title: Freeze-thaw stability and long-term stability of 84 synthetic cannabinoids in serum.
abstract: Information about stability of synthetic cannabinoids is important to give recommendations for storage conditions in cases in which use of synthetic cannabinoids is suspected. In this study, freeze-thaw stability (3 cycles at -20 °C at 1.5 ng/mL) and long-term stability at room temperature, 4°C and -20°C (for 150 days) were tested by a validated liquid chromatographic-mass spectrometric method for 80 synthetic cannabinoids. Results demonstrated good freeze-thaw stability for most of the substances. For 5 F-ABICA (72.6% of peak area of time point zero), 5 F- 2 ADB PINACA 2 Isomer (68.7 %), 5Cl-AB-PINACA (84.2 %), AB FUBINACA 2-Isomer (33.5 %), 5 F-PCN (89.7 %), ADB-FUBINACA (78.0 %), EG 018 (88.9 %), and PX-1 (89.4 %) three freeze-thaw cycles led to absolute peak areas < 90% compared to 6 control samples. For 51 of the 84 substances, stability in serum could be demonstrated after 315 days of storage at -20°C. For 82 of the 84 substances, stability in serum could be shown for at least 1 month at -20°C. Long- term stability at 4°C or 20°C showed worse results. Therefore, it is our recommendation to store real serum samples at -20°C until analysis. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Institute of Forensic Medicine, Department of Forensic Toxicology, University of Bonn, Bonn, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Hess
authors.affiliation: Institute of Forensic Medicine, Department of Forensic Toxicology, University of Bonn, Bonn, Germany.
authors.forename: Lynn
authors.initials: L
authors.lastname: Krueger
authors.affiliation: Institute of Forensic Medicine, Department of Forensic Toxicology, University of Bonn, Bonn, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Unger
authors.affiliation: Institute of Forensic Medicine, Department of Forensic Toxicology, University of Bonn, Bonn, Germany.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Madea
mesh_terms: D002186:Cannabinoids / Q000032:analysis / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D004355:Drug Stability; D004356:Drug Storage; D005615:Freezing; D006801:Humans; D013287:Illicit Drugs / Q000032:analysis / Q000097:blood*; D013048:Specimen Handling; D015813:Substance Abuse Detection / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013696:Temperature
chemical_list: D002186:Cannabinoids; D013287:Illicit Drugs
keywords: Spice; freeze-thaw stability; liquid chromatography-tandem mass spectrometry; long-term stability; synthetic cannabinoids