1. Total Diet and Pesticide Research Center, U. S. Food and Drug Administration, Lenexa, KS 66214
2. Chemistry Department, Park University, Parkville, MO 64152
3. Biochemistry Department, University of Missouri, Columbia, MO 65212
4. Department of Chemistry and Biochemistry, University of Missouri–St. Louis, MO 63121
5. Chemistry Department, Park University, and Total Diet and Pesticide Research Center, U. S. Food and Drug Administration, Lenexa, KS 66214