Browsing by Author "Pereira, Mafalda G."
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- Amostragem inteligente como abordagem expedita para monitorização de iões de metal em águas naturais: projeto Aqua_SmartPublication . Pereira, Mafalda G.; Melo, Maria M. P.; Mesquita, Raquel B. R.; Ribas, Tânia C. F.; Machado, Ana; Rangel, António O. S. S.
- Amostragem inteligente como abordagem expedita para monitorização de iões de metal em águas naturais: projeto Aqua_SmartPublication . Pereira, Mafalda G.; Melo, Maria M. P.; Mesquita, Raquel B. R.; Ribas, Tânia; Machado, Ana; Rangel, António O. S. S.O projeto Aqua_Smart (FCT ref. 2022.08713.PTDC) foi concebido com o objetivo de desenvolver um conceito de amostragem inteligente integrada numa monitorização automática do teor de iões potencialmente tóxicos em águas, permitindo monitorizar alterações ambientais que podem ter impacto na saúde pública, promovendo uma abordagem “One Health”. Neste trabalho reporta-se a utilização de uma PIM como suporte de troca aniónica, explorando a tendência para formar cloro complexos de cobalto, permitindo a determinação deste ião. Neste enquadramento, tornou-se relevante combinar com a determinação do teor em anião cloreto, usando um reagente colorimétrico de baixa toxicidade.
- Chloride catalytic determination as potential tool to assess metal ion bioavailability in waterPublication . Pereira, Mafalda G.; Paluch, Justyna; Mesquita, Raquel B. R.; Rangel, António O. S. S.This paper focuses on the development of an environmentally friendly sequential injection (SI) method for the determination of chloride in water samples from dynamic water systems. Chloride quantification is highly relevant, as it may affect metal ion bioavailability and potential toxicity to the environment. The approach was established based on the catalytic reaction of chloride ions in the colorimetric reaction between 3,3′,5,5′-tetramethylbenzidine (TMB) and hydrogen peroxide. Optimisation studies were performed regarding several parameters such as reaction pH, reagent volume and concentration, reaction time, and flow rates. As such, it was possible to obtain a wide dynamic range of 60 to 1000 mM, with a limit of detection and quantification of 17 and 58 mM, respectively, and a relative standard deviation of 7%. Validation was performed by analysing 13 water samples from dynamic water systems, namely seawater, estuarine water, and estuarine harbour water, with the SI method developed and by comparing the results obtained to potentiometric titration as the reference method. The relative error of these comparisons was not significant (<10%). Interference studies were also performed and showed no significant effect on the performance of the system (interference percentage < 10%), proving that a robust and sensitive system was developed.
- Development of a microfluidic paper-based analytical device for the determination of iodidePublication . Pereira, Mafalda G.; Rangel, António O. S. S.; Mesquita, Raquel B. R.
- Development of a microfluidic paper-based analytical device for the determination of iodidePublication . Pereira, Mafalda G.; Rangel, António O. S. S.; Mesquita, Raquel B. R.
- Microfluidic paper-based device incorporated with silica nanoparticles for iodide quantification in marine source dietary supplementsPublication . Pereira, Mafalda G.; Machado, Ana; Leite, Andreia; Rangel, Maria; Bordalo, Adriano; Rangel, António O. S. S.; Mesquita, Raquel B. R.Iodine is an essential micronutrient for humans due to its fundamental role in the biosynthesis of thyroid hormones. As a key parameter to assess health conditions, iodine intake needs to be monitored to ascertain and prevent iodine deficiency. Iodine is available from various food sources (such as seaweed, fish, and seafood, among others) and dietary supplements (multivitamins or mineral supplements). In this work, a microfluidic paper-based analytical device (μPAD) to quantify iodide in seaweed and dietary supplements is described. The developed μPAD is a small microfluidic device that emerges as quite relevant in terms of its analytical capacity. The quantification of iodide is based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by hydrogen peroxide in the presence of iodine, which acts as the catalyst to produce the blue form of TMB. Additionally, powder silica was used to intensify and uniformize the colour of the obtained product. Following optimization, the developed μPAD enabled iodide quantification within the range of 10–100 μM, with a detection limit of 3 μM, and was successfully applied to seaweeds and dietary supplements. The device represents a valuable tool for point-of-care analysis, can be used by untrained personnel at home, and is easily disposable, low-cost, and user-friendly.
- Newly designed microfluidic paper-based device for iodide determination in both food and biological samplesPublication . Pereira, Mafalda G.; Rangel, António O. S. S.; Mesquita, Raquel B. R.
- A novel approach to chloride determination using a lab-on-valve flow systemPublication . Paluch, Justyna; Pereira, Mafalda G.; Mesquita, Raquel B. R.; Rangel, António O. S. S.
- Smart sampling procedure for metal ions assessment in dynamic water systemsPublication . Mesquita, Raquel B. R.; Pereira, Mafalda G.; Rodrigues, Francisco A. P.; Melo, Maria M. P.; Ferreira, Francisca T. S. M.; Ribas, Tânia C. F.; Rangel, António O. S. S.Water bodies are dynamic systems, and the presence of metal ions must be a target of spatial-temporal monitoring. The adverse effects of metal ions are well documented, not only for those which display toxic, carcinogenic, mutagenic and teratogenic effects for living organisms like lead, cadmium, mercury, arsenic and chromium but also for zinc, iron and copper, if present in high concentrations. In aquatic systems, they can be present in different forms, namely by the chelation of their metal ions with inorganic or organic ligands, making their toxicity dependent on the respective form. The real-time monitoring is rather cumbersome as current methods rely on transport to off-site laboratories, disrupting the sample characteristics due to pH and redox potential change and exposure to oxygen, light or temperature shifts, leading to diverse chemical equilibria shifts. In this context, a project, denominated Aqua_Smart, was designed with the main aim of devising an integrated smart sampling and automatic monitoring of toxic metal ions in aquatic systems. The idea is to devise microtubes (cartridges-like tubes) packed with novel sorbents (SPE) to collect the samples. These can be moved to specific sampling points and used in onboard campaigns. The sorbent material can be enriched with analytes by perfusing the sampling device with a large water volume, along with interferents removal; then, the enriched plug is eluted for measurement. The analytical determination is to be based on flow-based techniques with miniaturized optical detection to make the apparatus portable equipment. The whole process, sampling/preparation/measurement, will become automated, enabling the real-time monitoring of various metal species in water bodies. Within the scope of this project, a cartridge packed with a sorbent material for cadmium sampling and enrichment was developed. Additionally, a sequential injection method, using cartridges to discriminate between the different analytes, was also developed for the multiparametric determination of copper, zinc, and manganese determination in water.