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Reis Duarte, Kátia

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  • Carbon nanotube field effect transistor biosensor for the detection of toxins in seawater
    Publication . Marques, Inês; Costa, João Pinto da; Justino, Celine; Santos, Patrícia; Duarte, Kátia; Freitas, Ana; Cardoso, Susana; Duarte, Armando; Rocha-Santos, Teresa
    Disposable field effect transistors (FET) biosensors (bio-FET) based on carbon nanotubes were fabricated for detection of domoic acid (DA), which belongs to the group of biotoxins associated with the amnesic shellfish poisoning. The analytical results obtained with the bio-FET were compared with those obtained with a traditional methodology (enzyme-linked immunosorbent assay) in order to validate the bio-FET for DA detection. Standard solutions of DA with concentrations between 10 and 500 ng L−1 were tested in order to construct the calibration curve, where five bio-FET were used for reproducibility estimation and two analytical measurements were performed for each bio-FET for repeatability estimation. Ten spiked artificial seawater samples were used to validate the bio-FET. The obtained reproducibility (0.52–1.43%), repeatability (0.57–1.27%), limit of detection (10 ng L−1) and recovery range (92.3–100.3%) reveal an adequate analytical performance of the bio-FET for the detection of DA in environmental samples such as seawater samples.
  • Disposable sensors for environmental monitoring of lead, cadmium and mercury
    Publication . Duarte, Katia; Justino, Celine I. L.; Freitas, Ana C.; Gomes, Ana M. P.; Duarte, Armando; Rocha-Santos, Teresa A. P.
    Miniaturization is an increasing trend in the field of analytical chemistry as a response to the need to develop new analytical techniques for food, clinical, and environmental applications. There is therefore also an increasing trend towards the use of miniaturized disposable sensors, which are inexpensive and designed to be one-shot and do not require pre-treatment prior to use or cleaning between measurements. This review describes disposable sensors for detection of lead, cadmium and mercury in the environment, taking into account their analytical performance. Further, we also discuss the role of certain factors, such as the immobilization procedure and surface modification affecting the analytical characteristics of sensors. Finally, we comment on future applications and potential research interest in this field.