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Dissolved Carbon Dioxide Sensing Platform for Freshwater and Saline Water Applications: Characterization and Validation in Aquaculture Environments

A sensing configuration for the real-time monitoring, detection, and quantification of dissolved carbon dioxide (dCO(2)) was developed for aquaculture and other applications in freshwater and saline water. A chemical sensing membrane, based on a colorimetric indicator, is combined with multimode opt...

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Detalles Bibliográficos
Autores principales: Mendes, J.P., Coelho, L., Kovacs, B., de Almeida, J.M.M.M., Pereira, C.M., Jorge, P.A.S., Borges, M.T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960747/
https://www.ncbi.nlm.nih.gov/pubmed/31847169
http://dx.doi.org/10.3390/s19245513
Descripción
Sumario:A sensing configuration for the real-time monitoring, detection, and quantification of dissolved carbon dioxide (dCO(2)) was developed for aquaculture and other applications in freshwater and saline water. A chemical sensing membrane, based on a colorimetric indicator, is combined with multimode optical fiber and a dual wavelength light-emitting diode (LED) to measure the dCO(2)-induced absorbance changes in a self-referenced ratiometric scheme. The detection and processing were achieved with an embeded solution having a mini spectrometer and microcontroller. For optrode calibration, chemical standard solutions using sodium carbonate in acid media were used. Preliminary results in a laboratory environment showed sensitivity for small added amounts of CO(2) (0.25 mg·L(−1)). Accuracy and response time were not affected by the type of solution, while precision was affected by salinity. Calibration in freshwater showed a limit of detection (LOD) and a limit of quantification (LOQ) of 1.23 and 1.87 mg·L(−1), respectively. Results in saline water (2.5%) showed a LOD and LOQ of 1.05 and 1.16 mg·L(−1), respectively. Generally, performance was improved when moving from fresh to saline water. Studies on the dynamics of dissolved CO(2) in a recirculating shallow raceway system (SRS+RAS) prototype showed higher precision than the tested commercial sensor. The new sensor is a compact and robust device, and unlike other sensors used in aquaculture, stirring is not required for correct and fast detection. Tests performed showed that this new sensor has a fast accurate detection as well as a strong potential for assessing dCO(2) dynamics in aquaculture applications.