Identification of Different Forms of Cocaine and Substances Used in Adulteration Using Near-infrared Raman Spectroscopy and Infrared Absorption Spectroscopy
-
Ciro A. F. O. Penido [1] ; Marcos Tadeu T. Pacheco [1] ; Renato A. Zângaro [1] ; Landulfo Silveira [1]
-
[1] Universidade Camilo Castelo Branco
Universidade Camilo Castelo Branco
Brasil
-
- Localización: Journal of forensic sciences, ISSN-e 1556-4029, ISSN 0022-1198, Vol. 60, Nº. 1, 2015, págs. 171-178
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
-
Resumen
Identification of cocaine and subsequent quantification immediately after seizure are problems for the police in developing countries such as Brazil. This work proposes a comparison between the Raman and FT-IR techniques as methods to identify cocaine, the adulterants used to increase volume, and possible degradation products in samples seized by the police. Near-infrared Raman spectra (785 nm excitation, 10 sec exposure time) and FT-IR-ATR spectra were obtained from different samples of street cocaine and some substances commonly used as adulterants. Freebase powder, hydrochloride powder, and crack rock can be distinguished by both Raman and FT-IR spectroscopies, revealing differences in their chemical structure. Most of the samples showed characteristic peaks of degradation products such as benzoylecgonine and benzoic acid, and some presented evidence of adulteration with aluminum sulfate and sodium carbonate. Raman spectroscopy is better than FT-IR for identifying benzoic acid and inorganic adulterants in cocaine
