Abstract

Poster Presentations

Day 2, May 16（Tue.）　　Room P (Foyer, Room 1004-1007)

2P-51　　PDF

High-pressure nanoelectrospray ionization of highly conductive solution using micropipette tips and other porous emitters

(Univ. Yamanashi)
^oNozomu Omata, Zhongbao Han, Lee Chuin Chen

Electrospray ionization (ESI) is a soft ionization method widely used in mass spectrometry for high molecular weight and non-volatile molecules such as proteins and macromolecules. Standard ESI operates under atmospheric pressure. In liquids with high surface tension, high voltages are required to establish a stable cone-jet mode. However, due to corona discharges, it is usually difficult to handle highly conductive aqueous solutions. Organic solvents are usually added to lower the surface tension. However, since biomolecules maintain their physiological structure and function only in water, it is important to perform ESI directly from aqueous solutions in native MS. To handle highly conductive solutions, we performed high-pressure ESI at an operating pressure higher than atmospheric pressure (≈0.5 MPa) to ionize analytes directly from solvents with conductivities of 1 S/m or higher. The high-pressure operation also enabled nanoESI at very low flow rates from a micropipette tip with a large inner diameter. Several emitter designs are evaluated here. One uses a special micropipette tip (Zip Tip C-18) filled with chromatographic particles. We also investigated the possibility of performing high-pressure nanoESI directly from porous emitters such as paper or wooden sticks.