Determination of methomyl in the stomach contents of baited wildlife by gas chromatography–mass spectrometry

Abstract

The poisoning of wildlife with fly-bait containing the active ingredient methomyl is an intentional and illegal act in many jurisdictions. A case of 2 animals poisoned by methomyl through consumption of tainted bait at multiple stations is described. Although thermally and ultraviolet-labile, methomyl can be identified by gas chromatography–mass spectrometry and is detected in abundance in bait samples; however, it is not readily observed in tissues, owing to its rapid metabolism and elimination. The application of derivatizing functionalities, such as trimethylsilyl groups, stabilizes the methomyl-oxime metabolite to facilitate its detectability during exposure to the relatively harsh conditions of gas chromatography. This brief communication reports on the analytical detection of methomyl in baits and biological samples from poisoned wildlife. Essential to the case were the added determination of a fly-bait coactive ingredient, ( Z)-9-tricosene, and identification of a chemical indicator, caffeine, to confirm both the type of pesticide product involved in the poisoning incident and the vehicle used to perpetrate its delivery.

Rapid identification of pesticides in human oral fluid for emergency management by thermal desorption electrospray ionization/mass spectrometry

“…Traditionally, the pesticides present in blood are characterized by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) . Although both techniques are sensitive and reliable, laborious and time‐consuming sample pretreatment processes such as solvent extraction, filtration, concentration, fractionation and derivatization are needed to avoid the interferences from predominant biological compounds in the biological fluids . Pesticides are usually identified within hours by means of these conventional methods.…”

Thermal desorption ambient ionization mass spectrometry for emergency toxicology

“…Unfortunately, it is extremely hard to identify ingested pesticides at the early stage of emergency care, as labeled containers of the offending agents are not always available and toxidromes are at times confusing, if not misleading (Aardema et al, 2008). Despite the fact that most pesticides exist in blood samples are sensitively and accurately detected by GC‐MS‐MS or LC‐MS‐MS in current practice (Cazorla‐Reyes et al, 2011; Dulaurent et al, 2010; Frías et al, 2004), technical‐demanding and time‐consuming sample pretreatment, such as solvent extraction, filtration, concentration, fractionation, and derivatization, are mandatory to eschew matrix effect due to other predominant biological compounds in the specimen (Buchweitz et al, 2013; Dujaković et al, 2010; Rotenberg et al, 1995). As a consequence, it takes hours for these traditional means to identify the pesticides and such turnaround time is too long to be useful for guiding critical care in the emergency department.…”