We report for the first time the efficient use of accelerated solvent extraction (ASE) for extraction of ricin to analytical purposes, followed by the combined use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and MALDI-TOF MS/MS method. That has provided a fast and unambiguous method of ricin identification for in real cases of forensic investigation of suspected samples. Additionally, MALDI-TOF MS was applied to characterize the presence and the toxic activity of ricin in irradiated samples. Samples containing ricin were subjected to ASE, irradiated with different dosages of gamma radiation, and analyzed by MALDI-TOF MS/MS for verification of the intact protein signal. For identification purposes, samples were previously subjected to SDS-PAGE, for purification and separation of the chains, followed by digestion with trypsin, and analysis by MALDI-TOF MS/MS. The results were confirmed by verification of the amino acid sequences of some selected peptides by MALDI-TOF MS/MS. The samples residual toxic activity was evaluated through incubation with a DNA substrate, to simulate the attack by ricin, followed by MALDI-TOF MS/MS analyses.
Gas chromatography simultaneously coupled to flame photometric detector, nitrogen phosphorus detector and mass spectrometer (GC/FPD/NPD-MS) was used to identify nitrogen and sulfur mustards, their precursors and degradation products in samples of water, soil, organic solvent and a PVC floor. Extraction techniques and derivatization with BSTFA were employed during sample preparation. Fast screening of the samples was possible due the high sensibility and selectivity of FPD and NPD for sulfur and nitrogen compounds. Mass spectra of the identified chemicals presented match factors equal or bigger than 90% when compared to OPCW databases.Keywords: Mustard gas; gas chromatography; mass spectrometry; chemical weapons.
ResumoCromatografia gasosa acoplada simultaneamente a detectores fotométricos de chama, de nitrogênio e fósforo e espectrômetro de massas (CG/DFC/DNP-EM) foi utilizada na identificação de mostardas de enxofre e de nitrogênio, seus precursores e produtos de degradação em amostras de água, solo, solvente orgânico e um piso de PVC preparadas de forma controlada. Técnicas de extração e derivatização com BSTFA foram utilizadas para possibilitar as análises das substâncias por cromatografia gasosa. O uso simultâneo de vários detectores em um só equipamento possibilitou rapidez nas análises. DFC e DNF apresentam boa seletividade e sensibilidade para compostos contendo enxofre e nitrogênio, permitindo a seleção inicial dos picos cromatográficos de possíveis compostos de interesse. Todos os espectros de massa das substâncias identificadas apresentaram índices de similaridades iguais ou superiores a 90% quando comparados aos existentes nas bases de dados da OPAQ.Palavras-chave: Gás mostarda; cromatografia gasosa; espectrometria de massas; armas químicas.
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