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Sample records for ion mobility separations

  1. Ion Mobility Separation of Peptide Isotopomers

    NASA Astrophysics Data System (ADS)

    Kaszycki, Julia L.; Bowman, Andrew P.; Shvartsburg, Alexandre A.

    2016-05-01

    Differential or field asymmetric waveform ion mobility spectrometry (FAIMS) operating at high electric fields fully resolves isotopic isomers for a peptide with labeled residues. The naturally present isotopes, alone and together with targeted labels, also cause spectral shifts that approximately add for multiple heavy atoms. Separation qualitatively depends on the gas composition. These findings may enable novel strategies in proteomic and metabolomic analyses using stable isotope labeling.

  2. Hybrid ion mobility and mass spectrometry as a separation tool.

    PubMed

    Ewing, Michael A; Glover, Matthew S; Clemmer, David E

    2016-03-25

    Ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) has seen spectacular growth over the last two decades. Increasing IMS sensitivity and capacity with improvements in MS instrumentation have driven this growth. As a result, a diverse new set of techniques for separating ions by their mobility have arisen, each with characteristics that make them favorable for some experiments and some mass spectrometers. Ion mobility techniques can be broken down into dispersive and selective techniques based upon whether they pass through all mobilities for later analysis by mass spectrometry or select ions by mobility or a related characteristic. How ion mobility techniques fit within a more complicated separation including mass spectrometry and other techniques such as liquid chromatography is of fundamental interest to separations scientists. In this review we explore the multitude of ion mobility techniques hybridized to different mass spectrometers, detailing current challenges and opportunities for each ion mobility technique and for what experiments one technique might be chosen over another. The underlying principles of ion mobility separations, including: considerations regarding separation capabilities, ion transmission, signal intensity and sensitivity, and the impact that the separation has upon the ion structure (i.e., the possibility of configurational changes due to ion heating) are discussed.

  3. Ion mobility spectrometer using frequency-domain separation

    DOEpatents

    Martin, S.J.; Butler, M.A.; Frye, G.C.; Schubert, W.K.

    1998-08-04

    An apparatus and method are provided for separating and analyzing chemical species in an ion mobility spectrometer using a frequency-domain technique wherein the ions generated from the chemical species are selectively transported through an ion flow channel having a moving electrical potential therein. The moving electrical potential allows the ions to be selected according to ion mobility, with certain of the ions being transported to an ion detector and other of the ions being effectively discriminated against. The apparatus and method have applications for sensitive chemical detection and analysis for monitoring of exhaust gases, hazardous waste sites, industrial processes, aerospace systems, non-proliferation, and treaty verification. The apparatus can be formed as a microelectromechanical device (i.e. a micromachine). 6 figs.

  4. Ion mobility spectrometer using frequency-domain separation

    DOEpatents

    Martin, Stephen J.; Butler, Michael A.; Frye, Gregory C.; Schubert, W. Kent

    1998-01-01

    An apparatus and method is provided for separating and analyzing chemical species in an ion mobility spectrometer using a frequency-domain technique wherein the ions generated from the chemical species are selectively transported through an ion flow channel having a moving electrical potential therein. The moving electrical potential allows the ions to be selected according to ion mobility, with certain of the ions being transported to an ion detector and other of the ions being effectively discriminated against. The apparatus and method have applications for sensitive chemical detection and analysis for monitoring of exhaust gases, hazardous waste sites, industrial processes, aerospace systems, non-proliferation, and treaty verification. The apparatus can be formed as a microelectromechanical device (i.e. a micromachine).

  5. Method for enhancing the resolving power of ion mobility separations over a limited mobility range

    DOEpatents

    Shvartsburg, Alexandre A; Tang, Keqi; Smith, Richard D

    2014-09-23

    A method for raising the resolving power, specificity, and peak capacity of conventional ion mobility spectrometry is disclosed. Ions are separated in a dynamic electric field comprising an oscillatory field wave and opposing static field, or at least two counter propagating waves with different parameters (amplitude, profile, frequency, or speed). As the functional dependencies of mean drift velocity on the ion mobility in a wave and static field or in unequal waves differ, only single species is equilibrated while others drift in either direction and are mobility-separated. An ion mobility spectrum over a limited range is then acquired by measuring ion drift times through a fixed distance inside the gas-filled enclosure. The resolving power in the vicinity of equilibrium mobility substantially exceeds that for known traveling-wave or drift-tube IMS separations, with spectra over wider ranges obtainable by stitching multiple segments. The approach also enables low-cutoff, high-cutoff, and bandpass ion mobility filters.

  6. Separation of Variant Methylated Histone Tails by Differential Ion Mobility

    SciTech Connect

    Shvartsburg, Alexandre A.; Zheng, Yupeng; Smith, Richard D.; Kelleher, Neil

    2012-07-18

    Differential ion mobility spectrometry (FAIMS) is emerging as a broadly useful tool for separation of isomeric modified peptides with post-translational modifications (PTMs) attached to alternative residues. Such separations were anticipated to become more challenging for smaller PTMs and longer peptides. Here we show that FAIMS can fully resolve localization variants involving a PTM as minuscule as methylation, even for larger peptides in the middle-down range.

  7. Blind Source Separation For Ion Mobility Spectra

    SciTech Connect

    Marco, S.; Pomareda, V.

    2009-05-23

    Miniaturization is a powerful trend for smart chemical instrumentation in a diversity of applications. It is know that miniaturization in IMS leads to a degradation of the system characteristics. For the present work, we are interested in signal processing solutions to mitigate limitations introduced by limited drift tube length that basically involve a loss of chemical selectivity. While blind source separation techniques (BSS) are popular in other domains, their application for smart chemical instrumentation is limited. However, in some conditions, basically linearity, BSS may fully recover the concentration time evolution and the pure spectra with few underlying hypothesis. This is extremely helpful in conditions where non-expected chemical interferents may appear, or unwanted perturbations may pollute the spectra. SIMPLISMA has been advocated by Harrington et al. in several papers. However, more modern methods of BSS for bilinear decomposition with the restriction of positiveness have appeared in the last decade. In order to explore and compare the performances of those methods a series of experiments were performed.

  8. Accelerated High-Resolution Differential Ion Mobility Separations Using Hydrogen

    PubMed Central

    Shvartsburg, Alexandre A.; Smith, Richard D.

    2011-01-01

    The resolving power of differential ion mobility spectrometry (FAIMS) was dramatically increased recently by carrier gases comprising up to 75% He or various vapors, enabling many new applications. However, the need for resolution of complex mixtures is virtually open-ended and many topical analyses demand yet finer separations. Also, the resolving power gains are often at the expense of speed, in particular making high-resolution FAIMS incompatible with online liquid-phase separations. Here, we report FAIMS employing hydrogen, specifically in mixtures with N2 containing up to 90% H2. Such compositions raise the mobilities of all ions and thus the resolving power beyond that previously feasible, while avoiding the electrical breakdown inevitable in He-rich mixtures. The increases in resolving power and ensuing peak resolution are especially significant at H2 fractions above ~50%. Higher resolution can be exchanged for acceleration of the analyses by up to ~4 times, at least. For more mobile species such as multiply-charged peptides, this exchange is presently forced by the constraints of existing FAIMS devices, but future designs optimized for H2 should consistently improve resolution for all analytes. PMID:22074292

  9. Accelerated high-resolution differential ion mobility separations using hydrogen.

    PubMed

    Shvartsburg, Alexandre A; Smith, Richard D

    2011-12-01

    The resolving power of differential ion mobility spectrometry (FAIMS) was dramatically increased recently by carrier gases comprising up to 75% He or various vapors, enabling many new applications. However, the need for resolution of complex mixtures is virtually open-ended and many topical analyses demand yet finer separations. Also, the resolving power gains are often at the expense of speed, in particular making high-resolution FAIMS poorly compatible with online liquid-phase separations. Here, we report FAIMS employing hydrogen, specifically in mixtures with N(2) containing up to 90% H(2). Such compositions raise the mobilities of all ions and thus the resolving power beyond that previously feasible, while avoiding the electrical breakdown inevitable in He-rich mixtures. The increases in resolving power and ensuing peak resolution are especially significant at H(2) fractions above ~50%. Higher resolution can be exchanged for acceleration of the analyses by up to ~4 times. For more mobile species such as multiply charged peptides, this exchange is presently forced by the constraints of existing FAIMS devices, but future designs optimized for H(2) should consistently improve resolution for all analytes.

  10. Characterization of Traveling Wave Ion Mobility Separations in Structures for Lossless Ion Manipulations

    DOE PAGESBeta

    Hamid, Ahmed M.; Ibrahim, Yehia M.; Garimella, Venkata BS; Webb, Ian K.; Deng, Liulin; Chen, Tsung-Chi; Anderson, Gordon A.; Prost, Spencer A.; Norheim, Randolph V.; Tolmachev, Aleksey V.; et al

    2015-10-28

    We report on the development and characterization of a new traveling wave-based Structure for Lossless Ion Manipulations (TW-SLIM) for ion mobility separations (IMS). The TW-SLIM module uses parallel arrays of rf electrodes on two closely spaced surfaces for ion confinement, where the rf electrodes are separated by arrays of short electrodes, and using these TWs can be created to drive ion motion. In this initial work, TWs are created by the dynamic application of dc potentials. The capabilities of the TW-SLIM module for efficient ion confinement, lossless ion transport, and ion mobility separations at different rf and TW parameters aremore » reported. The TW-SLIM module is shown to transmit a wide mass range of ions (m/z 200–2500) utilizing a confining rf waveform (~1 MHz and ~300 Vp-p) and low TW amplitudes (<20 V). Additionally, the short TW-SLIM module achieved resolutions comparable to existing commercially available low pressure IMS platforms and an ion mobility peak capacity of ~32 for TW speeds of <210 m/s. TW-SLIM performance was characterized over a wide range of rf and TW parameters and demonstrated robust performance. In conclusion, the combined attributes of the flexible design and low voltage requirements for the TW-SLIM module provide a basis for devices capable of much higher resolution and more complex ion manipulations.« less

  11. Characterization of Traveling Wave Ion Mobility Separations in Structures for Lossless Ion Manipulations

    SciTech Connect

    Hamid, Ahmed M.; Ibrahim, Yehia M.; Garimella, Venkata BS; Webb, Ian K.; Deng, Liulin; Chen, Tsung-Chi; Anderson, Gordon A.; Prost, Spencer A.; Norheim, Randolph V.; Tolmachev, Aleksey V.; Smith, Richard D.

    2015-10-28

    We report on the development and characterization of a new traveling wave-based Structure for Lossless Ion Manipulations (TW-SLIM) for ion mobility separations (IMS). The TW-SLIM module uses parallel arrays of rf electrodes on two closely spaced surfaces for ion confinement, where the rf electrodes are separated by arrays of short electrodes, and using these TWs can be created to drive ion motion. In this initial work, TWs are created by the dynamic application of dc potentials. The capabilities of the TW-SLIM module for efficient ion confinement, lossless ion transport, and ion mobility separations at different rf and TW parameters are reported. The TW-SLIM module is shown to transmit a wide mass range of ions (m/z 200–2500) utilizing a confining rf waveform (~1 MHz and ~300 Vp-p) and low TW amplitudes (<20 V). Additionally, the short TW-SLIM module achieved resolutions comparable to existing commercially available low pressure IMS platforms and an ion mobility peak capacity of ~32 for TW speeds of <210 m/s. TW-SLIM performance was characterized over a wide range of rf and TW parameters and demonstrated robust performance. In conclusion, the combined attributes of the flexible design and low voltage requirements for the TW-SLIM module provide a basis for devices capable of much higher resolution and more complex ion manipulations.

  12. Characterization of Traveling Wave Ion Mobility Separations in Structures for Lossless Ion Manipulations.

    PubMed

    Hamid, Ahmed M; Ibrahim, Yehia M; Garimella, Sandilya V B; Webb, Ian K; Deng, Liulin; Chen, Tsung-Chi; Anderson, Gordon A; Prost, Spencer A; Norheim, Randolph V; Tolmachev, Aleksey V; Smith, Richard D

    2015-11-17

    We report on the development and characterization of a traveling wave (TW)-based Structures for Lossless Ion Manipulations (TW-SLIM) module for ion mobility separations (IMS). The TW-SLIM module uses parallel arrays of rf electrodes on two closely spaced surfaces for ion confinement, where the rf electrodes are separated by arrays of short electrodes, and using these TWs can be created to drive ion motion. In this initial work, TWs are created by the dynamic application of dc potentials. The capabilities of the TW-SLIM module for efficient ion confinement, lossless ion transport, and ion mobility separations at different rf and TW parameters are reported. The TW-SLIM module is shown to transmit a wide mass range of ions (m/z 200-2500) utilizing a confining rf waveform (∼1 MHz and ∼300 Vp-p) and low TW amplitudes (<20 V). Additionally, the short TW-SLIM module achieved resolutions comparable to existing commercially available low pressure IMS platforms and an ion mobility peak capacity of ∼32 for TW speeds of <210 m/s. TW-SLIM performance was characterized over a wide range of rf and TW parameters and demonstrated robust performance. The combined attributes of the flexible design and low voltage requirements for the TW-SLIM module provide a basis for devices capable of much higher resolution and more complex ion manipulations. PMID:26510005

  13. Multidimensional Separation of Natural Products Using Liquid Chromatography Coupled to Hadamard Transform Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Wenjie; Zhang, Xing; Knochenmuss, Richard; Siems, William F.; Hill, Herbert H.

    2016-05-01

    A high performance liquid chromatograph (HPLC)was interfaced to an atmospheric drift tube ion mobility time of flight mass spectrometry. The power of multidimensional separation was demonstrated using chili pepper extracts. The ambient pressure drift tube ion mobility provided high resolving powers up to 166 for the HPLC eluent. With implementation of Hadamard transform (HT), the duty cycle for the ion mobility drift tube was increased from less than 1% to 50%, and the ion transmission efficiency was improved by over 200 times compared with pulsed mode, improving signal to noise ratio 10 times. HT ion mobility and TOF mass spectrometry provide an additional dimension of separation for complex samples without increasing the analysis time compared with conventional HPLC.

  14. Multidimensional Separation of Natural Products Using Liquid Chromatography Coupled to Hadamard Transform Ion Mobility Mass Spectrometry.

    PubMed

    Liu, Wenjie; Zhang, Xing; Knochenmuss, Richard; Siems, William F; Hill, Herbert H

    2016-05-01

    A high performance liquid chromatograph (HPLC)was interfaced to an atmospheric drift tube ion mobility time of flight mass spectrometry. The power of multidimensional separation was demonstrated using chili pepper extracts. The ambient pressure drift tube ion mobility provided high resolving powers up to 166 for the HPLC eluent. With implementation of Hadamard transform (HT), the duty cycle for the ion mobility drift tube was increased from less than 1% to 50%, and the ion transmission efficiency was improved by over 200 times compared with pulsed mode, improving signal to noise ratio 10 times. HT ion mobility and TOF mass spectrometry provide an additional dimension of separation for complex samples without increasing the analysis time compared with conventional HPLC. Graphical Abstract ᅟ. PMID:26914233

  15. Multidimensional Separation of Natural Products Using Liquid Chromatography Coupled to Hadamard Transform Ion Mobility Mass Spectrometry.

    PubMed

    Liu, Wenjie; Zhang, Xing; Knochenmuss, Richard; Siems, William F; Hill, Herbert H

    2016-05-01

    A high performance liquid chromatograph (HPLC)was interfaced to an atmospheric drift tube ion mobility time of flight mass spectrometry. The power of multidimensional separation was demonstrated using chili pepper extracts. The ambient pressure drift tube ion mobility provided high resolving powers up to 166 for the HPLC eluent. With implementation of Hadamard transform (HT), the duty cycle for the ion mobility drift tube was increased from less than 1% to 50%, and the ion transmission efficiency was improved by over 200 times compared with pulsed mode, improving signal to noise ratio 10 times. HT ion mobility and TOF mass spectrometry provide an additional dimension of separation for complex samples without increasing the analysis time compared with conventional HPLC. Graphical Abstract ᅟ.

  16. Separation of a Set of Peptide Sequence Isomers Using Differential Ion Mobility Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.; Creese, Andrew J.; Smith, Richard D.; Cooper, Helen J.

    2011-08-15

    Protein identification in bottom-up proteomics requires disentangling isomers of proteolytic peptides, a major class of which are sequence inversions. Separation of sequence isomers using ion mobility spectrometry (IMS) has been reported, but limited to pairs of species. Here we demonstrate baseline separation of all seven sequences for a tryptic peptide with eight residues using differential IMS or FAIMS. Evaluations of peak capacity of the method indicate that even larger libraries should generally be separated for heavier peptides with higher charge states.

  17. Ion mobility sensor

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2005-08-23

    An ion mobility sensor which can detect both ion and molecules simultaneously. Thus, one can measure the relative arrival times between various ions and molecules. Different ions have different mobility in air, and the ion sensor enables measurement of ion mobility, from which one can identify the various ions and molecules. The ion mobility sensor which utilizes a pair of glow discharge devices may be designed for coupling with an existing gas chromatograph, where various gas molecules are already separated, but numbers of each kind of molecules are relatively small, and in such cases a conventional ion mobility sensor cannot be utilized.

  18. Separation of a set of peptide sequence isomers using differential ion mobility spectrometry.

    PubMed

    Shvartsburg, Alexandre A; Creese, Andrew J; Smith, Richard D; Cooper, Helen J

    2011-09-15

    Protein identification in bottom-up proteomics requires disentangling isomers of proteolytic peptides, a major class of which are sequence inversions. Their separation using ion mobility spectrometry (IMS) has been limited to isomeric pairs. Here we demonstrate baseline separation of all seven 8-mer tryptic peptide isomers using differential IMS. Evaluation of peak capacity implies that even larger libraries should be resolved for heavier peptides with higher charge states.

  19. Enhancing Biological Analyses with Three Dimensional Field Asymmetric Ion Mobility, Low Field Drift Time Ion Mobility and Mass Spectrometry (µFAIMS/IMS-MS) Separations

    SciTech Connect

    Zhang, Xing; Ibrahim, Yehia M.; Chen, Tsung-Chi; Kyle, Jennifer E.; Norheim, Randolph V.; Monroe, Matthew E.; Smith, Richard D.; Baker, Erin Shammel

    2015-06-30

    We report the first evaluation of a platform coupling a high speed field asymmetric ion mobility spectrometry microchip (µFAIMS) with drift tube ion mobility and mass spectrometry (IMS-MS). The µFAIMS/IMS-MS platform was used to analyze biological samples and simultaneously acquire multidimensional information of detected features from the measured FAIMS compensation fields and IMS drift times, while also obtaining accurate ion masses. These separations thereby increase the overall separation power, resulting increased information content, and provide more complete characterization of more complex samples. The separation conditions were optimized for sensitivity and resolving power by the selection of gas compositions and pressures in the FAIMS and IMS separation stages. The resulting performance provided three dimensional separations, benefitting both broad complex mixture studies and targeted analyses by e.g. improving isomeric separations and allowing detection of species obscured by “chemical noise” and other interfering peaks.

  20. Ion Mobility Separation of Isomeric Phosphopeptides from a Protein with Variant Modification of Adjacent Residues

    SciTech Connect

    Shvartsburg, Alexandre A.; Singer, David; Smith, Richard D.; Hoffmann, Ralf

    2011-06-13

    Ion mobility spectrometry (IMS), and particularly differential IMS or field asymmetric waveform IMS (FAIMS), was recently shown capable of separating post-translationally modified peptides with variant PTM localization. However, that work was limited to a model peptide with serine phosphorylation on fairly distant alternative sites. Here, we demonstrate that FAIMS (coupled to ESI/MS) can broadly baseline-resolve variant phosphopeptides from a biologically modified human protein, including those involving phosphorylation of different residues and adjacent sites that existing MS/MS methods are most challenged to distinguish. Singly and doubly phosphorylated variants can be resolved equally well and identified without dissociation, based on accurate separation properties. The results are unchanged over a range of infusion solvent pH, hence present approach should work in conjunction with chromatographic separations using a mobile phase gradient.

  1. Enhancing bottom-up and top-down proteomic measurements with ion mobility separations

    PubMed Central

    Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Ibrahim, Yehia M.; Orton, Daniel J.; Monroe, Matthew E.; Kelly, Ryan T.; Moore, Ronald J.; Zhang, Xing; Théberge, Roger; Costello, Catherine E.; Smith, Richard D.

    2015-01-01

    Proteomic measurements with greater throughput, sensitivity, and structural information are essential for improving both in-depth characterization of complex mixtures and targeted studies. While LC separation coupled with MS (LC–MS) measurements have provided information on thousands of proteins in different sample types, the introduction of a separation stage that provides further component resolution and rapid structural information has many benefits in proteomic analyses. Technical advances in ion transmission and data acquisition have made ion mobility separations an opportune technology to be easily and effectively incorporated into LC–MS proteomic measurements for enhancing their information content. Herein, we report on applications illustrating increased sensitivity, throughput, and structural information by utilizing IMS–MS and LC–IMS–MS measurements for both bottom-up and top-down proteomics measurements. PMID:26046661

  2. Enhancing Bottom-up and Top-down Proteomic Measurements with Ion Mobility Separations

    SciTech Connect

    Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Ibrahim, Yehia M.; Orton, Daniel J.; Monroe, Matthew E.; Kelly, Ryan T.; Moore, Ronald J.; Zhang, Xing; Theberge, Roger; Costello, Catherine E.; Smith, Richard D.

    2015-07-03

    Proteomic measurements with greater throughput, sensitivity and additional structural information enhance the in-depth characterization of complex mixtures and targeted studies with additional information and higher confidence. While liquid chromatography separation coupled with mass spectrometry (LC-MS) measurements have provided information on thousands of proteins in different sample types, the additional of another rapid separation stage providing structural information has many benefits for analyses. Technical advances in ion funnels and multiplexing have enabled ion mobility separations to be easily and effectively coupled with LC-MS proteomics to enhance the information content of measurements. Finally, herein, we report on applications illustrating increased sensitivity, throughput, and structural information by utilizing IMS-MS and LC-IMS-MS measurements for both bottom-up and top-down proteomics measurements.

  3. Separation of Protein Conformers by Differential Ion Mobility in Hydrogen-Rich Gases

    SciTech Connect

    Shvartsburg, Alexandre A.; Smith, Richard D.

    2013-06-25

    Proteins in solution or the gas phase tend to exhibit multiple conformational families, each comprising distinct structures. Separation methods have generally failed to resolve these, with their convolution producing wide peaks. Here we report full separation of >10 conformers for most ubiquitin charge states by the new approach of differential ion mobility spectrometry (FAIMS) employing H2/N2 gas mixtures with up to 85% H2. The resolving power (up to 400) is five times the highest previously achieved (using He/N2 buffers), greatly increasing the separation specificity. The peak widths match the narrowest obtained by FAIMS for any species under same conditions and scale with the protein charge state (z) and ion residence time (t) as z-1/2 and t-1/2, as prescribed for instrumental (diffusional) broadening. This suggests resolution of specific geometries rather than broader ensembles.

  4. Enhancing Bottom-up and Top-down Proteomic Measurements with Ion Mobility Separations

    DOE PAGESBeta

    Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Ibrahim, Yehia M.; Orton, Daniel J.; Monroe, Matthew E.; Kelly, Ryan T.; Moore, Ronald J.; Zhang, Xing; Theberge, Roger; Costello, Catherine E.; et al

    2015-07-03

    Proteomic measurements with greater throughput, sensitivity and additional structural information enhance the in-depth characterization of complex mixtures and targeted studies with additional information and higher confidence. While liquid chromatography separation coupled with mass spectrometry (LC-MS) measurements have provided information on thousands of proteins in different sample types, the additional of another rapid separation stage providing structural information has many benefits for analyses. Technical advances in ion funnels and multiplexing have enabled ion mobility separations to be easily and effectively coupled with LC-MS proteomics to enhance the information content of measurements. Finally, herein, we report on applications illustrating increased sensitivity, throughput,more » and structural information by utilizing IMS-MS and LC-IMS-MS measurements for both bottom-up and top-down proteomics measurements.« less

  5. Characterizing the resolution and accuracy of a second-generation traveling-wave ion mobility separator for biomolecular ions.

    PubMed

    Zhong, Yueyang; Hyung, Suk-Joon; Ruotolo, Brandon T

    2011-09-01

    High-accuracy, high-resolution ion mobility measurements enable a vast array of important contemporary applications in biological chemistry. With the recent advent of both new, widely available commercial instrumentation and also new calibration datasets tailored for the aforementioned commercial instrumentation, the possibilities for extending such high performance measurements to a diverse set of applications have never been greater. Here, we assess the performance characteristics of a second-generation traveling-wave ion mobility separator, focusing on those figures of merit that lead to making measurements of collision cross-section having both high precision and high accuracy. Through performing a comprehensive survey of instrument parameters and settings, we find instrument conditions for optimized drift time resolution, cross-section resolution, and cross-section accuracy for a range of peptide, protein and multi-protein complex ions. Moreover, the conditions for high accuracy IM results are significantly different from those optimized for separation resolution, indicating that a balance between these two metrics must be attained for traveling wave IM separations of biomolecules. We also assess the effect of ion heating during IM separation on instrument performance.

  6. Separation and identification of isomeric glycopeptides by high field asymmetric waveform ion mobility spectrometry.

    PubMed

    Creese, Andrew J; Cooper, Helen J

    2012-03-01

    The analysis of intact glycopeptides by mass spectrometry is challenging due to the numerous possibilities for isomerization, both within the attached glycan and the location of the modification on the peptide backbone. Here, we demonstrate that high field asymmetric wave ion mobility spectrometry (FAIMS), also known as differential ion mobility, is able to separate isomeric O-linked glycopeptides that have identical sequences but differing sites of glycosylation. Two glycopeptides from the glycoprotein mucin 5AC, GT(GalNAc)TPSPVPTTSTTSAP and GTTPSPVPTTST(GalNAc)TSAP (where GalNAc is O-linked N-acetylgalactosamine), were shown to coelute following reversed-phase liquid chromatography. However, FAIMS analysis of the glycopeptides revealed that the compensation voltage ranges in which the peptides were transmitted differed. Thus, it is possible at certain compensation voltages to completely separate the glycopeptides. Separation of the glycopeptides was confirmed by unique reporter ions produced by supplemental activation electron transfer dissociation mass spectrometry. These fragments also enable localization of the site of glycosylation. The results suggest that glycan position plays a key role in determining gas-phase glycopeptide structure and have implications for the application of FAIMS in glycoproteomics.

  7. Differential Ion Mobility Separations in up to 100% Helium Using Microchips

    SciTech Connect

    Shvartsburg, Alexandre A.; Ibrahim, Yehia M.; Smith, Richard D.

    2014-01-09

    The performance of differential IMS (FAIMS) analyzers is much enhanced by gases comprising He, especially He/N2 buffers. However, electrical breakdown has limited the He fraction in those mixtures to ~50 - 75%, depending on the field strength. By Paschen law, the threshold field for breakdown increases at shorter distances. This allows FAIMS using chips with microscopic channels to utilize much stronger field intensities (E) than “full-size” analyzers with wider gaps. Here we show that those chips can employ higher He fractions up to 100%. Use of He-rich gases improves the resolution and resolution/sensitivity balance substantially, although less than for full-size analyzers. The optimum He fraction is ~80%, in line with first-principles theory. Hence one can now measure the dependences of ion mobility on E in pure He, where ion-molecule cross section calculations are much more tractable than in other gases that form deeper and more complex interaction potentials. This capability may facilitate quantitative modeling of high-field ion mobility behavior and thus FAIMS separation properties, which would enable a priori extraction of structural information about the ions from FAIMS data.

  8. Differential ion mobility separations in up to 100% helium using microchips.

    PubMed

    Shvartsburg, Alexandre A; Ibrahim, Yehia M; Smith, Richard D

    2014-03-01

    The performance of differential IMS (FAIMS) analyzers is much enhanced by gases comprising He, especially He/N2 mixtures. However, electrical breakdown has limited the He fraction to ~50%-75%, depending on the field strength. By the Paschen law, the threshold field for breakdown increases at shorter distances. This allows FAIMS using chips with microscopic channels to utilize much stronger field intensities (E) than "full-size" analyzers with wider gaps. Here we show that those chips can employ higher He fractions up to 100%. Use of He-rich gases improves the resolution and resolution/sensitivity balance substantially, although less than for full-size analyzers. The optimum He fraction is ~80%, in line with first-principles theory. Hence, one can now measure the dependences of ion mobility on E in pure He, where ion-molecule cross section calculations are much more tractable than in other gases that form deeper and more complex interaction potentials. This capability may facilitate quantitative modeling of high-field ion mobility behavior and, thus, FAIMS separation properties, which would enable a priori extraction of structural information about the ions.

  9. UV photodissociation of trapped ions following ion mobility separation in a Q-ToF mass spectrometer.

    PubMed

    Bellina, Bruno; Brown, Jeffery M; Ujma, Jakub; Murray, Paul; Giles, Kevin; Morris, Michael; Compagnon, Isabelle; Barran, Perdita E

    2014-12-21

    An ion mobility mass spectrometer has been modified to allow optical interrogation of ions with different mass-to-charge (m/z) ratios and/or mobilities (K). An ion gating and trapping procedure has been developed which allows us to store ions for several seconds enabling UV photodissociation (UVPD).

  10. Using a Buffer Gas Modifier to Change Separation Selectivity in Ion Mobility Spectrometry

    PubMed Central

    Fernández-Maestre, Roberto; Wu, Ching; Hill, Herbert H.

    2010-01-01

    The mobilities of a set of common α-amino acids, four tetraalkylammonium ions, 2,4-dimethyl pyridine (2,4-lutidine), 2,6-di-tert-butyl pyridine (DTBP), and valinol were determined using electrospray ionization-ion mobility spectrometry-quadrupole mass spectrometry (ESI-IMS-QMS) while introducing 2-butanol into the buffer gas. The mobilities of the test compounds decreased by varying extents with 2-butanol concentration in the mobility spectrometer. When the concentration of 2-butanol increased from 0.0 to 6.8 mmol m−3 (2.5×102 ppmv), percentage reductions in mobilities were: 13.6% (serine), 12.2% (threonine), 10.4% (methionine), 10.3% (tyrosine), 9.8% (valinol), 9.2% (phenylalanine), 7.8% (tryptophan), 5.6% (2,4-lutidine), 2.2% (DTBP), 1.0% (tetramethylammonium ion, TMA, and tetraethylammonium ion, TEA), 0.0% (tetrapropylammonium ion, TPA), and 0.3% (tetrabutylammonium ion, TBA). These variations in mobility depended on the size and steric hindrance on the charge of the ions, and were due to formation of large ion-2-butanol clusters. This selective variation in mobilities was applied to the resolution of a mixture of compounds with similar reduced mobilities such as serine and valinol, which overlapped in N2-only buffer gas in the IMS spectrum. The relative insensitivity of tetraalkylammonium ions and DTBP to the introduction of 2-butanol into the buffer gas was explained by steric hindrance of the four alkyl substituents in tetraalkylammonium ions and the two tert-butyl groups in DTBP, which shielded the positive charge of the ion from the attachment of 2-butanol molecules. Low buffer gas temperatures (100 °C) produced the largest reductions in mobilities by increasing ion-2-butanol interactions and formation of clusters; high temperatures (250 °C) prevented the formation of clusters, and no reduction in ion mobility was obtained with the introduction of 2-butanol into the buffer gas. Low temperatures and high concentrations of 2-butanol produced a series of

  11. The Influence of Drift Gas Composition on the Separation Mechanism in Traveling Wave Ion Mobility Spectrometry: Insight from Electrodynamic Simulations.

    PubMed

    May, Jody C; McLean, John A

    2003-06-01

    The influence of three different drift gases (helium, nitrogen, and argon) on the separation mechanism in traveling wave ion mobility spectrometry is explored through ion trajectory simulations which include considerations for ion diffusion based on kinetic theory and the electrodynamic traveling wave potential. The model developed for this work is an accurate depiction of a second-generation commercial traveling wave instrument. Three ion systems (cocaine, MDMA, and amphetamine) whose reduced mobility values have previously been measured in different drift gases are represented in the simulation model. The simulation results presented here provide a fundamental understanding of the separation mechanism in traveling wave, which is characterized by three regions of ion motion: (1) ions surfing on a single wave, (2) ions exhibiting intermittent roll-over onto subsequent waves, and (3) ions experiencing a steady state roll-over which repeats every few wave cycles. These regions of ion motion are accessed through changes in the gas pressure, wave amplitude, and wave velocity. Resolving power values extracted from simulated arrival times suggest that momentum transfer in helium gas is generally insufficient to access regions (2) and (3) where ion mobility separations occur. Ion mobility separations by traveling wave are predicted to be effectual for both nitrogen and argon, with slightly lower resolving power values observed for argon as a result of band-broadening due to collisional scattering. For the simulation conditions studied here, the resolving power in traveling wave plateaus between regions (2) and (3), with further increases in wave velocity contributing only minor improvements in separations.

  12. Separation and characterization of oxidized isomeric lipid-peptide adducts by ion mobility mass spectrometry.

    PubMed

    Milic, Ivana; Kipping, Marc; Hoffmann, Ralf; Fedorova, Maria

    2015-12-01

    Phospholipids are major components of cell membranes and lipoprotein complexes. They are prone to oxidation by endogenous and exogenous reactive oxygen species yielding a large variety of modified lipids including small aliphatic and phospholipid bound aldehydes and ketones. These carbonyls are strong electrophiles that can modify proteins and, thereby, alter their structures and functions triggering various pathophysiological conditions. The analysis of lipid-protein adducts by liquid chromatography-MS is challenged by their mixed chemical nature (polar peptide and hydrophobic lipid), low abundance in biological samples, and formation of multiple isomers. Thus, we investigated traveling wave ion mobility mass spectrometry (TWIMS) to analyze lipid-peptide adducts generated by incubating model peptides corresponding to the amphipathic β1 sheet sequence of apolipoprotein B-100 with 1-palmitoyl-2-(oxo-nonanoyl)-sn-glycerophosphatidylcholine (PONPC). The complex mixture of peptides, lipids, and peptide-lipid adducts was separated by TWIMS, which was especially important for the identification of two mono-PONPC-peptide isomers containing Schiff bases at different lysine residues. Moreover, TWIMS separated structural conformers of one peptide-lipid adduct possessing most likely different orientations of the hydrophobic sn-1 fatty acyl residue and head group of PONPC, relative to the peptide backbone. PMID:26634972

  13. Separation of Opiate Isomers Using Electrospray Ionization and Paper Spray Coupled to High-Field Asymmetric Waveform Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Manicke, Nicholas E.; Belford, Michael

    2015-05-01

    One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphone, and norcodeine. These isomers cannot be distinguished by tandem mass spectrometry. Separation prior to MS analysis is, therefore, required to distinguish these compounds, which are important in clinical chemistry and toxicology. FAIMS was coupled to a triple quadrupole mass spectrometer, and ionization was performed using either a pneumatically assisted heated electrospray ionization source (H-ESI) or paper spray, a direct analysis method that has been applied to the direct analysis of dried blood spots and other complex samples. We found that FAIMS was capable of separating the three opiate structural isomers using both H-ESI and paper spray as the ionization source.

  14. Identification and separation of saxitoxins using hydrophilic interaction liquid chromatography coupled to traveling wave ion mobility-mass spectrometry.

    PubMed

    Poyer, Salomé; Loutelier-Bourhis, Corinne; Coadou, Gaël; Mondeguer, Florence; Enche, Julien; Bossée, Anne; Hess, Philipp; Afonso, Carlos

    2015-01-01

    The aim of this work was to develop a reliable and efficient analytical method to characterise and differentiate saxitoxin analogues (STX), including sulphated (gonyautoxins, GTX) and non-sulphated analogues. For this purpose, hydrophilic interaction liquid chromatography (HILIC) was used to separate sulphated analogues. We also resorted to ion mobility spectrometry to differentiate the STX analogues because this technique adds a new dimension of separation based on ion gas phase conformation. Positive and negative ionisation modes were used for gonyautoxins while positive ionisation mode was used for non-sulphated analogues. Subsequently, the coupling of these three complementary techniques, HILIC-IM-MS, permitted the separation and identification of STX analogues; isomer differentiation was achieved in HILIC dimension while non-sulphated analogues were separated in the IM-MS dimension. Additional structural characteristics concerning the conformation of STXs could be obtained using IM-MS measurements. Thus, the collision cross sections (CCS) of STXs are reported for the first time in the positive ionisation mode. These experimental CCSs correlated well with the calculated CCS values using the trajectory method. PMID:25601690

  15. Ion mobility sensor system

    DOEpatents

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  16. Ultra-High Resolution Ion Mobility Separations Utilizing Traveling Waves in a 13 m Serpentine Path Length Structures for Lossless Ion Manipulations Module.

    PubMed

    Deng, Liulin; Ibrahim, Yehia M; Hamid, Ahmed M; Garimella, Sandilya V B; Webb, Ian K; Zheng, Xueyun; Prost, Spencer A; Sandoval, Jeremy A; Norheim, Randolph V; Anderson, Gordon A; Tolmachev, Aleksey V; Baker, Erin S; Smith, Richard D

    2016-09-20

    We report the development and initial evaluation of a 13 m path length Structures for Lossless Manipulations (SLIM) module for achieving high resolution separations using traveling waves (TW) with ion mobility (IM) spectrometry. The TW SLIM module was fabricated using two mirror-image printed circuit boards with appropriately configured RF, DC, and TW electrodes and positioned with a 2.75 mm intersurface gap. Ions were effectively confined in field-generated conduits between the surfaces by RF-generated pseudopotential fields and moved losslessly through a serpentine path including 44 "U" turns using TWs. The ion mobility resolution was characterized at different pressures, gaps between the SLIM surfaces, and TW and RF parameters. After initial optimization, the SLIM IM-MS module provided about 5-fold higher resolution separations than present commercially available drift tube or traveling wave IM-MS platforms. Peak capacity and peak generation rates achieved were 246 and 370 s(-1), respectively, at a TW speed of 148 m/s. The high resolution achieved in the TW SLIM IM-MS enabled, e.g., isomeric sugars (lacto-N-fucopentaose I and lacto-N-fucopentaose II) to be baseline resolved, and peptides from an albumin tryptic digest were much better resolved than with existing commercial IM-MS platforms. The present work also provides a foundation for the development of much higher resolution SLIM devices based upon both considerably longer path lengths and multipass designs. PMID:27531027

  17. Enhancement of biological mass spectrometry by using separations based on changes in ion mobility (FAIMS and DMS).

    PubMed

    Purves, Randy W

    2013-01-01

    Analysis of complex biological samples for low-level analytes by liquid chromatography-tandem mass spectrometry (LC-MS/MS) often requires additional selectivity. Differential mobility techniques (FAIMS and DMS) have been shown to enhance LC-MS/MS analyses by separating ions in the gas-phase on a millisecond timescale by use of a mechanism that is complementary to both liquid chromatography and mass spectrometry. In this overview, a simplified description of the operation of these devices is given and an example presented that illustrates the utility of FAIMS (DMS) for solving a challenging analytical assay. Important recent advances in the field, including work with gas modifiers, are presented, along with an outlook for the technology.

  18. Ultrahigh-Resolution Differential Ion Mobility Separations of Conformers for Proteins above 10 kDa: Onset of Dipole Alignment?

    SciTech Connect

    Shvartsburg, Alexandre A.

    2014-11-04

    Biomacromolecules tend to assume numerous structures in solution or the gas phase. It has been possible to resolve disparate conformational families but not unique geometries within each, and drastic peak broadening has been the bane of protein analyses by chromatography, electrophoresis, and ion mobility spectrometry (IMS). The new differential IMS (FAIMS) approach using hydrogen-rich gases was recently found to separate conformers of a small protein ubiquitin with same peak width and resolving power up to ~400 as for peptides. Present work explores the reach of this approach for larger proteins, exemplified by cytochrome c and myoglobin. Resolution similar to that for ubiquitin was largely achieved with longer separations, while the onset of peak broadening and coalescence with shorter separations suggests the limitation of present technique to proteins under ~20 kDa. This capability may enable distinguishing whole proteins with differing residue sequences or localizations of posttranslational modifications. Small features at negative compensation voltages that markedly grow from cytochrome c to myoglobin indicate the dipole alignment of rare conformers in accord with theory, further supporting the concept of pendular macroions in FAIMS.

  19. SEPARATION OF PLUTONYL IONS

    DOEpatents

    Connick, R.E.; McVey, Wm.H.

    1958-07-15

    A process is described for separating plutonyl ions from the acetate ions with which they are associated in certaln carrier precipitation methods of concentrating plutonium. The method consists in adding alkaline earth metal ions and subsequently alkalizing the solution, causing formation of an alkaltne earth plutonate precipitate. Barium hydroxide is used in a preferred embodiment since it provides alkaline earth metal ion and alkalizes the solution in one step forming insoluble barium platonate.

  20. Correlation ion mobility spectroscopy

    DOEpatents

    Pfeifer, Kent B.; Rohde, Steven B.

    2008-08-26

    Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

  1. Rapid Assessment of Human Amylin Aggregation and Its Inhibition by Copper(II) Ions by Laser Ablation Electrospray Ionization Mass Spectrometry with Ion Mobility Separation

    PubMed Central

    Donaldson, Robert P.; Jeremic, Aleksandar M.; Vertes, Akos

    2015-01-01

    Native electrospray ionization (ESI) mass spectrometry (MS) is often used to monitor noncovalent complex formation between peptides and ligands. The relatively low throughput of this technique, however, is not compatible with extensive screening. Laser ablation electrospray ionization (LAESI) MS combined with ion mobility separation (IMS) can analyze complex formation and provide conformation information within a matter of seconds. Islet amyloid polypeptide (IAPP) or amylin, a 37-amino acid residue peptide, is produced in pancreatic beta-cells through proteolytic cleavage of its prohormone. Both amylin and its precursor can aggregate and produce toxic oligomers and fibrils leading to cell death in the pancreas that can eventually contribute to the development of type 2 diabetes mellitus. The inhibitory effect of the copper(II) ion on amylin aggregation has been recently discovered, but details of the interaction remain unknown. Finding other more physiologically tolerated approaches requires large scale screening of potential inhibitors. Here, we demonstrate that LAESI-IMS-MS can reveal the binding stoichiometry, copper oxidation state, and the dissociation constant of human amylin–copper(II) complex. The conformations of hIAPP in the presence of copper(II) ions were also analyzed by IMS, and preferential association between the β-hairpin amylin monomer and the metal ion was found. The copper(II) ion exhibited strong association with the –HSSNN– residues of the amylin. In the absence of copper(II), amylin dimers were detected with collision cross sections consistent with monomers of β-hairpin conformation. When copper(II) was present in the solution, no dimers were detected. Thus, the copper(II) ions disrupt the association pathway to the formation of β-sheet rich amylin fibrils. Using LAESI-IMS-MS for the assessment of amylin–copper(II) interactions demonstrates the utility of this technique for the high-throughput screening of potential inhibitors of

  2. Miniaturized Ion Mobility Spectrometer

    NASA Technical Reports Server (NTRS)

    Kaye, William J. (Inventor); Stimac, Robert M. (Inventor)

    2015-01-01

    By utilizing the combination of a unique electronic ion injection control circuit in conjunction with a particularly designed drift cell construction, the instantly disclosed ion mobility spectrometer achieves increased levels of sensitivity, while achieving significant reductions in size and weight. The instant IMS is of a much simpler and easy to manufacture design, rugged and hermetically sealed, capable of operation at high temperatures to at least 250.degree. C., and is uniquely sensitive, particularly to explosive chemicals.

  3. Ion trapping and separation using potential wells

    SciTech Connect

    Butler, M.A.

    2000-01-04

    A new mode of operation for an ion mobility spectrometer (IMS) has been demonstrated that uses potential wells to trap and separate ions by their mobility. This mode of operation has been made feasible by the improvements in personal computers that now allow real-time control of the potentials on ring electrodes in the IMS drift tube. This mode of operation does not require a shutter grid and allows the accumulation of ions in the potential well to enhance the ion signal. Loss of ions from the potential well is controlled by the radial electric fields required by Gauss's law.

  4. Localization of Post-Translational Modifications in Peptide Mixtures via High-Resolution Differential Ion Mobility Separations Followed by Electron Transfer Dissociation

    NASA Astrophysics Data System (ADS)

    Baird, Matthew A.; Shvartsburg, Alexandre A.

    2016-09-01

    Precise localization of post-translational modifications (PTMs) on proteins and peptides is an outstanding challenge in proteomics. While electron transfer dissociation (ETD) has dramatically advanced PTM analyses, mixtures of localization variants that commonly coexist in cells often require prior separation. Although differential or field asymmetric waveform ion mobility spectrometry (FAIMS) achieves broad variant resolution, the need for standards to identify the features has limited the utility of approach. Here we demonstrate full a priori characterization of variant mixtures by high-resolution FAIMS coupled to ETD and the procedures to systematically extract the FAIMS spectra for all variants from such data.

  5. Enhanced lipid isomer separation in human plasma using reversed-phase UPLC with ion-mobility/high-resolution MS detection[S

    PubMed Central

    Damen, Carola W. N.; Isaac, Giorgis; Langridge, James; Hankemeier, Thomas; Vreeken, Rob J.

    2014-01-01

    An ultraperformance LC (UPLC) method for the separation of different lipid molecular species and lipid isomers using a stationary phase incorporating charged surface hybrid (CSH) technology is described. The resulting enhanced separation possibilities of the method are demonstrated using standards and human plasma extracts. Lipids were extracted from human plasma samples with the Bligh and Dyer method. Separation of lipids was achieved on a 100 × 2.1 mm inner diameter CSH C18 column using gradient elution with aqueous-acetonitrile-isopropanol mobile phases containing 10 mM ammonium formate/0.1% formic acid buffers at a flow rate of 0.4 ml/min. A UPLC run time of 20 min was routinely used, and a shorter method with a 10 min run time is also described. The method shows extremely stable retention times when human plasma extracts and a variety of biofluids or tissues are analyzed [intra-assay relative standard deviation (RSD) <0.385% and <0.451% for 20 and 10 min gradients, respectively (n = 5); interassay RSD <0.673% and <0.763% for 20 and 10 min gradients, respectively (n = 30)]. The UPLC system was coupled to a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer, equipped with a traveling wave ion-mobility cell. Besides demonstrating the separation for different lipids using the chromatographic method, we demonstrate the use of the ion-mobility MS platform for the structural elucidation of lipids. The method can now be used to elucidate structures of a wide variety of lipids in biological samples of different matrices. PMID:24891331

  6. Coulomb Repulsion in Miniature Ion Mobility Spectrometry

    SciTech Connect

    Xu, J.; Whitten, W.B.; Ramsey, J.M.

    1999-08-08

    We have undertaken a study of ion mobility resolution in a miniature ion mobility spectrometer with a drift channel 1.7 mm in diameter and 35 mm in length. The device attained a maximum resolution of 14 in separating ions of NO, O{sub 2}, and methyl iodine. The ions were generated by pulses from a frequency-quadrupled Nd:YAG laser. Broadening due to Coulomb repulsion was modeled theoretically and shown experimentally to have a major effect on the resolution of the miniature device.

  7. Differential mobility separation of leukotrienes and protectins.

    PubMed

    Jónasdóttir, Hulda S; Papan, Cyrus; Fabritz, Sebastian; Balas, Laurence; Durand, Thierry; Hardardottir, Ingibjorg; Freysdottir, Jona; Giera, Martin

    2015-01-01

    Differential mobility spectrometry (DMS) is capable of separating stereoisomeric molecular ions based on their mobility in an oscillating electrical field with an asymmetric waveform. Thus, it is an "orthogonal" technique to chromatography and (tandem) mass spectrometry. Bioactive lipids, particularly of the eicosanoid and docosanoid class feature numerous stereoisomers, which exhibit a highly specific structure-activity relationship. Moreover, the geometry of these compounds also reflects their biochemical origin. Therefore, the unambiguous characterization of related isomers of the eicosanoid and docosanoid classes is of fundamental importance to the understanding of their origin and function in many biological processes. Here we show, that SelexION DMS technology coupled to μLC-MS/MS is capable of differentiating at least five closely related leukotrienes partially coeluting and (almost) unresolvable using LC-MS/MS only. We applied the developed method to the separation of LTB4 and its coeluting isomer 5S,12S-diHETE in murine peritoneal exudate cells, showing that LTB4 is present only after zymosan A injection while its isomer 5S,12S-diHETE is produced after saline (PBS) administration. Additionally, we show that the SelexION technology can also be applied to the separation of PD1 and PDX (10S,17S-diHDHA), two isomeric protectins.

  8. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    PubMed

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI.

  9. Fundamentals of traveling wave ion mobility spectrometry.

    PubMed

    Shvartsburg, Alexandre A; Smith, Richard D

    2008-12-15

    Traveling wave ion mobility spectrometry (TW IMS) is a new IMS method implemented in the Synapt IMS/mass spectrometry system (Waters). Despite its wide adoption, the foundations of TW IMS were only qualitatively understood and factors governing the ion transit time (the separation parameter) and resolution remained murky. Here we develop the theory of TW IMS using derivations and ion dynamics simulations. The key parameter is the ratio (c) of ion drift velocity at the steepest wave slope to wave speed. At low c, the ion transit velocity is proportional to the squares of mobility (K) and electric field intensity (E), as opposed to linear scaling in drift tube (DT) IMS and differential mobility analyzers. At higher c, the scaling deviates from quadratic in a way controlled by the waveform profile, becoming more gradual with the ideal triangular profile but first steeper and then more gradual for realistic profiles with variable E. At highest c, the transit velocity asymptotically approaches the wave speed. Unlike with DT IMS, the resolving power of TW IMS depends on mobility, scaling as K(1/2) in the low-c limit and less at higher c. A nonlinear dependence of the transit time on mobility means that the true resolving power of TW IMS differs from that indicated by the spectrum. A near-optimum resolution is achievable over an approximately 300-400% range of mobilities. The major predicted trends are in agreement with TW IMS measurements for peptide ions as a function of mobility, wave amplitude, and gas pressure. The issues of proper TW IMS calibration and ion distortion by field heating are also discussed. The new quantitative understanding of TW IMS separations allows rational optimization of instrument design and operation and improved spectral calibration. PMID:18986171

  10. Differential Mobility Spectrometer with Spatial Ion Detector and Methods Related Thereto

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A. (Inventor); Kanik, Isik (Inventor); Duong, Vu A. (Inventor)

    2013-01-01

    Differential mobility spectrometer with spatial ion detector and methods related thereto are disclosed. The use of one or more spatial detector within differential mobility spectrometry can provide for the identification and separation of ions with similar mobility and mass.

  11. Ion mobility spectrometers and methods for ion mobility spectrometry

    SciTech Connect

    Dahl, David A; Scott, Jill R; Appelhans, Anthony D; McJunkin, Timothy R; Olson, John E

    2009-04-14

    An ion mobility spectrometer may include an inner electrode and an outer electrode arranged so that at least a portion of the outer electrode surrounds at least a portion of the inner electrode and defines a drift space therebetween. The inner and outer electrodes are electrically insulated from one another so that a non-linear electric field is created in the drift space when an electric potential is placed on the inner and outer electrodes. An ion source operatively associated with the ion mobility spectrometer releases ions to the drift space defined between the inner and outer electrodes. A detector operatively associated with at least a portion of the outer electrode detects ions from the drift space.

  12. Ion Mobility Spectrometry (IMS) and Mass Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.

    2010-04-20

    In a media of finite viscosity, the Coulomb force of external electric field moves ions with some terminal speed. This dynamics is controlled by “mobility” - a property of the interaction potential between ions and media molecules. This fact has been used to separate and characterize gas-phase ions in various modes of ion mobility spectrometry (IMS) developed since 1970. Commercial IMS devices were introduced in 1980-s for field detection of volatile traces such as explosives and chemical warfare agents. Coupling to soft-ionization sources, mass spectrometry (MS), and chromatographic methods in 1990-s had allowed IMS to handle complex samples, enabling new applications in biological and environmental analyses, nanoscience, and other areas. Since 2003, the introduction of commercial systems by major instrument vendors started bringing the IMS/MS capability to broad user community. The other major development of last decade has been the differential IMS or “field asymmetric waveform IMS” (FAIMS) that employs asymmetric time-dependent electric field to sort ions not by mobility itself, but by the difference between its values in strong and weak electric fields. Coupling of FAIMS to conventional IMS and stacking of conventional IMS stages have enabled two-dimensional separations that dramatically expand the power of ion mobility methods.

  13. Modeling vapor uptake induced mobility shifts in peptide ions observed with transversal modulation ion mobility spectrometry-mass spectrometry.

    PubMed

    Rawat, Vivek K; Vidal-de-Miguel, Guillermo; Hogan, Christopher J

    2015-10-21

    Low field ion mobility spectrometry-mass spectrometry (IMS-MS) techniques exhibit low orthogonality, as inverse mobility often scales with mass to charge ratio. This inadequacy can be mitigated by adding vapor dopants, which may cluster with analyte ions and shift their mobilities by amounts independent of both mass and mobility of the ion. It is therefore important to understand the interactions of vapor dopants with ions, to better quantify the extent of dopant facilitated mobility shifts. Here, we develop predictive models of vapor dopant facilitated mobility shifts, and compare model calculations to measurements of mobility shifts for peptide ions exposed to variable gas phase concentrations of isopropanol. Mobility measurements were made at atmospheric pressure and room temperature using a recently developed transversal modulation ion mobility spectrometer (TMIMS). Results are compared to three separate models, wherein mobility shifts due to vapor dopants are attributed to changes in gas composition and (I) no vapor dopant uptake is assumed, (II) site-specific dopant uptake by the ion is assumed (approximated via a Langmuir adsorption model), and (III) site-unspecific dopant uptake by the ion is assumed (approximated via a classical nucleation model). We find that mobility shifts in peptide ions are in excellent agreement with model II, site-specific binding predictions. Conversely, mobility shifts of tetraalkylammonium ions from previous measurements were compared with these models and best agreement was found with model III predictions, i.e. site-unspecific dopant uptake.

  14. An ion mobility mass spectrometer for investigating photoisomerization and photodissociation of molecular ions

    SciTech Connect

    Adamson, B. D.; Coughlan, N. J. A.; Markworth, P. B.; Bieske, E. J.; Continetti, R. E.

    2014-12-15

    An ion mobility mass spectrometry apparatus for investigating the photoisomerization and photodissociation of electrosprayed molecular ions in the gas phase is described. The device consists of a drift tube mobility spectrometer, with access for a laser beam that intercepts the drifting ion packet either coaxially or transversely, followed by a quadrupole mass filter. An ion gate halfway along the drift region allows the instrument to be used as a tandem ion mobility spectrometer, enabling mobility selection of ions prior to irradiation, with the photoisomer ions being separated over the second half of the drift tube. The utility of the device is illustrated with photoisomerization and photodissociation action spectra of carbocyanine molecular cations. The mobility resolution of the device for singly charged ions is typically 80 and it has a mass range of 100-440 Da, with the lower limit determined by the drive frequency for the ion funnels, and the upper limit by the quadrupole mass filter.

  15. Biomolecule Analysis by Ion Mobility Spectrometry

    PubMed Central

    Bohrer, Brian C.; Merenbloom, Samuel I.; Koeniger, Stormy L.; Hilderbrand, Amy E.; Clemmer, David E.

    2013-01-01

    Although nonnative protein conformations, including intermediates along the folding pathway and kinetically trapped misfolded species that disfavor the native state, are rarely isolated in the solution phase, they are often stable in the gas phase, where macromolecular ions from electrospray ionization can exist in varying charge states. Differences in the structures of nonnative conformations in the gas phase are often large enough to allow different shapes and charge states to be separated because of differences in their mobilities through a gas. Moreover, gentle collisional activation can be used to induce structural transformations. These new structures often have different mobilities. Thus, there is the possibility of developing a multidimensional separation that takes advantage of structural differences of multiple stable states. This review discusses how nonnative states differ in the gas phase compared with solution and presents an overview of early attempts to utilize and manipulate structures in order to develop ion mobility spectrometry as a rapid and sensitive technique for separating complex mixtures of biomolecules prior to mass spectrometry. PMID:20636082

  16. Miniature Ion-Mobility Spectrometer

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.

    2006-01-01

    The figure depicts a proposed miniature ion-mobility spectrometer that would be fabricated by micromachining. Unlike prior ion-mobility spectrometers, the proposed instrument would not be based on a time-of-flight principle and, consequently, would not have some of the disadvantageous characteristics of prior time-of-flight ion-mobility spectrometers. For example, one of these characteristics is the need for a bulky carrier-gas-feeding subsystem that includes a shutter gate to provide short pulses of gas in order to generate short pulses of ions. For another example, there is need for a complex device to generate pulses of ions from the pulses of gas and the device is capable of ionizing only a fraction of the incoming gas molecules; these characteristics preclude miniaturization. In contrast, the proposed instrument would not require a carrier-gas-feeding subsystem and would include a simple, highly compact device that would ionize all the molecules passing through it. The ionization device in the proposed instrument would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several megavolts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. Ionization (but not avalanche arcing) would occur because the distance between the ionizing electrodes would be less than the mean free path of gas molecules at the operating pressure of instrument. An accelerating grid would be located inside the instrument, downstream from the ionizing membrane. The electric potential applied to this grid would be negative relative to the potential on the inside electrode of the ionizing membrane and would be of a magnitude sufficient to

  17. Buffer Gas Modifiers Effect Resolution in Ion Mobility Spectrometry through Selective Ion-Molecule Clustering Reactions

    PubMed Central

    Fernández-Maestre, Roberto; Wu, Ching; Hill, Herbert H.

    2013-01-01

    RATIONALE When polar molecules (modifiers) are introduced into the buffer gas of an ion mobility spectrometer, most ion mobilities decrease due to the formation of ion-modifier clusters. METHODS We used ethyl lactate, nitrobenzene, 2-butanol, and tetrahydrofuran-2-carbonitrile as buffer gas modifiers and electrospray ionization ion mobility spectrometry (IMS) coupled to quadrupole mass spectrometry. Ethyl lactate, nitrobenzene, and tetrahydrofuran-2-carbonitrile had not been tested as buffer gas modifiers and 2-butanol had not been used with basic amino acids. RESULTS The ion mobilities of several diamines (arginine, histidine, lysine, and atenolol) were not affected or only slightly reduced when these modifiers were introduced into the buffer gas (3.4% average reduction in an analyte's mobility for the three modifiers). Intramolecular bridges caused limited change in the ion mobilities of diamines when modifiers were added to the buffer gas; these bridges hindered the attachment of modifier molecules to the positive charge of ions and delocalized the charge, which deterred clustering. There was also a tendency towards large changes in ion mobility when the mass of the analyte decreased; ethanolamine, the smallest compound tested, had the largest reduction in ion mobility with the introduction of modifiers into the buffer gas (61%). These differences in mobilities, together with the lack of shift in bridge-forming ions, were used to separate ions that overlapped in IMS, such as isoleucine and lysine, and arginine and phenylalanine, and made possible the prediction of separation or not of overlapping ions. CONCLUSIONS The introduction of modifiers into the buffer gas in IMS can selectively alter the mobilities of analytes to aid in compound identification and/or enable the separation of overlapping analyte peaks. PMID:22956312

  18. Chromatographic separation of inorganic ions on thin layers of titanium phosphate ion-exchanger.

    PubMed

    Ghoulipour, Vanik; Safari, Moharram

    2014-12-01

    The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous, organic and mixed mobile phases. The separation of one ion from several other ions and also ternary and binary separations have been developed. Some important analytical separations are reported. The effect of pH of the mobile phase on retention factor (Rf) values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied. This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationaiy phase in thin layer chromatography.

  19. Treatise on the Measurement of Molecular Masses with Ion Mobility Spectrometry

    PubMed Central

    Valentine, Stephen J.; Clemmer, David E.

    2009-01-01

    The ability to separate isotopes by high-resolution ion mobility spectrometry techniques is considered as a direct means for determining mass at ambient pressures. Calculations of peak shapes from the transport equation show that it should be possible to separate isotopes for low mass ions (<200) by utilizing heavy collision gasses and high resolution ion mobility analyzers. The mass accuracy associated with this isotopic separation approach based on ion mobility separation is considered. Finally, we predict several isotopes that should be separable. PMID:19548697

  20. Treatise on the measurement of molecular masses with ion mobility spectrometry.

    PubMed

    Valentine, Stephen J; Clemmer, David E

    2009-07-15

    The ability to separate isotopes by high-resolution ion mobility spectrometry techniques is considered as a direct means for determining mass at ambient pressures. Calculations of peak shapes from the transport equation show that it should be possible to separate isotopes for low-mass ions (<200) by utilizing heavy collision gases and high-resolution ion mobility analyzers. The mass accuracy associated with this isotopic separation approach based on ion mobility separation is considered. Finally, we predict several isotopes that should be separable.

  1. Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

    ERIC Educational Resources Information Center

    Johnson, Brian J.

    2014-01-01

    Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

  2. Mobility-Resolved Ion Selection in Uniform Drift Field Ion Mobility Spectrometry/Mass Spectrometry: Dynamic Switching in Structures for Lossless Ion Manipulations

    PubMed Central

    2015-01-01

    A Structures for Lossless Ion Manipulations (SLIM) module that allows ion mobility separations and the switching of ions between alternative drift paths is described. The SLIM switch component has a “Tee” configuration and allows the efficient switching of ions between a linear path and a 90-degree bend. By controlling switching times, ions can be efficiently directed to an alternative channel as a function of their mobilities. In the initial evaluation the switch is used in a static mode and shown compatible with high performance ion mobility separations at 4 Torr. In the dynamic mode, we show that mobility-selected ions can be switched into the alternative channel, and that various ion species can be independently selected based on their mobilities for time-of-flight mass spectrometer (TOF MS) IMS detection and mass analysis. This development also provides the basis of, for example, the selection of specific mobilities for storage and accumulation, and the key component of modules for the assembly of SLIM devices enabling much more complex sequences of ion manipulations. PMID:25222548

  3. [Ion mobility spectrometry for the isomeric volatile organic compounds].

    PubMed

    Han, Hai-yan; Jia, Xian-de; Huang, Guo-dong; Wang, Hong-mei; Li, Jian-quan; Jin, Shun-ping; Jiang, Hai-he; Chu, Yan-nan; Zhou, Shi-kang

    2007-10-01

    Ion mobility spectrometry (IMS) is based on determining the drift velocities, which the ionized sample molecules attain in the weak electric field of a drift tube at atmospheric pressure. The drift behavior can be affected by structural differences of the analytes, so that ion mobility spectrometry has the ability to separated isomeric compounds. In the present article, an introduction to IMS is given, followed by a description of the instrument used for the experiments to differentiate isomeric compounds. Positive ion mobility spectras of three kinds of isomeric volatile organic compounds were studied in a homemade high-resolution IMS apparatus with a discharge ionization source. The study includes the differences in the structure of carbon chain, the style of function group, and the position of function group. The reduced mobility values were determined, which are in very good agreement with the previously reported theoretical values using neural network theory. The influence of the structural features of the substances and including the size and shape of the molecule has been investigated. The reduced mobility values increases in the order: alcohols < acetones < aromas, linears < branches < cycles, and para- < meta- < ortho-. The deviating ion mobility spectra of the constitutional isomers studied reflect the influence of structural features. In order to calibrate or determine the detection limits and the sensitivity of the ion mobility spectrometry, the exponential dilution flask (EDF) was used. Using this method, the detection limit of the analytes can reach the order of magnitude of ng x L(-1).

  4. Ion mobility studies of electronically excited States of atomic transition metal cations: development of an ion mobility source for guided ion beam experiments.

    PubMed

    Iceman, Christopher; Rue, Chad; Moision, Robert M; Chatterjee, Barun K; Armentrout, P B

    2007-07-01

    The design of an ion mobility source developed to couple to a guided ion beam tandem mass spectrometer is presented. In these exploratory studies, metal ions are created continuously by electron ionization of the volatile hexacarbonyls of the three group 6 transition metals. These ions are focused into a linear hexapole ion trap, which collects the ions and then creates high intensity pulses of ions, avoiding excessive ion losses resulting from the low duty cycle of pulsed operation. The ion pulses are injected into a six-ring drift cell filled with helium where ions having different electronic configurations can separate because they have different ion mobilities. Such separation is observed for chromium ions and compares favorably with the pioneering work of Kemper and Bowers (J. Phys. Chem.1991, 95, 5134). The results are then extended to Mo(+) and W(+), which also show efficient configuration separation. The source conditions needed for high intensities and good configuration separation are discussed in detail and suggestions for further improvements are also provided.

  5. Ion mobility-mass spectrometry with a radial opposed migration ion and aerosol classifier (ROMIAC).

    PubMed

    Mui, Wilton; Thomas, Daniel A; Downard, Andrew J; Beauchamp, Jesse L; Seinfeld, John H; Flagan, Richard C

    2013-07-01

    The first application of a novel differential mobility analyzer, the radial opposed migration ion and aerosol classifier (ROMIAC), is demonstrated. The ROMIAC uses antiparallel forces from an electric field and a cross-flow gas to both scan ion mobilities and continuously transmit target mobility ions with 100% duty cycle. In the ROMIAC, diffusive losses are minimized, and resolution of ions, with collisional cross-sections of 200-2000 Å(2), is achieved near the nondispersive resolution of ~20. Higher resolution is theoretically possible with greater cross-flow rates. The ROMIAC was coupled to a linear trap quadrupole mass spectrometer and used to classify electrosprayed C2-C12 tetra-alkyl ammonium ions, bradykinin, angiotensin I, angiotensin II, bovine ubiquitin, and two pairs of model peptide isomers. Instrument and mobility calibrations of the ROMIAC show that it exhibits linear responses to changes in electrode potential, making the ROMIAC suitable for mobility and cross-section measurements. The high resolution of the ROMIAC facilitates separation of isobaric isomeric peptides. Monitoring distinct dissociation pathways associated with peptide isomers fully resolves overlapping peaks in the ion mobility data. The ability of the ROMIAC to operate at atmospheric pressure and serve as a front-end analyzer to continuously transmit ions with a particular mobility facilitates extensive studies of target molecules using a variety of mass spectrometric methods. PMID:23730869

  6. Ion separations based on electrical potentials nanoporous and microporous membranes

    NASA Astrophysics Data System (ADS)

    Armstrong, Jason

    This dissertation examines several types of ion separations in nanometer to micrometer pores in membranes. Membranes provide an attractive platform for ion separations, primarily because they operate continuously (i.e. not in a batch mode), and small pores offer the potential for ion separation based on charge and electrophoretic mobility differences. Initial studies employed charged, nanoporous membranes to separate monovalent and divalent ions. Adsorption of polyelectrolyte multilayers in nanoporous membranes afforded control over the surface charge and pore radii in track-etched membranes, and electrostatic ion-exclusion, particularly for divalent ions, occurred in these membranes because the electrical double layer filled the entire nanopore. Initial experiments employed adsorption of (PSS/PAH) multilayers in the 50-nm diameter pores of PCTE membranes to give a K+/Mg2+ selectivity of ~10 in pressure-driven dead-end filtration. Adsorption of (PSS/PAH) 1 films in 30-nm pores gave a similar K+/Mg2+ selectivity with a simpler modification procedure. Separations utilizing (PSS/PAH)1 films in 30-nm pores showed the lowest ion rejections with high ion concentrations, consistent with enhanced screening of the electrical double layer at high ionic strength. However, solutions with < 5 mM ionic strength exhibited essentially 100% Mg2+ rejections (the Mg2+ concentration in the permeate was below the method detection limit). Moreover, K+ rejections increased in the presence of Mg2+, which may stem from Mg2+-adsorption within the PEM and increased surface charge. Finally, separation of Br- and SO42- with a PSS1-modified, 30-nm PCTE membrane validated the exclusion mechanism for anions. The average Br-/SO42- selectivity was 3.4 +/- 0.8 for a solution containing 0.5 mM NaBr and 0.5 mM Na2SO4. The low selectivity in this case likely stems from a relatively large pore. The membranes used for the separation of monovalent and divalent ions also facilitated separation of

  7. Ion mobility spectrometer with virtual aperture grid

    DOEpatents

    Pfeifer, Kent B.; Rumpf, Arthur N.

    2010-11-23

    An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

  8. ICR Heating in Ion Separation Systems

    SciTech Connect

    Timofeev, A.V.

    2005-12-15

    A systematic procedure for analyzing the physical processes that govern ICR heating in systems for ion separation is developed. The procedure is based on an analytic model of an rf antenna generating rf fields within a plasma column in a magnetic field and includes such issues as the calculation of rf fields, examination of the ICR interaction of ions with these fields, and determination of the distribution function of the ion flow at the exit from the ICR heating system. It is shown that, even in ICR heating systems with easily achievable parameter values, ions with appreciably different masses can be efficiently separated by energy.

  9. Spatial Ion Peak Compression and its Utility in Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Garimella, Sandilya V. B.; Ibrahim, Yehia M.; Tang, Keqi; Webb, Ian K.; Baker, Erin S.; Tolmachev, Aleksey V.; Chen, Tsung-Chi; Anderson, Gordon A.; Smith, Richard D.

    2016-06-01

    A novel concept for ion spatial peak compression is described, and discussed primarily in the context of ion mobility spectrometry (IMS). Using theoretical and numerical methods, the effects of using non-constant (e.g., linearly varying) electric fields on ion distributions (e.g., an ion mobility peak) is evaluated both in the physical and temporal domains. The application of a linearly decreasing electric field in conjunction with conventional drift field arrangements is shown to lead to a reduction in IMS physical peak width. When multiple ion packets (i.e., peaks) in a selected mobility window are simultaneously subjected to such fields, there is ion packet compression (i.e., a reduction in peak widths for all species). This peak compression occurs with only a modest reduction of resolution, which can be quickly recovered as ions drift in a constant field after the compression event. Compression also yields a significant increase in peak intensities. Ion mobility peak compression can be particularly useful for mitigating diffusion-driven peak broadening over very long path length separations (e.g., in cyclic multi-pass arrangements), and for achieving higher S/N and IMS resolution over a selected mobility range.

  10. Spatial Ion Peak Compression and its Utility in Ion Mobility Spectrometry.

    PubMed

    Garimella, Sandilya V B; Ibrahim, Yehia M; Tang, Keqi; Webb, Ian K; Baker, Erin S; Tolmachev, Aleksey V; Chen, Tsung-Chi; Anderson, Gordon A; Smith, Richard D

    2016-06-01

    A novel concept for ion spatial peak compression is described, and discussed primarily in the context of ion mobility spectrometry (IMS). Using theoretical and numerical methods, the effects of using non-constant (e.g., linearly varying) electric fields on ion distributions (e.g., an ion mobility peak) is evaluated both in the physical and temporal domains. The application of a linearly decreasing electric field in conjunction with conventional drift field arrangements is shown to lead to a reduction in IMS physical peak width. When multiple ion packets (i.e., peaks) in a selected mobility window are simultaneously subjected to such fields, there is ion packet compression (i.e., a reduction in peak widths for all species). This peak compression occurs with only a modest reduction of resolution, which can be quickly recovered as ions drift in a constant field after the compression event. Compression also yields a significant increase in peak intensities. Ion mobility peak compression can be particularly useful for mitigating diffusion-driven peak broadening over very long path length separations (e.g., in cyclic multi-pass arrangements), and for achieving higher S/N and IMS resolution over a selected mobility range. Graphical Abstract ᅟ. PMID:27052738

  11. Spatial Ion Peak Compression and its Utility in Ion Mobility Spectrometry

    PubMed Central

    Garimella, Sandilya V. B.; Ibrahim, Yehia M.; Tang, Keqi; Webb, Ian K.; Baker, Erin S.; Tolmachev, Aleksey V.; Chen, Tsung-Chi; Anderson, Gordon A.; Smith, Richard D.

    2016-01-01

    A novel concept for ion spatial peak compression is described, and discussed primarily in the context of ion mobility spectrometry (IMS). Using theoretical and numerical methods, the effects of using non-constant (e.g., linearly varying) electric fields on ion distributions (e.g., an ion mobility peak) is evaluated both in the physical and temporal domains. The application of linearly decreasing electric field in conjunction with conventional drift field arrangements is shown to lead to a reduction in IMS physical peak width. When multiple ion packets (i.e. peaks) in a selected mobility window are simultaneously subjected to such fields, there is ion packet compression, i.e., a reduction in peak widths for all species. This peak compression occurs with only a modest reduction of resolution, and which can be quickly recovered as ions drift in a constant field after the compression event. Compression also yields a significant increase in peak intensities. Ion mobility peak compression can be particularly useful for mitigating diffusion driven peak spreading over very long path length separations (e.g., in cyclic multi-pass arrangements), and for achieving higher S/N and IMS resolution over a selected mobility range. PMID:27052738

  12. Pure inorganic separator for lithium ion batteries.

    PubMed

    He, Meinan; Zhang, Xinjie; Jiang, Kuiyang; Wang, Joe; Wang, Yan

    2015-01-14

    Battery safety is critical for many applications including portable electronics, hybrid and electric vehicles, and grid storage. For lithium ion batteries, the conventional polymer based separator is unstable at 120 °C and above. In this research, we have developed a pure aluminum oxide nanowire based separator; this separator does not contain any polymer additives or binders; additionally, it is a bendable ceramic. The physical and electrochemical properties of the separator are investigated. The separator has a pore size of about 100 nm, and it shows excellent electrochemical properties under both room and high temperatures. At room temperature, the ceramic separator shows a higher rate capability compared to the conventional Celgard 2500 separator and life cycle performance does not show any degradation. At 120 °C, the cell with the ceramic separator showed a much better cycle performance than the conventional Celgard 2500 separator. Therefore, we believe that this research is really an exciting scientific breakthrough for ceramic separators and lithium ion batteries and could be potentially used in the next generation lithium ion batteries requiring high safety and reliability.

  13. Mobility-Selected Ion Trapping and Enrichment Using Structures for Lossless Ion Manipulations

    DOE PAGESBeta

    Chen, Tsung-Chi; Ibrahim, Yehia M.; Webb, Ian K.; Garimella, Sandilya V. B.; Zhang, Xing; Hamid, Ahmed M.; Deng, Liulin; Karnesky, William E.; Prost, Spencer A.; Sandoval, Jeremy A.; et al

    2016-01-11

    The integration of ion mobility spectrometry (IMS) with mass spectrometry (MS) and the ability to trap ions in IMS-MS measurements is of great importance for performing reactions, accumulating ions, and increasing analytical measurement sensitivity. The development of Structures for Lossless Ion Manipulations (SLIM) offers the potential for ion manipulations in a more reliable and cost-effective manner, while opening opportunities for much more complex sequences of manipulations. Here, we demonstrate an ion separation and trapping module and a method based upon SLIM that consists of a linear mobility ion drift region, a switch/tee and a trapping region that allows the isolationmore » and accumulation of mobility-separated species. The operation and optimization of the SLIM switch/tee and trap are described and demonstrated for the enrichment of the low abundance ions. Lastly, we observed a linear increase in ion intensity with the number of trapping/accumulation events using the SLIM trap, illustrating its potential for enhancing the sensitivity of low abundance or targeted species.« less

  14. Separation of metal ions from aqueous solutions

    SciTech Connect

    Almon, A.

    1991-12-31

    This invention is comprised of a process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flowing cell containing flowing bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flowing cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flowing cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

  15. Separation of metal ions from aqueous solutions

    DOEpatents

    Almon, Amy C.

    1994-01-01

    A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

  16. Dual mode ion mobility spectrometer and method for ion mobility spectrometry

    DOEpatents

    Scott, Jill R [Idaho Falls, ID; Dahl, David A [Idaho Falls, ID; Miller, Carla J [Idaho Falls, ID; Tremblay, Paul L [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID

    2007-08-21

    Ion mobility spectrometer apparatus may include an ion interface that is operable to hold positive and negative ions and to simultaneously release positive and negative ions through respective positive and negative ion ports. A first drift chamber is operatively associated with the positive ion port of the ion interface and encloses an electric field therein. A first ion detector operatively associated with the first drift chamber detects positive ions from the first drift chamber. A second drift chamber is operatively associated with the negative ion port of the ion interface and encloses an electric field therein. A second ion detector operatively associated with the second drift chamber detects negative ions from said second drift chamber.

  17. Third International Workshop on Ion Mobility Spectrometry

    NASA Technical Reports Server (NTRS)

    Cross, John H. (Editor)

    1995-01-01

    Basic research in ion mobility spectrometry has given rise to rapid advancement in hardware development and applications. The Third International Workshop on Ion Mobility Spectrometry (IMS) was held October 16-19, 1994, at Johnson Space Center to provide a forum for investigators to present the most recent results of both basic and applied IMS research. Presenters included manufacturers and various users, including military research organizations and drug enforcement agencies. Thirty papers were given in the following five sessions: Fundamental IMS Studies, Instrument Development, Hyphenated IMS Techniques, Applications, and Data Reduction and Signal Processing. Advances in hardware development, software development, and user applications are described.

  18. Polyphosphazene membranes for metal ion separations

    SciTech Connect

    Stone, M.L.

    1996-05-01

    The Idaho National Engineering Laboratory (INEL), under sponsorship by the Bureau of Mines, evaluated the use of polyphosphazene-based polymer membranes for chemical separations. Synthetic membranes based on phosphazene inorganic polymers offer the promise of new industrial chemical separation technologies that are more energy efficient and economical than traditional phase change separation processes and extraction techniques. The research focused on the separation of metal ions from aqueous solutions. The polyphosphazene membranes were also tested for gaseous separations, results of which are presented in a separate Report of Investigation. Historically, membranes used for chemical separation have been prepared from organic polymers. In general, these membranes are stable only at temperatures less than 100{degrees}C, within narrow pH ranges, and in a very limited number of organic media. As a result, many organic- based membranes are unsuitable for industrial applications, which often involve harsh environments. In recent years, membrane research has focused on ceramic and metal membranes for use in the adverse environments of separation applications. These membranes are suitable for gas and liquid sieve separation applications, where molecules may be separated based on their molecular size. These membranes are not effective where additional selectivity is needed. A membrane that separates on the basis of solubility and that can perform separations in adverse environments is needed, and this need motivated the investigation of polyphosphazene membranes.

  19. Chemical Effects in the Separation Process of a Differential Mobility / Mass Spectrometer System

    PubMed Central

    Schneider, Bradley B.; Covey, Thomas R.; Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.

    2013-01-01

    In differential mobility spectrometry (DMS, also referred to as high field asymmetric waveform ion mobility spectrometry, FAIMS), ions are separated on the basis of the difference in their mobility under high and low electric fields. The addition of polar modifiers to the gas transporting the ions through a DMS enhances the formation of clusters in a field-dependent way and thus amplifies the high and low field mobility difference resulting in increased peak capacity and separation power. Observations of the increase in mobility field dependence are consistent with a cluster formation model, also referred to as the dynamic cluster-decluster model. The uniqueness of chemical interactions that occur between an ion and cluster-forming neutrals increases the selectivity of the separation and the depression of low-field mobility relative to high-field mobility increases the compensation voltage and peak capacity. The effect of polar modifiers on the peak capacity across a broad range of chemicals has been investigated. We discuss the theoretical underpinnings which explain the observed effects. In contrast to the result from polar modifiers, we find that using mixtures of inert gases as the transport gas improve resolution by reducing peak width but has very little effect on peak capacity or selectivity. Inert gases do not cluster and thus do not reduce low field mobility relative to high-field mobility. The observed changes in the differential mobility α parameter exhibited by different classes of compounds when the transport gas contains polar modifiers or has a significant fraction of inert gas can be explained on the basis of the physical mechanisms involved in the separation processes. PMID:20121077

  20. Distortion of Ion Structures by Field Asymmetric Waveform Ion Mobility Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.; Li, Fumin; Tang, Keqi; Smith, Richard D.

    2007-02-15

    Field asymmetric waveform ion mobility spectrometry (FAIMS) is emerging as a major analytical tool, especially in conjunction with mass spectrometry (MS) and/or conventional ion mobility spectrometry (IMS). In particular, FAIMS is used to separate protein or peptide conformers prior to characterization by IMS, MS/MS, or H/D exchange. High electric fields in FAIMS induce ion heating, previously estimated at <10 0C on average and believed too weak to affect ion geometries. Here we use a FAIMS/IMS/MS system to compare the IMS spectra for ESI-generated ubiquitin ions that have and have not passed FAIMS, and find that some unfolding occurs for all charge states. The analysis of those data and their comparison with reported protein unfolding in a Paul trap indicate that at least some structural transitions observed in FAIMS, or previously in an ion trap, are not spontaneous. The observed unfolding is overall similar to that produced by heating of ~40 - 50 0C above room temperature, consistent with the calculated heating of ions at FAIMS waveform peaks. Hence the isomerization in FAIMS likely proceeds in steps during “hot” periods, especially right after ions entering the device. That process distorts ion geometries and causes ion losses by a “self-cleaning” mechanism, and thus should be suppressed as much as possible. We propose achieving that via cooling FAIMS by the amount of ion heating; in most relevant cases cooling by ~75 0C should suffice.

  1. Ion mobility analysis of lipoproteins

    DOEpatents

    Benner, W. Henry; Krauss, Ronald M.; Blanche, Patricia J.

    2007-08-21

    A medical diagnostic method and instrumentation system for analyzing noncovalently bonded agglomerated biological particles is described. The method and system comprises: a method of preparation for the biological particles; an electrospray generator; an alpha particle radiation source; a differential mobility analyzer; a particle counter; and data acquisition and analysis means. The medical device is useful for the assessment of human diseases, such as cardiac disease risk and hyperlipidemia, by rapid quantitative analysis of lipoprotein fraction densities. Initially, purification procedures are described to reduce an initial blood sample to an analytical input to the instrument. The measured sizes from the analytical sample are correlated with densities, resulting in a spectrum of lipoprotein densities. The lipoprotein density distribution can then be used to characterize cardiac and other lipid-related health risks.

  2. Radio-Frequency (rf) Confinement in Ion Mobility Spectrometry: Apparent Mobilities and Effective Temperatures

    NASA Astrophysics Data System (ADS)

    Allen, Samuel J.; Bush, Matthew F.

    2016-08-01

    Ion mobility is a powerful tool for separating and characterizing the structures of ions. Here, a radio-frequency (rf) confining drift cell is used to evaluate the drift times of ions over a broad range of drift field strengths (E/P, V cm-1 Torr-1). The presence of rf potentials radially confines ions and results in excellent ion transmission at low E/P (less than 1 V cm-1 Torr-1), thereby reducing the dependence of ion transmission on the applied drift voltage. Non-linear responses between drift time and reciprocal drift voltages are observed for extremely low E/P and high rf amplitudes. Under these conditions, pseudopotential wells generated by the rf potentials dampen the mobility of ions. The effective potential approximation is used to characterize this mobility dampening behavior, which can be mitigated by adjusting rf amplitudes and electrode dimensions. Using SIMION trajectories and statistical arguments, the effective temperatures of ions in an rf-confining drift cell are evaluated. Results for the doubly charged peptide GRGDS suggest that applied rf potentials can result in a subtle increase (2 K) in effective temperature compared to an electrostatic drift tube. Additionally, simulations of native-like ions of the protein complex avidin suggest that rf potentials have a negligible effect on the effective temperature of these ions. In general, the results of this study suggest that applied rf potentials enable the measurement of drift times at extremely low E/P and that these potentials have negligible effects on ion effective temperature.

  3. Device for two-dimensional gas-phase separation and characterization of ion mixtures

    DOEpatents

    Tang, Keqi; Shvartsburg, Alexandre A.; Smith, Richard D.

    2006-12-12

    The present invention relates to a device for separation and characterization of gas-phase ions. The device incorporates an ion source, a field asymmetric waveform ion mobility spectrometry (FAIMS) analyzer, an ion mobility spectrometry (IMS) drift tube, and an ion detector. In one aspect of the invention, FAIMS operating voltages are electrically floated on top of the IMS drift voltage. In the other aspect, the FAIMS/IMS interface is implemented employing an electrodynamic ion funnel, including in particular an hourglass ion funnel. The present invention improves the efficiency (peak capacity) and sensitivity of gas-phase separations; the online FAIMS/IMS coupling creates a fundamentally novel two-dimensional gas-phase separation technology with high peak capacity, specificity, and exceptional throughput.

  4. Pendular proteins in gases and new avenues for characterization of macromolecules by ion mobility spectrometry

    PubMed Central

    Shvartsburg, Alexandre A.; Noskov, Sergei Y.; Purves, Randy W.; Smith, Richard D.

    2009-01-01

    Polar molecules align in electric fields when the dipole energy (proportional to field intensity E × dipole moment p) exceeds the thermal rotational energy. Small molecules have low p and align only at inordinately high E or upon extreme cooling. Many biomacromolecules and ions are strong permanent dipoles that align at E achievable in gases and room temperature. The collision cross-sections of aligned ions with gas molecules generally differ from orientationally averaged quantities, affecting ion mobilities measured in ion mobility spectrometry (IMS). Field asymmetric waveform IMS (FAIMS) separates ions by the difference between mobilities at high and low E and hence can resolve and identify macroion conformers based on the mobility difference between pendular and free rotor states. The exceptional sensitivity of that difference to ion geometry and charge distribution holds the potential for a powerful method for separation and characterization of macromolecular species. Theory predicts that the pendular alignment of ions in gases at any E requires a minimum p that depends on the ion mobility, gas pressure, and temperature. At ambient conditions used in current FAIMS systems, p for realistic ions must exceed ≈300–400 Debye. The dipole moments of proteins statistically increase with increasing mass, and such values are typical above ≈30 kDa. As expected for the dipole-aligned regime, FAIMS analyses of protein ions and complexes of ≈30–130 kDa show an order-of-magnitude expansion of separation space compared with smaller proteins and other ions. PMID:19351899

  5. Pendular Proteins in Gases and New Avenues for Characterization of Macromolecules by Ion Mobility Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.; Noskov, Sergei; Purves, Randy; Smith, Richard D.

    2009-04-21

    Polar molecules align in electric fields when the dipole energy (proportional to field intensity E × dipole moment p) exceeds the thermal rotational energy. Small molecules have low p and align only at inordinately high E or upon extreme cooling. Many biomacromolecules and ions are strong permanent dipoles and may align at E achievable in gases and room temperature. The collision cross sections of aligned ions with gas molecules generally differ from orientationally averaged quantities, affecting ion mobilities measured in ion mobility spectrometry (IMS). Field asymmetric waveform IMS (FAIMS) separates ions by the difference between mobilities at high and low E and hence can resolve and identify macroion conformers based on the mobility difference between pendular and free rotor states. An exceptional sensitivity of that difference to the ion geometry and charge distribution holds the potential for a powerful new method for separation and characterization of macromolecular species. Theory predicts that the pendular alignment of ions in gases at any E requires a minimum p depending on the ion mobility, gas pressure, and temperature. At ambient conditions used in current FAIMS systems, the p for realistic ions must exceed ~300 - 400 Debye. The dipole moments of proteins statistically increase with increasing mass, and such values are typical above ~30 kDa. FAIMS analyses of protein ions and complexes of ~30 - 130 kDa show an order-of-magnitude expansion of separation space compared to smaller proteins and other ions, consistent with expectations for the dipole-aligned regime.

  6. Organic ion exchange resin separation methods evaluation

    SciTech Connect

    Witwer, K.S.

    1998-05-27

    This document describes testing to find effective methods to separate Organic Ion Exchange Resin (OIER) from a sludge simulant. This task supports a comprehensive strategy for treatment and processing of K-Basin sludge. The simulant to be used resembles sludge that has accumulated in the 105KE and 105KW Basins in the 1OOK area of the Hanford Site. The sludge is an accumulation of fuel element corrosion products, organic and inorganic ion exchange materials, canister gasket materials, iron and aluminum corrosion products, sand, dirt, and other minor amounts of organic matter.

  7. Automated Deconvolution of Overlapped Ion Mobility Profiles

    NASA Astrophysics Data System (ADS)

    Brantley, Matthew; Zekavat, Behrooz; Harper, Brett; Mason, Rachel; Solouki, Touradj

    2014-10-01

    Presence of unresolved ion mobility (IM) profiles limits the efficient utilization of IM mass spectrometry (IM-MS) systems for isomer differentiation. Here, we introduce an automated ion mobility deconvolution (AIMD) computer software for streamlined deconvolution of overlapped IM-MS profiles. AIMD is based on a previously reported post-IM/collision-induced dissociation (CID) deconvolution approach [ J. Am. Soc. Mass Spectrom. 23, 1873 (2012)] and, unlike the previously reported manual approach, it does not require resampling of post-IM/CID data. A novel data preprocessing approach is utilized to improve the accuracy and efficiency of the deconvolution process. Results from AIMD analysis of overlapped IM profiles of data from (1) Waters Synapt G1 for a binary mixture of isomeric peptides (amino acid sequences: GRGDS and SDGRG) and (2) Waters Synapt G2-S for a binary mixture of isomeric trisaccharides (raffinose and isomaltotriose) are presented.

  8. Environment applications for ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Ritchie, Robert K.; Rudolph, Andreas

    1995-01-01

    The detection of environmentally important polychlorinated aromatics by ion mobility spectrometry (IMS) was investigated. Single polychlorinated biphenyl (PCB) isomers (congeners) having five or more chlorine atoms were reliably detected in isooctane solution at levels of 35 ng with a Barringer IONSCAN ion mobility spectrometer operating in negative mode; limits of detection (LOD) were extrapolated to be in the low ng region. Mixtures of up to four PCB congeners, showing characteristic multiple peaks, and complex commercial mixtures of PCBs (Aroclors) were also detected. Detection of Aroclors in transformer oil was suppressed by the presence of the antioxidant BHT (2,6-di-t-butyl4-methylphenol) in the oil. The wood preservative pentachlorophenol (PCP) was easily detected in recycled wood shavings at levels of 52 ppm with the IONSCAN; the LOD was extrapolated to be in the low ppm region.

  9. Process analysis using ion mobility spectrometry.

    PubMed

    Baumbach, J I

    2006-03-01

    Ion mobility spectrometry, originally used to detect chemical warfare agents, explosives and illegal drugs, is now frequently applied in the field of process analytics. The method combines both high sensitivity (detection limits down to the ng to pg per liter and ppb(v)/ppt(v) ranges) and relatively low technical expenditure with a high-speed data acquisition. In this paper, the working principles of IMS are summarized with respect to the advantages and disadvantages of the technique. Different ionization techniques, sample introduction methods and preseparation methods are considered. Proven applications of different types of ion mobility spectrometer (IMS) used at ISAS will be discussed in detail: monitoring of gas insulated substations, contamination in water, odoration of natural gas, human breath composition and metabolites of bacteria. The example applications discussed relate to purity (gas insulated substations), ecology (contamination of water resources), plants and person safety (odoration of natural gas), food quality control (molds and bacteria) and human health (breath analysis).

  10. Process analysis using ion mobility spectrometry.

    PubMed

    Baumbach, J I

    2006-03-01

    Ion mobility spectrometry, originally used to detect chemical warfare agents, explosives and illegal drugs, is now frequently applied in the field of process analytics. The method combines both high sensitivity (detection limits down to the ng to pg per liter and ppb(v)/ppt(v) ranges) and relatively low technical expenditure with a high-speed data acquisition. In this paper, the working principles of IMS are summarized with respect to the advantages and disadvantages of the technique. Different ionization techniques, sample introduction methods and preseparation methods are considered. Proven applications of different types of ion mobility spectrometer (IMS) used at ISAS will be discussed in detail: monitoring of gas insulated substations, contamination in water, odoration of natural gas, human breath composition and metabolites of bacteria. The example applications discussed relate to purity (gas insulated substations), ecology (contamination of water resources), plants and person safety (odoration of natural gas), food quality control (molds and bacteria) and human health (breath analysis). PMID:16132133

  11. Review on ion mobility spectrometry. Part 1: current instrumentation.

    PubMed

    Cumeras, R; Figueras, E; Davis, C E; Baumbach, J I; Gràcia, I

    2015-03-01

    Ion Mobility Spectrometry (IMS) is a widely used and 'well-known' technique of ion separation in the gaseous phase based on the differences in ion mobilities under an electric field. All IMS instruments operate with an electric field that provides space separation, but some IMS instruments also operate with a drift gas flow that provides also a temporal separation. In this review we will summarize the current IMS instrumentation. IMS techniques have received an increased interest as new instrumentation and have become available to be coupled with mass spectrometry (MS). For each of the eight types of IMS instruments reviewed it is mentioned whether they can be hyphenated with MS and whether they are commercially available. Finally, out of the described devices, the six most-consolidated ones are compared. The current review article is followed by a companion review article which details the IMS hyphenated techniques (mainly gas chromatography and mass spectrometry) and the factors that make the data from an IMS device change as a function of device parameters and sampling conditions. These reviews will provide the reader with an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465076

  12. Review on Ion Mobility Spectrometry. Part 1: Current Instrumentation

    PubMed Central

    Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

    2014-01-01

    Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. All IMS instruments operate with an electric field that provides space separation, but some IMS instruments also operate with a drift gas flow which provides also a temporal separation. In this review we will summarize the current IMS instrumentation. IMS techniques have received an increased interest as new instrumentation has become available to be coupled with mass spectrometry (MS). For each of the eight types of IMS instruments reviewed it is mentioned whether they can be hyphenated with MS and whether they are commercially available. Finally, out of the described devices, the six most-consolidated ones are compared. The current review article is followed by a companion review article which details the IMS hyphenated techniques (mainly gas chromatography and mass spectrometry) and the factors that make the data from an IMS device change as function of device parameters and sampling conditions. These reviews will provide the reader with an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465076

  13. Recoil separator ERNA: ion beam specifications

    NASA Astrophysics Data System (ADS)

    Rogalla, D.; Aliotta, M.; Barnes, C. A.; Campajola, L.; D'Onofrio, A.; Fritz, E.; Gialanella, L.; Greife, U.; Imbriani, G.; Ordine, A.; Ossmann, J.; Roca, V.; Rolfs, C.; Romano, M.; Sabbarese, C.; Schürmann, D.; Schümann, F.; Strieder, F.; Theis, S.; Terrasi, F.; Trautvetter, H. P.

    For improved measurements of the key astrophysical reaction 12C(α,γ)16O in inverted kinematics, a recoil separator ERNA is being developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with about 50% efficiency. Calculations of the ion beam optics including all filtering and focusing elements of ERNA are presented. Since the 12C projectiles and the 16O recoils have essentially the same momentum, and since the 12C ion beam emerging from the accelerator passes through a momentum filter (analysing magnet), the 12C ion beam must be as free as possible from 16O contamination for ERNA to succeed. In the present work, the 16O contamination was reduced from a level of 1 × 10-11 to a level below 2 × 10-29 by the installation of Wien filters both before and after the analysing magnet. The measurement of these and other beam specifications involved other parts of the final ERNA layout - sequentially a Wien filter, a 60˚ dipole magnet, another Wien filter, and a ΔE-E telescope. The setup led to a measured suppression factor of 5 × 10-18 for the 12C ion beam. The experiments also indicate that an almost free choice of the charge state for the 16O recoils is possible in the separator.

  14. How hot are your ions in TWAVE ion mobility spectrometry?

    PubMed

    Merenbloom, Samuel I; Flick, Tawnya G; Williams, Evan R

    2012-03-01

    Effective temperatures of ions during traveling wave ion mobility spectrometry (TWIMS) analysis were measured using singly protonated leucine enkephalin dimer as a chemical thermometer by monitoring dissociation of the dimer into monomer, as well as the subsequent dissociation of monomer into a-, b-, and y-ions, as a function of instrumental parameters. At fixed helium cell and TWIMS cell gas flow rates, the extent of dissociation does not vary significantly with either the wave velocity or wave height, except at low (<500 m/s) wave velocities that are not commonly used. Increasing the flow rate of nitrogen gas into the TWIMS cell and decreasing the flow rate of helium gas into the helium cell resulted in greater dissociation. However, the mobility distributions of the fragment ions formed by dissociation of the dimer upon injection into the TWIMS cell are nearly indistinguishable from those of fragment ions formed in the collision cell prior to TWIMS analysis for all TWIMS experiments. These results indicate that heating and dissociation occur when ions are injected into the TWIMS cell, and that the effective temperature subsequently decreases to a point at which no further dissociation is observed during the TWIMS analysis. An upper limit to the effective ion temperature of 449 K during TWIMS analysis is obtained at a helium flow rate of 180 mL/min, TWIMS flow rate of 80 mL/min, and traveling wave height of 40 V, which is well below previously reported values. Effects of ion heating in TWIMS on gas-phase protein conformation are presented.

  15. High-Sensitivity Ion Mobility Spectrometry/Mass Spectrometry Using Electrodynamic Ion Funnel Interfaces

    SciTech Connect

    Tang, Keqi; Shvartsburg, Alexandre A.; Lee, Hak-No; Prior, David C.; Buschbach, Michael A.; Li, Fumin; Tolmachev, Aleksey V.; Anderson, Gordon A.; Smith, Richard D.

    2005-05-15

    The utility of ion mobility spectrometry (IMS) for separation of mixtures and structural characterization of ions has been demonstrated extensively, including in the biological and nanoscience contexts. A major attraction of IMS is its speed, several orders of magnitude above that of condensed-phase separations. Nonetheless, IMS combined with mass spectrometry (MS) has remained a niche technique, substantially due to limited sensitivity resulting from ion losses at the IMS-MS junction. We have developed a new electrospray ionization (ESI)-IMS-QToF MS instrument that incorporates electrodynamic ion funnels at both front ESI-IMS and back IMS-QToF interfaces. The front funnel is of the novel ''hourglass'' design that efficiently accumulates ions and pulses them into the IMS drift tubes. Even for drift tubes of two meter length, ion transmission through IMS and on to QToF is essentially lossless across the range of ion masses relevant to most applications. The RF ion focusing at IMS terminus does not degrade IMS resolving power, which exceeds 100 (for singly-charged ions) and is close to the theoretical limit. The overall sensitivity of present ESI-IMS-MS system is shown to be comparable to that of commercial ESI-MS, which should make IMS-MS suitable for analyses of complex mixtures with ultra-high sensitivity and exceptional throughput.

  16. The ion mobility spectrometer for high explosive vapor detection

    SciTech Connect

    Cohen, M.J.; Stimac, R.M.; Wernlund, R.F.

    1984-07-01

    The Phemto-Chem /SUP R/ Model 100 Ion Mobility Spectrometer (IMS) operates in air and measures a number of explosive vapors at levels as low as partsper-trillion in seconds. The theory and operation of this instrument is discussed. The IMS inhales the vapor sample in a current of air and generates characteristic ions which are separated by time-of -ion drift in the atmospheric pressure gas. Quantitative results, using a dilution tunnel and standard signal generator with TNT, nitroglycerine, ethylene glycol dinitrate, cyclohexanone, methylamine, octafluoronaphthalene and hexafluorobenzene, are given. Rapid sample treatment with sample concentrations, microprocessor signal readout and chemical identification, offer a realistic opportunity of rapid explosive vapor detection at levels down to 10/sup -14/ parts by volume in air.

  17. Dielectric Properties and Ion Mobility in Erythrocytes

    PubMed Central

    Pauly, H.; Schwan, H. P.

    1966-01-01

    The impedance of erythrocytes of man, cattle, sheep, dog, cat, rabbit, and chicken was measured in the range from 0.5 to 250 Mc. The dielectric constant of the red cell interior is 50 at 250 Mc, varies but little with species, and can readily be accounted for by the cells' hemoglobin content. The electrical conductivity of the red cell interior was determined between 70 and 100 Mc. The values differ from species to species within the rather limited range from 4.4 to 5.3 mmho/cm. Removal of the cell membranes does not affect the conductivity. Hence, the cell interior behaves, from an electrical point of view, like a highly concentrated hemoglobin solution. A theoretical value for the electrical conductivity of erythrocyte interiors, which is calculated on the basis of the salt content of the cell, ion mobility, and the volume concentration of the hemoglobin, is roughly twice as large as the measured value. This discrepancy is typical not only of the red blood cell. Pertinent measurements show that it is probably caused by hydrodynamic and possibly by electrostatic effects also, which lower the mobility of the ions. From the lower electrical mobility it appears that a lowered diffusion constant of the electrolytes and nonelectrolytes within the cell is indicated. PMID:5970566

  18. Toward an Intelligent Ion Mobility Spectrometer (IMS)

    SciTech Connect

    Timothy R. McJunkin; Jill R. Scott; Carla J. Miller

    2003-07-01

    The ultimate goal is to design and build a very smart ion mobility spectrometer (IMS) that can operate autonomously. To accomplish this, software capable of interpreting spectra so that it can be used in control loops for data interpretation as well as adjusting instrument parameters is being developed. Fuzzy logic and fuzzy numbers are used in this IMS spectra classification scheme. Fuzzy logic provides a straight forward method for developing a classification/detection system, whenever rules for classifying the spectra can be described linguistically. Instead of using 'max' and 'min' values, the product of the truth values is used to determine class membership. Using the product allows rule-bases that utilize the AND function to allow each condition to discount truth value in determining membership, while rule-bases with an OR function are allowed to accumulate membership. Fuzzy numbers allow encapsulation of the uncertainties due to ion mobility peak widths as well as measured instrumental parameters, such as pressure and temperature. Associating a peak with a value of uncertainty, in addition to making adjustments to the mobility calculation based on variations in measured parameters, enables unexpected shifts to be more reliably detected and accounted for; thereby, reducing the opportunity for 'false negative' results. The measure of uncertainty is anticipated to serve the additional purpose of diagnosing the operational conditions of the IMS instrument.

  19. Trying to detect gas-phase ions? Understanding Ion Mobility Spectrometry

    PubMed Central

    Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

    2014-01-01

    Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. This technique has received increased interest over the last several decades as evidenced by the pace and advances of new IMS devices available. In this review we explore the hyphenated techniques that are used with IMS, especially mass spectrometry as identification approach and multi-capillary column as pre-separation approach. Also, we will pay special attention to the key figures of merit of the ion mobility spectrum and how data is treated, and the influences of the experimental parameters in both a conventional drift time IMS (DTIMS) and a miniaturized IMS also known as high Field Asymmetric IMS (FAIMS) in the planar configuration. The current review article is preceded by a companion review article which details the current instrumentation and to the sections that configures both a conventional DTIMS and FAIMS devices. Those reviews will give the reader an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465248

  20. Proton-bound cluster ions in ion mobility spectrometry.

    PubMed

    Ewing, R G; Eiceman, G A; Stone, J A

    1999-10-28

    Gaseous oxygen and nitrogen bases, both singly and as binary mixtures, have been introduced into ion mobility spectrometers to study the appearance of protonated molecules, and proton-bound dimers and trimers. At ambient temperature it was possible to simultaneously observe, following the introduction of molecule A, comparable intensities of peaks ascribable to the reactant ion (H2O)nH+, the protonated molecule AH+ and AH+ H2O, and the symmetrical proton bound dimer A2H+. Mass spectral identification confirmed the identifications and also showed that the majority of the protonated molecules were hydrated and that the proton-bound dimers were hydrated to a much lesser extent. No significant peaks ascribable to proton-bound trimers were obtained no matter how high the sample concentration. Binary mixtures containing molecules A and B, in some cases gave not only the peaks unique to the individual compounds but also peaks due to asymmetrical proton bound dimers AHB+. Such ions were always present in the spectra of mixtures of oxygen bases but were not observed for several mixtures of oxygen and nitrogen bases. The dimers, which were not observable, notable for their low hydrogen bond strengths, must have decomposed in their passage from the ion source to the detector, i.e. in a time less than approximately 5 ms. When the temperature was lowered to -20 degrees C, trimers, both homogeneous and mixed, were observed with mixtures of alcohols. The importance of hydrogen bond energy, and hence operating temperature, in determining the degree of solvation of the ions that will be observed in an ion mobility spectrometer is stressed. The possibility is discussed that a displacement reaction involving ambient water plays a role in the dissociation.

  1. Proton-bound cluster ions in ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Ewing, R. G.; Eiceman, G. A.; Stone, J. A.

    1999-01-01

    Gaseous oxygen and nitrogen bases, both singly and as binary mixtures, have been introduced into ion mobility spectrometers to study the appearance of protonated molecules, and proton-bound dimers and trimers. At ambient temperature it was possible to simultaneously observe, following the introduction of molecule A, comparable intensities of peaks ascribable to the reactant ion (H2O)nH+, the protonated molecule AH+ and AH+ H2O, and the symmetrical proton bound dimer A2H+. Mass spectral identification confirmed the identifications and also showed that the majority of the protonated molecules were hydrated and that the proton-bound dimers were hydrated to a much lesser extent. No significant peaks ascribable to proton-bound trimers were obtained no matter how high the sample concentration. Binary mixtures containing molecules A and B, in some cases gave not only the peaks unique to the individual compounds but also peaks due to asymmetrical proton bound dimers AHB+. Such ions were always present in the spectra of mixtures of oxygen bases but were not observed for several mixtures of oxygen and nitrogen bases. The dimers, which were not observable, notable for their low hydrogen bond strengths, must have decomposed in their passage from the ion source to the detector, i.e. in a time less than approximately 5 ms. When the temperature was lowered to -20 degrees C, trimers, both homogeneous and mixed, were observed with mixtures of alcohols. The importance of hydrogen bond energy, and hence operating temperature, in determining the degree of solvation of the ions that will be observed in an ion mobility spectrometer is stressed. The possibility is discussed that a displacement reaction involving ambient water plays a role in the dissociation.

  2. ION EXCHANGE ADSORPTION PROCESS FOR PLUTONIUM SEPARATION

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Taylor, M.D.

    1961-07-11

    Ion exchange processes for the separation of plutonium from fission products are described. In accordance with these processes an aqueous solution containing plutonium and fission products is contacted with a cation exchange resin under conditions favoring adsorption of plutonium and fission products on the resin. A portion of the fission product is then eluted with a solution containing 0.05 to 1% by weight of a carboxylic acid. Plutonium is next eluted with a solution containing 2 to 8 per cent by weight of the same carboxylic acid, and the remaining fission products on the resin are eluted with an aqueous solution containing over 10 per cent by weight of sodium bisulfate.

  3. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    SciTech Connect

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L.

    1996-08-01

    Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

  4. Ion mobility spectrometry for detection of skin volatiles

    PubMed Central

    Ruzsanyi, Veronika; Mochalski, Pawel; Schmid, Alex; Wiesenhofer, Helmut; Klieber, Martin; Hinterhuber, Hartmann; Amann, Anton

    2012-01-01

    Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin. PMID:23217311

  5. Signal processing for ION mobility spectrometers

    NASA Technical Reports Server (NTRS)

    Taylor, S.; Hinton, M.; Turner, R.

    1995-01-01

    Signal processing techniques for systems based upon Ion Mobility Spectrometry will be discussed in the light of 10 years of experience in the design of real-time IMS. Among the topics to be covered are compensation techniques for variations in the number density of the gas - the use of an internal standard (a reference peak) or pressure and temperature sensors. Sources of noise and methods for noise reduction will be discussed together with resolution limitations and the ability of deconvolution techniques to improve resolving power. The use of neural networks (either by themselves or as a component part of a processing system) will be reviewed.

  6. Fundamentals of Trapped Ion Mobility Spectrometry Part II: Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Silveira, Joshua A.; Michelmann, Karsten; Ridgeway, Mark E.; Park, Melvin A.

    2016-04-01

    Trapped ion mobility spectrometry (TIMS) is a new high resolution (R up to ~300) separation technique that utilizes an electric field to hold ions stationary against a moving gas. Recently, an analytical model for TIMS was derived and, in part, experimentally verified. A central, but not yet fully explored, component of the model involves the fluid dynamics at work. The present study characterizes the fluid dynamics in TIMS using simulations and ion mobility experiments. Results indicate that subsonic laminar flow develops in the analyzer, with pressure-dependent gas velocities between ~120 and 170 m/s measured at the position of ion elution. One of the key philosophical questions addressed is: how can mobility be measured in a dynamic system wherein the gas is expanding and its velocity is changing? We noted previously that the analytically useful work is primarily done on ions as they traverse the electric field gradient plateau in the analyzer. In the present work, we show that the position-dependent change in gas velocity on the plateau is balanced by a change in pressure and temperature, ultimately resulting in near position-independent drag force. That the drag force, and related variables, are nearly constant allows for the use of relatively simple equations to describe TIMS behavior. Nonetheless, we derive a more comprehensive model, which accounts for the spatial dependence of the flow variables. Experimental resolving power trends were found to be in close agreement with the theoretical dependence of the drag force, thus validating another principal component of TIMS theory.

  7. Ion mobilities in Xe/Ne and other rare-gas mixtures.

    PubMed

    Piscitelli, D; Phelps, A V; de Urquijo, J; Basurto, E; Pitchford, L C

    2003-10-01

    The ion mobility or drift velocity data important for modeling glow discharges in rare gas mixtures are not generally available, nor are the ion-neutral scattering cross sections needed to calculate these data. In this paper we propose a set of cross sections for Xe+ and Ne+ collisions with Xe and Ne atoms. Ion mobilities at 300 K calculated using this cross section set in a Monte Carlo simulation are reported for reduced field strengths, E/N, up to 1500 x 10(-21) V m(2), in pure gases and in Xe/Ne mixtures containing 5% and 20% Xe/Ne, which are mixtures of interest for plasma display panels (PDPs). The calculated Xe+ mobilities depend strongly on the mixture composition, but the Ne+ mobility varies only slightly with increasing Xe in the mixture over the range studied here. The mobilities in pure gases compare well with available experimental values, and mobilities in gas mixtures at low E/N compare well with our recent measurements which will be published separately. Results from these calculations of ion mobilities are used to evaluate the predictions of Blanc's law and of the mixture rule proposed by Mason and Hahn [Phys. Rev. A 5, 438 (1972)] for determining the ion mobilities in mixtures from a knowledge of the mobilities in each of the pure gases. The mixture rule of Mason and Hahn is accurate to better than 10% at high field strengths over a wide range of conditions of interest for modeling PDPs. We conclude that a good estimate of ion mobilities at high E/N in Xe/Ne and other binary rare gas mixtures can be obtained using this mixture rule combined with known values of mobilities in parent gases and with the Langevin form for mobility of rare gas ions ion in other gases. This conclusion is supported by results in Ar/Ne mixtures which are also presented here.

  8. QconCAT standard for calibration of ion mobility-mass spectrometry systems.

    PubMed

    Chawner, Ross; McCullough, Bryan; Giles, Kevin; Barran, Perdita E; Gaskell, Simon J; Eyers, Claire E

    2012-11-01

    Ion mobility-mass spectrometry (IM-MS) is a useful technique for determining information about analyte ion conformation in addition to mass/charge ratio. The physical principles that govern the mobility of an ion through a gas in the presence of a uniform electric field are well understood, enabling rotationally averaged collision cross sections (Ω) to be directly calculated from measured drift times under well-defined experimental conditions. However, such "first principle" calculations are not straightforward for Traveling Wave (T-Wave) mobility separations due to the range of factors that influence ion motion through the mobility cell. If collision cross section information is required from T-Wave mobility separations, then calibration of the instruments using known standards is essential for each set of experimental conditions. To facilitate such calibration, we have designed and generated an artificial protein based on the QconCAT technology, QCAL-IM, which upon proteolysis can be used as a universal ion mobility calibration standard. This single unique standard enables empirical calculation of peptide ion collision cross sections from the drift time on a T-Wave mobility instrument.

  9. Ion mobility spectrometry after supercritical fluid chromatography

    SciTech Connect

    Morrissey, M.A.

    1988-01-01

    In this work, a Fourier transform ion mobility spectrometer (FT-IMS) was constructed and evaluated as a detector for supercritical fluid chromatography (SFC). The FT-IMS provides both quantitative and qualitative data of a wide range of compounds, selective and nonselective modes of chromatographic detection, and it is compatible with a wide range of SFC mobile phases. Drift spectra are presented for a number of samples, including polymers, lipids, herbicides, antibiotics, and pharmaceuticals. The unique properties of supercritical fluids made it possible to introduce these compounds into the spectrometer. While the drift spectra presented are generally simple, showing only a quasi-molecular ion, a few are surprising complex. Examples of selective and non-selective detection demonstrate the usefulness of the detector. Examples are presented for fish oil concentrate, bacon grease extract, soil extract, and polymer mixtures. In the case of Triton X-100, a non-ionic surfactant, the FT-IMS was able to selectively detect individual oligomers in the polymer mixture. In the case of a polydimethylsilicone mixture the detector isolated a contaminant in the mixture.

  10. Analysis of phthalate esters by ion mobility spectrometry

    SciTech Connect

    Giam, C.S.; Reed, G.E.; Holliday, T.L.

    1995-12-31

    Esters of phthalic acid can be detected by IMS (ion mobility spectrometry). The six phthalates in the EPA`s Priority Pollutant List can be detected in both modes--positive as well as negative mode. In the positive mode, a characteristic reduced mobility was obtained for each phthalate; thus the different esters can be distinguished, including the isomeric di-n-octyl- and di-2-ethylhexyl phthalate. Phthalates can be detected in the low nanogram range; detection sensitivity is comparable or better than those found by gas chromatography using different detectors, including by GC-ECD, GC-FID or GC-MS. Direct Monitoring of environmental phthalates by IMS possess several advantages, e.g., without the usual separation protocols for ubiquitous interferants, faster instrumental analysis time (minutes instead of hours), and lower cost. Thus, IMS of phthalates has a great potential as an environmental monitor.

  11. High-field asymmetric waveform ion mobility spectrometry for mass spectrometry-based proteomics.

    PubMed

    Swearingen, Kristian E; Moritz, Robert L

    2012-10-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an atmospheric pressure ion mobility technique that separates gas-phase ions by their behavior in strong and weak electric fields. FAIMS is easily interfaced with electrospray ionization and has been implemented as an additional separation mode between liquid chromatography (LC) and mass spectrometry (MS) in proteomic studies. FAIMS separation is orthogonal to both LC and MS and is used as a means of on-line fractionation to improve the detection of peptides in complex samples. FAIMS improves dynamic range and concomitantly the detection limits of ions by filtering out chemical noise. FAIMS can also be used to remove interfering ion species and to select peptide charge states optimal for identification by tandem MS. Here, the authors review recent developments in LC-FAIMS-MS and its application to MS-based proteomics. PMID:23194268

  12. [Simultaneous separation of organic acid and organic salts by electrostatic ion chromatography].

    PubMed

    Shen, G J; Yang, R F; Yu, A M

    2001-09-01

    The electrostatic ion chromatographic column was prepared by coating conjugated acid salt micelles on the surface of octadecyl silica stationary phase. Pure water was used as mobile phase, and the conductance detector was connected on-line to electrostatic ion chromatograph. The conditions under which organic acid and organic salts were detected were studied. The mechanism for the above separation is discussed. Sodium benzoate and citric acid in Lichee drink were separated and determined. This method is rapid, simple with little interference and good reproducibility without any pollution since the mobile phase is water. This is an environmental friendly analytical method. PMID:12545440

  13. Reduction of air ion mobility to standard conditions

    NASA Astrophysics Data System (ADS)

    Tammet, H.

    1998-06-01

    The Langevin rule of the reduction of air ion mobility is adequate in case of zero-size ions. An alternative is the Stokes-Millikan equation that is adequate in the limit of macroscopic charged particles. The temperature variation of air ion mobility predicted by the Stokes-Millikan equation radically contradicts the Langevin rule. The temperature and pressure variation of air ion mobility is examined by using a new semiempirical model that describes the transition from the kinetic theory to the Stokes-Millikan equation. The model is valid in full mobility range. It allows to calculate at first the size of an ion according to the measured mobility and then the standard mobility according to the size. The ascent of the temperature-mobility curve on a logarithmic chart approaches the Langevin value of 1 only at very high mobilities not found in the atmosphere. The value of the ascent is 0.6 in the case of small ions of the mobility of 1.5 cm2 V-1 s-1 which brings about a considerable error when using the Langevin rule. It is recommended to store the natural values of the mobility in databases together with the values of temperature and pressure and to definitely indicate the method when the reduced mobilities are presented in publications.

  14. Ion mobility spectrometer for online monitoring of trace compounds1

    NASA Astrophysics Data System (ADS)

    Li, F.; Xie, Z.; Schmidt, H.; Sielemann, S.; Baumbach, J. I.

    2002-10-01

    The principle, character and developments of the instrumentation of ion mobility spectrometry are reviewed. The application of ion mobility spectrometers in monitoring chemical warfare agents, explosives, drugs, environmental hazardous compounds and industrial process control are discussed. Process applications with respect to miniaturization of the instrument are presented.

  15. Determining the isomeric heterogeneity of neutral oligosaccharide-alditols of bovine submaxillary mucin using negative ion traveling wave ion mobility mass spectrometry.

    PubMed

    Li, Hongli; Bendiak, Brad; Siems, William F; Gang, David R; Hill, Herbert H

    2015-02-17

    Negative ions produced by electrospray ionization were used to evaluate the isomeric heterogeneity of neutral oligosaccharide-alditols isolated from bovine submaxillary mucin (BSM). The oligosaccharide-alditol mixture was preseparated on an off-line high-performance liquid chromatography (HPLC) column, and the structural homogeneity of individual LC fractions was investigated using a Synapt G2 traveling wave ion mobility spectrometer coupled between quadupole and time-of-flight mass spectrometers. Mixtures of isomers separated by both chromatography and ion mobility spectrometry were studied. Tandem mass spectrometry (MS/MS) of multiple mobility peaks having the same mass-to-charge ratio (m/z) demonstrated the presence of different structural isomers and not differences in ion conformations due to charge site location. Although the oligosaccharide-alditol mixture was originally separated by HPLC, multiple ion mobility peaks due to structural isomers were observed for a number of oligosaccharide-alditols from single LC fractions. The collision-induced dissociation cells located in front of and after the ion mobility separation device enabled oligosaccharide precursor or product ions to be separated by ion mobility and independent fragmentation spectra to be acquired for isomeric carbohydrate precursor or product ions. MS/MS spectra so obtained for independent mobility peaks at a single m/z demonstrated the presence of structural variants or stereochemical isomers having the same molecular formula. This was observed both for oligosaccharide precursor and product ions. In addition, mobilities of both [M - H](-) and [M + Cl](-) ions, formed by adding NH4OH or NH4Cl to the electrospray solvent, were examined and compared for selected oligosaccharide-alditols. Better separation among structural isomers appeared to be achieved for some [M + Cl](-) anions.

  16. A novel Laser Ion Mobility Spectrometer

    NASA Astrophysics Data System (ADS)

    Göbel, J.; Kessler, M.; Langmeier, A.

    2009-05-01

    IMS is a well know technology within the range of security based applications. Its main advantages lie in the simplicity of measurement, along with a fast and sensitive detection method. Contemporary technology often fails due to interference substances, in conjunction with saturation effects and a low dynamic detection range. High throughput facilities, such as airports, require the analysis of many samples at low detection limits within a very short timeframe. High detection reliability is a requirement for safe and secure operation. In our present work we developed a laser based ion-mobility-sensor which shows several advantages over known IMS sensor technology. The goal of our research was to increase the sensitivity compared to the range of 63Ni based instruments. This was achieved with an optimised geometric drift tube design and a pulsed UV laser system at an efficient intensity. In this intensity range multi-photon ionisation is possible, which leads to higher selectivity in the ion-formation process itself. After high speed capturing of detection samples, a custom designed pattern recognition software toolbox provides reliable auto-detection capability with a learning algorithm and a graphical user interface.

  17. Comparison of the mobilities of negative and positive ions in nonpolar solutions.

    PubMed

    Ivanishko, Irina S; Borovkov, Vsevolod I

    2010-08-01

    The mobilities of organic radical ions of different molecular volumes have been determined in squalane and hexane solutions to study the influence of the ion charge sign on the ionic mobility in a weakly polar liquid. The relative mobility of geminate radical ions was measured using the method of time-resolved electric field effect in the recombination fluorescence. To determine the mobility of cations and anions separately, a trend in the value of the relative mobility was analyzed by varying the mobility of one of the geminate partners. The ratios between the mobilities of the anion and the cation of the same molecules were found to be about 1.1. It was shown that in liquid alkanes, the solvent electrostriction was the main factor determining a decrease in the mobility of an ion as compared to the parent neutral molecule. The strong dependence of the electrostrictive effect on the radius of the ionic solvation shell allows the observed difference between negative and positive charge carriers by a small but systematic difference in the effective radii of the ions to be explained.

  18. Mobility spectrum of air ions at Tahkuse Observatory

    NASA Astrophysics Data System (ADS)

    Horrak, U.; Iher, H.; Luts, A.; Salm, J.; Tammet, H.

    1994-05-01

    Mobility spectra of air ions have been measured at a rural site in Estonia during several periods. The annual average mobility spectrum of natural small air ions is presented. The concentrations of two groups of air ions with mobilities 0.32-0.5 sq cm/(V s) and 0.5-2.5 sq cm/(V s) are not correlated; this fact indicates the different nature of the ions of the two groups. The air ions with mobilities 0.5-2.5 sq cm/(V s) are interpreted as cluster ions and the air ions with mobilities 0.32-0.5 sq cm/(V s) as charged aerosol particles that can be created in the process of ion-induced nucleation. A half-year average mobility spectrum of the large ions with mobilities 3.2 x 10(exp -4) - 1.5/(V s) is presented. The spectrum is well interpreted on the basis of the average size distribution of aerosol particles and on the theory of diffusion charging of the particles.

  19. Simulating data processing for an Advanced Ion Mobility Mass Spectrometer

    SciTech Connect

    Chavarría-Miranda, Daniel; Clowers, Brian H.; Anderson, Gordon A.; Belov, Mikhail E.

    2007-11-03

    We have designed and implemented a Cray XD-1-based sim- ulation of data capture and signal processing for an ad- vanced Ion Mobility mass spectrometer (Hadamard trans- form Ion Mobility). Our simulation is a hybrid application that uses both an FPGA component and a CPU-based soft- ware component to simulate Ion Mobility mass spectrome- try data processing. The FPGA component includes data capture and accumulation, as well as a more sophisticated deconvolution algorithm based on a PNNL-developed en- hancement to standard Hadamard transform Ion Mobility spectrometry. The software portion is in charge of stream- ing data to the FPGA and collecting results. We expect the computational and memory addressing logic of the FPGA component to be portable to an instrument-attached FPGA board that can be interfaced with a Hadamard transform Ion Mobility mass spectrometer.

  20. Ion mobility mass spectrometry enables the efficient detection and identification of halogenated natural products from cyanobacteria with minimal sample preparation.

    PubMed

    Esquenazi, Eduardo; Daly, Michael; Bahrainwala, Tasneem; Gerwick, William H; Dorrestein, Pieter C

    2011-11-15

    Direct observation of halogenated natural products produced by different strains of marine cyanobacteria was accomplished by electrospray ionization and matrix assisted laser desorption ionization and gas phase separation via ion mobility mass spectrometry of extracts as well as intact organisms.

  1. Analysis of model Titan atmospheric components using ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Kojiro, D. R.; Cohen, M. J.; Wernlund, R. F.; Stimac, R. M.; Humphry, D. E.; Takeuchi, N.

    1991-01-01

    The Gas Chromatograph-Ion Mobility Spectrometer (GC-IMS) was proposed as an analytical technique for the analysis of Titan's atmosphere during the Cassini Mission. The IMS is an atmospheric pressure, chemical detector that produces an identifying spectrum of each chemical species measured. When the IMS is combined with a GC as a GC-IMS, the GC is used to separate the sample into its individual components, or perhaps small groups of components. The IMS is then used to detect, quantify, and identify each sample component. Conventional IMS detection and identification of sample components depends upon a source of energetic radiation, such as beta radiation, which ionizes the atmospheric pressure host gas. This primary ionization initiates a sequence of ion-molecule reactions leading to the formation of sufficiently energetic positive or negative ions, which in turn ionize most constituents in the sample. In conventional IMS, this reaction sequence is dominated by the water cluster ion. However, many of the light hydrocarbons expected in Titan's atmosphere cannot be analyzed by IMS using this mechanism at the concentrations expected. Research at NASA Ames and PCP Inc., has demonstrated IMS analysis of expected Titan atmospheric components, including saturated aliphatic hydrocarbons, using two alternate sample ionizations mechanisms. The sensitivity of the IMS to hydrocarbons such as propane and butane was increased by several orders of magnitude. Both ultra dry (waterless) IMS sample ionization and metastable ionization were successfully used to analyze a model Titan atmospheric gas mixture.

  2. Diffusion and Coulomb separation of ions in dense matter.

    PubMed

    Beznogov, M V; Yakovlev, D G

    2013-10-18

    We analyze diffusion equations in strongly coupled Coulomb mixtures of ions in dense stellar matter. Strong coupling of ions in the presence of gravitational forces and electric fields (induced by plasma polarization in the presence of gravity) produces a specific diffusion current which can separate ions with the same A/Z (mass to charge number) ratios but different Z. This Coulomb separation of ions can be important for the evolution of white dwarfs and neutron stars. PMID:24182248

  3. Ion mobility spectrometry for food quality and safety.

    PubMed

    Vautz, W; Zimmermann, D; Hartmann, M; Baumbach, J I; Nolte, J; Jung, J

    2006-11-01

    Ion mobility spectrometry is known to be a fast and sensitive technique for the detection of trace substances, and it is increasingly in demand not only for protection against explosives and chemical warfare agents, but also for new applications in medical diagnosis or process control. Generally, a gas phase sample is ionized by help of ultraviolet light, ss-radiation or partial discharges. The ions move in a weak electrical field towards a detector. During their drift they collide with a drift gas flowing in the opposite direction and, therefore, are slowed down depending on their size, shape and charge. As a result, different ions reach the detector at different drift times, which are characteristic for the ions considered. The number of ions reaching the detector are a measure of the concentration of the analyte. The method enables the identification and quantification of analytes with high sensitivity (ng l(-1) range). The selectivity can even be increased - as necessary for the analyses of complex mixtures - using pre-separation techniques such as gas chromatography or multi-capillary columns. No pre-concentration of the sample is necessary. Those characteristics of the method are preserved even in air with up to a 100% relative humidity rate. The suitability of the method for application in the field of food quality and safety - including storage, process and quality control as well as the characterization of food stuffs - was investigated in recent years for a number of representative examples, which are summarized in the following, including new studies as well: (1) the detection of metabolites from bacteria for the identification and control of their growth; (2) process control in food production - beer fermentation being an example; (3) the detection of the metabolites of mould for process control during cheese production, for quality control of raw materials or for the control of storage conditions; (4) the quality control of packaging materials during

  4. Identification of carbohydrate anomers using ion mobility-mass spectrometry.

    PubMed

    Hofmann, J; Hahm, H S; Seeberger, P H; Pagel, K

    2015-10-01

    Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

  5. Identification of carbohydrate anomers using ion mobility-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hofmann, J.; Hahm, H. S.; Seeberger, P. H.; Pagel, K.

    2015-10-01

    Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

  6. Secondary electrospray ionization ion mobility spectrometry/mass spectrometry of illicit drugs.

    PubMed

    Wu, C; Siems, W F; Hill, H H

    2000-01-15

    A secondary electrospray ionization (SESI) method was developed as a nonradioactive ionization source for ion mobility spectrometry (IMS). This SESI method relied on the gas-phase interaction between charged particles created by electrospray ionization (ESI) and neutral gaseous sample molecules. Mass spectrometry (MS) was used as the detection method after ion mobility separation for ion identification. Preliminary investigations focussed on understanding the ionization process of SESI. The performance of ESI-IMS and SESI-IMS for illicit drug detection was evaluated by determining the analytical figures of merit. In general, SESI had a higher ionization efficiency for small volatile molecules compared with the electrospray method. The potential of developing a universal interface for both GC- and LC-MS with an addition stage of mobility separation was demonstrated.

  7. Ion Mobility Mass Spectrometry Direct Isotope Abundance Analysis

    SciTech Connect

    Manuel J. Manard, Stephan Weeks, Kevin Kyle

    2010-05-27

    The nuclear forensics community is currently engaged in the analysis of illicit nuclear or radioactive material for the purposes of non-proliferations and attribution. One technique commonly employed for gathering nuclear forensics information is isotope analysis. At present, the state-of-the-art methodology for obtaining isotopic distributions is thermal ionization mass spectrometry (TIMS). Although TIMS is highly accurate at determining isotope distributions, the technique requires an elementally pure sample to perform the measurement. The required radiochemical separations give rise to sample preparation times that can be in excess of one to two weeks. Clearly, the nuclear forensics community is in need of instrumentation and methods that can expedite their decision making process in the event of a radiological release or nuclear detonation. Accordingly, we are developing instrumentation that couples a high resolution IM drift cell to the front end of a MS. The IM cell provides a means of separating ions based upon their collision cross-section and mass-to-charge ratio (m/z). Two analytes with the same m/z, but with different collision cross-sections (shapes) would exit the cell at different times, essentially enabling the cell to function in a similar manner to a gas chromatography (GC) column. Thus, molecular and atomic isobaric interferences can be effectively removed from the ion beam. The mobility selected chemical species could then be introduced to a MS for high-resolution mass analysis to generate isotopic distributions of the target analytes. The outcome would be an IM/MS system capable of accurately measuring isotopic distributions while concurrently eliminating isobaric interferences and laboratory radiochemical sample preparation. The overall objective of this project is developing instrumentation and methods to produce near real-time isotope distributions with a modular mass spectrometric system that performs the required gas-phase chemistry and

  8. Field applications of ion-mobility spectrometry

    NASA Astrophysics Data System (ADS)

    Brown, Patricia A.

    1997-02-01

    Ion mobility spectrometry (IMS) is an excellent tool for detection of controlled substances under field conditions. Plasmagrams and tables showing the results of field applications will be discussed. Residues of drugs, such as cocaine and heroin, can be left anywhere including vehicles, boats, and houses. In houses, the carpets, walls, and floors are good locations for residues to adhere. Individual clothing can also be contaminated with drug residue. Vehicles that are suspected of having previously smuggled illegal substances can be vacuumed and screened. Tablets that look similar and respond the same when screened with the Marquis reagent can be differentiated by IMS. With Southern California being the 'methamphetamine capital of the world' and the resurgence of phencyclidine, IMS has proven extremely valuable in the screening of abandoned clandestine laboratory sites and vehicles in which the clandestine laboratories; chemicals and glassware were transported. IMS is very responsive to ephedrine/pseudophedrine, a precursor of methamphetamine and 1-piperidinocyclohexanecarbonitrile, an intermediate of phencyclidine. Once residues are detected, vacuum samples, and/or methanol wipes are collected and analyzed at the DEA Laboratory for confirmation of the suspected substance using GC-IRD or Mass Spectrometry.

  9. A compact high resolution electrospray ionization ion mobility spectrometer.

    PubMed

    Reinecke, T; Kirk, A T; Ahrens, A; Raddatz, C-R; Thoben, C; Zimmermann, S

    2016-04-01

    Electrospray is a commonly used ionization method for the analysis of liquids. An electrospray is a dispersed nebular of charged droplets produced under the influence of a strong electrical field. Subsequently, ions are produced in a complex process initiated by evaporation of neutral solvent molecules from these droplets. We coupled an electrospray ionization source to our previously described high resolution ion mobility spectrometer with 75 mm drift tube length and a drift voltage of 5 kV. When using a tritium source for chemical gas phase ionization, a resolving power of R=100 was reported for this setup. We replaced the tritium source and the field switching shutter by an electrospray needle, a desolvation region with variable length and a three-grid shutter for injecting ions into the drift region. Preliminary measurements with tetraalkylammonium halides show that the current configuration with the electrospray ionization source maintains the resolving power of R=100. In this work, we present the characterization of our setup. One major advantage of our setup is that the desolvation region can be heated separately from the drift region so that the temperature in the drift region stays at room temperature even up to desolvation region temperatures of 100 °C. We perform parametric studies for the investigation of the influence of temperature on solvent evaporation with different ratios of water and methanol in the solvent for different analyte substances. Furthermore, the setup is operated in negative mode and spectra of bentazon with different solvents are presented.

  10. Anomerization of Acrylated Glucose During Traveling Wave Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Chendo, Christophe; Moreira, Guillaume; Tintaru, Aura; Posocco, Paola; Laurini, Erik; Lefay, Catherine; Gigmes, Didier; Viel, Stéphane; Pricl, Sabrina; Charles, Laurence

    2015-09-01

    Anomerization of simple sugars in the liquid phase is known as an acid- and base-catalyzed process, which highly depends on solvent polarity. This reaction is reported here to occur in the gas phase, during traveling wave ion mobility spectrometry (TWIMS) experiments aimed at separating α- and β-anomers of penta-acrylated glucose generated as ammonium adducts in electrospray ionization. This compound was available in two samples prepared from glucose dissolved in solvents of different polarity, namely tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAC), and analyzed by electrospray tandem mass spectrometry (ESI-MS/MS) as well as traveling wave ion mobility (ESI-TWIMS-MS). In MS/MS, an anchimerically-assisted process was found to be unique to the electrosprayed α-anomer, and was only observed for the THF sample. In ESI-TWIMS-MS, a signal was measured at the drift time expected for the α-anomer for both the THF and DMAC samples, in apparent contradiction to the MS/MS results, which indicated that the α-anomer was not present in the DMAC sample. However, MS/MS experiments performed after TWIMS separation revealed that ammonium adducts of the α-anomer produced from each sample, although exhibiting the same collision cross section, were clearly different. Indeed, while the α-anomer actually present in the THF sample was electrosprayed with the ammonium adducted at the C2 acrylate, its homologue only observed when the DMAC sample was subjected to TWIMS hold the adducted ammonium at the C1 acrylate. These findings were explained by a β/α inter-conversion upon injection in the TWIMS cell, as supported by theoretical calculation and dynamic molecular modeling.

  11. Ion mobility studies of carbohydrates as group I adducts: isomer specific collisional cross section dependence on metal ion radius.

    PubMed

    Huang, Yuting; Dodds, Eric D

    2013-10-15

    Carbohydrates play numerous critical roles in biological systems. Characterization of oligosaccharide structures is essential to a complete understanding of their functions in biological processes; nevertheless, their structural determination remains challenging in part due to isomerism. Ion mobility spectrometry provides the means to resolve gas phase ions on the basis of their shape-to-charge ratios, thus providing significant potential for separation and differentiation of carbohydrate isomers. Here, we report on the determination of collisional cross sections for four groups of isomeric carbohydrates (including five isomeric disaccharides, four isomeric trisaccharides, two isomeric pentasaccharides, and two isomeric hexasaccharides) as their group I metal ion adducts (i.e., [M + Li](+), [M + Na](+), [M + K](+), [M + Rb](+), and [M + Cs](+)). In all, 65 collisional cross sections were measured, the great majority of which have not been previously reported. As anticipated, the collisional cross sections of the carbohydrate metal ion adducts generally increase with increasing metal ion radius; however, the collisional cross sections were found to scale with the group I cation size in isomer specific manners. Such measurements are of substantial analytical value, as they illustrate how the selection of charge carrier influences carbohydrate ion mobility determinations. For example, certain pairs of isomeric carbohydrates assume unique collisional cross sections upon binding one metal ion, but not another. On the whole, these data suggest a role for the charge carrier as a probe of carbohydrate structure and thus have significant implications for the continued development and application of ion mobility spectrometry for the distinction and resolution of isomeric carbohydrates.

  12. Dynamically Multiplexed Ion Mobility Time-of-Flight Mass Spectrometry

    SciTech Connect

    Belov, Mikhail E.; Clowers, Brian H.; Prior, David C.; Danielson, William F.; Liyu, Andrei V.; Petritis, Brianne O.; Smith, Richard D.

    2008-08-01

    Ion Mobility Spectrometry–Time-of-Flight Mass Spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity high-throughput platform for e.g. proteomics applications. In this work, we have developed and integrated three advanced technologies, enabling (1) efficient ion accumulation in the ion funnel trap prior to IMS separation, (2) multiplexing (MP) of ion packet introduction into the IMS drift tube and (3) signal detection with an analog-to-digital converter (ADC), into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of e.g. blood plasma. To better address variable sample complexity, we have additionally developed and rigorously evaluated a new dynamic MP approach that ensures correlation of the analyzer performance with an ion source function, and provides the improved dynamic range and sensitivity. The MP IMS-TOF MS instrument has been shown to reliably detect peptides at a concentration of 1 nM in a highly complex matrix, as well as to provide a four orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features yielded ~ 700 unique peptide identifications at a false discovery rate (FDR) of ~ 7.5 %. Accounting for IMS information gave rise to a projected FDR of ~ 4 %. Signal reproducibility was found to be greater than 80 %, while the variations in the number of unique peptide identifications were < 15 %. A single sample analysis was completed in 15 min, corresponding to approximately an order of magnitude improvement compared to a more conventional LC-MS approach.

  13. Progress in metal ion separation and preconcentration : an overview.

    SciTech Connect

    Bond, A. H.

    1998-05-19

    A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented.

  14. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Glover, Matthew S.; Dilger, Jonathan M.; Acton, Matthew D.; Arnold, Randy J.; Radivojac, Predrag; Clemmer, David E.

    2016-05-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/ trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences.

  15. Analysis of Ultra-Pure Gases by Ion Mobility Spectrometry

    NASA Technical Reports Server (NTRS)

    Stimac, Robert M.; Wernlund, Roger F.; Cohen, Martin J.

    1995-01-01

    Work has continued with the evaluation of the Ion Mobility Spectrometer (IMS) for the analysis of gases having low parts-per-billion (10(exp -9)) water concentration. A modified PCP, inc. MMS-160 Mobility Mass Spectrometer System was used for the analysis of ultra-pure argon and nitrogen. The MMS-160 system permits the mass-identification of unique reactant and product ions observed in the reduced-water host gases. When the water is removed to low ppb levels, higher energy reactant ions are observed. In nitrogen, distinct odd- and even-numbered nitrogen cluster ion mobility peaks are observed, as well as adduct ion peaks from the trace contaminants in the gas. Argon also produces a cluster ion mobility peak and adduct ion peaks from trace components in the gas. Levels of contaminants in these ultra-pure gases can be determined from the ion mobility spectra. A calibrated source was used to provide variable known quantities of water to the pure gas supply of the IMS.

  16. Extending the Dynamic Range of the Ion Trap by Differential Mobility Filtration

    NASA Astrophysics Data System (ADS)

    Hall, Adam B.; Coy, Stephen L.; Kafle, Amol; Glick, James; Nazarov, Erkinjon; Vouros, Paul

    2013-09-01

    A miniature, planar, differential ion mobility spectrometer (DMS) was interfaced to an LCQ classic ion trap to conduct selective ion filtration prior to mass analysis in order to extend the dynamic range of the trap. Space charge effects are known to limit the functional ion storage capacity of ion trap mass analyzers and this, in turn, can affect the quality of the mass spectral data generated. This problem is further exacerbated in the analysis of mixtures where the indiscriminate introduction of matrix ions results in premature trap saturation with non-targeted species, thereby reducing the number of parent ions that may be used to conduct MS/MS experiments for quantitation or other diagnostic studies. We show that conducting differential mobility-based separations prior to mass analysis allows the isolation of targeted analytes from electrosprayed mixtures preventing the indiscriminate introduction of matrix ions and premature trap saturation with analytically unrelated species. Coupling these two analytical techniques is shown to enhance the detection of a targeted drug metabolite from a biological matrix. In its capacity as a selective ion filter, the DMS can improve the analytical performance of analyzers such as quadrupole (3D or linear) and ion cyclotron resonance (FT-ICR) ion traps that depend on ion accumulation.

  17. Extending the Dynamic Range of the Ion Trap by Differential Mobility Filtration

    PubMed Central

    Hall, Adam B.; Coy, Stephen L.; Kafle, Amol; Glick, James; Nazarov, Erkinjon

    2013-01-01

    A miniature, planar, differential ion mobility spectrometer (DMS) was interfaced to an LCQ classic ion trap to conduct selective ion filtration prior to mass analysis in order to extend the dynamic range of the trap. Space charge effects are known to limit the functional ion storage capacity of ion trap mass analyzers and this, in turn, can affect the quality of the mass spectral data generated. This problem is further exacerbated in the analysis of mixtures where the indiscriminate introduction of matrix ions results in premature trap saturation with non-targeted species, thereby reducing the number of parent ions that may be used to conduct MS/MS experiments for quantitation or other diagnostic studies. We show that conducting differential mobility-based separations prior to mass analysis allows the isolation of targeted analytes from electrosprayed mixtures preventing the indiscriminate introduction of matrix ions and premature trap saturation with analytically unrelated species. Coupling these two analytical techniques is shown to enhance the detection of a targeted drug metabolite from a biological matrix. In its capacity as a selective ion filter, the DMS can improve the analytical performance of analyzers such as quadrupole (3-D or linear) and ion cyclotron resonance (FT-ICR) ion traps that depend on ion accumulation. PMID:23797861

  18. Traveling Wave Ion Mobility Mass Spectrometry and Ab Initio Calculations of Phosphoric Acid Clusters

    NASA Astrophysics Data System (ADS)

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH] z+ or [(H3PO4)n - zH] z- , with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

  19. Traveling wave ion mobility mass spectrometry and ab initio calculations of phosphoric acid clusters.

    PubMed

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH](z+) or [(H3PO4)n - zH](z-), with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

  20. Studies of peptide a- and b-type fragment ions using stable isotope labeling and integrated ion mobility/tandem mass spectrometry.

    PubMed

    Riba Garcia, Isabel; Giles, Kevin; Bateman, Robert H; Gaskell, Simon J

    2008-12-01

    The structures of peptide a- and b-type fragment ions were studied using synthetic peptides including a set of isomeric peptides, differing in the sequence location of an alanine residue labeled with (15)N and uniformly with (13)C. The pattern of isotope labeling of second-generation fragment ions derived via a(n) and b(n) ions (where n = 4 or 5) suggested that these intermediates existed in part as macrocyclic structures, where alternative sites of ring opening gave rise to different linear forms whose simple cleavage might give rise to the observed final products. Similar conclusions were derived from combined ion mobility/tandem MS analyses where different fragmentation patterns were observed for isomeric a- or b-type ions that display different ion mobilities. These analyses were facilitated by a new approach to the processing of ion mobility/tandem MS data, from which distinct and separate product ion spectra are derived from ions that are incompletely separated by ion mobility. Finally, an example is provided of evidence for a macrocyclic structure for b(n) ions where n = 8 or 9.

  1. Lifetimes and stabilities of familiar explosives molecular adduct complexes during ion mobility measurements

    PubMed Central

    McKenzie, Alan; DeBord, John Daniel; Ridgeway, Mark; Park, Melvin; Eiceman, Gary; Fernandez-Lima, Francisco

    2015-01-01

    Trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) was utilized for the separation and identification of familiar explosives in complex mixtures. For the first time, molecular adduct complex lifetimes, relative stability, binding energies and candidate structures are reported for familiar explosives. Experimental and theoretical results showed that the adduct size and reactivity, complex binding energy and the explosive structure tailors the stability of the molecular adduct complex. TIMS flexibility to adapt the mobility separation as a function of the molecular adduct complex stability (i.e., short or long IMS experiments / low or high IMS resolution) permits targeted measurements of explosives in complex mixtures with higher confidence levels. PMID:26153567

  2. Ion Beam Layer Separation of Cadmium Zinc Telluride

    SciTech Connect

    Bhattacharya, Rabi S.; He, P.; Xu, Y.; Goorsky, M.

    2008-11-03

    We have investigated the approach of ion induced layer separation process for layer splitting from Cadmium Zinc Telluride (CZT) bulk single crystal and transferring and bonding the separated layers with Silicon (Si) wafers. Layer separation experiments have been carried out at UES using 1 MeV H{sup +} ions from the high energy accelerator (1.7 MV Tandetron). Ion dose and annealing temperature for complete separation of 1 cmx1 cm size layers have been optimized. Bonding of CZT with Si was accomplished using various IR transmitting chalcogenide glasses. Cracking of separated CZT films was occurring for chalcogenide glass bonded films. Optimization of thermal treatment has led to the minimization of such cracks. Detailed characterizations of the separated films will be presented.

  3. Mass spectrometric characterization of a high-field asymmetric waveform ion mobility spectrometer

    NASA Astrophysics Data System (ADS)

    Purves, Randy W.; Guevremont, Roger; Day, Stephen; Pipich, Charles W.; Matyjaszczyk, Matthew S.

    1998-12-01

    Ion mobility spectrometry (IMS) has become an important method for the detection of many compounds because of its high sensitivity and amenability to miniaturization for field-portable monitoring; applications include detection of narcotics, explosives, and chemical warfare agents. High-field asymmetric waveform ion mobility spectrometry (FAIMS) differs from IMS in that the electric fields are applied using a high-frequency periodic asymmetric waveform, rather than a dc voltage. Furthermore, in FAIMS the compounds are separated by the difference in the mobility of ions at high electric field relative to low field, rather than by compound to compound differences in mobility at low electric field (IMS). We report here the first cylindrical-geometry-FAIMS interface with mass spectrometry (FAIMS-MS) and the MS identification of the peaks observed in a FAIMS compensation voltage (CV) spectrum. Using both an electrometer-based-FAIMS (FAIMS-E) and FAIMS-MS, several variables that affect the sensitivity of ion detection were examined for two (polarity reversed) asymmetric waveforms (modes 1 and 2) each of which yields a unique spectrum. An increase in the dispersion voltage (DV) was found to improve the sensitivity and separation observed in the FAIMS CV spectrum. This increase in sensitivity and the unexpected dissimilarity in modes 1 and 2 suggest that atmospheric pressure ion focusing is occurring in the FAIMS analyzer. The sensitivity and peak locations in the CV spectra were affected by temperature, gas flow rates, operating pressure, and analyte concentration.

  4. Increasing Confidence of LC-MS Identifications by Utilizing Ion Mobility Spectrometry

    SciTech Connect

    Crowell, Kevin L.; Baker, Erin Shammel; Payne, Samuel H.; Ibrahim, Yehia M.; Monroe, Matthew E.; Slysz, Gordon W.; Lamarche, Brian L.; Petyuk, Vladislav A.; Piehowski, Paul D.; Danielson, William F.; Anderson, Gordon A.; Smith, Richard D.

    2013-09-05

    Ion mobility spectrometry in conjunction with liquid chromatography separations and mass spectrometry offers a range of new possibilities for analyzing complex biological samples. To fully utilize the information obtained from these three measurement dimensions, informatics tools based on the accurate mass and time tag methodology were modified to incorporate ion mobility spectrometry drift times for peptides observed in human serum. A reference human serum database was created using 12,139 peptides, tracking the monoisotopic mass, liquid chromatography normalized elution time, and ion mobility spectrometry drift time(s) for each peptide. We demonstrate that the use of three dimensions for peak matching during the peptide identification process resulted in increased numbers of identifications and lower false discovery rates relative to the use of only the mass and normalized elution time dimensions.

  5. Method of multiplexed analysis using ion mobility spectrometer

    DOEpatents

    Belov, Mikhail E.; Smith, Richard D.

    2009-06-02

    A method for analyzing analytes from a sample introduced into a Spectrometer by generating a pseudo random sequence of a modulation bins, organizing each modulation bin as a series of submodulation bins, thereby forming an extended pseudo random sequence of submodulation bins, releasing the analytes in a series of analyte packets into a Spectrometer, thereby generating an unknown original ion signal vector, detecting the analytes at a detector, and characterizing the sample using the plurality of analyte signal subvectors. The method is advantageously applied to an Ion Mobility Spectrometer, and an Ion Mobility Spectrometer interfaced with a Time of Flight Mass Spectrometer.

  6. GlycoMob: an ion mobility-mass spectrometry collision cross section database for glycomics.

    PubMed

    Struwe, Weston B; Pagel, Kevin; Benesch, Justin L P; Harvey, David J; Campbell, Matthew P

    2016-06-01

    Ion mobility mass spectrometry (IM-MS) is a promising analytical technique for glycomics that separates glycan ions based on their collision cross section (CCS) and provides glycan precursor and fragment masses. It has been shown that isomeric oligosaccharide species can be separated by IM and identified on basis of their CCS and fragmentation. These results indicate that adding CCSs information for glycans and glycan fragments to searchable databases and analysis pipelines will increase identification confidence and accuracy. We have developed a freely accessible database, GlycoMob ( http://www.glycomob.org ), containing over 900 CCSs values of glycans, oligosaccharide standards and their fragments that will be continually updated. We have measured the absolute CCSs of calibration standards, biologically derived and synthetic N-glycans ionized with various adducts in positive and negative mode or as protonated (positive ion) and deprotonated (negative ion) ions. PMID:26314736

  7. Control of Chemical Effects in the Separation Process of a Differential Mobility / Mass Spectrometer System

    PubMed Central

    Schneider, Bradley B.; Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.

    2013-01-01

    Differential mobility spectrometry (DMS) separates ions on the basis of the difference in their migration rates under high versus low electric fields. Several models describing the physical nature of this field mobility dependence have been proposed but emerging as a dominant effect is the clusterization model sometimes referred to as the dynamic cluster-decluster model. DMS resolution and peak capacity is strongly influenced by the addition of modifiers which results in the formation and dissociation of clusters. This process increases selectivity due to the unique chemical interactions that occur between an ion and neutral gas phase molecules. It is thus imperative to bring the parameters influencing the chemical interactions under control and find ways to exploit them in order to improve the analytical utility of the device. In this paper we describe three important areas that need consideration in order to stabilize and capitalize on the chemical processes that dominate a DMS separation. The first involves means of controlling the dynamic equilibrium of the clustering reactions with high concentrations of specific reagents. The second area involves a means to deal with the unwanted heterogeneous cluster ion populations emitted from the electrospray ionization process that degrade resolution and sensitivity. The third involves fine control of parameters that affect the fundamental collision processes, temperature and pressure. PMID:20065515

  8. Control of chemical effects in the separation process of a differential mobility mass spectrometer system.

    PubMed

    Schneider, Bradley B; Covey, Thomas R; Coy, Stephen L; Krylov, Evgeny V; Nazarov, Erkinjon G

    2010-01-01

    Differential mobility spectrometry (DMS) separates ions on the basis of the difference in their migration rates under high versus low electric fields. Several models describing the physical nature of this field mobility dependence have been proposed but emerging as a dominant effect is the clusterization model sometimes referred to as the dynamic cluster-decluster model. DMS resolution and peak capacity is strongly influenced by the addition of modifiers which results in the formation and dissociation of clusters. This process increases selectivity due to the unique chemical interactions that occur between an ion and neutral gas-phase molecules. It is thus imperative to bring the parameters influencing the chemical interactions under control and find ways to exploit them in order to improve the analytical utility of the device. In this paper, we describe three important areas that need consideration in order to stabilize and capitalize on the chemical processes that dominate a DMS separation. The first involves means of controlling the dynamic equilibrium of the clustering reactions with high concentrations of specific reagents. The second area involves a means to deal with the unwanted heterogeneous cluster ion populations emitted from the electrospray ionization process that degrade resolution and sensitivity. The third involves fine control of parameters that affect the fundamental collision processes, temperature and pressure.

  9. Evaluation of Ion Mobility-Mass Spectrometry for Comparative Analysis of Monoclonal Antibodies

    NASA Astrophysics Data System (ADS)

    Ferguson, Carly N.; Gucinski-Ruth, Ashley C.

    2016-05-01

    Analytical techniques capable of detecting changes in structure are necessary to monitor the quality of monoclonal antibody drug products. Ion mobility mass spectrometry offers an advanced mode of characterization of protein higher order structure. In this work, we evaluated the reproducibility of ion mobility mass spectrometry measurements and mobiligrams, as well as the suitability of this approach to differentiate between and/or characterize different monoclonal antibody drug products. Four mobiligram-derived metrics were identified to be reproducible across a multi-day window of analysis. These metrics were further applied to comparative studies of monoclonal antibody drug products representing different IgG subclasses, manufacturers, and lots. These comparisons resulted in some differences, based on the four metrics derived from ion mobility mass spectrometry mobiligrams. The use of collision-induced unfolding resulted in more observed differences. Use of summed charge state datasets and the analysis of metrics beyond drift time allowed for a more comprehensive comparative study between different monoclonal antibody drug products. Ion mobility mass spectrometry enabled detection of differences between monoclonal antibodies with the same target protein but different production techniques, as well as products with different targets. These differences were not always detectable by traditional collision cross section studies. Ion mobility mass spectrometry, and the added separation capability of collision-induced unfolding, was highly reproducible and remains a promising technique for advanced analytical characterization of protein therapeutics.

  10. Micro-machined planar field asymmetric ion mobility spectrometer as a gas chromatographic detector

    NASA Technical Reports Server (NTRS)

    Eiceman, G. A.; Nazarov, E. G.; Miller, R. A.; Krylov, E. V.; Zapata, A. M.

    2002-01-01

    A planar high field asymmetric waveform ion mobility spectrometer (PFAIMS) with a micro-machined drift tube was characterized as a detector for capillary gas chromatography. The performance of the PFAIMS was compared directly to that of a flame ionization detector (FID) for the separation of a ketone mixture from butanone to decanone. Effluent from the column was continuously sampled by the detector and mobility scans could be obtained throughout the chromatographic analysis providing chemical inforrmation in mobility scans orthogonal to retention time. Limits of detection were approximately I ng for measurement of positive ions and were comparable or slightly better than those for the FID. Direct comparison of calibration curves for the FAIMS and the FID was possible over four orders of magnitude with a semi-log plot. The concentration dependence of the PFAIMS mobility scans showed the dependence between ion intensity and ion clustering, evident in other mobility spectrometers and atmospheric pressure ionization technologies. Ions were identified using mass spectrometry as the protonated monomer and the proton bound dimer of the ketones. Residence time for column effluent in the PFAIMS was calculated as approximately 1 ms and a 36% increase in extra-column broadening versus the FID occurred with the PFAIMS.

  11. Detection of gunpowder stabilizers with ion mobility spectrometry.

    PubMed

    West, C; Baron, G; Minet, J-J

    2007-03-01

    This study is the first reported ion mobility detection of ethyl centralite and diphenylamine (DPA) smokeless gunpowder stabilizers, together with the nitroso and nitro derivatives of diphenylamine. First, the applicability of the ion mobility spectrometry (IMS) for the substances of interest was determined. The existence of numerous peaks, both in positive and negative modes, clearly demonstrates the success of these experiments. All mono and di-nitro derivatives of DPA tested were detected with this method. Unfortunately, many of the ions generated were not accurately identified. However, reduced mobility constants representative of each ion generated under defined operating conditions could be used for purpose of compound identification. The method was then successfully tested on real gunpowder samples. By the use of IMS, we managed to establish a rapid, simple and sensitive screening method for the detection and identification of smokeless gunpowder organic components.

  12. Ion Exchange Separation of the Oxidation State of Vanadium.

    ERIC Educational Resources Information Center

    Cornelius, Richard

    1980-01-01

    Describes an experiment that emphasizes the discrete nature of the different oxidation states of vanadium by the separation of ammonium metavanadate into all four species by ion exchange chromatography. (CS)

  13. Shift reagents in ion mobility spectrometry: the effect of the number of interaction sites, size and interaction energies on the mobilities of valinol and ethanolamine.

    PubMed

    Fernández-Maestre, Roberto; Meza-Morelos, Dairo; Wu, Ching

    2016-05-01

    Overlapping peaks interfere in ion mobility spectrometry (IMS), but they are separated introducing mobility shift reagents (SR) in the buffer gas forming adducts with different collision cross-sections (size). IMS separations using SR depend on the ion mobility shifts which are governed by adduct's size and interaction energies (stabilities). Mobility shifts of valinol and ethanolamine ions were measured by electrospray-ionization ion mobility-mass spectrometry (MS). Methyl-chloro propionate (M) was used as SR; 2-butanol (B) and nitrobenzene (N) were used for comparison. Density functional theory was used for calculations. B produced the smallest mobility shifts because of its small size. M and N have two strong interaction sites (oxygen atoms) and similar molecular mass, and they should produce similar shifts. For both ethanolamine and valinol ions, stabilities were larger for N adducts than those of M. With ethanolamine, M produced a 68% shift, large compared to that using N, 61%, because M has a third weak interaction site on the chlorine atom and, therefore, M has more interaction possibilities than N. This third site overrode the oxygen atoms' interaction energy that favored the adduction of ethanolamine with N over that with M. On the contrary, with valinol mobility shifts were larger with N than with M (21 vs 18%) because interaction energy favored even more adduction of valinol with N than with M; that is, the interaction energy difference between adducts of valinol with M and N was larger than that between those adducts with ethanolamine, and the third M interaction could not override this larger difference. Mobility shifts were explained based on the number of SR's interaction sites, size of ions and SR, and SR-ion interaction energies. This is the first time that the number of interaction sites is used to explain mobility shifts in SR-assisted IMS. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Ion-molecule clustering in differential mobility spectrometry: lessons learned from tetraalkylammonium cations and their isomers.

    PubMed

    Campbell, J Larry; Zhu, Mabel; Hopkins, W Scott

    2014-09-01

    Differential mobility spectrometry (DMS) can distinguish ions based upon the differences in their high- and low-field ion mobilities as they experience the asymmetric waveform applied to the DMS cell. These mobilities are known to be influenced by the ions' structure, m/z, and charge distribution (i.e., resonance structures) within the ions themselves, as well as by the gas-phase environment of the DMS cell. While these associations have been developed over time through empirical observations, the exact role of ion structures or their interactions with clustering molecules remains generally unknown. In this study, that relationship is explored by observing the DMS behaviors of a series of tetraalkylammonium ions as a function of their structures and the gas-phase environment of the DMS cell. To support the DMS experiments, the basin-hopping search strategy was employed to identify candidate cluster structures for density functional theory treatment. More than a million cluster structures distributed across 72 different ion-molecule cluster systems were sampled to determine global minimum structures and cluster binding energies. This joint computational and experimental approach suggests that cluster geometry, in particular ion-molecule intermolecular separation, plays a critical role in DMS. PMID:25001379

  15. Ion-molecule clustering in differential mobility spectrometry: lessons learned from tetraalkylammonium cations and their isomers.

    PubMed

    Campbell, J Larry; Zhu, Mabel; Hopkins, W Scott

    2014-09-01

    Differential mobility spectrometry (DMS) can distinguish ions based upon the differences in their high- and low-field ion mobilities as they experience the asymmetric waveform applied to the DMS cell. These mobilities are known to be influenced by the ions' structure, m/z, and charge distribution (i.e., resonance structures) within the ions themselves, as well as by the gas-phase environment of the DMS cell. While these associations have been developed over time through empirical observations, the exact role of ion structures or their interactions with clustering molecules remains generally unknown. In this study, that relationship is explored by observing the DMS behaviors of a series of tetraalkylammonium ions as a function of their structures and the gas-phase environment of the DMS cell. To support the DMS experiments, the basin-hopping search strategy was employed to identify candidate cluster structures for density functional theory treatment. More than a million cluster structures distributed across 72 different ion-molecule cluster systems were sampled to determine global minimum structures and cluster binding energies. This joint computational and experimental approach suggests that cluster geometry, in particular ion-molecule intermolecular separation, plays a critical role in DMS.

  16. Tandem ion mobility spectrometry coupled to laser excitation

    SciTech Connect

    Simon, Anne-Laure; Choi, Chang Min; Clavier, Christian; Barbaire, Marc; Maurelli, Jacques; Dagany, Xavier; MacAleese, Luke; Dugourd, Philippe; Chirot, Fabien

    2015-09-15

    This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collision is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source.

  17. Tandem ion mobility spectrometry coupled to laser excitation.

    PubMed

    Simon, Anne-Laure; Chirot, Fabien; Choi, Chang Min; Clavier, Christian; Barbaire, Marc; Maurelli, Jacques; Dagany, Xavier; MacAleese, Luke; Dugourd, Philippe

    2015-09-01

    This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collision is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source.

  18. Realizing synchronous energy harvesting and ion separation with graphene oxide membranes.

    PubMed

    Sun, Pengzhan; Zheng, Feng; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wu, Dehai; Zhu, Hongwei

    2014-01-01

    A synchronous ion separation and electricity generation process has been developed using G-O membranes. In addition to the size effect proposed prevsiouly, the separation of ions can be attributed to the different interactions between ions and G-O membranes; the generation of electricity is due to the confinement of G-O membranes, and the mobility difference of ions. Efficient energy transduction has been achieved with G-O membranes, converting magnetic, thermal and osmotic energy to electricity, distinguishing this material from other commercial semi-permeable membranes. Our study indicated that G-O membranes could find potential applications in the purification of wastewater, while producing electricity simultaneously. With G-O membranes, industrial magnetic leakage and waste heat could also be used to produce electricity, affording a superior approach for energy recovery.

  19. Realizing synchronous energy harvesting and ion separation with graphene oxide membranes.

    PubMed

    Sun, Pengzhan; Zheng, Feng; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wu, Dehai; Zhu, Hongwei

    2014-01-01

    A synchronous ion separation and electricity generation process has been developed using G-O membranes. In addition to the size effect proposed prevsiouly, the separation of ions can be attributed to the different interactions between ions and G-O membranes; the generation of electricity is due to the confinement of G-O membranes, and the mobility difference of ions. Efficient energy transduction has been achieved with G-O membranes, converting magnetic, thermal and osmotic energy to electricity, distinguishing this material from other commercial semi-permeable membranes. Our study indicated that G-O membranes could find potential applications in the purification of wastewater, while producing electricity simultaneously. With G-O membranes, industrial magnetic leakage and waste heat could also be used to produce electricity, affording a superior approach for energy recovery. PMID:24984782

  20. Realizing Synchronous Energy Harvesting and Ion Separation with Graphene Oxide Membranes

    NASA Astrophysics Data System (ADS)

    Sun, Pengzhan; Zheng, Feng; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wu, Dehai; Zhu, Hongwei

    2014-07-01

    A synchronous ion separation and electricity generation process has been developed using G-O membranes. In addition to the size effect proposed prevsiouly, the separation of ions can be attributed to the different interactions between ions and G-O membranes; the generation of electricity is due to the confinement of G-O membranes, and the mobility difference of ions. Efficient energy transduction has been achieved with G-O membranes, converting magnetic, thermal and osmotic energy to electricity, distinguishing this material from other commercial semi-permeable membranes. Our study indicated that G-O membranes could find potential applications in the purification of wastewater, while producing electricity simultaneously. With G-O membranes, industrial magnetic leakage and waste heat could also be used to produce electricity, affording a superior approach for energy recovery.

  1. Mineral Separation in a CELSS by Ion-exchange Chromatography

    NASA Technical Reports Server (NTRS)

    Ballou, E. V.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

    1982-01-01

    Operational parameters pertinent to ion exchange chromatography separation were identified. The experiments were performed with 9 mm diameter ion exchange columns and conventional column accessories. The cation separation beds were packed with AG 50W-X2 strong acid cation exchange resin in H(+) form and 200-400 dry mesh particle size. The stripper beds used in some experiments were packed with AG 1-XB strong base cation exchange resin in OH(-) form and 200-400 dry mesh particle size.

  2. On-tissue protein identification and imaging by MALDI-ion mobility mass spectrometry.

    PubMed

    Stauber, Jonathan; MacAleese, Luke; Franck, Julien; Claude, Emmanuelle; Snel, Marten; Kaletas, Basak Kükrer; Wiel, Ingrid M V D; Wisztorski, Maxence; Fournier, Isabelle; Heeren, Ron M A

    2010-03-01

    MALDI imaging mass spectrometry (MALDI-IMS) has become a powerful tool for the detection and localization of drugs, proteins, and lipids on-tissue. Nevertheless, this approach can only perform identification of low mass molecules as lipids, pharmaceuticals, and peptides. In this article, a combination of approaches for the detection and imaging of proteins and their identification directly on-tissue is described after tryptic digestion. Enzymatic digestion protocols for different kinds of tissues--formalin fixed paraffin embedded (FFPE) and frozen tissues--are combined with MALDI-ion mobility mass spectrometry (IM-MS). This combination enables localization and identification of proteins via their related digested peptides. In a number of cases, ion mobility separates isobaric ions that cannot be identified by conventional MALDI time-of-flight (TOF) mass spectrometry. The amount of detected peaks per measurement increases (versus conventional MALDI-TOF), which enables mass and time selected ion images and the identification of separated ions. These experiments demonstrate the feasibility of direct proteins identification by ion-mobility-TOF IMS from tissue. The tissue digestion combined with MALDI-IM-TOF-IMS approach allows a proteomics "bottom-up" strategy with different kinds of tissue samples, especially FFPE tissues conserved for a long time in hospital sample banks. The combination of IM with IMS marks the development of IMS approaches as real proteomic tools, which brings new perspectives to biological studies.

  3. Ion mobility spectrometry of hydrazine, monomethylhydrazine, and ammonia in air with 5-nonanone reagent gas

    NASA Technical Reports Server (NTRS)

    Eiceman, G. A.; Salazar, M. R.; Rodriguez, M. R.; Limero, T. F.; Beck, S. W.; Cross, J. H.; Young, R.; James, J. T.

    1993-01-01

    Hydrazine (HZ) and monomethylhydrazine (MMH) in air were monitored continuously using a hand-held ion mobility spectrometer equipped with membrane inlet, 63Ni ion source, acetone reagent gas, and ambient temperature drift tube. Response characteristics included detection limit, 6 ppb; linear range, 10-600 ppb; saturated response, >2 ppm; and stable response after 15-30 min. Ammonia interfered in hydrazines detection through a product ion with the same drift time as that for MMH and HZ. Acetone reagent gas was replaced with 5-nonanone to alter drift times of product ions and separate ammonia from MMH and HZ. Patterns in mobility spectra, ion identifications from mass spectra, and fragmentation cross-sections from collisional-induced dissociations suggest that drift times are governed by ion-cluster equilibria in the drift region of the mobility spectrometer. Practical aspects including calibration, stability, and reproducibility are reported from the use of a hand-held mobility spectrometer on the space shuttle Atlantis during mission STS-37.

  4. Ion mobility spectrometry reveals duplex DNA dissociation intermediates.

    PubMed

    Burmistrova, Anastasia; Gabelica, Valérie; Duwez, Anne-Sophie; De Pauw, Edwin

    2013-11-01

    Electrospray ionization (ESI) soft desolvation is widely used to investigate fragile species such as nucleic acids. Tandem mass spectrometry (MS/MS) gives access to the gas phase energetics of the intermolecular interactions in the absence of solvent, by following the dissociation of mass-selected ions. Ion mobility mass spectrometry (IMS) provides indications on the tridimensional oligonucleotide structure by attributing a collision cross section (CCS) to the studied ion. Electrosprayed duplexes longer than eight bases pairs retain their helical structure in a solvent-free environment. However, the question of conformational changes under activation in MS/MS studies remains open. The objective of this study is to probe binding energetics and characterize the unfolding steps occurring prior to oligonucleotide duplex dissociation. Comparing the evolution of CCS with collision energy and breakdown curves, we characterize dissociation pathways involved in CID-activated DNA duplex separation into single strands, and we demonstrate here the existence of stable dissociation intermediates. At fixed duplex length, dissociation pathways were found to depend on the percentage of GC base pairs and on their position in the duplex. Our results show that pure GC sequences undergo a gradual compaction until reaching the dissociation intermediate: A-helix. Mixed AT-GC sequences were found to present at least two conformers: a classic B-helix and an extended structure where the GC tract is a B-helix and the AT tract(s) fray. The dissociation in single strands takes place from both conformers when the AT base pairs are enclosed between two GC tracts or only from the extended conformer when the AT tract is situated at the end(s) of the sequence.

  5. Ion Mobility Spectrometer / Mass Spectrometer (IMS-MS).

    SciTech Connect

    Hunka, Deborah E; Austin, Daniel

    2005-10-01

    The use of Ion Mobility Spectrometry (IMS)in the Detection of Contraband Sandia researchers use ion mobility spectrometers for trace chemical detection and analysis in a variety of projects and applications. Products developed in recent years based on IMS-technology include explosives detection personnel portals, the Material Area Access (MAA) checkpoint of the future, an explosives detection vehicle portal, hand-held detection systems such as the Hound and Hound II (all 6400), micro-IMS sensors (1700), ordnance detection (2500), and Fourier Transform IMS technology (8700). The emphasis to date has been on explosives detection, but the detection of chemical agents has also been pursued (8100 and 6400).Combining Ion Mobility Spectrometry (IMS) with Mass Spectrometry (MS)The IMS-MS combination overcomes several limitations present in simple IMS systems. Ion mobility alone is insufficient to identify an unknown chemical agent. Collision cross section, upon which mobility is based, is not sufficiently unique or predictable a priori to be able to make a confident peak assignment unless the compounds present are already identified. Molecular mass, on the other hand, is much more readily interpreted and related to compounds. For a given compound, the molecular mass can be determined using a pocket calculator (or in one's head) while a reasonable value of the cross-section might require hours of computation time. Thus a mass spectrum provides chemical specificity and identity not accessible in the mobility spectrum alone. In addition, several advanced mass spectrometric methods, such as tandem MS, have been extensively developed for the purpose of molecular identification. With an appropriate mass spectrometer connected to an ion mobility spectrometer, these advanced identification methods become available, providing greater characterization capability.3 AcronymsIMSion mobility spectrometryMAAMaterial Access AreaMSmass spectrometryoaTOForthogonal acceleration time

  6. Detection of Biological Materials Using Ion Mobility Spectroscopy

    SciTech Connect

    Rodacy, P.J.; Sterling, J.P.; Butler, M.A.

    1999-03-01

    Traditionally, Ion Mobility Spectroscopy has been used to examine ions of relatively low molecular weight and high ion mobility. In recent years, however, biomolecules such as bradykinin, cytochrome c, bovine pancreatic trypsin inhibitor (BPTI), apomyoglobin, and lysozyme, have been successfully analyzed, but studies of whole bio-organisms have not been performed. In this study an attempt was made to detect and measure the mobility of two bacteriophages, {lambda}-phage and MS2 using electrospray methods to inject the viruses into the ion mobility spectrometer. Using data from Yeh, et al., which makes a comparison between the diameter of non-biologic particles and the specific particle mobility, the particle mobility for the MS2 virus was estimated to be 10{sup {minus}2} cm{sup 2}/volt-sec. From this mobility the drift time of these particles in our spectrometer was calculated to be approximately 65 msec. The particle mobility for the {lambda}-phage virus was estimated to be 10{sup {minus}3} cm{sup 2}/volt-sec. which would result in a drift time of 0.7 sec. Spectra showing the presence of a viral peak at the expected drift time were not observed. However, changes in the reactant ion peak that could be directly attributed to the presence of the viruses were observed. Virus clustering, excessive collisions, and the electrospray injection method limited the performance of this IMS. However, we believe that an instrument specifically designed to analyze such bioagents and utilizing other injection and ionization methods will succeed in directly detecting viruses and bacteria.

  7. Separation of platinum group metal ions by Donnan dialysis

    SciTech Connect

    Brajter, K.; Slonawska, K.; Cox, J.A.

    1985-10-01

    Separations of metal ions on the basis of Donnan dialysis across anion-exchange membranes should be possible if the receiver electrolyte composition favors the formation of selected anionic complexes of the sample metal ions. Moreover, such a separation has the possibility of being better suited from some applications than batch or column experiments with anion-exchange resins. The above hypothesis are tested on the platinum-group metal ions, Pt(IV), Rh(III), Pd(II), Ir(III), and Ir(IV). 13 references, 4 tables.

  8. Characterization of triacetone triperoxide by ion mobility spectrometry and mass spectrometry following atmospheric pressure chemical ionization

    SciTech Connect

    Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.

    2011-04-28

    The atmospheric pressure chemical ionization of triacetone triperoxide (TATP) with subsequent separation and detection by ion mobility spectrometry has been studied. Positive ionization with hydronium reactant ions produced only fragments of the TATP molecule, with m/z 91 ion being the most predominant species. Ionization with ammonium reactant ions produced a molecular adduct at m/z 240. The reduced mobility value of this ion was constant at 1.36 cm{sup 2}V{sup -1}s{sup -1} across the temperature range from 60 to 140 C. The stability of this ion was temperature dependent and did not exist at temperatures above 140 C, where only fragment ions were observed. The introduction of ammonia vapors with TATP resulted in the formation of m/z 58 ion. As the concentration of ammonia increased, this smaller ion appeared to dominate the spectra and the TATP-ammonium adduct decreased in intensity. The ion at m/z 58 has been noted by several research groups upon using ammonia reagents in chemical ionization, but the identity was unknown. Evidence presented here supports the formation of protonated 2-propanimine. A proposed mechanism involves the addition of ammonia to the TATP-ammonium adduct followed by an elimination reaction. A similar mechanism involving the chemical ionization of acetone with excess ammonia also showed the formation of m/z 58 ion. TATP vapors from a solid sample were detected with a hand-held ion mobility spectrometer operated at room temperature. The TATP-ammonium molecular adduct was observed in the presence of ammonia and TATP vapors with this spectrometer.

  9. Characterization of triacetone triperoxide by ion mobility spectrometry and mass spectrometry following atmospheric pressure chemical ionization.

    PubMed

    Ewing, Robert G; Waltman, Melanie J; Atkinson, David A

    2011-06-15

    The atmospheric pressure chemical ionization of triacetone triperoxide (TATP) with subsequent separation and detection by ion mobility spectrometry has been studied. Positive ionization with hydronium reactant ions produced only fragments of the TATP molecule, with m/z 91 ion being the most predominant species. Ionization with ammonium reactant ions produced a molecular adduct at m/z 240. The reduced mobility value of this ion was constant at 1.36 cm(2)V(-1)s(-1) across the temperature range from 60 to 140 °C. The stability of this ion was temperature dependent and did not exist at temperatures above 140 °C, where only fragment ions were observed. The introduction of ammonia vapors with TATP resulted in the formation of m/z 58 ion. As the concentration of ammonia increased, this smaller ion appeared to dominate the spectra and the TATP-ammonium adduct decreased in intensity. The ion at m/z 58 has been noted by several research groups upon using ammonia reagents in chemical ionization, but the identity was unknown. Evidence presented here supports the formation of protonated 2-propanimine. A proposed mechanism involves the addition of ammonia to the TATP-ammonium adduct followed by an elimination reaction. A similar mechanism involving the chemical ionization of acetone with excess ammonia also showed the formation of m/z 58 ion. TATP vapors from a solid sample were detected with a hand-held ion mobility spectrometer operated at room temperature. The TATP-ammonium molecular adduct was observed in the presence of ammonia and TATP vapors with this spectrometer. PMID:21524145

  10. Separation of organic ion exchange resins from sludge -- engineering study

    SciTech Connect

    Duncan, J.B.

    1998-08-25

    This engineering study evaluates the use of physical separation technologies to separate organic ion exchange resin from KE Basin sludge prior to nitric acid dissolution. This separation is necessitate to prevent nitration of the organics in the acid dissolver. The technologies under consideration are: screening, sedimentation, elutriation. The recommended approach is to first screen the Sludge and resin 300 microns then subject the 300 microns plus material to elutriation.

  11. Separation of ions in acidic solution by capillary electrophoresis

    SciTech Connect

    Thornton, M.

    1997-10-08

    Capillary electrophoresis (CE) is an effective method for separating ionic species according to differences in their electrophoretic mobilities. CE separations of amino acids by direct detection are difficult due to their similar electrophoretic mobilities and low absorbances. However, native amino acids can be separated by CE as cations at a low pH by adding an alkanesulfonic acid to the electrolyte carrier which imparts selectivity to the system. Derivatization is unnecessary when direct UV detection is used at 185 nm. Simultaneous speciation of metal cations such as vanadium (IV) and vanadium (V) can easily be performed without complexation prior to analysis. An indirect UV detection scheme for acidic conditions was also developed using guanidine as the background carrier electrolyte (BCE) for the indirect detection of metal cations. Three chapters have been removed for separate processing. This report contains introductory material, references, and general conclusions. 80 refs.

  12. Ion mobility spectrometer / mass spectrometer (IMS-MS).

    SciTech Connect

    Hunka Deborah Elaine; Austin, Daniel E.

    2005-07-01

    The use of Ion Mobility Spectrometry (IMS) in the Detection of Contraband Sandia researchers use ion mobility spectrometers for trace chemical detection and analysis in a variety of projects and applications. Products developed in recent years based on IMS-technology include explosives detection personnel portals, the Material Area Access (MAA) checkpoint of the future, an explosives detection vehicle portal, hand-held detection systems such as the Hound and Hound II (all 6400), micro-IMS sensors (1700), ordnance detection (2500), and Fourier Transform IMS technology (8700). The emphasis to date has been on explosives detection, but the detection of chemical agents has also been pursued (8100 and 6400). Combining Ion Mobility Spectrometry (IMS) with Mass Spectrometry (MS) is described. The IMS-MS combination overcomes several limitations present in simple IMS systems. Ion mobility alone is insufficient to identify an unknown chemical agent. Collision cross section, upon which mobility is based, is not sufficiently unique or predictable a priori to be able to make a confident peak assignment unless the compounds present are already identified. Molecular mass, on the other hand, is much more readily interpreted and related to compounds. For a given compound, the molecular mass can be determined using a pocket calculator (or in one's head) while a reasonable value of the cross-section might require hours of computation time. Thus a mass spectrum provides chemical specificity and identity not accessible in the mobility spectrum alone. In addition, several advanced mass spectrometric methods, such as tandem MS, have been extensively developed for the purpose of molecular identification. With an appropriate mass spectrometer connected to an ion mobility spectrometer, these advanced identification methods become available, providing greater characterization capability.

  13. Entropic Electrokinetics: Recirculation, Particle Separation, and Negative Mobility

    NASA Astrophysics Data System (ADS)

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J. Miguel

    2014-09-01

    We show that when particles are suspended in an electrolyte confined between corrugated charged surfaces, electrokinetic flows lead to a new set of phenomena such as particle separation, mixing for low-Reynolds micro- and nanometric devices, and negative mobility. Our analysis shows that such phenomena arise, for incompressible fluids, due to the interplay between the electrostatic double layer and the corrugated geometrical confinement and that they are magnified when the width of the channel is comparable to the Debye length. Our characterization allows us to understand the physical origin of such phenomena, therefore, shedding light on their possible relevance in a wide variety of situations ranging from nano- and microfluidic devices to biological systems.

  14. Entropic electrokinetics: recirculation, particle separation, and negative mobility.

    PubMed

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J Miguel

    2014-09-19

    We show that when particles are suspended in an electrolyte confined between corrugated charged surfaces, electrokinetic flows lead to a new set of phenomena such as particle separation, mixing for low-Reynolds micro- and nanometric devices, and negative mobility. Our analysis shows that such phenomena arise, for incompressible fluids, due to the interplay between the electrostatic double layer and the corrugated geometrical confinement and that they are magnified when the width of the channel is comparable to the Debye length. Our characterization allows us to understand the physical origin of such phenomena, therefore, shedding light on their possible relevance in a wide variety of situations ranging from nano- and microfluidic devices to biological systems. PMID:25279646

  15. Augmenting Ion Trap Mass Spectrometers Using a Frequency Modulated Drift Tube Ion Mobility Spectrometer.

    PubMed

    Morrison, Kelsey A; Siems, William F; Clowers, Brian H

    2016-03-15

    Historically, high pressure ion mobility drift tubes have suffered from low ion duty cycles and this problem is magnified when such instrumentation is coupled with ion trap mass spectrometers. To significantly alleviate these issues, we outline the result from coupling an atmospheric pressure, dual-gate drift tube ion mobility spectrometer (IMS) to a linear ion trap mass spectrometer (LIT-MS) via modulation of the ion beam with a linear frequency chirp. The time-domain ion current, once Fourier transformed, reveals a standard ion mobility drift spectrum that corresponds to the standard mode of mobility analysis. By multiplexing the ion beam, it is possible to successfully obtain drift time spectra for an assortment of simple peptide and protein mixtures using an LIT-MS while showing improved signal intensity versus the more common signal averaging technique. Explored here are the effects of maximum injection time, solution concentration, total experiment time, and frequency swept on signal-to-noise ratios (SNRs) and resolving power. Increased inject time, concentration, and experiment time all generally led to an improvement in SNR, while a greater frequency swept increases the resolving power at the expense of SNR. Overall, chirp multiplexing of a dual-gate IMS system coupled to an LIT-MS improves ion transmission, lowers analyte detection limits, and improves spectral quality. PMID:26854901

  16. Ion current detector for high pressure ion sources for monitoring separations

    DOEpatents

    Smith, Richard D.; Wahl, Jon H.; Hofstadler, Steven A.

    1996-01-01

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source.

  17. Ion current detector for high pressure ion sources for monitoring separations

    DOEpatents

    Smith, R.D.; Wahl, J.H.; Hofstadler, S.A.

    1996-08-13

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source. 7 figs.

  18. Dividing to unveil protein microheterogeneities: traveling wave ion mobility study.

    PubMed

    Halgand, F; Habchi, Johnny; Cravello, Laetitia; Martinho, Marlène; Guigliarelli, Bruno; Longhi, Sonia

    2011-10-01

    Overexpression of a protein in a foreign host is often the only route toward an exhaustive characterization, especially when purification from the natural source(s) is hardly achievable. The key issue in these studies relies on quality control of the purified recombinant protein to precisely determining its identity as well as any undesirable microheterogeneities. While standard proteomics approaches preclude unbiased search for modifications, the optional technique of top-down tandem mass spectrometry (MSMS) requires the use of highly accurate and highly resolved experiments to reveal subtle sequence modifications. In the present study, the top-down MSMS approach combined with traveling wave ion mobility (TWIM) separation was evaluated for its ability to achieve high sequence coverage and to reveal subtle microheterogeneities that were hitherto only accessible with Fourier-transform ion cyclotron resonance-MS instruments. The power of this approach is herein illustrated in an in-depth analysis of both the wild type and K496C variant of the recombinant X domain (XD; aa's 459-507) of the measles virus phosphoprotein expressed in Escherichia coli . Using top-down MSMS combined with TWIM, we show that XD samples occasionally exhibit a microheterogeneity that could not be anticipated from the nucleotide sequence of the encoding constructs and that likely reflects a genetic drift, neutral or not, occurring during expression. In addition, a 1-oxyl-2,2,5,5-tetramethyl-δ3-pyrroline-3-methyl methanethiosulfonate nitroxide probe that was grafted onto the K496C XD variant was shown to undergo oxidation and/or protonation in the electrospray ionization source, leading to artifactual mass increases.

  19. Improving ion mobility measurement sensitivity by utilizing helium in an ion funnel trap.

    PubMed

    Ibrahim, Yehia M; Garimella, Sandilya V B; Tolmachev, Aleksey V; Baker, Erin S; Smith, Richard D

    2014-06-01

    Ion mobility instruments that utilize nitrogen as buffer gas are often preceded by an ion trap and accumulation region that also uses nitrogen, and for different inert gases, no significant effects upon performance are expected for ion mobility spectrometry (IMS) of larger ions. However, we have observed significantly improved performance for an ion funnel trap upon adding helium; the signal intensities for higher m/z species were improved by more than an order of magnitude compared to using pure nitrogen. The effect of helium upon IMS resolving power was also studied by introducing a He/N2 gas mixture into the drift cell, and in some cases, a slight improvement was observed compared to pure N2. The improvement in signal can be largely attributed to faster and more efficient ion ejection into the drift tube from the ion funnel trap.

  20. New, high-efficiency ion trap mobility detection system for narcotics and explosives

    NASA Astrophysics Data System (ADS)

    McGann, William J.; Bradley, V.; Borsody, A.; Lepine, S.

    1994-10-01

    A new patented Ion Trap Mobility Spectrometer (ITMS) design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electric field driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC and LSD are reported.

  1. New high-efficiency ion trap mobility detection system for narcotics and explosives

    NASA Astrophysics Data System (ADS)

    McGann, William J.; Jenkins, Anthony; Ribiero, K.; Napoli, J.

    1994-03-01

    A new patented ion trap mobility spectrometer design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electrical-field-driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC, and LSD are reported.

  2. Chelation and foam separation of metal ions from solutions

    SciTech Connect

    Carleson, T.E.; Moussavi, M.

    1988-08-01

    An experimental study was conducted on the chelation and foam separation of trace amounts of cadmium, zinc, and lead from their water solutions. The chelation agents ethylenediaminetetraacetate (sodium salt), sodium diethyldithiocarbamate, and citric acid were used with sodium dodecylsulfate (SDS) as a foam-producing agent. The chelation agents did not produce metal complexes that were very surface active. The foam-producing agent produced metal ion complexes that were surface active and resulted in appreciable separation of the metal ions. The use of 100 ppm SDS resulted in separation of 90% of the zinc ions from solution containing 2 to 20 ppm zinc. At concentrations below and above this, the removal efficiency dropped significantly.

  3. Resolution of Ion Mobility Spectra for the Detection of Hazardous Substances in Real Sampling Conditions

    SciTech Connect

    Montoliu, I.; Kalms, A.; Pardo, A.; Pomareda, V.; Marco, S.; Goebel, J.; Kessler, M.; Mueller, G.

    2009-05-23

    This work presents the possibilities offered by a blind source separation method such Multivariate Curve Resolution- Alternating Least Squares (MCR-ALS) in the analysis of Ion Mobility Spectra (IMS). Two security applications are analyzed in this context: the detection of TNT both in synthetic and real samples. Results obtained show the possibilities offered by the direct analysis of the drift time spectra when an appropriate resolution method is used.

  4. Cryogenic molecular separation system for radioactive 11C ion acceleration

    NASA Astrophysics Data System (ADS)

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.

    2015-12-01

    A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  5. Preorganized and Immobilized Ligands for Metal Ion Separations

    SciTech Connect

    Paine, Robert T.

    2015-07-01

    The research project, in the period 2003-2015, was focused on the discovery of fundamental new principles in f-element ion coordination chemistry and the application of the new knowledge to the development of advanced detection/separations reagents and methods for these ions. The findings relate to the Nation's efforts to safely and efficiently process nuclear materials. In addition, the project provided training for young scientists needed to maintain the Nation's preeminence in nuclear science.

  6. COLUMBIC OXIDE ADSORPTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM IONS

    DOEpatents

    Beaton, R.H.

    1959-07-14

    A process is described for separating plutonium ions from a solution of neutron irradiated uranium in which columbic oxide is used as an adsorbert. According to the invention the plutonium ion is selectively adsorbed by Passing a solution containing the plutonium in a valence state not higher than 4 through a porous bed or column of granules of hydrated columbic oxide. The adsorbed plutonium is then desorbed by elution with 3 N nitric acid.

  7. LABORATORY DETECTION OF PLASTICS IN SEEDCOTTON WITH ION MOBILITY SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The US cotton industry wants to increase market share and value by supplying pure cotton. Removing contamination requires developing a means to detect plastics in seedcotton. This study was conducted to determine if Ion Mobility Spectrometry (IMS) could be used to find small amounts of plastic in ...

  8. Transient Ion-Pair Separations for Electrospray Mass Spectrometry.

    PubMed

    Liu, Hanghui; Lam, Lily; Chi, Bert; Kadjo, Akinde F; Dasgupta, Purnendu K

    2016-02-16

    We report a novel ion-pair chromatography (IPC) approach for liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS), where the eluent does not contain any ion-pairing reagent (IPR). The IPR is injected on the column, much like the sample, and moves down the column. Significant amounts of a high retention factor IPR is injected, resulting in a transient but reproducible regional coating that progresses along the column. The sample is injected after a brief interval. The sample components interact with the IPR coated region during their passage; the chosen eluent gradient elutes the analytes of interest into the mass spectrometer before the IPR. Following analyte elution, the gradient is steeply raised, the IPR is washed out, and the effluent is sent to waste via a diverter valve until it is fully removed. As the nature of the analyte retention continuously changes along the column and with time, we call this transient ion-pair separation (TIPS). As the IPR never enters the MS, TIPS addresses two major drawbacks of IPC for ESI-MS: it avoids both ion suppression and ion source contamination. The potential of the generic approach for other modes of separation is discussed. An illustrative separation of two small inorganic ions, iodate and nitrate, is demonstrated on a reverse phase column by a transient prior injection of hexadecyltrimethylammonium chloride as IPR. PMID:26765166

  9. Statistical characterization of air ion mobility spectra at Tahkuse Observatory: Classification of air ions

    NASA Astrophysics Data System (ADS)

    Hõrrak, U.; Salm, J.; Tammet, H.

    2000-04-01

    A database of 8615 hourly averaged air ion mobility spectra in the range of 0.00041-3.2 cm2 V-1 s-1 was measured at Tahkuse Observatory, Estonia, during 14 months in 1993-1994. The average mobility spectrum over the whole period shows distinct peaks of small and large ions. Intermediate ions with mobilities of 0.034-0.5 cm2 V-1 s-1 are of low concentration of about 50 cm-3 in the average spectrum. They experience occasional bursts of up to about 900 cm-3 during 6-10 hours at daytime. The number of burst events recorded during 14 months was 101, with maximum frequency in spring and minimum frequency in winter. Physically, large and intermediate ions can be called aerosol ions, and small ions can be called cluster ions. The principal component analysis was applied to detect the structure of an air ion mobility spectrum. As a result, the mobility spectrum in the range of 0.00041-3.2 cm2 V-1 s-1 (diameters of 0.36-79 nm) was divided into five classes: small cluster, big cluster, intermediate, light large, and heavy large ions. The boundaries between the classes are 1.3 cm2 V-1 s-1 (diameter of 0.85 nm), 0.5 cm2 V-1 s-1 (1.6 nm), 0.034 cm2 V-1 s-1 (7.4 nm), and 0.0042 cm2 V-1 s-1 (22 nm). The five principal components that are closely correlated with the respective ion classes explain 92% of total variance. The classification of aerosol ions is in accord with the three-modal structure of the size spectrum of submicron aerosol particles.

  10. Anion-exchange separations of metal ions in thiocyanate media.

    PubMed

    Fritz, J S; Kaminski, E E

    1971-05-01

    The analytical potential of a weak-base macroreticular anion-exchange resin for the quantitative separation of metal ions in thiocyanate media is investigated and demonstrated. Distribution data are given for the sorption of some 25 metal ions from aqueous mixtures of potassium thiocyanate (1.0M or less) and 0.5M hydrochloric acid. The magnitude of the distribution data suggests many possible separations, some of which were quantitatively performed by procedures which are fast, simple and require only mild conditions. Representative separations are removal of traces of iron(III) and copper(II) from water samples prior to the determination of water hardness (calcium and magnesium), separation of nickel(II) from vanadium(IV) and the separation of thorium(IV) from titanium(IV). Some multicomponent separations are the separation of rare earths(III) and thorium(IV) from scandium(III) and the separation of rare earths(III) from iron(III) and uranium(VI). PMID:18960914

  11. LC-IMS-MS Feature Finder. Detecting Multidimensional Liquid Chromatography, Ion Mobility, and Mass Spectrometry Features in Complex Datasets

    SciTech Connect

    Crowell, Kevin L.; Slysz, Gordon W.; Baker, Erin Shammel; Lamarche, Brian L.; Monroe, Matthew E.; Ibrahim, Yehia M.; Payne, Samuel H.; Anderson, Gordon A.; Smith, Richard D.

    2013-09-05

    We introduce a command line software application LC-IMS-MS Feature Finder that searches for molecular ion signatures in multidimensional liquid chromatography-ion mobility spectrometry-mass spectrometry (LC-IMS-MS) data by clustering deisotoped peaks with similar monoisotopic mass, charge state, LC elution time, and ion mobility drift time values. The software application includes an algorithm for detecting and quantifying co-eluting chemical species, including species that exist in multiple conformations that may have been separated in the IMS dimension.

  12. Fast Screening of Polycyclic Aromatic Hydrocarbons using Trapped Ion Mobility Spectrometry - Mass Spectrometry

    PubMed Central

    Castellanos, A.; Benigni, P.; Hernandez, D. R.; DeBord, J. D.; Ridgeway, M. E.; Park, M. A.

    2014-01-01

    In the present paper, we showed the advantages of trapped ion mobility spectrometry coupled too mass spectrometry (TIMS-MS) combined with theoretical calculations for fast identification (millisecond timescale) of polycyclic aromatic hydrocarbons (PAH) compounds from complex mixtures. Accurate PAH collision cross sections (CCS, in nitrogen as a bath gas) are reported for the most commonly encountered PAH compounds and the ability to separate PAH geometric isomers is shown for three isobaric pairs with mobility resolution exceeding 150 (3–5 times higher than conventional IMS devices). Theoretical candidate structures (optimized at the DFT/B3LYP level) are proposed for the most commonly encountered PAH compounds showing good agreement with the experimental CCS values (<5%). The potential of TIMS-MS for the separation and identification of PAH compounds from complex mixtures without the need of lengthy pre-separation steps is illustrated for the case of a complex soil mixture. PMID:25558291

  13. Utilizing Ion-Mobility Data to Estimate Molecular Masses

    NASA Technical Reports Server (NTRS)

    Duong, Tuan; Kanik, Isik

    2008-01-01

    A method is being developed for utilizing readings of an ion-mobility spectrometer (IMS) to estimate molecular masses of ions that have passed through the spectrometer. The method involves the use of (1) some feature-based descriptors of structures of molecules of interest and (2) reduced ion mobilities calculated from IMS readings as inputs to (3) a neural network. This development is part of a larger effort to enable the use of IMSs as relatively inexpensive, robust, lightweight instruments to identify, via molecular masses, individual compounds or groups of compounds (especially organic compounds) that may be present in specific environments or samples. Potential applications include detection of organic molecules as signs of life on remote planets, modeling and detection of biochemicals of interest in the pharmaceutical and agricultural industries, and detection of chemical and biological hazards in industrial, homeland-security, and industrial settings.

  14. Control of Ion Distortion in Field Asymmetric Waveform Ion Mobility Spectrometry via Variation of Dispersion Field and Gas Temperature

    SciTech Connect

    Robinson, Errol W.; Shvartsburg, Alexandre A.; Tang, Keqi; Smith, Richard D.

    2008-10-01

    Field asymmetric waveform ion mobility spectrometry (FAIMS) has emerged as an analytical tool of broad utility, especially in conjunction with mass spectrometry. Of particular promise is the use of FAIMS and 2-D ion mobility methods that combine it with conventional IMS to resolve and characterize protein and other macromolecular conformers. However, FAIMS operation requires high electric fields and ions are inevitably heated by above-thermal collisions with buffer gas molecules. This may induce ion isomerization and dissociation that distort separation properties determined by FAIMS and subsequent stages and/or reduce instrumental sensitivity. As FAIMS employs a periodic waveform, the ion temperature can be characterized at the maximum or average field intensity (E). Which method is most applicable to temperature sensitive ions, such as protein ions, has been debated. Here we address this issue by measuring the unfolding of compact ubiquitin ion geometries as a function of waveform amplitude (dispersion field, ED) and gas temperature, T. The field heating is quantified by matching the dependences of structural transitions on ED and T. Increasing ED from 12 to 16 or from 16 to 20 kV/cm is equivalent to heating the (N2) gas by ~15 - 25 oC. The magnitude of field heating for any E can be calculated using the two-temperature theory, and raising ED by 4 kV/cm augments heating by ~15 - 30 oC for maximum and ~4 - 8 oC for average E in the FAIMS cycle. Hence, isomerization of ions in FAIMS appears to be governed by the maximum internal temperature at waveform peaks.

  15. Separation of ions in nanofluidic channels with combined pressure-driven and electro-osmotic flow.

    PubMed

    Gillespie, Dirk; Pennathur, Sumita

    2013-03-01

    Separation of ionic species with the same electrophoretic mobility but different valence in electrolyte systems can occur within nanometer-scale channels with finite electrical double layers (EDLs). This is because EDL thicknesses are a significant fraction of slit height in such channels and can create transverse analyte concentration profiles that allow for unique separation modalities when combined with axial fluid flow. Previous work has shown such separation to occur using either pressure-driven flow or electro-osmotic flow separately. Here, we develop a Poisson-Boltzmann model to compare the separation of such ions using the combination of both pressure-driven and electro-osmotic flow. Applying a pressure gradient in the opposite direction of electro-osmotic flow can allow for zero or infinite retention of analyte species, which we investigate using three different wall boundary conditions. Furthermore, we determine conditions in fused silica nanochannels with which to generate optimal separation between two analytes of different charge but the same mobility. We also give simple rules of thumb to achieve the best separation efficacy in nanochannel systems.

  16. Arrival time distributions of product ions reveal isomeric ratio of deprotonated molecules in ion mobility-mass spectrometry of hyaluronan-derived oligosaccharides.

    PubMed

    Hermannová, Martina; Iordache, Andreea-Maria; Slováková, Kristína; Havlíček, Vladimír; Pelantová, Helena; Lemr, Karel

    2015-06-01

    Hyaluronic acid is a naturally occurring linear polysaccharide with substantial medical potential. In this work, discrimination of tyramine-based hyaluronan derivatives was accessed by ion mobility-mass spectrometry of deprotonated molecules and nuclear magnetic resonance spectroscopy. As the product ion mass spectra did not allow for direct isomer discrimination in mixture, the reductive labeling of oligosaccharides as well as stable isotope labeling was performed. The ion mobility separation of parent ions together with the characteristic fragmentation for reduced isomers providing unique product ions allowed us to identify isomers present in a mixture and determine their mutual isomeric ratio. The determination used simple recalculation of arrival time distribution areas of unique ions to areas of deprotonated molecules. Mass spectrometry data were confirmed by nuclear magnetic resonance spectroscopy.

  17. Ultrasensitive Identification of Localization Variants of Modified Peptides Using Ion Mobility Spectrometry

    SciTech Connect

    Ibrahim, Yehia M.; Shvartsburg, Alexandre A.; Smith, Richard D.; Belov, Mikhail E.

    2011-05-28

    Localization of the modification sites on peptides is challenging, particularly when multiple modifications or mixtures of localization isomers (variants) are involved. Such variants commonly coelute in liquid chromatography and may be undistinguishable in tandem mass spectrometry (MS/MS) for lack of unique fragments. Here, we have resolved the variants of singly and doubly phosphorylated peptides employing drift tube ion mobility spectrometry (IMS) coupled to time-of-flight mass spectrometry. Even with a moderate IMS resolving power of ~80, substantial separation was achieved for both 2+ and 3+ ions normally generated by electrospray ionization, including for the variant indistinguishable by MS/MS. Variants often exhibit a distribution of 3-D conformers, which can be adjusted for optimum IMS separation by prior field heating of ions in a funnel trap. The peak assignments were confirmed using MS/MS after IMS separation, but known species could be identified using just the ion mobility "tag". Avoiding the MS/MS step lowers the detection limit of localization variants to <100 attomoles, an order of magnitude better than provided by electron transfer dissociation in an Orbitrap MS.

  18. Separation of Carbon Dioxide from Flue Gas Using Ion Pumping

    SciTech Connect

    Aines, R; Bourcier, W L; Johnson, M R

    2006-04-21

    We are developing a new way of separating carbon dioxide from flue gas based on ionic pumping of carbonate ions dissolved in water. Instead of relying on large temperature or pressure changes to remove carbon dioxide from solvent used to absorb it from flue gas, the ion pump increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, which can be removed from the downstream side of the ion pump as a nearly pure gas. This novel approach to increasing the concentration of the extracted gas permits new approaches to treating flue gas. The slightly basic water used as the extraction medium is impervious to trace acid gases that destroy existing solvents, and no pre-separation is necessary. The simple, robust nature of the process lends itself to small separation plants. Although the energy cost of the ion pump is significant, we anticipate that it will be compete favorably with the current 35% energy penalty of chemical stripping systems in use at power plants. There is the distinct possibility that this simple method could be significantly more efficient than existing processes.

  19. Ion chromatography for the separation of heparin and structurally related glycoaminoglycans: A review.

    PubMed

    Fasciano, Jennifer M; Danielson, Neil D

    2016-03-01

    The global crisis resulting from adulterated heparin in late 2007 and early 2008 revived the importance of analytical techniques for the purity analysis of heparin products. The utilization of ion chromatography techniques for the separation, detection, and structural determination of heparin and structurally related glycoaminoglycans, including their corresponding oligosaccharides, has become increasingly important. This review summarizes the primary HPLC approaches, particularly strong anion exchange, weak ion exchange, and reversed-phase ion-pair, used for heparin purity analysis as well as structural characterization. Strong anion exchange HPLC has been studied most extensively and currently offers the best separation of crude heparin and heparin-like compounds. Weak anion exchange HPLC has been shown to provide shorter analysis times with lower salt concentrations in the mobile phase but is not as widely developed for the separation of all glycoaminoglycans of interest. Reversed-phase ion-pair HPLC offers fast and effective separations of oligosaccharides derived from glycoaminoglycans that can be coupled to mass spectrometry for structural analysis. However, this method generally does not provide sufficient retention of intact glycoaminoglycans.

  20. Determination of boron in silicates after ion exchange separation

    USGS Publications Warehouse

    Kramer, H.

    1955-01-01

    Existing methods for the determination of boron in silicates are not entirely satisfactory. Separation as the methyl ester is lengthy and frequently erratic. An accurate and rapid method applicable to glass, mineral, ore, and water samples uses ion exchange to remove interfering cations, and boron is determined titrimetrically in the presence of mannitol, using a pH meter to indicate the end point.

  1. Separation of americium from curium by oxidation and ion exchange.

    PubMed

    Burns, Jonathan D; Shehee, Thomas C; Clearfield, Abraham; Hobbs, David T

    2012-08-21

    Nuclear energy has the potential to be a clean alternative to fossil fuels, but in order for it to play a major role in the US, many questions about the back end of the fuel cycle must be addressed. One of these questions is the difficult separation of americium from curium. Here, we report the oxidation of Am in two systems, perchloric acid and nitric acid and the affect of changing the acid has on the oxidation. K(d) values were observed and a direct separation factor was calculated and was seen to be as high as 20 for four metal(IV) pillared phosphate phosphonate inorganic organic hybrid ion exchange materials. These ion exchangers are characterized by very low selectivity for cations with low charge but extremely high uptake of ions of high charge.

  2. Multiplexed Ion Mobility Spectrometry - Orthogonal Time-Of-Flight Mass Spectrometry

    SciTech Connect

    Belov, Mikhail E.; Buschbach, Michael A.; Prior, David C.; Tang, Keqi; Smith, Richard D.

    2007-03-15

    Ion mobility spectrometry (IMS) coupled to orthogonal time-of-flight mass spectrometry (TOF) has shown significant promise for the characterization of complex biological mixtures. The enormous complexity of biological samples (e.g. from proteomics) and the need for both biological and technical analysis replicates imposes major challenges for multidimensional separation platforms in regard to both sensitivity and sample throughput. A major potential attraction of the IMS-TOF MS platform is separation speeds exceeding that of conventional condensed-phase separations by orders of magnitude. Known limitations of the IMS-TOF MS platforms that presently mitigate this attraction include the need for extensive signal averaging due to factors that include significant ion losses in the IMS-TOF interface and an ion utilization efficiency of less than ~1% with continuous ion sources (e.g. ESI). We have developed a new multiplexed ESI-IMS-TOF mass spectrometer that enables lossless ion transmission through the IMS-TOF as well as a utilization efficiency of >50% for ions from the ESI source. Initial results with a mixture of peptides show a ~10-fold increase in signal-to-noise ratio with the multiplexed approach compared to a signal averaging approach, with no reduction in either IMS or TOF MS resolution.

  3. High Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

    DOEpatents

    Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

    2005-11-22

    A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

  4. The Role of Mobile Surface Ions in Nanomaterial Formation

    NASA Astrophysics Data System (ADS)

    Kendall, T. A.; Martin, S. T.

    2007-12-01

    Biogenic and abiotic nanomaterial formation alters the electrical layout of mineral surfaces. Complex dielectric and surface diffusional regimes that affect water sorption, metal co-precipitation, and possibly cell attachment are created. Polarization force microscopy measurements reveal the importance of mobile, surface associated ions in nanomaterial formation, particularly in subaerial conditions. Mass and charge transport between nanostructures can occur via two-dimensional diffusion of surface ions within mono- to multi-layer water. Further, nanostructure stability depends on epitaxy with the underlying substrate. On calcite under humid air, we observe the formation of a 1 to 1.5 nm thick, hydrated calcium carbonate film. This nanophase, which is typically protein- stabilized as an intermediate within biomineralization schema, is instead stabilized by the calcite 104 surface. Moreover, nanostructure dissolution on rhodochrosite is initiated by the accumulation of hydrated, edge- associated ions, most likely representing partially mobilized, positively-charged film material. We connect these molecular-level observations to large-scale, biogeophysical measurements that hold promise of remotely sensing bacteria in the subsurface (e.g., induced polarization (IP)). Here, mobile surface ion diffusion at the cell- mineral interface and biogenic nanomaterial formation are identified as key contributors to the poorly understood IP signature of bacteria in porous media.

  5. Biomedical applications of ion mobility-enhanced data-independent acquisition-based label-free quantitative proteomics.

    PubMed

    Distler, Ute; Kuharev, Jörg; Tenzer, Stefan

    2014-12-01

    Mass spectrometry-based proteomics greatly benefited from recent improvements in instrument performance and the development of bioinformatics solutions facilitating the high-throughput quantification of proteins in complex biological samples. In addition to quantification approaches using stable isotope labeling, label-free quantification has emerged as the method of choice for many laboratories. Over the last years, data-independent acquisition approaches have gained increasing popularity. The integration of ion mobility separation into commercial instruments enabled researchers to achieve deep proteome coverage from limiting sample amounts. Additionally, ion mobility provides a new dimension of separation for the quantitative assessment of complex proteomes, facilitating precise label-free quantification even of highly complex samples. The present work provides a thorough overview of the combination of ion mobility and data-independent acquisition-based label-free quantification LC-MS and its applications in biomedical research.

  6. Mesoporous Cladophora cellulose separators for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Pan, Ruijun; Cheung, Ocean; Wang, Zhaohui; Tammela, Petter; Huo, Jinxing; Lindh, Jonas; Edström, Kristina; Strømme, Maria; Nyholm, Leif

    2016-07-01

    Much effort is currently made to develop inexpensive and renewable materials which can replace the polyolefin microporous separators conventionally used in contemporary lithium-ion batteries. In the present work, it is demonstrated that mesoporous Cladophora cellulose (CC) separators constitute very promising alternatives based on their high crystallinity, good thermal stability and straightforward manufacturing. The CC separators, which are fabricated using an undemanding paper-making like process involving vacuum filtration, have a typical thickness of about 35 μm, an average pore size of about 20 nm, a Young's modulus of 5.9 GPa and also exhibit an ionic conductivity of 0.4 mS cm-1 after soaking with 1 M LiPF6 EC: DEC (1/1, v/v) electrolyte. The CC separators are demonstrated to be thermally stable at 150 °C and electrochemically inert in the potential range between 0 and 5 V vs. Li+/Li. A LiFePO4/Li cell containing a CC separator showed good cycling stability with 99.5% discharge capacity retention after 50 cycles at a rate of 0.2 C. These results indicate that the renewable CC separators are well-suited for use in high-performance lithium-ion batteries.

  7. Developments in ion mobility spectrometry-mass spectrometry.

    PubMed

    Collins, D C; Lee, M L

    2002-01-01

    Ion mobility spectrometry (IMS) has been used for over 30 years as a sensitive detector of organic compounds. The following is a brief review of IMS and its principles with an emphasis on its usage when coupled to mass spectrometry. Since its inception, IMS has been interfaced with quadrupole, time-of-flight, and Fourier-transform ion cyclotron resonance mass spectrometry. These hybrid instruments have been employed for the analysis of a variety of target analytes, including biomolecules, explosives, chemical warfare degradation products, and illicit drugs. PMID:11939214

  8. Micro faraday-element array detector for ion mobility spectroscopy

    DOEpatents

    Gresham, Christopher A.; Rodacy, Phillip J.; Denton, M. Bonner; Sperline, Roger

    2004-10-26

    An ion mobility spectrometer includes a drift tube having a collecting surface covering a collecting area at one end of the tube. The surface comprises a plurality of closely spaced conductive elements on a non-conductive substrate, each conductive element being electrically insulated from each other element. A plurality of capacitive transimpedance amplifiers (CTIA) adjacent the collecting surface are electrically connected to the plurality of elements, so charge from an ion striking an element is transferred to the capacitor of the connected CTIA. A controller counts the charge on the capacitors over a period of time.

  9. Structured back gates for high-mobility two-dimensional electron systems using oxygen ion implantation

    NASA Astrophysics Data System (ADS)

    Berl, M.; Tiemann, L.; Dietsche, W.; Karl, H.; Wegscheider, W.

    2016-03-01

    We present a reliable method to obtain patterned back gates compatible with high mobility molecular beam epitaxy via local oxygen ion implantation that suppresses the conductivity of an 80 nm thick silicon doped GaAs epilayer. Our technique was optimized to circumvent several constraints of other gating and implantation methods. The ion-implanted surface remains atomically flat which allows unperturbed epitaxial overgrowth. We demonstrate the practical application of this gating technique by using magneto-transport spectroscopy on a two-dimensional electron system (2DES) with a mobility exceeding 20 × 106 cm2/V s. The back gate was spatially separated from the Ohmic contacts of the 2DES, thus minimizing the probability for electrical shorts or leakage and permitting simple contacting schemes.

  10. Ion mobility and transport barriers in the tokamak plasmas

    SciTech Connect

    Xiao, H.; Hazeltine, R.D. ); Zhang, Y.Z. ); Valanju, P.M. )

    1993-12-01

    The character of charged particle motion in an axisymmetric toroidal system with a constant radial electric field is investigated both analytically and numerically. Ion radial mobility caused by the combined effects of the radial electric field and charge exchange is found. A simple moment argument in the banana regime matches the simulation results well. Relation of present work and high confinement (H-mode) experiment is also discussed.

  11. Ion mobility and transport barriers in the tokamak plasmas

    SciTech Connect

    Xiao, H.; Hazeltine, R.D.; Valanju, P.M.; Zhang, Y.Z.

    1993-06-01

    The character of charged particle motion in an axisymmetric toroidal system with a constant radial electric field is investigated both analytically and numerically. Ion radial mobility caused by the combined effects of the radial electric field and charge exchange is found. A simple moment argument in the banana regime matches the simulation results well. Relation of present work and high confinement (H-mode) experiment is also discussed.

  12. Compact ExB mass separator for heavy ion beams

    SciTech Connect

    Wada, M.; Hashino, T.; Hirata, F.; Kasuya, T.; Sakamoto, Y.; Nishiura, M.

    2008-02-15

    A compact ExB mass separator that deflects beam by 30 deg. has been designed and built to prove its principle of operation. The main part of the separator is contained in a shielding box of 11 cm long, 9 cm wide, and 1.5 cm high. An electromagnet of 7 cm pole diameter produced variable magnetic field in the mass separation region instead of a couple of permanent magnets which is to be used in the final design. The experimental result agreed well with the theoretical prediction, and larger mass ions is bent with less magnetic field with the aid of the deflection electric field. The reduction in resolving power for mass separation due to the deflection electric field has been investigated experimentally.

  13. Evaluation of ion mobility-mass spectrometry for determining the isomeric heterogeneity of oligosaccharide-alditols derived from bovine submaxillary mucin.

    PubMed

    Li, Hongli; Bendiak, Brad; Kaplan, Kimberly; Davis, Eric; Siems, William F; Hill, Herbert H

    2013-10-15

    Rapid separation and independent analysis of isomeric species are needed for the structural characterization of carbohydrates in glycomics research. Ion mobility-mass spectrometry techniques were used to examine a series of isomeric neutral oligosaccharide-alditols derived from bovine submaxillary mucin. Several analytical techniques were employed: (1) off line separation of the oligosaccharide-alditol mixture by HPLC; (2) direct and rapid evaluation of isomeric heterogeneity of oligosaccharides by electrospray ionization-ion mobility-time of flight mass spectrometry; and (3) mobility-selected MS(2) and MS(3) to evaluate isomeric mobility peaks by dual gate ion mobility-tandem mass spectrometry. Multiple isomeric ion mobility peaks were observed for the majority of oligosaccharide-alditols, which was achieved on the millisecond time scale after LC separation. Fragmentation spectra obtained from the collision-induced dissociation of isomeric precursor ions could be essentially identical, or dramatically different for a given precursor m/z using the dual-gate ion mobility quadrupole ion trap mass spectrometer. This further confirmed the need for rapid physical resolution of isomeric precursor species prior to their tandem mass spectral analysis.

  14. Ultra High-Resolution Electrospray Ionization/Ion Mobility Spectrometer System for In-Situ Detection of Organic Compounds

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Beegle, L. W.; Hill, H. H.

    2001-01-01

    The potential of the high-resolution Electrospray Ionization/Ion Mobility Spectrometry (ESI/IMS) technique as analytical separation tool in analyzing bio-molecular mixtures in the search for the chemical signatures of life is demonstrated. Additional information is contained in the original extended abstract.

  15. Lifetimes and stabilities of familiar explosive molecular adduct complexes during ion mobility measurements.

    PubMed

    McKenzie-Coe, Alan; DeBord, John Daniel; Ridgeway, Mark; Park, Melvin; Eiceman, Gary; Fernandez-Lima, Francisco

    2015-08-21

    Trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) was utilized for the separation and identification of familiar explosives in complex mixtures. For the first time, molecular adduct complex lifetimes, relative stability, binding energies and candidate structures are reported for familiar explosives. Experimental and theoretical results showed that the adduct size and reactivity, complex binding energy and the explosive structure tailor the stability of the molecular adduct complex. The flexibility of TIMS to adapt the mobility separation as a function of the molecular adduct complex stability (i.e., short or long IMS experiments/low or high IMS resolution) permits targeted measurements of explosives in complex mixtures with high confidence levels.

  16. New high-efficiency ion-trap mobility detection system for narcotics

    NASA Astrophysics Data System (ADS)

    McGann, William J.

    1997-02-01

    A new patented Ion Trap Mobility Spectrometer design is presented. Conventional IMS designs typically operate below 0.1 percent efficiency. This is due primarily to electric field driven, sample ion discharge on a shutter grid. Since 99.9 percent of the sample ions generated in the reaction region are lost int his discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an 'ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a 'field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. One application for this new detector is now being developed, a portable, hand-held system with switching capability for the detection of drugs and explosives. Preliminary ion spectra and sensitivity data are presented for cocaine and heroin using a hand sniffer configuration.

  17. High-Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

    DOEpatents

    Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

    2004-11-16

    A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

  18. Mobile ion distribution and anharmonic thermal motion in fast ion conducting Cu/sub 2/S

    SciTech Connect

    Cava, R.J.; Reidinger, F.; Wuensch, B.J.

    1981-01-01

    A unique model was determined for the mobile copper ion disorder in hexagonal Cu/sub 2/S between 120/sup 0/ and 325/sup 0/C via single crystal neutron diffraction. The copper ions partially occupy two sets of three-coordinated sites within the HCP sulfur array and display anharmonic thermal motion. The results suggest that the conductivity is two dimensional in nature.

  19. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    SciTech Connect

    Hobbs, D.; Visser, A.; Bridges, N.

    2011-09-20

    This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

  20. Determination of ammonia in ethylene using ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Cross, J. H.; Limero, T. F.; Lane, J. L.; Wang, F.

    1997-01-01

    A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated.

  1. Dynamic multiplexed analysis method using ion mobility spectrometer

    SciTech Connect

    Belov, Mikhail E

    2010-05-18

    A method for multiplexed analysis using ion mobility spectrometer in which the effectiveness and efficiency of the multiplexed method is optimized by automatically adjusting rates of passage of analyte materials through an IMS drift tube during operation of the system. This automatic adjustment is performed by the IMS instrument itself after determining the appropriate levels of adjustment according to the method of the present invention. In one example, the adjustment of the rates of passage for these materials is determined by quantifying the total number of analyte molecules delivered to the ion trap in a preselected period of time, comparing this number to the charge capacity of the ion trap, selecting a gate opening sequence; and implementing the selected gate opening sequence to obtain a preselected rate of analytes within said IMS drift tube.

  2. Implementation of Dipolar Resonant Excitation Collision Induced Dissociation with Ion Mobility/Time-of-Flight MS

    SciTech Connect

    Webb, Ian K.; Chen, Tsung-Chi; Danielson, William F.; Ibrahim, Yehia M.; Tang, Keqi; Anderson, Gordon A.; Smith, Richard D.

    2014-01-28

    Under and overfragmentation are significant hurdles to the data independent “bottom-up” approach to proteomics. Another challenge to the data independent approach is the convolution of fragments from different peptides that coelute in reverse-phase liquid chromatography/mass spectrometry (RPLC/MS). The ion mobility/collision induced dissociation/time-of flight mass spectrometry (IMS/CID/TOF MS) approach gives drift-time aligned fragment ions that have the same arrival time distributions as precursor ions, greatly aiding in fragment and peptide ion identification. We have modified an IMS/TOF MS platform to allow for resonant excitation CID experiments. Resonant excitation CID leads to highly efficient, mass-resolved fragmentation without additional excitation of product ions, alleviating the overfragmentation problem. The ability to apply resonant waveforms in mobility-resolved windows has been demonstrated with a peptide mixture yielding fragmentation over a range of mass-to-charge (m/z) ratios within a single IMS separation experiment.

  3. Continuous ion exchange separation of zirconium and hafnium

    SciTech Connect

    Begovich, J.M.; Sisson, W.G.

    1981-01-01

    A pressurized continuous annular chromatograph (CAC) has been developed for truly continuous ion exchange preparative separations. This device utilizes a slowly rotating annular bed of sorbent material, fixed multiple feed points, and fixed withdrawal locations. Most of our investigations have been performed with a 28-cm-diam by 60-cm-long CAC, but a larger model has recently been designed and constructed. A detailed study has been made of the separation of copper, nickel, and cobalt components from a simulated carbonate leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Recent studies have investigated the ion exchange separation of zirconium and hafnium from a sulfate feed solution. Nuclear reactor-grade zirconium, containing < 0.01 wt % hafnium, and hafnium, containing < 1% zirconium, have been continuously prepared using cation exchange resin in the pressurized CAC. This device, because of its continuous feed and product withdrawal, its adaptability to largescale operations, and its ability to separate many components, is expected to make chromatography a more competitive process in the industrial sector.

  4. Detecting and Removing Data Artifacts in Hadamard Transform Ion Mobility-Mass Spectrometry Measurements

    DOE PAGESBeta

    Prost, Spencer A.; Crowell, Kevin L.; Baker, Erin Shammel; Ibrahim, Yehia M.; Clowers, Brian H.; Monroe, Matthew E.; Anderson, Gordon A.; Smith, Richard D.; Payne, Samuel H.

    2014-05-06

    Applying Hadamard transform multiplexing to ion mobility separations (IMS) can significantly improve the signal-to-noise ratio and throughput for IMS coupled mass spectrometry (MS) measurements by increasing the ion utilization efficiency. However, it has been determined that both fluctuations in ion intensity as well as spatial shifts in the multiplexed data lower the signal-to-noise ratios and appear as noise in downstream processing of the data. To address this problem, we have developed a novel algorithm that discovers and eliminates data artifacts. The algorithm uses knowledge of the true signal peaks derived from the encoded data and allows for both artifacts andmore » noise to be removed with high confidence, decreasing the likelihood of false identifications in subsequent data processing. The result is that IMS-MS can be applied to increase measurement sensitivity while avoiding artifacts that have previously limited its utility.« less

  5. Detecting and Removing Data Artifacts in Hadamard Transform Ion Mobility-Mass Spectrometry Measurements

    NASA Astrophysics Data System (ADS)

    Prost, Spencer A.; Crowell, Kevin L.; Baker, Erin S.; Ibrahim, Yehia M.; Clowers, Brian H.; Monroe, Matthew E.; Anderson, Gordon A.; Smith, Richard D.; Payne, Samuel H.

    2014-12-01

    Applying Hadamard transform multiplexing to ion mobility separations (IMS) can significantly improve the signal-to-noise ratio and throughput for IMS coupled mass spectrometry (MS) measurements by increasing the ion utilization efficiency. However, it has been determined that fluctuations in ion intensity as well as spatial shifts in the multiplexed data lower the signal-to-noise ratios and appear as noise in downstream processing of the data. To address this problem, we have developed a novel algorithm that discovers and eliminates data artifacts. The algorithm employs an analytical approach to identify and remove artifacts from the data, decreasing the likelihood of false identifications in subsequent data processing. Following application of the algorithm, IMS-MS measurement sensitivity is greatly increased and artifacts that previously limited the utility of applying the Hadamard transform to IMS are avoided. [Figure not available: see fulltext.

  6. Detecting and Removing Data Artifacts in Hadamard Transform Ion Mobility-Mass Spectrometry Measurements

    SciTech Connect

    Prost, Spencer A.; Crowell, Kevin L.; Baker, Erin Shammel; Ibrahim, Yehia M.; Clowers, Brian H.; Monroe, Matthew E.; Anderson, Gordon A.; Smith, Richard D.; Payne, Samuel H.

    2014-05-06

    Applying Hadamard transform multiplexing to ion mobility separations (IMS) can significantly improve the signal-to-noise ratio and throughput for IMS coupled mass spectrometry (MS) measurements by increasing the ion utilization efficiency. However, it has been determined that both fluctuations in ion intensity as well as spatial shifts in the multiplexed data lower the signal-to-noise ratios and appear as noise in downstream processing of the data. To address this problem, we have developed a novel algorithm that discovers and eliminates data artifacts. The algorithm uses knowledge of the true signal peaks derived from the encoded data and allows for both artifacts and noise to be removed with high confidence, decreasing the likelihood of false identifications in subsequent data processing. The result is that IMS-MS can be applied to increase measurement sensitivity while avoiding artifacts that have previously limited its utility.

  7. A compact high resolution ion mobility spectrometer for fast trace gas analysis.

    PubMed

    Kirk, Ansgar T; Allers, Maria; Cochems, Philipp; Langejuergen, Jens; Zimmermann, Stefan

    2013-09-21

    Drift tube ion mobility spectrometers (IMS) are widely used for fast trace gas detection in air, but portable compact systems are typically very limited in their resolving power. Decreasing the initial ion packet width improves the resolution, but is generally associated with a reduced signal-to-noise-ratio (SNR) due to the lower number of ions injected into the drift region. In this paper, we present a refined theory of IMS operation which employs a combined approach for the analysis of the ion drift and the subsequent amplification to predict both the resolution and the SNR of the measured ion current peak. This theoretical analysis shows that the SNR is not a function of the initial ion packet width, meaning that compact drift tube IMS with both very high resolution and extremely low limits of detection can be designed. Based on these implications, an optimized combination of a compact drift tube with a length of just 10 cm and a transimpedance amplifier has been constructed with a resolution of 183 measured for the positive reactant ion peak (RIP(+)), which is sufficient to e.g. separate the RIP(+) from the protonated acetone monomer, even though their drift times only differ by a factor of 1.007. Furthermore, the limits of detection (LODs) for acetone are 180 pptv within 1 s of averaging time and 580 pptv within only 100 ms.

  8. External Second Gate-Fourier Transform Ion Mobility Spectrometry.

    SciTech Connect

    Tarver, Edward E., III

    2005-01-01

    Ion mobility spectrometry (IMS) is recognized as one of the most sensitive and versatile techniques for the detection of trace levels of organic vapors. IMS is widely used for detecting contraband narcotics, explosives, toxic industrial compounds and chemical warfare agents. Increasing threat of terrorist attacks, the proliferation of narcotics, Chemical Weapons Convention treaty verification as well as humanitarian de-mining efforts has mandated that equal importance be placed on the analysis time as well as the quality of the analytical data. (1) IMS is unrivaled when both speed of response and sensitivity has to be considered. (2) With conventional (signal averaging) IMS systems the number of available ions contributing to the measured signal to less than 1%. Furthermore, the signal averaging process incorporates scan-to-scan variations decreasing resolution. With external second gate Fourier Transform ion mobility spectrometry (FT-IMS), the entrance gate frequency is variable and can be altered in conjunction with other data acquisition parameters to increase the spectral resolution. The FT-IMS entrance gate operates with a 50% duty cycle and so affords a 7 to 10-fold increase in sensitivity. Recent data on high explosives are presented to demonstrate the parametric optimization in sensitivity and resolution of our system.

  9. Cryogenic Ion Mobility-Mass Spectrometry: Tracking Ion Structure from Solution to the Gas Phase.

    PubMed

    Servage, Kelly A; Silveira, Joshua A; Fort, Kyle L; Russell, David H

    2016-07-19

    Electrospray ionization (ESI) combined with ion mobility-mass spectrometry (IM-MS) is adding new dimensions, that is, structure and dynamics, to the field of biological mass spectrometry. There is increasing evidence that gas-phase ions produced by ESI can closely resemble their solution-phase structures, but correlating these structures can be complicated owing to the number of competing effects contributing to structural preferences, including both inter- and intramolecular interactions. Ions encounter unique hydration environments during the transition from solution to the gas phase that will likely affect their structure(s), but many of these structural changes will go undetected because ESI-IM-MS analysis is typically performed on solvent-free ions. Cryogenic ion mobility-mass spectrometry (cryo-IM-MS) takes advantage of the freeze-drying capabilities of ESI and a cryogenically cooled IM drift cell (80 K) to preserve extensively solvated ions of the type [M + xH](x+)(H2O)n, where n can vary from zero to several hundred. This affords an experimental approach for tracking the structural evolution of hydrated biomolecules en route to forming solvent-free gas-phase ions. The studies highlighted in this Account illustrate the varying extent to which dehydration can alter ion structure and the overall impact of cryo-IM-MS on structural studies of hydrated biomolecules. Studies of small ions, including protonated water clusters and alkyl diammonium cations, reveal structural transitions associated with the development of the H-bond network of water molecules surrounding the charge carrier(s). For peptide ions, results show that water networks are highly dependent on the charge-carrying species within the cluster. Specifically, hydrated peptide ions containing lysine display specific hydration behavior around the ammonium ion, that is, magic number clusters with enhanced stability, whereas peptides containing arginine do not display specific hydration around the

  10. Demonstrated Potential of Ion Mobility Spectrometry for Detection of Adulterated Perfumes and Plant Speciation

    SciTech Connect

    Clark, Jared Matthew; Daum, Keith Alvin; Kalival, J. H.

    2003-01-01

    This initial study evaluates the use of ion mobility spectrometry (IMS) as a rapid test procedure for potential detection of adulterated perfumes and speciation of plant life. Sample types measured consist of five genuine perfumes, two species of sagebrush, and four species of flowers. Each sample type is treated as a separate classification problem. It is shown that discrimination using principal component analysis with K-nearest neighbors can distinguish one class from another. Discriminatory models generated using principal component regressions are not as effective. Results from this examination are encouraging and represent an initial phase demonstrating that perfumes and plants possess characteristic chemical signatures that can be used for reliable identification.

  11. High-Resolution Differential Ion Mobility Spectrometry of a Protein

    SciTech Connect

    Shvartsburg, Alexandre A.; Smith, Richard D.

    2013-01-17

    Use of elevated electric fields and helium-rich gases has recently enabled differential IMS with resolving power up to R ~ 300. Here we applied that technique to proteins (namely, mass-selected ubiquitin ions), achieving R up to ~80 and separating many previously mixed conformers. While still limited by conformational multiplicity within each observed feature, this resolution is some four times the highest previously reported using either conventional or differential IMS. The capability for fine resolution of protein conformers may open new avenues for variant separation in top-down proteomics.

  12. Electron attachment and ion mobility in hydrocarbons and related systems

    SciTech Connect

    Bakale, G.

    1988-01-01

    During the last two decades, a firm base for the emerging field of liquid state electronics (LSE) has developed through studies of the transport and reaction properties of excess electrons in a variety of liquid-phase systems. Pulse-conductivity techniques were used in many of these studies to measure the mobilities of electrons and ions in pure liquids as well as the rate constants of electron attachment to a wide variety of electron-accepting solutes. Results obtained through such studies have interdisciplinary implications that are described in the discussion that follows which includes examples of the contributions of LSE to physics, chemistry and biology. 42 refs.

  13. Ion mobility mass spectrometry of peptide, protein, and protein complex ions using a radio-frequency confining drift cell.

    PubMed

    Allen, Samuel J; Giles, Kevin; Gilbert, Tony; Bush, Matthew F

    2016-02-01

    Ion mobility mass spectrometry experiments enable the characterization of mass, assembly, and shape of biological molecules and assemblies. Here, a new radio-frequency confining drift cell is characterized and used to measure the mobilities of peptide, protein, and protein complex ions. The new drift cell replaced the traveling-wave ion mobility cell in a Waters Synapt G2 HDMS. Methods for operating the drift cell and determining collision cross section values using this experimental set up are presented within the context of the original instrument control software. Collision cross sections for 349 cations and anions are reported, 155 of which are for ions that have not been characterized previously using ion mobility. The values for the remaining ions are similar to those determined using a previous radio-frequency confining drift cell and drift tubes without radial confinement. Using this device under 2 Torr of helium gas and an optimized drift voltage, denatured and native-like ions exhibited average apparent resolving powers of 14.2 and 16.5, respectively. For ions with high mobility, which are also low in mass, the apparent resolving power is limited by contributions from ion gating. In contrast, the arrival-time distributions of low-mobility, native-like ions are not well explained using only contributions from ion gating and diffusion. For those species, the widths of arrival-time distributions are most consistent with the presence of multiple structures in the gas phase.

  14. MALDI-MS/MS with Traveling Wave Ion Mobility for the Structural Analysis of N-Linked Glycans

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Scarff, Charlotte A.; Crispin, Max; Scanlan, Christopher N.; Bonomelli, Camille; Scrivens, James H.

    2012-11-01

    The preference for singly charged ion formation by MALDI makes it a better choice than electrospray ionization for profiling mixtures of N-glycans. For structural analysis, fragmentation of negative ions often yields more informative spectra than fragmentation of positive ones but such ions are more difficult to produce from neutral glycans under MALDI conditions. This work investigates conditions for the formation of both positive and negative ions by MALDI from N-linked glycans released from glycoproteins and their subsequent MS/MS and ion mobility behaviour. 2,4,6-Trihydroxyacetophenone (THAP) doped with ammonium nitrate was found to give optimal ion yields in negative ion mode. Ammonium chloride or phosphate also yielded prominent adducts but anionic carbohydrates such as sulfated N-glycans tended to ionize preferentially. Carbohydrates adducted with all three adducts (phosphate, chloride, and nitrate) produced good negative ion CID spectra but those adducted with iodide and sulfate did not yield fragment ions although they gave stronger signals. Fragmentation paralleled that seen following electrospray ionization providing superior spectra than could be obtained by PSD on MALDI-TOF instruments or with ion traps. In addition, ion mobility drift times of the adducted glycans and the ability of this technique to separate isomers also mirrored those obtained following ESI sample introduction. Ion mobility also allowed profiles to be obtained from samples whose MALDI spectra showed no evidence of such ions allowing the technique to be used in conditions where sample amounts were limiting. The method was applied to N-glycans released from the recombinant human immunodeficiency virus glycoprotein, gp120.

  15. Wakefield accelerators in the blowout regime with mobile ions

    NASA Astrophysics Data System (ADS)

    Lee, S.; Katsouleas, T.

    1999-07-01

    In the Plasma Wakefield Accelerator a high current drive-beam excites a large wake that can accelerate trailing particles. The wake is created when the space charge of the drive beam displaces plasma electrons. The plasma ions provide the restoring force on the displaced electrons. For symmetric bunches, the peak accelerating gradient is proportional to the current over a pulse length. For example, for a Gaussian bunch with 6nC of charge and bunch length σz≈0.6 mm, a gradient of 1GeV/m can be obtained. For the case of dense (beam density greater than plasma density), narrow (beam spot size σr smaller than c/ωp) beams the plasma response is non-linear and is dominated by the radial blow out of all the plasma electrons. However, such dense beams are strongly focused by the plasma lens effect. As a result they become so dense that ion motion should become important even on the electron plasma frequency time-scale. We will present analytic and 2-D particle-in-cell (PIC) models of wake excitation including mobile ions. The effect of the ion motion on the accelerating and focusing wake and the dynamics of the drive beam are discussed.

  16. Control of the reactant ion chemistry for the analysis of explosives by ion mobility spectroscopy

    SciTech Connect

    Rodacy, P.J.; Ingersoll, D.

    1995-07-01

    Changes in the reactant ion composition in the ion mobility spectrometer (IMS) can result in a change in the ionization processes occurring in the ionization region, ultimately leading to an altered instrumental response for the analyte, and exacerbating the problem of qualitative and quantitative analysis. Some species are very susceptible to changes in reactant ions, while other species are relatively unaffected. These types of behavior are observed for two common explosives, namely, hexahydro-1,3,5-trinitrol,3,5-triazine (RDX) and 1,3,5-trinitrotoluene (TNT), respectively. To control the reactant ion composition, and hence the gas phase chemistry, it is necessary to control the composition of gases present in the ionization region of the IMS. A series of modifications are described for the PCP Phemto-Chem 100 IMS that afford the requisite control. The effectiveness of these modifications for analysis of RDX and TNT are described and contrasted with that observed for the unmodified system.

  17. Resolving Interferences in Negative Mode Ion Mobility Spectrometry Using Selective Reactant Ion Chemistry

    SciTech Connect

    Daum, Keith Alvin; Atkinson, David Alan; Ewing, Robert Gordon; Knighton, W. B.; Grimsrud, E. P

    2001-04-01

    During the investigation of the degradation products of 2,4,6-trinitrotoluene (TNT) using ion mobility spectrometry (IMS), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (DCP) were found to have IMS responses which overlapped those of the TNT degradation products. It was observed that the Cl- reactant ion chemistry, often used for explosives analysis, was not always successful in resolving peak overlap of analytes and interferents. It is shown here that resolution of the analytes and interferences can sometimes be achieved using only air for the formation of reactant ions, at other times through the use of Br- as an alternative to Cl- for producing reactant ions, and also through the promotion of adduct stability by lowering the IMS temperature.

  18. Boric acid as a mobile phase additive for high performance liquid chromatography separation of ribose, arabinose and ribulose.

    PubMed

    De Muynck, Cassandra; Beauprez, Joeri; Soetaert, Wim; Vandamme, Erick J

    2006-01-01

    A new high performance liquid chromatographic (HPLC) method is described for the analysis of ribose, arabinose and ribulose mixtures obtained from (bio)chemical isomerization processes. These processes gain importance since the molecules can be used for the synthesis of antiviral therapeutics. The HPLC method uses boric acid as a mobile phase additive to enhance the separation on an Aminex HPX-87K column. By complexing with boric acid, the carbohydrates become negatively charged, thus elute faster from the column by means of ion exlusion and are separated because the complexation capacity with boric acid differs from one carbohydrate to another. Excellent separation between ribose, ribulose and arabinose was achieved with concentrations between 0.1 and 10 gL(-1) of discrete sugar.

  19. Discrimination of large maltooligosaccharides from isobaric dextran and pullulan using ion mobility mass spectrometry

    PubMed Central

    Rashid, Abdul M; Saalbach, Gerhard; Bornemann, Stephen

    2013-01-01

    RATIONALE Ion mobility mass spectrometry (IMMS) has previously been shown to resolve small isobaric oligosaccharides, but larger alpha-oligoglucans are also abundant in biology and are of industrial importance. If conformational differences between such isomers are retained in the gas phase, IMMS could be used to address questions in biology and industry. METHODS Negative mode electrospray ionization (ESI) travelling-wave IMMS was used to resolve large isobaric α-glucan ions on the basis of their different gas-phase conformations. α,ω-Dicarboxy-terminated polystyrene was used to calibrate the instrument allowing the collision cross-sections (CCSs) of ions to be determined. RESULTS α-1,4-Linked maltooligosaccharides with a degree of polymerisation of up to 35 could be discriminated from α-1,6-linked dextran and α-1,4/1,6-linked pullulan using IMMS. Fragmentation spectra of ions separated by IMMS could also distinguish isomers. Two conformational isomers of maltohexaose were resolvable by IMMS, likely reflecting extended and V6 helical conformations. IMMS was also able to identify a product within a mixture of maltooligosaccharides treated with the potential anti-tuberculosis drug target Mycobacterium tuberculosis GlgB branching enzyme. CONCLUSIONS Biological samples of complex isobaric oligosaccharides can be analysed using IMMS in the negative mode providing facile analyses and high sensitivity without the need for either derivatisation or chromatographic separation. © 2013 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:24338967

  20. Analysis of heterogeneous uptake by nanoparticles via differential mobility analysis-drift tube ion mobility spectrometry.

    PubMed

    Oberreit, Derek R; McMurry, Peter H; Hogan, Christopher J

    2014-04-21

    Improved methods are needed to study sorption of vapor molecules by particles in the gas phase (heterogeneous uptake), which is an important process in both natural and engineered environments. Here, a new measurement system, composed of a differential mobility analyzer (DMA) and drift tube ion mobility spectrometer (DTIMS) in series, is used to examine the heterogeneous uptake of water vapor by 2.85-7.6 nm particles composed of lithium and sodium iodide. The extent of heterogeneous uptake is determined by controlling the relative humidity of the drift region in the DTIMS in the 0-30% range (in air at atmospheric pressure and room temperature), and is quantified via the dimensionless growth factor (GF), i.e. the ratio of the mobility diameter of particles at a prescribed relative humidity relative to their mobility diameter under dry conditions. The precision in GF estimation of the DMA-DTIMS system is shown to be below 0.2%. An analytical equation to calculate the growth factor, based upon predictions of the equilibrium constants for the successive uptake of vapor molecules by particles, is also presented. While the equation is sufficiently general to enable comparison between measured GFs and predictions from any theoretical expression for equilibrium constants, we specifically compare measurements to GF predictions based on the classical Kelvin-Thomson-Raoult (KTR) model for the vapor pressure of a small particle, with consideration of the influence of the ion-dipole potential on water vapor-nanoparticle collisions. It is shown that KTR calculations drastically underpredict the extent of heterogeneous uptake for the examined nanoparticles. PMID:24600691

  1. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake

    NASA Astrophysics Data System (ADS)

    Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H]3- and [M - 5H]5- insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å2 and 808 ± 2 Å2. [M - 4H]4- ions were comprised of more compact (Ω = 676 ± 3 Å2) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å2) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H]4- and [M - 5H]5- ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis.

  2. Separator-Integrated, Reversely Connectable Symmetric Lithium-Ion Battery.

    PubMed

    Wang, Yuhang; Zeng, Jiren; Cui, Xiaoqi; Zhang, Lijuan; Zheng, Gengfeng

    2016-02-24

    A separator-integrated, reversely connectable, symmetric lithium-ion battery is developed based on carbon-coated Li3V2(PO4)3 nanoparticles and polyvinylidene fluoride-treated separators. The Li3V2(PO4)3 nanoparticles are synthesized via a facile solution route followed by calcination in Ar/H2 atmosphere. Sucrose solution is used as the carbon source for uniform carbon coating on the Li3V2(PO4)3 nanoparticles. Both the carbon and the polyvinylidene fluoride treatments substantially improve the cycling life of the symmetric battery by preventing the dissolution and shuttle of the electroactive Li3V2(PO4)3. The obtained symmetric full cell exhibits a reversible capacity of ≈ 87 mA h g(-1), good cycling stability, and capacity retention of ≈ 70% after 70 cycles. In addition, this type of symmetric full cell can be operated in both forward and reverse connection modes, without any influence on the cycling of the battery. Furthermore, a new separator integration approach is demonstrated, which enables the direct deposition of electroactive materials for the battery assembly and does not affect the electrochemical performance. A 10-tandem-cell battery assembled without differentiating the electrode polarity exhibits a low thickness of ≈ 4.8 mm and a high output voltage of 20.8 V.

  3. Bayesian deconvolution of mass and ion mobility spectra: from binary interactions to polydisperse ensembles.

    PubMed

    Marty, Michael T; Baldwin, Andrew J; Marklund, Erik G; Hochberg, Georg K A; Benesch, Justin L P; Robinson, Carol V

    2015-04-21

    Interpretation of mass spectra is challenging because they report a ratio of two physical quantities, mass and charge, which may each have multiple components that overlap in m/z. Previous approaches to disentangling the two have focused on peak assignment or fitting. However, the former struggle with complex spectra, and the latter are generally computationally intensive and may require substantial manual intervention. We propose a new data analysis approach that employs a Bayesian framework to separate the mass and charge dimensions. On the basis of this approach, we developed UniDec (Universal Deconvolution), software that provides a rapid, robust, and flexible deconvolution of mass spectra and ion mobility-mass spectra with minimal user intervention. Incorporation of the charge-state distribution in the Bayesian prior probabilities provides separation of the m/z spectrum into its physical mass and charge components. We have evaluated our approach using systems of increasing complexity, enabling us to deduce lipid binding to membrane proteins, to probe the dynamics of subunit exchange reactions, and to characterize polydispersity in both protein assemblies and lipoprotein Nanodiscs. The general utility of our approach will greatly facilitate analysis of ion mobility and mass spectra.

  4. Using Measurements of Mobility, Diffusion, and Dispersion to Predict Separation Resolution in DNA Electrophoresis

    NASA Astrophysics Data System (ADS)

    Lo, Roger

    2005-03-01

    Electrophoresis of DNA continues to be a key component in a wide variety of genomic analysis assays. In order to customize and optimize these assay systems, much effort has been directed to improve and predict separation resolution using various sieving matrices and experimental platforms. Predicting separation resolution requires a much more detailed understanding of mobility, diffusion, and dispersion phenomena of DNA fragments migrating in the sieving matrix than is currently available in literature. In this study, we address this issue by obtaining a series of systematic measurements of mobility, diffusion, and dispersion using an automated DNA sequencer. Using this data, we are able to isolate key factors governing separation performance, and make comparisons with biased reptation theory to extract information on gel structure and predict achievable resolution under each set of operating conditions. We are also able to predict the separation resolution under specific run conditions, thereby giving researchers and engineers the ability to easily tailor DNA separation systems for required separation performance.

  5. Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

    NASA Astrophysics Data System (ADS)

    Phillips, Nancy J.; John, Constance M.; Jarvis, Gary A.

    2016-07-01

    Lipooligosaccharides (LOS) are major microbial virulence factors displayed on the outer membrane of rough-type Gram-negative bacteria. These amphipathic glycolipids are comprised of two domains, a core oligosaccharide linked to a lipid A moiety. Isolated LOS samples are generally heterogeneous mixtures of glycoforms, with structural variability in both domains. Traditionally, the oligosaccharide and lipid A components of LOS have been analyzed separately following mild acid hydrolysis, although important acid-labile moieties can be cleaved. Recently, an improved method was introduced for analysis of intact LOS by MALDI-TOF MS using a thin layer matrix composed of 2,4,6-trihydroxyacetophenone (THAP) and nitrocellulose. In addition to molecular ions, the spectra show in-source "prompt" fragments arising from regiospecific cleavage between the lipid A and oligosaccharide domains. Here, we demonstrate the use of traveling wave ion mobility spectrometry (TWIMS) for IMS-MS and IMS-MS/MS analyses of intact LOS from Neisseria spp. ionized by MALDI. Using IMS, the singly charged prompt fragments for the oligosaccharide and lipid A domains of LOS were readily separated into resolved ion plumes, permitting the extraction of specific subspectra, which led to increased confidence in assigning compositions and improved detection of less abundant ions. Moreover, IMS separation of precursor ions prior to collision-induced dissociation (CID) generated time-aligned, clean MS/MS spectra devoid of fragments from interfering species. Incorporating IMS into the profiling of intact LOS by MALDI-TOF MS exploits the unique domain structure of the molecule and offers a new means of extracting more detailed information from the analysis.

  6. Large-scale collision cross-section profiling on a travelling wave ion mobility mass spectrometer

    PubMed Central

    Lietz, Christopher B.; Yu, Qing; Li, Lingjun

    2014-01-01

    Ion mobility (IM) is a gas-phase electrophoretic method that separates ions according to charge and ion-neutral collision cross-section (CCS). Herein, we attempt to apply a travelling wave (TW) IM polyalanine calibration method to shotgun proteomics and create a large peptide CCS database. Mass spectrometry methods that utilize IM, such as HDMSE, often use high transmission voltages for sensitive analysis. However, polyalanine calibration has only been demonstrated with low voltage transmission used to prevent gas-phase activation. If polyalanine ions change conformation under higher transmission voltages used for HDMSE, the calibration may no longer be valid. Thus, we aimed to characterize the accuracy of calibration and CCS measurement under high transmission voltages on a TW IM instrument using the polyalanine calibration method and found that the additional error was not significant. We also evaluated the potential error introduced by liquid chromatography (LC)-HDMSE analysis, and found it to be insignificant as well, validating the calibration method. Finally, we demonstrated the utility of building a large-population peptide CCS database by investigating the effects of terminal lysine position, via LysC or LysN digestion, on the formation of two structural sub-families formed by triply charged ions. PMID:24845359

  7. Large-Scale Collision Cross-Section Profiling on a Traveling Wave Ion Mobility Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Lietz, Christopher B.; Yu, Qing; Li, Lingjun

    2014-12-01

    Ion mobility (IM) is a gas-phase electrophoretic method that separates ions according to charge and ion-neutral collision cross-section (CCS). Herein, we attempt to apply a traveling wave (TW) IM polyalanine calibration method to shotgun proteomics and create a large peptide CCS database. Mass spectrometry methods that utilize IM, such as HDMSE, often use high transmission voltages for sensitive analysis. However, polyalanine calibration has only been demonstrated with low voltage transmission used to prevent gas-phase activation. If polyalanine ions change conformation under higher transmission voltages used for HDMSE, the calibration may no longer be valid. Thus, we aimed to characterize the accuracy of calibration and CCS measurement under high transmission voltages on a TW IM instrument using the polyalanine calibration method and found that the additional error was not significant. We also evaluated the potential error introduced by liquid chromatography ( LC)-HDMSE analysis, and found it to be insignificant as well, validating the calibration method. Finally, we demonstrated the utility of building a large-population peptide CCS database by investigating the effects of terminal lysine position, via LysC or LysN digestion, on the formation of two structural sub-families formed by triply charged ions.

  8. Dopant-assisted negative photoionization ion mobility spectrometry for sensitive detection of explosives.

    PubMed

    Cheng, Shasha; Dou, Jian; Wang, Weiguo; Chen, Chuang; Hua, Lei; Zhou, Qinghua; Hou, Keyong; Li, Jinghua; Li, Haiyang

    2013-01-01

    Ion mobility spectrometry (IMS) is a key trace detection technique for explosives and the development of a simple, stable, and efficient nonradioactive ionization source is highly demanded. A dopant-assisted negative photoionization (DANP) source has been developed for IMS, which uses a commercial VUV krypton lamp to ionize acetone as the source of electrons to produce negative reactant ions in air. With 20 ppm of acetone as the dopant, a stable current of reactant ions of 1.35 nA was achieved. The reactant ions were identified to be CO(3)(-)(H(2)O)(n) (K(0) = 2.44 cm(2) V(-1) s(-1)) by atmospheric pressure time-of-flight mass spectrometry, while the reactant ions in (63)Ni source were O(2)(-)(H(2)O)(n) (K(0) = 2.30 cm(2) V(-1) s(-1)). Finally, its capabilities for detection of common explosives including ammonium nitrate fuel oil (ANFO), 2,4,6-trinitrotoluene (TNT), N-nitrobis(2-hydroxyethyl)amine dinitrate (DINA), and pentaerythritol tetranitrate (PETN) were evaluated, and the limits of detection of 10 pg (ANFO), 80 pg (TNT), and 100 pg (DINA) with a linear range of 2 orders of magnitude were achieved. The time-of-flight mass spectra obtained with use of DANP source clearly indicated that PETN and DINA can be directly ionized by the ion-association reaction of CO(3)(-) to form PETN·CO(3)(-) and DINA·CO(3)(-) adduct ions, which result in good sensitivity for the DANP source. The excellent stability, good sensitivity, and especially the better separation between the reactant and product ion peaks make the DANP a potential nonradioactive ionization source for IMS.

  9. Partitioning of mobile ions between ion exchange polymers and aqueous salt solutions: importance of counter-ion condensation.

    PubMed

    Kamcev, Jovan; Galizia, Michele; Benedetti, Francesco M; Jang, Eui-Soung; Paul, Donald R; Freeman, Benny D; Manning, Gerald S

    2016-02-17

    Equilibrium partitioning of ions between a membrane and a contiguous external solution strongly influences transport properties of polymeric membranes used for water purification and energy generation applications. This study presents a theoretical framework to quantitatively predict ion sorption from aqueous electrolytes (e.g., NaCl, MgCl2) into charged (i.e., ion exchange) polymers. The model was compared with experimental NaCl, MgCl2, and CaCl2 sorption data in commercial cation and anion exchange membranes. Ion sorption in charged polymers was modeled using a thermodynamic approach based on Donnan theory coupled with Manning's counter-ion condensation theory to describe non-ideal behavior of ions in the membrane. Ion activity coefficients in solution were calculated using the Pitzer model. The resulting model, with no adjustable parameters, provides remarkably good agreement with experimental values of membrane mobile salt concentration. The generality of the model was further demonstrated using literature data for ion sorption of various electrolytes in charged polymers, including HCl sorption in Nafion. PMID:26840776

  10. The role of ion optics modeling in the design and development of ion mobility spectrometers

    NASA Astrophysics Data System (ADS)

    Griffin, Matthew T.

    2005-05-01

    Detection of trace gases by ion mobility spectroscopy (IMS) has become common in recent years. In fact, IMS devices are the most commonly deployed military devices for the detection of classical chemical warfare agents (CWA). IMS devices are protecting the homeland by aiding first responders in the identification of toxic industrial chemicals (TICs) and providing explosive and narcotic screening systems. Spurred by the asymmetric threat posed by new threat agents and the ever expanding list of toxic chemicals, research in the development, improvement, and optimization of IMS systems has increased. Much of the research is focused on increasing the sensitivity and selectivity of IMS systems. Ion optics is a large area of study in the field of mass spectrometry, but has been mostly overlooked in the design and development of IMS systems. Ion optics provides insight into particle trajectories, duty cycle, and efficiency of these systems. This paper will outline the role that ion optics can have in the development of IMS systems and introduce the trade space for traditional IMS as well as differential mobility spectroscopy.

  11. The Role of Oxygen in the Formation of TNT Product Ions in Ion Mobility Spectrometry

    SciTech Connect

    Daum, Keith Alvin; Atkinson, David Alan; Ewing, Robert Gordon

    2002-03-01

    The atmospheric pressure ionization of 2,4,6-trinitrotoluene (TNT) in air yields the (TNT-H)- product ion. It is generally accepted that this product ion is formed by the direct proton abstraction of neutral TNT by O2- reactant ions. Data presented here demonstrate the reaction involves the formation of an intermediate (TNT·O2)-, from the association of either TNT+O2- or TNT-+O2. This intermediate has two subsequent reaction branches. One of these branches involves simple dissociation of the intermediate to TNT-; the other branch is a terminal reaction that forms the typically observed (TNT-H)- ion via proton abstraction. The dissociation reaction involving electron transfer to TNT- appeared to be kinetically favored and prevailed at low concentrations of oxygen (less than 2%). The presence of significant amounts of oxygen, however, resulted in the predominant formation of the (TNT-H)- ion by the terminal reaction branch. With TNT- in the system, either from direct electron attachment or by simple dissociation of the intermediate, increasing levels of oxygen in the system will continue to reform the intermediate, allowing the cycle to continue until proton abstraction occurs. Key to understanding this complex reaction pathway is that O2- was observed to transfer an electron directly to neutral TNT to form the TNT-. At oxygen levels of less than 2%, the TNT- ion intensity increased with increasing levels of oxygen (and O2-) and was larger than the (TNT-H)- ion intensity. As the oxygen level increased from 2 to 10%, the (TNT-H)- product ion became predominant. The potential reaction mechanisms were investigated with an ion mobility spectrometer, which was configured to independently evaluate the ionization pathways.

  12. Application of Ion Mobility Mass Spectrometry for Detection and Identification of Oxidized Organic Species during SOAS 2013

    NASA Astrophysics Data System (ADS)

    Canagaratna, M. R.; Krechmer, J.; Kimmel, J.; Junninen, H.; Knochenmuss, R.; Cubison, M.; Massoli, P.; Stark, H.; Jayne, J. T.; Jimenez, J. L.; Worsnop, D. R.

    2013-12-01

    We present results obtained with a chemical ionization ion mobility time-of-flight mass spectrometer (CI-IMS-TOF) that was deployed during the Southern Oxidant and Aerosol Study (SOAS) at the Supersite in Centreville, AL. This two dimensional technique, which separates ions on the basis of their interactions with buffer gases before analysis by high-resolution time-of-flight mass spectrometry, allows for detailed separation and identification of isomeric and isobaric species. During SOAS the IMS-TOF was coupled to a chemical ionization source that utilized NO3- as the reagent ion. The NO3- reagent ion clusters with highly oxidized species and allows for a unique means of directly detecting particle phase precursors in the gas phase. Gas phase molecules corresponding to oxidized products of isoprene and terpenes were detected throughout the campaign with a time resolution of 5 minutes. Ion mobility separation and trends observed for several of these key species are discussed. In addition to ambient sampling, the CI-IMS-TOF was also operated behind a potential aerosol mass (PAM) flow reactor which exposed ambient air to high levels of OH radical. Ambient CI-IMS-TOF spectra obtained with and without the flow reactor are presented and compared with laboratory flow reactor spectra generated from isoprene and terpene precursors.

  13. Interrogating viral capsid assembly with ion mobility-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Uetrecht, Charlotte; Barbu, Ioana M.; Shoemaker, Glen K.; van Duijn, Esther; Heck, Albert J. R.

    2011-02-01

    Most proteins fulfil their function as part of large protein complexes. Surprisingly, little is known about the pathways and regulation of protein assembly. Several viral coat proteins can spontaneously assemble into capsids in vitro with morphologies identical to the native virion and thus resemble ideal model systems for studying protein complex formation. Even for these systems, the mechanism for self-assembly is still poorly understood, although it is generally thought that smaller oligomeric structures form key intermediates. This assembly nucleus and larger viral assembly intermediates are typically low abundant and difficult to monitor. Here, we characterised small oligomers of Hepatitis B virus (HBV) and norovirus under equilibrium conditions using native ion mobility mass spectrometry. This data in conjunction with computational modelling enabled us to elucidate structural features of these oligomers. Instead of more globular shapes, the intermediates exhibit sheet-like structures suggesting that they are assembly competent. We propose pathways for the formation of both capsids.

  14. Ion mobility spectrometry for pharmacokinetic studies – exemplary application

    PubMed Central

    Ruzsanyi, V.

    2013-01-01

    Breath analysis is an attractive non-invasive method for diagnosis and therapeutic monitoring. It uses endogenously produced compounds and metabolites of isotopically labelled precursors. In order to make such tests clinically useful, it is important to have relatively small portable instruments detecting volatile compounds within short time. A particularly promising analytical technique is ion mobility spectrometry (IMS) coupled to a multicapillary column (MCC). The present paper focuses on demonstrating the suitability of breath analysis for pharmacokinetic applications using MCC-IMS with respect to practicability and reproducibility testing the model substrate eucalyptol. Validation of the MCC-IMS measurements were performed using proton transfer reaction mass spectrometry (PTR-MS) and resulted in an excellent correspondence of the time-dependent concentrations presented by the two different analytical techniques. Moreover, the good accordance in variance of kinetic parameters with repeated measures, and the determined inter-subject differences indicate the eligibility of the analysis method. PMID:24287589

  15. Development of Ion Mobility Spectrometry for Exobiology Flight Experiments

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Carle, Glenn C.; Humphry, Donald E.; Shao, Maxine; Takeuchi, Nori; Chang, Sherwood (Technical Monitor)

    1996-01-01

    Ion Mobility Spectrometry (IMS) can provide gas chromatography with sample identification independent of sample retention time, with minimal interface. Initial commercial methods of IMS however, did not possess sufficient analytical capabilities and presented operational parameters which were unsuitable for exobiology missions. Subsequent development of IMS technology, with the focus on exobiology analytical requirements and mission imposed operational limitations, has produced an IMS interfaced with a GC capable of fulfilling the analytical requirements of several exobiology missions. Future exobiology missions will require further development of the IMS, particularly in the areas of overall instrument miniaturization and complex sample identification. The evolution of the exobiology focused IMS will be presented up to the current prototype design, which is a component of several proposed exobiology instruments. Areas of future development will also be discussed.

  16. Precise determination of nonlinear function of ion mobility for explosives and drugs at high electric fields for microchip FAIMS.

    PubMed

    Guo, Dapeng; Wang, Yonghuan; Li, Lingfeng; Wang, Xiaozhi; Luo, Jikui

    2015-01-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) separates ions by utilizing the characteristics of nonlinear ion mobility at high and low electric fields. Accurate ion discrimination depends on the precise solution of nonlinear relationships and is essential for accurate identification of ion species for applications. So far, all the nonlinear relationships of ion mobility obtained are based at low electric fields (E/N <65 Td). Microchip FAIMS (μ-FAIMS) with small dimensions has high electric field up to E/N = 250 Td, making the approximation methods and conclusions for nonlinear relationships inappropriate for these systems. In this paper, we deduced nonlinear functions based on the first principle and a general model. Furthermore we considered the hydrodynamics of gas flow through microchannels. We then calculated the specific alpha coefficients for cocaine, morphine, HMX, TNT and RDX, respectively, based on their FAIMS spectra measured by μ-FAIMS system at ultra-high fields up to 250 Td. The results show that there is no difference in nonlinear alpha functions obtained by the approximation and new method at low field (<120 Td), but the error induced by using approximation method increases monotonically with the increase in field, and could be as much as 30% at a field of 250 Td.

  17. Materials for Electroactive Ion-Exchange (EaIX) Separations of Pertechnetate Ion

    SciTech Connect

    Stender, Matthias; Hubler, Timothy L.; Alhoshan, Mansour; Smyrl, William H.

    2004-03-29

    Many contaminants of interest to the U.S. Department of Energy (DOE) exist as anions (e.g. chromate, pertechnetate and nitrate). The objective of this study is to develop Electroactive Ion-Exchange (EaIX) materials. Such materials can be used to separate pertechnetate ion from radioactive wastes located at DOE sites while limiting the amount of secondary wastes generated. We have developed a synthetic strategy to prepare vinyl-bipyridyl and -terpyridyl ligands which allow incorporation of ion-selective architectures with a polymerizable handle. Fe complexes formed with these ligands provide the working core of the electroactive polymers. The polymers can be directly used as materials for EaIX or they can be incorporated into porous composite materials that are then used for EaIX.

  18. Quality issues in the use of ion mobility spectrometry

    NASA Astrophysics Data System (ADS)

    Poziomek, Edward J.; Homstead, Juliana; Almeer, Saeed H.

    1998-12-01

    Ion mobility spectrometry (IMS) is often used in the detection of explosives and drugs in the laboratory and field scenarios. It is gaining popularity in the semiquantitative analysis of these and related compounds. We have successfully used IMS in studies with cocaine, 2,4,6 trinitrotoluene (TNT) and similar chemicals, and have developed a protocol to access and ensure the quality of our data. This protocol employs TNT as the reference standard in the IMS negative mode and cocaine hydrochloride as the reference standard in the IMS positive mode. A five-point calibration curve is normally generated for each reference compound in order to determine a concentration level suitable for quality control (QC) check solutions. We have established peak amplitudes and reduced mobility constants for the QC solutions that must be met each day before proceeding with analyses. Any deviation from these criteria requires assessment of the problem and appropriate corrective action. We have found this procedure helpful in maintaining data quality, and in providing an early indication of potential problems. The present paper focuses on the use of IMS with explosives though several examples are given with cocaine hydrochloride.

  19. Analysis of a series of chlorogenic acid isomers using differential ion mobility and tandem mass spectrometry.

    PubMed

    Willems, Jamie L; Khamis, Mona M; Mohammed Saeid, Waleed; Purves, Randy W; Katselis, George; Low, Nicholas H; El-Aneed, Anas

    2016-08-24

    Chlorogenic acids are among the most abundant phenolics found in the human diet. Of these, the mono-caffeoylquinic acids are the predominant phenolics found in fruits, such as apples and pears, and products derived from them. In this research, a comprehensive study of the electrospray ionization (ESI) tandem mass spectrometric (MS/MS) dissociation behavior of the three most common mono-caffeoylquinic acids, namely 5-O-caffeoylquinic acid (5-CQA), 3-O-caffeoylquinic acid (3-CQA) and 4-O-caffeoylquinic acid (4-CQA), were determined using both positive and negative ionization. All proposed structures of the observed product ions were confirmed with second-generation MS(3) experiments. Similarities and differences between the dissociation pathways in the positive and negative ion modes are discussed, confirming the proposed structures and the established MS/MS fingerprints. MS/MS dissociation was primarily driven via the cleavage of the ester bond linking the quinic acid moiety to the caffeic acid moiety within tested molecules. Despite being structural isomers with the same m/z values and dissociation behaviors, the MS/MS data in the negative ion mode was able to differentiate the three isomers based on ion intensity for the major product ions, observed at m/z 191, 179 and 173. This differentiation was consistent among various MS instruments. In addition, ESI coupled with high-field asymmetric waveform ion mobility spectrometry-mass spectrometry (ESI-FAIMS-MS) was employed for the separation of these compounds for the first time. By combining MS/MS data and differential ion mobility, a method for the separation and identification of mono-caffeoylquinic in apple/pear juice samples was developed with a run time of less than 1 min. It is envisaged that this methodology could be used to identify pure juices based on their chlorogenic acid profile (i.e., metabolomics), and could also be used to detect juice-to-juice adulteration (e.g., apple juice addition to pear juice).

  20. Analysis of a series of chlorogenic acid isomers using differential ion mobility and tandem mass spectrometry.

    PubMed

    Willems, Jamie L; Khamis, Mona M; Mohammed Saeid, Waleed; Purves, Randy W; Katselis, George; Low, Nicholas H; El-Aneed, Anas

    2016-08-24

    Chlorogenic acids are among the most abundant phenolics found in the human diet. Of these, the mono-caffeoylquinic acids are the predominant phenolics found in fruits, such as apples and pears, and products derived from them. In this research, a comprehensive study of the electrospray ionization (ESI) tandem mass spectrometric (MS/MS) dissociation behavior of the three most common mono-caffeoylquinic acids, namely 5-O-caffeoylquinic acid (5-CQA), 3-O-caffeoylquinic acid (3-CQA) and 4-O-caffeoylquinic acid (4-CQA), were determined using both positive and negative ionization. All proposed structures of the observed product ions were confirmed with second-generation MS(3) experiments. Similarities and differences between the dissociation pathways in the positive and negative ion modes are discussed, confirming the proposed structures and the established MS/MS fingerprints. MS/MS dissociation was primarily driven via the cleavage of the ester bond linking the quinic acid moiety to the caffeic acid moiety within tested molecules. Despite being structural isomers with the same m/z values and dissociation behaviors, the MS/MS data in the negative ion mode was able to differentiate the three isomers based on ion intensity for the major product ions, observed at m/z 191, 179 and 173. This differentiation was consistent among various MS instruments. In addition, ESI coupled with high-field asymmetric waveform ion mobility spectrometry-mass spectrometry (ESI-FAIMS-MS) was employed for the separation of these compounds for the first time. By combining MS/MS data and differential ion mobility, a method for the separation and identification of mono-caffeoylquinic in apple/pear juice samples was developed with a run time of less than 1 min. It is envisaged that this methodology could be used to identify pure juices based on their chlorogenic acid profile (i.e., metabolomics), and could also be used to detect juice-to-juice adulteration (e.g., apple juice addition to pear juice

  1. Improved Isobaric Tandem Mass Tag Quantification by Ion Mobility-Mass Spectrometry

    PubMed Central

    Li, Lingjun

    2014-01-01

    Isobaric tandem mass tags are an attractive alternative to mass difference tags and label free approaches for quantitative proteomics due to the high degree of multiplexing that can be performed with their implementation. A drawback of tandem mass tags are that the co-isolation and co-fragmentation of labeled peptide precursors can result in chimeric MS/MS spectra that can underestimate the fold-change expression of each peptide. Two methods (QuantMode and MS3) have addressed this concern for ion trap and orbitrap instruments, but there is still a need to solve this problem for quadrupole time-of-flight (Q-TOF) instruments. Ion mobility (IM) separations coupled to Q-TOF instruments have the potential to mitigate MS/MS spectra chimeracy since IM-MS has the ability to separate ions based on charge, m/z, and collision cross section (CCS). This work presents results that showcase the power of IM-MS to improve tandem mass tag peptide quantitation accuracy by resolving co-isolated differently charged and same charged peptides prior to MS/MS fragmentation. PMID:24677527

  2. Ambient temperature nanoelectrospray ion mobility detector for high performance liquid chromatography in determining amines.

    PubMed

    Chen, Chuang; Hou, Keyong; Wang, Weiguo; Li, Jinghua; Li, Haiyang

    2014-09-01

    A nanoelectrospray ionization ion mobility spectrometer (nanoESI-IMS) working at ambient pressure and ambient temperature was developed as a detector of high performance liquid chromatography (HPLC) to achieve sensitive detection of amines with no derivatization and meanwhile provide another dimension of separation. The easier desolvation property of the charged droplets formed in nanoESI source enabled complete desolvation of the product ions of sixteen amines and drugs using the nanoESI-IMS at ambient temperature. Working at ambient temperature was good for suppressing the dissociation of thermal volatile ions, such as only the proton adducted molecular ions were observed for morphine in the nanoESI-IMS. Besides, the resolving power of the nanoESI-IMS also showed an increasing tendency as lowering the working temperature, an increment of 19 percent and 10 percent was observed for diethylamine and triethylamine as the temperature dropped from 92°C to 32°C. The resolving power of the nanoESI-IMS at 32°C for the 16 tested compounds was amid 33-44. With the nanoESI-IMS coupled to HPLC, a six-compound mixture including isomers was successfully separated and detected without any derivatization. And linear response ranges of 1 to 20, 0.5 to 20, and 0.8 to 20μgml(-1) and limits of detection of 0.25, 0.15, and 0.17μgml(-1) for triethylamine, diethylamine, and butylamine, respectively, were obtained with the hyphenated system. These results showed the excellent performance of the two-dimensional separation and detection method in direct qualitative and quantitative analyses of amines.

  3. Dynamical Structures in Phase-Separated Films Deposited under Ion Bombardment

    SciTech Connect

    He, J. H.; Carosella, C. A.; Hubler, G. K.; Knies, D. L.; Qadri, S. B.; Grabowski, K. S.

    2009-03-10

    We report our experimental observation of ion bombardment effect on the film structures generated by co-evaporation of Au and silica. Three states are identified depending on the incident ion energy and beam current. Moderate ion bombardment creates nanoscale compositional modulations along the film growth direction. Strong ion bombardment induces disappearance of the compositional modulations. At still higher energy and flux, energetic ions sputter away all deposited atoms. The observed phenomena reflect synergistic effects of ion bombardment on the film growth in phase separated systems. Our observations suggest that ion beams can be employed to control the film structures in the deposition of phase-separated films.

  4. Ion mobility spectrometry for the rapid analysis of over-the-counter drugs and beverages

    PubMed Central

    Fernández-Maestre, Roberto

    2009-01-01

    In the pharmaceutical industry, there are increasing requirements for analytical methods in quality assessment for the production of drugs. In this investigation, ion mobility spectrometry (IMS) was used for the rapid qualitative separation and identification of active ingredients in generic over-the-counter drugs and food additives in beverages. The active ingredients determined in drugs were acetaminophen, aspartame, bisacodyl, caffeine, dextromethorphan, diphenhydramine, famotidine, glucosamine, guaifenesin, loratadine, niacin, phenylephrine, pyridoxine, thiamin, and tetrahydrozoline. Aspartame and caffeine were determined in beverages. Fourteen over-the-counter drugs and beverages were analyzed. Analysis times below 10 s were obtained for IMS, and reduced mobilities were reported for the first time for 12 compounds. A quadrupole mass spectrometer coupled to a mobility spectrometer was used to assure a correct peak assignation. The combination of fast analysis, low cost, and inexpensive maintenance of IMS instruments makes IMS an attractive technique for the qualitative determination of the active ingredients in over-the-counter drugs and food additives in manufacture quality control and cleaning verification for the drug and food industries. PMID:20835390

  5. Ion mobility spectrometry for the rapid analysis of over-the-counter drugs and beverages.

    PubMed

    Fernández-Maestre, Roberto; Hill, Herbert H

    2009-08-01

    In the pharmaceutical industry, there are increasing requirements for analytical methods in quality assessment for the production of drugs. In this investigation, ion mobility spectrometry (IMS) was used for the rapid qualitative separation and identification of active ingredients in generic over-the-counter drugs and food additives in beverages. The active ingredients determined in drugs were acetaminophen, aspartame, bisacodyl, caffeine, dextromethorphan, diphenhydramine, famotidine, glucosamine, guaifenesin, loratadine, niacin, phenylephrine, pyridoxine, thiamin, and tetrahydrozoline. Aspartame and caffeine were determined in beverages. Fourteen over-the-counter drugs and beverages were analyzed. Analysis times below 10 s were obtained for IMS, and reduced mobilities were reported for the first time for 12 compounds. A quadrupole mass spectrometer coupled to a mobility spectrometer was used to assure a correct peak assignation. The combination of fast analysis, low cost, and inexpensive maintenance of IMS instruments makes IMS an attractive technique for the qualitative determination of the active ingredients in over-the-counter drugs and food additives in manufacture quality control and cleaning verification for the drug and food industries.

  6. Ion mobility spectrometry-mass spectrometry (IMS-MS) for on- and offline analysis of atmospheric gas and aerosol species

    NASA Astrophysics Data System (ADS)

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; Budisulistiorini, Sri H.; Zhang, Haofei; Surratt, Jason D.; Knochenmuss, Richard; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose-Luis; Canagaratna, Manjula R.

    2016-07-01

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS-MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS-MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI-IMS-MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambient field campaign in the forested SE US. The ambient IMS-MS signals are consistent with laboratory IMS-MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS-MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS-MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of oligomers, and confirm the

  7. Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species

    DOE PAGESBeta

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; et al

    2016-07-25

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS–MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS–MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI–IMS–MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambientmore » field campaign in the forested SE US. The ambient IMS–MS signals are consistent with laboratory IMS–MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS–MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS–MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of

  8. Separation of traces of metal ions from sodium matrices

    NASA Technical Reports Server (NTRS)

    Korkisch, J.; Orlandini, K. A.

    1969-01-01

    Method for isolating metal ion traces from sodium matrices consists of two extractions and an ion exchange step. Extraction is accomplished by using 2-thenoyltrifluoracetone and dithizone followed by cation exchange.

  9. Determination of N-linked glycosylation in viral glycoproteins by negative ion mass spectrometry and ion mobility

    PubMed Central

    Bitto, David; Harvey, David J.; Halldorsson, Steinar; Doores, Katie J.; Pritchard, Laura K.; Huiskonen, Juha T.; Bowden, Thomas A.; Crispin, Max

    2016-01-01

    Summary Glycan analysis of virion-derived glycoproteins is challenging due to the difficulties in glycoprotein isolation and low sample abundance. Here, we describe how ion mobility mass spectrometry can be used to obtain spectra from virion samples. We also describe how negative ion fragmentation of glycans can be used to probe structural features of virion glycans. PMID:26169737

  10. An online peak extraction algorithm for ion mobility spectrometry data.

    PubMed

    Kopczynski, Dominik; Rahmann, Sven

    2015-01-01

    Ion mobility (IM) spectrometry (IMS), coupled with multi-capillary columns (MCCs), has been gaining importance for biotechnological and medical applications because of its ability to detect and quantify volatile organic compounds (VOC) at low concentrations in the air or in exhaled breath at ambient pressure and temperature. Ongoing miniaturization of spectrometers creates the need for reliable data analysis on-the-fly in small embedded low-power devices. We present the first fully automated online peak extraction method for MCC/IMS measurements consisting of several thousand individual spectra. Each individual spectrum is processed as it arrives, removing the need to store the measurement before starting the analysis, as is currently the state of the art. Thus the analysis device can be an inexpensive low-power system such as the Raspberry Pi. The key idea is to extract one-dimensional peak models (with four parameters) from each spectrum and then merge these into peak chains and finally two-dimensional peak models. We describe the different algorithmic steps in detail and evaluate the online method against state-of-the-art peak extraction methods.

  11. Towards metals analysis using corona discharge ionization ion mobility spectrometry.

    PubMed

    Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

    2016-02-25

    For the first time, the capability of corona discharge ionization ion mobility spectrometry (CD-IMS) in the determination of metal complex was evaluated. The extreme simplicity of dispersive liquid-liquid microextraction (DLLME) coupled to the high sensitivity of CD-IMS measurement could make this combination really useful for simple, rapid, and sensitive determination of metals in different samples. In this regard, mercury, as a model metal, was complexed with diethyldithiocarbamate (DEDTC), and then extracted into the carbon tetrachloride using DLLME. Some parameters affecting the extraction efficiency, including the type and volume of the extraction solvent, the type and volume of the disperser solvent, the concentration of the chelating agent, salt addition and, pH were exhaustively investigated. Under the optimized condition, the enrichment factor was obtained to be 142. The linear range of 0.035-10.0 μg mL(-1) with r(2) = 0.997 and the detection limit of 0.010 μg mL(-1) were obtained. The relative standard deviation values were calculated to be lower than 4% and 8% for intra-day and inter-day, respectively. Finally, the developed method was successfully applied for the extraction and determination of mercury in various real samples. The satisfactory results revealed the capability of the proposed method in trace analysis without tedious derivatization or hydride generation.

  12. An online peak extraction algorithm for ion mobility spectrometry data.

    PubMed

    Kopczynski, Dominik; Rahmann, Sven

    2015-01-01

    Ion mobility (IM) spectrometry (IMS), coupled with multi-capillary columns (MCCs), has been gaining importance for biotechnological and medical applications because of its ability to detect and quantify volatile organic compounds (VOC) at low concentrations in the air or in exhaled breath at ambient pressure and temperature. Ongoing miniaturization of spectrometers creates the need for reliable data analysis on-the-fly in small embedded low-power devices. We present the first fully automated online peak extraction method for MCC/IMS measurements consisting of several thousand individual spectra. Each individual spectrum is processed as it arrives, removing the need to store the measurement before starting the analysis, as is currently the state of the art. Thus the analysis device can be an inexpensive low-power system such as the Raspberry Pi. The key idea is to extract one-dimensional peak models (with four parameters) from each spectrum and then merge these into peak chains and finally two-dimensional peak models. We describe the different algorithmic steps in detail and evaluate the online method against state-of-the-art peak extraction methods. PMID:26157473

  13. Advancing the High Throughput Identification of Liver Fibrosis Protein Signatures Using Multiplexed Ion Mobility Spectrometry

    SciTech Connect

    Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Jacobs, Jon M.; Diamond, Deborah L.; Brown, Roslyn N.; Ibrahim, Yehia M.; Orton, Daniel J.; Piehowski, Paul D.; Purdy, David E.; Moore, Ronald J.; Danielson, William F.; Monroe, Matthew E.; Crowell, Kevin L.; Slysz, Gordon W.; Gritsenko, Marina A.; Sandoval, John D.; Lamarche, Brian L.; Matzke, Melissa M.; Webb-Robertson, Bobbie-Jo M.; Simons, Brenna C.; McMahon, Brian J.; Bhattacharya, Renuka; Perkins, James D.; Carithers, Robert L.; Strom, Susan; Self, Steven; Katze, Michael G.; Anderson, Gordon A.; Smith, Richard D.

    2014-04-01

    Rapid diagnosis of disease states using less invasive, safer, and more clinically acceptable approaches than presently employed is an imperative goal for the field of medicine. While mass spectrometry (MS)-based proteomics approaches have attempted to meet these objectives, challenges such as the enormous dynamic range of protein concentrations in clinically relevant biofluid samples coupled with the need to address human biodiversity have slowed their employment. Herein, we report on the use of a new platform that addresses these challenges by coupling technical advances in rapid gas phase multiplexed ion mobility spectrometry (IMS) separations [1, 2] with liquid chromatography (LC) and MS to dramatically increase measurement sensitivity and throughput, further enabling future MS-based clinical applications. An initial application of the LC-IMS-MS platform for the analysis of blood serum samples from stratified post-liver transplant patients with recurrent fibrosis progression illustrates its potential utility for disease characterization and use in personalized medicine [3, 4].

  14. Advances in ion mobility spectrometry–mass spectrometry reveal key insights into amyloid assembly☆

    PubMed Central

    Woods, L.A.; Radford, S.E.; Ashcroft, A.E.

    2013-01-01

    Interfacing ion mobility spectrometry to mass spectrometry (IMS–MS) has enabled mass spectrometric analyses to extend into an extra dimension, providing unrivalled separation and structural characterization of lowly populated species in heterogeneous mixtures. One biological system that has benefitted significantly from such advances is that of amyloid formation. Using IMS–MS, progress has been made into identifying transiently populated monomeric and oligomeric species for a number of different amyloid systems and has led to an enhanced understanding of the mechanism by which small molecules modulate amyloid formation. This review highlights recent advances in this field, which have been accelerated by the commercial availability of IMS–MS instruments. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. PMID:23063533

  15. Mass Spectrometric Collisional Activation and Product Ion Mobility of Human Serum Neutral Lipid Extracts

    PubMed Central

    Hankin, Joseph A.; Barkley, Robert M.; Zemski-Berry, Karin; Deng, Yiming; Murphy, Robert C.

    2016-01-01

    A novel method for lipid analysis called CTS (collisional activation and traveling wave mass spectrometry) involving tandem mass spectrometry of all precursor ions with ion mobility determinations of all product ions was applied to a sample of human serum. The resulting four dimensional data set (precursor ion, product ion, ion mobility values, and intensity) was found to be useful for characterization of lipids as classes as well as identification of specific species. Utilization of ion mobility measurements of the product ions is a novel approach for lipid analysis. The trends and patterns of product mobility values when visually displayed yield information on lipid classes and specific species independent of mass determination. The collection of a comprehensive set of data that incorporates all precursor-product relationships combined with ion mobility measurements of all products enables data analysis where different molecular properties can be juxtaposed and analyzed to assist with class and species identification. Overall, CTS is powerful, specific, and comprehensive method for lipid analysis. PMID:27213895

  16. Characterization of TATP gas phase product ion chemistry via isotope labeling experiments using ion mobility spectrometry interfaced with a triple quadrupole mass spectrometer.

    PubMed

    Tomlinson-Phillips, Jill; Wooten, Alfred; Kozole, Joseph; Deline, James; Beresford, Pamela; Stairs, Jason

    2014-09-01

    Identification of the fragment ion species associated with the ion reaction mechanism of triacetone triperoxide (TATP), a homemade peroxide-based explosive, is presented. Ion mobility spectrometry (IMS) has proven to be a key analytical technique in the detection of trace explosive material. Unfortunately, IMS alone does not provide chemical identification of the ions detected; therefore, it is unknown what ion species are actually formed and separated by the IMS. In IMS, ions are primarily characterized by their drift time, which is dependent on the ion׳s mass and molecular cross-section; thus, IMS as a standalone technique does not provide structural signatures, which is in sharp contrast to the chemical and molecular information that is generally obtained from other customary analytical techniques, such as NMR, Raman and IR spectroscopy and mass spectrometry. To help study the ion chemistry that gives rise to the peaks observed in IMS, the hardware of two different commercial IMS instruments has been directly coupled to triple quadrupole (QQQ) mass spectrometers, in order to ascertain each ion׳s corresponding mass/charge (m/z) ratios with different dopants at two temperatures. Isotope labeling was then used to help identify and confirm the molecular identity of the explosive fragment and adduct ions of TATP. The m/z values and isotope labeling experiments were used to help propose probable molecular formulas for the ion fragments. In this report, the fragment and adduct ions m/z 58 and 240 of TATP have been confirmed to be [C3H6NH·H](+) and [TATP·NH4](+), respectively; while the fragment ions m/z 73 and 89 of TATP are identified as having the molecular formulas [C4H9NH2](+) and [C4H9O2](+), respectively. It is anticipated that the work in this area will not only help to facilitate improvements in mobility-based detection (IMS and MS), but also aid in the development and optimization of MS-based detection algorithms for TATP.

  17. Characterization of TATP gas phase product ion chemistry via isotope labeling experiments using ion mobility spectrometry interfaced with a triple quadrupole mass spectrometer.

    PubMed

    Tomlinson-Phillips, Jill; Wooten, Alfred; Kozole, Joseph; Deline, James; Beresford, Pamela; Stairs, Jason

    2014-09-01

    Identification of the fragment ion species associated with the ion reaction mechanism of triacetone triperoxide (TATP), a homemade peroxide-based explosive, is presented. Ion mobility spectrometry (IMS) has proven to be a key analytical technique in the detection of trace explosive material. Unfortunately, IMS alone does not provide chemical identification of the ions detected; therefore, it is unknown what ion species are actually formed and separated by the IMS. In IMS, ions are primarily characterized by their drift time, which is dependent on the ion׳s mass and molecular cross-section; thus, IMS as a standalone technique does not provide structural signatures, which is in sharp contrast to the chemical and molecular information that is generally obtained from other customary analytical techniques, such as NMR, Raman and IR spectroscopy and mass spectrometry. To help study the ion chemistry that gives rise to the peaks observed in IMS, the hardware of two different commercial IMS instruments has been directly coupled to triple quadrupole (QQQ) mass spectrometers, in order to ascertain each ion׳s corresponding mass/charge (m/z) ratios with different dopants at two temperatures. Isotope labeling was then used to help identify and confirm the molecular identity of the explosive fragment and adduct ions of TATP. The m/z values and isotope labeling experiments were used to help propose probable molecular formulas for the ion fragments. In this report, the fragment and adduct ions m/z 58 and 240 of TATP have been confirmed to be [C3H6NH·H](+) and [TATP·NH4](+), respectively; while the fragment ions m/z 73 and 89 of TATP are identified as having the molecular formulas [C4H9NH2](+) and [C4H9O2](+), respectively. It is anticipated that the work in this area will not only help to facilitate improvements in mobility-based detection (IMS and MS), but also aid in the development and optimization of MS-based detection algorithms for TATP. PMID:24913870

  18. Decreased Gap Width in a Cylindrical High-Field Asymmetric Waveform Ion Mobility Spectrometry Device Improves Protein Discovery.

    PubMed

    Swearingen, Kristian E; Winget, Jason M; Hoopmann, Michael R; Kusebauch, Ulrike; Moritz, Robert L

    2015-12-15

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an atmospheric pressure ion mobility technique that separates gas phase ions according to their characteristic dependence of ion mobility on electric field strength. FAIMS can be implemented as a means of automated gas-phase fractionation in liquid chromatography-tandem mass spectrometry (LC-MS/MS) experiments. We modified a commercially available cylindrical FAIMS device by enlarging the inner electrode, thereby narrowing the gap and increasing the effective field strength. This modification provided a nearly 4-fold increase in FAIMS peak capacity over the optimally configured unmodified device. We employed the modified FAIMS device for on-line fractionation in a proteomic analysis of a complex sample and observed major increases in protein discovery. NanoLC-FAIMS-MS/MS of an unfractionated yeast tryptic digest using the modified FAIMS device identified 53% more proteins than were identified using an unmodified FAIMS device and 98% more proteins than were identified with unaided nanoLC-MS/MS. We describe here the development of a nanoLC-FAIMS-MS/MS protocol that provides automated gas-phase fractionation for proteomic analysis of complex protein digests. We compare this protocol against prefractionation of peptides with isoelectric focusing and demonstrate that FAIMS fractionation yields comparable protein recovery while significantly reducing the amount of sample required and eliminating the need for additional sample handling. PMID:26560994

  19. Third-order transport properties of ion-swarms from mobility and diffusion coefficients

    NASA Astrophysics Data System (ADS)

    Koutselos, Andreas D.

    2005-08-01

    A method is presented for the calculation of third order transport properties of ions drifting in gases under the action of an electrostatic field with the use of mobility and ion-diffusion coefficients. The approach is based on a three-temperature treatment of the Boltzmann equation for the ion transport and follows the development of generalized Einstein relations (GER), between diffusion coefficients and mobility. The whole procedure is tested by comparison with numerical and molecular dynamics simulation results for three available alkali ion-noble gas systems. Extension to systems involving internal degrees of freedom and inelastic collisions is shown to follow the development of molecular GER.

  20. Ancient Pb and Ti mobilization revealed by Scanning Ion Imaging

    NASA Astrophysics Data System (ADS)

    Kusiak, Monika A.; Whitehouse, Martin J.; Wilde, Simon A.

    2014-05-01

    Zircons from strongly layered early Archean ortho- and paragneisses in ultra-high temperature (UHT) metamorphic rocks of the Napier Complex, Enderby Land, East Antarctica are characterized by complex U-Th-Pb systematics [1,2,3]. A large number of zircons from three samples, Gage Ridge, Mount Sones and Dallwitz Nunatak, are reversely discordant (U/Pb ages older than 207Pb/206Pb ages) with the oldest date of 3.9 Ga [4] (for the grain from Gage Ridge orthogneiss). To further investigate this process, we utilized a novel high spatial resolution Scanning Ion Imaging technique on the CAMECA IMS 1280 at the Natural History Museum in Stockholm. Areas of 70 μm x 70 μm were selected for imaging in mono- and multicollection modes using a ~2 μm rastered primary beam to map out the distribution of 48Ti, 89Y, 180Hf, 232Th, 238U, 204Pb, 206Pb and 207Pb. The ion maps reveal variable distribution of certain elements within analysed grains that can be compared to their CL response. Yttrium, together with U and Th, exhibits zonation visible on the CL images, Hf shows expected minimal variation. Unusual patchiness is visible in the map for Ti and Pb distribution. The bright patches with enhanced signal do not correspond to any zones or to crystal imperfections (e.g. cracks). The presence of patchy titanium is likely to affect Ti-in-zircon thermometry, and patchy Pb affecting 207Pb/206Pb ages, usually considered as more robust for Archean zircons. Using the WinImage program, we produced 207Pb/206Pb ratio maps that allow calculation of 207Pb/206Pb ages for spots of any size within the frame of the picture and at any time after data collection. This provides a new and unique method for obtaining age information from zircon. These maps show areas of enhanced brightness where the 207Pb/206Pb ratio is higher and demonstrate that within these small areas (μm scale) the apparent 207Pb/206Pb age is older, in some of these patches even > 4 Ga. These data are a result of ancient Pb

  1. Ion mobility-mass spectrometry of phosphorylase B ions generated with supercharging reagents but in charge-reducing buffer.

    PubMed

    Hogan, Christopher J; Ogorzalek Loo, Rachel R; Loo, Joseph A; de la Mora, Juan Fernandez

    2010-11-01

    We investigate whether "supercharging" reagents able to shift the charge state distributions (CSDs) of electrosprayed protein ions upward also influence gas-phase protein structure. A differential mobility analyzer and a mass spectrometer are combined in series (DMA-MS) to measure the mass and mobility of monomer and multimeric phosphorylase B ions (monomer molecular weight ∼97 kDa) in atmospheric pressure air. Proteins are electrosprayed from charge-reducing triethylammonium formate in water (pH = 6.8) with and without the addition of the supercharging reagent tetramethylene sulfone (sulfolane). Because the DMA measures ion mobility prior to collisional heating or declustering, it probes the structure of supercharged protein ions immediately following solvent (water) evaporation. As in prior studies, the addition of sulfolane is found to drastically increase both the mean and maximum charge state of phosphorylase B ions. Ions from all protein n-mers were found to yield mobilities that, for a given charge state, were ∼6-10% higher in the absence of sulfolane. We find that the mobility decrease which arises with sulfolane is substantially smaller than that typically observed for folded-to-unfolded transitions in protein ions (where a ∼60% decrease in mobility is typical), suggesting that supercharging reagents do not cause structural protein modifications in solution as large as noted recently by Williams and colleagues [E. R. Williams et al., J. Am. Soc. Mass Spectrom., 2010, 21, 1762-1774]. In fact, the measurements described here indicate that the modest mobility decrease observed can be partly attributed to sulfolane trapping within the protein ions during DMA measurements, and probably also in solution. As the most abundant peaks in measured mass-mobility spectra for ions produced with and without sulfolane correspond to non-covalently bound phosphorylase B dimers, we find that in spite of a change in mobility/cross section, sulfolane addition does not

  2. Determination of metal ions by high-performance liquid chromatographic separation of their hydroxamic acid chelates

    SciTech Connect

    Palmieri, M.D.; Fritz, J.S.

    1987-09-15

    Metal ions are determined by adding N-methylfurohydroxamic acid to an aqueous sample and then separating the metal chelates by direct injection onto a liquid chromatographic column. Separations on a C/sub 8/ silica column and a polystyrene-divinylbenzene column are compared, with better separations seen on the polymeric column. The complexes formed at low pH values are cationic and are separated by an ion pairing mechanism. Retention times and selectivity of the metal complexes can be varied by changing the pH. Several metal ions can be separated and quantified; separation conditions, linear calibration curve ranges, and detection limits are presented for Zr(IV), Hf(IV), Fe(III), Nb(V), Al(III), and Sb(III). Interferences due to the presence of other ions in solution are investigated. Finally, an antiperspirant sample is analyzed for zirconium by high-performance liquid chromatography.

  3. Experimental Evaluation and Optimization of Structures for Lossless Ion Manipulations for Ion Mobility Spectrometry with Time-of-Flight Mass Spectrometry

    SciTech Connect

    Webb, Ian K.; Garimella, Venkata BS; Tolmachev, Aleksey V.; Chen, Tsung-Chi; Zhang, Xinyu; Norheim, Randolph V.; Prost, Spencer A.; Lamarche, Brian L.; Anderson, Gordon A.; Ibrahim, Yehia M.; Smith, Richard D.

    2014-09-05

    We report on the performance of Structures for Lossless Ion Manipulation (SLIM) devices as a means for transmitting ions and performing ion mobility separations (IMS). Ions were successfully transferred from an electrospray ionization (ESI) source to the TOF MS analyzer by means of a linear SLIM device and an alternative arrangement including a 90° turn. First, the linear geometry was optimized for radial confinement by tuning RF on the central ‘rung’ electrodes and potentials on the DC-only guard electrodes. Selecting an appropriate DC guard bias (2-6 V) and RF amplitude (≥160 Vp-p at 750 kHz) resulted in the greatest ion intensities. Close to ideal IMS resolving power was maintained over a range of applied voltages. Second, the 90° turn was optimized for radial confinement by tuning the RF on the rung electrodes and DC on the guard electrodes; however, both resolving power and ion transmission showed a dependence on these voltages and the best conditions for both were > 300 Vp-p RF (685 kHz) and 7-11 V guard DC bias. Both geometries provide IMS resolving powers at the theoretical limit (R~58), showing that the negative “racetrack” effect from turning around a corner can be successfully avoided, as well as the capability for essentially lossless ion transmission.

  4. Analysis of paralytic shellfish toxins using high-field asymmetric waveform ion mobility spectrometry with liquid chromatography-mass spectrometry.

    PubMed

    Beach, Daniel G; Melanson, Jeremy E; Purves, Randy W

    2015-03-01

    The analysis of paralytic shellfish toxins (PSTs) by liquid chromatography-mass spectrometry remains a challenge because of their high polarity, large number of analogues and the complex matrix in which they occur. Here we investigate the potential utility of high-field asymmetric waveform ion mobility spectrometry (FAIMS) as a gas-phase ion separation tool for analysis of PSTs by mass spectrometry. We investigate the separation of PSTs using FAIMS with two divergent goals: using FAIMS as a primary separation tool for rapid screening by electrospray ionization (ESI)-FAIMS-MS or combined with LC in a multidimensional LC-ESI-FAIMS-MS separation. First, a survey of the parameters that affect the sensitivity and selectivity of PST analysis by FAIMS was carried out using ESI-FAIMS-MS. In particular, the use of acetonitrile as a gas additive in the carrier gas flow offered good separation of all PST epimeric pairs. A second set of FAIMS conditions was also identified, which focussed PSTs to a relatively narrow CV range allowing development of an LC-ESI-FAIMS-MS method for analysis of PST toxins in complex mussel tissue extracts. The quantitative capabilities of this method were evaluated by analysing a PST containing mussel tissue matrix material. Results compared favourably with analysis by an established LC-post-column oxidation-fluorescence method with recoveries ranging from 70 to 106%, although sensitivity was somewhat reduced. The current work represents the first successful separation of PST isomers using ion mobility and shows the promise of FAIMS as a tool for analysis of algal biotoxins in complex samples and outlines some critical requirements for its future improvement.

  5. Gas molecule scattering & ion mobility measurements for organic macro-ions in He versus N2 environments.

    PubMed

    Larriba-Andaluz, Carlos; Fernández-García, Juan; Ewing, Michael A; Hogan, Christopher J; Clemmer, David E

    2015-06-14

    A pending issue in linking ion mobility measurements to ion structures is that the collisional cross section (CCS, the measured structural parameter in ion mobility spectrometry) of an ion is strongly dependent upon the manner in which gas molecules effectively impinge on and are reemitted from ion surfaces (when modeling ions as fixed structures). To directly examine the gas molecule impingement and reemission processes and their influence, we measured the CCSs of positively charged ions of room temperature ionic liquids 1-ethyl-3-methylimidazolium dicyanamide (EMIM-N(CN)2) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) in N2 using a differential mobility analyzer-mass spectrometer (DMA-MS) and in He using a drift tube mobility spectrometer-mass spectrometer (DT-MS). Cluster ions, generated via electrosprays, took the form (AB)N(A)z, spanning up to z = 20 and with masses greater than 100 kDa. As confirmed by molecular dynamics simulations, at the measurement temperature (∼300 K), such cluster ions took on globular conformations in the gas phase. Based upon their attained charge levels, in neither He nor N2 did the ion-induced dipole potential significantly influence gas molecule-ion collisions. Therefore, differences in the CCSs measured for ions in the two different gases could be primarily attributed to differences in gas molecule behavior upon collision with ions. Overwhelmingly, by comparison of predicted CCSs with selected input impingement-reemission laws to measurements, we find that in N2, gas molecules collide with ions diffusely--they are reemitted at random angles relative to the gas molecule incoming angle--and inelastically. Meanwhile, in He, gas molecules collide specularly and elastically and are emitted from ion surfaces at determined angles. The results can be rationalized on the basis of the momentum transferred per collision; in the case of He, individual gas molecule collisions minimally perturb the atoms within a cluster ion

  6. Gas molecule scattering & ion mobility measurements for organic macro-ions in He versus N2 environments.

    PubMed

    Larriba-Andaluz, Carlos; Fernández-García, Juan; Ewing, Michael A; Hogan, Christopher J; Clemmer, David E

    2015-06-14

    A pending issue in linking ion mobility measurements to ion structures is that the collisional cross section (CCS, the measured structural parameter in ion mobility spectrometry) of an ion is strongly dependent upon the manner in which gas molecules effectively impinge on and are reemitted from ion surfaces (when modeling ions as fixed structures). To directly examine the gas molecule impingement and reemission processes and their influence, we measured the CCSs of positively charged ions of room temperature ionic liquids 1-ethyl-3-methylimidazolium dicyanamide (EMIM-N(CN)2) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) in N2 using a differential mobility analyzer-mass spectrometer (DMA-MS) and in He using a drift tube mobility spectrometer-mass spectrometer (DT-MS). Cluster ions, generated via electrosprays, took the form (AB)N(A)z, spanning up to z = 20 and with masses greater than 100 kDa. As confirmed by molecular dynamics simulations, at the measurement temperature (∼300 K), such cluster ions took on globular conformations in the gas phase. Based upon their attained charge levels, in neither He nor N2 did the ion-induced dipole potential significantly influence gas molecule-ion collisions. Therefore, differences in the CCSs measured for ions in the two different gases could be primarily attributed to differences in gas molecule behavior upon collision with ions. Overwhelmingly, by comparison of predicted CCSs with selected input impingement-reemission laws to measurements, we find that in N2, gas molecules collide with ions diffusely--they are reemitted at random angles relative to the gas molecule incoming angle--and inelastically. Meanwhile, in He, gas molecules collide specularly and elastically and are emitted from ion surfaces at determined angles. The results can be rationalized on the basis of the momentum transferred per collision; in the case of He, individual gas molecule collisions minimally perturb the atoms within a cluster ion

  7. Relating chromatographic retention and electrophoretic mobility to the ion distribution within electrosprayed droplets.

    PubMed

    Bökman, C Fredrik; Bylund, Dan; Markides, Karin E; Sjöberg, Per J R

    2006-03-01

    Ions that are observed in a mass spectrum obtained with electrospray mass spectrometry can be assumed to originate preferentially from ions that have a high distribution to the surface of the charged droplets. In this study, a relation between chromatographic retention and electrophoretic mobility to the ion distribution (derived from measured signal intensities in mass spectra and electrospray current) within electrosprayed droplets for a series of tetraalkylammonium ions, ranging from tetramethyl to tetrapentyl, is presented. Chromatographic retention in a reversed-phase system was taken as a measure of the analyte's surface activity, which was found to have a large influence on the ion distribution within electrosprayed droplets. In addition, different transport mechanisms such as electrophoretic migration and diffusion can influence the surface partitioning coefficient. The viscosity of the solvent system is affected by the methanol content and will influence both diffusion and ion mobility. However, as diffusion and ion mobility are proportional to each other, we have, in this study, chosen to focus on the ion mobility parameter. It was found that the influence of ion mobility relative to surface activity on the droplet surface partitioning of analyte ions decreases with increasing methanol content. This effect is most probably coupled to the decrease in droplet size caused by the decreased surface tension at increasing methanol content. The same observation was made upon increasing the ionic strength of the solvent system, which is also known to give rise to a decreased initial droplet size. The observed effect of ionic strength on the droplet surface partitioning of analyte ions could also be explained by the fact that at higher ionic strength, a larger number of ions are initially closer to the droplet surface and, thus, the contribution of ionic transport from the bulk liquid to the liquid/air surface interface (jet and droplet surface), attributable to

  8. Theoretical evaluation of peak capacity improvements by use of liquid chromatography combined with drift tube ion mobility-mass spectrometry.

    PubMed

    Causon, Tim J; Hann, Stephan

    2015-10-16

    In the domain of liquid phase separations, the quality of separation obtainable is most readily gauged by consideration of classical chromatographic peak capacity theory. Column-based multidimensional strategies for liquid chromatography remain the most attractive and practical route for increasing the number of spatially resolved components in order to reduce stress on necessary mass spectrometric detection. However, the stress placed on a chromatographic separation step as a second dimension in a comprehensive online methodology (i.e. online LC×LC) is rather high. As an alternative to online LC×LC combinations, coupling of HPLC with ion mobility spectrometry hyphenated to mass spectrometry (IMS-MS) has emerged as an attractive approach to permit comprehensive sampling of first dimension chromatographic peaks and subsequent introduction to an orthogonal IMS separation prior to measurement of ions by a mass spectrometer. In the present work, utilization of classical peak capacity and ion mobility theory allows theoretical assessment of the potential of two- (LC×IMS-MS) or even three-dimensional (LC×LC×IMS-MS) experimental setups to enhance peak capacity and, therefore, the number of correctly annotated features within the framework of complex, non-targeted analysis problems frequently addressed using HPLC-MS strategies. Theoretical calculations indicate that newly-available drift tube IMS-MS instrumentation can yield peak capacities of between 10 and 40 using nitrogen drift gas for typical non-targeted metabolomic, lipidomic and proteomic applications according to the expected reduced mobilities of components in the respective samples. Theoretically, this approach can significantly improve the overall peak capacity of conventional HPLC-(MS) methodologies to in excess of 10(4) depending upon the column length and gradient time employed. A more elaborate combination of LC×LC×IMS-MS would improve the ion suppression limitation and possibly allow access to

  9. Theoretical evaluation of peak capacity improvements by use of liquid chromatography combined with drift tube ion mobility-mass spectrometry.

    PubMed

    Causon, Tim J; Hann, Stephan

    2015-10-16

    In the domain of liquid phase separations, the quality of separation obtainable is most readily gauged by consideration of classical chromatographic peak capacity theory. Column-based multidimensional strategies for liquid chromatography remain the most attractive and practical route for increasing the number of spatially resolved components in order to reduce stress on necessary mass spectrometric detection. However, the stress placed on a chromatographic separation step as a second dimension in a comprehensive online methodology (i.e. online LC×LC) is rather high. As an alternative to online LC×LC combinations, coupling of HPLC with ion mobility spectrometry hyphenated to mass spectrometry (IMS-MS) has emerged as an attractive approach to permit comprehensive sampling of first dimension chromatographic peaks and subsequent introduction to an orthogonal IMS separation prior to measurement of ions by a mass spectrometer. In the present work, utilization of classical peak capacity and ion mobility theory allows theoretical assessment of the potential of two- (LC×IMS-MS) or even three-dimensional (LC×LC×IMS-MS) experimental setups to enhance peak capacity and, therefore, the number of correctly annotated features within the framework of complex, non-targeted analysis problems frequently addressed using HPLC-MS strategies. Theoretical calculations indicate that newly-available drift tube IMS-MS instrumentation can yield peak capacities of between 10 and 40 using nitrogen drift gas for typical non-targeted metabolomic, lipidomic and proteomic applications according to the expected reduced mobilities of components in the respective samples. Theoretically, this approach can significantly improve the overall peak capacity of conventional HPLC-(MS) methodologies to in excess of 10(4) depending upon the column length and gradient time employed. A more elaborate combination of LC×LC×IMS-MS would improve the ion suppression limitation and possibly allow access to

  10. New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations

    SciTech Connect

    Bartsch, Richard A.

    2012-06-04

    The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be performed. A unifying feature of the ligand structures is the presence of one (or more) side arm with a pendent acidic function. When a metal ion is complexed within the central cavity of the ligand, ionization of the side arm(s) produces the requisite anion(s) for formation of an overall electroneutral complex. This markedly enhances extraction/transport efficiency for separations in which movement of aqueous phase anions of chloride, nitrate, or sulfate into an organic medium would be required. Through systematic structural variations, new ligands have been developed for efficient and selective separations of monovalent metal ions (e.g., alkali metal, silver, and thallium cations) and of divalent metal ion species (e.g., alkaline earth metal, lead, and mercury cations). Research results obtained in these fundamental investigations provide important insight for the design and development of ligands suitable for practical metal ion separation applications.

  11. Gas phase ion chemistry of an ion mobility spectrometry based explosive trace detector elucidated by tandem mass spectrometry.

    PubMed

    Kozole, Joseph; Levine, Lauren A; Tomlinson-Phillips, Jill; Stairs, Jason R

    2015-08-01

    The gas phase ion chemistry for an ion mobility spectrometer (IMS) based explosive detector has been elucidated using tandem mass spectrometry. The IMS system, which is operated with hexachloroethane and isobutyramide reagent gases and an ion shutter type gating scheme, is connected to the atmospheric pressure interface of a triple quadrupole mass spectrometer (MS/MS). Product ion masses, daughter ion masses, and reduced mobility values for a collection of nitro, nitrate, and peroxide explosives measured with the IMS/MS/MS instrument are reported. The mass and mobility data together with targeted isotopic labeling experiments and information about sample composition and reaction environment are leveraged to propose molecular formulas, structures, and ionization pathways for the various product ions. The major product ions are identified as [DNT-H](-) for DNT, [TNT-H](-) for TNT, [RDX+Cl](-) and [RDX+NO2](-) for RDX, [HMX+Cl](-) and [HMX+NO2](-) for HMX, [NO3](-) for EGDN, [NG+Cl](-) and [NG+NO3](-) for NG, [PETN+Cl](-) and [PETN+NO3](-) for PETN, [HNO3+NO3](-) for NH4NO3, [NO2](-) for DMNB, [HMTD-NC3H6O3+H+Cl](-) and [HMTD+H-CH2O-H2O2](+) for HMTD, and [(CH3)3CO2](+) for TATP. In general, the product ions identified for the IMS system studied here are consistent with the product ions reported previously for an ion trap mobility spectrometer (ITMS) based explosive trace detector, which is operated with dichloromethane and ammonia reagent gases and an ion trap type gating scheme. Differences between the explosive trace detectors include the [NG+Cl](-) and [PETN+Cl](-) product ions being major ions in the IMS system compared to minor ions in the ITMS system as well as the major product ion for TATP being [(CH3)3CO2](+) for the IMS system and [(CH3)2CNH2](+) for the ITMS system. PMID:26048817

  12. Gas phase ion chemistry of an ion mobility spectrometry based explosive trace detector elucidated by tandem mass spectrometry.

    PubMed

    Kozole, Joseph; Levine, Lauren A; Tomlinson-Phillips, Jill; Stairs, Jason R

    2015-08-01

    The gas phase ion chemistry for an ion mobility spectrometer (IMS) based explosive detector has been elucidated using tandem mass spectrometry. The IMS system, which is operated with hexachloroethane and isobutyramide reagent gases and an ion shutter type gating scheme, is connected to the atmospheric pressure interface of a triple quadrupole mass spectrometer (MS/MS). Product ion masses, daughter ion masses, and reduced mobility values for a collection of nitro, nitrate, and peroxide explosives measured with the IMS/MS/MS instrument are reported. The mass and mobility data together with targeted isotopic labeling experiments and information about sample composition and reaction environment are leveraged to propose molecular formulas, structures, and ionization pathways for the various product ions. The major product ions are identified as [DNT-H](-) for DNT, [TNT-H](-) for TNT, [RDX+Cl](-) and [RDX+NO2](-) for RDX, [HMX+Cl](-) and [HMX+NO2](-) for HMX, [NO3](-) for EGDN, [NG+Cl](-) and [NG+NO3](-) for NG, [PETN+Cl](-) and [PETN+NO3](-) for PETN, [HNO3+NO3](-) for NH4NO3, [NO2](-) for DMNB, [HMTD-NC3H6O3+H+Cl](-) and [HMTD+H-CH2O-H2O2](+) for HMTD, and [(CH3)3CO2](+) for TATP. In general, the product ions identified for the IMS system studied here are consistent with the product ions reported previously for an ion trap mobility spectrometer (ITMS) based explosive trace detector, which is operated with dichloromethane and ammonia reagent gases and an ion trap type gating scheme. Differences between the explosive trace detectors include the [NG+Cl](-) and [PETN+Cl](-) product ions being major ions in the IMS system compared to minor ions in the ITMS system as well as the major product ion for TATP being [(CH3)3CO2](+) for the IMS system and [(CH3)2CNH2](+) for the ITMS system.

  13. Novel Nanofiber-based Membrane Separators for Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Yanilmaz, Meltem

    Lithium-ion batteries have been widely used in electronic devices including mobile phones, laptop computers, and cameras due to their high specific energy, high energy density, long cycling lifetime, and low self-discharge rate. Nowadays, lithium-ion batteries are finding new applications in electric/hybrid vehicles and energy storage for smart grids. To be used in these new applications, novel battery components are needed so that lithiumion batteries with higher cell performance, better safety, and lower cost can be developed. A separator is an important component to obtain safe batteries and its primary function is to prevent electronic contact between electrodes while regulating cell kinetics and ionic flow. Currently, microporous membranes are the most commonly used separator type and they have good mechanical properties and chemical stability. However, their wettability and thermal stabilities are not sufficient for applications that require high operating temperature and high performance. Due to the superior properties such as large specific surface area, small pore size and high porosity, electrospun nanofiber membranes can be good separator candidate for highperformance lithium-ion batteries. In this work, we focus our research on fabricating nanofiber-based membranes to design new high-performance separators with good thermal stability, as well as superior electrochemical performance compared to microporous polyolefin membranes. To combine the good mechanical strength of PP nonwovens with the excellent electrochemical properties of SiO2/polyvinylidene fluoride (PVDF) composite nanofibers, SiO 2/PVDF composite nanofiber-coated PP nonwoven membranes were prepared. It was found that the addition of SiO2 nanoparticles played an important role in improving the overall performance of these nanofiber-coated nonwoven membranes. Although ceramic/polymer composites can be prepared by encapsulating ceramic particles directly into polymer nanofibers, the performance

  14. Properties of nickel-cadmium separators. [ion exchange membrances

    NASA Technical Reports Server (NTRS)

    Lee, J.

    1977-01-01

    The thickness, moisture content, exchange capacity, tensile strength, diffusion characteristics, stability, and electrical properties are discussed for the 2291 radiation-grafted separator used in military vented nickel cadmium aircraft batteries. A regression analysis of separator resistance as a function of temperature and KOH concentration is included.

  15. Data for Users of Handheld Ion Mobility Spectrometers

    SciTech Connect

    Keith A. Daum; Sandra L. Fox

    2008-05-01

    Chemical detection technology end-user surveys conducted by Idaho National Laboratory (INL) in 2005 and 2007 indicated that first responders believed manufacturers’ claims for instruments sometimes were not supported in field applications, and instruments sometimes did not meet their actual needs. Based on these findings, the Department of Homeland Security (DHS) asked INL to conduct a similar survey for handheld ion mobility spectrometers (IMS), which are used by a broad community of first responders as well as for other applications. To better access this broad community, the INL used the Center for Technology Commercialization, Inc. (CTC), Public Safety Technology Center (PSTC) to set up an online framework to gather information from users of handheld IMS units. This framework (Survey Monkey) was then used to perform an online Internet survey, augmented by e-mail prompts, to get information from first responders and personnel from various agencies about their direct experience with handheld IMS units. Overall, 478 individuals responded to the survey. Of these, 174 respondents actually owned a handheld IMS. Performance and satisfaction data from these 174 respondents are captured in this report. The survey identified the following observations: • The most common IMS unit used by respondents was the Advanced Portable Detector (APD 2000), followed by ChemRae, Sabre 4000, Sabre 2000, Draeger Multi IMS, Chemical Agent Monitor-2, Chemical Agent Monitor, Vapor Tracer, and Vapor Tracer 2. • The primary owners were HazMat teams (20%), fire services (14%), local police (12%), and sheriffs’ departments (9%). • IMS units are seldom used as part of an integrated system for detecting and identifying chemicals but instead are used independently. • Respondents are generally confused about the capabilities of their IMS unit. This is probably a result of lack of training. • Respondents who had no training or fewer than 8 hours were not satisfied with the overall

  16. Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry.

    PubMed

    Bertoletti, Laura; Regazzoni, Luca; Aldini, Giancarlo; Colombo, Raffaella; Abballe, Franco; Caccialanza, Gabriele; De Lorenzi, Ersilia

    2013-04-10

    In this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimised in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate. PMID:23522119

  17. Pulsed discharge ionization source for miniature ion mobility spectrometers

    DOEpatents

    Xu, Jun; Ramsey, J. Michael; Whitten, William B.

    2004-11-23

    A method and apparatus is disclosed for flowing a sample gas and a reactant gas (38, 43) past a corona discharge electrode (26) situated at a first location in an ion drift chamber (24), applying a pulsed voltage waveform comprising a varying pulse component and a dc bias component to the corona discharge electrode (26) to cause a corona which in turn produces ions from the sample gas and the reactant gas, applying a dc bias to the ion drift chamber (24) to cause the ions to drift to a second location (25) in the ion drift chamber (24), detecting the ions at the second location (25) in the drift chamber (24), and timing the period for the ions to drift from the corona discharge electrode to the selected location in the drift chamber.

  18. Adjusting mobility scales of ion mobility spectrometers using 2,6-DtBP as a reference compound.

    PubMed

    Viitanen, A-K; Mauriala, T; Mattila, T; Adamov, A; Pedersen, C S; Mäkelä, J M; Marjamäki, M; Sysoev, A; Keskinen, J; Kotiaho, T

    2008-09-15

    Performance of several time-of-flight (TOF) type ion mobility spectrometers (IMS) was compared in a joint measurement campaign and their mobility scales were adjusted based on the measurements. A standard reference compound 2,6-di-tert butylpyridine (2,6-DtBP) was used to create a single peak ion mobility distribution with a known mobility value. The effective length of the drift tube of each device, considered here as an instrument constant, was determined based on the measurements. Sequentially, two multi-peaked test compounds, DMMP and DIMP, were used to verify the performance of the adjustment procedure in a wider mobility scale. By determining the effective drift tube lengths using 2,6-DtBP, agreement between the devices was achieved. The determination of effective drift tube lengths according to standard reference compound was found to be a good method for instrument inter-comparison. The comparison procedure, its benefits and shortcomings as well as dependency on accuracy of literature value are discussed along with the results.

  19. A Highly Thermostable Ceramic-Grafted Microporous Polyethylene Separator for Safer Lithium-Ion Batteries.

    PubMed

    Zhu, Xiaoming; Jiang, Xiaoyu; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2015-11-01

    The safety concern is a critical obstacle to large-scale energy storage applications of lithium-ion batteries. A thermostable separator is one of the most effective means to construct the safe lithium-ion batteries. Herein, we demonstrate a novel ceramic (SiO2)-grafted PE separator prepared by electron beam irradiation. The separator shows similar thickness and pore structure to the bare separator, while displaying strong dimensional thermostability, as the shrinkage ratio is only 20% even at an elevated temperature of 180 °C. Besides, the separator is highly electrochemically inert, showing no adverse effect on the energy and power output of the batteries. Considering the excellent electrochemical and thermal stability, the SiO2-grafted PE separator developed in this work is greatly beneficial for constructing safer lithium-ion batteries.

  20. An electrospray ionization-ion mobility spectrometer as detector for high- performance liquid chromatography.

    PubMed

    Zühlke, Martin; Riebe, Daniel; Beitz, Toralf; Löhmannsröben, Hans-Gerd; Zenichowski, Karl; Diener, Marc; Linscheid, Michael W

    2015-01-01

    The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 μL mn(-1) and 1500 μL min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet mode. The novel ESI-IM spectrometer tolerates high water contents (≤90%) and electrolyte concentrations up to 10mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 μM for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic Ims.

  1. Waste separation and pretreatment using crystalline silicotitanate ion exchangers

    SciTech Connect

    Tadros, M.E.; Miller, J.E.; Anthony, R.G.

    1997-10-01

    A new class of inorganic ion exchangers called crystalline silicotitanates (CSTs) has been developed jointly by Sandia National Laboratories and Texas A&M University to selectively remove Cs and other radionuclides from a wide spectrum of radioactive defense wastes. The CST exhibits high selectivity and affinity for Cs and Sr under a wide range of conditions. Tests show it can remove part-per-million concentrations of Cs{sup +} from highly alkaline, high-sodium simulated radioactive waste solutions modeled after those at Hanford, Oak Ridge, and Savannah River. The materials exhibit ion exchange properties based on ionic size selectivity. Specifically, crystalline lattice spacing is controlled to be highly selective for Cs ions even in waste streams containing very high (5 to 10 M) concentrations of sodium. The CST technology is being demonstrated with actual waste at several DOE facilities. The use of inorganic ion exchangers. The inorganics are more resistant to chemical, thermal, and radiation degradation. Their high selectivities result in more efficient operations offering the possibility of a simple single-pass operation. In contrast, regenerable organic ion exchangers require additional processing equipment to handle the regeneration liquids and the eluant with the dissolved Cs.

  2. Comparison of Experimental and Calculated Ion Mobilities of Small Molecules in Air

    PubMed Central

    2016-01-01

    Ion mobility spectrometry is a well-known technique for analyzing gases. Examples are military applications, but also safety related applications, for example, for protection of employees in industries working with hazardous gases. In the last 15 years, this technique has been further developed as a tool for structural analysis, for example, in pharmaceutical applications. In particular, the collision cross section, which is related to the mobility, is of interest here. With help of theoretic principles, it is possible to develop molecular models that can be verified by the comparison of their calculated cross sections with experimental data. In this paper, it is analyzed how well the ion trajectory method is suitable to reproduce the measured ion mobility of small organic molecules such as the water clusters forming the positively charged reactant ions, simple aromatic substances, and n-alkanes. PMID:27298751

  3. Mobility and molecular ions of dimethyl methyl phosphonate, methyl salicylate and acetone

    NASA Astrophysics Data System (ADS)

    Nowak, D. M.

    1983-06-01

    The mobilities of positive and negative reactant ions are reported for (H2O)nH(+); (H2O)2O2 and (H2O)2CO3(-) ion clusters. The formation of positive DMMP monomer and dimer is reported, and equilbria molecular reactions are reported. Acetone is reported as forming a dimer at 81 ppb with a reduced mobility (K sub o) of 1.82, Methyl salicylate is shown to form a protonated and hydrated positive monomer. Mixtures of DMMP and methyl salicylate with acetone showed a substantial change in DMMP ion clustering and little or no change in the methyl salicylate mobility spectra. Negative ions were not observed for DMMP, methyl salicylate, acetone and the mixtures under the conditions reported.

  4. Characterization of the explosive triacetone triperoxide and detection by ion mobility spectrometry.

    PubMed

    Buttigieg, Gavin A; Knight, Andrew K; Denson, Stephen; Pommier, Carolyn; Denton, M Bonner

    2003-07-29

    The improvised explosive triacetone triperoxide (TATP) was synthesized and characterized by 1H-nuclear magnetic resonance (NMR), 13C-NMR, Raman and infrared (IR) spectroscopy. Triacetone triperoxide was subsequently analyzed by ion mobility spectrometry (IMS) in positive ion mode, and detected as a cluster of three peaks with a drift time of the most intense peak at 13.06 ms. Triacetone triperoxide was then analyzed after dissolution in toluene, where a dramatic increase in peak intensity was observed, at a flight time of 12.56 ms (K0=2.71 cm2V(-1)s(-1)). Triacetone triperoxide was subsequently analyzed by coupling the ion mobility spectrometer to a triple quadrupole mass spectrometer, where a single peak at m/z of 223 atomic mass units identified the species present in the ion mobility spectra as being triacetone triperoxide.

  5. SEPARATION OF PLUTONIUM FROM AQUEOUS SOLUTIONS BY ION-EXCHANGE

    DOEpatents

    Schubert, J.

    1958-06-01

    A process is described for the separation of plutonium from an aqueous solution of a plutonium salt, which comprises adding to the solution an acid of the group consisting of sulfuric acid, phosphoric acid, and oxalic acid, and mixtures thereof to provide an acid concentration between 0.0001 and 1 M, contacting the resultant solution with a synthetic organic anion exchange resin, and separating the aqueous phase and the resin which contains the plutonium.

  6. Characterization of an Ion Mobility-Multiplexed Collision Induced Dissociation- Tandem Time-of-Flight Mass Spectrometry Approach

    SciTech Connect

    Ibrahim, Yehia M.; Prior, David C.; Baker, Erin Shammel; Smith, Richard D.; Belov, Mikhail E.

    2010-06-01

    The confidence in peptide (and protein) identifications with ion mobility spectrometry time-of-flight mass spectrometry (IMS-TOFMS) is expected to drastically improve with the addition of information from an efficient ion dissociation step prior to MS detection. High throughput IMS-TOFMS analysis imposes a strong need for multiplexed ion dissociation approaches where multiple precursor ions yield complex sets of fragment ions that are often intermingled with each other in both the drift time and m/z domains. We have developed and evaluated a novel approach for collision-induced dissociation (CID) with an IMS-TOFMS instrument. It has been shown that precursor ions activated inside an rf-device with an axial dc-electric field produce abundant fragment ions which are radially confined with the rf-field and collisionally cooled at an elevated pressure, resulting in high CID efficiencies comparable or higher than those measured in triple-quadrupole instruments We have also developed an algorithm for deconvoluting these complex multiplexed tandem MS spectra by clustering both the precursor and fragment ions into the matching drift time profiles and by effectively utilizing high mass measurement accuracy of the TOFMS. In a single IMS separation with a tryptic digest of bovine serum albumin (BSA), we have reliably identified 20 unique peptides using multiplexed CID approach downstream of the IMS separation. Peptides were identified based upon the correlation between the precursor and fragment drift time profiles and by matching the profile representative masses to those of in silico BSA tryptic peptides and their fragments. The false discovery rate (FDR) of peptide identifications from multiplexed MS/MS spectra was less than 1%.

  7. Quantitative detection of benzene in toluene- and xylene-rich atmospheres using high-kinetic-energy ion mobility spectrometry (IMS).

    PubMed

    Langejuergen, Jens; Allers, Maria; Oermann, Jens; Kirk, Ansgar; Zimmermann, Stefan

    2014-12-01

    One major drawback of ion mobility spectrometry (IMS) is the dependence of the response to a certain analyte on the concentration of water or the presence of other compounds in the sample gas. Especially for low proton affine analytes, e.g., benzene, which often exists in mixtures with other volatile organic compounds, such as toluene and xylene (BTX), a time-consuming preseparation is necessary. In this work, we investigate BTX mixtures using a compact IMS operated at decreased pressure (20 mbar) and high kinetic ion energies (HiKE-IMS). The reduced electric field in both the reaction tube and the drift tube can be independently increased up to 120 Td. Under these conditions, the water cluster distribution of reactant ions is shifted toward smaller clusters independent of the water content in the sample gas. Thus, benzene can be ionized via proton transfer from H3O(+) reactant ions. Also, a formation of benzene ions via charge transfer from NO(+) is possible. Furthermore, the time for interaction between ions and neutrals of different analytes is limited to such an extent that a simultaneous quantification of benzene, toluene, and xylene is possible from low ppbv up to several ppmv concentrations. The mobility resolution of the presented HiKE-IMS varies from R = 65 at high field (90 Td) to R = 73 at lower field (40 Td) in the drift tube, which is sufficient to separate the analyzed compounds. The detection limit for benzene is 29 ppbv (2 s of averaging) with 3700 ppmv water, 12.4 ppmv toluene, and 9 ppmv xylene present in the sample gas. Furthermore, a less-moisture-dependent benzene measurement with a detection limit of 32 ppbv with ca. 21 000 ppmv (90% relative humidity (RH) at 20 °C) water present in the sample gas is possible evaluating the signal from benzene ions formed via charge transfer.

  8. Selective separation and determination of isoproterenol on thin layers of bismuth silicate ion-exchanger.

    PubMed

    Ghoulipour Vanik; Hassankhani-Majd Zahra

    2015-06-01

    A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate, a synthetic inorganic ion exchanger as adsorbent in thin layer chromatography (TLC). A mixture of methanol and 0.1 mol/L formic acid (3:7, v/v) was employed as the mobile phase. The development time was 32 min. The quantitative measurement were performed with a Camag TLC Scanner-3 at wavelength (λ) of 410 nm. The isoproterenol recovery in this procedure was 98.9%. The linear correlation coefficient was greater than 0. 987 1 and the relative standard deviation (RSD) was less than 0.94. The limit of detection (LOD) and limit of quantification ( LOQ) were 7.7 x 10(-7) mol/L and 3.85 x 10(-6) mol/L, respectively. This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.

  9. [Separation of zoledronic acid and its related substances by ion-pair reversed-phase high performance liquid chromatography].

    PubMed

    Zhang, Xiaoqing; Jiang, Ye; Xu, Zhiru

    2004-07-01

    A rapid and simple ion-pair reversed-phase high performance liquid chromatographic method (HPLC) has been established for the routine analysis of zoledronic acid and its related substances. The chromatographic conditions were optimized based on the satisfactory separation of zoledronic acid from imidazol-1-ylacetic acid, their retention times and peak shape. The excellent separation of zoledronic acid from its related substances, including the remaining imidazol-1-ylacetic acid used in the synthesis of zoledronic acid and other impurities of oxidation and decomposition, was achieved within 9 min on a Hypersil C8 column with UV detection at 220 nm. The mobile phase was a mixture of methanol (20%) and 5 mmo/L phosphate buffer (80%) that contains 6 mmol/L tetrabutylammonium bromide. The resolution factor of zoledronic acid from its adjacent peak was more than 2.5. This is a simple and rapid method for the routine assay of zoledronic acid.

  10. Isotopic separation of lithium ions by capillary zone electrophoresis.

    PubMed

    Kamencev, Mikhail; Yakimova, Nina; Moskvin, Leonid; Kuchumova, Irina; Tkach, Kirill; Malinina, Yulia; Tungusov, Oleg

    2015-12-01

    Separation of (6)Li and (7)Li isotopes by CZE was demonstrated. The BGE contained 5 mM 4-aminopyridine, 0.9 mM oxalic acid, 0.25 mM CTAB, and 0.25% w/v Tween 20 (рН = 9.2). The running conditions were +25 kV at 30°C with indirect photometric detection at 261 nm. Under optimal experimental conditions, the analysis time was less than 21 min. Separation of Li preparations with mole fraction of (6)Li ranging from 3.44 up to 90.38% was demonstrated.

  11. Ion mobility tandem mass spectrometry enhances performance of bottom-up proteomics.

    PubMed

    Helm, Dominic; Vissers, Johannes P C; Hughes, Christopher J; Hahne, Hannes; Ruprecht, Benjamin; Pachl, Fiona; Grzyb, Arkadiusz; Richardson, Keith; Wildgoose, Jason; Maier, Stefan K; Marx, Harald; Wilhelm, Mathias; Becher, Isabelle; Lemeer, Simone; Bantscheff, Marcus; Langridge, James I; Kuster, Bernhard

    2014-12-01

    One of the limiting factors in determining the sensitivity of tandem mass spectrometry using hybrid quadrupole orthogonal acceleration time-of-flight instruments is the duty cycle of the orthogonal ion injection system. As a consequence, only a fraction of the generated fragment ion beam is collected by the time-of-flight analyzer. Here we describe a method utilizing postfragmentation ion mobility spectrometry of peptide fragment ions in conjunction with mobility time synchronized orthogonal ion injection leading to a substantially improved duty cycle and a concomitant improvement in sensitivity of up to 10-fold for bottom-up proteomic experiments. This enabled the identification of 7500 human proteins within 1 day and 8600 phosphorylation sites within 5 h of LC-MS/MS time. The method also proved powerful for multiplexed quantification experiments using tandem mass tags exemplified by the chemoproteomic interaction analysis of histone deacetylases with Trichostatin A.

  12. Identity Efficiency for High-Performance Ambient Pressure Ion Mobility Spectrometry.

    PubMed

    Kanu, A Bakarr; Leal, Anne

    2016-03-15

    A new approach to reduce the false-positive responses commonly encountered in the field when drugs and explosives are detected is reported for an electrospray ionization high-performance ion mobility spectrometry (ESI-HPIMS). In this article, we report on the combination of reduced mobility and the width-at-half-height of a peak to give a new parameter called conditional reduced mobility (CRM). It was found that the CRM was capable of differentiating between real drugs peaks from that of a false-positive peak and may help to reduce false-positive rates. This effect was demonstrated using 11 drugs (amphetamine, cannabidiol, cocaine, codeine, heroine, methamphetamine, morphine, phentermine, L-phenylepherine, proglitazone, and rosiglitazone) and seven interferences chosen from off-the-shelf products. This report determined and compared CRM, resolving power (R(m)), and diffusion-limited conditional theoretical reduced mobility (DLCTRM) for ESI-HPIMS. The most important parameters for determining CRM are reduced mobility and width-at-half-height of a peak. There is a specific optimum voltage, gate pulse width, resolving power, and now CRM for each ion. DLCTRM indicate the optimum reduced mobility that is not normally possible under field conditions. CRM predicts the condition at which a target compound can be differentiated from a false-positive response. This was possible because different ions exhibits different drifting patterns and hence a different peak broadening phenomenon inside an ion mobility tube. Reduced mobility for target compounds reported were reproducible to within 2% for ESI-HPIMS. The estimated resolving power for the ESI-HPIMS used in this study was 61 ± 0.22. Conditional reduced mobility introduced in this paper show differences between target compounds and false-positive peaks as high as 74%, as was the case for cannabidiol and interference #1 at 70 μs gate pulse width. PMID:26919030

  13. Identity Efficiency for High-Performance Ambient Pressure Ion Mobility Spectrometry.

    PubMed

    Kanu, A Bakarr; Leal, Anne

    2016-03-15

    A new approach to reduce the false-positive responses commonly encountered in the field when drugs and explosives are detected is reported for an electrospray ionization high-performance ion mobility spectrometry (ESI-HPIMS). In this article, we report on the combination of reduced mobility and the width-at-half-height of a peak to give a new parameter called conditional reduced mobility (CRM). It was found that the CRM was capable of differentiating between real drugs peaks from that of a false-positive peak and may help to reduce false-positive rates. This effect was demonstrated using 11 drugs (amphetamine, cannabidiol, cocaine, codeine, heroine, methamphetamine, morphine, phentermine, L-phenylepherine, proglitazone, and rosiglitazone) and seven interferences chosen from off-the-shelf products. This report determined and compared CRM, resolving power (R(m)), and diffusion-limited conditional theoretical reduced mobility (DLCTRM) for ESI-HPIMS. The most important parameters for determining CRM are reduced mobility and width-at-half-height of a peak. There is a specific optimum voltage, gate pulse width, resolving power, and now CRM for each ion. DLCTRM indicate the optimum reduced mobility that is not normally possible under field conditions. CRM predicts the condition at which a target compound can be differentiated from a false-positive response. This was possible because different ions exhibits different drifting patterns and hence a different peak broadening phenomenon inside an ion mobility tube. Reduced mobility for target compounds reported were reproducible to within 2% for ESI-HPIMS. The estimated resolving power for the ESI-HPIMS used in this study was 61 ± 0.22. Conditional reduced mobility introduced in this paper show differences between target compounds and false-positive peaks as high as 74%, as was the case for cannabidiol and interference #1 at 70 μs gate pulse width.

  14. Radio-frequency ion deflector for mass separation

    SciTech Connect

    Schlösser, Magnus Rudnev, Vitaly; Ureña, Ángel González

    2015-10-15

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

  15. Radio-frequency ion deflector for mass separation.

    PubMed

    Schlösser, Magnus; Rudnev, Vitaly; González Ureña, Ángel

    2015-10-01

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated. PMID:26520948

  16. Electrophoretic mobility as a tool to separate immune adjuvant saponins from Quillaja saponaria Molina.

    PubMed

    Gilabert-Oriol, Roger; Weng, Alexander; von Mallinckrodt, Benedicta; Stöshel, Anja; Nissi, Linda; Melzig, Matthias F; Fuchs, Hendrik; Thakur, Mayank

    2015-06-20

    Quillaja saponins are used as adjuvants in animal vaccines but their application in human vaccination is still under investigation. Isolation and characterization of adjuvant saponins is very tedious. Furthermore, standardization of Quillaja saponins is critical pertaining to its application in humans. In this study, a convenient method based on agarose gel electrophoresis was developed for the separation of Quillaja saponins. Six different commercial Quillaja saponins were segregated by size/charge into numerous fractions. Each of the fractions was characterized by ESI-TOF-MS spectroscopy and thin layer chromatography. Real-time impedance-based monitoring and red blood cell lysis assay were used to evaluate cytotoxicity and hemolytic activities respectively. Two specific regions in the agarose gel (delimited by specific relative electrophoretic mobility values) were identified and characterized by exclusive migration of acylated saponins known to possess immune adjuvant properties (0.18-0.58), and cytotoxic and hemolytic saponins (0.18-0.94). In vivo experiments in mice with the isolated fractions for evaluation of adjuvant activity also correlated with the relative electrophoretic mobility. In addition to the separation of specific Quillaja saponins with adjuvant effects as a pre-purification step to HPLC, agarose gel electrophoresis stands out as a new method for rapid screening, separation and quality control of saponins. PMID:25839418

  17. Modeling of ion transport through a porous separator in vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Zhou, X. L.; Zhao, T. S.; An, L.; Zeng, Y. K.; Wei, L.

    2016-09-01

    In this work, we develop a two-dimensional, transient model to investigate the mechanisms of ion-transport through a porous separator in VRFBs and their effects on battery performance. Commercial-available separators with pore sizes of around 45 nm are particularly investigated and effects of key separator design parameters and operation modes are explored. We reveal that: i) the transport mechanism of vanadium-ion crossover through available separators is predominated by convection; ii) reducing the pore size below 15 nm effectively minimizes the convection-driven vanadium-ion crossover, while further reduction in migration- and diffusion-driven vanadium-ion crossover can be achieved only when the pore size is reduced to the level close to the sizes of vanadium ions; and iii) operation modes that can affect the pressure at the separator/electrode interface, such as the electrolyte flow rate, exert a significant influence on the vanadium-ion crossover rate through the available separators, indicating that it is critically important to equalize the pressure on each half-cell of a power pack in practical applications.

  18. Determination of Benzene, Toluene, and Xylene by means of an ion mobility spectrometer device using photoionization

    NASA Technical Reports Server (NTRS)

    Leonhardt, J. W.; Bensch, H.; Berger, D.; Nolting, M.; Baumbach, J. I.

    1995-01-01

    The continuous monitoring of changes on the quality of ambient air is a field of advantage of ion mobility spectrometry. Benzene, Toluene, and Xylene are substances of special interest because of their toxicity. We present an optimized drift tube for ion mobility spectrometers, which uses photo-ionization tubes to produce the ions to be analyzed. The actual version of this drift tube has a length of 45 mm, an electric field strength established within the drift tube of about 180 V/cm and a shutter-opening-time of 400 mus. With the hydrogen tube used for ionisation a mean flux of 10(exp 12) photons/sq cm s was established for the experiments described. We discuss the results of investigations on Benzene, Toluene, and Xylene in normal used gasoline SUPER. The detection limits obtained with the ion mobility spectrometer developed in co-operation are in the range of 10 ppbv in this case. Normally, charge transfer from Benzene ions to Toluene takes place. Nevertheless the simultaneous determination in mixtures is possible by a data evaluation procedure developed for this case. The interferences found between Xylene and others are rather weak. The ion mobility spectra of different concentrations of gasoline SUPER are attached as an example for the resolution and the detection limit of the instrument developed. Resolution and sensitivity of the system are well demonstrated. A hand-held portable device produced just now is to be tested for special environmental analytical problems in some industrial and scientific laboratories in Germany.

  19. Effects of ion mobility and positron fraction on solitary waves in weak relativistic electron-positron-ion plasma.

    PubMed

    Lu, Ding; Li, Zi-Liang; Xie, Bai-Song

    2013-09-01

    The effects of ion mobility and positron fraction on the solitary waves of the laser field envelope and the potential of the electrostatic field in weak relativistic electron-positron-ion plasma are investigated. The parameter region for the existence of solitary waves is obtained analytically, and a reasonable choice of parameters is clarified. Both cases of mobile and immobile ions are considered. It is found that the amplitudes of solitary waves in the former case are larger compared to the latter case. For small plasma density, the localized solitary wave solutions in terms of the approximate perturbation analytical method are very consistent with those by exact numerical calculations. However, as the plasma density increases the analytical method loses its validity more and more. The influence of the positron fraction on the amplitudes of solitary waves shows a monotonous increasing relation. The implications of our results to particle acceleration are also discussed briefly. PMID:24125373

  20. High-Field Asymmetric-Waveform Ion Mobility Spectrometry and Electron Detachment Dissociation of Isobaric Mixtures of Glycosaminoglycans

    NASA Astrophysics Data System (ADS)

    Kailemia, Muchena J.; Park, Melvin; Kaplan, Desmond A.; Venot, Andre; Boons, Geert-Jan; Li, Lingyun; Linhardt, Robert J.; Amster, I. Jonathan

    2013-11-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is shown to be capable of resolving isomeric and isobaric glycosaminoglycan negative ions and to have great utility for the analysis of this class of molecules when combined with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tandem mass spectrometry. Electron detachment dissociation (EDD) and other ion activation methods for tandem mass spectrometry can be used to determine the sites of labile sulfate modifications and for assigning the stereochemistry of hexuronic acid residues of glycosaminoglycans (GAGs). However, mixtures with overlapping mass-to-charge values present a challenge, as their precursor species cannot be resolved by a mass analyzer prior to ion activation. FAIMS is shown to resolve two types of mass-to-charge overlaps. A mixture of chondroitin sulfate A (CSA) oligomers with 4-10 saccharides units produces ions of a single mass-to-charge by electrospray ionization, as the charge state increases in direct proportion to the degree of polymerization for these sulfated carbohydrates. FAIMS is shown to resolve the overlapping charge. A more challenging type of mass-to-charge overlap occurs for mixtures of diastereomers. FAIMS is shown to separate two sets of epimeric GAG tetramers. For the epimer pairs, the complexity of the separation is reduced when the reducing end is alkylated, suggesting that anomers are also resolved by FAIMS. The resolved components were activated by EDD and the fragment ions were analyzed by FTICR-MS. The resulting tandem mass spectra were able to distinguish the two epimers from each other.

  1. Calcium Activities During Different Ion Exchange Separation Procedures

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Zhu, H.; Liu, Y.; Liu, F.; Zhang, C.; Sun, W.

    2014-12-01

    Calcium is a major element and participates in many geological processes. Investigations on stable calcium isotopic compositions of natural geological samples provide a great powerful tool to understand all kinds of those geological processes from a view of the field of isotope geochemistry. With the development of modern instruments and chemical separation techniques, calcium isotopic compositions could be determined even more precisely if the column chemistry brings no deviation. Usually, Calcium is separated from matrix elements using cation resin columns and the related chemical separation techniques seem to be robust. However, more detailed work still need to be done on matrix effects and calcium isotopic fractionations on column chemistry or during elution processes. If calcium is run on TIMS instruments, the interference effect could be lower and easier controlled, thus, the requirement to the chemistry is relatively not critic, but calcium fractionation on filaments could be much difficult to monitor. If calcium is run on MC-ICP-MS instruments, the interference effect could be huge and is really difficult to be recognized and subtracted, the requirement to the chemistry is much more critical in order to get a real result of the sample, but the instrument fractionation could be easier to monitor. Here we investigate calcium activities on several kinds of cation resins under different column/acid conditions. We seek to find a good balance between recovery and interference effect on column chemistry and are intend to set up a better chemical separation procedure to satisfy the instrument requirements for calcium. In addition, Calcium isotopic fractionation on column will also be discussed further here based on our previous and ongoing results.

  2. Method for mobilization of hazardous metal ions in soils

    DOEpatents

    Dugan, Patrick R.; Pfister, Robert M.

    1995-01-01

    A microbial process for removing heavy metals such as bismuth, cadmium, lead, thorium, uranium and other transuranics from soils and sediments, utilizing indigenous, or isolates of indigenous, microorganisms and reducing agents, such as cysteine or sodium thioglycollate, or complexing agents such as the amino acid glycine, to effect the mobilization or release of the metals from the soil particles.

  3. High Resolution Separations and Improved Ion Production and Transmission in Metabolomics

    SciTech Connect

    Metz, Thomas O.; Page, Jason S.; Baker, Erin Shammel; Tang, Keqi; Ding, Jie; Shen, Yufeng; Smith, Richard D.

    2008-03-31

    The goal of metabolomics experiments is the detection and quantitation of as many sample components as reasonably possible in order to identify “features” that can be used to characterize the samples under study. When utilizing electrospray ionization to produce ions for analysis by mass spectrometry (MS), it is imperative that metabolome sample constituents be efficiently separated prior to ion production, in order to minimize the phenomenon of ionization suppression. Similarly, optimization of the MS inlet can lead to increased measurement sensitivity. This review will focus on the role of high resolution liquid chromatography (LC) separations in conjunction with improved ion production and transmission for LC-MS-based metabolomics.

  4. Facilitated ion diffusion in multiscale porous particles: application in battery separators.

    PubMed

    Kim, Young Bum; Tran-Phu, Thanh; Kim, Min; Jung, Dae-Woong; Yi, Gi-Ra; Park, Jong Hyeok

    2015-03-01

    Polyethylene (PE) separators have been the most popular option for commercial Li-ion batteries because of their uniform pore size, high tensile strength, low cost, and electrochemical stability. Unfortunately, PE separators generally suffer from significant dimensional changes at high temperatures, which frequently results in serious safety problems. In this regard, the integration of inorganic nanoparticles with PE separators has been considered to be a promising approach. Here, inorganic nanoparticles with a hierarchical pore structure were coated on a conventional polymer separator. The resultant composite separator exhibited superior Li ion transportation compared with separators coated with mesopore-only nanoparticles or conventional nonporous nanoparticles. The mesopores and macropores act synergistically to improve the electrolyte uptake and ionic conductivity of the inorganic nanoparticles, while other positive aspects such as their thermal and mechanical properties are still maintained.

  5. Investigation of mass transfer in the ion-exchange-membrane-partitioned free-flow IEF system for protein separation.

    PubMed

    Cheng, Jiu-Hua; Chung, Tai Shung; Neo, Sok Hong

    2009-08-01

    In this study, novel polysulfone-based cation-exchange membranes with strong mechanical strength have been developed and applied in ion-exchange-membrane-partitioned free-flow IEF (IEM-FFIEF) to replace the conventional immobiline membranes. A fundamental understanding of protein mass transfer in the IEM-FFIEF process has been revealed experimentally with the aid of membrane-based boundary effect model contributed by Ennis et al. we have proven experimentally the existence of a pH gradient across the membrane cross-section when an IEM-FFIEF system is in operation. The boundary effects on particle velocities are calculated based on the IEF assumption and various characterizations, and are compared with the experimental results. In the IEM-FFIEF experiments, a protein mixture (BSA and myoglobin (Mb)) and sulfonated polysulfone membranes with different ion-exchange capacities are applied. Experimental results show that the real velocity and real mobility (of Mb in this study) are comparable with the mathematic model developed by Ennis et al. This suggests that the equation proposed by Ennis et al., is sufficient to capture the mass transfer through membrane in the IEM-FFIEF system after considering the effects of pore size distribution and effects of disturbed electric field. The charge properties of the membrane surface play a dominant role on the separation performance of the membranes. The newly developed porous solid-phase ion-exchange membranes may potentially and effectively replace immobilines to perform the selective function for protein separation.

  6. Bacterial cellulose nanofibrous membrane as thermal stable separator for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Jiang, Fengjing; Yin, Lei; Yu, Qingchun; Zhong, Chunyan; Zhang, Junliang

    2015-04-01

    Thermal shrinkage is a severe problem for the conventional polyolefin separators. In this work, we report the excellent performance of bacterial cellulose (BC) nanofibrous membranes as separators for lithium (Li) ion batteries. Properties of BC separator including morphology, ionic conductivity, electrochemical stability, thermal stability, mechanical strength and battery charge-discharge performance are characterized and compared to a commercial separator membrane (Celgard® 2325). Because of the unique fibrous and cross-linked three-dimensional network structure, BC separator shows excellent dimensional stability up to 180 °C, good ionic conductivity and competitive battery performance.

  7. Magnetic separation of Dy(III) ions from homogeneous aqueous solutions

    SciTech Connect

    Pulko, B. Yang, X.; Lei, Z.; Odenbach, S.; Eckert, K.

    2014-12-08

    The possibility to enrich paramagnetic dysprosium(III) ions in a magnetic field gradient is proved by means of interferometry, which may open the route for a magnetic separation of rare earth ions from aqueous solutions. The separation dynamics are studied for three different concentrations of DyCl{sub 3} and compared with those found recently in a sulphate solution of the 3d ion Mn(II). In view of the similar-sized hydration spheres for Dy(III) and Mn(II), the slower separation dynamics in DyCl{sub 3} is attributed to both a higher densification coefficient and the strong impact of Brownian motion due to the absence of ion-pair clusters.

  8. Method and apparatus for compressing ions

    DOEpatents

    Garimella, Sandilya V. B.; Ibrahim, Yehia M.; Anderson, Gordon A.; Smith, Richard D.

    2015-06-23

    A method and apparatus for compressing ions inside an ion mobility device is disclosed. Ions are introduced into the mobility device. The ions are subjected to a non-constant electric field to form a potential gradient along a portion of the device so that ions with similar mobilities bunch together into sharper peaks while maintaining separation between other ions. The potential gradient progressively increases or decreases along the length of the device.

  9. Method and system for producing hydrogen using sodium ion separation membranes

    SciTech Connect

    Bingham, Dennis N; Klingler, Kerry M; Turner, Terry D; Wilding, Bruce M; Frost, Lyman

    2013-05-21

    A method of producing hydrogen from sodium hydroxide and water is disclosed. The method comprises separating sodium from a first aqueous sodium hydroxide stream in a sodium ion separator, feeding the sodium produced in the sodium ion separator to a sodium reactor, reacting the sodium in the sodium reactor with water, and producing a second aqueous sodium hydroxide stream and hydrogen. The method may also comprise reusing the second aqueous sodium hydroxide stream by combining the second aqueous sodium hydroxide stream with the first aqueous sodium hydroxide stream. A system of producing hydrogen is also disclosed.

  10. Separation of zinc and nickel ions in a strong acid through liquid-liquid extraction.

    PubMed

    Park, Young Jun; Fray, Derek J

    2009-04-15

    Many solid wastes contain both zinc and nickel at the same time. For recycling or recovery of metals, it is essential to separate materials. Among those materials, zinc and nickel are very difficult to be separated because there is not so much difference in the chemical and physical properties. This paper focuses on the separation of zinc and nickel ions in a diluted aqua regia solution. Liquid-liquid extraction by TBP, Cyanex 272 and Cyanex 301 was used and a distribution coefficient (D), a separation factor (S) and a relative purity (R) were induced to evaluate the degree of separation. All of the extractions were proportional to the concentration of the extractants, and zinc ions were extracted more easily than nickel ions. Among the extractants, Cyanex 301 showed the best characteristics regarding Zn/Ni separation. In particular, the extraction of zinc ions in the range of pHions was less than 20 wt.%, when 100 vol.% Cyanex 301 was used. The maximum S(Zn,Ni) value was about 21,700 at pH 6.0 and the highest relative purity (R) of zinc was about 99 wt.% without a pH control, pH -1.1. PMID:18675511

  11. Photo and Collision Induced Isomerization of a Cyclic Retinal Derivative: An Ion Mobility Study

    NASA Astrophysics Data System (ADS)

    Coughlan, Neville J. A.; Scholz, Michael S.; Hansen, Christopher S.; Trevitt, Adam J.; Adamson, Brian D.; Bieske, Evan J.

    2016-09-01

    A cationic degradation product, formed in solution from retinal Schiff base (RSB), is examined in the gas phase using ion mobility spectrometry, photoisomerization action spectroscopy, and collision induced dissociation (CID). The degradation product is found to be N- n-butyl-2-(β-ionylidene)-4-methylpyridinium (BIP) produced through 6π electrocyclization of RSB followed by protonation and loss of dihydrogen. Ion mobility measurements show that BIP exists as trans and cis isomers that can be interconverted through buffer gas collisions and by exposure to light, with a maximum response at λ = 420 nm.

  12. Photo and Collision Induced Isomerization of a Cyclic Retinal Derivative: An Ion Mobility Study.

    PubMed

    Coughlan, Neville J A; Scholz, Michael S; Hansen, Christopher S; Trevitt, Adam J; Adamson, Brian D; Bieske, Evan J

    2016-09-01

    A cationic degradation product, formed in solution from retinal Schiff base (RSB), is examined in the gas phase using ion mobility spectrometry, photoisomerization action spectroscopy, and collision induced dissociation (CID). The degradation product is found to be N-n-butyl-2-(β-ionylidene)-4-methylpyridinium (BIP) produced through 6π electrocyclization of RSB followed by protonation and loss of dihydrogen. Ion mobility measurements show that BIP exists as trans and cis isomers that can be interconverted through buffer gas collisions and by exposure to light, with a maximum response at λ = 420 nm.Graphical Abstract.

  13. Determining the mobility of ions by transient current measurements at high voltages.

    PubMed

    Kohn, Peter; Schröter, Klaus; Thurn-Albrecht, Thomas

    2007-08-24

    We present polarization and transient current experiments that allow an independent determination of the charge carrier density and the mobility of ions in polymer electrolytes at low charge carrier density. The method relies on a complete depletion of ions in the bulk electrolyte achieved by applying high voltages. Based on a qualitative model for the charge dynamics in this nonlinear regime, the method is exemplarily applied to a system of polymethylmethacrylate doped with small amounts of a lithium salt. The independently obtained values for the ionic mobility, the charge carrier density, and the conductivity are consistent for all salt concentrations studied. Criteria for the applicability of the method are discussed.

  14. Electron attachment rate constant measurement by photoemission electron attachment ion mobility spectrometry (PE-EA-IMS)

    NASA Astrophysics Data System (ADS)

    Su, Desheng; Niu, Wenqi; Liu, Sheng; Shen, Chengyin; Huang, Chaoqun; Wang, Hongmei; Jiang, Haihe; Chu, Yannan

    2012-12-01

    Photoemission electron attachment ion mobility spectrometry (PE-EA-IMS), with a source of photoelectrons induced by vacuum ultraviolet radiation on a metal surface, has been developed to study electron attachment reaction at atmospheric pressure using nitrogen as the buffer gas. Based on the negative ion mobility spectra, the rate constants for electron attachment to tetrachloromethane and chloroform were measured at ambient temperature as a function of the average electron energy in the range from 0.29 to 0.96 eV. The experimental results are in good agreement with the data reported in the literature.

  15. Electrode-supported thin α-alumina separators for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Mi, Wanliang; Sharma, Gaurav; Dong, Xueliang; Jin, Yi; Lin, Y. S.

    2016-02-01

    Lithium ion batteries with an inorganic separator offer improved safety and enhanced reliability. The free-standing inorganic separators recently studied for lithium ion batteries are brittle and expensive. To address these issues, this paper reports the synthesis of a new and stable electrode-supported separator using a low-cost ceramic powder. Thin and porous α-Al2O3 separator films of thicknesses down to 40 μm were coated on Li4Ti5O12 (LTO) electrode by blade-coating a slurry of α-Al2O3, water and a small amount of polyvinyl alcohol (PVA). The performance of the LTO/Li cells with coated α-Al2O3 separator improves with decreasing PVA content. Cells with coated α-Al2O3 separator containing 0.4wt% PVA exhibit similar discharge capacity but better rate capability than those with commercial polypropylene (PP) or thick sintered α-Al2O3 separator. The coated α-Al2O3 separator does not react with LTO even after many charge/discharge cycles. Fabrication of the electrode-supported α-Al2O3 separator is scalable and cost-effective, offering high potential for practical application in industrial lithium ion battery manufacturing.

  16. Interfacing an ion mobility spectrometry based explosive trace detector to a triple quadrupole mass spectrometer.

    PubMed

    Kozole, Joseph; Stairs, Jason R; Cho, Inho; Harper, Jason D; Lukow, Stefan R; Lareau, Richard T; DeBono, Reno; Kuja, Frank

    2011-11-15

    Hardware from a commercial-off-the-shelf (COTS) ion mobility spectrometry (IMS) based explosive trace detector (ETD) has been interfaced to an AB/SCIEX API 2000 triple quadrupole mass spectrometer. To interface the COTS IMS based ETD to the API 2000, the faraday plate of the IMS instrument and the curtain plate of the mass spectrometer were removed from their respective systems and replaced by a custom faraday plate, which was fabricated with a hole for passing the ion beam to the mass spectrometer, and a custom interface flange, which was designed to attach the IMS instrument onto the mass spectrometer. Additionally, the mass spectrometer was modified to increase the electric field strength and decrease the pressure in the differentially pumped interface, causing a decrease in the effect of collisional focusing and permitting a mobility spectrum to be measured using the mass spectrometer. The utility of the COTS-ETD/API 2000 configuration for the characterization of the gas phase ion chemistry of COTS-ETD equipment was established by obtaining mass and tandem mass spectra in the continuous ion flow and selected mobility monitoring operating modes and by obtaining mass-selected ion mobility spectra for the explosive standard 2,4,6 trinitrotoluene (TNT). This analysis confirmed that the product ion for TNT is [TNT - H](-), the predominant collision-induced dissociation pathway for [TNT- H](-) is the loss of NO and NO(2), and the reduced mobility value for [TNT - H](-) is 1.54 cm(2)V(-1) s(-1). Moreover, this analysis was attained for sample amounts of 1 ng and with a resolving power of 37. The objective of the research is to advance the operational effectiveness of COTS IMS based ETD equipment by developing a platform that can facilitate the understanding of the ion chemistry intrinsic to the equipment.

  17. Electrodialysis-ion exchange for the separation of dissolved salts

    SciTech Connect

    Baroch, C.J.; Grant, P.J.

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

  18. Electrodialysis-ion exchange for the separation of dissolved salts

    SciTech Connect

    Baroch, C.J.; Grant, P.J.

    1995-12-31

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. This report describes the process of electrodialysis-ion exchange (EDIX) for treating aqueous wastes streams consisting of nitrates, sodium, organics, heavy metals, and radioactive species.

  19. Free ion yields, electron thermalization distances, and ion mobilities in liquid cyclic hydrocarbons: Cyclohexane and trans- and cis-decalin

    NASA Astrophysics Data System (ADS)

    Gee, Norman; Freeman, Gordon R.

    1992-01-01

    Free ion yields GEfi were measured as a function of electric field strength E in liquids of the cyclic hydrocarbons cyclohexane, trans-decalin, and cis-decalin at temperatures up to 514, 386, and 372 K, respectively. By comparing the measured GEfi to values calculated using the extended Onsager model, zero-field free ion yields G0fi and thermalization distances bGP were obtained. The values of G0fi in trans-decalin were used to correct previously reported values of the electron mobility obtained using estimates of G0fi. Values of the density-normalized thermalization distances bGPd were ˜9% higher than in the linear n-alkanes, that is, at a given reduced density d/dc, energy transfer from the thermalizing electron is less efficient than to the n-alkanes. Measured molecular cation mobilities μ+ were correlated with liquid viscosity and compared with neutral molecule diffusion coefficients. The mobility of the molecular cations was three to four times smaller than that of the corresponding neutral molecules. A free volume model was used to describe the temperature dependence of μ+. Ion transport in a liquid is made easier by increasing the free volume of the liquid, which occurs when it is heated under its vapor pressure. The amount of thermal energy required to activate the actual transport of the ions is considerably smaller than suggested by the Arrhenius model.

  20. A novel approach for enhancing metal ion separation using acoustic nebulisation.

    PubMed

    Jimmy, Beenamma; Kolev, Spas D; Kentish, Sandra; Ashokkumar, Muthupandian

    2012-05-01

    A novel technique for anionic surfactant assisted separation and preconcentration of metal cations was developed using ultrasound induced nebulization at MHz frequency. The ions of copper, zinc, cadmium, and calcium were used as model analytes. Analysis of the aerosol using flame atomic absorption spectrometry showed enrichment factors for the metal ions studied between 5 and 8, when dilute solutions containing sodium dodecylsulfate and the metal ions were nebulized. The mechanism of metal ion enrichment was explained based on surfactant adsorption and the droplet model for aerosol droplets. It was demonstrated that further increase in the enrichment factor could be achieved by increasing the ultrasound frequency, thus producing smaller droplets. PMID:22154732

  1. Effect of mobile ions on the electric field needed to orient charged diblock copolymer thin films

    SciTech Connect

    Dehghan, Ashkan; Shi, An-Chang; Schick, M.

    2015-10-07

    We examine the behavior of lamellar phases of charged/neutral diblock copolymer thin films containing mobile ions in the presence of an external electric field. We employ self-consistent field theory and focus on the aligning effect of the electric field on the lamellae. Of particular interest are the effects of the mobile ions on the critical field, the value required to reorient the lamellae from the parallel configuration favored by the surface interaction to the perpendicular orientation favored by the field. We find that the critical field depends strongly on whether the neutral or charged species is favored by the substrates. In the case in which the neutral species is favored, the addition of charges decreases the critical electric field significantly. The effect is greater when the mobile ions are confined to the charged lamellae. In contrast, when the charged species is favored by the substrate, the addition of mobile ions stabilizes the parallel configuration and thus results in an increase in the critical electric field. The presence of ions in the system introduces a new mixed phase in addition to those reported previously.

  2. Method for mobilization of hazardous metal ions in soils

    DOEpatents

    Dugan, P.R.; Pfister, R.M.

    1995-06-27

    A microbial process is revealed for removing heavy metals such as bismuth, cadmium, lead, thorium, uranium and other transuranics from soils and sediments. The method utilizes indigenous, or isolates of indigenous, microorganisms and reducing agents, such as cysteine or sodium thioglycollate, or complexing agents such as the amino acid glycine, to effect the mobilization or release of the metals from the soil particles. 5 figs.

  3. Recovery of lithium and cobalt from waste lithium ion batteries of mobile phone.

    PubMed

    Jha, Manis Kumar; Kumari, Anjan; Jha, Amrita Kumari; Kumar, Vinay; Hait, Jhumki; Pandey, Banshi Dhar

    2013-09-01

    In view of the stringent environmental regulations, availability of limited natural resources and ever increasing need of alternative energy critical elements, an environmental eco-friendly leaching process is reported for the recovery of lithium and cobalt from the cathode active materials of spent lithium-ion batteries of mobile phones. The experiments were carried out to optimize the process parameters for the recovery of lithium and cobalt by varying the concentration of leachant, pulp density, reductant volume and temperature. Leaching with 2M sulfuric acid with the addition of 5% H(2)O(2) (v/v) at a pulp density of 100 g/L and 75°C resulted in the recovery of 99.1% lithium and 70.0% cobalt in 60 min. H(2)O(2) in sulfuric acid solution acts as an effective reducing agent, which enhance the percentage leaching of metals. Leaching kinetics of lithium in sulfuric acid fitted well to the chemical controlled reaction model i.e. 1-(1-X)(1/3)=k(c)t. Leaching kinetics of cobalt fitted well to the model 'ash diffusion control dense constant sizes spherical particles' i.e. 1-3(1-X)(2/3)+2(1-X)=k(c)t. Metals could subsequently be separated selectively from the leach liquor by solvent extraction process to produce their salts by crystallization process from the purified solution.

  4. Determination of fuel ethers in water by membrane extraction ion mobility spectrometry.

    PubMed

    Holopainen, Sanna; Nousiainen, Marjaana; Sillanpää, Mika

    2013-03-15

    Fuel oxygenates are environmentally detrimental compounds due to their rapid migration to groundwater. Fuel oxygenates have been reported to cause taste and odour problems in drinking water, and they also have long-term health effects. Feasible analytical methods are required to observe the presence of fuel oxygenates in drinking and natural water. The authors studied ion mobility spectrometry (IMS) to determinate isomeric fuel ether oxygenates; ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME), separated from aqueous matrices with a pervaporation membrane module. Methyl tert-butyl ether (MTBE) was also membrane extracted and detected with IMS. The authors demonstrated that fuel ethers (MTBE, ETBE, DIPE, and TAME) can be quantified at μg/L level with membrane extraction IMS. A membrane extraction module coupled to IMS is a time and cost effective analysis method because sampling can be performed in a single procedure and from different natural water matrices within a few minutes. Consequently, IMS combined with membrane extraction is suitable not only for waterworks and other online applications but also in the field monitoring the quality of drinking and natural water.

  5. Off-line coupling of multidimensional immunoaffinity chromatography and ion mobility spectrometry: A promising partnership.

    PubMed

    Armenta, Sergio; de la Guardia, Miguel; Abad-Fuentes, Antonio; Abad-Somovilla, Antonio; Esteve-Turrillas, Francesc A

    2015-12-24

    The extreme specificity of immunoaffinity chromatography (IAC) columns coupled to the high sensitivity of ion mobility spectrometry (IMS) measurements makes this combination really useful for rapid, selective, and sensitive determination of a high variety of analytes in different samples. The capabilities of the IAC-IMS coupling have been highlighted under three different scenarios: (i) multiclass residue analysis using a single IAC column, (ii) multiclass residue analysis using stacked IAC columns, and (iii) isomer analysis. In the first case, the determination of three strobilurin fungicides - azoxystrobin, picoxystrobin, and pyraclostrobin - in water and strawberry juice was considered, obtaining limits of quantification (LOQs) from 11 to 63μgL(-1). Recoveries from 96 to 106% for water, and from 67 to 104% for strawberry juice were obtained. In the second case, anilinopyrimidine compounds, including two analytes with similar drift time, were selectively retained in different IAC columns and analyzed after independent elution in commercial wine samples by IMS. LOQ values of 16, 14 and 12μgL(-1) were obtained for pyrimethanil, mepanipyrim, and cyprodinil, respectively. The obtained recoveries for wine samples spiked with 25 and 100μgL(-1) were from 82 to 123%. Additionally, the stacked IAC columns concept was applied to the separation of Z and E isomers of azoxystrobin that were selectively retained in specific IAC columns and quantified by IMS. Recoveries between 91 and 94% were obtained for both isomers in water samples. PMID:26654255

  6. Simultaneous determination of three azo dyes in food product by ion mobility spectrometry.

    PubMed

    Jiao, Jiandong; Wang, Jinfeng; Li, Mingfeng; Li, Junqing; Li, Qihong; Quan, Qinbo; Chen, Jinquan

    2016-07-01

    Color is an important property for food evaluation. Synthetic azo dyes are usually used in food product to obtain better appearance because of their stability and low cost. However, such dyes should be strictly controlled because of their potential threat to human health. A simple, rapid and sensitive method has been developed to determine orange II, allura red, and para red simultaneously by ion mobility spectrometry. The three dyes could be separated at the same time and the migration time of orange II, allura red, and para red are 12.070±0.010, 8.180±0.015, and 11.037±0.016ms, respectively. The effects of different parameters, such as pH, solvent, percentage of water, were investigated to establish the optimal condition. The detection limits were 0.1, 0.05, and 0.2μg/mL for orange II, allura red, and para red, respectively. The recoveries of the three azo dyes from jellies were all higher than 81%. The developed method is fast and accurate for the detection of the three synthetic dyes. PMID:27235999

  7. Combining Ion Mobility Spectrometry with Hydrogen-Deuterium Exchange and Top-Down MS for Peptide Ion Structure Analysis

    NASA Astrophysics Data System (ADS)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Maleki, Hossein; Arndt, James R.; Donohoe, Gregory C.; Valentine, Stephen J.

    2014-12-01

    The gas-phase conformations of electrosprayed ions of the model peptide KKDDDDIIKIIK have been examined by ion mobility spectrometry (IMS) and hydrogen deuterium exchange (HDX)-tandem mass spectrometry (MS/MS) techniques. [M+4H]4+ ions exhibit two conformers with collision cross sections of 418 Å2 and 471 Å2. [M+3H]3+ ions exhibit a predominant conformer with a collision cross section of 340 Å2 as well as an unresolved conformer (shoulder) with a collision cross section of ~367 Å2. Maximum HDX levels for the more compact [M+4H]4+ ions and the compact and partially-folded [M+3H]3+ ions are ~12.9, ~15.5, and ~14.9, respectively. Ion structures obtained from molecular dynamics simulations (MDS) suggest that this ordering of HDX level results from increased charge-site/exchange-site density for the more compact ions of lower charge. Additionally, a new model that includes two distance calculations (charge site to carbonyl group and carbonyl group to exchange site) for the computer-generated structures is shown to better correlate to the experimentally determined per-residue deuterium uptake. Future comparisons of IMS-HDX-MS data with structures obtained from MDS are discussed with respect to novel experiments that will reveal the HDX rates of individual residues.

  8. METHOD OF SEPARATING RARE EARTHS BY ION EXCHANGE

    DOEpatents

    Spedding, F.H.; Powell, J.E.

    1960-10-18

    A process is given for separating yttrium and rare earth values having atomic numbers of from 57 through 60 and 68 through 71 from an aqueous solution whose pH value can range from 1 to 9. All rare earths and yttrium are first adsorbed on a cation exchange resin, and they are then eluted with a solution of N-hydroxyethylethylenediaminetriacetic acid (HEDTA) in the order of decreasing atomic number, yttrium behaving like element 61; the effluents are collected in fractions. The HEDTA is recovered by elution with ammonia solution and the resin is regenerated with sulfuric acid. Rare earths are precipitated from the various effluents with oxalic acid, and each supernatant is passed over cation exchange resin for adsorption of HEDTA and nonprecipitated rare earths: the oxalic acid is not retained by the resin.

  9. Atmospheric Pressure Chemical Ionization Sources Used in The Detection of Explosives by Ion Mobility Spectrometry

    SciTech Connect

    Waltman, Melanie J.

    2010-05-01

    Explosives detection is a necessary and wide spread field of research. From large shipping containers to airline luggage, numerous items are tested for explosives every day. In the area of trace explosives detection, ion mobility spectrometry (IMS) is the technique employed most often because it is a quick, simple, and accurate way to test many items in a short amount of time. Detection by IMS is based on the difference in drift times of product ions through the drift region of an IMS instrument. The product ions are created when the explosive compounds, introduced to the instrument, are chemically ionized through interactions with the reactant ions. The identity of the reactant ions determines the outcomes of the ionization process. This research investigated the reactant ions created by various ionization sources and looked into ways to manipulate the chemistry occurring in the sources.

  10. Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

    DOEpatents

    Dietz, Mark L.; Horwitz, E. Philip; Bartsch, Richard A.; Barrans, Jr., Richard E.; Rausch, David

    1999-01-01

    A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution.

  11. Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

    DOEpatents

    Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

    1999-03-30

    A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.

  12. Tannic-Acid-Coated Polypropylene Membrane as a Separator for Lithium-Ion Batteries.

    PubMed

    Pan, Lei; Wang, Haibin; Wu, Chaolumen; Liao, Chenbo; Li, Lei

    2015-07-29

    To solve the wetting capability issue of commercial polypropylene (PP) separators in lithium-ion batteries (LIBs), we developed a simple dipping surface-coating process based on tannic acid (TA), a natural plant polyphenol. Fourier transform infrared and X-ray photoelectron measurements indicate that the TA is coated successfully on the PP separators. Scanning electron microscopy images show that the TA coating does not destroy the microporous structure of the separators. After being coated with TA, the PP separators become more hydrophilic, which not only enhances the liquid electrolyte retention ability but also increases the ionic conductivity. The battery performance, especially for power capability, is improved after being coated with TA. It indicates that this TA-coating method provides a promising process by which to develop an advanced polymer membrane separator for lithium-ion batteries.

  13. Temperature dependent mobility measurements of alkali earth ions in superfluid helium

    NASA Astrophysics Data System (ADS)

    Putlitz, Gisbert Zu; Baumann, I.; Foerste, M.; Jungmann, K.; Riediger, O.; Tabbert, B.; Wiebe, J.; Zühlke, C.

    1998-05-01

    Mobility measurements of impurity ions in superfluid helium are reported. Alkali earth ions were produced with a laser sputtering technique and were drawn inside the liquid by an electric field. The experiments were carried out in the temperature region from 1.27 up to 1.66 K. The temperature dependence of the mobility of Be^+-ions (measured here for the first time) differs from that of the other alkali earth ions Mg^+, Ca^+, Sr^+ and Ba^+, but behaves similar to that of He^+ (M. Foerste, H. Günther, O. Riediger, J. Wiebe, G. zu Putlitz, Z. Phys. B) 104, 317 (1997). Theories of Atkins (A. Atkins, Phys. Rev.) 116, 1339 (1959) and Cole (M.W. Cole, R.A. Bachmann Phys. Rev. B) 15, 1388 (1977) predict a different defect structure for He^+ and the alkali earth ions: the helium ion is assumed to form a snowball like structure whereas for the alkali earth ions a bubble structure is assumed. If the temperature dependence is a characteristic feature for the different structures, then it seems likely that the Be^+ ion builds a snowball like structure.

  14. Separation and investigation of structure-mobility relationships of insect oostatic peptides by capillary zone electrophoresis.

    PubMed

    Solínová, Veronika; Kasicka, Václav; Koval, Dusan; Hlavácek, Jan

    2004-07-01

    Capillary zone electrophoresis (CZE) has been applied to qualitative analysis, separation, and physicochemical characterization of synthetic insect oostatic peptides (IOPs) and their derivatives and fragments. Series of homologous IOPs were separated in three acidic background electrolytes (BGEs; pH 2.25, 2.30, 2.40) and an alkaline BGE (pH 8.1). Best separation was achieved in acid BGE composed of 100 mM H3PO4, 50 mM Tris, pH 2.25. The effective electrophoretic mobilities, mu(ep), of all IOPs in four BGEs were determined and several semiempirical models correlating effective mobility with charge-to-size ratio (mu(ep) versus q/Mr k) were tested to describe the migration behavior of IOP in CZE. None of models was found to be unambiguously applicable for the whole set of 20 IOPs differing in size (dipeptide - decapeptide) and charge (-2 to +0.77 elementary charges). However, a high coefficient of correlation, 0.9993, was found for the subset of homologous series of IOPs with decreasing number of proline residues at C-terminus, H-Tyr-Asp-Pro-Ala-Prox-OH, x = 6 - 0, for the dependence of mu(ep) on q/Mr k with k = 0.5 for IOPs as anions in alkaline BGE and with k = 2/3 for IOPs as cations in optimized acidic Tris-phosphate BGE. From these dependences the probable structure of IOPs in solution could be predicted. PMID:15274012

  15. Enhanced capacity and stability for the separation of cesium in electrically switched ion exchange

    SciTech Connect

    Tawfic, A.F.; Dickson, S.E.; Kim, Y.; Mekky, W.

    2015-03-15

    Electrically switched ion exchange (ESIX) can be used to separate ionic contaminants from industrial wastewater, including that generated by the nuclear industry. The ESIX method involves sequential application of reduction and oxidation potentials to an ion exchange film to induce the respective loading and unloading of cesium. This technology is superior to conventional methods (e.g electrodialysis reversal or reverse osmosis) as it requires very little energy for ionic separation. In previous studies, ESIX films have demonstrated relatively low ion exchange capacities and limited film stabilities over repeated potential applications. In this study, the methodology for the deposition of electro-active films (nickel hexacyanoferrate) on nickel electrodes was modified to improve the ion exchange capacity for cesium removal using ESIX. Cyclic voltammetry was used to investigate the ion exchange capacity and stability. Scanning electron microscopy (SEM) was used to characterize the modified film surfaces. Additionally, the films were examined for the separation of cesium ions. This modified film preparation technique enhanced the ion exchange capacity and improves the film stability compared to previous methods for the deposition of ESIX films. (authors)

  16. Separation of Metal Ions from Liquid Waste Streams

    SciTech Connect

    Glasgow, D. G.; Kennel, E. B.

    2004-12-01

    A unique mechanism was verified for removing uranium from continuously flowing aqueous solutions on a carbon nanofiber electrode with a bias voltage of -0.9 volts (dc versus Ag/AgC1). Uranium concentration was reduced from 100 ppm in the inlet feed to below 1 ppm in a single pass. Cell sizes of 1 cm, 2 inch and 4 inch evaluated during this program were all found to electrosorb uranium from an aqueous stream. The 4 inch cell performed well at uranium concentrations of 1000 ppm. Normally, ordinary electrolysis is not an option for removing uranyl ions because the electrodeposition potential is higher than the dissociation voltage of water. Thus, the ability to electrosorb uranium with greater than 99% effectiveness is a surprising result. In addition, the process was found to be reversible, so that the uranium can be released in a highly concentrated form. In addition to verifying the effectiveness of the system on bench top scale, a regeneration protocol was developed, consisting of passing a 0.1 M KNO{sub3}, solution at a pH of 2.0 and an applied potential of +1.0 V (dc versus Ag/AgC1) which resulted in a measured regeneration of 70% of the electrosorbed uranium. Other experiments studied the effect of pH on electrosorption and desorption, establishing a range of pH for both processes. Finally, it was found that, for an inlet solution of 100 ppm, the carbon nanofiber electrodes were able to electrosorb an amount of uranium in excess of 60% of the electrode mass.

  17. Investigation of isomeric flavanol structures in black tea thearubigins using ultraperformance liquid chromatography coupled to hybrid quadrupole/ion mobility/time of flight mass spectrometry.

    PubMed

    Yassin, Ghada H; Grun, Christian; Koek, Jean H; Assaf, Khaleel I; Kuhnert, Nikolai

    2014-11-01

    Ultra performance liquid chromatography (UPLC) when coupled to ion mobility (IMS)/orthogonal acceleration time of flight mass spectrometry is a suitable technique for analyzing complex mixtures such as the black tea thearubigins. With the aid of this advanced instrumental analysis, we were able to separate and identify different isomeric components in the complex mixture which could previously not be differentiated by a conventional high performance liquid chromatography/tandem mass spectrometry. In this study, the difference between isomeric structures theasinensins, proanthocyanidins B-type and rutin (quercetin-3O-rutinoside) were studied, and these are present abundantly in many botanical sources. The differentiation between these structures was accomplished according to their acquired mobility drift times differing from the traditional investigations in mass spectrometry, where calculation of theoretical collisional cross sections allowed assignment of the individual isomeric structures. The present work demonstrates UPLC-IMS-MS as an efficient technology for isolating and separating isobaric and isomeric structures existing in complex mixtures discriminating between them according to their characteristic fragment ions and mobility drift times. Therefore, a rational assignment of isomeric structures in many phenolic secondary metabolites based on the ion mobility data might be useful in mass spectrometry-based structure analysis in the future.

  18. Transversal modulation ion mobility spectrometry (IMS) coupled with mass spectrometry (MS): exploring the IMS-IMS-MS possibilities of the instrument.

    PubMed

    Vidal-de-Miguel, G; Macía, M; Barrios, C; Cuevas, J

    2015-02-01

    A prototype is introduced based on the transversal modulation ion mobility spectrometry (TMIMS) technique, which provides a continuous output of mobility-selected ions, greatly easing the synchronization between different analyzing stages. In the new architecture, two stages of filtration are used to drastically reduce the background produced by one stage alone. Two-stages TMIMS was coupled with two different atmospheric pressure interface mass spectrometers (MS). The new system enables IMS-IMS-MS analysis and other modes of operation: IMS prefiltration, IMS-IMS, and full transmission mode. It provides a resolving power R > 60 in IMS mode, and R > 40 in each stage of IMS-IMS mode. 2-Propanol vapors were introduced in one of the stages to enhance the mobility variations, and their effect was studied on a set of tetraalkylammonium ions. We found that concentrations as low as 1% (in partial pressure) produce mobility variations as high as 20%, which suggest that IMS-IMS separation using dried N2 (in one stage) and a dopant (in the other stage), could be a very powerful way to enhance the separation capacity of the IMS-IMS prefiltration approach.

  19. Deformation and failure characteristics of four types of lithium-ion battery separators

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaowei; Sahraei, Elham; Wang, Kai

    2016-09-01

    Mechanical properties and failure mechanisms of battery separators play a crucial role in integrity of Lithium-ion batteries during an electric vehicle crash event. In this study, four types of commonly used battery separators are characterized and their mechanical performance, strength, and failure are compared. This includes two dry-processed polyethylene (PE) and trilayer separators, a wet-processed ceramic-coated separator, and a nonwoven separator. In detail, uniaxial tensile tests were performed along machine direction (MD), transverse direction (TD) and diagonal direction (DD). Also, through-thickness compression tests and biaxial punch tests were conducted. Comprehensive mechanical tests revealed interesting deformation and failure patterns under extreme mechanical loads. Last, a finite element model of PE separator was developed in LSDYNA based on the uniaxial tensile and through-thickness compression test data. The model succeeded in predicting the response of PE separator under punch tests with different sizes of punch head.

  20. Shutdown-functionalized nonwoven separator with improved thermal and electrochemical properties for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kim, Youngkwon; Lee, Won-Yeol; Kim, Ki Jae; Yu, Ji-Sang; Kim, Young-Jun

    2016-02-01

    A shutdown-functionalized nonwoven separator (SFNS) with improved thermal and electrochemical stabilities is prepared by a simple dip coating method for use in lithium-ion battery (LiB) applications. The SFNS shows thermal stability at 200 °C, while providing shutdown functionality at approximately 140 °C, similar to commercial porous polyethylene separators. The surface-coated polymer prevents leakage current problems and in addition, shows air permeability values similar to that of bare nonwoven separators, while maintaining a thickness of about 20 μm, which is a desired attribute of effective separators for LiBs. The SFNS also shows increased electrolyte uptake and higher conductivity, compared to a bare polyethylene separator. Therefore, a cell with the SFNS exhibits higher discharge capacity and better cycle property than that with a porous polyethylene separator. These results suggest that SFNS is an effective separator for high-performance LiBs.

  1. Development and characterization of silica tube-coated separator for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Chen, Lixiao; Shi, Chuan; Yang, Pingting; Zhao, Jinbao

    2015-06-01

    In an endeavor to improve the thermal stability of lithium-ion batteries (LIBs), a new kind of ceramic coated separator has been developed based on introducing one-dimensional silica tubes (ST) to one side of a commercial polyethylene (PE) porous separator. The ST interpenetrating network diminishes the thermal-induced dimensional change of the commercial separator without compromising the cell performance. In particular, compared to spherical silica particle (SP) coated separator, the ST coated separator exhibits significantly enhanced thermal stability at elevated temperature. Furthermore the ST coated separator shows better mechanical performance as well as the improved electrolyte absorption and retention behavior, which provides a promising solution to replace conventional polymer separator for high-performance LIBs.

  2. Enhanced electrochemical performance of nanoparticle coated polyethylene separator surface for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Sivaprakash, Prabhavathy; Sen, P. K.; Sivaprakash, S.

    2014-12-01

    The separator (membrane) in a lithium ion rechargeable battery plays an indispensable role by preventing material and electrical contact of positive and negative electrodes, allowing swift ionic flow within the cell. Herein, we report an interesting approach to improve performance of readily available polyolefin separator by coating it with synthesized silica nanoparticles/polyvinylidene fluoride optimal blend. This coated composite separator was investigated for surface morphology, wettability, electrolyte uptake, thermal stability and performance studies. Coin cells fabricated using surface coated separator show good C-rate capability and stable cycle performance with capacity retention of 99% even after 50 cycles.

  3. In-depth correlation of separator pore structure and electrochemical performance in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Lee, Yunju; Park, Joonam; Jeon, Hyunkyu; Yeon, Daeyong; Kim, Byung-Hyun; Cho, Kuk Young; Ryou, Myung-Hyun; Lee, Yong Min

    2016-09-01

    To establish an accurate correlation between a separator's pore structure and the electrochemical performance of a lithium-ion battery (LIB), we fabricate well defined polyethylene (PE) separators on the same production line while maintaining most processing variables, except for composition. Four PE separators having different thicknesses and porosities (16 μm/37%, 16 μm/40%, 16 μm/47%, 22 μm/47%, respectively) are physically and electrochemically evaluated in detail. Although thickness and porosity remain good parameters by which to represent the separators' characteristics, both the normalized Gurley number and ionic conductance are found to have much stronger relationships with the rate capability.

  4. Effects of separator breakdown on abuse response of 18650 Li-ion cells

    NASA Astrophysics Data System (ADS)

    Roth, E. P.; Doughty, D. H.; Pile, D. L.

    The thermal abuse tolerance of Li-ion cells depends not only on the stability of the active materials in the anode and cathode but also on the stability of the separator which prevents direct interaction between these electrodes. Separator response has been measured as a function of temperature and high voltage both for isolated materials and in full 18650 cells. Separators with different compositions and properties were measured to determine the effect of separator melt integrity on cell response under abusive conditions. These studies were performed as part of the U.S. Department of Energy (DOE) Advanced Technology Development (ATD) Program.

  5. Analyzing slowly exchanging protein conformations by ion mobility mass spectrometry: study of the dynamic equilibrium of prolyl oligopeptidase.

    PubMed

    López, Abraham; Vilaseca, Marta; Madurga, Sergio; Varese, Monica; Tarragó, Teresa; Giralt, Ernest

    2016-07-01

    Ion mobility mass spectrometry (IMMS) is a biophysical technique that allows the separation of isobaric species on the basis of their size and shape. The high separation capacity, sensitivity and relatively fast time scale measurements confer IMMS great potential for the study of proteins in slow (µs-ms) conformational equilibrium in solution. However, the use of this technique for examining dynamic proteins is still not generalized. One of the major limitations is the instability of protein ions in the gas phase, which raises the question as to what extent the structures detected reflect those in solution. Here, we addressed this issue by analyzing the conformational landscape of prolyl oligopeptidase (POP) - a model of a large dynamic enzyme in the µs-ms range - by native IMMS and compared the results obtained in the gas phase with those obtained in solution. In order to interpret the experimental results, we used theoretical simulations. In addition, the stability of POP gaseous ions was explored by charge reduction and collision-induced unfolding experiments. Our experiments disclosed two species of POP in the gas phase, which correlated well with the open and closed conformations in equilibrium in solution; moreover, a gas-phase collapsed form of POP was also detected. Therefore, our findings not only support the potential of IMMS for the study of multiple co-existing conformations of large proteins in slow dynamic equilibrium in solution but also stress the need for careful data analysis to avoid artifacts. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Analysis of Supramolecular Complexes of 3-Methylxanthine with Field Asymmetric Waveform Ion Mobility Spectrometry Combined with Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Arthur, Kayleigh L.; Eiceman, Gary A.; Reynolds, James C.; Creaser, Colin S.

    2016-05-01

    Miniaturised field asymmetric waveform ion mobility spectrometry (FAIMS), combined with mass spectrometry (MS), has been applied to the study of self-assembling, noncovalent supramolecular complexes of 3-methylxanthine (3-MX) in the gas phase. 3-MX forms stable tetrameric complexes around an alkali metal (Na+, K+) or ammonium cation, to generate a diverse array of complexes with single and multiple charge states. Complexes of (3-MX)n observed include: singly charged complexes where n = 1-8 and 12 and doubly charged complexes where n = 12-24. The most intense ions are those associated with multiples of tetrameric units, where n = 4, 8, 12, 16, 20, 24. The effect of dispersion field on the ion intensities of the self-assembled complexes indicates some fragmentation of higher order complexes within the FAIMS electrodes (in-FAIMS dissociation), as well as in-source collision induced dissociation within the mass spectrometer. FAIMS-MS enables charge state separation of supramolecular complexes of 3-MX and is shown to be capable of separating species with overlapping mass-to-charge ratios. FAIMS selected transmission also results in an improvement in signal-to-noise ratio for low intensity complexes and enables the visualization of species undetectable without FAIMS.

  7. Estimating collision cross sections of negatively charged N-glycans using traveling wave ion mobility-mass spectrometry.

    PubMed

    Hofmann, Johanna; Struwe, Weston B; Scarff, Charlotte A; Scrivens, James H; Harvey, David J; Pagel, Kevin

    2014-11-01

    Glycosylation is one of the most common post-translational modifications occurring in proteins. A detailed structural characterization of the involved carbohydrates, however, is still one of the greatest challenges in modern glycoproteomics, since multiple regio- and stereoisomers with an identical monosaccharide composition may exist. Recently, ion mobility-mass spectrometry (IM-MS), a technique in which ions are separated according to their mass, charge, and shape, has evolved as a promising technique for the separation and structural analysis of complex carbohydrates. This growing interest is based on the fact that the measured drift times can be converted into collision cross sections (CCSs), which can be compared, implemented into databases, and used as additional search criteria for structural identification. However, most of the currently used commercial IM-MS instruments utilize a nonuniform traveling wave field to propel the ions through the IM cell. As a result, CCS measurements cannot be performed directly and require calibration. Here, we present a calibration data set consisting of over 500 reference CCSs for negatively charged N-glycans and their fragments. Moreover, we show that dextran, already widely used as a calibrant in high performance liquid chromatography, is also a suitable calibrant for CCS estimations. Our data also indicate that a considerably increased error has to be taken into account when reference CCSs acquired in a different drift gas are used for calibration. PMID:25268221

  8. Rapid separation of desloratadine and related compounds in solid pharmaceutical formulation using gradient ion-pair chromatography.

    PubMed

    Zheng, Jinjian; Rustum, Abu M

    2010-01-01

    We reported the development of an ion-pair chromatographic method to separate desloratadine and all known related compounds in Clarinex Tablets, which use desloratadine as active pharmaceutical ingredient (API). For the first time, baseline separation for desloratadine and all known related compounds was achieved by utilizing a YMC-Pack Pro C(18) column (150 mm x 4.6 mm I.D., 3 microm particle size, 120A pore size) and a gradient elution method. The mobile phase A contains 3 mM sodium dodecylsulfate (SDS), 15 mM sodium citrate buffer at pH 6.2, and 40 mM sodium sulfate, while the mobile phase B is acetonitrile. Chromsword, an artificial intelligence method development tool, was used to optimize several key chromatographic parameters simultaneously including buffer pH/solvent strength, and temperature/gradient profile. The resolution of desloratadine and desloratadine 3,4-dehydropiperidine derivative, one of the critical pairs was improved by adding 40 mM sodium sulfate. Ultraviolet detection at 267 nm was used to achieve the detection for desloratadine and all compounds. This method has been successfully validated according to ICH guidelines in terms of linearity, accuracy, quantitation limit/detection limit, precision, specificity and robustness. It could be used as a stability indicating method for desloratadine drug substances or drug products that use desloratadine as active pharmaceutical ingredient.

  9. Preparation and characterization of a Lithium-ion battery separator from cellulose nanofibers.

    PubMed

    Zhang, Hongfeng; Wang, Xiwen; Liang, Yun

    2015-10-01

    Optimizing the desired properties for stretch monolayer separators used in Lithium-ion batteries has been a challenge. In the present study a cellulose nanofiber/PET nonwoven composite separator is successfully fabricated, using a wet-laid nonwoven (papermaking) process, which can attain optimal properties in wettability, mechanical strength, thermal resistance, and electrochemical performance simultaneously. The PET nonwoven material, which is fabricated from ultrafine PET fibers by a wet-laid process, is a mechanical support layer. The porous structure of the composite separator was created by cellulose nanofibers coating the PET in a papermaking process. Cellulose nanofibers (CNFs), which are an eco-friendly sustainable resource, have been drawing considerable attention due to their astounding properties, such as: incredible specific surface area, thermal and chemical stability, high mechanical strength and hydrophilicity. The results show that the CNF separator exhibits higher porosity (70%) than a PP (polypropylene) separator (40%). The CNF separator can also be wetted by electrolyte in a few seconds while a PP separator cannot be entirely wetted after 1 min. The CNF separator has an electrolyte uptake of 250%, while a PP separator has only 65%. Another notable finding is that the CNF separator has almost no shrinkage when exposed to 180 °C for 1 h, whereas a PP separator shrinks by more than 50%. Differential Scanning Calorimetry (DSC) shows that the CNF separator has a higher melting point than a PP separator. These findings all indicate that the CNF 29 separator will be more favorable than stretch film for use in Lithium-ion batteries. PMID:27441220

  10. High Mobility SiGe/Si Transistor Structures on Sapphire Substrates Using Ion Implantation

    NASA Technical Reports Server (NTRS)

    Alterovitz, S. A.; Mueller, C. H.; Croke, E. T.

    2003-01-01

    High mobility n-type SiGe/Si transistor structures have been fabricated on sapphire substrates by ion implanting phosphorus ions into strained 100 Angstrom thick silicon channels for the first time. The strained Si channels were sandwiched between Si(sub 0.7)Ge(sub 0.3) layers, which, in turn, were deposited on Si(sub 0.7)Ge(sub 0.3) virtual substrates and graded SiGe buffer layers. After the molecular beam epitaxy (MBE) film growth process was completed, ion thick silicon channels implantation and post-annealing were used to introduce donors. The phosphorous ions were preferentially located in the Si channel at a peak concentration of approximately 1x10(exp 18)/cu cm. Room temperature electron mobilities exceeding 750 sq cm/V-sec at carrier densities of 1x10(exp 12)/sq cm were measured. Electron concentration appears to be the key factor that determines mobility, with the highest mobility observed for electron densities in the 1 - 2x10(exp 12)/sq cm range.

  11. How alkali metal ion binding alters the conformation preferences of gramicidin A: a molecular dynamics and ion mobility study.

    PubMed

    Chen, Liuxi; Gao, Yi Qin; Russell, David H

    2012-01-12

    Here, we present a systematic study combing electrospray ionization-ion mobility experiments and an enhanced sampling molecular dynamics, specifically integrated tempering sampling molecular dynamics simulations (ITS-MDS), to explore the conformations of alkali metal ion (Na, K, and Cs) adducts of gramicidin A (GA) in vacuo. Folding simulation is performed to obtain inherent conformational preferences of neutral GA to provide insights about how the binding of metal ions influences the intrinsic conformations of GA. The comparison between conformations of neutral GA and alkali metal ion adducts reveals a high degree of structural similarity, especially between neutral GA and [GA + Na](+); however, the structural similarities decrease as ionic radius of the metal increases. Collision cross section (CCS) profiles for [GA + Na](+) and [GA + Cs](+) ions obtained from by ITS-MDS compare favorably with the experimental CCS, but there are significant differences from CCS profiles for [GA + K](+) ions. Such discrepancies between the calculated and measured CCS profiles for [GA + K](+) are discussed in terms of limitations in the simulation force field as well as possible size-dependent coordination of the [GA + K](+) ion complex.

  12. Silver-Ion Solid Phase Extraction Separation of Classical, Aromatic, Oxidized, and Heteroatomic Naphthenic Acids from Oil Sands Process-Affected Water.

    PubMed

    Huang, Rongfu; Chen, Yuan; Gamal El-Din, Mohamed

    2016-06-21

    The separation of classical, aromatic, oxidized, and heteroatomic (sulfur-containing) naphthenic acid (NA) species from unprocessed and ozone-treated oil sands process-affected water (OSPW) was performed using silver-ion (Ag-ion) solid phase extraction (SPE) without the requirement of pre-methylation for NAs. OSPW samples before SPE and SPE fractions were characterized using ultra performance liquid chromatography ion mobility time-of-flight mass spectrometry (UPLC-IM-TOFMS) to corroborate the separation of distinct NA species. The mass spectrum identification applied a mass tolerance of ±1.5 mDa due to the mass errors of NAs were measured within this range, allowing the identification of O2S-NAs from O2-NAs. Moreover, separated NA species facilitated the tandem mass spectrometry (MS/MS) characterization of NA compounds due to the removal of matrix and a simplified composition. MS/MS results showed that classical, aromatic, oxidized, and sulfur-containing NA compounds were eluted into individual SPE fractions. Overall results indicated that the separation of NA species using Ag-ion SPE is a valuable method for extracting individual NA species that are of great interest for environmental toxicology and wastewater treatment research, to conduct species-specific studies. Furthermore, the separated NA species on the milligram level could be widely used as the standard materials for environmental monitoring of NAs from various contamination sites. PMID:27183033

  13. Ion-exchange chromatography separation applied to mineral recycle in closed systems

    NASA Technical Reports Server (NTRS)

    Ballou, E.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

    1981-01-01

    As part of the controlled ecological life support system (CELSS) program, a study is being made of mineral separation on ion-exchange columns. The purpose of the mineral separation step is to allow minerals to be recycled from the oxidized waste products of plants, man, and animals for hydroponic food production. In the CELSS application, relatively large quantities of minerals in a broad concentration range must be recovered by the desired system, rather than the trace quantities and very low concentrations treated in analytical applications of ion-exchange chromatography. Experiments have been carried out to assess the parameters pertinent to the scale-up of ion-exchange chromatography and to determine feasibility. Preliminary conclusions are that the column scale-up is in a reasonable size range for the CELSS application. The recycling of a suitable eluent, however, remains a major challenge to the suitability of using ion exchange chromatography in closed systems.

  14. Identification of novel isomeric pectic oligosaccharides using hydrophilic interaction chromatography coupled to traveling-wave ion mobility mass spectrometry.

    PubMed

    Leijdekkers, Antonius G M; Huang, Jie-Hong; Bakx, Edwin J; Gruppen, Harry; Schols, Henk A

    2015-03-01

    Separation and characterization of complex mixtures of pectic oligosaccharides still remains challenging and often requires the use of multiple analytical techniques, especially when isomeric structures are present. In this work, it is demonstrated that the coupling of hydrophilic interaction chromatography (HILIC) to traveling-wave ion mobility mass spectrometry (TWIMMS) enabled the simultaneous separation and characterization of complex mixtures of various isomeric pectic oligosaccharides. Labeling of oligosaccharides with 3-aminoquinoline (3-AQ) improved MS-ionization efficiency of the oligosaccharides and reduced the complexity of the product ion mass spectra, without losing resolution of the HILIC separation. In addition, labeling enabled quantification of oligosaccharides on molar basis using in-line fluorescence detection. Isomeric structures were distinguished using TWIMMS. The 3-AQ-HILIC-TWIMMS method was used to characterize a series of isomeric sugar beet rhamnogalacturonan I derived oligosaccharides carrying a glucuronic acid substituent. Thereby, some novel structural features were identified for the first time: glucuronic acid was attached to O-3 or to O-2 of galacturonic acid residues and a single galacturonic acid residue within an oligomer could contain both an acetyl group and a glucuronic acid substituent.

  15. Method and apparatus for ion mobility spectrometry with alignment of dipole direction (IMS-ADD)

    DOEpatents

    Shvartsburg, Alexandre A.; Tang, Keqi; Smith, Richard D.

    2007-01-30

    Techniques and instrumentation are described for analyses of substances, including complex samples/mixtures that require separation prior to characterization of individual components. A method is disclosed for separation of ion mixtures and identification of ions, including protein and other macromolecular ions and their different structural isomers. Analyte ions are not free to rotate during the separation, but are substantially oriented with respect to the drift direction. Alignment is achieved by applying, at a particular angle to the drift field, a much stronger alternating electric field that "locks" the ion dipoles with moments exceeding a certain value. That value depends on the buffer gas composition, pressure, and temperature, but may be as low as .about.3 Debye under certain conditions. The presently disclosed method measures the direction-specific cross-sections that provide the structural information complementing that obtained from known methods, and, when coupled to those methods, increases the total peak capacity and specificity of gas-phase separations. Simultaneous 2-D separations by direction-specific cross sections along and orthogonally to the ion dipole direction are also possible.

  16. Cryogenic molecular separation system for radioactive {sup 11}C ion acceleration

    SciTech Connect

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.

    2015-12-15

    A {sup 11}C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. In the ISOL system, {sup 11}CH{sub 4} molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive {sup 12}CH{sub 4} gases, which can simulate the chemical characteristics of {sup 11}CH{sub 4} gases. We investigated the separation of CH{sub 4} molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH{sub 4}. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  17. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins

    NASA Astrophysics Data System (ADS)

    Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J.

    2015-04-01

    Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.

  18. Characterization of tetramethylsilane for liquid-filled ionization dosimeters: Ion mobilities, free-ion yield and general recombination

    NASA Astrophysics Data System (ADS)

    Gago-Arias, A.; Argüeso, P.; Aguiar, P.; González-Castaño, D. M.; Gómez, F.; Pardo-Montero, J.

    2015-06-01

    Liquid-filled ionization chambers (LICs) are interesting detectors for the dosimetry of radiotherapy beams due to their water-equivalent response and high spatial resolution. Isooctane is the liquid most often used as an active medium, but other hydrocarbons, particularly tetramethylsilane (TMS), can be suitable for dosimetry. In this work we present a characterization of TMS (Merck, NMR calibration grade, purity > 99.7 %) for its use in LICs. The characterization consisted of measuring ion mobilities, using low dose 6 MV photon pulses from a medical linac, and free-ion yield, using a continuous cobalt-60 beam (the reference beam quality used in radiotherapy dosimetry). Those values were then used to model general recombination in a TMS-filled LIC. Measured ion mobilities, (2.6±0.3)×10-8 and (3.6±0.4)×10-8 m2 V-1 s-1, are similar to mobilities in isooctane, and two- to three-fold lower than some values reported for TMS. Such discrepancy can probably be attributed to the presence of different impurities. On the other hand, free-ion yield values obtained are approximately two-fold higher than for isooctane, in agreement with published data. Such high free-ion yield values result in a higher signal-to-noise ratio and may allow even better spatial resolution to be obtained with TMS-filled LICs. However, it comes at the cost of higher recombination effects that can compromise the operation of the chamber. Such high recombination and the low boiling point of TMS (≃ 28 ° C) make isooctane-filled LICs preferable to TMS-filled LICS for radiotherapy applications.

  19. Ion chromatographic separation of inorganic ions using a combination of hydrophilic interaction chromatographic column and cation-exchange resin column.

    PubMed

    Arai, Kaori; Mori, Masanobu; Hironaga, Takahiro; Itabashi, Hideyuki; Tanaka, Kazuhiko

    2012-04-01

    A combination of hydrophilic interaction chromatographic (HILIC) column and a weakly acidic cation-exchange resin (WCX) column was used for simultaneous separation of inorganic anions and cations by ion chromatography (IC). Firstly, the capability of HILIC column for the separation of analyte ions was evaluated under acidic eluent conditions. The columns used were SeQuant ZIC-HILIC (ZIC-HILIC) with a sulfobetaine-zwitterion stationary phase (ZIC-HILIC) and Acclaim HILIC-10 with a diol stationary phase (HILIC-10). When using tartaric acid as the eluent, the HILIC columns indicated strong retentions for anions, based on ion-pair interaction. Especially, HILIC-10 could strongly retain anions compared with ZIC-HILIC. The selectivity for analyte anions of HILIC-10 with 5 mmol/L tartaric acid eluent was in the order of I(-) > NO3(-) > Br(-) > Cl(-) > H2PO4(-). However, since HILIC-10 could not separate analyte cations, a WCX column (TSKgel Super IC-A/C) was connected after the HILIC column in series. The combination column system of HILIC and WCX columns could successfully separate ten ions (Na+, NH4+, K+, Mg2+, Ca2+, H2PO4(-), Cl(-), Br(-), NO3(-) and I(-)) with elution of 4 mmol/L tartaric acid plus 8 mmol/L 18-crown-6. The relative standard deviations (RSDs) of analyte ions by the system were in the ranges of 0.02% - 0.05% in retention times and 0.18% - 5.3% in peak areas through three-time successive injections. The limits of detection at signal-to-noise ratio of 3 were 0.24 - 0.30 micromol/L for the cations and 0.31 - 1.2 micromol/L for the anions. This system was applied for the simultaneous determination of the cations and the anions in a vegetable juice sample with satisfactory results.

  20. Effective Ion Mobility Calculations for Macromolecules by Scattering off Electron Clouds

    SciTech Connect

    Alexeev, Yuri; Fedorov, Dmitri; Shvartsburg, Alexandre A.

    2014-08-19

    Broad commercialization and increasing resolving power of ion mobility spectrometry/mass spectrometry (IMS/MS) platforms has engendered an explosion of IMS applications to structural characterization of gas-phase biomolecules. That has renewed interest in more accurate and rapid ion mobility calculations needed to elicit ion geometries from the measurements. An approach based on scattering off electron density isosurfaces (SEDI) that mirrors the physics of molecular collisions was proven superior to the common methods involving atomic coordinates a decade ago, but has remained impractical for large ions because of extreme computational demands. Here, we accelerate SEDI by up to ~500 times using the fragment molecular orbital (FMO) approach for surface generation and the multiplexed scattering algorithm in conjunction with the new grid extrapolation procedure for cross section evaluations. Parallelization of the code on a supercomputer has produced major further speed gains, allowing SEDI calculations for proteins (defined by over a million surface points) with the precision of <0.1% in one minute. Initial tests reveal the anticipated dependences of mobility on the ion charge state and lower cross sections in view of reduced surface roughness. Present developments are expected to lead to broad application of SEDI in IMS studies of macromolecules, enabling more accurate and reliable structural assignments.

  1. Effective ion mobility calculations for macromolecules by scattering on electron clouds.

    PubMed

    Alexeev, Yuri; Fedorov, Dmitri G; Shvartsburg, Alexandre A

    2014-08-28

    Broad commercialization and increasing resolving power of ion mobility spectrometry/mass spectrometry (IMS/MS) platforms have engendered an explosion of IMS applications to structural characterization of gas-phase biomolecules. That has renewed interest in more accurate and rapid ion mobility calculations that are needed to elicit ion geometries from the measurements. An approach based on scattering on electron density isosurfaces (SEDI) that mirrors the physics of molecular collisions was proven superior to the common methods involving atomic coordinates a decade ago but has remained impractical for large ions because of extreme computational demands. Here, we accelerate SEDI by up to ∼500 times using the fragment molecular orbital approach for surface generation and the multiplexed scattering algorithm in conjunction with the new grid extrapolation procedure for cross section evaluations. Parallelization of the code on a supercomputer has produced major further speed gains, allowing SEDI calculations for proteins (defined by over a million surface points) with a precision of <0.1% in 1 min. Initial tests reveal the anticipated dependence of mobility on the ion charge state and lower cross sections in view of reduced surface roughness. Present developments are expected to lead to broad application of SEDI in IMS studies of macromolecules, enabling more accurate and reliable structural assignments.

  2. Desorption electrospray ionization (DESI) with atmospheric pressure ion mobility spectrometry for drug detection.

    PubMed

    Roscioli, Kristyn M; Tufariello, Jessica A; Zhang, Xing; Li, Shelly X; Goetz, Gilles H; Cheng, Guilong; Siems, William F; Hill, Herbert H

    2014-04-01

    Desorption electrospray ionization (DESI) was coupled to an ambient pressure drift tube ion mobility time-of-flight mass spectrometer (IM-TOFMS) for the direct analysis of active ingredients in pharmaceutical samples. The DESI source was also coupled with a standalone IMS demonstrating potential of portable and inexpensive drug-quality testing platforms. The DESI-IMS required no sample pretreatment as ions were generated directly from tablets and cream formulations. The analysis of a range of over-the-counter and prescription tablet formations was demonstrated for amphetamine (methylphenidate), antidepressant (venlafaxine), barbiturate (Barbituric acid), depressant (alprazolam), narcotic (3-methylmorphine) and sympatholytic (propranolol) drugs. Active ingredients from soft and liquid formulations, such as Icy Hot cream (methyl salicylate) and Nyquil cold medicine (acetaminophen, dextromethorphan, doxylamine) were also detected. Increased sensitivity for selective drug responses was demonstrated through the formation of sodiated adduct ions by introducing small quantities of NaCl into the DESI solvent. Of the drugs and pharmaceuticals tested in this study, 68% (22 total samples) provided a clear ion mobility response at characteristic mobilities either as (M + H)(+), (M - H)(-), or (M + Na)(+) ions.

  3. Battery Separator Characterization and Evaluation Procedures for NASA's Advanced Lithium-Ion Batteries

    NASA Technical Reports Server (NTRS)

    Baldwin, Richard S.; Bennet, William R.; Wong, Eunice K.; Lewton, MaryBeth R.; Harris, Megan K.

    2010-01-01

    To address the future performance and safety requirements for the electrical energy storage technologies that will enhance and enable future NASA manned aerospace missions, advanced rechargeable, lithium-ion battery technology development is being pursued within the scope of the NASA Exploration Technology Development Program s (ETDP's) Energy Storage Project. A critical cell-level component of a lithium-ion battery which significantly impacts both overall electrochemical performance and safety is the porous separator that is sandwiched between the two active cell electrodes. To support the selection of the optimal cell separator material(s) for the advanced battery technology and chemistries under development, laboratory characterization and screening procedures were established to assess and compare separator material-level attributes and associated separator performance characteristics.

  4. Enhancement of ion mobility in aluminosilicate-polyphosphazene nanocomposites

    SciTech Connect

    Hutchison, J.C.; Bissessur, R.; Shriver, D.F.

    1997-09-01

    Nanocomposites of poly(bis-(2(2-methoxyethoxy)ethoxy)phosphazene) (MEEP) or cryptand[2.2.2] with the aluminosilicate Na-montmorillonite (NaMont) were studied to develop new solid electrolytes with high conductivity and a unity cation transport number. An aluminosilicate was chosen because the low basicity of the Si-O-Al framework should minimize ion pairing. To further reduce ion pairing, solvating molecules or polymers such as cryptand[2.2.2] or MEEP were introduced into the aluminosilicate. When compared to pristine Na-montmorillonite, impedance spectroscopy indicates an increase in conductivity of up to 100 for MEEP{center_dot}NaMont intercalates, and of 50 for cryptand[2.2.2]{center_dot}NaMont intercalates. The MEEP{center_dot}NaMont intercalate exhibits high ionic conductivity anisotropy with respect to the montmorillonite layers ({sigma}{sub para.}/{sigma}{sub perp.} = 100), which is consistent with increased tortuosity of the cation diffusion path perpendicular to the structure layers. The temperature dependence of the conductivity suggests that cation transport is coupled to segmental motion of the intercalated polymer, as observed previously for simple polymer-salt complexes. Nanocomposites of solvating polymers or molecules with aluminosilicates provide a promising new direction in solid-state electrolytes.

  5. Ion imprinted polymeric nanoparticles for selective separation and sensitive determination of zinc ions in different matrices.

    PubMed

    Shamsipur, Mojtaba; Rajabi, Hamid Reza; Pourmortazavi, Seied Mahdi; Roushani, Mahmoud

    2014-01-01

    Preparation of Zn(2+) ion-imprinted polymer (Zn-IIP) nanoparticles is presented in this report. The Zn-IIP nanoparticles are prepared by dissolving stoichiometric amounts of zinc nitrate and selected chelating ligand, 3,5,7,20,40-pentahydroxyflavone, in 15 mL ethanol-acetonitrile (2:1; v/v) mixture as a porogen solvent in the presence of ethylene glycol-dimethacrylate (EGDMA) as cross-linking, methacrylic acid (MAA) as functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as initiator. After polymerization, Cavities in the polymer particles corresponding to the Zn(2+) ions were created by leaching the polymer in HCl aqueous solution. The synthesized IIPs were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermal analysis techniques. Also, the pH range for rebinding of Zn(2+) ion on the IIP and equilibrium binding time were optimized, using flame atomic absorption spectrometry. In selectivity study, it was found that imprinting results increased affinity of the material toward Zn(2+) ion over other competitor metal ions with the same charge and close ionic radius. The prepared IIPs were repeatedly used and regenerated for six times without any significant decrease in polymer binding affinities. Finally, the prepared sorbent was successfully applied to the selective recognition and determination of zinc ion in different real samples.

  6. Collision Cross Sections for 20 Protonated Amino Acids: Fourier Transform Ion Cyclotron Resonance and Ion Mobility Results

    NASA Astrophysics Data System (ADS)

    Anupriya; Jones, Chad A.; Dearden, David V.

    2016-08-01

    We report relative dephasing cross sections for the 20 biogenic protonated amino acids measured using the cross sectional areas by Fourier transform ion cyclotron resonance (CRAFTI) technique at 1.9 keV in the laboratory reference frame, as well as momentum transfer cross sections for the same ions computed from Boltzmann-weighted structures determined using molecular mechanics. Cross sections generally increase with increasing molecular weight. Cross sections for aliphatic and aromatic protonated amino acids are larger than the average trend, suggesting these side chains do not fold efficiently. Sulfur-containing protonated amino acids have smaller than average cross sections, reflecting the mass of the S atom. Protonated amino acids that can internally hydrogen-bond have smaller than average cross sections, reflecting more extensive folding. The CRAFTI measurements correlate well with results from drift ion mobility (IMS) and traveling wave ion mobility (TWIMS) spectrometric measurements; CRAFTI results correlate with IMS values approximately as well as IMS and TWIMS values from independent measurements correlate with each other. Both CRAFTI and IMS results correlate well with the computed momentum transfer cross sections, suggesting both techniques provide accurate molecular structural information. Absolute values obtained using the various methods differ significantly; in the case of CRAFTI, this may be due to errors in measurements of collision gas pressure, measurement of excitation voltage, and/or dependence of cross sections on kinetic energy.

  7. Collision Cross Sections for 20 Protonated Amino Acids: Fourier Transform Ion Cyclotron Resonance and Ion Mobility Results.

    PubMed

    Anupriya; Jones, Chad A; Dearden, David V

    2016-08-01

    We report relative dephasing cross sections for the 20 biogenic protonated amino acids measured using the cross sectional areas by Fourier transform ion cyclotron resonance (CRAFTI) technique at 1.9 keV in the laboratory reference frame, as well as momentum transfer cross sections for the same ions computed from Boltzmann-weighted structures determined using molecular mechanics. Cross sections generally increase with increasing molecular weight. Cross sections for aliphatic and aromatic protonated amino acids are larger than the average trend, suggesting these side chains do not fold efficiently. Sulfur-containing protonated amino acids have smaller than average cross sections, reflecting the mass of the S atom. Protonated amino acids that can internally hydrogen-bond have smaller than average cross sections, reflecting more extensive folding. The CRAFTI measurements correlate well with results from drift ion mobility (IMS) and traveling wave ion mobility (TWIMS) spectrometric measurements; CRAFTI results correlate with IMS values approximately as well as IMS and TWIMS values from independent measurements correlate with each other. Both CRAFTI and IMS results correlate well with the computed momentum transfer cross sections, suggesting both techniques provide accurate molecular structural information. Absolute values obtained using the various methods differ significantly; in the case of CRAFTI, this may be due to errors in measurements of collision gas pressure, measurement of excitation voltage, and/or dependence of cross sections on kinetic energy. Graphical Abstract ᅟ. PMID:27220844

  8. Gas-Phase Chemical Separation of Phosphatidylcholine and Phosphatidylethanolamine Cations via Charge Inversion Ion/Ion Chemistry.

    PubMed

    Rojas-Betancourt, Stella; Stutzman, John R; Londry, Frank A; Blanksby, Stephen J; McLuckey, Scott A

    2015-11-17

    The [M + H](+) cations formed upon electrospray ionization of the glycerophospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) show distinct reactivities upon gas-phase reactions with doubly deprotonated 1,4-phenylenedipropionic acid (PDPA). PC cations undergo charge inversion via adduct formation with subsequent methyl cation and proton transfer to the acid to yield [PC - CH3](-) anions. These demethylated PC anions fragment upon ion trap collision-induced dissociation (CID) to yield products that reveal fatty acid chain lengths and degrees of unsaturation. PE cations, on the other hand, undergo charge inversion via double proton transfer to the two carboxylate moieties in doubly deprotonated PDPA to yield [PE - H](-) anions. These anions also fragment upon ion trap CID to yield product ions indicative of chain lengths and degrees of unsaturation in the fatty acyl moieties. Advantage is taken of this distinct reactivity to separate isomeric and isobaric PC and PE cations present in mass spectra of lipid mixtures. A cation precursor ion population containing a mixture of PE and PC cations is mass-selected and subjected to ion/ion charge inversion reactions that result in separation of PC and PE anions into different mass-to-charge ratios. Mass selection and subsequent ion trap CID of the lipid anions allows for the characterization of the isomeric lipids within each subclass. The charge inversion approach described here is demonstrated to provide increased signal-to-noise ratios for detection of PCs and PEs relative to the standard negative ionization approach as well as improved mixture analysis performance. PMID:26477819

  9. Mathematical modeling and remote monitoring of ion-exchange separation of transplutonium elements

    SciTech Connect

    Tselishchev, I.V.; Elesin, A.A.

    1988-07-01

    A mathematical model and calculational algorithms for the elution curves for ion-exchange separation of transplutonium elements (TPE) and the limits of optimal fractionation of the substances being separated, based on indicators of the process (yield, purification), are presented. The calculational programs are part of the programming provision of a small informational-calculational system based on the microcomputer Elektronika DZ-28, intended for remote monitoring of TPE separation. The elaborated programs can be implemented in the preliminary choice of necessary conditions of the TPE separation process, and also during and after the separation process for comparison of calculated results with the results of continuous, on-line remote monitoring and with the results of laboratory sample analysis. The possible application of the programs has been checked in the instance of the separation of curium and americium, and einsteinium and californium, the results of which are in satisfactory agreement with the results of remote and laboratory-analytical monitoring.

  10. Comprehensive analysis of fatty alcohol ethoxylates by ultra high pressure hydrophilic interaction chromatography coupled with ion mobility spectrometry mass spectrometry using a custom-designed sub-2 μm column.

    PubMed

    Ma, Qiang; Ma, Wei; Chen, Xi; Wang, Ziming; Bai, Hua; Zhang, Lanwei; Li, Wentao; Wang, Chao; Li, Xinshi

    2015-06-01

    Comprehensive analysis of fatty alcohol ethoxylates has been conducted by coupling ultra high pressure hydrophilic interaction chromatography and ion mobility spectrometry mass spectrometry. A custom-designed sub-2 μm column was used for the chromatographic separation of fatty alcohol ethoxylates by hydrophilic interaction chromatography. Ion mobility spectrometry provided a post-ionization resolution during a very short period of 6.4 ms. Distinguishable families of singly, doubly, and triply charged fatty alcohol ethoxylates were clearly observed. By virtue of the combination of hydrophilic interaction chromatography and ion mobility spectrometry, comprehensive resolution based on both hydrophobicity difference and mobility disparity has been achieved for fatty alcohol ethoxylates. The orthogonality of the developed separation and analysis system was evaluated with the correlation coefficient and peak spreading angle of 0.0224 and 88.72°, respectively. The actual peak capacity obtained was individually 40 and 193 times than those when hydrophilic interaction chromatography and ion mobility spectrometry were used alone. The collision cross-sections of fatty alcohol ethoxylates were calculated by calibrating the traveling wave ion mobility device with polyalanine.

  11. ION-EXCHANGE METHOD FOR SEPARATING RADIUM FROM RADIUM-BARIUM MIXTURES

    DOEpatents

    Fuentevilla, M.E.

    1959-06-30

    An improved process is presented for separating radium from an aqueous feed solution containing radium and barium values and a complexing agent for these metals. In this process a feed solutlon containing radium and barium ions and a complexing agent for said ions ls cycled through an exchange zone in resins. The radiumenriched resin is then stripped of radium values to form a regeneration liquid, a portion of which is collected as an enriched product, the remaining portion being recycled to the exchange zone to further enrich the ion exchange resin in radium.

  12. Radical-Ion-Pair Spin Decoherence and the Quantum Efficiency of Photosynthetic Charge Separation

    NASA Astrophysics Data System (ADS)

    Kominis, Iannis; Dellis, A. T.

    2014-03-01

    We have pioneered the fundamental quantum dynamics of radical-ion-pair reactions, elucidating the basic spin-decoherence mechanism pertaining to these biochemical reactions. Radical-ion pair reactions appear in the avian magnetic compass, but more importantly, they participate in the cascade of electron-transfer reactions taking place in photosynthetic reaction centers. We will here present new insights on how the fundamental quantum dynamics of radical-ion pair reactions affect the quantum efficiency of charge separation in photosynthetic reaction centers.

  13. Ion exchange in the atomic energy industry with particular reference to actinide and fission product separation

    SciTech Connect

    Jenkins, I.L.

    1984-01-01

    Reviewed are some of the uses of ion exchange processes used by the nuclear industry for the period April, 1978 to April, 1983. The topics dealt with are: thorium, protactinium, uranium, neptunium, plutonium, americium, cesium and actinide-lanthanide separations; the higher actinides - Cm, Bk, Cf, Es and Fm; fission products; ion exchange in the geological disposal of radioactive waste. Consideration is given to safety in the use of ion exchangers and in safe methods of disposal of such materials. Full scale and pilot plant process descriptions are included as well as summaries of laboratory studies. 130 references.

  14. Quantitative separation of Hg(II) from several metal ions on Zr(IV) antimonate papers

    SciTech Connect

    Seth, N.S.; Rajput, R.P.S.; Agrawal, N.K.; Agrawal, S.K.; Agrawal, S.

    1985-09-01

    The chromatographic behavior of 32 metal ions has been studied on paper impregnated with Zirconium(IV) antimonate in aqueous HCl and mixed solvent system containing dimethylsulfoxide and dioxane. Several important binary and ternary separations have been achieved. Quantitative separation of Hg(II) from NiS , PbS , PdS , RuT , RhT , BiT , CoS , CdS and GdT is described. 6 references, 3 tables.

  15. Ion Thermal Decoupling and Species Separation in Shock-Driven Implosions

    DOE PAGESBeta

    Rinderknecht, Hans G.; Rosenberg, M. J.; Li, C. K.; Hoffman, N. M.; Kagan, G.; Zylstra, A. B.; Sio, H.; Johnson, M. Gatu; Seguin, F. H.; Petrasso, R. D.; et al

    2015-01-14

    Anomalous reduction of the fusion yields by 50% and anomalous scaling of the burn-averaged ion temperatures with the ion-species fraction has been observed for the first time in DHe3-filled shock-driven inertial confinement fusion implosions. Two ion kinetic mechanisms are used to explain the anomalous observations: thermal decoupling of the D and He3 populations and diffusive species separation. The observed insensitivity of ion temperature to a varying deuterium fraction is shown to be a signature of ion thermal decoupling in shock-heated plasmas. The burn-averaged deuterium fraction calculated from the experimental data demonstrates a reduction in the average core deuterium density, asmore » predicted by simulations that use a diffusion model. Accounting for each of these effects in simulations reproduces the observed yield trends.« less

  16. Ion Thermal Decoupling and Species Separation in Shock-Driven Implosions

    SciTech Connect

    Rinderknecht, Hans G.; Rosenberg, M. J.; Li, C. K.; Hoffman, N. M.; Kagan, G.; Zylstra, A. B.; Sio, H.; Johnson, M. Gatu; Seguin, F. H.; Petrasso, R. D.; Amendt, P.; Bellei, C.; Wilks, S.; Delettrez, J.; Glebov, V. Yu.; Stoeckl, C.; Sangster, T. C.; Meyerhofer, D. D.; Nikroo, A.

    2015-01-14

    Anomalous reduction of the fusion yields by 50% and anomalous scaling of the burn-averaged ion temperatures with the ion-species fraction has been observed for the first time in DHe3-filled shock-driven inertial confinement fusion implosions. Two ion kinetic mechanisms are used to explain the anomalous observations: thermal decoupling of the D and He3 populations and diffusive species separation. The observed insensitivity of ion temperature to a varying deuterium fraction is shown to be a signature of ion thermal decoupling in shock-heated plasmas. The burn-averaged deuterium fraction calculated from the experimental data demonstrates a reduction in the average core deuterium density, as predicted by simulations that use a diffusion model. Accounting for each of these effects in simulations reproduces the observed yield trends.

  17. Development of an atmospheric pressure ion mobility spectrometer-mass spectrometer with an orthogonal acceleration electrostatic sector TOF mass analyzer.

    PubMed

    Sysoev, Alexey A; Chernyshev, Denis M; Poteshin, Sergey S; Karpov, Alexander V; Fomin, Oleg I; Sysoev, Alexander A

    2013-10-01

    Recently developed ion mobility mass spectrometer is described. The instrument is based on a drift tube ion mobility spectrometer and an orthogonal acceleration electrostatic sector time-of-flight mass analyzer. Data collection is performed using a specially developed fast ADC-based recorder that allows real-time data integration in an interval between 3 and 100 s. Primary tests were done with positive ion electrospray. The tests have shown obtaining 100 ion mobility resolving power and 2000 mass resolving power. Obtained for 2,6-di-tert-butylpyridine in electrosprayed liquid samples during 100 s analysis and full IMS/MS data collection mode were 4 nM relative limits of detection and a 1 pg absolute limit of detection (S/N=3). Characteristic ion mobility/mass distributions were recorded for selected antibiotics, including amoxicillin, ampicillin, lomefloxacin, and ofloxacin. At studied conditions, lomefloxacin forms only a protonated molecule-producing reduced ion mobility peak at 1.082 cm(2)/(V s). Both amoxicillin and ampicillin produce [M + H](+), [M + CH3OH + H](+), and [M + CH3CN + H](+). Amoxicillin shows two peaks at 0.909 cm(2)/(V s) and 0.905 cm(2)/(V s). Ampicillin shows one peak at 0.945 cm(2)/(V s). Intensity of protonated methanol containing cluster for both ampicillin and amoxicillin has a clear tendency to rise with sample keeping time. Ofloxacin produces two peaks in the ion mobility distribution. A lower ion mobility peak at 1.051 cm(2)/(V s) is shown to be formed by [M + H](+) ions. A higher ion mobility peak appearing for samples kept more than 48 h is shown to be formed by both [M + H](+) ion and a component identified as the [M + 2H + M](+2) cluster. The cluster probably partly dissociates in the interface producing the [M + H](+) ion.

  18. Direct Separation of Molybdenum from Solid Uranium Matrices Employing Pyrohydrolysis, a Green Separation Method, and Its Determination by Ion Chromatography.

    PubMed

    Mishra, Vivekchandra G; Thakur, Uday K; Shah, Dipti J; Gupta, Neeraj K; Jeyakumar, Subbiah; Tomar, Bhupendra S; Ramakumar, Karanam L

    2015-11-01

    Pyrohydrolysis is a well-established separation method, and it is being used as a sample preparation method for several materials for further determination of non-metals such as halogens, boron, and sulfur. Analytes are retained in a diluted solution that is suitable for carrying out analysis by several determination techniques and minimizing the use of concentrated reagents. Pyrohydrolysis separation of metals has not been reported yet. The present study demonstrates the pyrohydrolysis separation of Mo as MoO4(2-) from uranium materials and its subsequent determination using ion chromatography coupled with suppressed conductivity detector. With use of TGA and XRD the volatilization behavior of Mo was studied. Important parameters for the pyrohydrolysis method required for the quantitative separation of Mo were evaluated. The precision of the method was better than 5% at 25 ppm of Mo. The accuracy was evaluated by analysis of a CRM (U3O8-ILCE-IV). The method was applied to determine Mo in ammonium diuranate samples, where the conventional methods suffer from the loss of Mo.

  19. Direct Separation of Molybdenum from Solid Uranium Matrices Employing Pyrohydrolysis, a Green Separation Method, and Its Determination by Ion Chromatography.

    PubMed

    Mishra, Vivekchandra G; Thakur, Uday K; Shah, Dipti J; Gupta, Neeraj K; Jeyakumar, Subbiah; Tomar, Bhupendra S; Ramakumar, Karanam L

    2015-11-01

    Pyrohydrolysis is a well-established separation method, and it is being used as a sample preparation method for several materials for further determination of non-metals such as halogens, boron, and sulfur. Analytes are retained in a diluted solution that is suitable for carrying out analysis by several determination techniques and minimizing the use of concentrated reagents. Pyrohydrolysis separation of metals has not been reported yet. The present study demonstrates the pyrohydrolysis separation of Mo as MoO4(2-) from uranium materials and its subsequent determination using ion chromatography coupled with suppressed conductivity detector. With use of TGA and XRD the volatilization behavior of Mo was studied. Important parameters for the pyrohydrolysis method required for the quantitative separation of Mo were evaluated. The precision of the method was better than 5% at 25 ppm of Mo. The accuracy was evaluated by analysis of a CRM (U3O8-ILCE-IV). The method was applied to determine Mo in ammonium diuranate samples, where the conventional methods suffer from the loss of Mo. PMID:26465172

  20. Chiral separation of new designer drugs (Cathinones) on chiral ion-exchange type stationary phases.

    PubMed

    Wolrab, Denise; Frühauf, Peter; Moulisová, Alena; Kuchař, Martin; Gerner, Christopher; Lindner, Wolfgang; Kohout, Michal

    2016-02-20

    We present the enantioseparation of new designer drugs from the cathinone family on structurally different chiral ion-exchange type stationary phases. A novel strong cation-exchange type chiral stationary phase was synthesized and its performance compared with previously reported ion-exchange type chiral stationary phases. The influence of structural elements of the chiral selectors on their chromatographic performance was studied and the possibilities of tuning chromatographic parameters by varying the polarity of the employed mobile phases were determined. Evidence is provided that a change in mobile phase composition strongly influences the solvation shell of the polarized and polarizable units of the selectors and analytes, as well as ionizable mobile phase additives. Furthermore, the structural features of the selectors (e.g. the size of aromatic units and their substitution pattern) are shown to play a key role in the effective formation of diastereomeric complexes with analytes. Thus, we have achieved the enantioseparation of all test analytes with a mass spectrometry-compatible mobile phase with a chiral strong cation-exchange type stationary phase.

  1. A new method based on electrospray ionisation ion mobility spectrometry (ESI-IMS) for simultaneous determination of caffeine and theophylline.

    PubMed

    Jafari, M T; Rezaei, B; Javaheri, M

    2011-06-15

    In this work for the first time, simultaneous analysis of caffeine and theophylline was done by ion mobility spectrometry (IMS) only, without a powerful separation technique (e.g., HPLC). Ion mobility spectrometry with low cost, inexpensive maintenance and very fast analysis makes an attractive technique for the simultaneous determination of the caffeine and theophylline in foodstuff samples and biological matrices. In this study, the extraction protocol using molecular imprinted polymer-solid phase extraction (MIP-SPE) was successfully used to directly extract caffeine and theophylline from real samples. The results obtained provided the detection limits of 0.2 and 0.3μgmL(-1) for caffeine and theophylline, respectively. The linear dynamic range of about two orders of magnitude was obtained for these compounds. Also, the proposed method was used to analyse various real samples of green tea and spiked human plasma, and the obtained results confirmed the capability of ESI-IMS for simultaneous detection of caffeine and theophylline.

  2. Separation of Lanthanide Ions with Kläui Ligand Resin

    SciTech Connect

    Granger, Trinity D.; Henry, Victoria A.; Latesky, Stanley

    2007-07-01

    Separation and pre-concentration of the desired analyte is often a critical step in many radioanalytical methods. Current procedures for separating and concentrating analytes for detection are complex, and can be both expensive and time consuming. Therefore, the purpose of this research is to develop an alternative method of separating lanthanide ions through the use of an extraction chromatography resin containing a Klaui ligand salt. This research is a continuation of a concerted effort to develop new methods of detecting small concentrations of radionuclides and lanthanides using Klaui ligands. The Klaui ligands, C5Me5Co(OP(OR)2)3- (R=Me, Et, n-Pr) (LOR-), have unique affinity for lanthanide and actinide ions in the presence of competing metal ions. The use of 1 wt% NaLOR (R=Et or n-Pr) adsorbed onto resin support has been shown to extract lanthanide ions from aqueous nitric acid solutions of different concentrations. In order to further evaluate the utility of these materials in radiochemical separation, the selectivity of the resins for the different lanthanide ions was examined by measuring the distribution coefficients (Kd) for a series of lanthanides over a range of solution conditions. Based on prior research with actinide ions, it was hypothesized that the lanthanide ions would bond strongly with the Klaui ligands. The success of this research is important, because it will assist in expanding and improving current automated radiochemical methods, which will decrease the cost of developing and implementing radiochemical methods. To date, Kd values have been determined for Eu+3, Nd+3 and Pr+3 under varying nitric acid (HNO3) concentration, using a resin consisting of 1.0 wt% NaLOPr on Amberlite XAD-7HP. The dependence of the Kd values for Eu+3 has also been examined as a function of the ligand-to-europium ratio and the nitrate concentration. Decreasing Kd values were obtained upon increasing the nitric acid concentration, indicating protonation of the

  3. Enhanced sensitivity and selectivity in a dual cell ion mobility spectrometer

    NASA Astrophysics Data System (ADS)

    Griffin, Matthew T.; Fulton, Jack E., Jr.; McAtee, Robert F.; Gao, Rong; Tsoukalas, Lefteri H.

    2003-08-01

    While ion mobility spectrometry (IMS) has been used as a portable trace vapor detector, these handheld systems suffer from poor selectivity. Their low resolution makes confident identification of chemical species difficult. One major application for these IMS systems is in Homeland Defense. IMS systems are fielded for the detection of chemical warfare agents, explosives, narcotics, and other hazardous chemicals. Recently, a novel signal processing methodology using wavelet filtering, statistical evaluators, and genetic algorithms was demonstrated to improve sensitivity and specificity of an ion mobility spectrometer. Previous work involved a single (single polarity) IMS cell. Since both positive and negative ions are created in the same environment and a common sample interface is used for the dual IMS system, there is cross talk between the positive and negative cell. Typically, this cross talk provides little information on the identity of the chemical species present. However, using this new methodology, valuable sample information is obtained. Moreover, ion beam modulation has been incorporated to allow for the ion beam to be broken up into discrete packets. The modulation allows the rejection of common background interferents. This paper will present the process of using cell cross talk, ion beam modulation, and application and extension of the signal processing methodology. The application to field instrumentation will also be discussed.

  4. Developing Fieldable Systems for Chemical Sensing Using Field Asymmetric Ion Mobility Spectrometry and Mass Spectrometry

    SciTech Connect

    Kevin Kyle, Stephan Weeks, R. Trainham

    2008-03-01

    Currently, there is an urgent need for field-rugged and field-programmable sensor systems that provide highly selective, universal monitoring of vapors and aerosols at detectable levels from persons or areas involved with illicit chemical/biological/explosives (CBE) production. These devices must be portable, low cost, robust, and provide accurate measurements to avoid both false positive and negative results. Furthermore, the information provided by the devices must be received in a timely manner so that informed decisions can be immediately made and the appropriate actions taken. Two technologies that are unparalleled in their sensitivity, selectivity, and trace-level detection capabilities are field asymmetric ion mobility spectrometry (FAIMS) and mass spectrometry. Here, we will show progress that has been made toward developing fieldable FAIMS systems and mass spectrometers. Working in collaboration with Sionex Corporation, the microDMx detector was equipped with a continuous air sampling system to develop selective methods for the analysis of compounds of interest. A microdiaphragm pump (KNF Neuberger, Inc.) is used to pull in gas-phase analytes directly from the air for separation and detection with the FAIMS system. The FAIMS evaluation platform (SVAC) unit currently measures 9.8-inch x 4.6-inch x 3.2-inch, weighs 3.1 lb, and utilizes a {sup 63}Ni source to ionize incoming compounds. Analytes entering the unit are separated and identified by their characteristic response to the compensation voltage (V{sub c}) at a given rf field strength (V{sub rf}). This response has been observed to be unique for a wide range of substances studied. If additional verification were required or a targeted analyte present in a complex chemical matrix, a FAIMS unit equipped with a fast gas chromatography column has been evaluated. The unit combines the separation capabilities of gas chromatography with the selectivity of FAIMS. It measures 9.5-inch x 5.25-inch x 3.5-inch

  5. A two-phase approach to Fourier transform ion mobility time-of-flight mass spectrometry.

    PubMed

    Clowers, Brian H; Siems, William F; Yu, Zhihao; Davis, Austen L

    2015-10-21

    It is well known that the duty cycle of common drift-tube ion mobility experiments is often below 1%. However, multiplexing approaches such as Fourier and Hadamard pulsing schemes have been shown to independently enhance the throughput of ion mobility spectrometry (IMS) experiments to levels that approach 50%. While challenges remain to their broad scale implementation we describe a new Fourier transform (FT) IMS experiment that is directly compatible with standard drift tube ion mobility mass spectrometers (DT-IMMS). Compared to previous FT-IMS experiments, our new approach requires only a single gate and circumvents the need for signal apodization by combining data from two frequency pulsing sequences 180° out of phase. Assessment of our initial results highlights an increase in signal-to-noise (SNR) relative to both previous implementations FT-IMS experiments and signal averaged (SA) experiments. For select tetraalkylammonium salts SNR improvements of more than one order of magnitude are routinely possible. To explore the performance metrics associated with the technique a number of experimental variables were systematically altered including frequency sweep range, sweep time, and data acquisition time. Using this experimental design we present the key aspects, considerations, and minimum resources necessary for other IMS researchers to incorporate this operational mode into their research. The two-phase FT-IMMS technique offers a tractable mechanism to enhance sensitivity for IMMS measurements and its broad-scale adoption by IMMS researchers promises to enhance the acquisition speed for mobility measurements using hybrid instrumentation.

  6. Affecting proton mobility in activated peptide and whole protein ions via lysine guanidination.

    PubMed

    Pitteri, Sharon J; Reid, Gavin E; McLuckey, Scott A

    2004-01-01

    We have evaluated the effect of lysine guanidination in peptides and proteins on the dissociation of protonated ions in the gas phase. The dissociation of guanidinated model peptide ions compared to their unmodified forms showed behavior consistent with concepts of proton mobility as a major factor in determining favored fragmentation channels. Reduction of proton mobility associated with lysine guanidination was reflected by a relative increase in cleavages occurring C-terminal to aspartic acid residues as well as increases in small molecule losses. To evaluate the effect of guanidination on the dissociation behavior of whole protein ions, bovine ubiquitin was selected as a model. Essentially, all of the amide bond cleavages associated with the +10 charge state of fully guanidinated ubiquitin were observed to occur C-terminal to aspartic acid residues, unlike the dissociation behavior of the +10 ion of the unmodified protein, where competing cleavage N-terminal to proline and nonspecific amide bond cleavages were also observed. The +8 and lower charge states of the guanidinated protein showed prominent losses of small neutral molecules. This overall fragmentation behavior is consistent with current hypotheses regarding whole protein dissociation that consider proton mobility and intramolecular charge solvation as important factors in determining favored dissociation channels, and are also consistent with the fragmentation behaviors observed for the guanidinated model peptide ions. Further evaluation of the utility of condensed phase guanidination of whole proteins is necessary but the results described here confirm that guanidination can be an effective strategy for enhancing C-terminal aspartic acid cleavages. Gas phase dissociation exclusively at aspartic acid residues, especially for whole protein ions, could be useful in identifying and characterizing proteins via tandem mass spectrometry of whole protein ions.

  7. Analysis of heterogeneous water vapor uptake by metal iodide cluster ions via differential mobility analysis-mass spectrometry

    SciTech Connect

    Oberreit, Derek; Rawat, Vivek K.; Larriba-Andaluz, Carlos; Ouyang, Hui; McMurry, Peter H.; Hogan, Christopher J.

    2015-09-14

    The sorption of vapor molecules onto pre-existing nanometer sized clusters is of importance in understanding particle formation and growth in gas phase environments and devising gas phase separation schemes. Here, we apply a differential mobility analyzer-mass spectrometer based approach to observe directly the sorption of vapor molecules onto iodide cluster ions of the form (MI){sub x}M{sup +} (x = 1-13, M = Na, K, Rb, or Cs) in air at 300 K and with water saturation ratios in the 0.01-0.64 range. The extent of vapor sorption is quantified in measurements by the shift in collision cross section (CCS) for each ion. We find that CCS measurements are sensitive enough to detect the transient binding of several vapor molecules to clusters, which shift CCSs by only several percent. At the same time, for the highest saturation ratios examined, we observed CCS shifts of up to 45%. For x < 4, cesium, rubidium, and potassium iodide cluster ions are found to uptake water to a similar extent, while sodium iodide clusters uptake less water. For x ≥ 4, sodium iodide cluster ions uptake proportionally more water vapor than rubidium and potassium iodide cluster ions, while cesium iodide ions exhibit less uptake. Measured CCS shifts are compared to predictions based upon a Kelvin-Thomson-Raoult (KTR) model as well as a Langmuir adsorption model. We find that the Langmuir adsorption model can be fit well to measurements. Meanwhile, KTR predictions deviate from measurements, which suggests that the earliest stages of vapor uptake by nanometer scale species are not well described by the KTR model.

  8. Analysis of heterogeneous water vapor uptake by metal iodide cluster ions via differential mobility analysis-mass spectrometry.

    PubMed

    Oberreit, Derek; Rawat, Vivek K; Larriba-Andaluz, Carlos; Ouyang, Hui; McMurry, Peter H; Hogan, Christopher J

    2015-09-14

    The sorption of vapor molecules onto pre-existing nanometer sized clusters is of importance in understanding particle formation and growth in gas phase environments and devising gas phase separation schemes. Here, we apply a differential mobility analyzer-mass spectrometer based approach to observe directly the sorption of vapor molecules onto iodide cluster ions of the form (MI)xM(+) (x = 1-13, M = Na, K, Rb, or Cs) in air at 300 K and with water saturation ratios in the 0.01-0.64 range. The extent of vapor sorption is quantified in measurements by the shift in collision cross section (CCS) for each ion. We find that CCS measurements are sensitive enough to detect the transient binding of several vapor molecules to clusters, which shift CCSs by only several percent. At the same time, for the highest saturation ratios examined, we observed CCS shifts of up to 45%. For x < 4, cesium, rubidium, and potassium iodide cluster ions are found to uptake water to a similar extent, while sodium iodide clusters uptake less water. For x ≥ 4, sodium iodide cluster ions uptake proportionally more water vapor than rubidium and potassium iodide cluster ions, while cesium iodide ions exhibit less uptake. Measured CCS shifts are compared to predictions based upon a Kelvin-Thomson-Raoult (KTR) model as well as a Langmuir adsorption model. We find that the Langmuir adsorption model can be fit well to measurements. Meanwhile, KTR predictions deviate from measurements, which suggests that the earliest stages of vapor uptake by nanometer scale species are not well described by the KTR model. PMID:26374028

  9. Classification of Ion Mobility Data Using the Neural Network Approach

    NASA Technical Reports Server (NTRS)

    Duong, T. A.; Kanik, I.

    2005-01-01

    Determination of atmospheric and surface elemental and molecular composition of various solar system bodies is essential to the development of a firm understanding of the origin and evolution of the solar system. Furthermore, such data is needed to address the intriguing question of whether or not life exists or once existed elsewhere in the Solar System. As such, these measurements are among the primary scientific goals of NASA s current and future planetary missions. In recent years, significant progress toward both miniaturization and field portability of in situ analytical separation and detection devices have been made with future planetary explorations in mind. However, despite all these advances, accurate in situ identification of atmospheric and surface compounds remains a big challenge. In response to that we are developing various hardware and software tools which would enable us to uniquely identify species of interest in a complex chemical environment.

  10. Separation of low concentration of cesium ion from wastewater by electrochemically switched ion exchange method: experimental adsorption kinetics analysis.

    PubMed

    Sun, Bin; Hao, Xiao-Gang; Wang, Zhong-De; Guan, Guo-Qing; Zhang, Zhong-Lin; Li, Yi-Bin; Liu, Shi-Bin

    2012-09-30

    A series of experiments were performed to evaluate the continuous separation of cesium based on an electrochemically switched ion exchange (ESIX) process using a diaphragm-isolated reactor with two identical nickel hexacyanoferrate/porous three-dimensional carbon felt (NiHCF/PTCF) electrodes as working electrodes. The effects of applied potential, initial concentrations and pH values of the simulation solutions on the adsorption of cesium ion were investigated. The adsorption rate of cesium ion in the ESIX process was fitted by a pseudo-first-order reaction model. The experiments revealed that the introduction of applied potential on the electrodes greatly enhanced the adsorption/desorption rate of Cs(+) and increased the separation efficiency. H(3)O(+) was found to play a dual role of electrolyte and competitor, and the adsorption rate constant showed a curve diversification with an increase in pH value. Also, it was found that the electrochemically switched adsorption process of Cs(+) by NiHCF/PTCF electrodes proceeded in two main steps, i.e., an ESIX step with a fast adsorption rate and an ion diffusion step with a slow diffusion rate. Meanwhile, the NiHCF/PTCF film electrode showed adsorption selectivity for Cs(+) in preference to Na(+).

  11. Separation of low concentration of cesium ion from wastewater by electrochemically switched ion exchange method: experimental adsorption kinetics analysis.

    PubMed

    Sun, Bin; Hao, Xiao-Gang; Wang, Zhong-De; Guan, Guo-Qing; Zhang, Zhong-Lin; Li, Yi-Bin; Liu, Shi-Bin

    2012-09-30

    A series of experiments were performed to evaluate the continuous separation of cesium based on an electrochemically switched ion exchange (ESIX) process using a diaphragm-isolated reactor with two identical nickel hexacyanoferrate/porous three-dimensional carbon felt (NiHCF/PTCF) electrodes as working electrodes. The effects of applied potential, initial concentrations and pH values of the simulation solutions on the adsorption of cesium ion were investigated. The adsorption rate of cesium ion in the ESIX process was fitted by a pseudo-first-order reaction model. The experiments revealed that the introduction of applied potential on the electrodes greatly enhanced the adsorption/desorption rate of Cs(+) and increased the separation efficiency. H(3)O(+) was found to play a dual role of electrolyte and competitor, and the adsorption rate constant showed a curve diversification with an increase in pH value. Also, it was found that the electrochemically switched adsorption process of Cs(+) by NiHCF/PTCF electrodes proceeded in two main steps, i.e., an ESIX step with a fast adsorption rate and an ion diffusion step with a slow diffusion rate. Meanwhile, the NiHCF/PTCF film electrode showed adsorption selectivity for Cs(+) in preference to Na(+). PMID:22819476

  12. Ion mobility imaging and contrast mechanism of apparent conductivity in MREIT.

    PubMed

    Oh, Tong In; Kim, Young Tae; Minhas, Atul; Seo, Jin Keun; Kwon, Oh In; Woo, Eung Je

    2011-04-01

    Magnetic resonance electrical impedance tomography (MREIT) aims to produce high-resolution cross-sectional images of conductivity distribution inside the human body. Injected current into an imaging object induces a distribution of internal magnetic flux density, which is measured by using an MRI scanner. We can reconstruct a conductivity image based on its relation with the measured magnetic flux density. In this paper, we explain the contrast mechanism in MREIT by performing and analyzing a series of numerical simulations and imaging experiments. We built a stable conductivity phantom including a hollow insulating cylinder with holes. Filling both inside and outside the hollow cylinder with the same saline, we controlled ion mobilities to create a conductivity contrast without being affected by the ion diffusion process. From numerical simulations and imaging experiments, we found that slopes of induced magnetic flux densities change with hole diameters and therefore conductivity contrasts. Associating the hole diameter with apparent conductivity of the region inside the hollow cylinder with holes, we could experimentally validate the contrast mechanism in MREIT. Interpreting reconstructed apparent conductivity images of the phantom as ion mobility images, we discuss the meaning of the apparent conductivity seen by a certain probing method. In designing MREIT imaging experiments, the ion mobility imaging method using the proposed stable conductivity phantom will enable us to estimate a distinguishable conductivity contrast for a given set of imaging parameters. PMID:21411866

  13. Synthesis of Anomeric Methyl Fructofuranosides and Their Separation on an Ion-Exchange Resin

    ERIC Educational Resources Information Center

    Nurminen, Erkki; Poijarvi, Paivi; Koskua, Katja; Hovinen, Jari

    2007-01-01

    Treatment of d-fructose with methanol in the presence of acid as a catalyst gives a mixture of methyl-[beta]-d-fructopyranoside, methyl-[alpha]-D-fructofuranoside, and methyl-[beta]-d-fructofuranoside, which were separated on an ion exchange column and characterized polarimetrically.

  14. Separation of polar betalain pigments from cacti fruits of Hylocereus polyrhizus by ion-pair high-speed countercurrent chromatography.

    PubMed

    Wybraniec, Sławomir; Stalica, Paweł; Jerz, Gerold; Klose, Bettina; Gebers, Nadine; Winterhalter, Peter; Spórna, Aneta; Szaleniec, Maciej; Mizrahi, Yosef

    2009-10-01

    Polar betacyanin pigments together with betaxanthins from ripe cactus fruits of Hylocereus polyrhizus (Cactaceae) were fractionated by means of preparative ion-pair high-speed countercurrent chromatography (IP-HSCCC) also using the elution-extrusion (EE) approach for a complete pigment recovery. HSCCC separations were operated in the classical 'head-to-tail' mode with an aqueous mobile phase. Different CCC solvent systems were evaluated in respect of influence and effectiveness of fractionation capabilities to separate the occurring pigment profile of H. polyrhizus. For that reason, the additions of two different volatile ion-pair forming perfluorinated carboxylic acids (PFCA) were investigated. For a direct comparison, five samples of Hylocereus pigment extract were run on preparative scale (900 mg) in 1-butanol-acetonitrile-aqueous TFA 0.7% (5:1:6, v/v/v) and the modified systems tert.-butyl methyl ether-1-butanol-acetonitrile-aqueous PFCA (2:2:1:5, v/v/v/v) using 0.7% and 1.0% trifluoroacetic acid (TFA) or heptafluorobutyric acid (HFBA) in the aqueous phase, respectively. The chemical affinity to the organic stationary CCC solvent phases and in consequence the retention of these highly polar betalain pigments was significantly increased by the use of the more lipophilic fluorinated ion-pair reagent HFBA instead of TFA. The HFBA additions separated more effectively the typical cacti pigments phyllocactin and hylocerenin from betanin as well as their iso-forms. Unfortunately, similar K(D) ratios and selectivity factors alpha around 1.0-1.1 in all tested solvent systems proved that the corresponding diastereomers, 15S-type pigments cannot be resolved from the 15R-epimers (iso-forms). Surprisingly, additions of the stronger ion-pair reagent (HFBA) resulted in a partial separation of hylocerenin from phyllocactin which were not resolved in the other solvent systems. The pigments were detected by means of HPLC-DAD and HPLC-electrospray ionization-MS using also

  15. The influence of ion/molecule reactions on the evaluation of ion mobility and diffusion coefficients

    NASA Astrophysics Data System (ADS)

    de Urquijo, J.; Alvarez, I.; Cisneros, C.; Martinez, H.

    1996-05-01

    This paper deals with the evaluation of the mean and the variance of the ion flux at the exit of a drift tube, from which the drift velocity, [nu]d, and the longitudinal diffusion coefficient, DL, can be derived. Besides drift and diffusion, the presence of a primary ion conversion process through reactions with the gas is fully considered from the outset. Full expressions for the mean and variance of the ion flux are then approximated by resorting to experimental conditions in which low ionic reactivity, adequate drift tube geometry, and other experimental conditions are met, thus arriving at very simple expressions from which [nu]d and DL are derived. These simple expressions have been obtained previously from analyses ignoring ion/molecule reactions from the outset. The full expressions derived here and their approximations are used to provide a means of evaluating the errors incurred when very simple expressions are used in highly reacting ion/neutral systems.

  16. Mobility and fluorescence of barium ions in xenon gas for the exo experiment

    NASA Astrophysics Data System (ADS)

    Benitez Medina, Julio Cesar

    The Enriched Xenon Observatory (EXO) is an experiment which aims to observe the neutrinoless double beta decay of 136Xe. The measurement of this decay would give information about the absolute neutrino mass and whether or not the neutrino is its own antiparticle. Since this is a very rare decay, the ability to reject background events by detecting the barium ion daughter from the double beta decay would be a major advantage. EXO is currently operating a detector with 200 kg of enriched liquid xenon, and there are plans to build a ton scale xenon detector. Measurements of the purity of liquid xenon in our liquid xenon test cell are reported. These results are relevant to the research on detection of single barium ions by our research group at Colorado State University. Details of the operation of the purity monitor are described. The effects of using a purifier, recirculation and laser ablation on the purity of liquid xenon are discussed. Mobility measurements of barium in xenon gas are reported for the first time. The variation of mobility with xenon gas pressure suggests that a significant fraction of molecular ions are formed when barium ions interact with xenon gas at high pressures. The measured mobility of Ba+ in Xe gas at different pressures is compared with the predicted theoretical value, and deviations are explained by a model that describes the fraction of molecular ions in Xe gas as a function of pressure. The results are useful for the analysis of experiments of fluorescence of Ba+ in xenon gas. It is also important to know the mobility of the ions in order to calculate the time they interact with an excitation laser in fluorescence experiments and in proposed 136 Ba+ daughter detection schemes. This thesis presents results of detection of laser induced fluorescence of Ba+ ions in Xe gas. Measurements of the pressure broadening of the excitation spectra of Ba+ in xenon gas are presented. Nonradiative decays due to gas collisions and optical pumping

  17. Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin.

    PubMed

    Wang, Xiaojun; Zhuang, Jingshun; Fu, Yingjuan; Tian, Guoyu; Wang, Zhaojiang; Qin, Menghua

    2016-04-01

    A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL. PMID:26859331

  18. Properties of solvate shells and the mobility of ions, according to molecular dynamics data

    NASA Astrophysics Data System (ADS)

    Lankin, A. V.; Norman, G. E.; Orekhov, M. A.

    2016-05-01

    The solvate shells of an ion, its velocity autocorrelation function, and diffusion coefficient D are found, and the interrelations between them are analyzed. A single ion in the system of atoms of a liquid is considered a model system. The interaction between the ion and atoms of the liquid is described by polarization potential U( r); the interaction between atoms of the liquid alone is described by the Lennard-Jones potential. A classical molecular dynamics method is used. Five solvate shells around the ion are found, and the lifetimes of atoms on each shell are calculated. It is found that the velocity autocorrelation function is of a vibrating nature. The spectrum of the autocorrelator and the frequency of cluster vibrations in a linear approximation are compared. Dependences D on parameters of potential U( r) are found. No dependence D on the ion mass is found; this is explained by solvation. The Einstein-Stokes formula and the HSK approximation are used in discussing the results. It is shown that at small radii of the ion, dependence D on parameters U( r) is described by such a model. When the ion radius is increased, the deviation from this dependence and an increase in D are observed. The results are compared to experimental mobilities of O 2 - and Ar 2 + ions in liquid argon.

  19. Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis

    USGS Publications Warehouse

    Ball, J.W.; Bassett, R.L.

    2000-01-01

    A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

  20. Surface-modified separators prepared with conductive polymer and aluminum fluoride for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Shin, Won-Kyung; Yoo, Ji-Hyun; Kim, Dong-Won

    2015-04-01

    Conventional polyethylene (PE) separators are surface-modified by thin coating with conductive poly(3,4-ethylenedioxythiophen)-co-poly(ethylene glycol) (PEDOT-co-PEG) copolymer and aluminum fluoride particles. The surface-modified separators exhibit a significant reduction in thermal shrinkage and an improved electrolyte uptake. By using these separators, the lithium-ion cells composed of carbon negative electrodes and LiNi1/3Co1/3Mn1/3O2 positive electrodes are assembled and their cycling performances are evaluated. The cells assembled with the surface-modified separators demonstrate superior cycling performance compared to cells prepared with pristine PE separator, both at ambient temperatures and at elevated temperature.

  1. Recovery of lithium and cobalt from waste lithium ion batteries of mobile phone

    SciTech Connect

    Jha, Manis Kumar Kumari, Anjan; Jha, Amrita Kumari; Kumar, Vinay; Hait, Jhumki; Pandey, Banshi Dhar

    2013-09-15

    Graphical abstract: Recovery of valuable metals from scrap batteries of mobile phone. - Highlights: • Recovery of Co and Li from spent LIBs was performed by hydrometallurgical route. • Under the optimum condition, 99.1% of lithium and 70.0% of cobalt were leached. • The mechanism of the dissolution of lithium and cobalt was studied. • Activation energy for lithium and cobalt were found to be 32.4 kJ/mol and 59.81 kJ/mol, respectively. • After metal recovery, residue was washed before disposal to the environment. - Abstract: In view of the stringent environmental regulations, availability of limited natural resources and ever increasing need of alternative energy critical elements, an environmental eco-friendly leaching process is reported for the recovery of lithium and cobalt from the cathode active materials of spent lithium-ion batteries of mobile phones. The experiments were carried out to optimize the process parameters for the recovery of lithium and cobalt by varying the concentration of leachant, pulp density, reductant volume and temperature. Leaching with 2 M sulfuric acid with the addition of 5% H{sub 2}O{sub 2} (v/v) at a pulp density of 100 g/L and 75 °C resulted in the recovery of 99.1% lithium and 70.0% cobalt in 60 min. H{sub 2}O{sub 2} in sulfuric acid solution acts as an effective reducing agent, which enhance the percentage leaching of metals. Leaching kinetics of lithium in sulfuric acid fitted well to the chemical controlled reaction model i.e. 1 − (1 − X){sup 1/3} = k{sub c}t. Leaching kinetics of cobalt fitted well to the model ‘ash diffusion control dense constant sizes spherical particles’ i.e. 1 − 3(1 − X){sup 2/3} + 2(1 − X) = k{sub c}t. Metals could subsequently be separated selectively from the leach liquor by solvent extraction process to produce their salts by crystallization process from the purified solution.

  2. Unfolding of Hydrated Alkyl Diammonium Cations Revealed by Cryogenic Ion Mobility-Mass Spectrometry.

    PubMed

    Servage, Kelly A; Fort, Kyle L; Silveira, Joshua A; Shi, Liuqing; Clemmer, David E; Russell, David H

    2015-07-22

    Hydration of the ammonium ion plays a key role in determining the biomolecular structure as well as local structure of water in aqueous environments. Experimental data obtained by cryogenic ion mobility-mass spectrometry (cryo-IM-MS) show that dehydration of alkyl diammonium cations induces a distinct unfolding transition at a critical number of water molecules, n = 21 to 23, n = 24 to 26, and n = 27 to 29, for 1,7-diaminoheptane, 1,8-diaminooctane, and 1,10-diaminodecane, respectively. Results are also presented that reveal compelling evidence for unique structural transitions of hydrated ammonium ions associated with the development of the hydrogen-bond network around individual charged groups. The ability to track the evolution of structure upon stepwise dehydration provides direct insight into the intricate interplay between solvent-molecule interactions that are responsible for defining conformations. Such insights are potentially valuable in understanding how ammonium ion solvation influences conformation(s) of larger biomolecules.

  3. Studies on Molecular and Ion Transport in Silicalite Membranes and Applications as Ion Separator for Redox Flow Battery

    NASA Astrophysics Data System (ADS)

    Yang, Ruidong

    Microporous zeolite membranes have been widely studied for molecular separations based on size exclusion or preferential adsorption-diffusion mechanisms. The MFI-type zeolite membranes were also demonstrated for brine water desalination by molecular sieving effect. In this research, the pure silica MFI-type zeolite (i.e. silicalite) membrane has been for the first time demonstrated for selective permeation of hydrated proton (i.e. H3O+) in acidic electrolyte solutions. The silicalite membrane allows for permeation of H 3O+ ions, but is inaccessible to the large hydrated multivalent vanadium ions due to steric effect. The silicalite membrane has been further demonstrated as an effective ion separator in the all-vanadium redox flow battery (RFB).The silicalite is nonionic and its proton conductivity relies on the electric field-driven H3O+ transport through the sub nanometer-sized pores under the RFB operation conditions. The silicalite membrane displayed a significantly reduced self-discharge rate because of its high proton-to-vanadium ion transport selectivity. However, the nonionic nature of the silicalite membrane and very small diffusion channel size render low proton conductivity and is therefore inefficient as ion exchange membranes (IEMs) for practical applications. The proton transport efficiency may be improved by reducing the membrane thickness. However, the zeolite thin films are extremely fragile and must be supported on mechanically strong and rigid porous substrates. In this work, silicalite-Nafion composite membranes were synthesized to achieve a colloidal silicalite skin on the Nafion thin film base. The "colloidal zeolite-ionic polymer" layered composite membrane combines the advantages of high proton-selectivity of the zeolite layer and the mechanical flexibility and low proton transport resistance of the ionic polymer membrane. The composite membrane exhibited higher proton/vanadium ion separation selectivity and lower electrical resistance than

  4. Express analysis of explosives, chemical warfare agents and drugs with multicapillary column gas chromatography and ion mobility increment spectrometry.

    PubMed

    Buryakov, Igor A

    2004-02-01

    Description of a gas chromatograph designed for express analysis of explosives (2,4-dinitrotoluene, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate), chemical warfare agents (mustard gas, lewisite, sarin) and drugs (heroin, cocaine hydrochloride, crack) is given. The devices comprises a multicapillary chromatographic column and an ion mobility increment spectrometer (MCC-IMIS). The main analytical characteristics of an IMIS (estimated detection limit (DL), linear dynamic range (LDR), speed of response) and a chromatographic column (separation power, degree of separation, a number of possible peaks at a chromatogram section, divided by analysis time) are determined. The maximum value of DL equal to 5 pg/ml was registered for cis-alpha-LW, and the lowest one of 0.001 pg/ml was for cocaine. The maximum value of LDR equal to 1000 was registered for sarin and the lowest one of 150 was for the ions of lewisite. Speed of response of one compound detection with the IMIS was 0.7 s. PMID:14698239

  5. Electrokinetic power generation by means of streaming potentials: a mobile-ion-drain method to increase the streaming potentials.

    PubMed

    Yang, Jun; Lu, Fuzhi; Kostiuk, Larry W; Kwok, Daniel Y

    2005-04-01

    We show, by natural occurring phenomena of charge separation near the solid-liquid interface in microchannels, that electricity can be generated by forcing water through a ceramic rod with no moving part and emission. A single hand push on a syringe is our source of power which easily generates a streaming potential of over 20 V and a streaming current of 30 microA. By means of streaming potentials, two capacitors were charged and discharged alternatively to light-up two Light-Emitting-Diodes in every ten seconds. From our specific choice of liquid/solid pair, an efficiency of 0.8% was obtained. A mobile-ion-drain method is also demonstrated to increase the streaming potential.

  6. Selective pretreatment and determination of phenazopyridine using an imprinted polymer-electrospray ionization ion mobility spectrometry system.

    PubMed

    Rezaei, B; Jafari, M T; Rahmanian, O

    2011-01-15

    In this research, selective separation and determination of phenazopyridine (PAP) is demonstrated using molecular imprinted polymer (MIP) coupled with electrospray ionization ion mobility spectrometry (ESI-IMS). In the non-covalent approach, selective MIP produced using PAP and methacrylic acid (MAA) as a template molecule and monomer, respectively. The created polymer is utilized as a media for solid-phase extraction (SPE), revealing selective binding properties for the analyte from pharmaceutical and serum samples. A coupled MIP-IMS makes it possible to quantitize PAP in the range of 1-100 ng mL(-1) and with a 0.2 ng mL(-1) detection limit. Furthermore, the MIP selectivity is evaluated by application of some substances with analogous and different molecular structures to that of PAP. This method is successfully applied for the determination of PAP in pharmaceutical and serum samples.

  7. Diurnal variation in the concentration of air ions of different mobility classes in a rural area

    NASA Astrophysics Data System (ADS)

    Hõrrak, Urmas; Salm, Jaan; Tammet, Hannes

    2003-10-01

    Analyzed data consist of 8900 hourly average mobility distributions measured in the mobility range of 0.00041-3.2 cm2 V-1 s-1 (diameter range 0.36-79 nm) at Tahkuse Observatory, Estonia, in 1993-1994. The average diurnal variation in the concentration of cluster ions is typical for continental stations: the maximum in the early morning hours and the minimum in the afternoon. This is explained by variations in radon concentration. The diurnal variation for big cluster ions (0.5-1.3 cm2 V-1 s-1) differs from that for small cluster ions (1.3-3.14 cm2 V-1 s-1). The size distribution of intermediate and light large ions in the range of 1.6-22 nm is strongly affected by nucleation bursts of nanometer particles. On the burst days, the maximum concentration of intermediate ions (1.6-7.4 nm) is about the noontime and that of light large ions (7.4-22 nm) about 2 hours later. The concentration of heavy large ions (charged Aitken particles of diameters of 22-79 nm) is enhanced in the afternoon and this is explained by the bursts of nanometer particles and the subsequent growth of particles by condensation and coagulation. If the burst days are excluded, then in the warm season the concentration of Aitken particles increases during night. In the cold season, the diurnal variation is different and all the classes of aerosol ions (2.1-79 nm) show similar variation with the minimum at 0600 LT and the maximum in the afternoon; exceptions are the rare nucleation burst days.

  8. Linking molecular models with ion mobility experiments. Illustration with a rigid nucleic acid structure

    PubMed Central

    D'Atri, Valentina; Porrini, Massimiliano; Rosu, Frédéric; Gabelica, Valérie

    2015-01-01

    Ion mobility spectrometry experiments allow the mass spectrometrist to determine an ion's rotationally averaged collision cross section ΩEXP. Molecular modelling is used to visualize what ion three-dimensional structure(s) is(are) compatible with the experiment. The collision cross sections of candidate molecular models have to be calculated, and the resulting ΩCALC are compared with the experimental data. Researchers who want to apply this strategy to a new type of molecule face many questions: (1) What experimental error is associated with ΩEXP determination, and how to estimate it (in particular when using a calibration for traveling wave ion guides)? (2) How to generate plausible 3D models in the gas phase? (3) Different collision cross section calculation models exist, which have been developed for other analytes than mine. Which one(s) can I apply to my systems? To apply ion mobility spectrometry to nucleic acid structural characterization, we explored each of these questions using a rigid structure which we know is preserved in the gas phase: the tetramolecular G-quadruplex [dTGGGGT]4, and we will present these detailed investigation in this tutorial. © 2015 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons Ltd. PMID:26259654

  9. Analysis of explosives using corona discharge ionization combined with ion mobility spectrometry-mass spectrometry.

    PubMed

    Lee, Jihyeon; Park, Sehwan; Cho, Soo Gyeong; Goh, Eun Mee; Lee, Sungman; Koh, Sung-Suk; Kim, Jeongkwon

    2014-03-01

    Corona discharge ionization combined with ion mobility spectrometry-mass spectrometry (IMS-MS) was utilized to investigate five common explosives: cyclonite (RDX), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclotetramethylenetetranitramine (HMX), and 2,4-dinitrotoluene (DNT). The MS scan and the selected ion IMS analyses confirmed the identities of the existing ion species and their drift times. The ions observed were RDX·NO3(-), TNT(-), PETN·NO3(-), HMX·NO3(-), and DNT(-), with average drift times of 6.93 ms, 10.20 ms, 9.15 ms, 12.24 ms, 11.30 ms, and 8.89 ms, respectively. The reduced ion mobility values, determined from a standard curve calculated by linear regression of (normalized drift times)(-1) versus literature K0 values, were 2.09, 1.38, 1.55, 1.15, 1.25, and 1.60 cm(2) V(-1) s(-1), respectively. The detection limits were found to be 0.1 ng for RDX, 10 ng for TNT, 0.5 ng for PETN, 5.0 ng for HMX, and 10 ng for DNT. Simplified chromatograms were observed when nitrogen, as opposed to air, was used as the drift gas, but the detection limits were approximately 10 times worse (i.e., less sensitivity of detection).

  10. Utilization of deep eutectic solvents as novel mobile phase additives for improving the separation of bioactive quaternary alkaloids.

    PubMed

    Tan, Ting; Zhang, Mingliang; Wan, Yiqun; Qiu, Hongdeng

    2016-01-01

    Deep eutectic solvents (DESs) were used as novel mobile phase additives to improve chromatographic separation of four quaternary alkaloids including coptisine chloride, sanguinarine, berberine chloride and chelerythrine on a C18 column. DESs as a new class of ionic liquids are renewably sourced, environmentally benign, low cost and easy to prepare. Seven DESs were obtained by mixing different hydrogen acceptors and hydrogen-bond donors. The effects of organic solvents, the concentration of DESs, the types of DESs and the pH values of the buffer solution on the separation of the analytes were investigated. The composition of acetonitrile and 1.0% deep eutectic solvents aqueous solution (pH 3.3, adjusted with hydrochloric acid) in a 32:68 (v/v) ratio was used as optimized mobile phase, with which four quaternary alkaloids were well separated. When a small amount of DESs was added in the mobile phase for the separation of alkaloids on the C18 column, noticeable improvements were distinctly observed such as decreasing peak tailing and improving resolution. The separation mechanism mediated by DESs as mobile phase additives can be attributed to combined effect of both hydrogen acceptors and hydrogen-bond donors. For example, choline chloride can effectively cover the residual silanols on silica surface and ethylene glycol can reduce the retention time of analytes. The proposed method has been applied to determine BerbC in Lanqin Chinese herbal oral solution and BerbC tablet. Utilization of DESs in mobile phase can efficiently improve separation and selectivity of analytes from complex samples.

  11. Utilization of deep eutectic solvents as novel mobile phase additives for improving the separation of bioactive quaternary alkaloids.

    PubMed

    Tan, Ting; Zhang, Mingliang; Wan, Yiqun; Qiu, Hongdeng

    2016-03-01

    Deep eutectic solvents (DESs) were used as novel mobile phase additives to improve chromatographic separation of four quaternary alkaloids including coptisine chloride, sanguinarine, berberine chloride and chelerythrine on a C18 column. DESs as a new class of ionic liquids are renewably sourced, environmentally benign, low cost and easy to prepare. Seven DESs were obtained by mixing different hydrogen acceptors and hydrogen-bond donors. The effects of organic solvents, the concentration of DESs, the types of DESs and the pH values of the buffer solution on the separation of the analytes were investigated. The composition of acetonitrile and 1.0% deep eutectic solvents aqueous solution (pH 3.3, adjusted with hydrochloric acid) in a 32:68 (v/v) ratio was used as optimized mobile phase, with which four quaternary alkaloids were well separated. When a small amount of DESs was added in the mobile phase for the separation of alkaloids on the C18 column, noticeable improvements were distinctly observed such as decreasing peak tailing and improving resolution. The separation mechanism mediated by DESs as mobile phase additives can be attributed to combined effect of both hydrogen acceptors and hydrogen-bond donors. For example, choline chloride can effectively cover the residual silanols on silica surface and ethylene glycol can reduce the retention time of analytes. The proposed method has been applied to determine BerbC in Lanqin Chinese herbal oral solution and BerbC tablet. Utilization of DESs in mobile phase can efficiently improve separation and selectivity of analytes from complex samples. PMID:26717817

  12. Reactant ion chemistry for detection of TNT, RDX, and PETN using an ion mobility spectrometer

    SciTech Connect

    Klassen, S.E.; Rodacy, P.; Silva, R.

    1997-09-01

    This report describes the responses of three energetic materials (TNT, RDX, and PETN) to varying reactant ion chemistries and IMS cell temperatures. The following reactant ion chemistries were evaluated; air-dry; air-wet; methylene chloride-dry; methylene chloride-wet; methylene bromide-dry; nitrogen dioxide-wet; sulfur dioxide-wet. The temperature was varied between 160 - 220{degrees}C.

  13. Detection of cocaine and its metabolites in urine using solid phase extraction-ion mobility spectrometry with alternating least squares.

    PubMed

    Lu, Yao; O'Donnell, Ryan M; Harrington, Peter B

    2009-08-10

    A reliable, alternative screening method for detection of cocaine and its metabolites, benzoylecgonine and cocaethylene in urine is demonstrated using solid phase extraction (SPE) coupled with ion mobility spectrometry (IMS). Data analysis with alternating least squares (ALS) is used to model IMS spectral datasets and separate the reactant ion peak from the product ion peaks. IMS has been used as a screening device for drug and explosive detection for many years. It has the advantages of atmospheric pressure operation, simple sample preparation, portability, fast analysis, and high sensitivity when compared to similar methods. Coupling SPE with IMS decreases the detection limits of drug metabolites in urine while removing salts and other polar compounds that suppress ionization during the measurement. The IMS analysis time in this experiment is 20s, much shorter than traditional chromatographic analysis. The application of ALS further increases the sensitivity and selectivity of this method. The detection limits of benzoylecgonine and cocaethylene are 10 ng/mL and 4 ng/mL, respectively. Commercial adulteration of urine specimens does not influence the ability to detect cocaine metabolites after sampling the urine with SPE. This method provides forensic chemists a viable approach for fast and simple drug screening. PMID:19457629

  14. Fragmentation of molecular ions in differential mobility spectrometry as a method for identification of chemical warfare agents.

    PubMed

    Maziejuk, M; Puton, J; Szyposzyńska, M; Witkiewicz, Z

    2015-11-01

    The subject of the work is the use of differential mobility spectrometry (DMS) for the detection of chemical warfare agents (CWA). Studies were performed for mustard gas, i.e., bis(2-chloroethyl)sulfide (HD), sarin, i.e., O-isopropyl methylphosphonofluoridate (GB) and methyl salicylate (MS) used as test compounds. Measurements were conducted with two ceramic DMS analyzers of different constructions allowing the generation of an electric field with an intensity of more than 120 Td. Detector signals were measured for positive and negative modes of operation in a temperature range from 0 to 80 °C. Fragmentations of ions containing analyte molecules were observed for all tested compounds. The effective temperatures of fragmentation estimated on the basis of dispersion plots were equal from about 148 °C for GB to 178 °C for MS. It was found that values of separation voltage (SV) and compensation voltage (CV) at which the fragmentation of sample ions is observed may be the parameters improving the certainty of detection for different analytes. The DMS analyzers enabling the observation of ion fragmentation can be successfully used for effective CWA detection. PMID:26452948

  15. Fragmentation of molecular ions in differential mobility spectrometry as a method for identification of chemical warfare agents.

    PubMed

    Maziejuk, M; Puton, J; Szyposzyńska, M; Witkiewicz, Z

    2015-11-01

    The subject of the work is the use of differential mobility spectrometry (DMS) for the detection of chemical warfare agents (CWA). Studies were performed for mustard gas, i.e., bis(2-chloroethyl)sulfide (HD), sarin, i.e., O-isopropyl methylphosphonofluoridate (GB) and methyl salicylate (MS) used as test compounds. Measurements were conducted with two ceramic DMS analyzers of different constructions allowing the generation of an electric field with an intensity of more than 120 Td. Detector signals were measured for positive and negative modes of operation in a temperature range from 0 to 80 °C. Fragmentations of ions containing analyte molecules were observed for all tested compounds. The effective temperatures of fragmentation estimated on the basis of dispersion plots were equal from about 148 °C for GB to 178 °C for MS. It was found that values of separation voltage (SV) and compensation voltage (CV) at which the fragmentation of sample ions is observed may be the parameters improving the certainty of detection for different analytes. The DMS analyzers enabling the observation of ion fragmentation can be successfully used for effective CWA detection.

  16. Application Of Electronic Nose And Ion Mobility Spectrometer To Quality Control Of Spice Mixtures

    NASA Astrophysics Data System (ADS)

    Banach, U.; Tiebe, C.; Hübert, Th.

    2009-05-01

    The aim of the paper is to demonstrate the application of electronic nose (e-nose) and ion mobility spectrometry (IMS) to quality control and to find out product adulteration of spice mixtures. Therefore the gaseous head space phase of four different spice mixtures (spices for sausages and saveloy) was differed from original composition and product adulteration. In this set of experiments metal-oxide type e-nose (KAMINA-type) has been used, and characteristic patterns of data corresponding to various complex odors of the four different spice mixtures were generated. Simultaneously an ion mobility spectrometer was coupled also to an emission chamber for the detection of gaseous components of spice mixtures. The two main methods that have been used show a clear discrimination between the original spice mixtures and product adulteration could be distinguished from original spice mixtures.

  17. Application Of Electronic Nose And Ion Mobility Spectrometer To Quality Control Of Spice Mixtures

    SciTech Connect

    Banach, U.; Tiebe, C.; Huebert, Th.

    2009-05-23

    The aim of the paper is to demonstrate the application of electronic nose (e-nose) and ion mobility spectrometry (IMS) to quality control and to find out product adulteration of spice mixtures. Therefore the gaseous head space phase of four different spice mixtures (spices for sausages and saveloy) was differed from original composition and product adulteration. In this set of experiments metal-oxide type e-nose (KAMINA-type) has been used, and characteristic patterns of data corresponding to various complex odors of the four different spice mixtures were generated. Simultaneously an ion mobility spectrometer was coupled also to an emission chamber for the detection of gaseous components of spice mixtures. The two main methods that have been used show a clear discrimination between the original spice mixtures and product adulteration could be distinguished from original spice mixtures.

  18. A novel approach to increasing cocaine detection confidence utilizing ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Jadamec, J. Richard; Su, Chih-Wu; Rigdon, Stephen; Norwood, Lavan

    1995-01-01

    When a positive detection of a narcotic occurs during the search of a vessel, a decision has to be made whether further intensive search is warranted. In terms of unwarranted delays of vessels and possible property damage, the accuracy of the analytical determination is very important. Analytical accuracy becomes critical when the data may be used in court actions as evidence. For this purpose, the U.S. Coast Guard has been investigating several confirmatory ion mobility spectrometry (IMS) field methods for the detection and identification of cocaine. This paper presents the findings of our investigations on the use of catalytic pyrolysis and base hydrolysis as confirmatory methods. The catalytic effects of various metals on the pyrolysis reaction are reported. In addition, the effects of several different ion mobility spectrometer sample transfer mediums and varying laboratory conditions on the base hydrolysis of the cocaine molecule are also be reported.

  19. Lithium-ion battery electrolyte mobility at nano-confined graphene interfaces

    NASA Astrophysics Data System (ADS)

    Moeremans, Boaz; Cheng, Hsiu-Wei; Hu, Qingyun; Garces, Hector F.; Padture, Nitin P.; Renner, Frank Uwe; Valtiner, Markus

    2016-08-01

    Interfaces are essential in electrochemical processes, providing a critical nanoscopic design feature for composite electrodes used in Li-ion batteries. Understanding the structure, wetting and mobility at nano-confined interfaces is important for improving the efficiency and lifetime of electrochemical devices. Here we use a Surface Forces Apparatus to quantify the initial wetting of nanometre-confined graphene, gold and mica surfaces by Li-ion battery electrolytes. Our results indicate preferential wetting of confined graphene in comparison with gold or mica surfaces because of specific interactions of the electrolyte with the graphene surface. In addition, wetting of a confined pore proceeds via a profoundly different mechanism compared with wetting of a macroscopic surface. We further reveal the existence of molecularly layered structures of the confined electrolyte. Nanoscopic confinement of less than 4-5 nm and the presence of water decrease the mobility of the electrolyte. These results suggest a lower limit for the pore diameter in nanostructured electrodes.

  20. Electrical control of Co/Ni magnetism adjacent to gate oxides with low oxygen ion mobility

    SciTech Connect

    Yan, Y. N.; Zhou, X. J.; Li, F.; Cui, B.; Wang, Y. Y.; Wang, G. Y.; Pan, F.; Song, C.

    2015-09-21

    We investigate the electrical manipulation of Co/Ni magnetization through a combination of ionic liquid and oxide gating, where HfO{sub 2} with a low O{sup 2−} ion mobility is employed. A limited oxidation-reduction process at the metal/HfO{sub 2} interface can be induced by large electric field, which can greatly affect the saturated magnetization and Curie temperature of Co/Ni bilayer. Besides the oxidation/reduction process, first-principles calculations show that the variation of d electrons is also responsible for the magnetization variation. Our work discloses the role of gate oxides with a relatively low O{sup 2−} ion mobility in electrical control of magnetism, and might pave the way for the magneto-ionic memory with low power consumption and high endurance performance.

  1. Fundamental studies of gas phase ionic reactions by ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Giles, K.; Knighton, W. B.; Sahlstrom, K. E.; Grimsrud, E. P.

    1995-01-01

    Ion mobility spectrometry (IMS) provides a promising approach to the study of gas phase ionic reactions in buffer gases at unusually high pressures. This point is illustrated here by studies of the Sn2 nucleophilic displacement reaction, Cl(-) + CH3Br yields Br + CH3Br, using IMS at atmospheric pressure. The equilibrium clustering reaction, Cl(-)(CHCI3)(n - 1) + CHCI3 yields Cl(-)(CHCI3)(n), where n = 1 and 2, and the effect of clustering on the Sn2 reaction with CH3Br have also been characterized by this IMS-based kinetic method. Present problems and anticipated improvements in the application of ion mobility spectrometry to studies of other gas phase ionic processes are discussed.

  2. Resonance ionization laser ion sources for on-line isotope separators (invited).

    PubMed

    Marsh, B A

    2014-02-01

    A Resonance Ionization Laser Ion Source (RILIS) is today considered an essential component of the majority of Isotope Separator On Line (ISOL) facilities; there are seven laser ion sources currently operational at ISOL facilities worldwide and several more are under development. The ionization mechanism is a highly element selective multi-step resonance photo-absorption process that requires a specifically tailored laser configuration for each chemical element. For some isotopes, isomer selective ionization may even be achieved by exploiting the differences in hyperfine structures of an atomic transition for different nuclear spin states. For many radioactive ion beam experiments, laser resonance ionization is the only means of achieving an acceptable level of beam purity without compromising isotope yield. Furthermore, by performing element selection at the location of the ion source, the propagation of unwanted radioactivity downstream of the target assembly is reduced. Whilst advances in laser technology have improved the performance and reliability of laser ion sources and broadened the range of suitable commercially available laser systems, many recent developments have focused rather on the laser/atom interaction region in the quest for increased selectivity and/or improved spectral resolution. Much of the progress in this area has been achieved by decoupling the laser ionization from competing ionization processes through the use of a laser/atom interaction region that is physically separated from the target chamber. A new application of gas catcher laser ion source technology promises to expand the capabilities of projectile fragmentation facilities through the conversion of otherwise discarded reaction fragments into high-purity low-energy ion beams. A summary of recent RILIS developments and the current status of laser ion sources worldwide is presented. PMID:24593628

  3. Resonance ionization laser ion sources for on-line isotope separators (invited)

    SciTech Connect

    Marsh, B. A.

    2014-02-15

    A Resonance Ionization Laser Ion Source (RILIS) is today considered an essential component of the majority of Isotope Separator On Line (ISOL) facilities; there are seven laser ion sources currently operational at ISOL facilities worldwide and several more are under development. The ionization mechanism is a highly element selective multi-step resonance photo-absorption process that requires a specifically tailored laser configuration for each chemical element. For some isotopes, isomer selective ionization may even be achieved by exploiting the differences in hyperfine structures of an atomic transition for different nuclear spin states. For many radioactive ion beam experiments, laser resonance ionization is the only means of achieving an acceptable level of beam purity without compromising isotope yield. Furthermore, by performing element selection at the location of the ion source, the propagation of unwanted radioactivity downstream of the target assembly is reduced. Whilst advances in laser technology have improved the performance and reliability of laser ion sources and broadened the range of suitable commercially available laser systems, many recent developments have focused rather on the laser/atom interaction region in the quest for increased selectivity and/or improved spectral resolution. Much of the progress in this area has been achieved by decoupling the laser ionization from competing ionization processes through the use of a laser/atom interaction region that is physically separated from the target chamber. A new application of gas catcher laser ion source technology promises to expand the capabilities of projectile fragmentation facilities through the conversion of otherwise discarded reaction fragments into high-purity low-energy ion beams. A summary of recent RILIS developments and the current status of laser ion sources worldwide is presented.

  4. Resonance ionization laser ion sources for on-line isotope separators (invited).

    PubMed

    Marsh, B A

    2014-02-01

    A Resonance Ionization Laser Ion Source (RILIS) is today considered an essential component of the majority of Isotope Separator On Line (ISOL) facilities; there are seven laser ion sources currently operational at ISOL facilities worldwide and several more are under development. The ionization mechanism is a highly element selective multi-step resonance photo-absorption process that requires a specifically tailored laser configuration for each chemical element. For some isotopes, isomer selective ionization may even be achieved by exploiting the differences in hyperfine structures of an atomic transition for different nuclear spin states. For many radioactive ion beam experiments, laser resonance ionization is the only means of achieving an acceptable level of beam purity without compromising isotope yield. Furthermore, by performing element selection at the location of the ion source, the propagation of unwanted radioactivity downstream of the target assembly is reduced. Whilst advances in laser technology have improved the performance and reliability of laser ion sources and broadened the range of suitable commercially available laser systems, many recent developments have focused rather on the laser/atom interaction region in the quest for increased selectivity and/or improved spectral resolution. Much of the progress in this area has been achieved by decoupling the laser ionization from competing ionization processes through the use of a laser/atom interaction region that is physically separated from the target chamber. A new application of gas catcher laser ion source technology promises to expand the capabilities of projectile fragmentation facilities through the conversion of otherwise discarded reaction fragments into high-purity low-energy ion beams. A summary of recent RILIS developments and the current status of laser ion sources worldwide is presented.

  5. Swelling and softening of lithium-ion battery separators in electrolyte solvents

    NASA Astrophysics Data System (ADS)

    Gor, Gennady Y.; Cannarella, John; Leng, Collen Z.; Vishnyakov, Aleksey; Arnold, Craig B.

    2015-10-01

    The mechanical stability of inactive polymeric components (e.g. separator and binder) can play an important role in the long term performance of lithium-ion batteries. Here we investigate the effects of electrolyte solvents on the mechanical properties of a polypropylene battery separator through experimental measurements of thickness and elastic modulus of separator samples immersed in different solvent environments. We find that certain electrolyte solvents such as dimethyl carbonate, diethyl carbonate, and ethyl acetate cause noticeable softening of the separator. However, in other solvent environments such as propylene carbonate and acetonitrile, the separator retains the mechanical properties of a dry material. We show that the mechanical property reduction can be attributed to polymer swelling and explain these observations in the context of the Hildebrand solubility and Flory-Huggins interaction parameters. The solubility/interaction parameter analysis provides a straightforward method for predicting the in situ mechanical behavior of polymer separators in solvent environments. The relationships discussed herein can be used to screen and identify mechanically-stable polymer and electrolyte solvent pairs for use in lithium-ion batteries designed for long life.

  6. Ion mobility spectrometry: Arriving on site and moving beyond a low profile

    SciTech Connect

    Baumbach, Joerg Ingo; Eiceman, Gary A.

    1999-09-01

    Since the inception of modern analytical ion mobility spectrometry in the early 1970s, developments in IMS have followed an unconventional pattern. During the 1990s, dramatic changes have occurred in the understanding of response, so that contemporary IMS is largely unrecognizable from any descriptions in the 1970s and 1980s. Some of these changes are documented in this article and the future of IMS is outlined. (c) American Institute of Physics (c) 2000 American Institute of Physics.

  7. Preorganized and immobilized ligands for metal ion separations. Final report, June, 1994--May, 1997

    SciTech Connect

    Paine, R.T.

    1997-12-01

    Historically, much of the interest shown in f-element ion coordination chemistry has been driven by practical needs to devise separation schemes for lanthanide (Ln) and actinide (An) ions. However, few of the separations are completely satisfactory, and the basic chemical framework needed to achieve improvements is still poorly developed. As a result, studies of the fundamental aspects of f-element coordination chemistry are still pertinent not only to the evolution of improved separations, but also waste remediation, biological and medical applications of Ln ions, biochemistry of An ion decorporation, and new solid state materials preparations. The research objectives during the present grant period were to (1) synthesize new bifunctional and trifunctional chelating ligands, particularly in the class of new phosphonopyridine N-oxides; (2) characterize the structural features of the Ln and An coordination complexes formed by these ligands; (3) determine the extraction efficacy of these ligands; and (4) explore synthetic approaches for formation of dendritic polymers containing phosphoryl terminating groups. Some highlights of recently accomplished work and still-in-progress research are outlined.

  8. Detection of Volatile Vapors Emitted from Explosives with a Hand-held Ion Mobility Spectrometer

    SciTech Connect

    Ewing, Robert Gordon; Miller, Carla Jean

    2001-11-01

    Vapor detection of plastic explosives is difficult because of the low vapor pressures of explosive components (i.e. RDX and PETN) present in the complex elastomeric matrix. To facilitate vapor detection of plastic explosives, detection agents (taggants) with higher vapor pressures can be added to bulk explosives during manufacture. This paper investigates the detection of two of these taggants, ethyleneglycol dinitrate (EGDN) and 2,3-dimethyl-2,3-dinitrobutane (DMNB), using a handheld ion mobility spectrometer. These two taggants were detected both from neat vapor sources as well as from bulk explosives (nitroglycerin (NG)-dynamite and C-4 tagged with DMNB). EGDN was detected from NG-dynamite as EGDN·NO3- at a reduced mobility value of 1.45 cm2 V-1 s-1 with detection limits estimated to be about 10 ppbv. DMNB was identified from tagged C-4 as both negative and positive ions with reduced mobility values of 1.33 cm2 V-1 s-1 for DMNB·NO2- and 1.44 cm2 V-1s-1 for DMNB·NH4+. Positive ions for cyclohexanone were also apparent in the spectra from tagged C-4 producing three additional peaks.

  9. A compact high-resolution X-ray ion mobility spectrometer.

    PubMed

    Reinecke, T; Kirk, A T; Heptner, A; Niebuhr, D; Böttger, S; Zimmermann, S

    2016-05-01

    For the ionization of gaseous samples, most ion mobility spectrometers employ radioactive ionization sources, e.g., containing (63)Ni or (3)H. Besides legal restrictions, radioactive materials have the disadvantage of a constant radiation with predetermined intensity. In this work, we replaced the (3)H source of our previously described high-resolution ion mobility spectrometer with 75 mm drift tube length with a commercially available X-ray source. It is shown that the current configuration maintains the resolving power of R = 100 which was reported for the original setup containing a (3)H source. The main advantage of an X-ray source is that the intensity of the radiation can be adjusted by varying its operating parameters, i.e., filament current and acceleration voltage. At the expense of reduced resolving power, the sensitivity of the setup can be increased by increasing the activity of the source. Therefore, the performance of the setup can be adjusted to the specific requirements of any application. To investigate the relation between operating parameters of the X-Ray source and the performance of the ion mobility spectrometer, parametric studies of filament current and acceleration voltage are performed and the influence on resolving power, peak height, and noise is analyzed.

  10. Ion mobility spectrometer, spectrometer analyte detection and identification verification system, and method

    DOEpatents

    Atkinson, David A.

    2002-01-01

    Methods and apparatus for ion mobility spectrometry and analyte detection and identification verification system are disclosed. The apparatus is configured to be used in an ion mobility spectrometer and includes a plurality of reactant reservoirs configured to contain a plurality of reactants which can be reacted with the sample to form adducts having varying ion mobilities. A carrier fluid, such as air or nitrogen, is used to carry the sample into the spectrometer. The plurality of reactants are configured to be selectively added to the carrier stream by use inlet and outlet manifolds in communication with the reagent reservoirs, the reservoirs being selectively isolatable by valves. The invention further includes a spectrometer having the reagent system described. In the method, a first reactant is used with the sample. Following a positive result, a second reactant is used to determine whether a predicted response occurs. The occurrence of the second predicted response tends to verify the existence of a component of interest within the sample. A third reactant can also be used to provide further verification of the existence of a component of interest. A library can be established of known responses of compounds of interest with various reactants and the results of a specific multi-reactant survey of a sample can be compared against the library to determine whether a component detected in the sample is likely to be a specific component of interest.

  11. Qualitative screening for adulterants in weight-loss supplements by ion mobility spectrometry.

    PubMed

    Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Mans, Daniel J; Mecker-Pogue, Laura C; Kauffman, John F; Westenberger, Benjamin J; Buhse, Lucinda F

    2012-12-01

    Ion mobility spectrometry (IMS) served as a rapid, qualitative screening tool for the analysis of adulterated weight-loss products. We have previously shown that sibutramine extracted into methanol from dietary supplements can be detected at low levels (2ng) using a portable IMS spectrometer, and have adapted a similar method for the analysis of additional weight-loss product adulterants. An FDA collaborative study helped to define the limits for fluoxetine with a limit of detection of 2ng. We also evaluated more readily available, less toxic extraction solvents and found isopropanol and water were comparable to methanol. Isopropanol was favored over water for two reasons: (1) water increases the analysis time and (2) aqueous solutions were more susceptible to pH change, which affected the detection of sibutramine. In addition to sibutamine and fluoxetine, we surveyed 11 weight-loss adulterants; bumetanide, fenfluramine, furosemide, orlistat, phenolphthalein, phentermine, phenytoin, rimonabant, sertraline and two sibutramine analogs, desmethylsibutramine and didesmethylsibutramine, using portable and benchtop ion mobility spectrometers. Out of these 13 active pharmaceutical ingredients (APIs), portable and benchtop ion mobility spectrometers were capable of screening products for 10 of these APIs. The developed procedure was applied to two weight-loss dietary supplements using both portable and benchtop instruments. One product contained didesmethylsibutramine while the other contained didesmethylsibutramine and phenolphthalein. PMID:22902504

  12. Carbon dots rooted agarose hydrogel hybrid platform for optical detection and separation of heavy metal ions.

    PubMed

    Gogoi, Neelam; Barooah, Mayuri; Majumdar, Gitanjali; Chowdhury, Devasish

    2015-02-11

    A robust solid sensing platform for an on-site operational and accurate detection of heavy metal is still a challenge. We introduce chitosan based carbon dots rooted agarose hydrogel film as a hybrid solid sensing platform for detection of heavy metal ions. The fabrication of the solid sensing platform is centered on simple electrostatic interaction between the NH3+ group present in the carbon dots and the OH- groups present in agarose. Simply on dipping the hydrogel film strip into the heavy metal ion solution, in particular Cr6+, Cu2+, Fe3+, Pb2+, Mn2+, the strip displays a color change, viz., Cr6+→yellow, Cu2+→blue, Fe3+→brown, Pb2+→white, Mn2+→tan brown. The optical detection limit of the respective metal ion is found to be 1 pM for Cr6+, 0.5 μM for Cu2+, and 0.5 nM for Fe3+, Pb2+, and Mn2+ by studying the changes in UV-visible reflectance spectrum of the hydrogel film. Moreover, the hydrogel film finds applicability as an efficient filtration membrane for separation of these quintet heavy metal ions. The strategic fundamental feature of this sensing platform is the successful capability of chitosan to form colored chelates with transition metals. This proficient hybrid hydrogel solid sensing platform is thus the most suitable to employ as an on-site operational, portable, cheap colorimetric-optical detector of heavy metal ion with potential skill in their separation. Details of the possible mechanistic insight into the colorimetric detection and ion separation are also discussed.

  13. High-resolution mobility analysis of charge-reduced electrosprayed protein ions.

    PubMed

    Fernandez de la Mora, Juan

    2015-04-01

    Many mobility studies (IMS) of electrospray ions with charge states z reduced to unity have shown a singular ability to analyze large protein complexes and viruses, though with wide mobility peaks (fwhm ∼ 20%). Here we confirm that this limitation arises primarily when early charge reduction precedes drop evaporation (suppressing secondary atomization by the usual sequence of many Coulomb explosions). By drying before neutralizing, we achieve a protein fwhm of ∼3.7%. A positively biased electrospraying capillary is coaxial with a cylindrical charge-reduction (CR) chamber coated with radioactive Ni-63 (10 mCi) that fills the CR chamber with a bipolar ionic atmosphere. A screen interposed between the spraying capillary and the CR chamber limits penetration of the neutralizing anions into the electrospray (ES) chamber, precluding destabilization of the ES tip, even when brought very close to the grid to enhance ion transmission. As ES cations cross the grid, driven by their own space charge, they recombine with CR ions reducing their charge state as well as space charge dispersion. The setup is tested with the protein ovalbumin (MW ∼ 44.3 kDa) and its clusters up to the tetramer, by analyzing the charge-reduced ions with a differential mobility analyzer (DMA). At gas sample flow rates of ∼1 L/min, the dominant peaks are singly charged (z = 1). They are widened by clustering of involatile solution impurities, depending on spray quality and solution cleanness, with fwhm as small as 3.7% achieved in desalted and acidified solutions. When using sharp nanospray capillaries, the grid may be removed, resulting in ∼2-fold increased ion transmission. In the absence of the grid, however, spray stability and quality are often compromised, even with capillary tip diameters as small as 30 μm. PMID:25803189

  14. Studies on stannic selenoarsenate. II. Separation of uranium from numerous metal ions

    SciTech Connect

    Nabi, S.A.; Siddiqi, Z.M.; Rao, R.A.K.

    1982-12-01

    Stannic selenoarsenate has been synthesized by adding 0.05 M sodium selenite and 0.05 M sodium arsenate to a 0.05 M solution of stannic chloride in a volume ratio of 1:1:1 at pH 1. A tentative structure has been proposed on the basis of chemical composition, pH titrations, and infrared and thermogravimetric analyses. Distribution coefficients of several metal ions have been studied in hydrochloric acid, citric acid, ammonium citrate-citric acid, and water-dioxane systems. The unusual adsorption behavior or uranium has been utilized for its quantitative separation from several metal ions.

  15. Laser desorption-ion mobility spectrometry as a useful tool for imaging of thin layer chromatography surface.

    PubMed

    Ilbeigi, Vahideh; Sabo, Martin; Valadbeigi, Younes; Matejcik, Stefan; Tabrizchi, Mahmoud

    2016-08-12

    We present a novel method for coupling thin layer chromatography (TLC) with ion mobility spectrometry (IMS) using laser desorption technique (LD). After separation of the compounds by TLC, the TLC surface was sampled by the LD-IMS without any further manipulation or preparation. The position of the laser was fixed and the TLC plate was moved in desired directions by the motorized micro-positioning stage. The method was successfully applied to analyze the TLC plates containing explosives (tri nitro toluene, 1,3,5-trinitro- 1,3,5-triazacyclohexane, pentaerythritol tetranitrate, 2,4-dinitro toluene and 3,4-dinitro toluene), amino acids (alanine, proline and isoleucine), nicotine and diphenylamine mixtures and detection limits for these compounds were determined. Combination of TLC with LD-IMS technique offers additional separation dimension, allowing separation of overlapping TLC analytes. The time for TLC sampling by LD-IMS was less than 80s. The scan rate for LD is adjustable so that fast and effective analysis of the mixtures is possible with the proposed method. PMID:27397925

  16. Structural analysis of ruthenium-arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT.

    PubMed

    Czerwinska, Izabella; Far, Johann; Kune, Christopher; Larriba-Andaluz, Carlos; Delaude, Lionel; De Pauw, Edwin

    2016-04-21

    Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (), [RuCl2(p-cymene)(PPh3)] (), and [RuCl2(p-cymene)(PTA)] () in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes and led to the corresponding [RuCl(p-cymene)(PR3)](+) ions via the dissociation of a chlorido ligand, whereas RAPTA-C () afforded two molecular ions by in-source oxidation ([Ru(III)Cl2(p-cymene)(PTA)](+)) or protonation ([RuCl2(p-cymene)(PTA+H)](+)). Control experiments showed that the balance between these two ionization paths was strongly influenced by the nature of the solvent used for infusion. Collision cross sections (CCSs) of the four molecular ions accurately reflected the variations of steric bulk inferred from the Tolman steric parameters (θ) of the phosphine ligands. Moreover, DFT calculations combined with a model based on the kinetic theory of gases (the trajectory method of the IMoS software) afforded reliable CCS predictions. The almost two times higher dipole moment of [RuCl2(p-cymene)(PTA+H)](+) (μ = 13.75 D) compared to [Ru(III)Cl2(p-cymene)(PTA)](+) (μ = 7.18 D) was held responsible for increased ion-induced dipole interactions with a polarizable drift gas such as N2. Further experiments with He and CO2 confirmed that increasing the polarizability of the buffer gas improved the separation between the two molecular ions derived from complex . The fragmentation patterns of complexes were determined by CID. The sequence of collision voltages at which 50% of a precursor ion dissociates (V50) recorded for the molecular ions derived from compounds was in good agreement with simple electronic considerations based on the donor strength of the phosphine ligand. Thus, the CCS and V50 parameters used to determine the shape and stability of ionic species in the gas phase are complementary

  17. Structural analysis of ruthenium-arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT.

    PubMed

    Czerwinska, Izabella; Far, Johann; Kune, Christopher; Larriba-Andaluz, Carlos; Delaude, Lionel; De Pauw, Edwin

    2016-04-21

    Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (), [RuCl2(p-cymene)(PPh3)] (), and [RuCl2(p-cymene)(PTA)] () in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes and led to the corresponding [RuCl(p-cymene)(PR3)](+) ions via the dissociation of a chlorido ligand, whereas RAPTA-C () afforded two molecular ions by in-source oxidation ([Ru(III)Cl2(p-cymene)(PTA)](+)) or protonation ([RuCl2(p-cymene)(PTA+H)](+)). Control experiments showed that the balance between these two ionization paths was strongly influenced by the nature of the solvent used for infusion. Collision cross sections (CCSs) of the four molecular ions accurately reflected the variations of steric bulk inferred from the Tolman steric parameters (θ) of the phosphine ligands. Moreover, DFT calculations combined with a model based on the kinetic theory of gases (the trajectory method of the IMoS software) afforded reliable CCS predictions. The almost two times higher dipole moment of [RuCl2(p-cymene)(PTA+H)](+) (μ = 13.75 D) compared to [Ru(III)Cl2(p-cymene)(PTA)](+) (μ = 7.18 D) was held responsible for increased ion-induced dipole interactions with a polarizable drift gas such as N2. Further experiments with He and CO2 confirmed that increasing the polarizability of the buffer gas improved the separation between the two molecular ions derived from complex . The fragmentation patterns of complexes were determined by CID. The sequence of collision voltages at which 50% of a precursor ion dissociates (V50) recorded for the molecular ions derived from compounds was in good agreement with simple electronic considerations based on the donor strength of the phosphine ligand. Thus, the CCS and V50 parameters used to determine the shape and stability of ionic species in the gas phase are complementary

  18. Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange

    SciTech Connect

    Hobbs, D. T.; Shehee, T. C.; Clearfield, A.

    2013-09-17

    This project seeks to determine if inorganic or hybrid inorganic ion-exchange materials can be exploited to provide effective americium and curium separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of the tested ion-exchange materials for actinide and lanthanide ions. During FY13, experimental work focused in the following areas: (1) investigating methods to oxidize americium in dilute nitric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium and (2) synthesis, characterization and testing of ion-exchange materials. Ion-exchange materials tested included alkali titanates, alkali titanosilicates, carbon nanotubes and group(IV) metal phosphonates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of Am(III). Experimental findings indicated that Pu(IV) is oxidized to Pu(VI) by peroxydisulfate, but there are no indications that the presence of plutonium affects the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used. Tests also explored the influence of nitrite on the oxidation of Am(III). Given the formation of Am(V) and Am(VI) in the presence of nitrite, it appears that nitrite is not a strong deterrent to the oxidation of Am(III), but may be limiting Am(VI) by quickly reducing Am(VI) to Am(V). Interestingly, additional absorbance peaks were observed in the UV-Vis spectra at 524 and 544 nm in both nitric acid and perchloric acid solutions when the peroxydisulfate was added as a solution. These peaks have not been previously observed and do not correspond to the expected peak locations for oxidized americium in solution. Additional studies are in progress to identify these unknown peaks. Three titanosilicate ion exchangers were synthesized using a microwave-accelerated reaction system (MARS) and determined to have high affinities

  19. Ion Mobility Mass Spectrometry for Extracting Spectra of N-Glycans Directly from Incubation Mixtures Following Glycan Release: Application to Glycans from Engineered Glycoforms of Intact, Folded HIV gp120

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Sobott, Frank; Crispin, Max; Wrobel, Antoni; Bonomelli, Camille; Vasiljevic, Snezana; Scanlan, Christopher N.; Scarff, Charlotte A.; Thalassinos, Konstantinos; Scrivens, James H.

    2011-03-01

    The analysis of glycosylation from native biological sources is often frustrated by the low abundances of available material. Here, ion mobility combined with electrospray ionization mass spectrometry have been used to extract the spectra of N-glycans released with PNGase F from a serial titration of recombinantly expressed envelope glycoprotein, gp120, from the human immunodeficiency virus (HIV). Analysis was also performed on gp120 expressed in the α-mannosidase inhibitor, and in a matched mammalian cell line deficient in GlcNAc transferase I. Without ion mobility separation, ESI spectra frequently contained no observable ions from the glycans whereas ions from other compounds such as detergents and residual buffer salts were abundant. After ion mobility separation on a Waters T-wave ion mobility mass spectrometer, the N-glycans fell into a unique region of the ion mobility/ m/z plot allowing their profiles to be extracted with good signal:noise ratios. This method allowed N-glycan profiles to be extracted from crude incubation mixtures with no clean-up even in the presence of surfactants such as NP40. Furthermore, this technique allowed clear profiles to be obtained from sub-microgram amounts of glycoprotein. Glycan profiles were similar to those generated by MALDI-TOF MS although they were more susceptible to double charging and fragmentation. Structural analysis could be accomplished by MS/MS experiments in either positive or negative ion mode but negative ion mode gave the most informative spectra and provided a reliable approach to the analysis of glycans from small amounts of glycoprotein.

  20. Selective separation of sodium ions from a mixture with phenylalanine by Donnan dialysis with a profiled sulfogroup cation exchange membrane

    NASA Astrophysics Data System (ADS)

    Vasil'eva, V. I.; Goleva, E. A.

    2013-11-01

    The possibility of separating ions of metal from a mixture with ampholyte (an amino acid) by Donnan dialysis with an MK-40 sulfogroup cation exchange membrane is demonstrated. Conditions ensuring the selectivity and intensity of the mass transfer of sodium ions from a mixture with bipolar phenylalanine ions into a diffusate containing hydrochloric acid through a cation exchange membrane are found.

  1. Mobilities and longitudinal diffusion coefficients for Li + ions in Ar, Kr, and Xe at room temperature

    NASA Astrophysics Data System (ADS)

    Takebe, M.; Satoh, Y.; Iinuma, K.; Seto, K.

    1982-03-01

    The mobility of Li+ ions has been measured in Ar, Kr, and Xe at room temperature over the E/N range 6-218 Td in Ar, 8-216 Td in Kr, and 8-228 Td in Xe using a drift tube without mass spectrometer. The pressures used were 0.3-2.0 Torr for argon and 0.5-2.0 Torr for krypton and xenon. It is found that mobilities can be deduced from arrival time spectra which have been affected by reactions. The zero-field reduced mobilities are found to be 4.56±0.05 cm2/V s for Ar, 3.65±0.04 cm2/V s for Kr, and 2.77±0.03 cm2/V s for Xe. These mobility values are higher than the Langevin values by 2.3%, 4.9%, and 3.4%, respectively. The longitudinal diffusion coefficients were also measured and compared with values calculated using the generalized Einstein relations and the present mobility data. The experimental values are somewhat higher than the calculations in all cases.

  2. Application of a nonradioactive pulsed electron source for ion mobility spectrometry.

    PubMed

    Gunzer, Frank; Zimmermann, Stefan; Baether, Wolfgang

    2010-05-01

    Ion mobility spectrometry (IMS) is a well-known method for detecting hazardous compounds in air. Typical applications are the detection of chemical warfare agents, highly toxic industrial compounds, explosives, and drugs of abuse. Detection limits in the low part per billion range, fast response times, and simple instrumentation make this technique more and more popular. Common ion mobility spectrometers work by employing a radioactive source to provide electrons with high energy to ionize analytes in a series of chemical reactions. General security as well as regulatory concerns related to radioactivity result in the need for a different ionization source which on the other hand produces ions in a similar manner as a radioactive source since the ion chemistry is well-known. Here we show the application of a novel nonradioactive source that produces spectra similar to those obtained with radioactive tritium sources. Using this source in a pulsed mode offers the additional advantage of selecting certain analytes by their recombination time and thus significantly increasing the selectivity. The successful isolation of a target signal in the presence of contaminants using a pulsed electron beam or more precisely the difference in recombination times will be demonstrated for the case of dimethyl-methylphosphonate (DMMP) showing the potential of this source to reduce the possibility for false-positive detection of corresponding chemical warfare agents (CWA) by IMS. PMID:20353158

  3. Application of a nonradioactive pulsed electron source for ion mobility spectrometry.

    PubMed

    Gunzer, Frank; Zimmermann, Stefan; Baether, Wolfgang

    2010-05-01

    Ion mobility spectrometry (IMS) is a well-known method for detecting hazardous compounds in air. Typical applications are the detection of chemical warfare agents, highly toxic industrial compounds, explosives, and drugs of abuse. Detection limits in the low part per billion range, fast response times, and simple instrumentation make this technique more and more popular. Common ion mobility spectrometers work by employing a radioactive source to provide electrons with high energy to ionize analytes in a series of chemical reactions. General security as well as regulatory concerns related to radioactivity result in the need for a different ionization source which on the other hand produces ions in a similar manner as a radioactive source since the ion chemistry is well-known. Here we show the application of a novel nonradioactive source that produces spectra similar to those obtained with radioactive tritium sources. Using this source in a pulsed mode offers the additional advantage of selecting certain analytes by their recombination time and thus significantly increasing the selectivity. The successful isolation of a target signal in the presence of contaminants using a pulsed electron beam or more precisely the difference in recombination times will be demonstrated for the case of dimethyl-methylphosphonate (DMMP) showing the potential of this source to reduce the possibility for false-positive detection of corresponding chemical warfare agents (CWA) by IMS.

  4. An effective strategy to increase hydroxide-ion conductivity through microphase separation induced by hydrophobic-side chains

    NASA Astrophysics Data System (ADS)

    Zeng, L.; Zhao, T. S.

    2016-01-01

    A highly conductive and durable anion exchange membrane (AEM) is an essential component for alkaline electrochemical conversion and storage systems. Contrary to the conventional wisdom that the ionic conductivity can be improved by increasing the ion exchange capacity (IEC) through a cross-linking process, in this work, a new approach to improve the ionic conductivity by enhancing the ionic mobility is adopted. The microstructure of quaternary ammonia poly (2, 6-dimethyl-1, 4-phenylene oxide) (QAPPO) is manipulated through grafting with hydrophobic side chains, which will drive the well-established hydrophilic/hydrophobic domains and nano-phase separated, well-connected ionic channels. As a result, the local hydroxide concentration is enhanced by the novel microstructure, thereby improving the ionic conductivity of the as-prepared ionomers. The as-prepared ionomers, denoted as self-aggregated QAPPO-CF, with an intermediate IEC value achieved an ionic conductivity of 65 mS cm-1 at 80 °C, outperforming the QAPPO with an even higher IEC value. This result suggests that the microphase separation is an effective approach to enhance the ionic conductivity.

  5. Characterization of Polylactides with Different Stereoregularity Using Electrospray Ionization Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Kim, Kihyun; Lee, Jong Wha; Chang, Taihyun; Kim, Hugh I.

    2014-10-01

    We investigated the effect of stereoregularity on the gas-phase conformations of linear and cyclic polylactides (PLA) using electrospray ionization ion mobility mass spectrometry (ESI-IM-MS) combined with molecular dynamics simulations. IM-MS analysis of PLA ions shows intriguing difference between the collision cross section (ΩD) value of poly-L-lactide (PLLA) and poly-LD-lactide (PLDLA) ions with respect to their chain architecture and stereoregularity. In the singly sodiated linear PLA ( l-PLA•Na+) case, both l-PLLA and l-PLDLA up to 11mer have very similar ΩD values, but the ΩD values of l-PLLA are greater than that of l-PLDLA ions for larger ions. In the case of cyclic PLA ( c-PLA), c-PLLA•Na+ is more compact than c-PLDLA•Na+ for short PLA ions. However, c-PLLA exhibits larger ΩD value than c-PLDLA for PLA ions longer than 13mer. The origin of difference in the ΩD values was investigated using theoretical investigation of PLAs in the gas phase. The gas-phase conformation of PLA ions is influenced by Na+-oxygen coordination and the weak intramolecular hydrogen bond interaction, which are more effectively formed in more flexible chains. Therefore, the less flexible PLLA has a larger ΩD value than PLDLA. However, for short c-PLA, concomitant maximization of both Na+-oxygen coordination and hydrogen bond interaction is difficult due to the constricted chain freedom, which makes the ΩD value of PLAs in this range show a different trend compared with other PLA ions. Our study facilitates the understanding of correlation between stereoregularity of PLAs and their structure, providing potential utility of IM-MS to characterize stereoisomers of polymers.

  6. Simultaneous separation of nine metal ions and ammonium with nonaqueous capillary electrophoresis.

    PubMed

    Qu, Feng; Lin, Jin-Ming; Chen, Zuliang

    2004-01-01

    A simple and fast method for simultaneous separation of nine metal cations Ni2+, Cu2+, Co2+, Zn2+ Cd2+, K+, Na+, Mg2+ and Ca2+, and NH4+ in methanol is reported. The optimization for separation these 10 cations was achieved by using 0.5% acetic acid and 10 mM imidazole as electrolyte. The effects of water and ionic strength in the sample are discussed. The sensitive detection of transition metal ions was accomplished at 191 nm. The optimized method demonstrated high efficiency and good reproducibility, and was applied successfully to the qualitative and quantitative determination of transition metal ions in water samples, chemical reagents, oral zinc gluconate solution and human plasma. PMID:14753790

  7. Development of a short pulsed corona discharge ionization source for ion mobility spectrometry

    SciTech Connect

    An Yuan; Aliaga-Rossel, R.; Choi, Peter; Gilles, Jean-Paul

    2005-08-15

    The development of a pulsed corona discharge ionization source and its use in ion mobility spectrometry (IMS) is presented. In a point-plane electrode geometry, an electrical pulse up to 12 kV, 150 ns rise time and 500 ns pulse width was used to generate a corona discharge in air. A single positive high voltage pulse was able to generate about 1.6x10{sup 10} ions at energy consumption of 22 {mu}J. Since the temporal distribution of ions is in a pulsed form, the possibility of removal the ion gate has been investigated. By purposely arranging the interface between discharge field and drift field, nearly 10{sup 7} positive ions were drawn into the drift region with absence of the ion gate after every single discharge. The positive spectrum of acetone dimer (working at room temperature) was obtained with a resolving power of 20 by using this configuration. The advantages of this new scheme are the low power consumption compared with the dc method as well as the simplicity of the IMS cell structure.

  8. A gated atmospheric pressure drift tube ion mobility spectrometer-time-of-flight mass spectrometer.

    PubMed

    Heptner, Andre; Reinecke, Tobias; Langejuergen, Jens; Zimmermann, Stefan

    2014-08-22

    Identifying the compounds of an unknown gas mixture by using an ion mobility spectrometer (IMS) is a difficult task, because several ion species can be generated in the ionization process. One method to analyze the occurring peaks in an IMS spectrum is coupling an IMS to a mass spectrometer (MS). In our setup we coupled a (3)H drift tube IMS to a Bruker micrOTOF II. Therefore, the detector plate of the IMS is pierced and a transfer capillary is inserted. The ions are transferred via gas flow and electric fields into the MS. The transmission of the ions through the transfer capillary can be shuttered very precisely by increasing the electric potential of the detector generating a repulsive electric field. Thus, it is possible to transfer single ion clouds of generated IMS spectra into the mass spectrometer where a corresponding mass spectrum is generated. In this work we analyze the positive and negative IMS spectra of single analytes as well as gas mixtures and characterize the occurring ion species. PMID:25015244

  9. A gated atmospheric pressure drift tube ion mobility spectrometer-time-of-flight mass spectrometer.

    PubMed

    Heptner, Andre; Reinecke, Tobias; Langejuergen, Jens; Zimmermann, Stefan

    2014-08-22

    Identifying the compounds of an unknown gas mixture by using an ion mobility spectrometer (IMS) is a difficult task, because several ion species can be generated in the ionization process. One method to analyze the occurring peaks in an IMS spectrum is coupling an IMS to a mass spectrometer (MS). In our setup we coupled a (3)H drift tube IMS to a Bruker micrOTOF II. Therefore, the detector plate of the IMS is pierced and a transfer capillary is inserted. The ions are transferred via gas flow and electric fields into the MS. The transmission of the ions through the transfer capillary can be shuttered very precisely by increasing the electric potential of the detector generating a repulsive electric field. Thus, it is possible to transfer single ion clouds of generated IMS spectra into the mass spectrometer where a corresponding mass spectrum is generated. In this work we analyze the positive and negative IMS spectra of single analytes as well as gas mixtures and characterize the occurring ion species.

  10. Modeling ion exchange in glass with concentration-dependent diffusion coefficients and mobilities

    NASA Astrophysics Data System (ADS)

    Lupascu, Alexandru I.; Kevorkian, Antoine P.; Boudet, Thierry; Saint-Andre, Francoise; Persegol, Dominique; Levy, Michel

    1996-06-01

    Multimode buried waveguides made in silicate glass by field-assisted ion exchange present very asymmetric profiles. We show how this phenomenon originates in the large dependence of the kinetics on the local ion concentrations. For this purpose, we derive an interdiffusion equation that includes the effects of concentration-dependent diffusion coefficients and mobilities. We show how to deduce this dependence from measurements on ion- diffused samples. The maximum concentration of the incoming ions is computed from surface equilibrium conditions and is used in the interdiffusion equation as a limiting parameter for coefficient variations. To control the model accuracy for surface as well as buried waveguides, we measure ion profiles with three independent methods: M-lines, scanning electron microscopy, and near-field refractometry. When applied to Ag+-Na+ exchange in silicate glass, the model yields theoretical estimations in good agreement with experiments. This approach underlines the fundamentally nonlinear process that takes place during ion exchange and is also valuable to properly model singlemode waveguide fabrication.

  11. Surface modification of polypropylene separators in lithium-ion batteries using inductively coupled plasma treatment.

    PubMed

    Son, Jinyoung; Kim, Min-Sik; Lee, Hyun Woo; Yu, Jong-Sung; Kwon, Kwang-Ho

    2014-12-01

    We describe herein an improvement in the surface wettability of plasma-treated separators for use in lithium-ion batteries. We treated the separators with an O2/Ar inductively coupled plasma to increase their surface energy. The plasma treatment on the separator and plasma diagnostic experiments were performed in an inductively coupled plasma (ICP) reactor. The fraction of Ar in the O2/Ar plasma was changed from 0% to 100%. The plasma diagnostics were performed using optical emission spectroscopy and a double Langmuir probe. To confirm the morphological change of the separator membrane by the plasma treatment, we used the scanning electron microscopy. The surface energy measurements were performed using the drop method. We found that the plasma treatment transformed the separator from a hydrophobic membrane to a hydrophilic one, thereby achieving high separator wettability. After the treatment of the separators with O2/Ar plasma, the batteries exhibited better cycle performance and rate capacity than those employing the untreated ones. PMID:25971067

  12. Mobilities and longitudinal diffusion coefficients for K+ ions in nitrogen and argon

    NASA Astrophysics Data System (ADS)

    Takebe, M.; Satoh, Y.; Iinuma, K.; Seto, K.

    1980-10-01

    We have constructed a drift tube with a movable ion source and measured the mobilities and longitudinal diffusion coefficients for K+ ions at 303 °K in N2 and at 305 °K in Ar in the pressure range 0.3-5.0 Torr, over the E/N range 4-346 Td in N2 and 3-320 Td in Ar. The zero-field reduced mobilities for K+ ions in N2 and Ar were determined to be 2.50±0.03 and 2.63±0.03 cm2/V sec, respectively. Both values are in excellent agreement with the values reported by Elford and Milloy. When our data are compared with the values obtained by Thomson et al. in N2 and the values obtained by James et al. in Ar over the entire E/N range, we find that the mean deviations are about 1.7%, independent of gas species and E/N. Our zero-field reduced mobilities are about 1.2% lower in both cases than the values compiled by Ellis et al. It is concluded that the discrepancy is due to a systematic error and is not caused by clustering reactions. The mean values of NDL over the E/N range 4-7 Td in N2 and 5-10 Td in Ar were found to be 1.96×1018 and 2.09×1018 cm-1 sec-1, respectively. Both values are about 7% higher than the values calculated from our mobility data by the generalized Einstein relation and from the same parameters reported by Pai et al.

  13. Influence of Equilibration Time in Solution on the Inclusion/Exclusion Topology Ratio of Host-Guest Complexes Probed by Ion Mobility and Collision-Induced Dissociation.

    PubMed

    Carroy, Glenn; Daxhelet, Charlotte; Lemaur, Vincent; De Winter, Julien; De Pauw, Edwin; Cornil, Jérôme; Gerbaux, Pascal

    2016-03-18

    Host-guest complexes are formed by the creation of multiple noncovalent bonds between a large molecule (the host) and smaller molecule(s) or ion(s) (the guest(s)). Ion-mobility separation coupled with mass spectrometry nowadays represents an ideal tool to assess whether the host-guest complexes, when transferred to the gas phase upon electrospray ionization, possess an exclusion or inclusion nature. Nevertheless, the influence of the solution conditions on the nature of the observed gas-phase ions is often not considered. In the specific case of inclusion complexes, kinetic considerations must be taken into account beside thermodynamics; the guest ingression within the host cavity can be characterized by slow kinetics, which makes the complexation reaction kinetically driven on the timescale of the experiment. This is particularly the case for the cucurbituril family of macrocyclic host molecules. Herein, we selected para-phenylenediamine and cucurbit[6]uril as a model system to demonstrate, by means of ion mobility and collision-induced dissociation measurements, that the inclusion/exclusion topology ratio varies as a function of the equilibration time in solution prior to the electrospray process.

  14. Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

    SciTech Connect

    Joshi, Ashok V.; Balagopal, Shekar; Pendelton, Justin

    2011-12-13

    Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

  15. Ruthenium/technetium separations after the accelerator transmutation of waste: Ozonolysis vs ion-exchange

    SciTech Connect

    Schroeder, N.C.; Abney, K.D.; Kinkead, S.

    1993-12-31

    Technetium, because of its long half-life (213,000 years) and ability to migrate in the environment, is a primary contributor to the long-term radioactivity related risk associated with geologic nuclear waste disposal. One proposal for converting technetium to an environmentally benign element is its transmutation to ruthenium by reaction of {sup 99}Tc with thermal neutrons to form stable {sup 100}Ru. Los Alamos is currently investigating transmutation with an accelerator-based system (i.e, Accelerator Transmutation of Waste, ATW). Flowsheets developed for this process predict a steady state ruthenium concentration of {minus}10{sup {minus}3} M exiting the transmuter. Seperation of ruthenium from the bulk technetium solution (2 M) is required to preserve neutron economy and to prevent multiple (n, {gamma}) reactions on ruthenium leading to radioactive {sup 103,106}Ru. Ruthenium/technetium separation factors of 1200 have been achieved by ion-exchange. However, the complex chemistry of ruthenium on ion exchange resins and the disposal of the exhausted resins, required that an alternative for this 30-year old baseline technology be sought. For these reasons, volatilization of RuO{sub 4}, formed by ozonolysis of ruthenium is being considered for this separation. The results of experiments showing the violatilization efficiency using ozone will be compared to the separation of ruthenium using the baseline ion-exchange technique.

  16. Structure of salts solution in polar dielectric liquids and electrically induced separation of solvated ions

    NASA Astrophysics Data System (ADS)

    Shamanin, Igor V.; Kazaryan, Mishik A.; Sachkov, Victor I.

    2015-12-01

    The aim of study is to demonstrate that separation of solvated ions in solution of mix of salts under the action of external periodic electric field happens because of around ions there are formed clusters consisting of molecules of solvent and the sizes of such clusters have dimensions ~ 0.1 μm. In investigations the sizes of clusters theoretically were defined and experimentally value of frequency of external electric field which action excites the effect of separation of the solvated ions was defined. Experiments were done in the Technical Physics Chair of the National Research Tomsk Polytechnic University. At theoretical determination of the dimensions of clusters Poisson's equation was solved and was considered that polar molecules of solvent are oriented under the action of electric field of an ion. The chemical composition of samples of solutions was determined by means of the spectrophotometry and he X-ray excited fluorescent radiation analysis method. Theoretical estimates and results of experiments confirmed the assumption that clusters which are formed around ions in solutions have the dimensions ~ 0.1 μm. Results of investigation testify that placing of volume distributed electric charge of ion in dielectric liquid is accompanied by formation of the supramolecular particles, which we called "clusters", linear sizes of which is significantly more than first and second radiuses of solvation (~ 1 Angstrom) and reach size ~ 0.1 μm. At such sizes inertial properties of clusters and their natural frequencies give the chance to operate their movement by means of action of external electric field on solution.

  17. Combined Use of Post-Ion Mobility/Collision-Induced Dissociation and Chemometrics for b Fragment Ion Analysis

    NASA Astrophysics Data System (ADS)

    Zekavat, Behrooz; Miladi, Mahsan; Becker, Christopher; Munisamy, Sharon M.; Solouki, Touradj

    2013-09-01

    Although structural isomers may yield indistinguishable ion mobility (IM) arrival times and similar fragment ions in tandem mass spectrometry (MS), it is demonstrated that post-IM/collision-induced dissociation MS (post-IM/CID MS) combined with chemometrics can enable independent study of the IM-overlapped isomers. The new approach allowed us to investigate the propensity of selected b type fragment ions from AlaAlaAlaHisAlaAlaAla-NH2 (AAA(His)AAA) heptapeptide to form different isomers. Principle component analysis (PCA) of the unresolved post-IM/CID profiles indicated the presence of two different isomer types for b4 +, b5 +, and b6 + and a single isomer type for b7 + fragments of AAA(His)AAA. We employed a simple-to-use interactive self-modeling mixture analysis (SIMPLISMA) to calculate the total IM profiles and CID mass spectra of b fragment isomers. The deconvoluted CID mass spectra showed discernible fragmentation patterns for the two isomers of b4 +, b5 +, and b6 + fragments. Under our experimental conditions, calculated percentages of the "cyclic" isomers (at the 95 % confidence level for n = 3) for b4 +, b5 +, and b6 + were 61 (± 5) %, 36 (± 5) %, and 48 (± 2) %, respectively. Results from the SIMPLISMA deconvolution of b5 + species resembled the CID MS patterns of fully resolved IM profiles for the two b5 + isomers. The "cyclic" isomers for each of the two-component b fragment ions were less susceptible to ion fragmentation than their "linear" counterparts.

  18. Drift Tube Measurements of Mobilities and Longitudinal Diffusion Coefficients of Ions in Gases.

    NASA Astrophysics Data System (ADS)

    Chelf, Roger Dale

    The zero-field mobilities of Br('-) and NH(,4)('+) in O(,2) were determined as a function of gas temperature in a high pressure drift tube mass spectrometer. The mobilities and longitudinal diffusion coefficients of the ion-gas combinations Br('-) in Ne and Kr, Li('+) in Xe, and Tl('+) in Kr and Xe were determined as a function of E/N, where E is the electric field strength and N is the gas number density in a low pressure drift tube mass spectrometer. The measured longitudinal diffusion coefficients were used for a test and comparison of the generalized Einstein relations of Viehland-Mason and Waldman-Mason theories. The measured mobilities of Br('-) in Kr and Tl('+) in Kr were used in an iterative-inversion scheme from which the ion-neutral interaction potentials were determined. The zero-field reduced mobility of Br('-) in O(,2) ranged from 2.6 cm('2)/(V-sec) at 297(DEGREES)K to 3.0 cm('2)/(V-sec) at 600(DEGREES)K. The zero-field reduced mobility of NH(,4)('+) in O(,2) ranged from 3.4 cm('2)/(V -sec) at 418(DEGREES)K to 3.7 cm('2)/(V-sec) at 561(DEGREES)K. The zero-field values of the reduced mobilities measured as a function of E/N in units of cm('2)/(V-sec) are as follows: Br('-) in Kr (1.47 (+OR-) .03), Br('-) in Ne (6.94 (+OR -) .14), Li('+) in Xe (2.68 (+OR-) .05), Tl('+) in Kr (1.15 (+OR-) .03), and Tl('+) in Xe (.78 (+OR-) .02). The ion -gas combinations of Br('-) in Kr, Li('+) in Xe, and Tl('+) in Kr displayed the typical mobility peaks. The peak values in cm('2)/(V-sec) are for Br('-) in Kr, Li('+) in Xe, and Tl('+) in Kr respectively: (1.81 (+OR-) 0.4) at 130 Td, 4.47 (+OR-) .09 at 135 Td, and 1.42 (+OR-) .04 at 285 Td. The measured longitudinal diffusion coefficients were compared to the Einstein values in the low-field limit. Comparisons between the experimental values and the generalized Einstein relations (GER) of Viehland-Mason and Waldman-Mason were made at all E/N values. All comparisons were favorable within the error ranges. In general, the

  19. Ion mobility spectrometry-mass spectrometry studies of ion processes in air at atmospheric pressure and their application to thermal desorption of 2,4,6-trinitrotoluene

    NASA Astrophysics Data System (ADS)

    Sabo, Martin; Malásková, Michaela; Matejčík, Štefan

    2014-02-01

    In this study we have investigated the negative reactant ion formation in a negative corona discharge (CD) using the corona discharge ion mobility spectrometry orthogonal acceleration time-of-flight (CD-IMS-oaTOF) technique. The reactant ions were formed in the CD operating in the reverse gas flow mode at an elevated temperature of 363.5 K in synthetic and ambient air. Under these conditions mainly O_{2}^{-} and their clusters were formed. We have also studied the influence of CCl4 admixture to air (dopant gas) on the composition of the reactant ions, which resulted in the formation of Cl- and its clusters with a reduced ion mobility of 3.05 cm2 V-1 s-1 as a major reactant ion peak. Additional IMS peaks with reduced ion mobilities of 2.49, 2.25 and 2.03 cm2 V-1 s-1 were detected, and Cl- · (NO2) and Cl- · (NO)n(n = 2, 3) anions were identified. The negative reactant ions were used to detect 2,4,6 trinitrotoluene (TNT) using the thermal desorption (TD) technique using a CD-IMS instrument. Using TD sampling and a negative CD ion source doped by CCl4 we have achieved a limit of detection of 350 pg for direct surface analysis of TNT.

  20. Methods development for separation of inorganic anions, organic acids and bases, and neutral organic compounds by ion chromatography and capillary electrophoresis

    SciTech Connect

    Li, J.

    1999-04-01

    A novel anion-exchange resin containing three amine groups was prepared by reaction of a chloromethylated polystyrene-divinylbenzene (PS-DVB) resin with diethylenetriamine. After being protonated by contact with an aqueous acid, this resin can be used for ion chromatographic separation of anions. The charge on the resins can be varied from +1 to +3 by changing the mobile phase pH. The selectivity of the new ion exchangers for various inorganic anions was quite different from that of conventional anion exchangers. The performance of this new anion exchanger was studied by changing the pH and the concentration of the eluent, and several different eluents were used with some common anions as testing analytes. Conductivity detection and UV-visible detection were applied to detect the anions after separation. The new resin can also be used for HPLC separation of neutral organic compounds. Alkylphenols and alkylbenzenes were separated with this new polymeric resin, and excellent separations were obtained under simple conditions. This report contains Chapter 1: General introduction and Chapter 6: General conclusions.

  1. Interaction of High Flash Point Electrolytes and PE-Based Separators for Li-Ion Batteries.

    PubMed

    Hofmann, Andreas; Kaufmann, Christoph; Müller, Marcus; Hanemann, Thomas

    2015-01-01

    In this study, promising electrolytes for use in Li-ion batteries are studied in terms of interacting and wetting polyethylene (PE) and particle-coated PE separators. The electrolytes are characterized according to their physicochemical properties, where the flow characteristics and the surface tension are of particular interest for electrolyte-separator interactions. The viscosity of the electrolytes is determined to be in a range of η = 4-400 mPa∙s and surface tension is finely graduated in a range of γL = 23.3-38.1 mN∙m(-1). It is verified that the technique of drop shape analysis can only be used in a limited matter to prove the interaction, uptake and penetration of electrolytes by separators. Cell testing of Li|NMC half cells reveals that those cell results cannot be inevitably deduced from physicochemical electrolyte properties as well as contact angle analysis. On the other hand, techniques are more suitable which detect liquid penetration into the interior of the separator. It is expected that the results can help fundamental researchers as well as users of novel electrolytes in current-day Li-ion battery technologies for developing and using novel material combinations. PMID:26343636

  2. Interaction of High Flash Point Electrolytes and PE-Based Separators for Li-Ion Batteries.

    PubMed

    Hofmann, Andreas; Kaufmann, Christoph; Müller, Marcus; Hanemann, Thomas

    2015-08-27

    In this study, promising electrolytes for use in Li-ion batteries are studied in terms of interacting and wetting polyethylene (PE) and particle-coated PE separators. The electrolytes are characterized according to their physicochemical properties, where the flow characteristics and the surface tension are of particular interest for electrolyte-separator interactions. The viscosity of the electrolytes is determined to be in a range of η = 4-400 mPa∙s and surface tension is finely graduated in a range of γL = 23.3-38.1 mN∙m(-1). It is verified that the technique of drop shape analysis can only be used in a limited matter to prove the interaction, uptake and penetration of electrolytes by separators. Cell testing of Li|NMC half cells reveals that those cell results cannot be inevitably deduced from physicochemical electrolyte properties as well as contact angle analysis. On the other hand, techniques are more suitable which detect liquid penetration into the interior of the separator. It is expected that the results can help fundamental researchers as well as users of novel electrolytes in current-day Li-ion battery technologies for developing and using novel material combinations.

  3. Interaction of High Flash Point Electrolytes and PE-Based Separators for Li-Ion Batteries

    PubMed Central

    Hofmann, Andreas; Kaufmann, Christoph; Müller, Marcus; Hanemann, Thomas

    2015-01-01

    In this study, promising electrolytes for use in Li-ion batteries are studied in terms of interacting and wetting polyethylene (PE) and particle-coated PE separators. The electrolytes are characterized according to their physicochemical properties, where the flow characteristics and the surface tension are of particular interest for electrolyte–separator interactions. The viscosity of the electrolytes is determined to be in a range of η = 4–400 mPa∙s and surface tension is finely graduated in a range of γL = 23.3–38.1 mN∙m−1. It is verified that the technique of drop shape analysis can only be used in a limited matter to prove the interaction, uptake and penetration of electrolytes by separators. Cell testing of Li|NMC half cells reveals that those cell results cannot be inevitably deduced from physicochemical electrolyte properties as well as contact angle analysis. On the other hand, techniques are more suitable which detect liquid penetration into the interior of the separator. It is expected that the results can help fundamental researchers as well as users of novel electrolytes in current-day Li-ion battery technologies for developing and using novel material combinations. PMID:26343636

  4. Polyethylene terephthalate/poly (vinylidene fluoride) composite separator for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Huang, Shaohua; Xu, Zhiqin; Xiao, Zhiming; Shi, Chuan; Zhao, Jinbao; Zhu, Rui; Sun, Daoheng; Lin, Liwei

    2015-07-01

    Electrospun nanofiber membranes have been proved to enhance performances of Li-ion batteries, but their poor mechanical strength hinders their industrial application. This paper combines meltblown polyethylene terephthalate (PET) nonwoven and electrospun poly (vinylidene fluoride) (PVDF) membrane together to improve the mechanical property via hot-pressing, wherein a dried 3 wt% PVDF solution coating on PET nonwoven is used as a binder. The hot-pressing temperature is optimized to be 145 °C and the composite PET/PVDF separator exhibits an excellent mechanical property, whose transverse and longitudinal tensile strength could reach 13.70 and 34.85 MPa respectively. Compared with a commercial PP separator, the hot-pressed PET/PVDF membrane separator shows better wettability, higher thermal shrinkage and improved electrochemical performance as well.

  5. Polyethylene terephthalate/poly(vinylidene fluoride) composite separator for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Huang, Shaohua; Xu, Zhiqin; Xiao, Zhiming; Shi, Chuan; Zhao, Jinbao; Zhu, Rui; Sun, Daoheng; Lin, Liwei

    2015-06-01

    Electrospun nanofiber membranes have been proved to enhance the performance of a Li-ion battery (LIB), but their poor mechanical strength hinders their industrial application. This paper combines a meltblown polyethylene terephthalate (PET) nonwoven and a electrospun poly(vinylidene fluoride) (PVDF) membrane together to improve the mechanical property via hot-pressing, wherein a dried 3 wt% PVDF solution coating on PET nonwoven is used as a binder. The experiment results indicate that the hot-pressing PET/PVDF separator exhibits an excellent mechanical property, whose transverse and longitudinal tensile strength could reach 13.70 MPa and 34.85 MPa respectively. Compared with a commercial PP separator, the hot-pressing PET/PVDF membrane separator shows better wettability, higher thermal shrinkage and excellent discharge capacity as well.

  6. Development of Advanced Nuclide Separation and Recovery Methods using Ion-Exchanhge Techniques in Nuclear Backend

    NASA Astrophysics Data System (ADS)

    Miura, Hitoshi

    The development of compact separation and recovery methods using selective ion-exchange techniques is very important for the reprocessing and high-level liquid wastes (HLLWs) treatment in the nuclear backend field. The selective nuclide separation techniques are effective for the volume reduction of wastes and the utilization of valuable nuclides, and expected for the construction of advanced nuclear fuel cycle system and the rationalization of waste treatment. In order to accomplish the selective nuclide separation, the design and synthesis of novel adsorbents are essential for the development of compact and precise separation processes. The present paper deals with the preparation of highly functional and selective hybrid microcapsules enclosing nano-adsorbents in the alginate gel polymer matrices by sol-gel methods, their characterization and the clarification of selective adsorption properties by batch and column methods. The selective separation of Cs, Pd and Re in real HLLW was further accomplished by using novel microcapsules, and an advanced nuclide separation system was proposed by the combination of selective processes using microcapsules.

  7. Application of Ion Mobility-Mass Spectrometry to the Study of Ionic Clusters: Investigation of Cluster Ions with Stable Sizes and Compositions

    PubMed Central

    Ohshimo, Keijiro; Komukai, Tatsuya; Takahashi, Tohru; Norimasa, Naoya; Wu, Jenna Wen Ju; Moriyama, Ryoichi; Koyasu, Kiichirou; Misaizu, Fuminori

    2014-01-01

    Stable cluster sizes and compositions have been investigated for cations and anions of ionic bond clusters such as alkali halides and transition metal oxides by ion mobility-mass spectrometry (IM-MS). Usually structural information of ions can be obtained from collision cross sections determined in IM-MS. In addition, we have found that stable ion sizes or compositions were predominantly produced in a total ion mass spectrum, which was constructed from the IM-MS measurement. These stable species were produced as a result of collision induced dissociations of the ions in a drift cell. We have confirmed this result in the sodium fluoride cluster ions, in which cuboid magic number cluster ions were predominantly observed. Next the stable compositions, which were obtained for the oxide systems of the first row transition metals, Ti, Fe, and Co, are characteristic for each of the metal oxide cluster ions. PMID:26819887

  8. Studies of ion species separation in ICF-relevant plasmas at OMEGA

    NASA Astrophysics Data System (ADS)

    Rinderknecht, Hans; Wilks, Scott; Amendt, Peter; Ross, Steve; Park, Hye-Sook; Gatu Johnson, Maria; Frenje, Johan; Li, Chikang; Seguin, Fredrick; Sio, Hong; Petrasso, Richard; Rosenberg, Michael; Forrest, Chad; Glebov, Vladimir; Stoeckl, Christian; Sangster, Craig; Zylstra, Alex; Hoffman, Nelson; Kwan, Tom; Larroche, Olivier

    2015-11-01

    Plasmas produced in high-energy density (HED) and inertial confinement fusion (ICF) experiments generally contain multiple ion species, which allows for multiple-ion species dynamics that are not simulated in typical single-ion fluid hydro codes. In implosions of D3He-gas filled thin-glass spheres on the OMEGA laser facility, comprehensive nuclear diagnostics were used to infer the composition of the fuel during nuclear production, demonstrating that the deuterium fraction was reduced during the implosion of the fuel. Hydrodynamic simulations including an ion diffusion model indicate that pressure, temperature, and potential gradients drive diffusive separation of the ion species, producing better agreement with the experiments than standard hydrodynamic codes. The results of fully kinetic (Vlasov-Fokker-Planck and PIC) simulations confirm the importance of multi-species dynamics to the evolution of these experiments. Implications for multi-species (DT) cryogenic implosions on the National Ignition Facility will be addressed. This work was partially supported by the US DOE, NLUF, LLE, and GA.

  9. Partition Coefficients of Selected Compounds Using Ion Exchange Separation of Cesium From High Level Waste

    SciTech Connect

    Toth, James J.; Blanchard, David L.; Arm, Stuart T.; Urie, Michael W.

    2004-04-24

    The removal of cesium radioisotope (137Cs) from the High Level Waste stored in underground storage tanks at the Hanford site is a formidable chemical separations challenge for the Waste Treatment Plant. An eluatable organic-based ion exchange resin was selected as the baseline technology (1). The baseline technology design employs a proprietary macrocyclic weak-acid ion exchange resin to adsorb the cesium (137Cs) during the process loading cycle in a fixed bed column design. Following loading, the cesium is eluted from the resin using a nitric acid eluant. Previous work provided limited understanding of the performance of the resin, processed with actual wastes, and under multiple load and elute conditions, which are required for the ion exchange technology to be underpinned sufficiently for resolution of all process-related design issues before flowsheet and construction drawings can be released. By performing multiple ion exchange column tests with waste feeds, and measuring the chemical and radionuclide compositions of the waste feeds, column effluents and column eluants, ion exchange stream composition information can be provided for supporting resolution of selected design issues.

  10. Ion Mobility Mass Spectrometry for Ion Recovery and Clean-Up of MS and MS/MS Spectra Obtained from Low Abundance Viral Samples

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Crispin, Max; Bonomelli, Camille; Scrivens, Jim H.

    2015-07-01

    Many samples of complex mixtures of N-glycans released from small amounts of material, such as glycoproteins from viruses, present problems for mass spectrometric analysis because of the presence of contaminating material that is difficult to remove by conventional methods without involving sample loss. This study describes the use of ion mobility for extraction of glycan profiles from such samples and for obtaining clean CID spectra when targeted m/z values capture additional ions from those of the target compound. N-glycans were released enzymatically from within SDS-PAGE gels, from the representative recombinant glycoprotein, gp120 of the human immunodeficiency virus, and examined by direct infusion electrospray in negative mode followed by ion mobility with a Waters Synapt G2 mass spectrometer (Waters MS-Technologies, Manchester, UK). Clean profiles of singly, doubly, and triply charged N-glycans were obtained from samples in cases where the raw electrospray spectra displayed only a few glycan ions as the result of low sample concentration or the presence of contamination. Ion mobility also enabled uncontaminated CID spectra to be obtained from glycans when their molecular ions displayed coincidence with ions from fragments or multiply charged ions with similar m/z values. This technique proved to be invaluable for removing extraneous ions from many CID spectra. The presence of such ions often produces spectra that are difficult to interpret. Most CID spectra, even those from abundant glycan constituents, benefited from such clean-up, showing that the extra dimension provided by ion mobility was invaluable for studies of this type.

  11. Ion Mobility Mass Spectrometry for Ion Recovery and Clean-Up of MS and MS/MS Spectra Obtained from Low Abundance Viral Samples.

    PubMed

    Harvey, David J; Crispin, Max; Bonomelli, Camille; Scrivens, Jim H

    2015-10-01

    Many samples of complex mixtures of N-glycans released from small amounts of material, such as glycoproteins from viruses, present problems for mass spectrometric analysis because of the presence of contaminating material that is difficult to remove by conventional methods without involving sample loss. This study describes the use of ion mobility for extraction of glycan profiles from such samples and for obtaining clean CID spectra when targeted m/z values capture additional ions from those of the target compound. N-glycans were released enzymatically from within SDS-PAGE gels, from the representative recombinant glycoprotein, gp120 of the human immunodeficiency virus, and examined by direct infusion electrospray in negative mode followed by ion mobility with a Waters Synapt G2 mass spectrometer (Waters MS-Technologies, Manchester, UK). Clean profiles of singly, doubly, and triply charged N-glycans were obtained from samples in cases where the raw electrospray spectra displayed only a few glycan ions as the result of low sample concentration or the presence of contamination. Ion mobility also enabled uncontaminated CID spectra to be obtained from glycans when their molecular ions displayed coincidence with ions from fragments or multiply charged ions with similar m/z values. This technique proved to be invaluable for removing extraneous ions from many CID spectra. The presence of such ions often produces spectra that are difficult to interpret. Most CID spectra, even those from abundant glycan constituents, benefited from such clean-up, showing that the extra dimension provided by ion mobility was invaluable for studies of this type.

  12. Ion mobility mass spectrometry as a potential tool to assign disulfide bonds arrangements in peptides with multiple disulfide bridges.

    PubMed

    Echterbille, Julien; Quinton, Loïc; Gilles, Nicolas; De Pauw, Edwin

    2013-05-01

    Disulfide bridges play a major role in defining the structural properties of peptides and proteins. However, the determination of the cysteine pairing is still challenging. Peptide sequences are usually achieved using tandem mass spectrometry (MS/MS) spectra of the totally reduced unfolded species, but the cysteine pairing information is lost. On the other hand, MS/MS experiments performed on native folded species show complex spectra composed of nonclassical ions. MS/MS alone does not allow either the cysteine pairing or the full sequence of an unknown peptide to be determined. The major goal of this work is to set up a strategy for the full structural characterization of peptides including disulfide bridges annotation in the sequence. This strategy was developed by combining ion mobility spectrometry (IMS) and collision-induced dissociation (CID). It is assumed that the opening of one S-S bridge in a peptide leads to a structural evolution which results in a modification of IMS drift time. In the presence of multiple S-S bridges, the shift in arrival time will depend on which disulfide(s) has (have) been reduced and on the shape adopted by the generated species. Due to specific fragmentations observed for each species, CID experiments performed after the mobility separation could provide not only information on peptide sequence but also on the localization of the disulfide bridges. To achieve this goal, synthetic peptides containing two disulfides were studied. The openings of the bridges were carried out following different experimental conditions such as reduction, reduction/alkylation, or oxidation. Due to disulfide scrambling highlighted with the reduction approaches, oxidation of S-S bonds into cysteic acids appeared to be the best strategy. Cysteine connectivity was then unambiguously determined for the two peptides, without any disulfide scrambling interference.

  13. Experimental ion mobility measurements in Ar-C2H6 mixtures

    NASA Astrophysics Data System (ADS)

    Cortez, A. F. V.; Garcia, A. N. C.; Neves, P. N. B.; Santos, F. P.; Borges, F. I. G. M.; Barata, J. A. S.; Conde, C. A. N.

    2013-12-01

    In this paper we present the experimental results for the mobility of ions in argon-ethane gaseous mixtures (Ar-C2H6) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature. For Ar concentrations below 80% two peaks were observed in the time of arrival spectra which were attributed to ion species with 3-carbons (C3H7+, C3H8+ and C3H9+) and with 4-carbons (which includes C4H7+, C4H9+, C4H10+ and C4H12+ ions). For Ar concentrations above 80% a third peak appears, which may belong to C5H11+. The time of arrival spectra for Ar concentrations of 80%, 85%, 90% and 95% are displayed in the present paper as well as the reduced mobilities determined from the peaks observed for a typical reduced electric field used in gaseous detectors (E/N = 15 Td).

  14. The analysis of methamphetamine hydrochloride by thermal desorption ion mobility spectrometry and SIMPLISMA.

    PubMed

    Reese, E S; Harrington, P B

    1999-01-01

    Ion mobility spectrometry (IMS) has been successfully developed to yield an advanced portable instrument. Such instruments may detect trace quantities of regulated substances at the crime scene. The atmospheric ion chemistry that occurs within