In the study, the researcher used a very high-resolution mass spectrometer
Organic compounds can impact aquatic systems. Hence the importance of their characterizations from a qualitative and quantitative point of view, with a view to increasing knowledge about the compounds and processes that can impact them both in relation to the generation of carbon dioxide and their influence on the bioavailability of toxic substances.
Chemist Jose Javier Meléndez Pérez, a graduate from the Industrial University of Santander, in Colombia, set himself this task in work supervised by professor Marcos Nogueira Eberlin, from the Department of Analytical Chemistry at the Institute of Chemistry (IQ) at Unicamp. The focus of the researcher's work was the characterization of organic compounds dissolved in water from different types of aquatic systems in the State of São Paulo (estuary, sea, river, lagoon), some with little human impact – Cananéia estuary and continental shelf, nearby Ubatuba – and others most impacted – Monjolinho river, in the municipality of São Carlos and the lagoon of Parque Hermógenes de Freitas Leitão Filho, next to the Unicamp campus.
The entire set of organic compounds dissolved in water in aquatic systems is generically designated by the acronym DOM (dissolved organic matter), regardless of their origins or how they form. They can result from human activities, such as detergents, pharmaceuticals and their degradation products, or have natural origins, such as lignins, which come from plants, or fatty acids, originating from plants and animals.
The various constituents of dissolved organic matter can undergo numerous transformation processes interacting with biota - a set of animal and plant beings in a region, with sediment constituents and undergo degradation, among many other interactions, which can lead to changes in biogeochemical systems. Thus, for example, the occurrence of a factor that led to a drastic increase in the degradation of organic matter would lead to the formation of carbon dioxide, one of the main causes of the greenhouse effect and global warming. Therefore, the DOM is an important component of the global carbon cycle and small changes in its size and behavioral dynamics can potentially impact many of Earth's biogeochemical systems, with consequences for global warming and aquatic life.
Research
Hence the importance of characterizing DOM from a qualitative and quantitative point of view, with a view to increasing knowledge about the compounds and processes that can impact aquatic systems, both in relation to the generation of carbon dioxide and its influence on the bioavailability of substances. toxic.
The researcher explains that he used a very high resolution mass spectrometer in the study and explains: “DOM is a very complex mixture and no analytical technique would allow us to fully understand its composition. However, very high resolution mass spectrometry makes it possible to simultaneously detect and identify a wide range of these constituents, work preceded and complemented by other techniques such as gas and liquid chromatography”.
This set of analyzes made it possible to identify substances of natural origin in aquatic organic compounds, such as fatty acids, lignin derivatives and organic sulfur components, as well as compounds of anthropogenic origin, such as detergents and their degradation products. The experiments revealed that DOM constituents sequester sulfides from aquatic environments, reducing the bioavailability of these substances, preventing them from exerting their cytotoxic activities in biota.
The study also showed that one of the main types of compounds found in DOM, mainly in non-impact environments, are lignin derivatives that can be used as raw materials to obtain products of commercial interest such as bio-oils or solvents. chemicals.
