Pulsed electron beams in ion mobility spectrometry

Abstract

Abstract:Ion mobility spectrometry is a well-known technique used to analyze trace gases in ambient air. Typically, it works by employing a radioactive source to provide electrons with high energy to ionize the analytes in a series of chemical reactions. During the past ten years non-radioactive sources have been one of the subjects of interest in ion mobility spectrometry, initially in order to replace radioactive sources as a result of general security and regulatory concerns. Among these non-radioactive sources especially pulsed sources have recently been shown to additionally improve the analytic information provided by ion mobility spectrometers. In this review we will describe the progress regarding the application of pulsed non-radioactive electron sources in ion mobility spectrometry and show the recent analytical advances that have been achieved by using pulsed electron beams.

Acetone and perdeuterated acetone in UV-IMS

“…The separation of ions in drift time ion mobility spectrometers (IMS) is based on the collision of the ions with neutral drift gas under the influence of an electric field [1]. Since IMS are often operated at ambient pressure (without the need of bulky vacuum pumps), and have extremely low limits of detection (low ppbV and even pptV in less than a second) when operated with atmospheric pressure chemical ionization (APCI) sources [2][3][4][5], they are widely used in several applications. Besides the academic value of ultra-high resolution IMS, e.g.…”

Detection of Organic Pollutants with a Pulsed Ion Mobility Spectrometer

“…The lower spectrum shows the decay behavior when introducing a delay time between ion production and detection. In the positve mode the RIP decays fastest, the monomer peaks decay more slowly than the RIP but faster than dimer peaks [7]. So again the peak at ca.…”

“…These are formed by using free electrons that react with air molecules, especially nitrogene. The results are H 3 O + clusters and O 2 -clusters. These react with the analyte molecules, and depending on their chemical and physical properties, either positvely charged analyte ions are formed (by e.g.…”

“…it is 30 ppmv) only the corresponding monomer peak appears. The IMS spectrum of two substances thus can show is the worst case six peaks: One for the reactant ions, one for each monomer, one for each dimer, and one for the asymmetric dimer [3]. For three substances it would be accordingly ten peaks.…”

Atmospheric pressure chemical ionization of explosives induced by soft X-radiation in ion mobility spectrometry: mass spectrometric investigation of the ionization reactions of drift gasses, dopants and alkyl nitrates

“…no external power supply required) in the construction of handheld spectrometers, there are efforts to replace radioactive sources for technical (ion formation is not suppressible) as well as regulatory (safety and disposal concerns) reasons. Alternative ionization methods currently in development or already commercially available include VUV photoionization, corona discharge ionization, secondary electrospray ionization and ionization by soft X‐radiation or electron beam sources …”