Hybrid capillary-microchip setup for 2D-electrophoresis coupled to mass spectrometry

KLER, PABLO A.; LUTZ, D.; ZIPFL, P.; MONIAK, A.; HUHN, CAROLIN

Congreso; 20th INTERNATIONAL SYMPOSIUM ON ELECTRO- AND LIQUID PHASE- SEPARATION TECHNIQUES; 2013

Due to the complexity of biological systems, the need of more accurate and efficient analytical tools is continuously growing. Despite the success of liquid chromatography or capillary electrophoresis (CE) coupled to mass spectrometry (MS), many analytical questions remain unsolved due to the large number of analytes in a wide range of concentration, as is the case in proteomics and metabolomics. In order to face these challenges, we develop novel analytical platforms based on electromigrative separation techniques to combine excellent separation performance, on-line pre-concentration and mass spectrometric detection for the analysis of complex biological samples. We here describe a novel hybrid capillary-microchip module for 2D-electrophoretic separations coupling capillary isotachophoresis with capillary electrophoresis (ITP-CE). This instrumental setup combines the versatility of commercial CE equipment with precision and accuracy of microfluidic chips: we use the first for channel filling, injection and electric potential control, and the second for an optimal sample transfer between columns. In order to monitor this sample transfer process we have integrated to the system a contactless capacitively coupled conductivity detector (C4D). The ITP-CE coupling enables us to sequentially perform first ITP for on-line pre-concentration with matrix removal, and second a highly efficient CE separation coupled to mass spectrometric detection for identification and quantification of compounds of biological interest. Different modes of ITP and CE regarding the composition of leading, terminating and background electrolyte are evaluated for comparison with our method. Presented instrumentation and methods are applied to the separation and identification of a mixture of four different human angiotensins in order to demonstrate the analytical capabilities of the developed ITP-C4D-CE-MS system.