1
|
Spoorthi BK, Debnath K, Basuri P, Nagar A, Waghmare UV, Pradeep T. Spontaneous weathering of natural minerals in charged water microdroplets forms nanomaterials. Science 2024; 384:1012-1017. [PMID: 38815034 DOI: 10.1126/science.adl3364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/08/2024] [Indexed: 06/01/2024]
Abstract
In this work, we show that particles of common minerals break down spontaneously to form nanoparticles in charged water microdroplets within milliseconds. We transformed micron-sized natural minerals like quartz and ruby into 5- to 10-nanometer particles when integrated into aqueous microdroplets generated via electrospray. We deposited the droplets on a substrate, which allowed nanoparticle characterization. We determined through simulations that quartz undergoes proton-induced slip, especially when reduced in size and exposed to an electric field. This leads to particle scission and the formation of silicate fragments, which we confirmed with mass spectrometry. This rapid weathering process may be important for soil formation, given the prevalence of charged aerosols in the atmosphere.
Collapse
Affiliation(s)
- B K Spoorthi
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Koyendrila Debnath
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Pallab Basuri
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ankit Nagar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Umesh V Waghmare
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Thalappil Pradeep
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
- International Centre for Clean Water, IIT Madras Research Park, Chennai 600113, India
| |
Collapse
|
2
|
Heintz C, Schnödewind L, Braubach O, Kersten H, Benter T, Wißdorf W. Observation of Large, Charged Droplet Signatures within the High-Vacuum Region of a Commercial Electrospray TOF-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:508-517. [PMID: 38408762 DOI: 10.1021/jasms.3c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Electrospray ionization (ESI) is one of the most prominent atmospheric pressure ionization techniques in modern mass spectrometry. It generates charged droplets from an analyte-containing solution as an initial step in the ionization process. Textbooks and the majority of the articles assume the entire droplet evaporation and release of bare analyte ions within the ionization chamber. However, non-mass-spectrometry-related literature and recent reports demonstrate droplet observation in regions of the vacuum systems of a variety of mass spectrometers. In this work, we report on the observation of large droplet fragments within the orthogonal acceleration stage of a Bruker micrOTOF by connecting an oscilloscope to an auxiliary ion current detector downstream of the acceleration stage. Moreover, we detected fragment debris even with the MCP TOF detector by evaluating individual TOF spectra. Droplet fragments appear as pronounced and intensive pulses of the ion current. This observation is clearly connected to ESI, as other atmospheric pressure ionization methods do not show this behavior. The recorded droplet signatures show clear dependencies on the ion source and transfer stage parameters. The existence of large and highly charged droplets may adversely affect or at least impact the analytical performance of the instrument due to space charge or complex heterogeneous chemical reactions. Furthermore, the penetration of large charged aggregates into the vacuum system explains the reported surface contamination after multipole stages. This contamination of critical components leads to substantially higher maintenance efforts.
Collapse
Affiliation(s)
- Chris Heintz
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Lisa Schnödewind
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Oliver Braubach
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Hendrik Kersten
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Thorsten Benter
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| | - Walter Wißdorf
- Department of Physical and Theoretical Chemistry, University of Wuppertal, Gaussstraße 20, 42119 Wuppertal, Germany
| |
Collapse
|
3
|
Hsu CY, Prabhu GRD, Chang CH, Hsu PC, Buchowiecki K, Urban PL. Are Most Micrometer Droplets (>10 μm) Wasted in Electrospray Ionization? An Insight from Real-Time High-Speed Imaging. Anal Chem 2023; 95:14702-14709. [PMID: 37725015 DOI: 10.1021/acs.analchem.3c02799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Electrospray ionization (ESI) is one of the main techniques used in mass spectrometry (MS) of nonvolatile compounds. ESI is a disordered process, in which a large number of polydisperse droplets are projected from a fluctuating Taylor cone and jet protruding ESI emitter. Here, we disclose a system for sectioning electrospray plumes to discrete packets with millisecond and submillisecond lifetime, which are introduced to the MS orifice, one at a time. A high-speed camera was triggered at 10,000 frames per second to capture consecutive images of the electrospray packets transmitted to the mass spectrometer. We further correlated the high-speed images of electrospray packets with MS signals of a test analyte (acetaminophen). Following computational treatment of the images, we determined the number of droplet observations (<300), average diameter of droplets (∼10-20 μm), and average volume of droplets (few tens of picoliters) in the individual electrospray packets. The result shows that most micrometer droplets (>10 μm) do not have any significant contribution to the MS signals. This finding is in agreement with the prior conjecture that most of the MS signals are mainly attributed to nanodroplets. Based on this finding, one can deduce that only a small number of the initial microdroplets effectively carry analyte molecules that undergo ionization. We discuss that, in future, one may propose a way to "recharge" the emitted initial micrometer droplets to increase the efficiency of conventional ESI setups.
Collapse
Affiliation(s)
- Chun-Yao Hsu
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Gurpur Rakesh D Prabhu
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Ching-Han Chang
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Pin-Chieh Hsu
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Krzysztof Buchowiecki
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Pawel L Urban
- Department of Chemistry, National Tsing Hua University 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| |
Collapse
|
4
|
Rapid membrane surface functionalization with Ag nanoparticles via coupling electrospray and polymeric solvent bonding for enhanced antifouling and catalytic performance: Deposition and interfacial reaction mechanisms. J Colloid Interface Sci 2023; 639:203-213. [PMID: 36805745 DOI: 10.1016/j.jcis.2023.02.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/07/2023] [Accepted: 02/11/2023] [Indexed: 02/16/2023]
Abstract
Electrospray is an effective, fast, and potentially scalable approach for membrane surface functionalization using various engineered nanomaterials (ENMs). However, the lack of fundamental understandings of the deposition process hinders the controlled deposition, efficient utilization, and long-term stabilization of the ENMs, and thus the practical applications of the nanocomposite membranes. To bridge this critical knowledge gap, advanced online characterization techniques (laser diffraction size measurement and laser doppler velocimetry) coupled with mathematical aerosol modeling are utilized to understand the three key process parameters: droplet size, deposition velocity, and evaporation rate. After deposition, polymeric solvent bonding (i.e., interdiffusion and subsequent entanglement of polymers) was found to substantially stabilize the deposited Ag NPs. We further provide a comprehensive description of such interfacial reaction mechanisms. Our results show a consistency between theoretical predication and measurement of the droplet size or deposition velocity, whereas realistic droplet evaporation rate is lower than the theoretical value due to the addition of the polymer. Successful stabilization of Ag NPs via interfacial polymeric bonding occurs under the conditions of large material contact area, high material compatibility, proper temperature (e.g., 22 °C), and polymer-to-solvent ratio (e.g., 3-5%). Our coupled approach achieves superior Ag NP coverage with high stability within minutes. Despite some reduction in water permeance, the resultant membrane shows markedly improved catalytic and antimicrobial (antibiofouling) performance (>90% enhancement) and maintained rejection. Taken together, our findings provide fundamental insights into the coupled process of electrospray deposition and polymeric solvent bonding to enable additive manufacturing of novel nanocomposite membranes with diverse structures and multiple functions.
Collapse
|
5
|
Kloudová B, Strmeň T, Vrkoslav V, Chára Z, Pačes O, Cvačka J. Gas Dynamic Virtual Nozzle Sprayer for an Introduction of Liquid Samples in Atmospheric Pressure Ionization Mass Spectrometry. Anal Chem 2023; 95:4196-4203. [PMID: 36800482 PMCID: PMC10016749 DOI: 10.1021/acs.analchem.2c05349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Electrospray may exhibit inadequate ionization efficiency in some applications. In such cases, atmospheric-pressure chemical ionization (APCI) and photoionization (APPI) can be used. Despite a wide application potential, no APCI and APPI sources dedicated to very low sample flow rates exist on the market. Since the ion source performance depends on the transfer of analytes from the liquid to the gas phase, a nebulizer is a critical component of an ion source. Here, we report on the nebulizer with a gas dynamic virtual nozzle (GDVN) and its applicability in APCI at microliter-per-minute flow rates. Nebulizers differing by geometrical parameters were fabricated and characterized regarding the jet breakup regime, droplet size, droplet velocity, and spray angle for liquid flow rates of 0.75-15.0 μL/min. A micro-APCI source with the GDVN nebulizer behaved as a mass-flow-sensitive detector and provided stable and intense analyte signals. Compared to a classical APCI source, an order of magnitude lower detection limit for verapamil was achieved. Mass spectra recorded with the nebulizer in dripping and jetting modes were almost identical and did not differ from normal APCI spectra. Clogging never occurred during the experiments, indicating the high robustness of the nebulizer. Low-flow-rate APCI and APPI sources with a GDVN sprayer promise new applications for low- and medium-polar analytes.
Collapse
Affiliation(s)
- Barbora Kloudová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic.,Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43 Prague 2, Czech Republic
| | - Timotej Strmeň
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Vladimír Vrkoslav
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Zdeněk Chára
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Pat'ankou 30/5, CZ-166 12 Prague 6, Czech Republic
| | - Ondřej Pačes
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic.,Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 43 Prague 2, Czech Republic
| |
Collapse
|
6
|
Basuri P, Chakraborty A, Ahuja T, Mondal B, Kumar JS, Pradeep T. Spatial reorganization of analytes in charged aqueous microdroplets. Chem Sci 2022; 13:13321-13329. [PMID: 36507174 PMCID: PMC9682915 DOI: 10.1039/d2sc04589c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/11/2022] [Indexed: 12/15/2022] Open
Abstract
Imprinted charged aqueous droplets of micrometer dimensions containing spherical gold and silver nanoparticles, gold nanorods, proteins and simple molecules were visualized using dark-field and transmission electron microscopies. With such studies, we hoped to understand the unusual chemistry exhibited by microdroplets. These droplets with sizes in the range of 1-100 μm were formed using a home-built electrospray source with nitrogen as the nebulization gas. Several remarkable features such as mass/size-selective segregation and spatial localization of solutes in nanometer-thin regions of microdroplets were visualized, along with the formation of micro-nano vacuoles. Electrospray parameters such as distance between the spray tip and surface, voltage and nebulization gas pressure influenced particle distribution within the droplets. We relate these features to unusual phenomena such as the enhancement of rates of chemical reactions in microdroplets.
Collapse
Affiliation(s)
- Pallab Basuri
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India
| | - Amrita Chakraborty
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India
| | - Tripti Ahuja
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India
| | - Biswajit Mondal
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India
| | - Jenifer Shantha Kumar
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India
| | - Thalappil Pradeep
- DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology, MadrasChennai 600036India,International Centre for Clean WaterChennaiTamil Nadu 600113India
| |
Collapse
|
7
|
Kreyenschmidt F, Eisele NF, Hevelke V, Rahrt R, Kreyenschmidt A, Koszinowski K. In-Situ Analysis of Anionic Coordination Polymerizations by Electrospray-Ionization Mass Spectrometry. Angew Chem Int Ed Engl 2022; 61:e202210211. [PMID: 35977914 PMCID: PMC9828445 DOI: 10.1002/anie.202210211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Indexed: 01/12/2023]
Abstract
Anionic coordination polymerizations proceed via highly reactive intermediates, whose in situ analysis has remained difficult. Here, we show that electrospray-ionization mass spectrometry is a promising method to obtain detailed information on the polymerization process. Focusing on polymerization reactions of 1,3-dienes initiated by CoCl2 /RLi (R=Me, nBu, tBu, Ph), we directly observe the growing polymer chains and characterize the active anionic cobalt centers by gas-phase fragmentation experiments. On the basis of these results, we suggest a plausible mechanism for the polymerization reaction. Moreover, the ESI mass spectra permit the determination of molecular weight distributions, which are in good agreement with those derived from NMR-spectroscopic as well as MALDI mass-spectrometric measurements, and afford a wealth of kinetic data.
Collapse
Affiliation(s)
- Friedrich Kreyenschmidt
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstraße 237077GöttingenGermany
| | - Niklas F. Eisele
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstraße 237077GöttingenGermany
| | - Valentin Hevelke
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstraße 237077GöttingenGermany
| | - Rene Rahrt
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstraße 237077GöttingenGermany
| | | | - Konrad Koszinowski
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstraße 237077GöttingenGermany
| |
Collapse
|
8
|
Kreyenschmidt F, Eisele NF, Hevelke V, Rahrt R, Kreyenschmidt AK, Koszinowski K. In‐Situ Analysis of Anionic Coordination Polymerizations by Electrospray‐Ionization Mass Spectrometry. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Friedrich Kreyenschmidt
- Georg-August-Universität Göttingen: Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | - Niklas F. Eisele
- Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | - Valentin Hevelke
- Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | - Rene Rahrt
- Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | | | - Konrad Koszinowski
- Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie Tammannstr. 2 37077 Göttingen GERMANY
| |
Collapse
|
9
|
Walz A, Stoiber K, Huettig A, Schlichting H, Barth JV. Navigate Flying Molecular Elephants Safely to the Ground: Mass-Selective Soft Landing up to the Mega-Dalton Range by Electrospray Controlled Ion-Beam Deposition. Anal Chem 2022; 94:7767-7778. [PMID: 35609119 PMCID: PMC9178560 DOI: 10.1021/acs.analchem.1c04495] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The prototype of a highly versatile and efficient preparative mass spectrometry system used for the deposition of molecules in ultrahigh vacuum (UHV) is presented, along with encouraging performance data obtained using four model species that are thermolabile or not sublimable. The test panel comprises two small organic compounds, a small and very large protein, and a large DNA species covering a 4-log mass range up to 1.7 MDa as part of a broad spectrum of analyte species evaluated to date. Three designs of innovative ion guides, a novel digital mass-selective quadrupole (dQMF), and a standard electrospray ionization (ESI) source are combined to an integrated device, abbreviated electrospray controlled ion-beam deposition (ES-CIBD). Full control is achieved by (i) the square-wave-driven radiofrequency (RF) ion guides with steadily tunable frequencies, including a dQMF allowing for investigation, purification, and deposition of a virtually unlimited m/z range, (ii) the adjustable landing energy of ions down to ∼2 eV/z enabling integrity-preserving soft landing, (iii) the deposition in UHV with high ion beam intensity (up to 3 nA) limiting contaminations and deposition time, and (iv) direct coverage control via the deposited charge. The maximum resolution of R = 650 and overall efficiency up to Ttotal = 4.4% calculated from the solution to UHV deposition are advantageous, whereby the latter can be further enhanced by optimizing ionization performance. In the setup presented, a scanning tunneling microscope (STM) is attached for in situ UHV investigations of deposited species, demonstrating a selective, structure-preserving process and atomically clean layers.
Collapse
Affiliation(s)
- Andreas Walz
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Karolina Stoiber
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Annette Huettig
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Hartmut Schlichting
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Johannes V Barth
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| |
Collapse
|
10
|
Dugan LD, Bier ME. Mechanospray Ionization MS of Proteins Including in the Folded State and Polymers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:772-782. [PMID: 35420806 DOI: 10.1021/jasms.1c00344] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mechanospray ionization (MoSI) is a technique that produces ions directly from solution-like electrospray ionization (ESI) but without the need of a high voltage. In MoSI, mechanical vibrations aerosolize solution phase analytes, whereby the resulting microdroplets can be directed into the inlet orifice of a mass spectrometer. In this work, MoSI is applied to biomolecules up to 80 kDa in mass in both denatured and native conditions as well as polymers up to 12 kDa in mass. The various MoSI devices used in these analyses were all comprised of a piezoelectric annulus attached to a central metallic disk containing an array of 4 to 7 μm diameter holes. The devices vibrated in the 100-170 kHz range to generate a beam of microdroplets that ultimately resulted in ion formation. A linear quadrupole ion trap (LIT) and orbitrap mass spectrometer were used in the analysis to investigate higher mass proteins at both native (folded) and denatured (unfolded) conditions. MoSI native mass spectra of proteins acquired on the orbitrap and LIT instrument demonstrated that proteins could remain intact and in a folded state. In the case of native MS of holomyoglobin, the intact folded protein remained mostly bound noncovalently to the heme group, and typically, the spectra showed reduced loss of the heme group by MoSI as compared to ESI. In both non-native and native protein analyses examples, broader often multimodal distributions to lower charge states were observed. When using the LIT instrument, a significant increase in the relative abundance of dimers was observed by MoSI as compared to ESI. The softness of the MoSI technique was evidenced by the lack of fragmentation, the formation of dimers as also noted by others ( J. Mass Spectrom. 2016, 424-429) and under native conditions, the retention of proteins in one or more presumed folded structures and for holomyoglobin the high retention of the heme group. When analyzing polyethylene glycol (PEG) and polypropylene glycol (PPG), MoSI also generated a broader distribution to lower charge states than ESI. By using the improved separation of peaks at lower charge states and all the charge states available, MoSI data should provide an improved ionization method to obtain more accurate mass and dispersity values for some polymers.
Collapse
Affiliation(s)
- Liam D Dugan
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Mark E Bier
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
11
|
Kumar D, Gautam N, Alnouti Y. Analyte recovery in LC-MS/MS bioanalysis: An old issue revisited. Anal Chim Acta 2022; 1198:339512. [PMID: 35190119 PMCID: PMC8864627 DOI: 10.1016/j.aca.2022.339512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/04/2022] [Accepted: 01/15/2022] [Indexed: 11/24/2022]
Abstract
There are several challenges associated with LC-MS/MS bioanalytical method development and validation. Low and variable recovery of some analytes, especially the more hydrophobic ones, is often challenging. Analytes can be lost to various extents throughout the process of sample collection, storage, before, during, and/or after sample preparation and analysis. The calculation of overall extraction recovery can detect problems of low recovery during sample preparation but does not identify the source(s) of analyte losses. Low overall analyte recovery is the net result of losses that can happen for multiple reasons at all steps of sample preparation and analysis. Therefore, identifying the source(s) of analyte loss during sample preparation can help guide the optimization the bioanalysis conditions to minimize these losses. In this article we propose a practical protocol to systematically identify and quantify the sources of low analyte recovery. This allows the proper choice of strategies to optimize the relevant bioanalytical conditions to minimize analyte losses and improve overall recovery.
Collapse
Affiliation(s)
- Devendra Kumar
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Nagsen Gautam
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Yazen Alnouti
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| |
Collapse
|
12
|
Płonka D, Kotuniak R, Dąbrowska K, Bal W. Electrospray-Induced Mass Spectrometry Is Not Suitable for Determination of Peptidic Cu(II) Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:2766-2776. [PMID: 34738801 PMCID: PMC8640992 DOI: 10.1021/jasms.1c00206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
The toolset of mass spectrometry (MS) is still expanding, and the number of metal ion complexes researched this way is growing. The Cu(II) ion forms particularly strong peptide complexes of biological interest which are frequent objects of MS studies, but quantitative aspects of some reported results are at odds with those of experiments performed in solution. Cu(II) complexes are usually characterized by fast ligand exchange rates, despite their high affinity, and we speculated that such kinetic lability could be responsible for the observed discrepancies. In order to resolve this issue, we selected peptides belonging to the ATCUN family characterized with high and thoroughly determined Cu(II) binding constants and re-estimated them using two ESI-MS techniques: standard conditions in combination with serial dilution experiments and very mild conditions for competition experiments. The sample acidification, which accompanies the electrospray formation, was simulated with the pH-jump stopped-flow technique. Our results indicate that ESI-MS should not be used for quantitative studies of Cu(II)-peptide complexes because the electrospray formation process compromises the entropic contribution to the complex stability, yielding underestimations of complex stability constants.
Collapse
|
13
|
Aliyari E, Konermann L. Atomistic Insights into the Formation of Nonspecific Protein Complexes during Electrospray Ionization. Anal Chem 2021; 93:12748-12757. [PMID: 34494821 DOI: 10.1021/acs.analchem.1c02836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Native electrospray ionization (ESI)-mass spectrometry (MS) is widely used for the detection and characterization of multi-protein complexes. A well-known problem with this approach is the possible occurrence of nonspecific protein clustering in the ESI plume. This effect can distort the results of binding affinity measurements, and it can even generate gas-phase complexes from proteins that are strictly monomeric in bulk solution. By combining experiments and molecular dynamics (MD) simulations, the current work for the first time provides detailed insights into the ESI clustering of proteins. Using ubiquitin as a model system, we demonstrate how the entrapment of more than one protein molecule in an ESI droplet can generate nonspecific clusters (e.g., dimers or trimers) via solvent evaporation to dryness. These events are in line with earlier proposals, according to which protein clustering is associated with the charged residue model (CRM). MD simulations on cytochrome c (which carries a large intrinsic positive charge) confirmed the viability of this CRM avenue. In addition, the cytochrome c data uncovered an alternative mechanism where protein-protein contacts were formed early within ESI droplets, followed by cluster ejection from the droplet surface. This second pathway is consistent with the ion evaporation model (IEM). The observation of these IEM events for large protein clusters is unexpected because the IEM has been thought to be associated primarily with low-molecular-weight analytes. In all cases, our MD simulations produced protein clusters that were stabilized by intermolecular salt bridges. The MD-generated charge states agreed with experiments. Overall, this work reveals that ESI-induced protein clustering does not follow a tightly orchestrated pathway but can proceed along different avenues.
Collapse
Affiliation(s)
- Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
14
|
Raab SA, El-Baba TJ, Laganowsky A, Russell DH, Valentine SJ, Clemmer DE. Protons Are Fast and Smart; Proteins Are Slow and Dumb: On the Relationship of Electrospray Ionization Charge States and Conformations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1553-1561. [PMID: 34151568 PMCID: PMC9003666 DOI: 10.1021/jasms.1c00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present simple considerations of how differences in time scales of motions of protons, the lightest and fastest chemical moiety, and the much longer time scales associated with the dynamics of proteins, among the heaviest and slowest analytes, may allow many protein conformations from solution to be kinetically trapped during the process of electrospraying protein solutions into the gas phase. In solution, the quantum nature of protons leads them to change locations by tunneling, an instantaneous process; moreover, the Grotthuss mechanism suggests that these small particles can respond nearly instantaneously to the dynamic motions of proteins that occur on much longer time scales. A conformational change is accompanied by favorable or unfavorable variations in the free energy of the system, providing the impetus for solvent ↔ protein proton exchange. Thus, as thermal distributions of protein conformations interconvert, protonation states rapidly respond, as specific acidic and basic sites are exposed or protected. In the vacuum of the mass spectrometer, protons become immobilized in locations that are specific to the protein conformations from which they were incorporated. In this way, conformational states from solution are preserved upon electrospraying them into the gas phase. These ideas are consistent with the exquisite sensitivity of electrospray mass spectra to small changes of the local environment that alter protein structure in solution. We might remember this approximation for the protonation of proteins in solution with the colloquial expression-protons are fast and smart; proteins are slow and dumb.
Collapse
Affiliation(s)
- Shannon A Raab
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Tarick J El-Baba
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - David E Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| |
Collapse
|
15
|
Markert C, Thinius M, Lehmann L, Heintz C, Stappert F, Wissdorf W, Kersten H, Benter T, Schneider BB, Covey TR. Observation of charged droplets from electrospray ionization (ESI) plumes in API mass spectrometers. Anal Bioanal Chem 2021; 413:5587-5600. [PMID: 34215914 PMCID: PMC8410725 DOI: 10.1007/s00216-021-03452-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/11/2021] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
Electrospray ionization (ESI) generates bare analyte ions from charged droplets, which result from spraying a liquid in a strong electric field. Experimental observations available in the literature suggest that at least a significant fraction of the initially generated droplets remain large, have long lifetimes, and can thus aspirate into the inlet system of an atmospheric pressure ionization mass spectrometer (API-MS). We report on the observation of fragment signatures from charged droplets penetrating deeply the vacuum stages of three commercial mass spectrometer systems with largely different ion source and spray configurations. Charged droplets can pass through the ion source and pressure reduction stages and even into the mass analyzer region. Since droplet signatures were found in all investigated instruments, the incorporation of charged droplets is considered a general phenomenon occurring with common spray conditions in ESI sources.
Collapse
Affiliation(s)
- Clara Markert
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Marco Thinius
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Laura Lehmann
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Chris Heintz
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Florian Stappert
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Walter Wissdorf
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany.
| | - Hendrik Kersten
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | - Thorsten Benter
- Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany
| | | | - Thomas R Covey
- SCIEX, 71 Four Valley Drive, Concord, ON, L4K 4V8, Canada
| |
Collapse
|
16
|
Otsuka Y. Direct Liquid Extraction and Ionization Techniques for Understanding Multimolecular Environments in Biological Systems (Secondary Publication). Mass Spectrom (Tokyo) 2021; 10:A0095. [PMID: 34249586 PMCID: PMC8246329 DOI: 10.5702/massspectrometry.a0095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 11/23/2022] Open
Abstract
A combination of direct liquid extraction using a small volume of solvent and electrospray ionization allows the rapid measurement of complex chemical components in biological samples and visualization of their distribution in tissue sections. This review describes the development of such techniques and their application to biological research since the first reports in the early 2000s. An overview of electrospray ionization, ion suppression in samples, and the acceleration of specific chemical reactions in charged droplets is also presented. Potential future applications for visualizing multimolecular environments in biological systems are discussed.
Collapse
Affiliation(s)
- Yoichi Otsuka
- Graduate School of Science, Osaka University, 1–1 Machikaneyama-cho, Toyonaka, Osaka 560–0043, Japan
- JST, PRESTO, 4–1–8 Honcho, Kawaguchi, Saitama 332–0012, Japan
| |
Collapse
|
17
|
Li X, Attanayake K, Valentine, Li P. Vibrating Sharp-edge Spray Ionization (VSSI) for voltage-free direct analysis of samples using mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35 Suppl 1:e8232. [PMID: 29993155 PMCID: PMC6529299 DOI: 10.1002/rcm.8232] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 10/14/2023]
Abstract
RATIONALE The development of miniaturized and field portable mass spectrometers could not succeed without a simple, compact, and robust ionization source. Here we present a voltage-free ionization method, Vibrating Sharp-edge Spray Ionization (VSSI), which can generate a spray of liquid samples using only one standard microscope glass slide to which a piezoelectric transducer is attached. Compared with existing ambient ionization methods, VSSI eliminates the need for a high electric field (~5000 V·cm-1 ) for spray generation, while sharing a similar level of simplicity and flexibility with the simplest direct ionization techniques currently available such as paper spray ionization (PSI) and other solid substrate-based electrospray ionization methods. METHODS The VSSI device was fabricated by attaching a piezoelectric transducer onto a standard glass microscope slide using epoxy glue. Liquid sample was aerosolized by either placing a droplet onto the vibrating edge of the glass slide or touching a wet surface with the glass edge. Mass spectrometric detection was achieved by placing the VSSI device 0.5-1 cm from the inlet of the mass spectrometer (Q-Exactive, ThermoScientific). RESULTS VSSI is demonstrated to ionize a diverse array of chemical species, including small organic molecules, carbohydrates, peptides, proteins, and nucleic acids. Preliminary sensitivity experiments show that high-quality mass spectra of acetaminophen can be obtained by consuming 100 femtomoles of the target. The dual spray of VSSI was also demonstrated by performing in-droplet denaturation of ubiquitin. Finally, due to the voltage-free nature and the direct-contact working mode of VSSI, it has been successfully applied for the detection of chemicals directly from human fingertips. CONCLUSIONS Overall, we report a compact ionization method based on vibrating sharp-edges. The simplicity and voltage-free nature of VSSI make it an attractive option for field portable applications or analyzing biological samples that are sensitive to high voltage or difficult to access by conventional ionization methods.
Collapse
Affiliation(s)
- Xiaojun Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Kushani Attanayake
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA
| |
Collapse
|
18
|
Prabhu GRD, Ponnusamy VK, Witek HA, Urban PL. Sample Flow Rate Scan in Electrospray Ionization Mass Spectrometry Reveals Alterations in Protein Charge State Distribution. Anal Chem 2020; 92:13042-13049. [PMID: 32893617 DOI: 10.1021/acs.analchem.0c01945] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sample flow rate is one of the parameters that influence the sensitivity of electrospray ionization (ESI) mass spectrometry. By varying the sample flow rate, initial droplets of different sizes can be generated. Protein molecules in small droplets may form gas-phase ions earlier than the ones in large droplets. Here, we have systematically studied the influence of sample flow rate on the ESI charge state distributions (CSDs) of model proteins. A dedicated programmable sample flow rate scanner was used to infuse protein samples at different flow rates into a mass spectrometer. The synergistic influence of sample flow rate and various electrolytes (ammonium acetate, ammonium bicarbonate, ammonium formate, and piperidine) was studied. Significant alterations to the CSDs with increasing flow rate were observed. For example, in the presence of ammonium acetate, at low flow rates, lower charge states of proteins showed high intensities, while at high flow rates, ions related to higher charge states of proteins dominated the spectra. On the other hand, in the presence of piperidine, a significant reduction in the ion currents of all charge states was observed during the flow rate scan. Our observations suggest that at low flow rates the protein molecules follow a charged residue model of ionization mechanism, and at high flow rates-due to structural changes in protein molecules in large ESI droplets-the charged residue and chain ejection models can possibly coexist. We propose the use of sample flow rate scan as a way to reveal the influence of flow rate on the CSDs of the studied proteins.
Collapse
Affiliation(s)
- Gurpur Rakesh D Prabhu
- Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan.,Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Vinoth Kumar Ponnusamy
- Department of Medicinal and Applied Chemistry & Research Center for Environmental Medicine, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan
| | - Henryk A Witek
- Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan.,Center for Emergent Functional Matter Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
| | - Pawel L Urban
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.,Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| |
Collapse
|
19
|
Aliyari E, Konermann L. Formation of Gaseous Proteins via the Ion Evaporation Model (IEM) in Electrospray Mass Spectrometry. Anal Chem 2020; 92:10807-10814. [DOI: 10.1021/acs.analchem.0c02290] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
20
|
Prantl E, Kohl B, Ryvlin D, Biegger P, Wadepohl H, Rominger F, Bunz UHF, Mastalerz M, Waldvogel SR. Microporous Triptycene-Based Affinity Materials on Quartz Crystal Microbalances for Tracing of Illicit Compounds. Chempluschem 2020; 84:1239-1244. [PMID: 31944043 DOI: 10.1002/cplu.201900189] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/09/2019] [Indexed: 12/20/2022]
Abstract
Triptycene-based organic molecules of intrinsic microporosity (OMIMs) with extended functionalized π-surfaces are excellent materials for gas sorption and separation. In this study, the affinities of triptycene-based OMIM affinity materials on 195 MHz high-fundamental-frequency quartz crystal microbalances (HFF-QCMs) for hazardous and illicit compounds such as piperonal and (-)-norephedrine were determined. Both new and existing porous triptycene-based affinity materials were investigated, resulting in very high sensitivities and selectivities that could be applied for sensing purposes. Remarkable results were found for safrole - a starting material for illicit compounds such as ecstasy. A systematic approach highlights the effects of different size of π-surfaces of these affinity materials, allowing a classification of the properties that might be optimal for the design of future OMIM-based affinity materials.
Collapse
Affiliation(s)
- Ephraim Prantl
- Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Bernd Kohl
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Dimitrij Ryvlin
- Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Philipp Biegger
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 271, 69120, Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Uwe H F Bunz
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Michael Mastalerz
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Siegfried R Waldvogel
- Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| |
Collapse
|
21
|
Recent advances in mass spectrometry studies of non-covalent complexes of macrocycles - A review. Anal Chim Acta 2019; 1081:32-50. [DOI: 10.1016/j.aca.2019.06.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/29/2022]
|
22
|
Non-targeted mercapturic acid screening in urine using LC-MS/MS with matrix effect compensation by postcolumn infusion of internal standard (PCI-IS). Anal Bioanal Chem 2019; 411:7771-7781. [DOI: 10.1007/s00216-019-02166-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/11/2019] [Accepted: 09/23/2019] [Indexed: 11/25/2022]
|
23
|
Hung HM, Hsu MN, Hoffmann MR. Quantification of SO 2 Oxidation on Interfacial Surfaces of Acidic Micro-Droplets: Implication for Ambient Sulfate Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:9079-9086. [PMID: 30040406 DOI: 10.1021/acs.est.8b01391] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Sulfate formation on the surface of aqueous microdroplets was investigated using a spray-chamber reactor coupled to an electrospray ionization mass spectrometer that was calibrated using Na2SO4(aq) as a function of pH. The observed formation of SO3-•, SO4-•, and HSO4- at pH < 3.5 without the addition of other oxidants indicates that an efficient oxidation pathway takes place involving direct interfacial electron transfer from SO2 to O2 on the surface of aqueous microdroplets. Compared to the well-studied sulfate formation kinetics via oxidation by H2O2(aq), the interfacial SO42- formation rate on the surface of microdroplets was estimated to be proportional to the collision frequency of SO2 with a pH-dependent efficiency factor of 5.6 × 10-5[H+]3.7/([H+]3.7+10-13.5). The rate via the acidic surface reactions is approximately 1-2 orders of magnitude higher than that by H2O2(aq) for a 1.0 ppbv concentration of H2O2( g) interacting with 50 μg/m3 of aerosols. This finding highlights the relative importance of the interfacial SO2 oxidation in the atmosphere. Chemical reactions on the aquated aerosol surfaces are overlooked in most atmospheric chemistry models. This interfacial reaction pathway may help to explain the observed rapid conversion of SO2 to sulfate in mega-cities and nearby regions with high PM2.5 haze aerosol loadings.
Collapse
Affiliation(s)
- Hui-Ming Hung
- Department of Atmospheric Sciences , National Taiwan University No. 1 , Sec. 4, Roosevelt Road , Taipei 10617 Taiwan
| | - Mu-Ni Hsu
- National Chung-Shan Institute of Science & Technology , Taoyuan City 32557 , Taiwan
| | - Michael R Hoffmann
- Linde Center for Global Environmental Science , California Institute of Technology Linde-Robinson Laboratory Pasadena , California 91125 , United States
| |
Collapse
|
24
|
Longhi G, Ceselli A, Fornili SL, Turco Liveri V. Molecular dynamics and metadynamics simulations of electrosprayed water nanodroplets including sodium bis(2-ethylhexyl)sulfosuccinate micelles. J Chem Phys 2018; 146:204305. [PMID: 28571388 DOI: 10.1063/1.4984038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) under conditions of electrospray ionization (ESI) has been investigated by molecular dynamics (MD) and well-tempered metadynamics (WTM) simulations at 300 K and 400 K. We have examined water droplets with initial fixed numbers of water molecules (1000) and AOT- anions (100), and with sodium cations in the range of 70-130. At 300 K, all charged droplets show the water evaporation rate increasing with the absolute value of the initial droplet charge state (Z), accompanied by ejection of an increasing number of solvated sodium ions or by expulsion of AOT- anions depending on the sign of Z and by fragmentation in the case of high |Z|. At 400 K, the water evaporation becomes more rapid and the fission process more extensive. In all cases, the AOTNa molecules, arranged as a direct micelle inside the aqueous system, undergo a rapid inversion in vacuo so that the hydrophilic heads and sodium ions surrounded by water molecules move toward the droplet interior. At the end of the 100-ns MD simulations, some water molecules remain within the aggregates at both temperatures. The subsequent metadynamics simulations accelerate the droplet evolution and show that all systems become anhydrous, in agreement with the experimental results of ESI mass spectrometry. This complete water loss is accompanied by sodium counterion emission for positively charged aggregates at 300 K. The analysis shows how the temperature and droplet charge state affect the populations of the generated surfactant aggregates, providing information potentially useful in designing future ESI experimental conditions.
Collapse
Affiliation(s)
- Giovanna Longhi
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Alberto Ceselli
- Dipartimento di Informatica, Università di Milano, Via Bramante 65, 26013 Crema, Cremona, Italy
| | - Sandro L Fornili
- Dipartimento di Informatica, Università di Milano, Via Bramante 65, 26013 Crema, Cremona, Italy
| | - Vincenzo Turco Liveri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche "STEBICEF," Università degli Studi di Palermo, Viale delle Scienze I, 90128 Palermo, Italy
| |
Collapse
|
25
|
Weske S, Hardin RA, Auth T, O'Hair RAJ, Koszinowski K, Ogle CA. Argentate(i) and (iii) complexes as intermediates in silver-mediated cross-coupling reactions. Chem Commun (Camb) 2018; 54:5086-5089. [PMID: 29708564 DOI: 10.1039/c8cc01707g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite the potential of silver to mediate synthetically valuable cross-coupling reactions, the operating mechanisms have remained unknown. Here, we use a combination of rapid-injection NMR spectroscopy, electrospray-ionization mass spectrometry, and quantum chemical calculations to demonstrate that these transformations involve argentate(i) and (iii) complexes as key intermediates.
Collapse
Affiliation(s)
- Sebastian Weske
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany.
| | | | | | | | | | | |
Collapse
|
26
|
Raymond O, Henderson W, Brothers PJ, Plieger PG. Electrospray Ionisation Mass Spectrometric (ESI MS) Screening and Characterisation of Beryllium Complexes with Potentially Encapsulating Aminopolycarboxylate and Related Ligands. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701435] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Onyekachi Raymond
- Chemistry, School of Science; University of Waikato; Private Bag 3105 Hamilton New Zealand
| | - William Henderson
- Chemistry, School of Science; University of Waikato; Private Bag 3105 Hamilton New Zealand
| | | | - Paul G. Plieger
- Institute of Fundamental Sciences; Massey University; Private Bag 11222 4410 Palmerston North New Zealand
| |
Collapse
|
27
|
Hollerbach A, Logsdon D, Iyer K, Li A, Schaber JA, Graham Cooks R. Sizing sub-diffraction limit electrosprayed droplets by structured illumination microscopy. Analyst 2018; 143:232-240. [PMID: 29138765 DOI: 10.1039/c7an01278k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Electrosprayed droplets are widely studied for their role in the formation of ions at atmospheric pressure.
Collapse
Affiliation(s)
| | - David Logsdon
- Chemistry Department
- Purdue University
- West Lafayette
- USA
| | - Kiran Iyer
- Chemistry Department
- Purdue University
- West Lafayette
- USA
| | - Anyin Li
- Chemistry Department
- Purdue University
- West Lafayette
- USA
| | - J. Andy Schaber
- Bioscience Imaging Facility
- Bindley Bioscience Center
- Purdue University
- West Lafayette
- USA
| | | |
Collapse
|
28
|
Liigand P, Heering Suu A, Kaupmees K, Leito I, Girod M, Antoine R, Kruve A. The Evolution of Electrospray Generated Droplets is Not Affected by Ionization Mode. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2124-2131. [PMID: 28744770 DOI: 10.1007/s13361-017-1737-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/22/2017] [Accepted: 06/11/2017] [Indexed: 06/07/2023]
Abstract
Ionization efficiency and mechanism in ESI is strongly affected by the properties of mobile phase. The use of mobile-phase properties to accurately describe droplets in ESI source is convenient but may be inadequate as the composition of the droplets is changing in the plume due to electrochemical reactions occurring in the needle tip as well as continuous drying and fission of droplets. Presently, there is paucity of research on the effect of the polarity of the ESI mode on mobile phase composition in the droplets. In this paper, the change in the organic solvent content, pH, and droplet size are studied in the ESI plume in both ESI+ and ESI- ionization mode. We introduce a rigorous way - the absolute pH (pHabsH2O) - to describe pH change in the plume that takes into account organic solvent content in the mobile phase. pHabsH2O enables comparing acidities of ESI droplets with different organic solvent contents. The results are surprisingly similar for both ionization modes, indicating that the dynamics of the change of mobile-phase properties is independent from the ESI mode used. This allows us to conclude that the evolution of ESI droplets first of all proceeds via the evaporation of the organic modifier and to a lesser extent via fission of smaller droplets from parent droplets. Secondly, our study shows that qualitative findings related to the ESI process obtained on the ESI+ mode can almost directly be applied also in the ESI- mode. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Piia Liigand
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
| | - Agnes Heering Suu
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Karl Kaupmees
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Ivo Leito
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Marion Girod
- CNRS, Université Claude Bernard Lyon 1, Ens de Lyon, Institut des Sciences Analytiques, University of Lyon, UMR 5280, 5 rue de la Doua, F-69100, Villeurbanne, France
| | - Rodolphe Antoine
- Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, University of Lyon, UMR 5306, F-69622, Lyon, France
| | - Anneli Kruve
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 3200008, Israel
| |
Collapse
|
29
|
Konermann L. Addressing a Common Misconception: Ammonium Acetate as Neutral pH "Buffer" for Native Electrospray Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1827-1835. [PMID: 28710594 DOI: 10.1007/s13361-017-1739-3] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/14/2017] [Accepted: 06/15/2017] [Indexed: 05/12/2023]
Abstract
Native ESI-MS involves the transfer of intact proteins and biomolecular complexes from solution into the gas phase. One potential pitfall is the occurrence of pH-induced changes that can affect the analyte while it is still surrounded by solvent. Most native ESI-MS studies employ neutral aqueous ammonium acetate solutions. It is a widely perpetuated misconception that ammonium acetate buffers the analyte solution at neutral pH. By definition, a buffer consists of a weak acid and its conjugate weak base. The buffering range covers the weak acid pKa ± 1 pH unit. NH4+ and CH3-COO- are not a conjugate acid/base pair, which means that they do not constitute a buffer at pH 7. Dissolution of ammonium acetate salt in water results in pH 7, but this pH is highly labile. Ammonium acetate does provide buffering around pH 4.75 (the pKa of acetic acid) and around pH 9.25 (the pKa of ammonium). This implies that neutral ammonium acetate solutions electrosprayed in positive ion mode will likely undergo acidification down to pH 4.75 ± 1 in the ESI plume. Ammonium acetate nonetheless remains a useful additive for native ESI-MS. It is a volatile electrolyte that can mimic the solvation properties experienced by proteins under physiological conditions. Also, a drop from pH 7 to around pH 4.75 is less dramatic than the acidification that would take place in pure water. It is hoped that the habit of referring to pH 7 solutions as ammonium acetate "buffer" will disappear from the literature. Ammonium acetate "solution" should be used instead. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, ON, N6A 5B7, Canada.
| |
Collapse
|
30
|
Consta S, Sharawy M, Oh MI, Malevanets A. Advances in Modeling the Stability of Noncovalent Complexes in Charged Droplets with Applications in Electrospray Ionization-MS Experiments. Anal Chem 2017; 89:8192-8202. [DOI: 10.1021/acs.analchem.7b01941] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Styliani Consta
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Mahmoud Sharawy
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Myong In Oh
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Anatoly Malevanets
- Department
of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario N6A 5B9, Canada
| |
Collapse
|
31
|
Bain RM, Ayrton ST, Cooks RG. Fischer Indole Synthesis in the Gas Phase, the Solution Phase, and at the Electrospray Droplet Interface. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1359-1364. [PMID: 28194736 DOI: 10.1007/s13361-017-1597-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/06/2017] [Accepted: 01/07/2017] [Indexed: 06/06/2023]
Abstract
Previous reports have shown that reactions occurring in the microdroplets formed during electrospray ionization can, under the right conditions, exhibit significantly greater rates than the corresponding bulk solution-phase reactions. The observed acceleration under electrospray ionization could result from a solution-phase, a gas-phase, or an interfacial reaction. This study shows that a gas-phase ion/molecule (or ion/ion) reaction is not responsible for the observed rate enhancement in the particular case of the Fischer indole synthesis. The results show that the accelerated reaction proceeds in the microdroplets, and evidence is provided that an interfacial process is involved. Graphical Abstract <!-- [INSERT GRAPHICAL ABSTRACT TEXT HERE] -->.
Collapse
Affiliation(s)
- Ryan M Bain
- 560 Oval Drive Department of Chemistry and the Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA
| | - Stephen T Ayrton
- 560 Oval Drive Department of Chemistry and the Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- 560 Oval Drive Department of Chemistry and the Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA.
| |
Collapse
|
32
|
Liigand P, Kaupmees K, Haav K, Liigand J, Leito I, Girod M, Antoine R, Kruve A. Think Negative: Finding the Best Electrospray Ionization/MS Mode for Your Analyte. Anal Chem 2017; 89:5665-5668. [DOI: 10.1021/acs.analchem.7b00096] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Piia Liigand
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Karl Kaupmees
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Kristjan Haav
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Jaanus Liigand
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Ivo Leito
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Marion Girod
- Univ Lyon,
CNRS,
Université Claude Bernard Lyon 1, Ens de Lyon, Institut des
Sciences Analytiques, UMR 5280, 5 rue
de la Doua, F-69100, Villeurbanne, France
| | - Rodolphe Antoine
- Univ Lyon, Université
Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR 5306, F-69622, Lyon, France
| | - Anneli Kruve
- Institute
of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
- Schulich
Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| |
Collapse
|
33
|
Ido Y, Kobara H, Tominaga KI, Wakisaka A. A Reactor System Using Electrospray in the Liquid Phase and Its Application in Selective Cyclosiloxane Synthesis. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.6b04774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yohei Ido
- National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Hitomi Kobara
- National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Ken-ichi Tominaga
- National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Akihiro Wakisaka
- National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| |
Collapse
|
34
|
Koszinowski K, Lissy F. ESI activity of Br⁻, BF₄⁻ , ClO₄⁻ and BPh₄⁻ anions in the presence of Li⁺ and NBu⁴⁺ counter-ions. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:144-151. [PMID: 28098404 DOI: 10.1002/jms.3911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/12/2017] [Accepted: 01/14/2017] [Indexed: 06/06/2023]
Abstract
To improve our understanding of the electrospray ionization (ESI) process, we have subjected equimolar mixtures of salts A+ X- (A+ = Li+ , NBu4+ ; X- = Br- , ClO4- , BF4- , BPh4- ) in different solvents (CH3 CN, tetrahydrofuran, CH3 OH, H2 O) to negative-ion mode ESI and analyzed the relative ESI activity of the different anionic model analytes. The ESI activity of the large and hydrophobic BPh4- ion greatly exceeds that of the smaller and more hydrophilic anions Br- , ClO4- and BF4- , which we ascribe to its higher surface activity. Moreover, the ESI activity of the anions is modulated by the action of the counter-ions and their different tendency toward ion pairing. The tendency toward ion pairing can be reduced by the addition of the chelating ligands 12-crown-4 and 2.2.1 cryptand and is, although to a smaller degree, further influenced by the variation of the solvent. Complementary electrical conductivity measurements afford additional information on the interactions of the ionic constituents of the sample solutions. Copyright © 2017 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- K Koszinowski
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstr. 2, 37077, Göttingen, Germany
| | - F Lissy
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstr. 2, 37077, Göttingen, Germany
| |
Collapse
|
35
|
Ingram AJ, Boeser CL, Zare RN. Going beyond electrospray: mass spectrometric studies of chemical reactions in and on liquids. Chem Sci 2016; 7:39-55. [PMID: 28757996 PMCID: PMC5508663 DOI: 10.1039/c5sc02740c] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/01/2015] [Indexed: 12/16/2022] Open
Abstract
There has been a burst in the number and variety of available ionization techniques to use mass spectrometry to monitor chemical reactions in and on liquids. Chemists have gained the capability to access chemistry at unprecedented timescales, and monitor reactions and detect intermediates under almost any set of conditions. Herein, recently developed ionization techniques that facilitate mechanistic studies of chemical processes are reviewed. This is followed by a discussion of our perspective on the judicious application of these and similar techniques in order to study reaction mechanisms.
Collapse
Affiliation(s)
- Andrew J Ingram
- Department of Chemistry , Stanford University , Stanford , CA 94305 , USA .
| | | | - Richard N Zare
- Department of Chemistry , Stanford University , Stanford , CA 94305 , USA .
| |
Collapse
|
36
|
Soleilhac A, Dagany X, Dugourd P, Girod M, Antoine R. Correlating Droplet Size with Temperature Changes in Electrospray Source by Optical Methods. Anal Chem 2015; 87:8210-7. [DOI: 10.1021/acs.analchem.5b00976] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Antonin Soleilhac
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon, 69622 CEDEX Villeurbanne, France
| | - Xavier Dagany
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon, 69622 CEDEX Villeurbanne, France
| | - Philippe Dugourd
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon, 69622 CEDEX Villeurbanne, France
| | - Marion Girod
- Institut
des Sciences Analytiques, UMR 5280 CNRS Université Lyon1, Université de Lyon, 69622 CEDEX Villeurbanne, France
| | - Rodolphe Antoine
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon, 69622 CEDEX Villeurbanne, France
| |
Collapse
|
37
|
Koch W, Forcisi S, Lehmann R, Schmitt-Kopplin P. Sensitivity improvement in hydrophilic interaction chromatography negative mode electrospray ionization mass spectrometry using 2-(2-methoxyethoxy)ethanol as a post-column modifier for non-targeted metabolomics. J Chromatogr A 2014; 1361:209-16. [PMID: 25160955 DOI: 10.1016/j.chroma.2014.07.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 11/19/2022]
Abstract
The application of ammonia acetate buffered liquid chromatography (LC) eluents is known to concomitantly lead to ion suppression when electrospray ionization mass spectrometry (ESI-MS) detection is used. In negative ESI mode, post column infusion of 2-(2-methoxyethoxy)ethanol (2-MEE) was shown in the literature to help to compensate this adverse effect occurring in reversed phase liquid chromatography mass spectrometry (RP-LC-MS) analyses. Here a setup of direct infusion and hydrophilic interaction chromatography (HILIC) post-column infusion experiments was established in order to investigate systematically the beneficial effects of 2-MEE. We demonstrate that, 2-MEE can help to improve ESI-MS sensitivity in HILIC too and reveal analyte structure specific behaviors. Our study indicates that 2-MEE especially improves ESI response for small and polar molecules. The ESI response of stable isotope labeled amino acids spiked into biological matrices increases up to 50-fold (i.e. D5-l-glutamic acid) when post column infusion of 2-MEE is applied. A non-targeted analysis of a pooled urine sample via HILIC-ESI-QTOF-MS supports this hypothesis. In direct infusion, the combined application of an ammonia acetate buffered solution together with 2-MEE results in an improved ESI response compared to a non-buffered solution. We observed up to 60-fold increased ESI response of l-lysine. We propose this effect is putatively caused by the formation of smaller ESI droplets and stripping of positive charge from ESI droplets due to evaporation of acetic acid anions. In summary, post-column infusion of 2-MEE especially enhances ESI response of small and polar molecules. Therefore it can be regarded as a valuable add-on in targeted or non-targeted metabolomic HILIC-MS studies since this method sets a focus on this molecule category.
Collapse
Affiliation(s)
- Wendelin Koch
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, German Research Center for Environment Health, Neuherberg D-85764, Germany; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan D-85354, Germany; German Center for Diabetes (DZD), Munchen, Germany.
| | - Sara Forcisi
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, German Research Center for Environment Health, Neuherberg D-85764, Germany; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan D-85354, Germany; German Center for Diabetes (DZD), Munchen, Germany
| | - Rainer Lehmann
- Division of Clinical Chemistry and Pathobiochemistry (Central Laboratory), University Hospital Tübingen, 72076 Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes (DZD), Munchen, Germany
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, German Research Center for Environment Health, Neuherberg D-85764, Germany; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan D-85354, Germany; German Center for Diabetes (DZD), Munchen, Germany.
| |
Collapse
|
38
|
Yue X, Vahidi S, Konermann L. Insights into the mechanism of protein electrospray ionization from salt adduction measurements. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1322-1331. [PMID: 24839193 DOI: 10.1007/s13361-014-0905-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/03/2014] [Indexed: 06/03/2023]
Abstract
The mechanisms whereby protein ions are liberated from charged droplets during electrospray ionization (ESI) remain under investigation. Compact conformers electrosprayed from aqueous solution in positive ion mode likely follow the charged residue model (CRM), which envisions analyte release after solvent evaporation to dryness. The concentration of nonvolatile salts such as NaCl increases sharply within vanishing CRM droplets, promoting nonspecific pairing of Cl(-) and Na(+) with charged groups on the protein surface. For unfolded proteins, it has been proposed that ion formation occurs via the chain ejection model (CEM). During the CEM proteins are expelled from the droplet long before complete solvent evaporation has taken place. Here we examine whether salt adduction levels support the view that folded and unfolded proteins follow different ESI mechanisms. Solvent evaporation during the CEM is expected to be less extensive and, hence, the salt concentration at the point of protein release should be substantially lower than for the CRM. CEM ions should therefore exhibit lower adduction levels than CRM species. We explore the adduction behavior of several proteins that were chosen to allow comparative studies on folded and unfolded structures in the same solution. In-source activation eliminates chloride adducts via HCl release, generating protein ions that are heterogeneously charged because of sodiation and protonation. Sodiation levels measured under such conditions provide estimates of the salt adduction behavior experienced by the "nascent" analyte ions. Sodiation levels are significantly reduced for unfolded proteins, supporting the view that these species are indeed formed via the CEM.
Collapse
Affiliation(s)
- Xuanfeng Yue
- Department of Chemistry, The University of Western Ontario, London, ON, N6A 5B7, Canada
| | | | | |
Collapse
|
39
|
Ingram AJ, Solis-Ibarra D, Zare RN, Waymouth RM. Trinuclear Pd₃O₂ intermediate in aerobic oxidation catalysis. Angew Chem Int Ed Engl 2014; 53:5648-52. [PMID: 24711099 DOI: 10.1002/anie.201400134] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/02/2014] [Indexed: 11/06/2022]
Abstract
The activation of O2 is a key step in selective catalytic aerobic oxidation reactions mediated by transition metals. The bridging trinuclear palladium species, [(LPd(II))3(μ(3)-O)2](2+) (L=2,9-dimethylphenanthroline), was identified during the [LPd(OAc)]2(OTf)2-catalyzed aerobic oxidation of 1,2-propanediol. Independent synthesis, structural characterization, and catalytic studies of the trinuclear compound show that it is a product of oxygen activation by reduced palladium species and is a competent intermediate in the catalytic aerobic oxidation of alcohols. The formation and catalytic activity of the trinuclear Pd3O2 species illuminates a multinuclear pathway for aerobic oxidation reactions catalyzed by Pd complexes.
Collapse
Affiliation(s)
- Andrew J Ingram
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, CA 94305-5080 (USA)
| | | | | | | |
Collapse
|
40
|
Ingram AJ, Solis-Ibarra D, Zare RN, Waymouth RM. Trinuclear Pd3O2Intermediate in Aerobic Oxidation Catalysis. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
41
|
Kostyukevich Y, Kononikhin A, Popov I, Nikolaev E. In-ESI Source Hydrogen/Deuterium Exchange of Carbohydrate Ions. Anal Chem 2014; 86:2595-600. [DOI: 10.1021/ac4038202] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yury Kostyukevich
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow
Region, Russia
| | - Alexey Kononikhin
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow
Region, Russia
| | - Igor Popov
- Emanuel
Institute for Biochemical Physics, Russian Academy of Sciences, Kosygina st. 4, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow
Region, Russia
| | - Eugene Nikolaev
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334 Moscow, Russia
- Emanuel
Institute for Biochemical Physics, Russian Academy of Sciences, Kosygina st. 4, 119334 Moscow, Russia
- Orekhovich
Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, ul. Pogodinskaya 10, 119121 Moscow, Russia
| |
Collapse
|
42
|
McDonald LW, Campbell JA, Clark SB. Failure of ESI Spectra to Represent Metal-Complex Solution Composition: A Study of Lanthanide–Carboxylate Complexes. Anal Chem 2014; 86:1023-9. [DOI: 10.1021/ac401751r] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luther W. McDonald
- Department
of Chemistry, Washington State University, Pullman, Washington 99164, United States
- Chemical
and Biological Signature Sciences Group, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - James A. Campbell
- Chemical
and Biological Signature Sciences Group, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Sue B. Clark
- Department
of Chemistry, Washington State University, Pullman, Washington 99164, United States
| |
Collapse
|
43
|
Stindt A, Warschat C, Bierstedt A, Panne U, Riedel J. Characterisation of an inexpensive sonic spray ionisation source using laser-induced fluorescence imaging and mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2014; 20:21-29. [PMID: 24881452 DOI: 10.1255/ejms.1242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A commercially available airbrush gun as a new source for spray ionisation is presented. It is best operated employing moderate stagnation pressures, resulting in a sonic gas flow. A mass spectrometric investigation on the amino acid Lysine and several peptides reveals that this inexpensive approach results in reproducible mass spectra. The ion patterns strongly resemble the results from other studies obtained with custom-made sonic spray vaporisers. The patterns also resemble the mass spectra recorded with electrospray devices. For a better understanding of the vaporisation process, the mass spectrometry experiments are accompanied by laser-induced fluorescence experiments. Inverse Abel Transform of the obtained fluorescence maps allows the determination of the full three-dimensional distribution of the spray cone. Furthermore, via exploitation of the solvatochromism of the used dye the solvation-state distribution can be visualised. In addition, expansion parameters, such as droplet size and velocity, are obtained by laser stroboscopy. The experiments demonstrate that the analyte hardly desolvates throughout the expansion. This indicates a subsequent vaporisation of the residual solvent in the intermediate pressure region of the mass spectrometer.
Collapse
|
44
|
Pauly M, Sroka M, Reiss J, Rinke G, Albarghash A, Vogelgesang R, Hahne H, Kuster B, Sesterhenn J, Kern K, Rauschenbach S. A hydrodynamically optimized nano-electrospray ionization source and vacuum interface. Analyst 2014; 139:1856-67. [DOI: 10.1039/c3an01836a] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
45
|
Barylyuk K, Gülbakan B, Xie X, Zenobi R. DNA oligonucleotides: a model system with tunable binding strength to study monomer-dimer equilibria with electrospray ionization-mass spectrometry. Anal Chem 2013; 85:11902-12. [PMID: 24274465 DOI: 10.1021/ac402669e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Electrospray ionization (ESI) is increasingly used to measure binding strengths, but it is not always clear whether the ESI process introduces artifacts. Here we propose a model monomer-dimer equilibrium system based on DNA oligonucleotides to systematically explore biomolecular self-association with the ESI-mass spectrometry (MS) titration method. The oligonucleotides are designed to be self-complementary and have the same chemical composition and mass, allowing for equal ionization probability, ion transmission, and detection efficiency in ESI-MS. The only difference is the binding strength, which is determined by the nucleotide sequence and can be tuned to cover a range of dissociation constant values. This experimental design allows one to focus on the impact of ESI on the chemical equilibrium and to avoid the other typical sources of variation in ESI-MS signal responses, which yields a direct comparison of samples with different binding strengths. For a set of seven model DNA oligonucleotides, the monomer-dimer binding equilibrium was probed with the ESI-MS titration method in both positive and negative ion modes. A mathematical model describing the dependence of the monomer-to-dimer peak intensity ratio on the DNA concentration was proposed and used to extract apparent Kd values and the fraction of DNA duplex that irreversibly dissociates in the gas phase. The Kd values determined via ESI-MS titration were compared to those determined in solution with isothermal titration calorimetry and equilibrium thermal denaturation methods and were found to be significantly lower. The observed discrepancy was attributed to a greater electrospray response of dimers relative to that of monomers.
Collapse
Affiliation(s)
- Konstantin Barylyuk
- Department of Chemistry and Applied Biosciences, ETH Zurich , Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
| | | | | | | |
Collapse
|
46
|
Malevanets A, Consta S. Variation of droplet acidity during evaporation. J Chem Phys 2013; 138:184312. [DOI: 10.1063/1.4804303] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
|
47
|
Bobbitt JM, Li L, Carlton DD, Yasin M, Bhawal S, Foss FW, Wernisch S, Pell R, Lindner W, Schug KA. Diastereoselective discrimination of lysine–alanine–alanine peptides by zwitterionic cinchona alkaloid-based chiral selectors using electrospray ionization mass spectrometry. J Chromatogr A 2012; 1269:308-15. [DOI: 10.1016/j.chroma.2012.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/27/2012] [Accepted: 08/03/2012] [Indexed: 11/15/2022]
|
48
|
Zhu W, Yuan Y, Zhou P, Zeng L, Wang H, Tang L, Guo B, Chen B. The expanding role of electrospray ionization mass spectrometry for probing reactive intermediates in solution. Molecules 2012; 17:11507-37. [PMID: 23018925 PMCID: PMC6268401 DOI: 10.3390/molecules171011507] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 08/29/2012] [Accepted: 09/05/2012] [Indexed: 12/31/2022] Open
Abstract
Within the past decade, electrospray ionization mass spectrometry (ESI-MS) has rapidly occupied a prominent position for liquid-phase mechanistic studies due to its intrinsic advantages allowing for efficient "fishing" (rapid, sensitive, specific and simultaneous detection/identification) of multiple intermediates and products directly from a "real-world" solution. In this review we attempt to offer a comprehensive overview of the ESI-MS-based methodologies and strategies developed up to date to study reactive species in reaction solutions. A full description of general issues involved with probing reacting species from complex (bio)chemical reaction systems is briefly covered, including the potential sources of reactive intermediate (metabolite) generation, analytical aspects and challenges, basic rudiments of ESI-MS and the state-of-the-art technology. The main purpose of the present review is to highlight the utility of ESI-MS and its expanding role in probing reactive intermediates from various reactions in solution, with special focus on current progress in ESI-MS-based approaches for improving throughput, testing reality and real-time detection by using newly developed MS instruments and emerging ionization sources (such as ambient ESI techniques). In addition, the limitations of modern ESI-MS in detecting intermediates in organic reactions is also discussed.
Collapse
Affiliation(s)
- Weitao Zhu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Yu Yuan
- School of Pharmaceutical Sciences, Central South University, 172 Tongzipo Road, Changsha 410013, China;
| | - Peng Zhou
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Le Zeng
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Hua Wang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Ling Tang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Bin Guo
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| | - Bo Chen
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, 36 Lushan Road, Changsha 410081, China; (W.Z.); (P.Z.); (L.Z.); (H.W.); (L.T.); (B.C.)
| |
Collapse
|
49
|
Gal JF, Iacobucci C, Monfardini I, Massi L, Duñach E, Olivero S. Metal triflates and triflimides as Lewis “superacids”: preparation, synthetic application and affinity tests by mass spectrometry. J PHYS ORG CHEM 2012. [DOI: 10.1002/poc.3019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Jean-François Gal
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| | - Claudio Iacobucci
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| | - Ilaria Monfardini
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| | - Lionel Massi
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| | - Elisabet Duñach
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| | - Sandra Olivero
- Institut de Chimie de Nice, UMR CNRS 7272; Université de Nice-Sophia Antipolis; 06108 NICE Cedex 2 France
| |
Collapse
|
50
|
Huang Y, Yoon SH, Heron SR, Masselon CD, Edgar JS, Tureček F, Goodlett DR. Surface acoustic wave nebulization produces ions with lower internal energy than electrospray ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1062-70. [PMID: 22476889 DOI: 10.1007/s13361-012-0352-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/20/2012] [Accepted: 01/22/2012] [Indexed: 05/22/2023]
Abstract
Surface acoustic wave nebulization (SAWN) has recently been reported as a novel method to transfer non-volatile analytes directly from solution to the gas phase for mass spectrometric analysis. Here we present a comparison of the survival yield of SAWN versus electrospray ionization (ESI) produced ions. A series of substituted benzylpyridinium (BzPy) compounds were utilized to measure ion survival yield from which ion energetics were inferred. We also estimated bond dissociation energies using higher level quantum chemical calculations than previously reported for BzPy ions. Additionally, the effects on BzPy precursor ion survival of SAWN operational parameters such as inlet capillary temperature and solution flow-rate were investigated. Under all conditions tested, SAWN-generated BzPy ions displayed a higher tendency for survival and thus have lower internal energies than those formed by ESI.
Collapse
Affiliation(s)
- Yue Huang
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
| | | | | | | | | | | | | |
Collapse
|