Institute of Physical and Theoretical Chemistry

Fluorescence detection in capillaries on microfluidic chips and for solid-state fluorescence

In comparison to photometric detection, fluorescence detection is interesting for the optimization of detection limits in combination with increased selectivity of the detection system for various analytical methods. We mainly use a frequency-quadrupled Nd:YAG-laser due to its emission the UV light range. This enables us to excite and detect native fluorescence of analytes even with relatively small chromophore systems. Additionally, we also use laser and light emitting diodes for analyte excitation in the visible light spectrum. In cooperation with J&M Analytik AG (Essingen) we develop measurement cells for detection which provide good detection limits without a negative impact on analyte resolution due to very small optical volumes. The consequent use of optical fibers gives rise to a high degree of flexibility in our modular setups. Analyte detection is achieved via sensitive photomultipliers. Our setup has been applied for the analysis of harmala alkaloids in many biogenic drugs. Furthermore, fluorescence analysis is used for fluorescently labeled glycans and proteins.

Fluorescence analysis with spatial resolution on microfluidic glass chips is optimized to monitor the movement of the analyte of interest in the interface of multidimensional separation techniques. The channel image is achieved with optical fiber arrays and enable a very precise analyte transfer from one dimension to the other.

Cooperations:

  • J&M Analytik AG, Essingen

Publications:

  1. On-chip intermediate LED-IF-based detection for the control of electromigration in multichannel networks
    D. Sydes, P. A. Kler, H. Meyer, P. Zipfl, D. Lutz, C. Huhn, Anal. Bioanal. Chem. 2016, 408, 8713-8725

  2. Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms
    E. Woltmann, H. Meyer, D. Weigel, H. Pritzke, T. N. Posch, P. A. Kler, K. Schürmann, J. Roscher, C. Huhn, Anal. Bioanal. Chem. 2014, 25, 6347-6362
  3. Alignment of laser-induced fluorescence and mass spectrometric detection traces using electrophoretic mobility scaling in CE-LIF-MS of labeled N-glycans
    C. Huhn, L. R. Ruhaak, J. Mannhardt, M. Wuhrer, C. Neusüß, A. M. Deelder, H. Meyer; Electrophoresis 2012, 33, 563–566
  4. Capillary electrophoresis – laser induced fluorescence – electrospray ionization-mass spectrometry: A case study
    C. Huhn, C. Neusüß, M. Pelzing, U. Pyell, J. Mannhardt, M. Pütz, Special issue on CE-MS, Electrophoresis 2005, 26, 1389–1397
  5. Determination of tryptamine derivatives in illicit synthetic drugs by capillary electrophoresis and UV-laser-induced fluorescence detection
    C. Huhn, M. Pütz, N. Martin, R. Dahlenburg, U. Pyell, Electrophoresis 2005, 26, 2391-2401

Patents:

C. Huhn, H. Meyer, J. Mannhardt, C. Neusüß, utility patent 202008009113.6 Deutsches Patent- und Markenamt