Abstract |
In April 1995, the U.S. Environmental Protection Agency (EPA) sponsored a demonstration of field portable X-ray fluorescence (FPXRF) analyzers. The primary objectives of this demonstration were to evaluate these analyzers for: (1) their analytical performance relative to standard analytical methods, (2) the influence of sample matrix variations (texture, moisture, heterogeneity, and chemical composition) on performance, (3) the logistical and economic resources needed to operate these technologies in the field, and (4) to test and validate an SW-846 draft method for FPXRF analysis. Secondary objectives for this demonstration were to evaluate FPXRF analyzers for their reliability, ruggedness, cost, range of usefulness, data quality, and ease of operation. Both analyzer exhibited precision similar to the reference methods at the 5 to 10 times the precision based method detection limit (MDL) concentration level. As expected, the chromium data generally showed the poorest precision of the primary analytes. Of the four sample preparation steps evaluated, the initial sample homogenization had the greatest impact on data comparability. Site and soil texture did not appear to affect data comparability. Based on the performance of both TN Spectrace analyzers, this demonstration found them to be effective for characterizing the concentration of metals in soil samples. As with all PFXRF analyzers, unless a user has regulatory approval, confirmatory sampling and data correction is recommended when using these analyzers for site characterization and remediation monitoring. |