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Fabrication of enclosed SU‐8 tips for electrospray ionization‐mass spectrometry
Author(s) -
Tuomikoski Santeri,
Sikanen Tiina,
Ketola Raimo A.,
Kostiainen Risto,
Kotiaho Tapio,
Franssila Sami
Publication year - 2005
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500475
Subject(s) - fabrication , electrospray , fluidics , mass spectrometry , materials science , electrospray ionization , analytical chemistry (journal) , nanotechnology , chromatography , chemistry , electrical engineering , engineering , medicine , alternative medicine , pathology
We describe a novel electrospray tip design for MS which is fabricated completely out of SU‐8 photoepoxy. A three‐layer SU‐8 fabrication process provides fully enclosed channels and tips. The tip shape and alignment of all SU‐8 layers is done lithographically and is therefore very accurate. Fabrication process enables easy integration of additional fluidic functions on the same chip. Separation channels can be made with exactly the same process. Fluidic inlets are made in SU‐8 during the fabrication process and no drilling or other postprocessing is needed. Channels have been fabricated and tested in the size range of 10 μm×10 μm–50 μm×200 μm. Mass spectrometric performance of the tips has been demonstrated with both pressure‐driven flow and EOF. SU‐8 microtips have been shown to produce stable electrospray with EOF in a timescale of tens of minutes. With pressure driven flow stable spray is maintained for hours. Taylor cone was shown to be small in volume and well defined even with the largest channel cross section. The spray was also shown to be well directed with our tip design.