Development of Sniffing Atmospheric Pressure Penning Ionization

Abstract

The atmospheric pressure Penning ionization was applied to the analysis of atmospheric-pressure ambient gaseous samples. The metastable rare gas atoms (Rg῏) were produced by a negative-mode corona discharge of reagent rare gas (Rg). The rare gas containing Rg῏ in the discharge cell flowed out into the ion source cell through a nozzle with an inner diameter of 1 mm as a jet stream. The jet stream acts as a gas-jet pump and the pressure of the ion source cell becomes somewhat lower than the atmospheric pressure. The sample gas at ambient atmospheric pressure was sucked into the reduced-pressure ion source cell through the stainless steel tube (10 cm in length, 1 mm in diameter). The sample gases introduced in the ion source cell are ionized by Penning ionization. This technique was found to be applicable to various gaseous samples such as aromatic compounds, oxygen-and nitrogen-containing compounds, etc. However, no ion signal could be detected for aliphatic hydrocarbons. This may be due to the much smaller ionization cross sections for these compounds than N2 and O2 molecules which are introduced into the ion source together with sample gases.

Physical Processes and Real-Time Chemical Measurement of the Insect Olfactory Environment

“…The popular desorption electro-spray ionization (DESI) method works well typically on solid samples. Numerous related techniques have evolved, some of which accommodate gaseous samples, like the direct analysis in real time (DART) method, which uses an excited gas (plasma) to drive the desorption process of solid, liquid, or gas samples (Cody et al 2005;Haefliger and Jeckelmann 2007), or atmospheric pressure Penning ionization (APPeI; Iwana et al 2006), which uses argon or helium (rare gases) activated by a negativemode corona discharge to ionize a pulled gaseous sample before analysis by TOFMS. Laser photoionization of trace gas molecules has been developed mainly along two, parallel paths: resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) and single photon ionization (SPI) TOFMS (Zimmermann 2005).…”