Novel optical PVC probes for on-site detection/determination of fluoroquinolones in a solid/liquid interface: Application to the determination of Norfloxacin in aquaculture water

A novel optical disposable probe for screening fluoroquinolones in fish farming waters is presented, having Norfloxacin (NFX) as target compound. The colorimetric reaction takes place in the solid/liquid interface consisting of a plasticized PVC layer carrying the colorimetric reagent and the sample solution. NFX solutions dropped on top of this solid-sensory surface provided a colour change from light yellow to dark orange. Several metals were tested as colorimetric reagents and Fe(III) was selected. The main parameters affecting the obtained colour were assessed and optimised in both liquid and solid phases. The corresponding studies were conducted by visible spectrophotometry and digital image acquisition. The three coordinates of the HSL model system of the collected image (Hue, Saturation and Lightness) were obtained by simple image management (enabled in any computer). The analytical response of the optimised solid-state optical probe against concentration was tested for several mathematical transformations of the colour coordinates. Linear behaviour was observed for logarithm NFX concentration against Hue+Lightness. Under this condition, the sensor exhibited a limit of detection below 50 μM (corresponding to about 16 mg/mL). Visual inspection also enabled semi-quantitative information. The selectivity was ensured against drugs from other chemical groups than fluoroquinolones. Finally, similar procedure was used to prepare an array of sensors for NFX, consisting on different metal species. Cu(II), Mn(II) and aluminon were selected for this purpose. The sensor array was used to detect NFX in aquaculture water, without any prior sample manipulation.

Camões - Instituto da Cooperação e da Língua Portuguesa [Camões, IP] português língua de herança [PLH] - língua e identidade

Neste artigo, abordamos, num primeiro momento, a relação entre língua e identidade, tendo em mente que um dos objetivos principais do EPE [Ensino Português no Estrangeiro] é reforçar o vínculo afetivo dos alunos com as suas raízes. O trabalho que aqui apresentamos visa, precisamente, contribuir para a valorização desse elo afetivo dos alunos do EPE na Alemanha, com a LP [Língua Portuguesa] e com uma parte integrante da sua identidade. Num segundo momento, tendo em conta a heterogeneidade dos nossos alunos, dos seus perfis linguísticos e culturais, identificamos que estatuto assume a LP para estes alunos, elucidando sobre as dimensões pedagógicas adotadas ou a adotar no processo de E/A [Ensino e aprendizagem] do EPE. Destacamos, assim, o conceito de Português Língua de Herança [PLH], estatuto que o português assume para os alunos do EPE na Alemanha, percecionado como a língua minoritária, usada pelos filhos dos emigrantes das segundas e terceiras gerações, em contexto restrito, no seio familiar, com a família e, de uma forma menos frequente, com os amigos portugueses.