# Microfluidic based injection systems for capillary electrophoresis coupled to contactless conductivity, fluorescence and mass spectrometric detection

Furter, Jasmine. Microfluidic based injection systems for capillary electrophoresis coupled to contactless conductivity, fluorescence and mass spectrometric detection. 2022, Doctoral Thesis, University of Basel, Faculty of Science.

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Official URL: https://edoc.unibas.ch/88826/

The last project was the development of an automated capillary electrophoresis instrument for the coupling to a mass spectrometer by using an interface free sheathless nanoelectrospray. The microfluidic part responsible for sample injection contained no electronics to avoid damage of the devices due to the high voltage applied to the injection end. Instead, pneumatic valves and different pressures were used for the injection process. A capillary with an internal diameter of 15 $\mu m$ was employed for obtaining good resolution. Volatile buffers based on acetic acid were used to achieve acceptable separation and ionization of the analytes. The feasibility of the set-up was demonstrated by separating three benzalkonium chloride homologues qualitatively. Good resolution and detection limits were obtained for the quantitative measurements of four pesticides in spiked grape juice.