Use of isotopes in agrochemical research

摘要

Both radioactive and stable isotopes play a significant role in the research, development and registration of agrochemicals. Tritium labels are frequently used in early compound design and in screening of analogs for biological activity and initial fate data. Radioisotopes can be applied in mechanistic studies to determine distribution of agrochemicals in plants and modes of action. Regulatory agencies, such as the United States Environmental Protection Agency, mandate a series of biotic and abiotic degradation studies that are conducted in a wide variety of biological matrices, including animal, plant, water, soil and aquatic systems. Use of radiolabeled test materials, commonly 14C, allows calculation of balance data and tracking of the degradation products. Data on both degradation kinetics and pathways of degradation are required for registration. Studies require maintenance of a 90-110% radiobalance in biologically viable systems for up to a year, with periodic isolation and structure elucidation of degradation products. Radiolabeled test material allows characterization of degradation products have been incorporated into the biological matrices. This multi year data generation process develops a comprehensive picture of the fate of the agrochemicals. Stable isotopes play significant roles as internal analytical standards in residue analysis and in stewardship monitoring.