Miniature Microplasma Discharge-Desorption Atmospheric Pressure Photo-ionization (MD-DAPPI) Source for Ambient Mass Spectrometry.

摘要

As an alternative ionization technique to atmospheric pressure CI and APPI, microplasma-based photoionization has been successfully implemented. The effectiveness of the photo-ionization process is highly dependent on the sampling position and the H_(2) concentration in the discharge gas. The sensitivity of our experiment to changes in the H_(2) concentration is consistent with the theory of VUV production in the Ne_(2)~(*)/H_(2) excimer reaction, though the most effective concentrations were 0.02percent lower than those found in the literature. VUV photons, each having energy sufficient to ionize the PAHs, should be an effective soft ionization approach for many other molecules.