Pulsed-ionization miniature ion mobility spectrometer

We have demonstrated a miniature ion mobility spectrometer (IMS) that employs single pulses of corona discharge ionization. IMS spectra of both positive and negative ions generated from ambient air were measured as a function of drift field under various ionization conditions. Ion mobility spectra were studied with various pulse widths for both positive and negative ions, giving insights into mechanisms and kinetics of corona discharge ionization used in the miniature IMS. A combination of a pulsed potential with a steady do bias was used to generate ions in the miniature IMS. There was a threshold do potential for ion generation for a given pulse height. The do ionization threshold was found to decrease linearly with increasing pulse height.