Polymer Microspray with an Integrated Thick-Film Microelectrode

• Published in: Analytical chemistry (Washington) Vol. 73; no. 22; pp. 5353 - 5357
• Main Authors: Rohner, Tatiana C, Rossier, Joël S, Girault, Hubert H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.11.2001
• Subjects: Ablation; Chemistry; Conductive materials; Electrodes; Exact sciences and technology; Hydrophobicity; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Ionization; Mass spectrometers and related techniques; Mass spectrometry; Microelectrodes - standards; Physics; Polymers; Polymers - chemistry; Proteins; Proteins - chemistry; Reserpine - chemistry; Spectrometry, Mass, Electrospray Ionization - instrumentation; Spectrometry, Mass, Electrospray Ionization - standards; Spectrum analysis; Surface Properties; Thick films; Performance evaluation; Equipment specifications; Thick film devices; Microelectrodes; Performance characteristic; Fluidic devices; Equipment interfaces; Mass spectroscopy; Instrument for chemical analysis; Laser ablation technique; Microminiaturization; Electrospray
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac015557r

A microfabrication process leading to a sheathless electrospray interface for mass spectrometry analysis is described. Photoablation is performed on a polymer substrate, allowing the integration of a thick-film conductive track in a sealed microchannel. High voltage is supplied close to the outlet, through an embedded microelectrode. The microspray is generated directly from the edge of the substrate without any tip addition. The flexibility of this technology provides a wide range of dimensions for the probe and the microelectrode design, including location, shape, and conductive material used. Thanks to the thick-film microelectrode and the hydrophobicity of the polymer, which avoids solution spreading at the outlet, the device has been found to be an efficient ionization source providing a stable MS signal through time. Moreover, the same device can be used several times without failure. The performance of the microspray has been studied in simple infusion mode for proteins and reserpine MS analyses. The detection limit of reserpine was found to be at the picomolar level in full-scan MS mode. It implies also that ∼500 zmol was read consumed during 3 min of infusion. A dynamic range from pico- to millimolar level is also underlined.