Differentiation of oleoresin capsicum sprays based on their capsaicinoid profiles

Rafał Borusiewicz; Agnieszka Martyna; Grzegorz Zadora; Anastasiia Zahrebelna

doi:10.1016/j.forsciint.2021.111031

Differentiation of oleoresin capsicum sprays based on their capsaicinoid profiles

Forensic Sci Int. 2021 Nov:328:111031. doi: 10.1016/j.forsciint.2021.111031. Epub 2021 Sep 23.

Authors

Rafał Borusiewicz¹, Agnieszka Martyna², Grzegorz Zadora³, Anastasiia Zahrebelna⁴

Affiliations

¹ Institute of Forensic Research, Westerplatte 9, 31-033 Krakow, Poland. Electronic address: rborusiewicz@ies.gov.pl.
² Forensic Chemistry Research Group, Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, Bankowa 12, 40-007, Katowice, Poland. Electronic address: agnieszka.martyna@us.edu.pl.
³ Institute of Forensic Research, Westerplatte 9, 31-033 Krakow, Poland; Forensic Chemistry Research Group, Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, Bankowa 12, 40-007, Katowice, Poland.
⁴ Forensic Chemistry Research Group, Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, Bankowa 12, 40-007, Katowice, Poland.

PMID: 34600267
DOI: 10.1016/j.forsciint.2021.111031

Abstract

Oleoresin capsicum (OC) sprays, often referred to as 'pepper sprays', contain a solution of active compounds, exerting an irritating effect on the human body. The active component of OC sprays are capsaicinoids, obtained by extraction from peppers. The profiles (quantitative relations) of natural capsaicinoids depend on the plant material, they were extracted from. Pepper spray is a non-lethal weapon that should only be used for self-defense but is often used by criminals to attack and incapacitate victims. Evidence related to these types of incidents, such as containers, clothes of victims or suspects, as well as traces of substances found at the scene, are submitted to the forensic laboratory. The purpose of the analysis is to identify the ingredients of the preparation (especially active components) and compare the traces found on objects from the victim or the scene of the incident with the preparation from the can or traces found on objects related to the suspect. The study aimed to investigate the possibility of differentiating OC gases based on capsaicinoid profiles recorded in GC-MS analyses. Sixty-four gases from 12 different manufacturers were purchased and tested. The likelihood ratio (LR) approach was applied to the data expressing the relative capsaicinoids contents computed by integrating GC-MS signals. Two hypotheses were assumed that stated either common or different origins of the samples. Several LR models have been developed, and their performance has been controlled by the number of false positives and false negatives as well as empirical cross entropy. The research results showed that differentiation was very successful, with more than 90% of correct responses. The results obtained show that OC sprays may be distinguished, even if they were produced by the same producer presumably if produced using different batches of pepper extract.

Keywords: Capsaicinoids; Comparison; Gas chromatography–mass spectrometry; Likelihood ratio; Pepper sprays.

MeSH terms

Capsicum*
Gas Chromatography-Mass Spectrometry
Gases
Humans
Plant Extracts

Substances

Gases
Plant Extracts
oleoresins