Premium
A planar microfabricated nanoelectrospray emitter tip based on a capillary slot
Author(s) -
Le Gac Séverine,
Arscott Steve,
Rolando Christian
Publication year - 2003
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.200305664
Subject(s) - wafer , capillary action , common emitter , planar , silicon , chemistry , fabrication , mass spectrometry , photoresist , electrospray , optoelectronics , substrate (aquarium) , analytical chemistry (journal) , materials science , nanotechnology , chromatography , composite material , medicine , computer graphics (images) , alternative medicine , oceanography , pathology , layer (electronics) , geology , computer science
We report on the fabrication and testing of planar nib‐like structures for nanoelectrospray ionization‐mass spectrometry (nanoESI‐MS) applications. The micro‐nib structures were fabricated on silicon substrates using the negative photoresist SU‐8; they include capillary slots with widths of 8 and 16 μm. A suitable wafer cleaving step made the nib‐like structures overhang the edge of a silicon substrate to provide a robust interface for nanoESI‐MS applications; this freeing of the nib tip from the wafer surface created a point‐like structure that is essential to establish an electrospray. The micro‐nib sources were successfully tested on an LCQ Deca XP+ ion trap mass spectrometer using peptide samples at concentrations down to 1 μ M . The high voltage was applied using a platinum wire inserted in the sample reservoir upstream to the capillary slot. A Taylor cone was clearly seen at the nib tip. The micro‐nibs performed well at voltages as low as 0.8 kV; such performances are state‐of‐the‐art with respect to current micromachined ESI‐MS interfaces and are conditions comparable to those used for standard emitter tips. In addition, we clearly observed the influence of the micro‐nib slot width on the ionization performances: the narrower the slot, the better the performances.