Structural elucidation of phenidate analogues via the ESI-MS/MS spectra of their sodium adduct ions. (January 2020)

• Record Type: Journal Article
• Authors: Shamai Yamin, Tamar; Prihed, Hagit; Madmon, Moran; Shifrovitch, Avital; Baratz, Adva; Weissberg, Avi
• Is Part Of: Forensic science international. Volume 306(2020)
• Publication Date: 2020-01
• Subjects: LC-ESI-MS/MS -- Phenidate analogues -- Structural elucidation -- Sodium adduct -- Forensic toxicology; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2019.110044
• Languages: English
• ISSNs: 0379-0738

Abstract

Graphical abstract: Highlights: EI-MS and ESI-MS/MS spectra of [M+H] + of phenidate analogues are uninformative. Different fragmentation patterns between [M+H] + and [M+Na] + were observed. Structural information of phenidates was achieved only by ESI-MS/MS spectra of [M+Na] + . Improved identification of novel phenidate analogues in water and urine was achieved. Abstract: The identification of phenidate new psychoactive substances (NPS) by implementing MS (Mass spectrometry) techniques is a challenging task. Phenidate analogues present information-poor mass spectra, both in GC-EI-MS and LC-ESI-MS/MS of the protonated molecules [M+H] +, with a high abundance fragment/product ion representing the secondary amine-containing residue. This lack of EI-MS and ESI-MS/MS information is attributed to the strong tendency of the amine residue to stabilize the positive charge and leads to unavoidable ambiguity in the identification process. Moreover, thermal decomposition of these compounds occurs in the injection port and/or on the column under standard GC conditions. Herein, we demonstrate how structural information can be attained instantaneously through the LC-ESI-MS/MS fragmentation of the accompanied sodium adducts [M+Na] + . The sodium cation alters the charge distribution during ESI-MS/MS fragmentation, generating a major product ion corresponding to the Na + adduction of the carbonyl group, providing new structural information of the main core of phenidate derivatives (alkylaryl acetate/acetic acid), enabling their reliable structural elucidation. This quick, simple and easy technique can be implemented to confirm the identity or identify various structurally related phenidate analogues in forensic toxicology and doping analysis without the need for sample handling.