Electric field assisted thermal desorption ionization using an infrared laser

A new technique has been developed for the formation of gas-phase electrons and ions by electric field assisted thermal desorption ionization at atmospheric pressure. Experiments were carried out using a sharp tungsten wire tip coated with a thin solid sample film which was irradiated by a 10.6 μm infrared laser. By applying a strong electric field on the laser-irradiated tungsten wire tip, abundant ions such as alkali ions, halide ions, and also multiply charged negative ions S(2)O(6)(2-) and S(2)O(8)(2-), were formed. Copyright 1999 John Wiley & Sons, Ltd.