Espectrometria de massas por paper spray Ionization: técnica analítica versátil para os desafios da química forense
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2018-10-05
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Universidade Federal de Goiás
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Ionization is a crucial step in mass spectrometry (MS) and governs the versatility of this important analytical technique. Ionization is responsible for transferring atoms and molecules, in their respective ionized forms, into the high vacuum environment of mass spectrometers, where they are discriminated as a function of their m/z ratio. Among the several techniques of ionization of MS, the technique of ionization by Paper spray (PS) is one of the simplest, versatile and can be implemented easily in MS system. In this work, several PS-MS applications in the forensic area were developed, demonstrating their ability to screen new synthetic drugs as a complementary tool to the thin layer chromatography (TLC) method and as a tool to monitor Date-rape Drugs in blood. In the first application, PS-MS was shown to be an effective and rapid method for the identification of synthetic drugs lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-chloroamphetamine (DOC), 2,5-dimethoxy-4-bromoamphetamine (DOB), 25C-NBOMe, 25B-NBOMe and 25I-NBOMe) in bottles, both by the isotopic profile of the substances and by the fragmentation presented in tandem mass spectrometry. In the second application, the TLC was coupled to the PS-MS in order to achieve greater reliability in the CCD results. In this way, a CCD method for the analysis of cocaine and adulterants (caffeine, benzocaine, lidocaine and phenacetin) was optimized by evaluating its sensitivity and selectivity. In order to improve the Detection and Quantification Limits for cocaine and adulterants, the spots were analyzed by PS-MS, obtaining improvements in the. Finally, in order to solve the low PS-MS selectivity, a new substrate was developed, especially when the analytical target is in complex mixtures, such as blood. It is a membrane coated with a molecularly printed polymer (MIP) with dual function: simultaneous extraction and ionization of targets in the same device. The developed membrane was applied in the determination of benzodiazepines in blood samples from alleged date rape- drugs victims. Blood is a complex sample containing several compounds that can suppress the analyte signal. With this modification, any suppression is avoided, obtaining excellent results, both qualitative and quantitative. In conclusion, PS-MS is a fast and low-cost technique that can replace or complement conventional analyzes in a laboratory of expertise, increasing the productivity of Brazilian justice.
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CARVALHO, T. C. Espectrometria de massas por paper spray Ionization: técnica analítica versátil para os desafios da química forense. 2018. 107 f. Tese (Doutorado em Química) - Universidade Federal de Goiás, Goiânia, 2018.