TECHNICAL NOTE CRIMINALISTICS Ciro A. F. O. Penido, 1 M.Sc.; Marcos Tadeu T. Pacheco, 1 Ph.D.; Renato A. Z^ angaro, 1 Ph.D.; and Landulfo Silveira, Jr., 1 Ph.D. 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 adul- terants used to increase volume, and possible degradation products in samples seized by the police. Near-infrared Raman spectra (785 nm exci- tation, 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 benzoylecgo- nine 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. KEYWORDS: forensic science, cocaine identification, adulterant, degradation, Raman spectroscopy, Fourier transform–infrared spectros- copy, toxicology Cocaine is an alkaloid stimulant of the central nervous system extracted from native species of South America, Erythroxylon coca and Erythroxylon novogranatense (1). Common forms of cocaine that are used for drug addiction include freebase powder (for inhalation), hydrochloride powder (for venous injection), freebase paste and crack rock (both for smoking). Cocaine abuse is currently a major global issue in terms of public security and health. Numerous health complications are associated with acute and chronic use of cocaine. There are case reports of strokes resulting from overdose, in which cocaine with higher purity is consumed by users unaware of the drug’s actual concentration (2). Furthermore, various adulterants are mixed with cocaine that are used to increase the volume. These adulterants are often del- eterious to health and are mainly consumed along with the drug in the crack form. Discriminating the various forms of cocaine (freebase powder or paste, hydrochloride powder, and crack rock), the drug’s true concentration, and the adulterants used to increase volume is of great interest to the forensic toxicology field as a means of conclusively identifying drugs in cases of drug trafficking (3–5). Current methods employed in forensic toxicology, such as gas chromatography and flame ionization detection (GC-FID), aim to detect and identify illicit drugs such as cocaine, ampheta- mines, MDMA (ecstasy), opiates, barbiturates, and benzodiaze- pines. Despite their high reliability, these methods are destructive, time-consuming, and do not allow reexamination of the evidence (6,7). Nondestructive and rapid analysis of drugs of abuse could be accomplished through the use of vibrational spectroscopic tech- niques, especially infrared absorption spectroscopy (FT-IR) and Raman spectroscopy (4,8,9). The advantages lie in the possibility of rapid analysis of trace samples from a crime scene and after seizing drugs, without the destruction of evidence. Thus, these techniques may become a powerful instrument in the fight against drug trafficking (1). Raman spectroscopy is a technique based on the inelastic scat- tering of laser light molecules and has been used for qualitative and quantitative analysis of drugs of abuse and their adulterants. One can perform a molecular analysis in seconds, without the use of toxic chemicals and without direct contact with the sam- ple (1,9–11). Using near-infrared excitation, most sample fluo- rescence is minimized. Raman bands of cocaine and common adulterants have been reported in the literature (1,12–16). FT-IR is a technique based on absorption in the infrared region by a molecule due to variations in the dipole moment during vibration. Together with an accessory used to perform measurements by attenuated total reflectance (ATR), this method has been employed for the analysis of trace compounds and con- taminants (17). Recent studies using FT-IR have included the 1 Biomedical Engineering Institute, Universidade Camilo Castelo Branco - UNICASTELO, Parque Tecnol ogico de S~ ao Jos e dos Campos, Estrada Dr. Altino Bondesan, 500, Eug^ enio de Melo, S~ ao Jos e dos Campos, SP 12247-016, Brazil. *Supported in part by FAPESP (S~ ao Paulo Research Foundation) who granted the Raman instrument (Process no. 2009/01788-5). Received 14 Feb. 2013; and in revised form 25 Sept. 2013; accepted 23 Nov. 2013. 171 © 2014 American Academy of Forensic Sciences J Forensic Sci, January 2015, Vol. 60, No. 1 doi: 10.1111/1556-4029.12666 Available online at: onlinelibrary.wiley.com