Capillary electrophoresis mass spectrometer

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Scheme of a CE-MS with coupling via ESI source (English)

Capillary electrophoresis-mass spectrometry (CE-MS) provide a coupling method of capillary electrophoresis (Engl. Capillary Electrophoresis , CE) with mass spectrometry (MS) is.

technology

The capillary is on the electrophoresis based analytical separation method . The separation takes place under the influence of an applied electric field in a thin capillary tube in an electrolyte solution . Typical sample volumes are in the range of approx. 10 nanoliters (0.01 mm³), so that only very small amounts of liquid elute from the CE capillary. A combination of capillary electrophoresis with mass spectrometry is therefore technically more complex than that of liquid chromatography with mass spectrometry coupling ; As a result, CE-MS is much less common than HPLC-MS.

Coupling via ESI source

For coupling with an ESI source, the flow into the ion source must usually be increased by means of a "sheath liquid". The coupling can be used in particular in the structure identification and quantitative analysis of polar, organic substances.

Online CE-MALDI-MS

The coupling of capillary electrophoresis with MALDI-TOF (matrix-assisted laser-desorption-ionization with a time of flight mass spectrometer , engl. Time of flight MS) was also technically realized , whereby the MS can be coupled on-line or off-line with the CE. With on-line coupling, the sample is introduced into the MS continuously or as an aerosol . The disadvantage is the need to use volatile buffers, which are limited to special techniques of capillary electrophoresis. An off-line coupling is much easier to implement and enables both processes, electrophoresis and ionization, to be optimized independently of one another.

Individual evidence

  1. ↑ Franz Menzinger: Optimization of a capillary electrophoresis-electrospray-mass spectrometry (CE-ESI-MS) coupling for the structure identification and quantitative analysis of selected polar, organic substances. Dissertation, TU Munich, 2002.
  2. ↑ Kermit K. Murray: Coupling Matrix-assisted Laser Desorption / Ionization to Liquid Separations. In: Mass Spectrometry Reviews 1997, 16, 283-299.
  3. ↑ Sabine Metzger: Mass spectrometric analysis of complex peptide mixtures. Dissertation, Heinrich Heine University Düsseldorf, 2001.