Benedikt Wimmer (PhD)

For my PhD thesis, I deal with the extraction and quantification of glyphosate in food, environmental and human specimen. The worldwide use of glyphosate as a broadband herbicide has increased drastically during the last four decades. Due to glyphosate’s physicochemical properties – small molecule with three moieties resutling in highly polar and charged species – it adsorbes readily on oxidic surfaces or forms chelates with divalent metal cations. However, these properties also result in difficulties for analysis and often lead to the necessity for derivatization. I developed a derivatization-free and direct CE-MS-method, making use of the strong acidity of glyphosate, capable to quantify the analyte in complex matrices. Besides method optimization, development of extraction prozesses for environmental samples like soils are in focus: in cooperation with the institute for geoscience, a better understanding of the fate of glyphosate in the environment is envisaged. Glyphosate is not only microbiologically degraded; it adsorbs on oxidic minerals, thus remaining in the corresponding layer of earth, but it may leach due to the formation of complexes or the presence of phosphate. To gain a better understanding of the mobility and bioavailability of glyphosate, influencing factors like soil pH, cation exchange capacity, or soil composition, are examined.

The project is part of the Collaborative Research Center CAMPOS and financed by the German Research Foundation.

Teaching:

Master Lecture „Electromigration Separation Techniques“

Practical Course in phyical chemistry for chemists (bachelor)

Cooperation:

Geosciences, Tübingen University

Ecotoxicology, Tübingen University