Identification of Different Forms of Cocaine and Substances Used in Adulteration Using Near‐infrared Raman Spectroscopy and Infrared Absorption Spectroscopy |
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| Authors: | Ciro A F O Penido MSc Marcos Tadeu T Pacheco PhD Renato A Zângaro PhD Landulfo Silveira PhD Jr |
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| Affiliation: | 1. Biomedical Engineering Institute, Universidade Camilo Castelo Branco ‐ UNICASTELO, Parque Tecnológico de S?o José dos Campos, Estrada Dr. 2. Altino Bondesan, 500, Eugênio de Melo, S?o José dos Campos, SP, 12247‐016 Brazil;3. Additional information and reprint requests:;4. Landulfo Silveira, Jr, Ph.D.;5. Professor;6. Universidade Camilo Castelo Branco – UNICASTELO;7. Parque Tecnológico de S?o José dos Campos;8. Estr. Dr. Altino Bondesan, 500, Eugênio de Melo;9. S?o José dos Campos, SP, Brazil, 12247‐016;10. E‐mail: |
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| Abstract: | 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. |
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| Keywords: | forensic science cocaine identification adulterant degradation Raman spectroscopy Fourier transform– infrared spectroscopy toxicology |
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