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Title: PRESSURIZED HOT (SUBCRITICAL) WATER EXTRACTION COMBINED WITH SOLID-PHASE MICROEXTRACTION FOR DETERMINING ATRAZINE IN BEEF KIDNEY

Author
item Curren, Meredith
item King, Jerry

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: In order to provide safe food for consumers, we need to ensure there are little or no contaminants remaining in the food from the application of chemicals used to kill harmful insects. We also want to use environmentally friendly methods to analyze for these chemicals so that both the environment and the laboratory workers are protected. We have developed a test for the commonly used farm chemical called atrazine using water and alcohol at high temperatures. Even minute traces of atrazine can be detected using these environmentally friendly liquids. The use of this method by food-testing laboratories will ensure that the food that we eat will continue to be the safest in the world. In addition, both the environment and laboratory workers will benefit from this new method.

Technical Abstract: The determination of the levels of pesticides in food products has prompted the development of sensitive and rapid methods of analysis that are solvent-free or utilize solvents that are benign to the environment and laboratory worker. In this study, we have developed a novel extraction method that utilizes ethanol-modified subcritical water in combination with solid-phase microextraction (SPME) for the removal of atrazine from beef kidney. In situ sample clean up was achieved using the technique of matrix solid-phase dispersion. A cross-linked polymer, XAD-7, was utilized as a dispersing material for kidney samples. Subcritical water extractions were performed with a pressurized solvent extraction unit at 100 C and 50 atm. Experimental parameters investigated were the volume of solvent and amount of modifier required for the complete extraction of atrazine, and optimization of the extraction time. It was determined that 30% ethanol in water (v/v) is adequate for the extraction of atrazine. A Carbowax-divinylbenzene SPME fiber was used to sample the aqueous extracts. Analysis of the fiber contents was by ion trap GC/MS utilizing the single ion mode. The total time of analysis for a single kidney sample is 90 minutes. The method limit of detection for beef kidney spiked with atrazine was found to be 0.02 ng/g of sample.