LLE) methods for separating pesticides from serum.