| Scope and Method of Study: The purpose of this research was to develop and validate a method for the detection of low levels of HMTD extracted from building materials using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Method validation was performed to determine precision, accuracy, sensitivity, and selectivity. For each building material an extraction method was developed, and the percent of HMTD recovered through extraction was determined. Carpet, wood, concrete, and drywall samples were spiked with a known amount of HMTD analytical standard and the HMTD was then periodically extracted from each of the different materials and analyzed using LC/MS/MS. The amount of HMTD recovered from the building materials was then assessed to determine the degradation and recovery time of HMTD and establish which materials would most likely have detectable residues of the explosive in the event of an investigation.;Findings and Conclusions: The LC/MS/MS method was successfully developed to detect low amounts of HMTD that was extracted from carpet, wood, concrete, and drywall. The method utilized isocratic flow rate with electrospray ionization and three ions representative of HMTD in multiple reaction monitoring (MRM) mode. The limit of detection for carpet was 0.18 microg, wood was 0.60 microg, concrete was 0.19 microg, and drywall was 0.14 microg. Carpet extractions had the highest percent of HMTD recovered (81%), while drywall (32%), wood (18%), and concrete (8%) extractions showed much lower recovery. This study indicates that in an area where HMTD may have been produced the best samples to be collected for the identification of HMTD are those of carpet, as carpet will yield the highest amount of HMTD for the longest amount of time when compared to wood, concrete, and drywall. If carpet is unavailable for collection, other building materials should be collected. After carpet samples, drywall has the highest amount of HMTD recovered; however, wood samples yield detectable HMTD for a longer period of time. Concrete samples yield the lowest amount of HMTD throughout the study and showed a slightly shorter timeframe for detection when compared to drywall, making it the least likely of the materials to contain HMTD residues in an investigation. |
