Levantamento de práticas ambientais e energéticas de PMEs em Portugal

Para qualquer empresa o seu maior objetivo passa pela produção de lucro e, atualmente, esse aspeto está diretamente relacionado com a sua capacidade de manter uma gestão que incorpore a responsabilidade social, ambiental e económica, em prol de um desenvolvimento global mais sustentável. As grandes empresas já iniciaram e continuam este processo de mudança, desenvolvendo medidas e estratégias neste sentido. Porém, apesar de representarem o grosso do tecido empresarial, as Pequenas e Médias Empresas só agora começam a dar os primeiros passos em direção a uma gestão mais ponderada ambiental e energeticamente. Com este trabalho pretende-se reunir informação relativa às Pequenas e Médias Empresas portuguesas de forma a compreender quais as principais áreas de atuação, as medidas que poderão ser implementadas e, consolidar o ponto de situação deste sector acerca dos vários temas ao nível do meio ambiente e da energia. Para tal, foram realizados levantamentos energéticos e aplicado um questionário acerca dos comportamentos e práticas ambientais. Verificou-se que apesar da grande maioria das empresas analisadas já terem ponderado a importância e as vantagens da eficiência energética, ainda são poucas as organizações que têm implementados planos, estratégias ou instrumentos para melhoria do seu desempenho ambiental e energético.

Novel biosensing device for point-of-care applications with plastic antibodies grown on Au-Screen Printed Electrodes

A gold screen printed electrode (Au-SPE) was modified by merging Molecular Imprinting and Self-Assembly Monolayer techniques for fast screening cardiac biomarkers in point-of-care (POC). For this purpose, Myoglobin (Myo) was selected as target analyte and its plastic antibody imprinted over a glutaraldehyde (Glu)/cysteamine (Cys) layer on the gold-surface. The imprinting effect was produced by growing a reticulated polymer of acrylamide (AAM) and N,N′-methylenebisacrylamide (NNMBA) around the Myo template, covalently attached to the biosensing surface. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) studies were carried out in all chemical modification steps to confirm the surface changes in the Au-SPE. The analytical features of the resulting biosensor were studied by different electrochemical techniques, including EIS, square wave voltammetry (SWV) and potentiometry. The limits of detection ranged from 0.13 to 8 μg/mL. Only potentiometry assays showed limits of detection including the cut-off Myo levels. Quantitative information was also produced for Myo concentrations ≥0.2 μg/mL. The linear response of the biosensing device showed an anionic slope of ~70 mV per decade molar concentration up to 0.3 μg/mL. The interference of coexisting species was tested and good selectivity was observed. The biosensor was successfully applied to biological fluids.

3D-nanostructured Au electrodes for the event-specific detection of MON810 transgenic maize

In the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis.

“Green Electrodes” Modified with Au Nanoparticles Synthesized in Glycerol, as Electrochemical Nitrite Sensor

A new environmentally friendly Au nanoparticles (Au NPs) synthesis in glycerol by using ultraviolet irradiation and without extra-added stabilizers is described. The synthesis proposed in this work may impact on the non-polluting production of noble nanoparticles with simple chemicals normally found in standard laboratories. These Au NPs were used to modify a carbon paste electrode (CPE) without having to separate them from the reaction medium. This green electrode was used as an electrochemical sensor for the nitrite detection in water. At the optimum conditions the green sensor presented a linear response in the 2.0×10−7–1.5×10−5 M concentration range, a good detection sensitivity (0.268 A L mol−1), and a low detection limit of 2.0×10−7 M of nitrite. The proposed modified green CPE was used to determine nitrite in tap water samples.