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Cited by 37Forensic Toxicology and Drug AnalysisAnalytical chemistry methods developmentAnalytical Methods in Pharmaceuticals

High-throughput quantification of emerging “nitazene” benzimidazole opioid analogs by microextraction and UHPLC–MS-MS

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Schüller, Maria, Lucic, Ivana, Øiestad, Åse Marit Leere, Pedersen-Bjergaard, Stig, Øiestad, Elisabeth Leere·2023·Journal of Analytical Toxicology
DOI 10.1093/jat/bkad071PMC PMC10714918
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Abstract

Benzimidazole opioids, often referred to as nitazenes, represent a subgroup of new psychoactive substances with a recent increase in fatal overdoses in the USA and Europe. With a variety of analogs emerging on the illicit drug market, forensic laboratories are challenged to identify these potent drugs. We here present a simple quantitative approach for the determination of nine nitazene analogs, namely, clonitazene, etodesnitazene, etonitazene, etonitazepyne, flunitazene, isotonitazene, metodesnitazene, metonitazene and protonitazene in whole blood using liquid-phase microextraction and electromembrane extraction in a 96-well format and liquid chromatography–tandem mass spectrometry. Green and efficient sample preparation was accomplished by liquid-phase microextraction in a 96-well format and resulted in high extraction yields for all analytes (>81%). Here, blood diluted with buffer (1:1, %v) was extracted from a donor compartment across a thin organic liquid membrane and into an aqueous acceptor solution. The acceptor solution was collected and directly injected into the analysis platform. Chromatographic separation was accomplished with a biphenyl column, allowing for a baseline separation of the structural isomers isotonitazene and protonitazene before detection by multiple reaction monitoring. Validation was performed according to Scientific Working Group of Forensic Toxicology guidelines. The calibration range was from 0.5 to 50 nM (except for protonitazene and clonitazene from 0.1 nM) with good linearity and limits of detection down to 0.01 nM. An AGREEprep assessment was performed to evaluate sample preparation greenness, with a final score of 0.71. Nitazenes represent a current threat to public health, and analytical methods that cover a wide range of these analogs are limited. Here, the described method may assist in the detection of nitazenes in whole blood and prevent these substances from being missed in postmortem investigations.

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  • Liquid chromatography-mass spectrometry-based techniques, such as liquid chromatography-triple-quadrupole mass spectrometry and liquid chromatography-time-of-flight mass spectrometry, have become the preferred approaches for screening and quantification in forensic and toxicological laboratories.

    “Liquid chromatography–mass spectrometry-based techniques, such as liquid chromatography–triple-quadrupole mass spectrometry and liquid chromatography–time-of-flight mass spectrometry, have become the preferred approaches for screening and quantification in forensic and toxicological laboratories.”

    From Nitazenes: The Emergence of a Potent Synthetic Opioid Threat (2025) · cites this paper as [56]

    Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

    Experimental — accuracy not yet measured

  • These advanced LC-MS systems can achieve the low limits of detection and quantification required for nitazenes.

    “These advanced systems can achieve the low limits of detection and quantification required.”

    From Nitazenes: The Emergence of a Potent Synthetic Opioid Threat (2025) · cites this paper as [56]

  • High-resolution mass spectrometry is particularly valuable for non-targeted screening and structural elucidation of new nitazene analogues.

    “High-resolution mass spectrometry is particularly valuable for non-targeted screening and structural elucidation of new analogues [52,53,54,55,56].”

    From Nitazenes: The Emergence of a Potent Synthetic Opioid Threat (2025) · cites this paper as [56]

    The Experimental procedures (UHPLC–MS-MS; page unavailable) describe targeted multiple-reaction monitoring on a triple-quadrupole instrument. The Conclusion (page unavailable) concerns quantification of nine specified nitazenes. Searches for high-resolution mass spectrometry, non-targeted screening, and structural elucidation found no passage assessing the claimed value of high-resolution mass spectrometry. (LLM, conf=0.74)

    Experimental — accuracy not yet measured

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Cited by

Sorted by citations

Authors
Schüller, M., Lucic, I., Øiestad, Å. M. L., Pedersen-Bjergaard, S., & Øiestad, E. L.
Affiliations
  • University of Oslo (NO)
  • Oslo University Hospital (NO)
  • Department of Pharmacy, University of Oslo , P.O. Box 1068 Blindern, Oslo 0316, Norway
Corresponding author
Øiestad, Elisabeth Leere
ORCID
Venue
Journal of Analytical Toxicology
Publisher
Oxford University Press (OUP)
Published
2023-09-13
Volume
47
Issue
9
Pages
787-796
ISSN
  • 0146-4760 (ISSN-L)
  • 1945-2403
DOI
10.1093/jat/bkad071
PMC
PMC10714918
OpenAlex
W4386694521
Cited by
37
References
4
Citations by year
2026: 11 · 2025: 16 · 2024: 10
FWCI
6.56
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Analytical Toxicology (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • Research at the University of Copenhagen (University of Copenhagen) (publishedVersion, cc-by)
  • NORA - Norwegian Open Research Archives (submittedVersion, cc-by-nc)
Topics
  • Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Toxicology › Forensic Toxicology and Drug Analysis
  • Physical Sciences › Chemistry › Analytical Chemistry › Analytical chemistry methods development
  • Physical Sciences › Chemistry › Analytical Chemistry › Analytical Methods in Pharmaceuticals
Keywords
nitazenes, new psychoactive substances, liquid-phase microextraction, electromembrane extraction, whole blood analysis, forensic toxicology, etonitazene, isotonitazene, structural isomers, postmortem drug detection, green sample preparation, AGREEprep
MeSH terms
Analgesics, Opioid, Benzimidazoles, Chromatography, High Pressure Liquid, Illicit Drugs, Tandem Mass Spectrometry

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