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Redeker FA, O’Malley K, McMahon WP, Jorabchi K. Solution Cathode Glow Discharge Coupled to Atmospheric Pressure Chemical Ionization for Elemental Detection of S and P in Organic Compounds. SPECTROCHIMICA ACTA. PART B, ATOMIC SPECTROSCOPY 2024; 212:106858. [PMID: 38292419 PMCID: PMC10824527 DOI: 10.1016/j.sab.2024.106858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
We report a post-plasma chemical ionization approach to evaluate solution cathode glow discharge (SCGD) for S and P elemental analysis. Here, the SCGD serves as a reactor to produce chemical vapors for S and P from organic compounds containing these elements, while a corona discharge operated in negative mode is used to ionize the products. The approach creates long-lived ions in atmospheric pressure, enabling direct investigation of chemical vapor products via mass spectrometric and ion mobility separations. The investigations indicate that SCGD converts S and P to H2SO4 and H3PO4, respectively. These species are then ionized as HSO4HNO3 - and H3PO4NO3HNO3- via reactions with NO3HNO3- produced by corona discharge. The response factors for P among several small molecules varies within 10% of the average response from the compounds, suggesting a reasonable species-independent characteristic. The response factors for S show larger variations among compounds, indicating a higher dependence of chemical vapor generation efficiency on analytes' chemical structures. Detection limits of 15 and 29 ng/mL are achieved for P and S detection, respectively. These figures are limited by background equivalent concentrations and low ion flux in the utilized ion mobility-time of flight mass spectrometer, indicating potential for significant improvements. In particular, the specificity of clustering for S and P-containing ions produced in this approach suggest facile analysis of S and P using quadrupole-based mass spectrometers for improved analytical performance.
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Affiliation(s)
- Frenio A. Redeker
- Department of Chemistry, Georgetown University, 37 and O streets, NW, Washington, DC 20057, USA
| | - Kelsey O’Malley
- Department of Chemistry, Georgetown University, 37 and O streets, NW, Washington, DC 20057, USA
| | | | - Kaveh Jorabchi
- Department of Chemistry, Georgetown University, 37 and O streets, NW, Washington, DC 20057, USA
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2
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Li H, Allen N, Li M, Li A. Conducting and characterizing femto flow electrospray ionization. Analyst 2022; 147:1071-1075. [PMID: 35195636 DOI: 10.1039/d1an02190g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Femto flow electrospray ionization (ESI) with flow rates ranging from 240 fL min-1 to the low pico level (<10 pL min-1) was conducted and measured using a submicron emitter tip and relay ESI configuration. Signature analyte ion current intensities and profiles were observed. The obtained flow rate and ionization current enabled size calculation for initial charged nanodroplets.
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Affiliation(s)
- Huishan Li
- Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, NH 03824, USA.
| | - Nicholas Allen
- Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, NH 03824, USA.
| | - Mengtian Li
- Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, NH 03824, USA.
| | - Anyin Li
- Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, NH 03824, USA.
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3
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Peng X, Wang Z. Systematic evaluation of advance in application and discharge mechanism of solution electrode glow discharge. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2021.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Molnar BT, Shelley JT. MODERN PLASMA-BASED DESORPTION/IONIZATION: FROM ATOMS AND MOLECULES TO CHEMICAL SYNTHESIS. MASS SPECTROMETRY REVIEWS 2021; 40:609-627. [PMID: 32770688 DOI: 10.1002/mas.21645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/05/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Since the first mass spectrometry (MS) experiments were conducted by Thomson and Aston, plasmas have been used as ionization sources. Historically, plasma ion sources were used for these experiments because they were one of the few known sources of gas-phase ions at the time and they were relatively simple to setup and operate. Since then, developments in plasma ionization have continued to inform and motivate advances in other areas of MS. For example, plasma-desorption MS demonstrated ionization of large peptides and polymers more than 10 years before the first descriptions of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). As a result, significant effort was placed on development of ionization approaches, mass analysis, and detection approaches for very large molecules: even before the advent of ESI and MALDI. Since then, new analytical challenges and opportunities in plasma ionization have arisen. In this review, the emerging trends in plasma-based ionization for several areas of MS will be discussed, including molecular ionization, elemental ionization, hybrid elemental and molecular ion sources, and unique chemical transformations. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Brian T Molnar
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180
| | - Jacob T Shelley
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180
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Aghaei M, Bogaerts A. Flowing Atmospheric Pressure Afterglow for Ambient Ionization: Reaction Pathways Revealed by Modeling. Anal Chem 2021; 93:6620-6628. [PMID: 33877800 DOI: 10.1021/acs.analchem.0c04076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the plasma chemistry in a helium flowing atmospheric pressure afterglow (FAPA) used for analytical spectrometry, by means of a quasi-one-dimensional (1D) plasma chemical kinetics model. We study the effect of typical impurities present in the feed gas, as well as the afterglow in ambient humid air. The model provides the species density profiles in the discharge and afterglow regions and the chemical pathways. We demonstrate that H, N, and O atoms are formed in the discharge region, while the dominant reactive neutral species in the afterglow are O3 and NO. He* and He2* are responsible for Penning ionization of O2, N2, H2O, H2, and N, and especially O and H atoms. Besides, He2+ also contributes to ionization of N2, O2, H2O, and O through charge transfer reactions. From the pool of ions created in the discharge, NO+ and (H2O)3H+ are the dominant ions in the afterglow. Moreover, negatively charged clusters, such as NO3H2O- and NO2H2O-, are formed and their pathway is discussed as well. Our model predictions are in line with earlier observations in the literature about the important reagent ions and provide a comprehensive overview of the underlying pathways. The model explains in detail why helium provides a high analytical sensitivity because of high reagent ion formation by both Penning ionization and charge transfer. Such insights are very valuable for improving the analytical performance of this (and other) ambient desorption/ionization source(s).
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Affiliation(s)
- Maryam Aghaei
- Research group PLASMANT, Chemistry Department, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Annemie Bogaerts
- Research group PLASMANT, Chemistry Department, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
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Li M, Li H, Allen NR, Wang T, Li L, Schwartz J, Li A. Nested-channel for on-demand alternation between electrospray ionization regimes. Chem Sci 2020; 12:1907-1914. [PMID: 34163954 PMCID: PMC8179270 DOI: 10.1039/d0sc06221a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
On-demand electrospray ionization from different liquid channels in the same emitter was realized using filamented capillary and gas phase charge supply. The solution sub-channel was formed when back-filling solution to the emitter tip by capillary action along the filament. Gas phase charge carriers were used to trigger electrospray ionization from the solution meniscus at the tip. The meniscus at the tip opening may be fully filled or partially empty to generate electrospray ionization in main-channel regime and sub-channel regime, respectively. For emitters with 4 μm tip opening, the two nested electrospray (nested-ESI) channels accommodated ESI flow rates ranging from 50 pL min−1 to 150 nL min−1. The platform enabled on-demand regime alternations within one sample run, in which the sub-channel regime generated smaller charged droplets. Ionization efficiencies for saccharides, glycopeptide, and proteins were enhanced in the sub-channel regime. Non-specific salt adducts were reduced and identified by regime alternation. Surprisingly, the sub-channel regime produced more uniform responses for a peptide mixture whose relative ionization efficiencies were insensitive to ESI conditions in previous picoelectrospray study. The nested channels also allowed effective washing of emitter tip for multiple sampling and analysis operations. Nested electrospray ionization alternates on-demand between microscale main-channel and nanscale sub-channels.![]()
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Affiliation(s)
- Mengtian Li
- Department of Chemistry, University of New Hampshire 23 Academic Way Durham NH 03824 USA
| | - Huishan Li
- Department of Chemistry, University of New Hampshire 23 Academic Way Durham NH 03824 USA
| | - Nicholas R Allen
- Department of Chemistry, University of New Hampshire 23 Academic Way Durham NH 03824 USA
| | - Taoqing Wang
- Department of Chemistry, University of New Hampshire 23 Academic Way Durham NH 03824 USA
| | - Linfan Li
- Thermo Fisher Scientific 355 River Oaks Pkwy San Jose CA 95134 USA
| | - Jae Schwartz
- Thermo Fisher Scientific 355 River Oaks Pkwy San Jose CA 95134 USA
| | - Anyin Li
- Department of Chemistry, University of New Hampshire 23 Academic Way Durham NH 03824 USA
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Modeling plasmas in analytical chemistry-an example of cross-fertilization. Anal Bioanal Chem 2020; 412:6059-6083. [PMID: 32236655 DOI: 10.1007/s00216-020-02587-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 02/24/2020] [Accepted: 03/09/2020] [Indexed: 10/24/2022]
Abstract
This paper gives an overview of the modeling work developed in our group in the last 25 years for various plasmas used in analytical spectrochemistry, i.e., glow discharges (GDs), inductively coupled plasmas (ICPs), and laser ablation (LA) for sample introduction in the ICP and for laser-induced breakdown spectroscopy (LIBS). The modeling approaches are briefly presented, which are different for each case, and some characteristic results are illustrated. These plasmas are used not only in analytical chemistry but also in other applications, and the insights obtained in these other fields were quite helpful for us to develop models for the analytical plasmas. Likewise, there is now a huge interest in plasma-liquid interaction, atmospheric pressure glow discharges (APGDs), and dielectric barrier discharges (DBDs) for environmental, medical, and materials applications of plasmas. The insights obtained in these fields are also very relevant for ambient desorption/ionization sources and for liquid sampling, which are nowadays very popular in analytical chemistry, and they could be very helpful in developing models for these sources as well. Graphical abstract.
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You Y, Badal SP, Shelley JT. Automatic Analyte-Ion Recognition and Background Removal for Ambient Mass-Spectrometric Data Based on Cross-Correlation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1720-1732. [PMID: 31161333 DOI: 10.1007/s13361-019-02246-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/17/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
Ambient mass spectrometry is a powerful approach for rapid, high-throughput, and direct sample analysis. Due to the open-air desorption and ionization processes, random fluctuations of ambient conditions can lead to large variances in mass-spectral signals over time. The mass-spectral data also can be further complicated due to multiple analytes present in the sample, background-ion signals stemming from the desorption/ionization source itself, and other laboratory-specific conditions (e.g., ambient laboratory air, nearby hardware). Thus, background removal and analyte-ion recognition can be quite difficult, particularly in non-targeted analyses. Here, we demonstrate the use of a cross-correlation-based approach to exploit chemical information encoded in the time domain to group/categorize mass-spectral peaks from a single analysis dataset. Ions that originate from ambient (or other) background species were readily flagged and removed from spectra; the result was a decrease in mass-spectral complexity by over 70% due to the removal of these background ions. Meanwhile, analyte ions were differentiated and categorized based on their time-domain profiles. With sufficient mass resolving-power and mass-spectral acquisition rate, isolated mass spectra containing ions from the same species in a sample could be extracted, leading to a reduction in mass-spectral complexity by more than 98% in some cases. The cross-correlation approach was tested with different ionization sources as well as reproducible and irreproducible sample introduction. Software built in-house enabled fully automated data processing, which can be performed within a few seconds. Ultimately, this approach provides an additional dimension of analyte separation in ambient mass-spectrometric analyses with information that is already recorded throughout the analysis.
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Affiliation(s)
- Yi You
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
| | - Sunil P Badal
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Jacob T Shelley
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA.
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
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Bierstedt A, You Y, van Wasen S, Bosc-Bierne G, Weller M, Riedel J. Laser-Induced Microplasma as an Ambient Ionization Approach for the Mass-Spectrometric Analysis of Liquid Samples. Anal Chem 2019; 91:5922-5928. [DOI: 10.1021/acs.analchem.9b00329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas Bierstedt
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Yi You
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Sebastian van Wasen
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Gaby Bosc-Bierne
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Michael Weller
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Jens Riedel
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
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Schrader RL, Ayrton ST, Kaerner A, Cooks RG. High-throughput, low-cost reaction screening using a modified 3D printer. Analyst 2019; 144:4978-4984. [PMID: 31322145 DOI: 10.1039/c9an00785g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe a reaction screening system, based on a 96-well array, and scaled to suit use on the individual scientist's bench. The system was built by modifying a desktop 3D printer and fitting it with a glass syringe and microtiter plate. The effects of experimental variables were characterized, and the performance of the system was optimized. Precise volumes of reaction mixtures (<3% CV) were dispensed into the 96-well array in ca. 40 minutes. The system was used to screen reagents and solvents for the N-alkylation, Katritzky transamination, and Suzuki cross-coupling reactions. Product distributions derived from electrospray mass spectra and represented as heat maps facilitated recognition of optimum conditions. Screening of 96 reaction mixtures was completed in the modest time of approximately 105 minutes (∼65 seconds per reaction mixture). The system is constructed from open-source software and inexpensive 3D printer hardware.
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Affiliation(s)
- Robert L Schrader
- Purdue University Department of Chemistry, West Lafayette, IN 47907, USA.
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11
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Song L, You Y, Evans-Nguyen T. Surface Acoustic Wave Nebulization with Atmospheric-Pressure Chemical Ionization for Enhanced Ion Signal. Anal Chem 2018; 91:912-918. [PMID: 30481449 DOI: 10.1021/acs.analchem.8b03927] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Many ambient desorption/ionization mass spectrometry (ADI-MS) techniques rely critically on thermal desorption. Meanwhile, the analyte classes that are successfully studied by any particular ADI-MS methods are strongly dependent on the type of ionization source. Generally, spray-based ionization sources favor polar analytes, whereas plasma-based sources can be used for more hydrophobic analytes and are more suitable for molecules with small molar masses. In the present work, classic atmospheric-pressure chemical ionization (APCI) is used. To provide improved desorption performance for APCI, a surface acoustic wave nebulization (SAWN) device was implemented to convert liquid analytes into fine airborne particles. Compared to conventional SAWN that is used solely as an ionization source for liquid samples, the coupling of SAWN and APCI significantly improves ion signal by up to 4 orders of magnitude, reaching comparable ion abundances to those of electrospray ionization (ESI). Additionally, this coupling also extends the applicable mass range of an APCI source, conventionally known for the ionization of small molecules <500 Da. Herein, we discuss cursory evidence of this applicability to a variety of analytes including both polar and nonpolar small molecules and novel peptides that mimic biomolecules upward of 1000 Da. Observed species are similar to ESI-derived ions including doubly charged analyte ions despite presumably different charging mechanisms. SAWN-APCI coupling may thus involve more nuanced ionization pathways in comparison to other ADI approaches.
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Affiliation(s)
- Linxia Song
- University of South Florida , Tampa , Florida 33620 , United States
| | - Yi You
- Federal Institute for Materials Research and Testing (BAM) , 12489 Berlin , Germany
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Atmospheric-pressure solution-cathode glow discharge: A versatile ion source for atomic and molecular mass spectrometry. Anal Chim Acta 2017; 950:119-128. [DOI: 10.1016/j.aca.2016.10.045] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/28/2016] [Accepted: 10/31/2016] [Indexed: 01/12/2023]
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