United States environmental protection agency perchlorate method 332.0. Statistically sound recovery studies in...

This research is a continuation of an earlier work, which evaluated the United States Environmental Protection Agency's Perchlorate Method 332.0, in which standards were prepared in deionized water over an extended concentration range (i.e., to a maximum of 200 μg/L). This current paper investigates the performance of the same method in which standards were made in simulated drinking water. A microbore format with a 15-μL injection volume was employed to conduct a recovery study and generate recovery curves (which hold the key to a statistically sound assessment of method performance in more complex matrices). The maximum analyte concentration range was 1 to 200 μg/L. For various subset concentration ranges, recovery evaluations were made using both raw peak-area data and analyte responses scaled by the internal standard (ISTD). The results indicate that in complicated matrices such as drinking water, ISTDs may not provide simultaneously high precision and recovery.