ИДЕНТИФИКАЦИЯ НЕИЗВЕСТНОГО КОМПОНЕНТА ЭКСТРАКТА ВОЛОС ЭКСГУМИРОВАННЫХ ЧЕЛОВЕЧЕСКИХ ОСТАНКОВ ПО МАСС-СПЕКТРОМЕТРИЧЕСКИМ И ГАЗОХРОМАТОГРАФИЧЕСКИМ ДАННЫМ

Abstract

The real example of GC-MS identification of unknown constituent of human hair extract belonging to the exhumed remains is considered. The identification of this constituent (molecular weight 238 Da) was unsuccessful using both its standard mass spectrum (electron ionization) in combination with lib\xadra\xadry search, and its GC retention index value (~1540 on semi-standard non-polar polydimethyl siloxane stationary phases with 5% phenyl groups). However, its identification appea\xadred to be possible using the original algorithm of data processing. This approach implies revealing the structural analogues of unknown analytes, primarily their homologues which differ by molecular masses on ± 14 Da and by composition on CH 2 homolo\xadgo\xadus difference. This approach allowed revealing such analogues of unknown analyte as Flavesone (2,2,4,4-tetramethyl-2-isobutyrylcyclohexa-1,3,5-trione), Leptospermone (2,2,4,4-tetramethyl-2-isopentanoylcyclohexa-1,3,5-trione), and some others. All these compounds belong to a rather “exotic” class of natural compounds knows as cyclic b-triketones. Based on the obtained data, the possible structure of the constitu\xadent under the consideration was proposed as 2,2,4,4-tetramethyl-2-propionylcyclohexa-1,3,5-trione. The principal fea\xadture of cyclic b-triketones is their existence in a few tautomeric forms. Another tautomer of triketone under discussion is 5-hydroxy-2,2,6,6-tetramethyl-4-propionyl-4-en-1,3-dio\xadne (CAS № 87552-01-0). This compound is found to be the constituent of Leptosper\xadmum scoparium essential oil and some other plants, and it belongs to the group of structural analogues of Flave\xadsone. The most known pharmaceutical application of essential oils containing these compounds are the components of conditioners for hair and skin. The results confirm this formerly un\xadknown component does not belong to the group of toxic substances. This excludes the criminal origin of the remains. Keywords : Human hair extract, unknown constituent, gas chromatography – mass spect\xadro\xadmetry, identification, 2,2,4,4-tetrtamethyl-5-propionylcyclohexa-1,3,5-trione DOI: http://dx.doi.org/10.15826/analitika.2021.25.1.002 Sergei A. Savchuk 1 ,\xa0 Igor G. Zenkevich 2 1 Russian center of forensic expertise, Russian Ministry of Health, Polikarpova str., 12/13, Moscow 125284, Russian Federation 2 St. Petersburg State University, Institute for Chemistry, Universitetskii prosp., 26, St. Petersburg, 198504, Russian Federation