The membrane allows materials of interest to enter the detection cell, while attenuating many possible interferents. There the sample is ionized by a weak plasma formed by a nickel 63 radioactive source. A patented dopant material is added to the flow to enhance the ionization process and increase specificity. The ionized sample molecules drift through the cell under the influence of an electric field. An electronic shutter grid allows periodic introduction of the ions into a drift tube where they separate based on charge, mass, and shape.
Smaller ions move faster than larger ions through the drift tube and arrive at the detector.
The amplified current from the detector is measured as a function of time and a spectrum is generated. A microprocessor evaluates the spectrum for the target compound, and determines the concentration based on the peak height. See Figure 1. Copyright 2000 Molecular Analytics. All rights reserved.