A crucial aspect of the detection of trace drug residues that is often overlooked is understanding the behavior of these compounds in real-world environments. The ability to predict both the lifetime of drug residues as well as their degradation products under different environments can provide critical information to aid in: determining if collection of a residue is possible, refining alarm algorithms of screening tools, providing guidance on proper storage of samples containing suspected residues, and possibly give insight into potential decontamination protocols.<br/><br/>This work investigated the stability of trace (tens of nanograms) deposits of drugs when exposed to seven environments (-4 °C, 23 °C, 30 °C, 47 °C, 30 °C and 90 % relative humidity, UV exposure, and ozone). Quantitative data was obtained by electrospray ionization mass spectrometry (ESI-MS). The mass loss measurements were then used to establish fitted degradation curves for all drugs and all conditions. Pairwise comparison analysis between different environments for individual drugs was also completed to understand both the similarity between environments and the magnitude different environmental conditions had on mass loss. In addition, full mass spectral data was collected using thermal desorption direct analysis in real time mass spectrometry (TD-DART-MS) in both positive and negative ionization modes to identify and understand spectral abnormalities that could be attributed to degradation or decomposition products formed due to differing environmental exposures.<br/><br/>A total of 8 drugs have been examined from various classes. Mass loss was found to depend on both the environmental condition as well as the compound analyzed. Exposure to UV-light as well as elevated humidity most often had the greatest impact. Major degradation products and pathways for some compounds have also been established. This data may ultimately provide forensic scientists with a better understanding of how trace drug residues will behave under real-world conditions.

Measuring the environmental degradation of traditional drug and new psychoactive substance (NPSs) residues

2019 Spring National Meeting

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