Rapid, Presumptive Identification of Seed-Based Toxins using Direct Analysis in Real Time Mass Spectrometry (DART-MS) and its Variants

Detection of seed-based toxins is a need for forensic chemists when suspected poisonings occur. The evidence that is found is often physically unidentifiable, as the seeds are mashed to extract the toxins. This work investigates potential strategies for rapid detection of seed-based toxins using chemical signatures obtained by direct analysis in real time mass spectrometry (DART-MS). Seven toxins (digoxin, digitoxin, hypaconitine, hyoscyamine, lanatoside, oleandrin, and scopolamine) and six seeds containing these toxins were studied. While detection of four of the toxins was readily attainable, detection of digoxin, digitoxin, and lanatoside was hindered by the inability to thermally desorb these larger compounds under normal operating conditions. The use of DART-MS variants capable of higher temperature analysis (thermal desorption (TD)-DART-MS and infrared thermal desorption ((IRTD)-DART-MS) enabled detection of these compounds. The low-level toxin concentrations and limited number of seeds available for analysis led to detection difficulties from both seed mashes and methanolic seed mash extracts. Principal component analysis (PCA) of generated mass spectra enabled differentiation of seed species, even in the cases when the toxins were undetectable.