エレクトロスプレー帯電液滴衝撃二次イオン質量分析法

抄録

A new ionization method, electrospray droplet impact ionization (EDI), has been developed for matrix-free secondary-ion mass spectrometry (SIMS). The charged droplets formed by electrospraying 1 M acetic acid aqueous solution are sampled through an orifice with a diameter of 400 μm into the first vacuum chamber, transported into a quadrupole ion guide, and accelerated at 10 kV after exiting the ion guide. The droplets impact on a dry solid sample (no matrix used) deposited on a stainless steel substrate. The secondary ions formed by the impact are transported to a second quadrupole ion guide and are mass-analyzed by an orthogonal time-of-flight mass spectrometer. EDI/SIMS was found to be an easy to operate and versatile method for molecular-level surface analysis.