Monitoring pharmaceuticals in aquatic environment using biomass-based sorbents as sample pre-concentration strategy

• Autor(a) principal: Stratulat, Alexandr
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/34473
• topic: Sulfamethoxazole; Carbamazepine; Solid-phase extraction; Alternative sorbents; Activated carbon; Water contamination

In recent years, the level of pollution of aquatic ecosystems with pharmaceuticals has increased significantly, including carbamazepine (CBZ) and sulfamethoxazole (SMX), which are among the most persistent aquatic pollutants that pose a risk to both humans and environmental biodiversity. In this regard, research aimed at the detection and identification of pharmaceuticals in the environment remains a priority. The low levels at which these contaminants occur together with the complexity of the samples usually imply the need of sample clean-up and preconcentration strategies prior to the quantification methodologies. Solid phase extraction (SPE) is more frequently used due to the possibility of the automatization and the vast diversity of sorbents available. However, its use in large environmental screenings brings a significant increase in the cost of the analytical process, generally associated to the sorbents. The preparation of alternative sorbents from wastes has received growing attention, guided by the circular economy paradigm. In this work, two sorbents, derived from waste materials (spent brewery grains and primary papermill sludge) were produced by chemical activation, followed by conventional pyrolysis, and subsequently physically and chemically characterized (point of zero charge, specific surface area, scanning electron microscopy, proximate and ultimate analyses). These sorbents were used in SPE cartridges and a preconcentration methodology for SMX and CBZ in water samples was developed and high-performance liquid chromatography was used for their determination and quantification. Several parameters of the SPE procedures were optimized, including the type and mass of sorbent in the cartridge for each pharmaceutical, as well as the type and volume of eluent used, contact time during elution and pharmaceuticals sample volume. After the optimization procedure limits of detection achieved for SMX and CBZ were 15 ng/L and 17 μg/L, respectively. When using the developed method for the determination of pharmaceuticals in real water samples, the recovery efficiency in river water was maintained for both pharmaceuticals for a range of concentrations, however for wastewater it decreased significantly. It was concluded that the developed method was accurate, reproductible and suitable to be used for the determination of SMX and CBZ in surface waters, however it should be improved for their determination in effluent water.