Date of Graduation
Eberly College of Arts and Sciences
Forensic and Investigative Science
Glen P Jackson
Stephen J Valentine
Casper H Venter
An alarming trend in the field of novel psychoactive substances (NPS) is the emergence of a class of synthetic phenethylamine derivatives known as NBOMes. These substances are low dosage hallucinogenic designer drugs that have become popular for recreational drug use, especially in Europe, Asia, and North America. The hallucinogenic effects of these substances are directly linked to the substitution and arrangement of the generic phenethylamine structure. An outbreak of deaths across the United States has prompted increased legislation to ban their distribution and use, but knowledge about NBOMes, and specifically the positional isomers, is lacking. In addition to identifying particular isomers of NBOMes, seized drug analysts would also benefit from a better understanding of the source of uncertainty in gas chromatography-mass spectrometry (GC-MS) measurements.;The analysis of six NBOMe isomers was conducted using both traditional and fast GC-MS for the development of characteristic retention times, retention indices, and fragment ion abundances. One-way analysis of variance (ANOVA) was used to evaluate the significance of different factors on the within-factor to between-factor variance. The factors assessed included positional isomers, concentration, day of analysis, week of analysis, instrument, speed of GC, and the recency of the tune profile. Additionally, principal component analysis (PCA) and canonical discriminant analysis (CDA) were used, respectively, to understand the sources of variance and assess the classification of NBOMe isomers based on the relative ion abundances.;Retention indices provided significantly large inter-isomer retention indices for the six NBOMe isomers studied, which means that all six isomers can be differentiated based on retention time. The measured retention indices established for the six isomers are as follows: 25C-NBOMe ortho 2614 +/- 15; 25C-NBOMe meta 2666 +/- 13; 25C-NBOMe para 2692 +/- 13; 25I-NBOMe ortho 2821 +/- 16; 25I-NBOMe meta 2877 +/- 15, and 25I-NBOMe para 2904 +/- 12.;The fast GC-MS method was twice as rapid as the traditional method, while providing no significant losses in GC resolutions or number of theoretical plates, which provides a compelling case for the future use of fast GC-MS in crime laboratories. In addition, Agilent fast GC provided retention time precision on the order of 0.03% RSD, compared to 0.10% RSD and 1.26% RSD for Agilent and PerkinElmer traditional GC-MS instruments. These measured precisions suggest that the commonly-adopted retention time match window of +/- 2% RSD may actually be too lenient. The CDA classification rate of 99.9% for the higher concentration samples and 99.5% for all concentration samples based on the relative ion abundances indicates a great potential for the application of multivariate classification for the identification of compounds with similar chemical structures. Finally, the determination that the effect of the tune profile does not significantly impact the relative ion abundances is significant to the quality assurance programs of crime labs.
Davidson, J. Tyler, "The Analysis of 2,5-Dimethoxy-N-(N-methoxybenzyl) phenethylamine (NBOMe) Isomers Using Traditional and Fast Gas Chromatography-Mass Spectrometry" (2017). Graduate Theses, Dissertations, and Problem Reports. 5438.