Instrumental development and application of multidimensional electromigrative separation techniques: coupling of isotachophoresis with capillary electrophoresis-mass spectrometry

• Applicants: Professorin Dr. Carolin Huhn; Professor Dr.-Ing. Peter Zipfl
• Subject Area: Analytical Chemistry
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 507290570

Chromatographic techniques coupled to mass spectrometry are well established in environmental analysis for analytes of medium to low polarity. For analytes of high polarity and especially contaminants with very low pKa or high pKb values, however, further analytical developments are necessary. Examples are the herbicide glyphosate and the antidiabetic metformin, both with very high anthropogenic input. In this project, capillary electrophoresis-mass spectrometry will be applied for this class of substances. Currently, the detection limits reached are insufficient for environmental analysis due to the low loadability. This analytical task is met in this project by establishing an extensive instrumental solution: Two-dimensional coupling of isotachophoresis and capillary electrophoresis-mass spectrometry enables the simultaneous preconcentration of environmental micropollutants and matrix removal when analyzing surface water samples. In contrast to chromatographic couplings, multidimensional electromigration techniques are not well established due to the higher requirements given by the small volumes at very high separation efficiencies. Currently, no suitable interfaces are commercially available, which also allow intermediate detection. In this project, we will use a microfluidic glass chip from previous studies, which channel layout allows to transfer an analyte only be switching electrical potentials. In order to enable its broad applicability, the control of the potential differences in main and side channels is necessary. We will reach this with a new potential measuring strategy and close-loop control. In addition to instrumental aspects, analytical basics of the analyte transfer between the two separation dimensions, that is, the transition from isotachophoresis to capillary electrophoresis is studied in dependence of instrumental and experimental parameters. We here combine electronic and analytical expertise for instrumental development and analytical-methodological basic research to fully understand and control all aspects of this coupling.

• DFG Programme: Research Grants
• International Connection: Argentina
• Cooperation Partner: Professor Dr.-Ing. Pablo Alejandro Kler, Ph.D.