Avaliação da interface de colisão e reação (CRI) na remoção de interferentes originados no preparo de amostras de solo por extração sequencial.

A extração sequencial de amostras de solo fornece informações importantes sobre a disponibilidade e mobilidade de elementos traço. A espectrometria de massa com plasma acoplado indutivamente (ICP-MS) é uma técnica analítica adequada para a determinação de elementos presentes em baixas concentrações, porém podem ocorrer interferências severas em meios complexos devido à formação de espécies poliatômicas. Visando corrigir ou eliminar esses efeitos algumas estratégias podem ser adotadas, tais como seleção de isótopos alternativos, correção pelo branco analítico, uso de plasma frio e introdução de gases reacionais e/ou colisionais, como H2 ou He, em celas ou na interface. O objetivo deste trabalho foi avaliar a interface de colisão e reação (CRI) na remoção de interferentes poliatômicos formados a partir do plasma de Ar e dos reagentes utilizados na extração sequencial (BCR) para a determinação de As, Cr e V

Sequential Extraction of Cr, Cu anel V in Soil anel Determination Using ICP·MS.

Among the instrumental techniques that can be useel for eletermination of trace elements in soils inductively coupled plaSl1la mass spectroscopy (ICP-MS) presents aelvantages such as multielemental character and superb sensitivity. However, aspects such as the content of total e1issolveel solids anel the polyatomic íons formeel in complex matrices may limit its application. The determination of Cr. Cu and V may suffer from polyatomic intelierences either originated in the argon plasma 01' in the matrix. In the case of 65Cu+ the main interferents are 23Na40Ar+ anel 23Na40Ca+ The eletermination of 52Cr+ is affecteel by 40Ar12C+ and 51V+ is affected by 35Cl16O+. Notwithstanding, all these elements also have less abundant isotopes not affected by severe interference processes

Acid vapor sample decomposition in open vessel microwave.

Micrawave decomposition has been increasingly used hr a large number of samples. A method using an open vessel microwave was used for biological sample preparation with nitric acid vapors under atmospheric pressure. A lab made Teflon@ support suited with four cups, which received the samples, was inserted in the microwave vessel. These cups were used to weight 30 mg of certi5ed re5wence materials such as spinach and apple leaves, which received 150 pL of d.i. water to improve the micrawave e%ciency. This mixture was exposed to acid vapor stemmed from 15 mL of concentrated nitrie acid plsced in the bottom of the vessel hr decompoeition. The maximum microwave temperature, 115'C, was reached in 4 min. This condition was rnaintained hr 20 min to sllow complete decomposition of the sample. The deeomposed sample, in the cup, was diluted to 1.0 mL of d.i. water, shaken and centrifuged. The cups were than placed directed into an autosampler for Co and Fe analysis in an atomic absorption graphite fumace spectrometer

Revisiting phage therapy: new applications for old resources

The success of phage therapy is dependent on the development of strategies able to overcome the limitations of bacteriophages as therapeutic agents, the creation of an adequate regulatory framework, the implementation of safety protocols, and the acceptance by the general public. Many approaches have been proposed to circumvent phages intrinsic limitations but none have proved to be completely satisfactory. In this review we present the major hurdles of phage therapy and the solutions proposed to circumvent them. A thorough discussion on the advantages and drawbacks of these solutions is provided and special attention is given to genetic modification of phages as an achievable strategy to shape bacteriophages to exhibit desirable biological properties.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project 'BioHealth - Biotechnology and Bioengineering approaches to improve health quality, Ref. NORTE-07-0124-FEDER-000027' cofunded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, and FEDER. F.L.N. also acknowledges the FCT for grant SFRH/BD/86462/2012