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THE DETERMINATION OF PYRETHROID AND PRETHRIN INSECTICIDES IN FOODS
Citation:
Brisbin, J. AND J N. Morgan. THE DETERMINATION OF PYRETHROID AND PRETHRIN INSECTICIDES IN FOODS. Presented at 2004 Florida Pesticide Residue Workshop, Orlando, FL, July 18-21, 2004.
Impact/Purpose:
The overall objective of the MCEARD dietary exposure research program is to support NERL's human exposure measurement and exposure modeling efforts by reducing the amount of uncertainty in the dietary measurements critically needed for improved risk assessment. Specifically, the research conducted under this task provides the tools needed to analyze composite food and beverage samples for the presence of pesticides, starting with pyrethroids. The specific objectives of this task are to develop and improve analytical methods for contaminants in composite food and beverage samples collected in dietary measurements studies and to analyze small numbers of samples in support of these studies. A series of analytical methods and/or journal articles are anticipated through FY07.
Description:
Pyrethrins, and the more light stable synthetic pyrethroids, are insecticides that are effective against many pests. They have been used for many years and are relatively non-toxic to warm blooded animals. The residue analysis of pyrethrins and pyrethroids is of interest to the U.S. Environmental Protection Agency's (USEPA) National Exposure Research Laboratory (NERL) in relation to multimedia/multi-pathway (aggregate) exposure studies and assessments for the purpose of determining an individual's exposure to various environmental contaminants. In this work an accelerated solvent extraction (ASE) and residue clean-up procedure, previously shown effective in determining a broad range of pesticides in composite diets, were shown effective in extracting pyrethrins and pyrethroids from fortified composite diets. Determinations performed by gas chromatography/electron capture detection (GC/?ECD) showed recoveries ranging from 111% to 130% for the 11 insecticides tested. Determinations by gas chromatography/mass spectrometry (GC/MS) showed recoveries ranging from 94 to 119% for 8 of 13 insecticides tested. Recoveries were higher for allethrin, bifenthrin, cypermethrin and the pyrethrins, but lower for resmethrin. The % relative standard deviation (%RSD) for all of the insecticides was below 15% using GC/ECD and below 10% for all except 3 insecticides using GC/MS. Further determinations of samples fortified at various levels using matrix matched calibration standards are required.