Direct coupling of polymer-based microchip electrophoresis to online MALDI-MS using a rotating ball inlet
We report on the coupling of a polymer-based microfluidic chip to a MALDI-TOF MS using a rotating ball interface. The microfluidic chips were fabricated by micromilling a mold insert into a brass plate, which was then used for replicating polymer microparts via hot embossing. Assembly of the chip was accomplished by thermally annealing a cover slip to the embossed substrate to enclose the channels. The linear separation channel was 50 μm wide, 100 μm deep, and possessed an 8 cm effective length separation channel with a double-T injector (Vinj = 10 nL). The exit of the separation channel was machined to allow direct contact deposition of effluent onto a specially constructed rotating ball inlet to the mass spectrometer. Matrix addition was accomplished in-line on the surface of the ball. The coupling utilized the ball as the cathode transfer electrode to transport sample into the vacuum for desorption with a 355 nm Nd:YAG laser and analyzed on a TOF mass spectrometer. The ball was cleaned online after every rotation. The ability to couple poly(methylmethacrylate) microchip electrophoresis devices for the separation of peptides and peptide fragments produced from a protein digest with subsequent online MALDI MS detection was demonstrated. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Publication Source (Journal or Book title)
Musyimi, H., Guy, J., Narcisse, D., Soper, S., & Murray, K. (2005). Direct coupling of polymer-based microchip electrophoresis to online MALDI-MS using a rotating ball inlet. Electrophoresis, 26 (24), 4703-4710. https://doi.org/10.1002/elps.200500317