Fabrication of microchip integrated with electrospray emitter on PMMA for electrophoresis-mass spectrometry

摘要

Recently,more and more Electrospray Ionization Mass Spectrometry (ESI-MS) interfaces were fabricated on polymer chip, for its good biological performance, hydrophobic, low price and it is easy to be fabricated. In this paper, we report on the design, fabrication, and testing of a PMMA micro fluidic chip for Electrophoresis-Electrospray Ionization Mass Spectrometry (MCE-ESI-MS). The chip was composed of two layers, both of them were ablated to leave marks using laser machining with low current, and then break apart along the marks to form a sharp corner on the tip. The micro channel on the bottom layer was fabricated by hot embossing using a silicon mould, this process was done in a stereoscopic microscope to ensure the open channel was moulded on the sharp corner. Four reservoirs were drilled on the top layer, bonding the two layers together. The electrophoresis voltage and electrospray voltage was applied with electrode wires in the reservoirs. ESI liquid was 5% ethanol solution, to form stable electrospray, the distance between the emitter tip and counter electrode is 233um at voltage of 2000 volts.