My work is focused on the human phase-II-metabolism of salbutamol, more precisely the sulfoconjugation by sulfotransferases (SULTs). I am working with genetically modified yeast cells (Schizosaccharomyces pombe), expressing specific SULTS to investigate the activity of these SULTs towards salbutamol and to utilize the cells for biosynthesis of reference material. Additionally, I developed an in vitro assay to investigate drug-drug interactions through the inhibition of SULTs. In the end, the results of my experiments will be further investigated in human excretion studies. As method of analysis, I use LC-MS/MS (mainly LC-QQQ) for which method development, method optimization and method validation is also part of my work.