Optical Window on Atmospheric Pressure Ionization Source
Original Publication Date: 1978-Apr-01
Included in the Prior Art Database: 2005-Feb-20
Atmospheric pressure ionization (API) sources have been investigated in recent years as a means to detect trace levels (10/-12/ to 10/-15/ grams) of chemical compounds. When used as the ionization source for a mass spectrometer, the instrument is called an API mass spectrometer. When the source is used to produce ions for a mobility spectrometer, the instrument is referred to as a plasma chromatograph. In both the plasma chromatograph and API mass spectrometer techniques, only ions having a lifetime above a certain minimum are detected. These lifetimes are on the order of milliseconds and longer. In the atmospheric pressure ionization source, a large quantity of electronically excited species (both ionized and neutral molecules and atoms) is produced.