Poly(dimethylsiloxane) microchip: microchannel with integrated open electrospray tip.
A polymer microchip with an open tip for electrospray mass spectrometry is presented. The tip consists of a groove with parallel walls where a droplet can form at the end surface. A lid covers the whole chip except at the microchannel tip, which is left open. Poly(dimethylsiloxane) (PDMS) microchips were cast using a nickel mould which in turn was replicated from a dry etched silicon wafer. Tips with microchannel widths of around 50 microm could easily be replicated. Since the tip had no cover, the assembly of microchip and cover was simplified. A total ion current variation of 5% during 300 s was achieved for a 1 microM myoglobin solution. The non-complex design of the cover makes it suitable for versatile tests of chip prototypes. The nickel mould was found to be useful for PDMS microstructure fabrication. Also, such a robust mould allows casting electrospray tips in more rigid thermoset materials.
The Angström Laboratory, Division of Materials Science, Uppsala University, P.O. Box 534, SE-751 21 Uppsala, Sweden.
Malin
M
Svedberg
Monica
M
Veszelei
Jan
J
Axelsson
Mattias
M
Vangbo
Fredrik
F
Nikolajeff
D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D044085:Microfluidics / Q000295:instrumentation; D009532:Nickel / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation*
D004129:Dimethylpolysiloxanes; D011108:Polymers; D009532:Nickel