Surface ionization ion mobility spectrometry

A surface ionization (SI) source was designed and constructed for ion mobil ity spectrometry (IMS). Compared with a conventional Ni-63 source, the surf ace ionization source is as simple and reliable, has an extended dynamic re sponse range, is more selective in response, and does not have regulatory p roblems associated with radioactive ionization sources. The performance of this SI-IMS was evaluated with several different classes df compounds. Trie thylamine was employed for studying the behavior of the ionization source u nder different source conditions and gaseous environments. Amines, tobacco alkaloids, and triazine herbicides were also investigated. Picogram level d etection limits were achieved for target compounds with a response dynamic range of 5 orders of magnitude. Selective monitoring by IMS was also demons trated. While the surface ionization source does not have the universality of response that is obtained with a Ni-63 ionization source, it is an excel lent nonradioactive alternative for the ionization and ion mobility detecti on of those compounds to which it responds.