Determination of Arsenic by Instrumental Neutron Activation Analysis in Sectioned Hair Samples for Forensic Purposes: Chronic or Acute Poisoning?

The study investigated the case of a 29-year-old woman suspected of suicide by arsenic trioxide ingestion, where autopsy findings suggested acute poisoning, but hair analysis indicated chronic exposure. Inductively coupled plasma mass spectrometry (ICP-MS) showed high arsenic levels (26.4 μg g−1) in hair, suggesting chronic poisoning. However, instrumental neutron activation analysis (INAA) of sectioned hair samples revealed arsenic levels between 0.16–0.26 μg g−1, consistent with acute poisoning, as the woman died approximately 14 hours post-ingestion. The discrepancy was attributed to possible contamination of hair or errors in ICP-MS analysis.