Publications by authors named "Marta I S Verissimo"

This work aims to assess the surface coupling of molecularly imprinted polymers (MIP) on carbon adsorbents produced from spent brewery grain, namely biochar (BC) and activated carbon (AC), as a strategy to improve selectivity and the adsorptive removal of the antibiotic sulfamethoxazole (SMX) from water. BC and AC were produced by microwave-assisted pyrolysis, and MIP was obtained by fast bulk polymerization. Two different methodologies were used for the molecular imprinting of BC and AC, the resulting materials being tested for SMX adsorption.

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Polyoxometalates (POMs) are a class of metal oxide complexes with a large structural diversity. Effective control of the final chemical and physical properties of POMs could be provided by fine-tuning chemical modifications, such as the inclusion of other metals or non-metal ions. In addition, the nature and type of the counterion can also impact POM properties, like solubility.

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A sensor consisting of an optical fibre with the exposed tip coated with the polyoxometalate salt [(CH)N]H[PMoVO], specially designed to be insoluble in water, which UV-Vis spectrum changed in contact with formaldehyde, is presented. The sensor limit of detection for formaldehyde was 0.2 mg L, and the limit of quantification was 0.

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The identification of paper composition, pH, early signs of paper degradation, and emitting volatile organic compounds (VOCs) are mandatory for effective preventive conservation of paper/books. Sampling restrictions in the analysis of cultural heritage materials limit the choice of appropriate analytical methods. Solvent-free analytical techniques with nondestructive sampling are needed.

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Pseudomonas aeruginosa (P. aeruginosa) possesses intracellular amidase activity, which catalyses the hydrolysis of short aliphatic amides producing NH4+, and has already been used along with an ammonium ion selective electrode for amide quantification. However, the incorporation of a biological membrane turned to be a challenging process and either the final arrangement was prone to amidase losses or the recovery of the sensor coating after the interaction took too long.

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In this work, the -confused porphyrin 5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrin (NCTPP) was immobilized on neutral or cationic supports based on silica and on Merrifield resin. The new materials were characterized by appropriate techniques (UV-Vis spectroscopy, SEM, and zeta potential analysis). Piezoelectric quartz crystal gold electrodes were coated with the different hybrids and their ability to interact with heavy metals was evaluated.

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High concentrations of 5-hydroxymethylfurfural (HMF) in honey provide an indication of overheating under inappropriate storage conditions or aging. Conventional methods for determining HMF are cumbersome and require expensive equipment or hazardous reagents. Hence the aim of this study was to propose a new analytical tool for HMF determination in honey, using a low cost acoustic wave sensor.

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Aluminium (Al) migration from cans to beer and tea was studied along time. Analyses of Al in the canned drinks were performed till the sell-by date, and, in seven months, aluminium migration was found to increase 0.14 mg L(-1) in beer, and 0.

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A new methodology based on an inexpensive aluminium acoustic wave sensor is presented. Although the aluminium sensor has already been reported, and the composition of the selective membrane is known, the low detection limits required for the analysis of drinking water, demanded the inclusion of a preconcentration stage, as well as an optimization of the sensor. The necessary coating amount was established, as well as the best preconcentration protocol, in terms of oxidation of organic matter and aluminium elution from the Chelex-100.

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