The stability of cyanide in human biological samples. A systematic review, meta-analysis and determination of cyanide (GC-QqQ-MS/MS) in an authentic casework 7 years after fatal intoxication

Abstract

A 30 year old man was found with no signs of life in front of the house. The cyanide concentration in blood and urine was determined five years after the man’s death. What is more, a stability study was conducted for 730 days in an authentic casework blood sample. Sample preparation procedure included precipitation with methanol:water mixture, solid phase extraction (SPE) and derivatization with the use of PFB-Br (pentafluorobenzyl bromide). The sample was analyzed using GC-QqQ-MS/MS (gas chromatopraphy coupled with tandem mass spectrometry) isotope dilution method. Separation was done using a SH-RXI-5MS column (30 m x 0.25 mm, 0.25 µm). Detection of PFB-CN and PFB-¹³CN was achieved using a triple-quadrupole mass spectrometer with an electron ionization (EI) ion source in multiple reaction monitoring (MRM) mode. After 5 years from the man’s death, cyanide concentration was: 1900 ng/mL in blood and 500 ng/mL in urine. Stability study performed in an authentic blood sample 6 and 7 years after the man’s death revealed cyanide concentrations of 1898.2 ng/mL and 1618.7 ng/mL, respectively. While spectrophotometric and colorimetric methods recorded both decrease and increase in cyanide concentration over time, newer chromatographic methods mainly indicate a decrease. The studies presented in this paper seem to confirm this trend. However, in order to interpretate the results of cyanide concentration in biological material reliably, more research is still necessary.

Keywords:

• Cyanide stability
• meta-analysis
• GC-EI-MS/MS
• isotope dilution
• pentafluorobenzyl bromide
• phospholipid removal

Author contributions

Writing – original draft preparation, data analysis, meta-analysis performance, visualization; K.T.; methodology, validation, investigation, authentic sample preparation, method development, visualization O.W.; supervision, writing – review and editing, P.S.; writing – review and editing, resources, M.Z. All authors have read and agreed to the published version of the manuscript.

Ethical approval

All procedures performed in this study were in accordance with the ethical standards of the national committee and with the 1964 Declaration of Helsinki. Consent for the study was obtained from the appropriate bioethics committee (consent no. KB-184/2023). Biological fluids (blood and urine) collection from decedent was made by judicial authorities, and the samples were sent to our institute for toxicological analysis at their request. This article does not contain any studies with living human participants or animals performed by any of the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.