RESUMO
RATIONALE: There is a need for fast, post-ionization separation during the analysis of complex mixtures. In this study, we evaluate the use of a high-resolution mobility analyzer with high-resolution and ultrahigh-resolution mass spectrometry for unsupervised molecular feature detection. Goals include the study of the reproducibility of trapped ion mobility spectrometry (TIMS) across platforms, applicability range, and potential challenges during routine analysis. METHODS: A TIMS analyzer was coupled to time-of-flight mass spectrometry (TOF MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) instruments for the analysis of singly charged species in the m/z 150-800 range of a complex mixture (Suwannee River Fulvic Acid Standard). Molecular features were detected using an unsupervised algorithm based on chemical formula and IMS profiles. RESULTS: TIMS-TOF MS and TIMS-FT-ICR MS analysis provided 4950 and 7760 m/z signals, 1430 and 3050 formulas using the general Cx Hy N0-3 O0-19 S0-1 composition, and 7600 and 22 350 [m/z; chemical formula; K; CCS] features, respectively. CONCLUSIONS: TIMS coupled to TOF MS and FT-ICR MS showed similar performance and high reproducibility. For the analysis of complex mixtures, both platforms were able to capture the major trends and characteristics; however, as the chemical complexity at the level of nominal mass increases with m/z (m/z >300-350), only TIMS-FT-ICR MS was able to report the lower abundance compositional trends.
RESUMO
About 30 studies from the published literature were reviewed to determine the pollution status regarding heavy metals and organic compounds of the Wider Caribbean Region (WCR). The literature revealed that most studies were performed in the South and Central American Caribbean Region with sparse reports on the small island states. Collectively, the most frequently analyzed heavy metals were Pb, Cu, Zn, Fe, Cd, Ni, Mn and Cr while DDT and its metabolites were the most frequently reported organic pollutants. The samples which were analyzed vary in terms of sampling schemes, parameters and analytical techniques, as well as differences in data reporting presentation (i.e. dry weight versus wet weight, sediment fraction analyzed, or % lipids). These differences make meaningful comparisons of the available data very difficult. Furthermore, there is limited data available for most of these contaminants from the majority of nations in the WCR. Therefore, any attempt to create a regional scale assessment from contaminants data available in the open literature is limited by the scarcity of available information.
Assuntos
Evolução Biológica , Ecossistema , Monitoramento Ambiental , Metais Pesados/análise , Compostos Orgânicos/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Animais , Região do Caribe , América Central , Geografia , Oceanos e Mares , Praguicidas/análise , População , Medição de Risco , América do SulRESUMO
Surface sediments throughout Montego Bay, Jamaica were collected in 1995 and analyzed for their trace metal and trace organic contaminant content. A variety of trace metals, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, coprostanol as well as chlorinated hydrocarbons such as pesticides and polychlorinated biphenyls were detected and provide evidence for several anthropogenic inputs to the bay. Two main sources of these chemicals are the Montego River and the North Gully, the latter being more significant. Particle-associated pollutants were found to be distributed along the Montego River plume, as well as being transported by the prevailing water currents to the South-Western sections of the bay, probably through re-suspension of enriched fine sediments from the North Gully outfall area.