1
|
Creydt M, Fischer M. Food metabolomics: Latest hardware-developments for nontargeted food authenticity and food safety testing. Electrophoresis 2022; 43:2334-2350. [PMID: 36104152 DOI: 10.1002/elps.202200126] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/10/2022] [Accepted: 09/05/2022] [Indexed: 12/14/2022]
Abstract
The analytical requirements for food testing have increased significantly in recent years. On the one hand, because food fraud is becoming an ever-greater challenge worldwide, and on the other hand because food safety is often difficult to monitor due to the far-reaching trade chains. In addition, the expectations of consumers on the quality of food have increased, and they are demanding extensive information. Cutting-edge analytical methods are required to meet these demands. In this context, non-targeted metabolomics strategies using mass and nuclear magnetic resonance spectrometers (mass spectrometry [MS]) have proven to be very suitable. MS-based approaches are of particular importance as they provide a comparatively high analytical coverage of the metabolome. Accordingly, the efficiency to address even challenging issues is high. A variety of hardware developments, which are explained in this review, have contributed to these advances. In addition, the potential of future developments is highlighted, some of which are currently not yet commercially available or only used to a comparatively small extent but are expected to gain in importance in the coming years.
Collapse
Affiliation(s)
- Marina Creydt
- Hamburg School of Food Science - Institute of Food Chemistry, University of Hamburg, Hamburg, Germany
| | - Markus Fischer
- Hamburg School of Food Science - Institute of Food Chemistry, University of Hamburg, Hamburg, Germany
| |
Collapse
|
2
|
Wild M, Stolz F, Naumov S, Abel B. On the in situ formation of carbenes in ionic liquids. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1974589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Martin Wild
- Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Leipzig, Germany
| | - Ferdinand Stolz
- Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Leipzig, Germany
| | - Sergej Naumov
- Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Leipzig, Germany
| |
Collapse
|
3
|
Urban RD, Fischer TG, Charvat A, Wink K, Krafft B, Ohla S, Zeitler K, Abel B, Belder D. On-chip mass spectrometric analysis in non-polar solvents by liquid beam infrared matrix-assisted laser dispersion/ionization. Anal Bioanal Chem 2021; 413:1561-1570. [PMID: 33479818 PMCID: PMC7921053 DOI: 10.1007/s00216-020-03115-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/01/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022]
Abstract
By the on-chip integration of a droplet generator in front of an emitter tip, droplets of non-polar solvents are generated in a free jet of an aqueous matrix. When an IR laser irradiates this free liquid jet consisting of water as the continuous phase and the non-polar solvent as the dispersed droplet phase, the solutes in the droplets are ionized. This ionization at atmospheric pressure enables the mass spectrometric analysis of non-polar compounds with the aid of a surrounding aqueous matrix that absorbs IR light. This works both for non-polar solvents such as n-heptane and for water non-miscible solvents like chloroform. In a proof of concept study, this approach is applied to monitor a photooxidation of N-phenyl-1,2,3,4-tetrahydroisoquinoline. By using water as an infrared absorbing matrix, analytes, dissolved in non-polar solvents from reactions carried out on a microchip, can be desorbed and ionized for investigation by mass spectrometry.
Collapse
Affiliation(s)
- Raphael D Urban
- Institut für Analytische Chemie, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany
| | - Tillmann G Fischer
- Institut für Organische Chemie, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Ales Charvat
- Leibniz-Institut für Oberflächenmodifizierung e.V., Abteilung Funktionale Oberflächen, Permoserstr. 15, 04318, Leipzig, Germany
| | - Konstantin Wink
- Institut für Analytische Chemie, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany
| | - Benjamin Krafft
- Institut für Analytische Chemie, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany
| | - Stefan Ohla
- Institut für Analytische Chemie, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany
| | - Kirsten Zeitler
- Institut für Organische Chemie, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Bernd Abel
- Leibniz-Institut für Oberflächenmodifizierung e.V., Abteilung Funktionale Oberflächen, Permoserstr. 15, 04318, Leipzig, Germany
| | - Detlev Belder
- Institut für Analytische Chemie, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany.
| |
Collapse
|
4
|
Villatoro J, Zühlke M, Riebe D, Beitz T, Weber M, Löhmannsröben HG. Sub-ambient pressure IR-MALDI ion mobility spectrometer for the determination of low and high field mobilities. Anal Bioanal Chem 2020; 412:5247-5260. [PMID: 32488389 DOI: 10.1007/s00216-020-02735-0] [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: 03/10/2020] [Revised: 05/16/2020] [Accepted: 05/20/2020] [Indexed: 11/25/2022]
Abstract
A new ion mobility (IM) spectrometer, enabling mobility measurements in the pressure range between 5 and 500 mbar and in the reduced field strength range E/N of 5-90 Td, was developed and characterized. Reduced mobility (K0) values were studied under low E/N (constant value) as well as high E/N (deviation from low field K0) for a series of molecular ions in nitrogen. Infrared matrix-assisted laser desorption ionization (IR-MALDI) was used in two configurations: a source working at atmospheric pressure (AP) and, for the first time, an IR-MALDI source working with a liquid (aqueous) matrix at sub-ambient/reduced pressure (RP). The influence of RP on IR-MALDI was examined and new insights into the dispersion process were gained. This enabled the optimization of the IM spectrometer for best analytical performance. While ion desolvation is less efficient at RP, the transport of ions is more efficient, leading to intensity enhancement and an increased number of oligomer ions. When deciding between AP and RP IR-MALDI, a trade-off between intensity and resolving power has to be considered. Here, the low field mobility of peptide ions was first measured and compared with reference values from ESI-IM spectrometry (at AP) as well as collision cross sections obtained from molecular dynamics simulations. The second application was the determination of the reduced mobility of various substituted ammonium ions as a function of E/N in nitrogen. The mobility is constant up to a threshold at high E/N. Beyond this threshold, mobility increases were observed. This behavior can be explained by the loss of hydrated water molecules.
Collapse
Affiliation(s)
- José Villatoro
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany. .,Konrad-Zuse-Zentrum für Informationstechnik Berlin, Takustraße 7, 14195, Berlin-Dahlem, Germany.
| | - Martin Zühlke
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Daniel Riebe
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Toralf Beitz
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Marcus Weber
- Konrad-Zuse-Zentrum für Informationstechnik Berlin, Takustraße 7, 14195, Berlin-Dahlem, Germany
| | - Hans-Gerd Löhmannsröben
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| |
Collapse
|
5
|
Iguchi Y, Hazama H, Awazu K. Continuous flow reduced-pressure infrared laser desorption/ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1845-1850. [PMID: 28850755 DOI: 10.1002/rcm.7970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 08/04/2017] [Accepted: 08/19/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE Continuous flow ionization methods using infrared (IR) lasers have several favorable characteristics, including ionization without any additional matrices and tolerance to contaminants such as detergents and buffer salts. However, poor sensitivity due to low ion-transfer efficiency from the sample plate to the inlet capillary of the mass spectrometer under atmospheric pressure remains a serious problem. METHODS We developed a new continuous flow IR laser desorption/ionization (IR-LDI) method using a frit plate and wavelength-tunable mid-IR laser with an optical parametric oscillator. Continuous flow samples were directly injected into the ion source without any additional matrices. The ion source was covered with a decompression chamber, and could vary the pressure of the ion source from 21 to 101 kPa. RESULTS Reduction of the pressure of the IR-LDI source from 101 to 71 kPa increased the signal intensity for the [M + H]+ ion of angiotensin II by 1.8-fold. On the other hand, the ion signal intensity was reduced at pressures lower than 71 kPa. It became clear that reducing pressure was more effective when ionization occurred with lower laser pulse energy and lower ion source temperature. In addition, signal intensities for the [M + 2H]2+ and [M + 3H]3+ ions of insulin were also increased, by 1.4-fold and 1.1-fold, respectively, upon reduction of the pressure to 91 and 81 kPa. CONCLUSIONS Although many studies have described IR-LDI using a differential pumping mass spectrometer, the optimal pressure of the ion source has never been investigated. We found that a slight reduction in pressure enhances sensitivity. This knowledge may be applicable to a number of ambient ionization methods using IR lasers.
Collapse
Affiliation(s)
- Yasunari Iguchi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hisanao Hazama
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Global Center for Medical Engineering and Informatics, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
6
|
Schulze S, Pahl M, Stolz F, Appun J, Abel B, Schneider C, Belder D. Liquid Beam Desorption Mass Spectrometry for the Investigation of Continuous Flow Reactions in Microfluidic Chips. Anal Chem 2017; 89:6175-6181. [PMID: 28489359 DOI: 10.1021/acs.analchem.7b01026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, we present the combination of microfluidic chips and mass spectrometry employing laser-induced liquid beam ionization/desorption. The developed system was evaluated with respect to stable beam generation and laser parameters as well as solvent compatibility. The device was exemplarily applied to study a vinylogous Mannich reaction performed in continuous flow on chip. Fast processes can be observed with this technique which in the future could be beneficial for studying intermediates or contribute to the elucidation of reaction mechanisms.
Collapse
Affiliation(s)
- Sandra Schulze
- Institute of Analytical Chemistry, University Leipzig , Linnéstraße 3, 04103 Leipzig, Germany
| | - Maik Pahl
- Institute of Analytical Chemistry, University Leipzig , Linnéstraße 3, 04103 Leipzig, Germany
| | - Ferdinand Stolz
- Wilhelm-Ostwald-Institute of Physical and Theoretical Chemistry, University Leipzig , Linnéstraße 3, 04103 Leipzig, Germany.,Leibniz Institute of Surface Modification (IOM) , Permoserstraße 15, 04318 Leipzig, Germany
| | - Johannes Appun
- Institute of Organic Chemistry, University Leipzig , Johannisallee 29, 04103 Leipzig, Germany
| | - Bernd Abel
- Wilhelm-Ostwald-Institute of Physical and Theoretical Chemistry, University Leipzig , Linnéstraße 3, 04103 Leipzig, Germany.,Leibniz Institute of Surface Modification (IOM) , Permoserstraße 15, 04318 Leipzig, Germany
| | - Christoph Schneider
- Institute of Organic Chemistry, University Leipzig , Johannisallee 29, 04103 Leipzig, Germany
| | - Detlev Belder
- Institute of Analytical Chemistry, University Leipzig , Linnéstraße 3, 04103 Leipzig, Germany
| |
Collapse
|
7
|
Stolz F, Appun J, Naumov S, Schneider C, Abel B. A Complex Catalytic Reaction Caught in the Act: Intermediates and Products Sampling Online by Liquid μ-Beam Mass Spectrometry and Theoretical Modeling. Chempluschem 2016; 82:233-240. [PMID: 31961544 DOI: 10.1002/cplu.201600347] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/25/2016] [Indexed: 11/08/2022]
Abstract
Liquid-beam IR-laser desorption mass spectrometry has been used to monitor the reactants, intermediates, and products of a complex organic signature reaction in real time on multiple timescales directly from the liquid phase. The reaction was chosen because it has advantages in medicinal chemistry applications, and the three-component, modular construction provides a means to generate molecular diversity rapidly. Under Lewis acid catalysis, a vinylogous Mannich reaction was monitored as it generated a δ-amino-α-silyloxy-α,β-unsaturated ester, which upon hydrolysis to the corresponding α-keto ester spontaneously reacted in a [3+2] cycloannulation to the final pyrrolo[2,1-b]benzoxazole. The kinetic data were compared with predictions of quantum chemical calculations to elucidate and verify or exclude reaction pathways and mechanisms for a possible rational optimization of the reaction. The simplicity and rapid response of this approach make it a very powerful technique for online characterization of chemical reactions on timescales spanning several orders of magnitude. This enables full control over chemical reactions, thereby maximizing the product yield. This combined experimental and theoretical approach opens up a new route for the study of novel chemistry in liquid-phase reactions.
Collapse
Affiliation(s)
- Ferdinand Stolz
- Leibniz Institute of Surface Modification, Permoserstrasse 15, 04317, Leipzig, Germany
| | - Johannes Appun
- Institut für Organische Chemie, Universität Leipzig, Johannisalle 29, 04103, Leipzig, Germany
| | - Sergej Naumov
- Leibniz Institute of Surface Modification, Permoserstrasse 15, 04317, Leipzig, Germany
| | - Christoph Schneider
- Institut für Organische Chemie, Universität Leipzig, Johannisalle 29, 04103, Leipzig, Germany
| | - Bernd Abel
- Leibniz Institute of Surface Modification, Permoserstrasse 15, 04317, Leipzig, Germany.,Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, 04103, Leipzig, Germany
| |
Collapse
|
8
|
IR-MALDI ion mobility spectrometry. Anal Bioanal Chem 2016; 408:6259-68. [PMID: 27370689 DOI: 10.1007/s00216-016-9739-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/07/2016] [Accepted: 06/22/2016] [Indexed: 10/21/2022]
Abstract
The novel combination of infrared matrix-assisted laser dispersion and ionization (IR-MALDI) with ion mobility (IM) spectrometry makes it possible to investigate biomolecules in their natural environment, liquid water. As an alternative to an ESI source, the IR-MALDI source was implemented in an in-house-developed ion mobility (IM) spectrometer. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse (λ = 2.94 μm, 6 ns pulse width), which disperses the liquid as nano- and micro-droplets. The prerequisites for the application of IR-MALDI-IM spectrometry as an analytical method are narrow analyte ion signal peaks for a high spectrometer resolution. This can only be achieved by improving the desolvation of ions. One way to full desolvation is to give the cluster ions sufficient time to desolvate. Two methods for achieving this are studied: the implementation of an additional drift tube, as in ESI-IM-spectrometry, and the delayed extraction of the ions. As a result of this optimization procedure, limits of detection between 5 nM and 2.5 μM as well as linear dynamic ranges of 2-3 orders of magnitude were obtained for a number of substances. The ability of this method to analyze simple mixtures is illustrated by the separation of two different surfactant mixtures.
Collapse
|
9
|
Wiederschein F, Vöhringer-Martinez E, Beinsen A, Postberg F, Schmidt J, Srama R, Stolz F, Grubmüller H, Abel B. Charge separation and isolation in strong water droplet impacts. Phys Chem Chem Phys 2015; 17:6858-64. [PMID: 25672904 DOI: 10.1039/c4cp05618c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Charge separation in condensed matter after strong impacts is a general and intriguing phenomenon in nature, which is often identified and described but not necessarily well understood in terms of a quantitative mechanistic picture. Here we show that charge separation naturally occurs if water droplets/clusters or ice particles with embedded charge carriers, e.g., ions, encounter a high energy impact with subsequent dispersion - even if the involved kinetic energy is significantly below the molecular ionization energy. We find that for low charge carrier concentrations (c < 0.01 mol L(-1)) a simple statistical Poisson model describes the charge distribution in the resulting molecular "fragments" or aggregates. At higher concentrations Coulomb interactions between the charge carriers become relevant, which we describe by a Monte Carlo approach. Our models are compared to experimental data for strong (laser) impacts on liquid micro beams and discussed for the charge generation in cluster-impact mass spectrometry on cosmic dust detectors where particle kinetic energies are below the plasma threshold. Taken together, a simple and intuitive but quantitative microscopic model is obtained, which may contribute to the understanding of a larger range of phenomena related to charge generation and separation in nature.
Collapse
Affiliation(s)
- F Wiederschein
- MPI für biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Warschat C, Stindt A, Panne U, Riedel J. Mass Spectrometry of Levitated Droplets by Thermally Unconfined Infrared-Laser Desorption. Anal Chem 2015; 87:8323-7. [DOI: 10.1021/acs.analchem.5b01495] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carsten Warschat
- BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse
11, 12489 Berlin, Germany
| | - Arne Stindt
- BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse
11, 12489 Berlin, Germany
| | - Ulrich Panne
- BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse
11, 12489 Berlin, Germany
- Department
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse
2, 12489 Berlin, Germany
| | - Jens Riedel
- BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse
11, 12489 Berlin, Germany
| |
Collapse
|
11
|
Gladytz T, Abel B, Siefermann KR. Expansion dynamics of supercritical water probed by picosecond time-resolved photoelectron spectroscopy. Phys Chem Chem Phys 2015; 17:4926-36. [PMID: 25559696 DOI: 10.1039/c4cp05171h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vibrational excitation of liquid water with femtosecond laser pulses can create extreme states of water. Yet, the dynamics directly after initial sub-picosecond delocalization of molecular vibrations remain largely unclear. We study the ultrafast expansion dynamics of an accordingly prepared supercritical water phase with a picosecond time resolution. Our experimental setup combines vacuum-compatible liquid micro-jet technology and a table top High Harmonic light source driven by a femtosecond laser system. An ultrashort laser pulse centered at a wavelength of 2900 nm excites the OH-stretch vibration of water molecules in the liquid. The deposited energy corresponds to a supercritical phase with a temperature of about 1000 K and a pressure of more than 1 GPa. We use a time-delayed extreme ultraviolet pulse centered at 38.6 eV, and obtained via High Harmonic generation (HHG), to record valence band photoelectron spectra of the expanding water sample. The series of photoelectron spectra is analyzed with noise-corrected target transform fitting (cTTF), a specifically developed multivariate method. Together with a simple fluid dynamics simulation, the following picture emerges: when a supercritical phase of water expands into vacuum, temperature and density of the first few nanometers of the expanding phase drop below the critical values within a few picoseconds. This results in a supersaturated phase, in which condensation seeds form and grow from small clusters to large clusters on a 100 picosecond timescale.
Collapse
Affiliation(s)
- Thomas Gladytz
- Leibniz-Institute of Surface Modification (IOM), Chemistry Department, Permoserstr. 15, 04318 Leipzig, Germany.
| | | | | |
Collapse
|
12
|
Hiraguchi R, Hazama H, Masuda K, Awazu K. Atmospheric pressure laser desorption/ionization using a 6-7 µm-band mid-infrared tunable laser and liquid water matrix. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:65-70. [PMID: 25601676 DOI: 10.1002/jms.3473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 08/17/2014] [Accepted: 08/19/2014] [Indexed: 06/04/2023]
Abstract
Due to the characteristic absorption peaks in the IR region, various molecules can be used as a matrix for infrared matrix-assisted laser desorption/ionization (IR-MALDI). Especially in the 6-7 µm-band IR region, solvents used as the mobile phase for liquid chromatography have absorption peaks that correspond to their functional groups, such as O-H, C=O, and CH3. Additionally, atmospheric pressure (AP) IR-MALDI, which is applicable to liquid-state samples, is a promising technique to directly analyze untreated samples. Herein we perform AP-IR-MALDI mass spectrometry of a peptide, angiotensin II, using a mid-IR tunable laser with a tunable wavelength range of 5.50-10.00 µm and several different matrices. The wavelength dependences of the ion signal intensity of [M + H](+) of the peptide are measured using a conventional solid matrix, α-cyano-4-hydroxycinnamic acid (CHCA) and a liquid matrix composed of CHCA and 3-aminoquinoline. Other than the O-H stretching and bending vibration modes, the characteristic absorption peaks are useful for AP-IR-MALDI. Peptide ions are also observed from an aqueous solution of the peptide without an additional matrix, and the highest peak intensity of [M + H](+) is at 6.00 µm, which is somewhat shorter than the absorption peak wavelength of liquid water corresponding to the O-H bending vibration mode. Moreover, long-lasting and stable ion signals are obtained from the aqueous solution. AP-IR-MALDI using a 6-7 µm-band IR tunable laser and solvents as the matrix may provide a novel on-line interface between liquid chromatography and mass spectrometry.
Collapse
Affiliation(s)
- Ryuji Hiraguchi
- Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | | | | | | |
Collapse
|
13
|
Hiraguchi R, Hazama H, Senoo K, Yahata Y, Masuda K, Awazu K. Continuous flow atmospheric pressure laser desorption/ionization using a 6-7-µm-band mid-infrared tunable laser for biomolecular mass spectrometry. Int J Mol Sci 2014; 15:10821-34. [PMID: 24937686 PMCID: PMC4100183 DOI: 10.3390/ijms150610821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 01/29/2023] Open
Abstract
A continuous flow atmospheric pressure laser desorption/ionization technique using a porous stainless steel probe and a 6-7-µm-band mid-infrared tunable laser was developed. This ion source is capable of direct ionization from a continuous flow with a high temporal stability. The 6-7-µm wavelength region corresponds to the characteristic absorption bands of various molecular vibration modes, including O-H, C=O, CH3 and C-N bonds. Consequently, many organic compounds and solvents, including water, have characteristic absorption peaks in this region. This ion source requires no additional matrix, and utilizes water or acetonitrile as the solvent matrix at several absorption peak wavelengths (6.05 and 7.27 µm, respectively). The distribution of multiply-charged peptide ions is extremely sensitive to the temperature of the heated capillary, which is the inlet of the mass spectrometer. This ionization technique has potential for the interface of liquid chromatography/mass spectrometry (LC/MS).
Collapse
Affiliation(s)
- Ryuji Hiraguchi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Hisanao Hazama
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | | | - Yukinori Yahata
- JEOL Ltd., 1156 Nakagamicho, Akishima, Tokyo 196-0022, Japan.
| | - Katsuyoshi Masuda
- Suntory Institute for Bioorganic Research, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamotocho, Mishimagun, Osaka 618-0024, Japan.
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| |
Collapse
|
14
|
CO2 laser ionization of acoustically levitated droplets. Anal Bioanal Chem 2012; 405:7005-10. [DOI: 10.1007/s00216-012-6500-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/10/2012] [Accepted: 10/11/2012] [Indexed: 10/27/2022]
|
15
|
Sugiyama A, Nakajima A. Wavelength Dependence of IR Laser for Dual-laser Shattering of a Water Microdroplet. CHEM LETT 2012. [DOI: 10.1246/cl.2012.1481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Akinori Sugiyama
- Department of Chemistry, Faculty of Science and Technology, Keio University
| | - Atsushi Nakajima
- Department of Chemistry, Faculty of Science and Technology, Keio University
- JST-ERATO, Nakajima Designer Nanocluster Assembly Project
| |
Collapse
|
16
|
Pirkl A, Soltwisch J, Draude F, Dreisewerd K. Infrared matrix-assisted laser desorption/ionization orthogonal-time-of-flight mass spectrometry employing a cooling stage and water ice as a matrix. Anal Chem 2012; 84:5669-76. [PMID: 22670870 DOI: 10.1021/ac300840b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although water ice has been utilized in the past as a matrix for infrared matrix-assisted laser desorption/ionization mass spectrometry (IR-MALDI-MS), it has not found a wider use due to limitations in the analytical performance and technical demands on the employment of the necessary cooling stage. Here, we developed a temperature-controlled sample stage for use with an orthogonal time-of-flight mass spectrometer (MALDI-o-TOF-MS). The stage utilizes a combination of liquid nitrogen cooling and counterheating with a Peltier element. It allows adjustment of the sample temperature between ~-120 °C and room temperature. To identify optimal irradiation conditions for IR-MALDI with the water ice matrix, we first investigated the influence of excitation wavelength, varied between 2.7 and 3.1 μm, and laser fluence on the signal intensities of molecular substance P ions. These data suggest the involvement of transient melting of the ice during the laser pulse and primary energy deposition into liquid water. As a consequence, the best analytical performance is obtained at a wavelength corresponding to the absorption maximum of liquid water of about 2.94 μm. The current data significantly surpass the previously reported analytical features. The particular softness of the method is, for example, exemplified by the analysis of noncovalently bound holo-myoglobin and of ribonuclease B. This is also the first report demonstrating the analysis of an IgG monoclonal antibody (MW ~ 150 kDa) from a water ice matrix. Untypical for MALDI-MS, high charge states of multiply protonated species were moreover observed for some of the investigated peptides and even for lacto-N-fucopentaose II oligosaccharides. Using water ice as matrix is of particular interest for MALDI MS profiling and imaging applications since matrix-free spectra are produced. The MS and tandem MS analysis of metabolites directly from frozen food samples is demonstrated with the example of a strawberry fruit.
Collapse
Affiliation(s)
- Alexander Pirkl
- Institute of Medical Physics and Biophysics, University of Münster, Münster, Germany
| | | | | | | |
Collapse
|
17
|
Applications of Ionic Liquids in Electrochemical Sensors and Biosensors. INTERNATIONAL JOURNAL OF ELECTROCHEMISTRY 2012. [DOI: 10.1155/2012/165683] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Ionic liquids (ILs) are salt that exist in the liquid phase at and around 298 K and are comprised of a bulky, asymmetric organic cation and the anion usually inorganic ion but some ILs also with organic anion. ILs have attracted much attention as a replacement for traditional organic solvents as they possess many attractive properties. Among these properties, intrinsic ion conductivity, low volatility, high chemical and thermal stability, low combustibility, and wide electrochemical windows are few. Due to negligible or nonzero volatility of these solvents, they are considered “greener” for the environment as they do not evaporate like volatile organic compounds (VOCs). ILs have been widely used in electrodeposition, electrosynthesis, electrocatalysis, electrochemical capacitor, lubricants, plasticizers, solvent, lithium batteries, solvents to manufacture nanomaterials, extraction, gas absorption agents, and so forth. Besides a brief discussion of the introduction, history, and properties of ILs the major purpose of this review paper is to provide an overview on the advantages of ILs for the synthesis of conducting polymer and nanoparticle when compared to conventional media and also to focus on the electrochemical sensors and biosensors based on IL/composite modified macrodisk electrodes. Subsequently, recent developments and major strategies for enhancing sensing performance are discussed.
Collapse
|
18
|
Kohno JY, Kondow T. Trap of Biomolecular Ions in the Gas Phase Produced by IR-laser Ablation of Droplet Beam. CHEM LETT 2010. [DOI: 10.1246/cl.2010.1220] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|