Citation

Maione C, de Oliveira Souza VC, Togni LR, da Costa JL, Campiglia AD, Barbosa F, Barbosa RM. J. Forensic Sci. 2017; 62(6): 1479-1486.

Affiliation

Instituto de Informática, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.

Copyright

(Copyright © 2017, American Society for Testing and Materials, Publisher John Wiley and Sons)

DOI

10.1111/1556-4029.13448

PMID

28205217

Abstract

The variations found in the elemental composition in ecstasy samples result in spectral profiles with useful information for data analysis, and cluster analysis of these profiles can help uncover different categories of the drug. We provide a cluster analysis of ecstasy tablets based on their elemental composition. Twenty-five elements were determined by ICP-MS in tablets apprehended by Sao Paulo's State Police, Brazil. We employ the K-means clustering algorithm along with C4.5 decision tree to help us interpret the clustering results. We found a better number of two clusters within the data, which can refer to the approximated number of sources of the drug which supply the cities of seizures. The C4.5 model was capable of differentiating the ecstasy samples from the two clusters with high prediction accuracy using the leave-one-out cross-validation. The model used only Nd, Ni, and Pb concentration values in the classification of the samples.

© 2017 American Academy of Forensic Sciences.

Language: en

Keywords

chemometrics; clustering; data mining; ecstasy; forensic science; forensic toxicology; inductively coupled plasma mass spectrometry