What Does EPA Method 625.1 SPE Round Robin Data Really Tell Us?

Oral Presentation

Prepared by P. Newbold
ddms, inc., 186 Center Street, Clinton, New Jersey, 08809, United States


Contact Information: pnewbold@ddmsinc.com; 908-619-9132


ABSTRACT

In 2014/2015, two round-robin studies were held to evaluate the performance of solid phase extraction (SPE) of a full suite of semivolatile analytes in an aqueous matrix. The two rounds were accomplished with approximately six vendors, more than 20 laboratories, and three matrices: reagent water, synthetic wastewater, and TCLP fluid, with the focus on maximizing extraction efficiency for each matrix.
The results were compared to the limits defined in Table 6 of US EPA Method 625.1, and initial data analysis would suggest that the use of SPE yields acceptable recoveries. However, given the wide, and in many cases, low, acceptance criteria, falling within the method-defined limits may not indicate the true performance of the technology.
Despite these disparate recoveries, the data from these studies provide valuable information and insight. How do sorbent types and capacities, matrix effects, and sample volumes affect recoveries generated by Method 625.1?