TITLE Field Test of a Generic Method for Halogenated Hydrocarbons AUTHOR(S) Joan T. Bursey, Raymond G. Merrill, Jr., Robert A. McAllister, and James F. McGaughey PERFORMING ORGANIZATION NAME AND ADDRESS Radian Corporation P.O. Box 13000 Research Triangle Park, NC 27709 SPONSORING AGENCY NAME AND ADDRESS Atmospheric Research and Exposure Assessment Laboratory United States Environmental Protection Agency Research Triangle Park, North Carolina 27711 ABSTRACT Validation of a method for a particular analyte or group of analytes means that the performance of the sampling and analytical methodology for these analytes has been established and demonstrated through field tests at the type of source category of interest: that is, the precision and bias of the method have been established experimentally. In examination of the available method validation data for organic compounds listed in Title III of the Clean Air Act Amendments of 1990, the lack of overall method validation data is readily apparent. In some cases, analytical methods have been validated for a number of analytes, but there is no validation information for the sampling methodology. Full validation for both sampling and analytical methods, for both field and laboratory operations, is available for fewer than 10 percent of the analytes listed in Title III of the Clean Air Act Amendments at any source category. Field validation may be performed by side- by-side comparison of a candidate method to a validated method to establish comparable performance for the same analytes in the same matrix (same source category). Another procedure for validation of a method is to perform spiking operations in the field so that the precision and bias of the method can be demonstrated from sample collection through analysis.