Potentialities of two solventless extraction approaches—Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines

A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE-LD/LVI-GC–qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min−1 for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03–28.96 μg L−1) and HS-SPME (0.02–20.29 μg L−1) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 μg L−and from 0.06 to 67.63 μg L−1 for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The analytical and procedural advantages and disadvantages of these two methods have been compared. Both analytical methods were used to determine the HAA, IsoE and EE fatty acids content in “Terras Madeirenses” table wines. A total of 16 esters were identified and quantified from the wine extracts by HS-SPME whereas by SBSE-LD technique were found 25 esters which include 2 higher alcohol acetates, 4 isoamyl esters and 19 ethyl esters of fatty acids. Generally SBSE-LD provided higher sensitivity with decreased analysis time.

Relatório de estágio para obtenção do grau de mestre em Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico

O presente relatório foi elaborado para a obtenção do grau de mestre em Educação PréEscolar e Ensino do 1º Ciclo do Ensino Básico. Este foi construído em torno da intervenção pedagógica desenvolvida no contexto de Educação Pré-Escolar, no Infantário “O Carrocel”, e no contexto de 1º Ciclo do Ensino Básico, na Escola Básica do 1º Ciclo com Pré-Escolar da Achada. Na primeira parte é feita uma abordagem ao enquadramento teórico, legislativo e metodológico, sendo que estes fundamentaram a intervenção pedagógica. Numa outra parte é apresentada a intervenção pedagógica, que teve como importante recurso a investigação-ação. Esta distinta metodologia promove atitudes de reflexão que permitem que sejam pensadas e utilizadas estratégias durante a práxis, tentando envolver as crianças numa aprendizagem de caráter ativo e significativo, tendo sempre em atenção as suas necessidades e interesses. No fim serão apresentadas reflexões críticas acerca da intervenção pedagógica realizada nos contextos de Educação Pré-Escolar e de 1º Ciclo, dando também resposta às questões incluídas nos projetos de Investigação-Ação desenvolvidos. Deste modo, este relatório acaba por apresentar a importância que a intervenção pedagógica possui na construção da identidade profissional em contexto de formação inicial.