From August 1 to October 31, I spent my doctoral internship at the Chemistry Department of Umea University in Sweden and participated in two projects. In a project focused on pharmaceuticals effect, I participated perch catching, subsequent tissue sampling, and brain samples processing. The second project's collaboration consisted of creating a system and database of samples taken, quantifying data, and preparing new samples for analysis. This cooperation will continue even after my return. The internship was supported by an Erasmus+ grant.