Old Poison, New Problem: Cyanide Fatal Intoxications Associated with Internet Shopping

Widespread access to the Internet has an increasing influence on how suicides are committed. On websites such as eBay® or Amazon.com® highly toxic substances including cyanides are available for purchase. In the last 5 years, a few fatal intoxications associated with Internet shopping and buying "suicide kits" have been reported. Epidemiology of intoxications reported by American Association of Poison Control Centers between 2000-2018 shows that about 10% of all exposures to cyanide were related to suicide attempts and intentional ingestion of this substance. In order to determine the cyanide concentration in four fatal intoxication cases associated with Internet shopping, a headspace gas chromatography with dual column/dual flame ionization detector (HS-GC-FID/FID) method was validated and applied to casework. The method was linear in range, from 1 to 50 µg/mL, with a coefficient of determination of 0.999 (R2). The limit of quantification was 1.0 µg/mL; the detection limit was 0.5 µg/mL. Intra- and inter-day validation precision and accuracy did not exceed 10% and 15%, respectively. Recovery and matrix effect values ranged from 94.8- 103.8% and -5.2─3.8%, respectively. The cyanide concentrations were determined in biological fluids (blood, urine, bile, vitreous humor, gastric content) and postmortem tissue samples (spleen, kidney, liver, brain). The headspace gas chromatographic method, which is routinely used in clinical and forensic toxicology to quantify ethanol with its congeners (methanol, acetone, isopropanol, n-propanol and n-butanol), can be also applied to determine cyanide in intoxication cases. The global problem of a high number of suicides each year, requires increasing and more restrictive control of highly toxic substances available online as well as caution monitoring of human exposure to cyanide. This old and well known poison is being increasingly used nowadays for suicidal purposes, therefore determination of cyanide in biological samples is still important in terms of clinical and forensic toxicology.