Quantification Of Sterol And Triterpenol Biomarkers In Sediments Of The Cananeia-iguape Estuarine-lagoonal System (brazil) By Uhplc-ms/ms

Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananeia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananeia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve

Probing the mechanism of the Ugi four-component reaction with charge-tagged reagents by ESI-MS(/MS)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The mechanism of the Ugi four-component reaction has been investigated by electrospray ionization (tandem) mass spectrometry using charge-tagged reagents (a carboxylic acid or an amine) to favour detection. Key intermediates were transferred directly via ESI(+) from the reaction solution to the gas phase and characterized by MS measurements and MS/MS collision induced dissociation. The Mumm rearrangement (final step) was also investigated by both travelling wave ion mobility mass spectrometry and DFT calculations. The data seem to consolidate the amazingly selective mechanism of this intricate four-component reaction.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.503338340FAPDFCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FINATECDPP-UnBCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Task-specific ionic liquid incorporating anionic heteropolyacid-catalyzed Hantzsch and Mannich multicomponent reactions. Ionic liquid effect probed by ESI-MS(/MS)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A task-specific ionic liquid with a Bronsted acid (1-(3-sulfopropyI)-3-methylimidazolium hydrogen sulfate, namely MSI) bearing an anionic heteropolyacid derivative ([PW12O40](3-), namely PW) were used as an efficient catalyst for the three-component Mannich and Hantzsch reactions. Using (MSI)(3)PW as the catalyst supported in imidazolium-based ionic liquids allowed these multicomponent reactions to take place in good to excellent yields. The Mannich reaction, performed at room temperature, was also evaluated by means of electrospray (tandem) mass spectrometry ESI-MS(/MS). ESI-MS data pointed to the origin of the ionic liquid effect, i.e., formation of ion pairs with the charged reaction intermediates and furthers association into larger supramolecular aggregates. DFT calculations revealed the strength of the supramolecular interactions between the charged species detected by ESI-MS and the spontaneity association of these ion pairs affording larger supramolecular aggregates. (C) 2013 Elsevier Ltd. All rights reserved.702033063313Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FINEPMCTFINATECFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPDFDPP-UnBINCT-CatalysisINMETROANP-PETROBRASCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP