TITLE Preparation of the Components of the Modified Method 5 (Method 0010) Sampling Train for Analysis by SW-846 Method 8270 AUTHOR(S) James F. McGaughey, Raymond G. Merrill, Jr., Joan T. Bursey, and Denny E. Wagoner, Radian Corporation, Merrill D. Jackson and Larry D. Johnson, EPA PERFORMING ORGANIZATION NAME AND ADDRESS Radian Corporation P.O. Box 13000 Research Triangle Park, North Carolina 27709 SPONSORING AGENCY NAME AND ADDRESS U.S. Environmental Protection Agency SMRB, MRDD, AREAL, ORD Research Triangle Park, North Carolina 27711 ABSTRACT To validate a source test method for EPA use, data on the method's accuracy and precision must be obtained at, at least, two different locations. While evaluating a new method for measuring source emissions of semivolatile halogenated compounds, data at one source were significantly different from previous laboratory and field measurements. Recoveries at this source, a chemical manufacturing facility with substantial moisture in the exhaust stream, were unacceptably low, ranging from 4 to 63 percent. Because these results were at variance with previous results, the sampling and analysis procedures were evaluated in detail. The quality control samples isolated the problem to the analysis procedures associated with transfer and extraction of the XAD-2 adsorbent, which was wet when it returned from the field test at this site. Sample preparation procedures had generally followed those specified by the Semi-Volatile Organic Sampling Train method (Semi-VOST; SW-846 Method 0010), but additional procedures, not specifically prohibited by the standard method, were utilized to extract the wet XAD-2 from the sample train before extraction and analysis. These techniques changed the nature of the resulting extract and suppressed recovery of the target compounds. A new protocol has been developed to address sample handling for XAD-2 under such conditions.