Interfaces and on-chip detection for two-dimensional coupling of isoelectric focusing with capillary electrophoresis?mass spectrometry.

KLER, PABLO A.; MEYER, HANS; SYDES, DANIEL; HUHN, CAROLIN

Cork

Simposio; 31st International Symposium on Chromatography (ISC2016).; 2016

Content: Multidimensional separation techniques recently gained significant attention. In comparison to chromatography the technical implementation for multidimensional electromigrative separation techniques is less advanced owing to the higher requirements essential for an efficient sample transfer between the two dimensions. Due to the small peak widths, mostly heart-cutting techniques are used today.As an example we here present our technical innovations regarding the coupling of capillary isoelectric focusing with capillary electrophoresis ? mass spectrometry (cIEF/CE-MS). Instead of increasing the peak capacity, the second dimension serves as a cleanup to remove ampholytes impairing the mass spectrometric detection from the proteins of interest.The focus of our study is on the design and optimization of the microfluidic interface connecting up to four capillaries via a common intersection for both dimensions. This common intersection then houses the sample plug at the start of the CE separation. In order to achieve an efficient analyte transfer, the monitoring of the common intersection is highly recommended. We here present the spatially resolved fluorescence monitoring of labeled proteins entering the chip interface using an array of optical fibers. For detection a hyperspectral camera which gives rise to a time dependent and wavelength-resolved image of the common intersection is implemented.First results for cIEF/CE-MS with the hybrid capillary-microchip an on-chip spatially and wavelength-resolved monitoring of the analyte transfer are presented using model proteins.