title: Fast profiling of cocaine seizures by FTIR spectroscopy and GC-MS analysis of minor alkaloids and residual solvents.
abstract: In this study, samples coming from large seizures of cocaine which took place in Italian Customs areas during 2011 and 2012 were examined. Minor alkaloids and residual solvents, analyzed by gas chromatography-mass spectrometry (GC-MS) and head space (HS)-GC-MS, respectively, were processed by principal component analysis (PCA), highlighting groupings of samples according to their chemical similarity. A hypothesis about the geographical origin of samples was also provided: most of them were compatible with Colombia as country of origin. Results of these analyses were used as starting point for the development of a "fast profiling" method, based on Fourier transform infrared spectroscopy (FTIR) and chemometric tools. Two models were developed and compared: KBr-FTIR and attenuated total reflection (ATR)-FTIR for comparative analysis of pure samples. Linear discriminant analysis (LDA) was applied to the model based on ATR-FTIR spectroscopy, obtaining a classification and a prediction ability both of 97.56% for pure samples. Finally, "cut" samples were tested as an external test set, and the assignment class provided by LDA was compared with results obtained by the analyses of alkaloids and residual solvents: in the case of samples added with only one substance, prediction errors began to occur for percentages of cocaine lower than 50%.
authors.affiliation: Central Directorate for Product Analysis and Chemical Laboratories, Italian Customs and Monopolies Agency, via M. Carucci 71, 00143 Rome, Italy. Electronic address: maria.monfreda@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Monfreda
authors.affiliation: Central Directorate for Product Analysis and Chemical Laboratories, Italian Customs and Monopolies Agency, via M. Carucci 71, 00143 Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Varani
authors.affiliation: Central Directorate for Product Analysis and Chemical Laboratories, Italian Customs and Monopolies Agency, via M. Carucci 71, 00143 Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Cattaruzza
authors.affiliation: Central Directorate for Product Analysis and Chemical Laboratories, Italian Customs and Monopolies Agency, via M. Carucci 71, 00143 Rome, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Ciambrone
authors.affiliation: Central Directorate for Product Analysis and Chemical Laboratories, Italian Customs and Monopolies Agency, via M. Carucci 71, 00143 Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Proposito
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives* / Q000737:chemistry*; D064423:Drug Trafficking; D053593:Forensic Toxicology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009294:Narcotics / Q000737:chemistry*; D025341:Principal Component Analysis; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009294:Narcotics; D003042:Cocaine
keywords: ATR-FTIR; Cocaine; Drug profiling; KBr-FTIR; LDA; PCA