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Title: Mobility Peak Tailing Reduction in a Differential Mobility Analyzer (DMA) Coupled with a Mass Spectrometer and Several Ionization Sources

Abstract

The differential mobility analyzer (DMA) is a narrow-band linear ion mobility filter operating at atmospheric pressure. It combines in series with a quadrupole mass spectrometer (Q-MS) for mobility/mass analysis, greatly reducing chemical noise in selected ion monitoring. However, the large flow rate of drift gas (~1000 L/min) required by DMAs complicates the achievement of high gas purity. Additionally, the symmetry of the drying counterflow gas at the interface of many commercial MS instruments, is degraded by the lateral motion of the drift gas at the DMA entrance slit. As a result, DMA mobility peaks often exhibit tails due to the attachment of impurity vapors, either (1) to the reagent ion within the separation cell, or (2) to the analyte of interest in the ionization region. In order to greatly increase the noise-suppression capacity of the DMA, we describe various vapor-removal schemes and measure the resulting increase in the tailing ratio, (TR = signal at the peak maximum over signal two half-widths away from this maximum). Here we develop a low-outgassing DMA circuit connected to a mass spectrometer, and test it with three ionization sources (APCI, Desolvating-nano ESI, and Desolvating low flow SESI). While prior TR values were in the range 100–1000,more » the three new sources achieve TR ~ 10{sup 5}. The SESI source has been optimized for maximum sensitivity, delivering an unprecedented gain for TNT of 190 counts/fg, equivalent to an ionization efficiency of one out of 140 neutral molecules. .« less

Authors:
 [1];  [2]
  1. SEADM (Spain)
  2. Yale University, Mechanical Engineering Department (United States)
Publication Date:
OSTI Identifier:
22776908
Resource Type:
Journal Article
Journal Name:
Journal of the American Society for Mass Spectrometry
Additional Journal Information:
Journal Volume: 28; Journal Issue: 8; Other Information: Copyright (c) 2017 American Society for Mass Spectrometry; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-0305
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; FILTERS; IMPURITIES; ION MOBILITY; IONIZATION; MASS SPECTROMETERS; NOISE; QUADRUPOLES; REDUCTION; SENSITIVITY; SPECTROSCOPY; SYMMETRY

Citation Formats

Amo-Gonzalez, Mario, and Fernandez de la Mora, Juan, E-mail: juan.delamora@yale.edu. Mobility Peak Tailing Reduction in a Differential Mobility Analyzer (DMA) Coupled with a Mass Spectrometer and Several Ionization Sources. United States: N. p., 2017. Web. doi:10.1007/S13361-017-1630-2.
Amo-Gonzalez, Mario, & Fernandez de la Mora, Juan, E-mail: juan.delamora@yale.edu. Mobility Peak Tailing Reduction in a Differential Mobility Analyzer (DMA) Coupled with a Mass Spectrometer and Several Ionization Sources. United States. doi:10.1007/S13361-017-1630-2.
Amo-Gonzalez, Mario, and Fernandez de la Mora, Juan, E-mail: juan.delamora@yale.edu. Tue . "Mobility Peak Tailing Reduction in a Differential Mobility Analyzer (DMA) Coupled with a Mass Spectrometer and Several Ionization Sources". United States. doi:10.1007/S13361-017-1630-2.
@article{osti_22776908,
title = {Mobility Peak Tailing Reduction in a Differential Mobility Analyzer (DMA) Coupled with a Mass Spectrometer and Several Ionization Sources},
author = {Amo-Gonzalez, Mario and Fernandez de la Mora, Juan, E-mail: juan.delamora@yale.edu},
abstractNote = {The differential mobility analyzer (DMA) is a narrow-band linear ion mobility filter operating at atmospheric pressure. It combines in series with a quadrupole mass spectrometer (Q-MS) for mobility/mass analysis, greatly reducing chemical noise in selected ion monitoring. However, the large flow rate of drift gas (~1000 L/min) required by DMAs complicates the achievement of high gas purity. Additionally, the symmetry of the drying counterflow gas at the interface of many commercial MS instruments, is degraded by the lateral motion of the drift gas at the DMA entrance slit. As a result, DMA mobility peaks often exhibit tails due to the attachment of impurity vapors, either (1) to the reagent ion within the separation cell, or (2) to the analyte of interest in the ionization region. In order to greatly increase the noise-suppression capacity of the DMA, we describe various vapor-removal schemes and measure the resulting increase in the tailing ratio, (TR = signal at the peak maximum over signal two half-widths away from this maximum). Here we develop a low-outgassing DMA circuit connected to a mass spectrometer, and test it with three ionization sources (APCI, Desolvating-nano ESI, and Desolvating low flow SESI). While prior TR values were in the range 100–1000, the three new sources achieve TR ~ 10{sup 5}. The SESI source has been optimized for maximum sensitivity, delivering an unprecedented gain for TNT of 190 counts/fg, equivalent to an ionization efficiency of one out of 140 neutral molecules. .},
doi = {10.1007/S13361-017-1630-2},
journal = {Journal of the American Society for Mass Spectrometry},
issn = {1044-0305},
number = 8,
volume = 28,
place = {United States},
year = {2017},
month = {8}
}