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van Wasen S, You Y, Beck S, Riedel J, Volmer DA. Laser Ablation Secondary Electrospray Ionization for In Situ Mass Spectrometric Interrogation of Acoustically-Levitated Droplets. Anal Chem 2022; 94:16992-16996. [PMID: 36450044 DOI: 10.1021/acs.analchem.2c03800] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The composition of acoustically levitated droplets was probed by a novel combination of mid-IR laser evaporation and subsequent postionization via secondary electrospray ionization. The combination of microliter samples and subnanoliter sampling provided time-resolved interrogation of droplets and allowed for a kinetic investigation of the laser-induced release of the analyte, which was found to strongly depend on the analytes. The observed substance-specific delayed release of the analytes permitted baseline-separated discrimination of the analytes, ideal for the study of complex samples. The additionally applied postionization scheme was found to enable efficient detection of small volatile compounds as well as peptides. The detection of small molecules and peptides occurred under very different sampling geometries, pointing to two distinct underlying ionization mechanisms. Overall, our results suggest that the experimental setup presented in this study can serve as a widely applicable platform to study chemical reactions in acoustically levitated droplets as model reactors.
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Affiliation(s)
- Sebastian van Wasen
- Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Yi You
- Bundesanstalt für Materialforschung und -Prüfung (BAM), 12489 Berlin, Germany
| | - Sebastian Beck
- Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Jens Riedel
- Bundesanstalt für Materialforschung und -Prüfung (BAM), 12489 Berlin, Germany
| | - Dietrich A Volmer
- Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
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2
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Kafeenah H, Jen HH, Chen SH. Microdroplet mass spectrometry: Accelerating reaction and application. Electrophoresis 2021; 43:74-81. [PMID: 34591317 DOI: 10.1002/elps.202100208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/29/2021] [Accepted: 09/25/2021] [Indexed: 12/17/2022]
Abstract
Electrospray ionization (ESI) and desorption electrospray ionization (DESI) are common soft ionization method of mass spectrometry (MS). However, recent studies revealed that some chemical reactions can be induced or greatly accelerated in the sprayed microdroplets compared to the same reaction in the bulk. These open a new area in using microdroplet MS to explore new chemistry and develop new applications. This minireview will introduce microdroplet chemistries and explore various microdroplet techniques most of which are ESI- or DESI-based extensions by incorporating transfer tube, supersonic nebulizing gas, droplet fusion, spray extraction, laser irradiation, or laser ablation for online/offline MS analysis. Potential applications associated with new techniques, including real-time reaction monitoring, high-throughput reaction screening, protein identification, and protein characterization, are also described. Future outlook, such as coupling microdroplet MS with separation techniques, is proposed and discussed.
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Affiliation(s)
- Husam Kafeenah
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Hsiang Jen
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Hui Chen
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan
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3
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van Wasen S, You Y, Beck S, Riedel J, Volmer DA. Quantitative Analysis of Pharmaceutical Drugs Using a Combination of Acoustic Levitation and High Resolution Mass Spectrometry. Anal Chem 2021; 93:6019-6024. [PMID: 33835771 DOI: 10.1021/acs.analchem.1c00762] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A combination of acoustic levitation, laser vaporization, and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is presented in this study that enabled sensitive analysis of pharmaceutical drugs from an aqueous sample matrix. An unfocused pulsed infrared laser provided contactless sample desorption from the droplets trapped inside an acoustic levitator by activation of the OH stretching band of aqueous and alcoholic solvents. Subsequent atmospheric pressure chemical ionization was used between the levitated droplet and the mass spectrometer for postionization. In this setup, the unfocused laser gently desorbed the analytes by applying very mild repulsive forces. Detailed plume formation studies by temporally resolved schlieren experiments were used to characterize the liquid gas transition in this process. In addition, the role of different additives and solvent composition was examined during the ionization process. The analytical application of the technique and the proof-of-concept for quantitative analysis were demonstrated by the determination of selected pharmaceutical drugs in aqueous matrix with limits of quantification at the lower nanomolar level and a linear dynamic range of 3-4 orders of magnitude.
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Affiliation(s)
- Sebastian van Wasen
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Yi You
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Sebastian Beck
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Jens Riedel
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Dietrich A Volmer
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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4
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Wingen LM, Finlayson-Pitts BJ. Probing surfaces of atmospherically relevant organic particles by easy ambient sonic-spray ionization mass spectrometry (EASI-MS). Chem Sci 2018; 10:884-897. [PMID: 30774883 PMCID: PMC6346289 DOI: 10.1039/c8sc03851a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
EASI-MS is a promising technique for probing the chemical structures of inhomogeneous airborne organic particles.
Both ambient and laboratory-generated particles can have a surface composition different from the bulk, but there are currently few analytical techniques available to probe these differences. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) was applied to solid, laboratory-generated particles with core–shell morphologies formed from a variety of dicarboxylic acids. The soft ionization facilitated parent peak detection for the two compounds, from which the depth probed could be determined from the relative signal intensities. Two different configurations of a custom-made nebulizer are reported that yield different probe depths. In the “orthogonal mode,” with the nebulizer ∼10 centimeters away from the particle stream and at a 90° angle to the MS inlet, evaporation of the nebulizer droplets forms ions before interaction with the particles. The probe depth for orthogonal mode EASI-MS is shown to be 2–4 nm in these particle systems. In the “droplet mode”, the nebulizer and particle streams are in close proximity to each other and the MS inlet so that the particles interact with charged liquid droplets. This configuration resulted in full dissolution of the particles and gives particle composition similar to that from collection on filters and extraction of the particles (bulk). These studies establish that EASI-MS is a promising technique for probing the chemical structures of inhomogeneous airborne organic particles.
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Affiliation(s)
- L M Wingen
- Department of Chemistry , University of California Irvine , Irvine , CA 92697-2025 , USA . ; Tel: +1-949-824-7670
| | - B J Finlayson-Pitts
- Department of Chemistry , University of California Irvine , Irvine , CA 92697-2025 , USA . ; Tel: +1-949-824-7670
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5
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Thomas DA, Wang L, Goh B, Kim ES, Beauchamp JL. Mass Spectrometric Sampling of a Liquid Surface by Nanoliter Droplet Generation from Bursting Bubbles and Focused Acoustic Pulses: Application to Studies of Interfacial Chemistry. Anal Chem 2015; 87:3336-44. [DOI: 10.1021/ac504494t] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Daniel A. Thomas
- Arthur
Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Lingtao Wang
- Department
of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, California 90089, United States
| | - Byoungsook Goh
- Arthur
Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Eun Sok Kim
- Department
of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, California 90089, United States
| | - J. L. Beauchamp
- Arthur
Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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Barry JA, Robichaud G, Bokhart MT, Thompson C, Sykes C, Kashuba AD, Muddiman DC. Mapping antiretroviral drugs in tissue by IR-MALDESI MSI coupled to the Q Exactive and comparison with LC-MS/MS SRM assay. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:2038-47. [PMID: 24744212 PMCID: PMC4201889 DOI: 10.1007/s13361-014-0884-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/05/2014] [Accepted: 03/08/2014] [Indexed: 05/09/2023]
Abstract
This work describes the coupling of the IR-MALDESI imaging source with the Q Exactive mass spectrometer. IR-MALDESI MSI was used to elucidate the spatial distribution of several HIV drugs in cervical tissues that had been incubated in either a low or high concentration. Serial sections of those analyzed by IR-MALDESI MSI were homogenized and analyzed by LC-MS/MS to quantify the amount of each drug present in the tissue. By comparing the two techniques, an agreement between the average intensities from the imaging experiment and the absolute quantities for each drug was observed. This correlation between these two techniques serves as a prerequisite to quantitative IR-MALDESI MSI. In addition, a targeted MS(2) imaging experiment was also conducted to demonstrate the capabilities of the Q Exactive and to highlight the added selectivity that can be obtained with SRM or MRM imaging experiments.
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Affiliation(s)
- Jeremy A. Barry
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Guillaume Robichaud
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Mark T. Bokhart
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Corbin Thompson
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - Craig Sykes
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - Angela D.M. Kashuba
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - David C. Muddiman
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
- Author for Correspondence: David C. Muddiman, Ph.D., W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, Phone: 919-513-0084, Fax: 919-513-7993,
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7
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Robichaud G, Barry JA, Muddiman DC. IR-MALDESI mass spectrometry imaging of biological tissue sections using ice as a matrix. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:319-28. [PMID: 24385399 PMCID: PMC3950934 DOI: 10.1007/s13361-013-0787-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 11/14/2013] [Accepted: 11/16/2013] [Indexed: 05/04/2023]
Abstract
Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging of biological tissue sections using a layer of deposited ice as an energy-absorbing matrix was investigated. Dynamics of plume ablation were first explored using a nanosecond exposure shadowgraphy system designed to simultaneously collect pictures of the plume with a camera and collect the Fourier transform ion cyclotron resonance FT-ICR mass spectrum corresponding to that same ablation event. Ablation of fresh tissue analyzed with and without using ice as a matrix were compared using this technique. Effect of spot-to-spot distance, number of laser shots per pixel, and tissue condition (matrix) on ion abundance were also investigated for 50 μm-thick tissue sections. Finally, the statistical method called design of experiments was used to compare source parameters and determine the optimal conditions for IR-MALDESI of tissue sections using deposited ice as a matrix. With a better understanding of the fundamentals of ablation dynamics and a systematic approach to explore the experimental space, it was possible to improve ion abundance by nearly one order of magnitude.
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Affiliation(s)
| | | | - David C. Muddiman
- Author for Correspondence. David C. Muddiman, Ph.D., W.M. Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, Phone: 919-513-0084,
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8
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Flanigan P, Levis R. Ambient femtosecond laser vaporization and nanosecond laser desorption electrospray ionization mass spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2014; 7:229-256. [PMID: 25014343 DOI: 10.1146/annurev-anchem-071213-020343] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Recent investigations of ambient laser-based transfer of molecules into the gas phase for subsequent mass spectral analysis have undergone a renaissance resulting from the separation of vaporization and ionization events. Here, we seek to provide a snapshot of recent femtosecond (fs) duration laser vaporization and nanosecond (ns) duration laser desorption electrospray ionization mass spectrometry experiments. The former employs pulse durations of <100 fs to enable matrix-free laser vaporization with little or no fragmentation. When coupled to electrospray ionization, femtosecond laser vaporization provides a universal, rapid mass spectral analysis method requiring no sample workup. Remarkably, laser pulses with intensities exceeding 10(13) W cm(-2) desorb intact macromolecules, such as proteins, and even preserve the condensed phase of folded or unfolded protein structures according to the mass spectral charge state distribution, as demonstrated for cytochrome c and lysozyme. Because of the ability to vaporize and ionize multiple components from complex mixtures for subsequent analysis, near perfect classification of explosive formulations, plant tissue phenotypes, and even the identity of the manufacturer of smokeless powders can be determined by multivariate statistics. We also review the more mature field of nanosecond laser desorption for ambient mass spectrometry, covering the wide range of systems analyzed, the need for resonant absorption, and the spatial imaging of complex systems like tissue samples.
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Affiliation(s)
- Paul Flanigan
- Center for Advanced Photonics Research, Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122; ,
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9
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Laskin J, Laskin A, Nizkorodov SA. New mass spectrometry techniques for studying physical chemistry of atmospheric heterogeneous processes. INT REV PHYS CHEM 2013. [DOI: 10.1080/0144235x.2012.752904] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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10
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Badu-Tawiah AK, Eberlin LS, Ouyang Z, Cooks RG. Chemical aspects of the extractive methods of ambient ionization mass spectrometry. Annu Rev Phys Chem 2013; 64:481-505. [PMID: 23331308 DOI: 10.1146/annurev-physchem-040412-110026] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ambient ionization techniques allow complex chemical samples to be analyzed in their native state with minimal sample preparation. This brings the obvious advantages of simplicity, speed, and versatility to mass spectrometry: Desorption electrospray ionization (DESI), for example, is used in chemical imaging for tumor margin diagnosis. This review on the extractive methods of ambient ionization focuses on chemical aspects, mechanistic considerations, and the accelerated chemical reactions occurring in charged liquid droplets generated in the spray process. DESI uses high-velocity solvent droplets to extract analytes from surfaces. Nano-DESI employs liquid microjunctions for analyte dissolution, whereas paper-spray ionization uses DC potentials applied to wet porous material such as paper or biological tissue to field emit charged analyte-containing solvent droplets. These methods also operate in a reactive mode in which added reagents allow derivatization during ionization. The accelerated reaction rates seen in charged microdroplets are useful in small-scale rapid chemical synthesis.
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11
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Monge ME, Harris GA, Dwivedi P, Fernández FM. Mass Spectrometry: Recent Advances in Direct Open Air Surface Sampling/Ionization. Chem Rev 2013; 113:2269-308. [DOI: 10.1021/cr300309q] [Citation(s) in RCA: 404] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- María Eugenia Monge
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Glenn A. Harris
- Department
of Biochemistry and
the Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Prabha Dwivedi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Facundo M. Fernández
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
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12
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Robichaud G, Barry JA, Garrard KP, Muddiman DC. Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) imaging source coupled to a FT-ICR mass spectrometer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013. [PMID: 23208743 PMCID: PMC3689149 DOI: 10.1007/s13361-012-0505-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mass spectrometry imaging (MSI) allows for the direct monitoring of the abundance and spatial distribution of chemical compounds over the surface of a tissue sample. This technology has opened the field of mass spectrometry to numerous innovative applications over the past 15 years. First used with SIMS and MALDI MS that operate under vacuum, interest has grown for mass spectrometry ionization sources that allow for effective imaging but where the analysis can be performed at ambient pressure with minimal or no sample preparation. We introduce here a versatile source for MALDESI imaging analysis coupled to a hybrid LTQ-FT-ICR mass spectrometer. The imaging source offers single shot or multi-shot capability per pixel with full control over the laser repetition rate and mass spectrometer scanning cycle. Scanning rates can be as fast as 1 pixel/second and a spatial resolution of 45 μm was achieved with oversampling. Design and integration of a versatile IR-MALDESI imaging source offering multi-shot capability with a commercial FT-ICR mass spectrometer.
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Affiliation(s)
- Guillaume Robichaud
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Jeremy A. Barry
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Kenneth P. Garrard
- Precision Engineering Center, North Carolina State University, Campus Box 7918, Raleigh, North Carolina 27695
| | - David C. Muddiman
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
- Author for Correspondence: David C. Muddiman, Ph.D., W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, Phone: 919-513-0084, Fax: 919-513-7993,
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13
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Badu-Tawiah AK, Campbell DI, Cooks RG. Accelerated C-N bond formation in dropcast thin films on ambient surfaces. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1461-8. [PMID: 22825741 DOI: 10.1007/s13361-012-0394-y] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 05/08/2023]
Abstract
The aza-Michael addition and the Mannich condensation occur in thin films deposited on ambient surfaces. The reagents for both C-N bond formation reactions were transferred onto the surface by drop-casting using a micropipette. The surface reactions were found to be much more efficient than the corresponding bulk solution-phase reactions performed on the same scale in the same acetonitrile solvent. The increase in rate of product formation in the thin film is attributed to solvent evaporation in the open air which results in reagent concentration and produces rate acceleration similar to that seen in evaporating droplets in desorption electrospray ionization. This thin film procedure has potential for the rapid synthesis of reaction products on a small scale, as well as allowing rapid derivatization of analytes to produce forms that are easily ionized by electrospray ionization. Analysis of the derivatized sample directly from the reaction surface through the use of desorption electrospray ionization is also demonstrated.
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14
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Badu-Tawiah AK, Campbell DI, Cooks RG. Reactions of microsolvated organic compounds at ambient surfaces: droplet velocity, charge state, and solvent effects. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1077-84. [PMID: 22427191 DOI: 10.1007/s13361-012-0365-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/17/2012] [Accepted: 02/17/2012] [Indexed: 05/25/2023]
Abstract
The exposure of charged microdroplets containing organic ions to solid-phase reagents at ambient surfaces results in heterogeneous ion/surface reactions. The electrosprayed droplets were driven pneumatically in ambient air and then electrically directed onto a surface coated with reagent. Using this reactive soft landing approach, acid-catalyzed Girard condensation was achieved at an ambient surface by directing droplets containing Girard T ions onto a dry keto-steroid. The charged droplet/surface reaction was much more efficient than the corresponding bulk solution-phase reaction performed on the same scale. The increase in product yield is ascribed to solvent evaporation, which causes moderate pH values in the starting droplet to reach extreme values and increases reagent concentrations. Comparisons are made with an experiment in which the droplets were pneumatically accelerated onto the ambient surface (reactive desorption electrospray ionization, DESI). The same reaction products were observed but differences in spatial distribution were seen associated with the "splash" of the high velocity DESI droplets. In a third type of experiment, the reactions of charged droplets with vapor phase reagents were examined by allowing electrosprayed droplets containing a reagent to intercept the headspace vapor of an analyte. Deposition onto a collector surface and mass analysis showed that samples in the vapor phase were captured by the electrospray droplets, and that instantaneous derivatization of the captured sample is possible in the open air. The systems examined under this condition included the derivatization of cortisone vapor with Girard T and that of 4-phenylpyridine N-oxide and 2-phenylacetophenone vapors with ethanolamine.
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15
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Barry JA, Muddiman DC. Global optimization of the infrared matrix-assisted laser desorption electrospray ionization (IR MALDESI) source for mass spectrometry using statistical design of experiments. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:3527-36. [PMID: 22095501 PMCID: PMC3781580 DOI: 10.1002/rcm.5262] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Design of experiments (DOE) is a systematic and cost-effective approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response can be measured in few experiments. Herein, we describe the use of statistical DOE to improve a few of the analytical figures of merit of the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for mass spectrometry. In a typical experiment, bovine cytochrome c was ionized via electrospray, and equine cytochrome c was desorbed and ionized by IR-MALDESI such that the ratio of equine:bovine was used as a measure of the ionization efficiency of IR-MALDESI. This response was used to rank the importance of seven source parameters including flow rate, laser fluence, laser repetition rate, ESI emitter to mass spectrometer inlet distance, sample stage height, sample plate voltage, and the sample to mass spectrometer inlet distance. A screening fractional factorial DOE was conducted to designate which of the seven parameters induced the greatest amount of change in the response. These important parameters (flow rate, stage height, sample to mass spectrometer inlet distance, and laser fluence) were then studied at higher resolution using a full factorial DOE to obtain the globally optimized combination of parameter settings. The optimum combination of settings was then compared with our previously determined settings to quantify the degree of improvement in detection limit. The limit of detection for the optimized conditions was approximately 10 attomoles compared with 100 femtomoles for the previous settings, which corresponds to a four orders of magnitude improvement in the detection limit of equine cytochrome c.
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Affiliation(s)
- Jeremy A Barry
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
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16
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Leiterer J, Panne U, Thünemann AF, Weidner SM. Container-less polymerization in acoustically levitated droplets: an analytical study by GPC and MALDI-TOF mass spectrometry. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2011; 3:70-73. [PMID: 32938112 DOI: 10.1039/c0ay00390e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Molecular masses and end groups of polystyrene (PS) formed in a novel container-less polymerization strategy, based on levitated droplets in an acoustic trap, were determined by Gel Permeation Chromatography (GPC) and Matrix-assisted Laser Desorption/Ionization Time of Flight Mass spectrometry (MALDI-TOF MS).
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Affiliation(s)
- Jork Leiterer
- BAM Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489, Berlin, Germany.
| | - Ulrich Panne
- BAM Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489, Berlin, Germany.
- Humboldt-Universitaet zu Berlin, Department of Chemistry, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Andreas F Thünemann
- BAM Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489, Berlin, Germany.
| | - Steffen M Weidner
- BAM Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489, Berlin, Germany.
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17
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Towers MW, Mckendrick JE, Cramer R. Introduction of 4-Chloro-α-cyanocinnamic Acid Liquid Matrices for High Sensitivity UV-MALDI MS. J Proteome Res 2010; 9:1931-40. [DOI: 10.1021/pr901089j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Mark W. Towers
- Department of Chemistry and The BioCentre, University of Reading, Reading, United Kingdom
| | - John E. Mckendrick
- Department of Chemistry and The BioCentre, University of Reading, Reading, United Kingdom
| | - Rainer Cramer
- Department of Chemistry and The BioCentre, University of Reading, Reading, United Kingdom
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