A novel nib-like design for microfabricated nanospray tips.
We present here novel tips for nanoelectrosray ionization-mass spectrometry (ESI-MS) applications. These ionization sources have a planar geometry in the shape of a nib. Their functioning is based on a principle much akin to that of a fountain pen in that fluids are actuated by capillarity. Once a voltage is applied, an electrospray is formed at the nib tip. The nib fabrication relies on micromachining techniques using the epoxy-based negative photoresist SU-8 and a double exposure photolithographic process. Two types of nib-like sources were fabricated; they were made either conductive by metallization with a nickel layer or non-conductive but hydrophilic by covering them with a SiO(2) layer. In the latter case, the HV was applied via a Pt wire inserted into the reservoir feature of the nib. The nib-like sources were tested on an ion trap mass spectrometer using Gramicidin S samples at concentrations as low as 1 microM and ionization voltages as low as 1.2 kV. We have observed a good overall stability of the spray during the tests with no marked decrease in the signal intensity even under extreme conditions.
Laboratoire de Chimie Organique et Macromoléculaire, UMR CNRS 8009, Université des Sciences et Technologies de Lille Cité Scientifique, Villeneuve d'Ascq, France.
Séverine
S
Le Gac
Cécile
C
Cren-Olivé
Christian
C
Rolando
Steve
S
Arscott