Variability and specificity associated with environmental methamphetamine sampling and analysis.
ABSTRACT This study was designed to explore the efficacy of the use of wipe sampling to determine methamphetamine contamination associated with the clandestine manufacture of methamphetamine. Three laboratories were utilized to analyze wipe samples to investigate variability in reported methamphetamine concentration among samples spiked with known amounts of methamphetamine. Different sampling media, surfaces, and solvents were also utilized to determine potential differences in measured methamphetamine concentration due to different wipes, wipe solvents, and wipe contaminants. This study examined rate of false positive detection among blank samples and whether interference with common household substances would create a false positive detection of methamphetamine. Variability between the three labs-using liquid chromatography with mass spectrometry or gas chromatography with mass spectrometry for detection of a known concentration of methamphetamine-resulted in percent differences of 3-30%. Results from wipe sample analysis for methamphetamine, using methanol or isopropanol, showed no significant difference in methamphetamine contamination recovery. Dust and paint contamination on methamphetamine wipe samples with known methamphetamine spike amounts did not affect methamphetamine wipe sample recovery. This study confirmed that either methanol or isopropanol is an appropriate solvent for use in methamphetamine wipe sampling. Dust and paint contamination on wipe samples will not interfere with the wipe sample analysis for methamphetamine. False positive detection for methamphetamine was not observed in any of the blank wipe samples submitted for the study. Finally, this study determined that methamphetamine will not be detected in structures that are truly methamphetamine free at current laboratory limits of quantification.