Evaluation of Candidate Procedures for the Preparation of Audit Materials for Analysis of Semivolatile Organic Compounds

Abstract

Audit materials for the SemiVOST method (SW-846 Sampling Method 0010 and Analytical Method 8270) and Standard Operating Procedures for preparation of these audit materials have been developed and are now available from the U.S. Environmental Protection Agency (EPA). The audit materials consist of spiked XAD-2° sorbent. Two procedures were considered: gaseous spiking and liquid spiking. Standard Operating Procedures (SOPs) were prepared based on experience in preparing and analyzing the audit materials. An interlaboratory study involving three laboratories was planned to evaluate the ruggedness and transferability of the standard operating procedures. The initial interlaboratory study was unsuccessful in obtaining a complete data set; however it did demonstrate that a two-week hold time before sorbent extraction did not decrease recoveries of the spiked semivolatile organic compounds. The SOPs were revised after the first interlaboratory study, and a second study involved four laboratories. Three laboratories prepared the audit materials according to the SOPs and all four laboratories analyzed the spiked samples. The complete set of analytical data was statistically evaluated to judge the effectiveness of the SOPs in preparing the audit materials. EPA procedures for preparing audit standards had not been available previously.