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EVALUATION OF ANALYTICAL METHODS FOR DETERMINING PESTICIDES IN BABY FOOD
Chuang, J. C., M. A. Pollard, M. Misita, AND J M. Van Emon. EVALUATION OF ANALYTICAL METHODS FOR DETERMINING PESTICIDES IN BABY FOOD. ANALYTICA CHIMICA ACTA 399(1-2):135-142, (1999).
The overall objectives of the task include several components: (1) develop immunochemical methods for compounds difficult to analyze by conventional methodologies; (2) tailor immunochemical methods to support specific human exposure assessment studies; (3) team immunochemical sample preparations with instrumental analysis such as mass spectrometry for in-depth sample characterization; (4) provide methods to support NERL's human exposure and environmental monitoring efforts; (5) provide analytical methods that improve risk assessments by reducing the amount of uncertainity in environmental measurements; (6) provide multimedia analytical methods to support an integrated multimedia approach to assess and characterize risk to human health and the environment; (7) provide sponsorship of annual immunochemistry research meetings as a forum for stimulating interest and discussion on current or emerging bioanalytical methods; (8) develop and incorporate rapid, cost-effective laboratory and field portable immunochemical techniques such as enzyme-linked immunosorbent assay (ELISA) methods into monitoring studies and human exposure field surveys to delineate sub-populations of "highly exposed" individuals for detailed follow-up studies.
Specific method needs have been identified through consultations with client office personnel. This Task strives to fulfill those needs as appropriate. In particular, methods for pyrethroids, e.g., permethrin, cypermethrin, and deltamethrin are being developed and evaluated. Efficient sample preparations are under development for exposure samples using pressurized liquid extraction. Confirmation will be achieved using high performance liquid chromatography (HPLC). A rapid immunoassay approach for the analysis of 2,4-D in urine will be completed and a SOP and report written. Immunoaffinity chromatography sample preparations for the pyrethroids will be developed. Work will continue on the application of antibody replacements such as molecularly imprinted polymers. Additional candidate analytes will be identified for a tiered approach and to guide development of the next Task. Flexibility will be maintained to address methods and measurement issues as they arise during the task period which ends in FY06. The objective of the Task is to develop bioanalytical methods to support exposure monitoring studies during the task period.
Three extraction methods and two detection techniques for determining pesticides in baby food were evaluated. The extraction techniques examined were supercritical fluid extraction (SFE), enhanced solvent extraction (ESE), and solid phase extraction (SPE). The detection techniques used were enzyme-linked immunosorbent assay (ELISA) and gas chromatography/mass spectrometry (GC/MS). Different SFE and ESE conditions were considered, and the resulting extracts were analyzed by either ELISA or GC/MS. The use of C18 SPE cartridges to extract pesticides from baby food were also evaluated.
Using SFE-ELISA, recoveries of most spiked pesticides were less than 50% in both non-fat and fatty baby food. Using SFE-GC/MS, recoveries of target pesticides were greater than 80% in dried baby food, but 10-60% of the spiked pesticides were lost during the freeze-drying process. Off-line coupling of SPE-GC/MS provided a quantitative measure (>80%) of the pesticides in non-fat baby food (fruits and vegetables). Direct ELISA applied to diluted non-fat food also gave a quantitative measure of the target pesticides. The ESE-ELISA method provided a quantitative determination of atrazine in both non-fat and fatty baby food.
This work was supported by US EPA Contract No. 68-D4-0023 to Battelle Memorial Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
HUMAN EXPOSURE AND ATMOSPHERIC SCIENCES DIVISION
HUMAN EXPSOURE RESEARCH BRANCH