Evaluation of biotoxins in marine ecosystems by new analytical and biological strategies
- Autores: Cristina Bosch Orea
- Directores de la Tesis: Marinella Farré Urgell (dir. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2021
- Idioma: español
- Tribunal Calificador de la Tesis: Encarnación Moyano Morcillo (presid.), Mònica Campàs i Homs (secret.), António Manuel Barros Marques (voc.)
- Programa de doctorado: Programa de Doctorado en Química Analítica y Medio Ambiente por la Universidad de Barcelona
- Materias:
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- Resumen
In this thesis is presented the development of different analytical methodologies for the analysis of marine biotoxins in seawater. The objectives were the development of the methods and the application to study the biotoxins in marine environments as well as to use it as early warning tools able to detect the presence of the biotoxins at low concentrations previous to an algal bloom development.
The analytical development has been carried out evaluating the precision, accuracy, selectivity and sensibility of the methods. Due to the diverse physic-chemical properties between the different groups of toxins, three different methodologies have been created. First step of the methods consisted in a sample pre-treatment to eliminate the possible interferences in the sample that could difficult the instrumental analysis. For this reason, the biotoxins were extracted from seawater and concentrated to achieve better sensibility. Then, the seawater was filtered and the particulate and filtrate portions were separated, treated and analysed separately. The extraction of the biotoxins form the particulate was carried out with methanol and assisted with ultrasounds. For the filtrate portion solid phase extraction was employed at different conditions conditioned by the different groups of biotoxins. The analysis of the extracts was performed by high performance liquid chromatography coupled to high resolution mass spectrometry through the ionization by electrospray. The chromatographic separation was carried out by hydrophilic interaction and reversed phase modes. The acquisition mode for the mass spectrometry was the combination of full scan at high resolution with tandem mass.
After being validated, the three methodologies were applied to study the occurrence of the different biotoxins in the Mediterranean Sea. In the Catalan’s littoral, okadaic acid was found in concentrations ranging from 2 ng/L to 9.5 μg/L. Domoic acid was also present in the study of Ebro delta, reaching the highest concentration of 69.5 ng/L during summer. Also, the most hydrophilic marine toxins were studied in Mar Menor, Murcia, but any of the toxins was detected. Finally, one of the methods was used to validate an immunoassay capable to detect and quantify five pollutants in seawater, being one of them domoic acid.
