In postmortem toxicology, certain cases require the examination of embalmed biological specimens to investigate the presence and potential role drugs may have played in a person’s death. Key factors, like postmortem distribution, which can be greatly affected by temperature, may alter drug concentrations in different areas of the body. In the United States, the involvement of cocaine in overdose deaths has significantly increased between 2012 and 2019 (1). The purpose of this project was to examine the stability of cocaine and its primary metabolite, benzoylecgonine, in perfused postmortem rat tissues stored at different temperatures over a one month. Twelve frozen cocaine positive rat specimens, intracardially perfused with a saline and formaldehyde solution, were received from a chronic cocaine rat study at Boston University Department of Psychological and Brain Sciences (Dr. Kathleen Kantak, Boston, MA, USA). The specimens were dissected, and the spleen, one kidney, and one lung were removed from each specimen. A fine-needle aspiration biopsy was performed on each organ to collect a time zero (T0) sample. One set of four rat specimens were stored at room temperature (20-22°C), another four were stored at refrigerator temperature (4°C), and another four were stored at freezer temperature (-20°C). A section of each organ was collected for analysis at two weeks (T1) and one month (T2). Samples underwent solid-phase extraction before liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis using a QSight 220 CR Laminar Flow Triple Quadrupole Mass Spectrometer with electrospray ionization, operated in positive ion mode (PerkinElmer, Shelton, CT, USA). Simplicity 3QTM software (PerkinElmer) was used for all data collection, analysis, and quantification. All calibration curves generated for each analyte had acceptable R2 values greater than 0.98 using a weighted linear regression model (1/x). Between T1 and T2, eight samples demonstrated a 15-873% increase in cocaine concentration and four samples had a 13-45% decrease in cocaine concentration. For benzoylecgonine, nine samples demonstrated an 18-289% increase in concentration between T1 and T2 and six samples had a 3-57% decrease in concentration. In samples collected at one month, concentration values for cocaine were highest in samples stored at freezer temperature (-20°C) and lowest in samples stored at refrigerator temperature (4°C). The highest benzoylecgonine values were found in samples stored at freezer temperature (-20°C) as well, and the lowest concentrations were in samples stored at room temperature (20-22°C). Due to the variability in analyte concentration in the organs of the intracardially perfused specimens, the impact storage conditions had on analyte stability could not be determined.

Reports of declining insect populations suggest that more research focusing on this phenomenon is needed, especially in pollinator insects. Climate change, habitat destruction, and usage of certain pesticides have all been implicated in insect decline. Neonicotinoid pesticides are highly toxic to bees, can have drastic sub-lethal effects on behavior, and are persistent in the environment; likewise, they have been implicated as a major factor affecting bee populations. However, there are limited studies on native bees regarding their interactions with neonicotinoids, even regarding simple questions such as exposure levels. In this study, we aimed to assess concentrations of common neonicotinoids in native bees and soils from a threatened habitat in our region, the Black Belt Prairie, by using a modified QuEChERS LC/MS-MS protocol. Our results showed that specific taxa of native bees- Bombus spp., Xylocopa spp., and Mellissodes spp. (Family: Apidae)- were exposed to neonicotinoids. In contrast, no concentration of neonicotinoids was detected in our soil samples.

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