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USE OF A MOLECULARLY IMPRINTED POLYMER IN THE DETERMINATION OF PYRETHROID PESTICIDES IN COMPOSITE FOODS
MORGAN, J. N., T. E. HIEBER, A. M. PAWLECKI-VONDERHEIDE, P. KAUFFMAN, L. J. MELNYK, B. BOYD, A. RYBERG, AND E. YLMAZ. USE OF A MOLECULARLY IMPRINTED POLYMER IN THE DETERMINATION OF PYRETHROID PESTICIDES IN COMPOSITE FOODS. Presented at 2007 Florida Pesticide Residue Workshop, St. Pete Beach, FL, July 22 - 25, 2007.
The overall goal of this research program is to identify those chemicals, pathways, and activities that represent the highest potential exposures to children and to determine the factors that influence these exposures. The following objectives will address this goal: (1) Revise and refine the existing research plan for children's exposure measurements research. (2) Collect measurement data on children's exposures. (3) Provide analytical support to children's pesticide exposure research. (4) Develop analytical methods for pesticides in duplicate diet food samples. (5) Develop and apply analytical methods for other chemicals including but not limited to brominated diphenyl ethers, phthalates, perfluorinated chemicals. (6) Evaluate the impact of chiral chemistry on the risk to children and exposure assessment. (7) Provide support to the National Children's Study. (8) Perform data analyses to fill critical data gaps. (9) Conduct analyses of dietary samples and refine the dietary model for the dietary exposure algorithm.
The U.S. Environmental Protection Agency's (EPA) National Exposure Research Laboratory (NERL) measures the exposure of individuals to chemical pollutants through the diet, as well as other media. In support of this research, methods are being evaluated for determination of various classes of pesticides in composite diet samples. Existing methods for pesticides generally have been developed for regulatory purposes and often do not have sufficiently low detection limits for exposure studies. Consequently, there is a need to improve the performance of these methods for analysis of pesticides in composite dietary samples. The objective of this work is to evaluate the applicability of a molecularly imprinted polymer (MIP) based solid phase extraction material for use in the analysis of pyrethroid pesticides in composite dietary samples collected in exposure studies.
A MIP-based solid phase extraction material, specific for pyrethroid pesticides, was developed by MIP Technologies AB, under contract to the EPA. This material was evaluated in combination with a variety of extraction and clean-up techniques in an effort to optimize its performance in the determination of pyrethroid pesticides in composite foods. This presentation will outline the various experiments conducted until acceptable performance was achieved.
The final method consisted of a modified QuEChERS1 procedure followed by a clean-up step using the MIP. Detection was performed using GC/µECD. The procedure was evaluated for cis and trans-permethrin, cypermethrin and cyfluthrin in high, medium and low fat (10%, 5% and 2%, respectively) food samples. Recoveries ranged from 83-126%. Detection limits ranged from 7 to 35 ppb using GC/ECD. This work was designed primarily to evaluate performance of the MIP. Future work will focus on ways to improve detection limits to sub-ppb levels.