title: Identification of different forms of cocaine and substances used in adulteration using near-infrared Raman spectroscopy and infrared absorption spectroscopy.
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.
authors.affiliation: Biomedical Engineering Institute, Universidade Camilo Castelo Branco - UNICASTELO, Parque Tecnológico de São José dos Campos, Estrada Dr. Altino Bondesan, 500, Eugênio de Melo, São José dos Campos, SP, 12247-016, Brazil.
authors.forename: Ciro A F O
authors.initials: CA
authors.lastname: Penido
authors.forename: Marcos Tadeu T
authors.initials: MT
authors.lastname: Pacheco
authors.forename: Renato A
authors.initials: RA
authors.lastname: Zângaro
authors.forename: Landulfo
authors.initials: L
authors.lastname: Silveira
mesh_terms: D003042:Cocaine / Q000737:chemistry*; D018765:Dopamine Uptake Inhibitors / Q000737:chemistry*; D004340:Drug Contamination; D006801:Humans; D013287:Illicit Drugs / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D018765:Dopamine Uptake Inhibitors; D013287:Illicit Drugs; D003042:Cocaine
keywords: Fourier transform-infrared spectroscopy; Raman spectroscopy; adulterant; cocaine identification; degradation; forensic science; toxicology