1
|
Díaz-Sánchez LM, Blanco-Tirado C, Combariza MY. Electron-transfer MALDI MS methodology for microalgae/phytoplankton pigments analysis. MethodsX 2023; 10:102140. [PMID: 37007620 PMCID: PMC10050785 DOI: 10.1016/j.mex.2023.102140] [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: 12/24/2022] [Accepted: 03/15/2023] [Indexed: 04/04/2023] Open
Abstract
The method describes pigment analysis from microalgae/phytoplankton extracts using electron-transfer Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (ET MALDI MS). Current microalgae/phytoplankton pigment analysis requires resource- and time-intensive chromatographic methods due to the broad polarity range of the target analytes. On the other hand, traditional MALDI MS chlorophyll analysis, using proton-transfer matrices such as 2,5-dihydroxybenzoic acid (DHB) or α-cyano-4-hydroxycinnamic acid (CHCA), results in central metal loss and phytol-ester cleavage. ET MALDI MS is an alternative for the rapid screening and detection of pigments in microalgae extracts.•MALDI matrices with ionization energies above 8.0 eV guarantee electron-transfer processes from photosynthetic and photoprotective pigments whose ionization energies lay below 7.5 eV.•ET MALDI MS pigment analysis agrees with data gathered from conventional chromatographic techniques (HPLC) and optical microscopy for pigment extracts from C. vulgaris cultures and freshwater phytoplankton samples.•The ET MALDI MS method allows fast and reliable detection of pigments in microalgae cultures and freshwater phytoplankton samples.
Collapse
|
2
|
Lin HY, Dyakov YA, Lee YT, Ni CK. Temperature Dependence of Desorbed Ions and Neutrals and Ionization Mechanism of Matrix-Assisted Laser Desorption/Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:95-105. [PMID: 32239933 DOI: 10.1021/jasms.0c00101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two separate temperature-dependent experiments were performed to investigate the ionization mechanism of ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI) of matrix 2,5-dihydroxybenzoic acid (2,5-DHB). First, the angular resolved intensity and velocity distributions of neutrals desorbed from the 2,5-DHB solid sample through UV laser (355 nm) pulse irradiation were measured using a rotating quadrupole mass spectrometer. Second, the desorbed neutrals, at an angle normal to the surface, and the desorbed ions were simultaneously detected for each laser shot using the quadrupole mass spectrometer and a time-of-flight mass spectrometer, respectively. Both experiments were conducted at two initial temperatures: 100 and 300 K. The measurements from these two experiments were used to calculate the initial temperature dependence of the ion-to-neutral ratio. The results closely agreed with the predictions of the temperature-dependent ion-to-neutral ratio using the thermal model, indicating that thermally induced proton transfer is the dominant reaction that generates initial ions of 2,5-DHB in UV-MALDI.
Collapse
Affiliation(s)
- Hou-Yu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yuri A Dyakov
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Yuan Tseh Lee
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| |
Collapse
|
3
|
Yoo HJ, Kim DH, Shin D, Oh Y, Lee S, Lee JY, Choi YJ, Lee SH, Lee KS, Kim Y, Cho K. Recent developments in pre-treatment and analytical techniques for synthetic polymers by MALDI-TOF mass spectrometry. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:5767-5800. [PMID: 33241791 DOI: 10.1039/d0ay01729a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A great deal of effort has been expended to develop accurate means of determining the properties of synthetic polymers using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS). Many studies have focused on the importance of sample pre-treatment to obtain accurate analysis results. This review discusses the history of synthetic polymer characterization and highlights several applications of MALDI-TOF MS that recognize the importance of pre-treatment technologies. The subject area is of significance in the field of analytical chemistry, especially for users of the MALDI technique. Since the 2000s, many such technologies have been developed that feature improved methods and conditions, including solvent-free systems. In addition, the recent diversification of matrix types and the development of carbon-based matrix materials are described herein together with the current status and future directions of MALDI-TOF MS hardware and software development. We provide a summary of processes used for obtaining the best analytical results with synthetic polymeric materials using MALDI-TOF MS.
Collapse
Affiliation(s)
- Hee-Jin Yoo
- Center for Research Equipment, Korea Basic Science Institute, 162, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do 28119, Korea.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Lin HY, Song BF, Ni CK. Fluorescence quantum yields of matrices used in ultraviolet matrix-assisted laser desorption/ionization. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8846. [PMID: 32469439 DOI: 10.1002/rcm.8846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/27/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE Ultraviolet matrix-assisted laser desorption/ionization (MALDI) is among the most popular soft ionization methods in mass spectrometry. Several theoretical models have been proposed to explain the primary ion generation in MALDI. These models require knowledge of various matrix molecular parameters for simulation. One such parameter is the fluorescence quantum yield. However, the fluorescence quantum yield reported in previous studies remains controversial. METHODS In this study, we used a commercial and a homemade integrating sphere to measure the absorption and fluorescence quantum yields of several commonly used matrices, including 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid (2,4-DHB), 2,5-dihydroxybenzoic acid (2,5-DHB), 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, α-cyano-4-hydroxycinnamic acid, 2,4,6-trihydroxyacetophenone, and ferulic acid. RESULTS The fluorescence quantum yields of these matrices were determined to be low (<0.08) at low laser fluences and decreased as the laser fluence increased. The fluorescence quantum yields at the typical laser fluence for MALDI are below 0.04 (2,4-DHB and 2,5-DHB) and 0.01 (the other matrices). Shot-to-shot fluctuations of fluorescence intensity and absorption are not directly related to the fluctuation of ions. Possible mechanisms for the decrease in the fluorescence quantum yield as the laser fluence increased were discussed. CONCLUSIONS The fluorescence quantum yields of these commonly used matrices are much lower than those reported in previous studies. Although fluorescence quantum yield is an important parameter and it is crucial to obtain an accurate value for theoretical models in simulations, the use of fluorescence quantum yield alone is not a sufficient parameter to justify these models.
Collapse
Affiliation(s)
- Hou-Yu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Botao Farren Song
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan
| |
Collapse
|
5
|
Cazier H, Malgorn C, Fresneau N, Georgin D, Sallustrau A, Chollet C, Tabet JC, Campidelli S, Pinault M, Mayne M, Taran F, Dive V, Junot C, Fenaille F, Colsch B. Development of a Mass Spectrometry Imaging Method for Detecting and Mapping Graphene Oxide Nanoparticles in Rodent Tissues. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1025-1036. [PMID: 32223237 DOI: 10.1021/jasms.9b00070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Graphene-based nanoparticles are continuously being developed for biomedical applications, and their use raises concerns about their environmental and biological impact. In the literature, some imaging techniques based on fluorescence and radioimaging have been used to explore their fate in vivo. Here, we report on the use of label-free mass spectrometry and mass spectrometry imaging (MSI) for graphene oxide (GO) and reduced graphene oxide (rGO) analyses in rodent tissues. Thereby, we extend previous work by focusing on practical questions to obtain reliable and meaningful images. Specific radical anionic carbon clusters ranging from C2-• to C9-• were observed for both GO and rGO species, with a base peak at m/z 72 under negative laser desorption ionization mass spectrometry (LDI-MS) conditions. Extension to an LDI-MSI method was then performed, thus enabling the efficient detection of GO nanoparticles in lung tissue sections of previously exposed mice. The possibility of quantifying those nanoparticles on tissue sections has also been investigated. Two different ways of building calibration curves (i.e., GO suspensions spotted on tissue sections, or added to lung tissue homogenates) were evaluated and returned similar results, with linear dynamic concentration ranges over at least 2 orders of magnitude. Moreover, intra- and inter-day precision studies have been assessed, with relative standard deviation below 25% for each concentration point of a calibration curve. In conclusion, our study confirms that LDI-MSI is a relevant approach for biodistribution studies of carbon-based nanoparticles, as quantification can be achieved, provided that nanoparticle suspension and manufacturing are carefully controlled.
Collapse
Affiliation(s)
- Hélène Cazier
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Carole Malgorn
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Nathalie Fresneau
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Dominique Georgin
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Antoine Sallustrau
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Céline Chollet
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Jean-Claude Tabet
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | | | - Mathieu Pinault
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Martine Mayne
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Frédéric Taran
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Vincent Dive
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Christophe Junot
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - François Fenaille
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| | - Benoit Colsch
- INRAE, Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay, CEA, 91191 Gif-sur-Yvette, France
| |
Collapse
|
6
|
Li N, Wang P, Liu X, Han C, Ren W, Li T, Li X, Tao F, Zhao Z. Developing IR-780 as a Novel Matrix for Enhanced MALDI MS Imaging of Endogenous High-Molecular-Weight Lipids in Brain Tissues. Anal Chem 2019; 91:15873-15882. [DOI: 10.1021/acs.analchem.9b04315] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Na Li
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Wang
- College of Biochemistry Engineering, Beijing Union University, Beijing 100023, China
| | - Xiaolong Liu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Han
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Ren
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tuo Li
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Li
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengyun Tao
- College of Biochemistry Engineering, Beijing Union University, Beijing 100023, China
| | - Zhenwen Zhao
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing Mass Spectrum Center, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Graduate School, University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
7
|
Nanoparticle-based surface assisted laser desorption ionization mass spectrometry: a review. Mikrochim Acta 2019; 186:682. [DOI: 10.1007/s00604-019-3770-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 08/16/2019] [Indexed: 12/28/2022]
|
8
|
Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014. MASS SPECTROMETRY REVIEWS 2018; 37:353-491. [PMID: 29687922 DOI: 10.1002/mas.21530] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/29/2016] [Indexed: 06/08/2023]
Abstract
This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.
Collapse
Affiliation(s)
- David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, United Kingdom
| |
Collapse
|
9
|
Abdelhamid HN. Ionic Liquid-Assisted Laser Desorption/Ionization-Mass Spectrometry: Matrices, Microextraction, and Separation. Methods Protoc 2018; 1:E23. [PMID: 31164566 PMCID: PMC6526421 DOI: 10.3390/mps1020023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022] Open
Abstract
Ionic liquids (ILs) have advanced a variety of applications, including matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). ILs can be used as matrices and solvents for analyte extraction and separation prior to analysis using laser desorption/ionization-mass spectrometry (LDI-MS). Most ILs show high stability with negligible sublimation under vacuum, provide high ionization efficiency, can be used for qualitative and quantitative analyses with and without internal standards, show high reproducibility, form homogenous spots during sampling, and offer high solvation efficiency for a wide range of analytes. Ionic liquids can be used as solvents and pseudo-stationary phases for extraction and separation of a wide range of analytes, including proteins, peptides, lipids, carbohydrates, pathogenic bacteria, and small molecules. This review article summarizes the recent advances of ILs applications using MALDI-MS. The applications of ILs as matrices, solvents, and pseudo-stationary phases, are also reviewed.
Collapse
|
10
|
Castellanos-García LJ, Agudelo BC, Rosales HF, Cely M, Ochoa-Puentes C, Blanco-Tirado C, Sierra CA, Combariza MY. Oligo p-Phenylenevinylene Derivatives as Electron Transfer Matrices for UV-MALDI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2548-2560. [PMID: 28879637 DOI: 10.1007/s13361-017-1783-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 08/10/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
Phenylenevinylene oligomers (PVs) have outstanding photophysical characteristics for applications in the growing field of organic electronics. Yet, PVs are also versatile molecules, the optical and physicochemical properties of which can be tuned by manipulation of their structure. We report the synthesis, photophysical, and MS characterization of eight PV derivatives with potential value as electron transfer (ET) matrices for UV-MALDI. UV-vis analysis show the presence of strong characteristic absorption bands in the UV region and molar absorptivities at 355 nm similar or higher than those of traditional proton (CHCA) and ET (DCTB) MALDI matrices. Most of the PVs exhibit non-radiative quantum yields (φ) above 0.5, indicating favorable thermal decay. Ionization potential values (IP) for PVs, calculated by the Electron Propagator Theory (EPT), range from 6.88 to 7.96 eV, making these oligomers good candidates as matrices for ET ionization. LDI analysis of PVs shows only the presence of radical cations (M+.) in positive ion mode and absence of clusters, adducts, or protonated species; in addition, M+. threshold energies for PVs are lower than for DCTB. We also tested the performance of four selected PVs as ET MALDI matrices for analytes ranging from porphyrins and phthalocyanines to polyaromatic compounds. Two of the four PVs show S/N enhancement of 1961% to 304% in comparison to LDI, and laser energy thresholds from 0.17 μJ to 0.47 μJ compared to 0.58 μJ for DCTB. The use of PV matrices also results in lower LODs (low fmol range) whereas LDI LODs range from pmol to nmol. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
| | | | - Hernando F Rosales
- Escuela de Química, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Melissa Cely
- Departamento de Química, Universidad Nacional de Colombia, Bogotá, Colombia
| | | | - Cristian Blanco-Tirado
- Escuela de Química, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Cesar A Sierra
- Departamento de Química, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Marianny Y Combariza
- Escuela de Química, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia.
| |
Collapse
|
11
|
Liang SP, Lu IC, Tsai ST, Chen JL, Lee YT, Ni CK. Laser Pulse Width Dependence and Ionization Mechanism of Matrix-Assisted Laser Desorption/Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2235-2245. [PMID: 28707193 DOI: 10.1007/s13361-017-1734-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/24/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
Ultraviolet laser pulses at 355 nm with variable pulse widths in the region from 170 ps to 1.5 ns were used to investigate the ionization mechanism of matrix-assisted laser desorption/ionization (MALDI) for matrices 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and sinapinic acid (SA). The mass spectra of desorbed ions and the intensity and velocity distribution of desorbed neutrals were measured simultaneously for each laser shot. These quantities were found to be independent of the laser pulse width. A comparison of the experimental measurements and numerical simulations according to the multiphoton ionization, coupled photophysical and chemical dynamics (CPCD), and thermally induced proton transfer models showed that the predictions of thermally induced proton transfer model were in agreement with the experimental data, but those of the multiphoton ionization model were not. Moreover, the predictions of the CPCD model based on singlet-singlet energy pooling were inconsistent with the experimental data of CHCA and SA, but were consistent with the experimental data of DHB only when some parameters used in the model were adjusted to extreme values. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Sheng-Ping Liang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - I-Chung Lu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - Shang-Ting Tsai
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Jien-Lian Chen
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Yuan Tseh Lee
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan.
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan.
| |
Collapse
|
12
|
Lai YH, Wang YS. Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry: Mechanistic Studies and Methods for Improving the Structural Identification of Carbohydrates. Mass Spectrom (Tokyo) 2017; 6:S0072. [PMID: 28959517 PMCID: PMC5610957 DOI: 10.5702/massspectrometry.s0072] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 12/21/2022] Open
Abstract
Although matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is one of the most widely used soft ionization methods for biomolecules, the lack of detailed understanding of ionization mechanisms restricts its application in the analysis of carbohydrates. Structural identification of carbohydrates achieved by MALDI mass spectrometry helps us to gain insights into biological functions and pathogenesis of disease. In this review, we highlight mechanistic details of MALDI, including both ionization and desorption. Strategies to improve the ion yield of carbohydrates are also reviewed. Furthermore, commonly used fragmentation methods to identify the structure are discussed.
Collapse
|
13
|
Mirabelli MF, Zenobi R. Observing Proton Transfer Reactions Inside the MALDI Plume: Experimental and Theoretical Insight into MALDI Gas-Phase Reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1676-1686. [PMID: 28451953 DOI: 10.1007/s13361-017-1677-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/24/2017] [Accepted: 03/25/2017] [Indexed: 06/07/2023]
Abstract
We evaluated the contribution of gas-phase in-plume proton transfer reactions to the formation of protonated and deprotonated molecules in the MALDI process. A split sample holder was used to separately deposit two different samples, which avoids any mixing during sample preparation. The two samples were brought very close to each other and desorbed/ionized by the same laser pulse. By using a combination of deuterated and non-deuterated matrices, it was possible to observe exclusively in-plume proton transfer processes. The hydrogen/deuterium exchange (HDX) kinetics were evaluated by varying the delayed extraction (DE) time, allowing the desorbed ions and neutrals to interact inside the plume for a variable period of time before being extracted and detected. Quantum mechanical calculations showed that the HDX energy barriers are relatively low for such reactions, corroborating the importance of gas-phase proton transfer in the MALDI plume. The experimental results, supported by theoretical simulations, confirm that the plume is a very reactive environment, where HDX reactions could be observed from 0 ns up to 400 ns after the laser pulse. These results could be used to evaluate the relevance of previously proposed (and partially conflicting) ionization models for MALDI. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Mario F Mirabelli
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093, Zurich, Switzerland
| | - Renato Zenobi
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093, Zurich, Switzerland.
| |
Collapse
|
14
|
Niehaus M, Schnapp A, Koch A, Soltwisch J, Dreisewerd K. New Insights into the Wavelength Dependence of MALDI Mass Spectrometry. Anal Chem 2017. [PMID: 28636332 DOI: 10.1021/acs.analchem.7b01744] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The interplay between the wavelength of the laser and the absorption profile of the matrix constitutes a crucial factor in matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). Numerous studies have shown that typically best analytical results are obtained if the laser wavelength matches the UV absorption band of the matrix in the solid state well. However, many powerful matrices exhibit peak absorptions which differ notably from the standard MALDI laser wavelengths of 337, 349, and 355 nm, respectively. Here we used two wavelength-tunable lasers to investigate the MALDI wavelength dependence with a selected set of such matrices. We studied 3-hydroxypicolinic acid (3-HPA), 2,4,6-trihydroxyacetophenon (THAP), dithranol (1,8-dihydroxy-10H-anthracen-9-on), 2-(4'-hydroxybenzeneazo)benzoic acid (HABA), and 6-aza-2-thiothymine (ATT). For analyte systems we investigated DNA oligomers (3-HPA), phospholipids (dithranol, THAP, HABA), and non-covalent peptide-peptide and protein-peptide complexes (ATT). We recorded analyte ion and total ion counts as a function of wavelength and laser fluence between 213 and 600 nm. Although the so-generated comprehensive heat maps generally corroborated the previously made findings, several fine features became notable. For example, despite a still high optical absorption exhibited by some of the matrices in the visible wavelength range, ion yields generally dropped strongly, indicating a change in ionization mechanism. Moreover, the non-covalent complexes were optimally detected at wavelengths corresponding to a relatively low optical absorptivity of the ATT matrix, presumably because of ejection of a particular cold MALDI plume. Our comprehensive data shed useful light into the MALDI mechanisms and could assist in further methodological advancement of the technique.
Collapse
Affiliation(s)
- Marcel Niehaus
- Institute for Hygiene, Biomedical Mass Spectrometry, University of Münster , D-48149 Münster, Germany
| | - Andreas Schnapp
- Institute for Hygiene, Biomedical Mass Spectrometry, University of Münster , D-48149 Münster, Germany
| | - Annika Koch
- Institute for Hygiene, Biomedical Mass Spectrometry, University of Münster , D-48149 Münster, Germany
| | - Jens Soltwisch
- Institute for Hygiene, Biomedical Mass Spectrometry, University of Münster , D-48149 Münster, Germany.,Interdisciplinary Center for Clinical Research (IZKF), University of Münster , D-48149 Münster, Germany
| | - Klaus Dreisewerd
- Institute for Hygiene, Biomedical Mass Spectrometry, University of Münster , D-48149 Münster, Germany.,Interdisciplinary Center for Clinical Research (IZKF), University of Münster , D-48149 Münster, Germany
| |
Collapse
|
15
|
Organic matrices, ionic liquids, and organic matrices@nanoparticles assisted laser desorption/ionization mass spectrometry. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.01.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
16
|
Bashir S, Liu JL, Derrick PJ. Effect of Structured Surfaces on MALDI Analyte Peak Intensities. Aust J Chem 2017. [DOI: 10.1071/ch17456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A surface modification method is presented: a sodium chloride crystal, a transparent wide bandgap insulator, was deposited onto a stainless steel surface. The surface was subjected to various stimuli to induce surface defects either on the steel surface or salt crystal and the ion yield of substance P, a model peptide, was investigated as a function of stimuli. The interaction of the laser at potential defect sites resulted in an increase in the ion yield of substance P (3–17 fold increase relative to no stimuli).
Collapse
|
17
|
Structure-performance relationships of phenyl cinnamic acid derivatives as MALDI-MS matrices for sulfatide detection. Anal Bioanal Chem 2016; 409:1569-1580. [PMID: 27909779 DOI: 10.1007/s00216-016-0096-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/28/2016] [Accepted: 11/11/2016] [Indexed: 10/20/2022]
Abstract
A key aspect for the further development of matrix-assisted laser desorption ionization (MALDI)-mass spectrometry (MS) is a better understanding of the working principles of MALDI matrices. To address this issue, a chemical compound library of 59 structurally related cinnamic acid derivatives was synthesized. Potential MALDI matrices were evaluated with sulfatides, a class of anionic lipids which are abundant in complex brain lipid mixtures. For each matrix relative mean S/N ratios of sulfatides were determined against 9-aminoacridine as a reference matrix using negative ion mass spectrometry with 355 and 337 nm laser systems. The comparison of matrix features with their corresponding relative mean S/N ratios for sulfatide detection identified correlations between matrix substitution patterns, their chemical functionality, and their MALDI-MS performance. Crystal structures of six selected matrices provided structural insight in hydrogen bond interactions in the solid state. Principal component analysis allowed the additional identification of correlation trends between structural and physical matrix properties like number of exchangeable protons at the head group, MW, logP, UV-Vis, and sulfatide detection sensitivity. Graphical abstract Design, synthesis and mass spectrometric evaluation of MALDI-MS matrix compound libraries allows the identification of matrix structure - MALDI-MS performance relationships using multivariate statistics as a tool.
Collapse
|
18
|
Knochenmuss R. The Coupled Chemical and Physical Dynamics Model of MALDI. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:365-385. [PMID: 27070182 DOI: 10.1146/annurev-anchem-071015-041750] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The coupled physical and chemical dynamics model of ultraviolet matrix-assisted laser desorption/ionization (MALDI) has reproduced and explained a wide variety of MALDI phenomena. The rationale behind and elements of the model are reviewed, including the photophysics, kinetics, and thermodynamics of primary and secondary reaction steps. Experimental results are compared with model predictions to illustrate the foundations of the model, coupling of ablation and ionization, differences between and commonalities of matrices, secondary charge transfer reactions, ionization in both polarities, fluence and concentration dependencies, and suppression and enhancement effects.
Collapse
Affiliation(s)
- Richard Knochenmuss
- Departement für Chemie und Biochemie, Universität Bern, CH-3012 Bern, Switzerland;
| |
Collapse
|
19
|
Independent assessment of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) sample preparation quality: A novel statistical approach for quality scoring. Anal Chim Acta 2016; 919:1-10. [PMID: 27086093 DOI: 10.1016/j.aca.2016.03.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/17/2016] [Accepted: 03/19/2016] [Indexed: 12/25/2022]
Abstract
Preparation of samples according to an optimized method is crucial for accurate determination of polymer sample characteristics by Matrix-Assisted Laser Desorption Ionization (MALDI) analysis. Sample preparation conditions such as matrix choice, cationization agent, deposition technique or even the deposition volume should be chosen to suit the sample of interest. Many sample preparation protocols have been developed and employed, yet finding the optimal sample preparation protocol remains a challenge. Because an objective comparison between the results of diverse protocols is not possible, "gut-feeling" or "good enough" is often decisive in the search for an optimum. This implies that sub-optimal protocols are used, leading to a loss of mass spectral information quality. To address this problem a novel analytical strategy based on MALDI imaging and statistical data processing was developed in which eight parameters were formulated to objectively quantify the quality of sample deposition and optimal MALDI matrix composition and finally sum up to an overall quality score of the sample deposition. These parameters can be established in a fully automated way using commercially available mass spectrometry imaging instruments without any hardware adjustments. With the newly developed analytical strategy the highest quality MALDI spots were selected, resulting in more reproducible and more valuable spectra for PEG in a variety of matrices. Moreover, our method enables an objective comparison of sample preparation protocols for any analyte and opens up new fields of investigation by presenting MALDI performance data in a clear and concise way.
Collapse
|
20
|
Kirmess KM, Knochenmuss R, Blanchard GJ, Kinsel GR. MALDI ionization mechanisms investigated by comparison of isomers of dihydroxybenzoic acid. JOURNAL OF MASS SPECTROMETRY : JMS 2016; 51:79-85. [PMID: 26757075 DOI: 10.1002/jms.3725] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 10/23/2015] [Accepted: 10/24/2015] [Indexed: 06/05/2023]
Abstract
Matrix-assisted laser desorption/ionization (MALDI) ion formation mechanisms were investigated by comparison of isomers of dihydroxybenzoic acid (DHB). These exhibit substantially different MALDI performance, the basis for which was not previously understood. Luminescence decay curves are used here to estimate excited electronic state properties relevant for the coupled chemical and physical dynamics (CPCD) model. With these estimates, the CPCD predictions for relative total ion and analyte ion yields are in good agreement with the data for the DHB isomers. Predictions of a thermal equilibrium model were also compared and found to be incompatible with the data. Copyright © 2015 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Kristopher M Kirmess
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, IL, 62901, USA
| | | | - Gary J Blanchard
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Gary R Kinsel
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, IL, 62901, USA
| |
Collapse
|
21
|
Nagoshi K, Inatomi K, Osaka I, Takayama M. Photochemical Reactions of Aminonaphthols Caused by Laser Desorption/Ionization. Mass Spectrom (Tokyo) 2016; 5:A0048. [DOI: 10.5702/massspectrometry.a0048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/30/2016] [Indexed: 11/23/2022] Open
Affiliation(s)
- Keishiro Nagoshi
- Mass Spectrometry Laboratory, Graduate School of Nanobioscience, Yokohama City University
| | - Kazuma Inatomi
- Mass Spectrometry Laboratory, Graduate School of Nanobioscience, Yokohama City University
| | - Issey Osaka
- Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology
| | - Mitsuo Takayama
- Mass Spectrometry Laboratory, Graduate School of Nanobioscience, Yokohama City University
| |
Collapse
|
22
|
Knochenmuss R. Ion Yields in the Coupled Chemical and Physical Dynamics Model of Matrix-Assisted Laser Desorption/Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1645-1648. [PMID: 26265040 DOI: 10.1007/s13361-015-1225-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/20/2015] [Accepted: 06/21/2015] [Indexed: 06/04/2023]
Abstract
The Coupled Chemical and Physical Dynamics (CPCD) model of matrix assisted laser desorption ionization has been restricted to relative rather than absolute yield comparisons because the rate constant for one step in the model was not accurately known. Recent measurements are used to constrain this constant, leading to good agreement with experimental yield versus fluence data for 2,5-dihydroxybenzoic acid. Parameters for alpha-cyano-4-hydroxycinnamic acid are also estimated, including contributions from a possible triplet state. The results are compared with the polar fluid model, the CPCD is found to give better agreement with the data.
Collapse
|
23
|
Cobice DF, Goodwin RJA, Andren PE, Nilsson A, Mackay CL, Andrew R. Future technology insight: mass spectrometry imaging as a tool in drug research and development. Br J Pharmacol 2015; 172:3266-83. [PMID: 25766375 DOI: 10.1111/bph.13135] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 02/09/2015] [Accepted: 03/03/2015] [Indexed: 12/14/2022] Open
Abstract
In pharmaceutical research, understanding the biodistribution, accumulation and metabolism of drugs in tissue plays a key role during drug discovery and development. In particular, information regarding pharmacokinetics, pharmacodynamics and transport properties of compounds in tissues is crucial during early screening. Historically, the abundance and distribution of drugs have been assessed by well-established techniques such as quantitative whole-body autoradiography (WBA) or tissue homogenization with LC/MS analysis. However, WBA does not distinguish active drug from its metabolites and LC/MS, while highly sensitive, does not report spatial distribution. Mass spectrometry imaging (MSI) can discriminate drug and its metabolites and endogenous compounds, while simultaneously reporting their distribution. MSI data are influencing drug development and currently used in investigational studies in areas such as compound toxicity. In in vivo studies MSI results may soon be used to support new drug regulatory applications, although clinical trial MSI data will take longer to be validated for incorporation into submissions. We review the current and future applications of MSI, focussing on applications for drug discovery and development, with examples to highlight the impact of this promising technique in early drug screening. Recent sample preparation and analysis methods that enable effective MSI, including quantitative analysis of drugs from tissue sections will be summarized and key aspects of methodological protocols to increase the effectiveness of MSI analysis for previously undetectable targets addressed. These examples highlight how MSI has become a powerful tool in drug research and development and offers great potential in streamlining the drug discovery process.
Collapse
Affiliation(s)
- D F Cobice
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - R J A Goodwin
- Drug Metabolism and Distribution, Mass Spectrometry Imaging, AstraZeneca R&D, Macclesfield, UK
| | - P E Andren
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - A Nilsson
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - C L Mackay
- SIRCAMS, School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - R Andrew
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
24
|
Lu IC, Lee C, Lee YT, Ni CK. Ionization Mechanism of Matrix-Assisted Laser Desorption/Ionization. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2015; 8:21-39. [PMID: 26132345 DOI: 10.1146/annurev-anchem-071114-040315] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In past studies, mistakes in determining the ionization mechanism in matrix-assisted laser desorption/ionization (MALDI) were made because an inappropriate ion-to-neutral ratio was used. The ion-to-neutral ratio of the analyte differs substantially from that of the matrix in MALDI. However, these ratios were not carefully distinguished in previous studies. We begin by describing the properties of ion-to-neutral ratios and reviews early experimental measurements. A discussion of the errors committed in previous theoretical studies and a comparison of recent experimental measurements follow. We then describe a thermal proton transfer model and demonstrate how the model appropriately describes ion-to-neutral ratios and the total ion intensity. Arguments raised to challenge thermal ionization are then discussed. We demonstrate how none of the arguments are valid before concluding that thermal proton transfer must play a crucial role in the ionization process of MALDI.
Collapse
Affiliation(s)
- I-Chung Lu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan; , , ,
| | | | | | | |
Collapse
|
25
|
Lin HY, Hsu HC, Lu IC, Hsu KT, Liao CY, Lee YY, Tseng CM, Lee YT, Ni CK. Fluorescence spectroscopy of UV-MALDI matrices and implications of ionization mechanisms. J Chem Phys 2014; 141:164307. [DOI: 10.1063/1.4898372] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hou-Yu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Hsu Chen Hsu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - I-Chung Lu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Kuo-Tung Hsu
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chih-Yu Liao
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Yin-Yu Lee
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chien-Ming Tseng
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yuan-Tseh Lee
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| |
Collapse
|
26
|
Kirmess KM, Knochenmuss R, Blanchard GJ, Kinsel GR. Excited state dynamics in the matrix-assisted laser desorption/ionization matrix 2,4,6-trihydroxyacetophenone: evidence for triplet pooling charge separation reactions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:2134-2140. [PMID: 25156603 DOI: 10.1002/rcm.7000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/25/2014] [Accepted: 07/26/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Excited state pooling reactions are a central part of some models of ultraviolet matrix-assisted laser desorption/ionization (MALDI) mechanisms. Evidence has been found for pooling in several matrix materials, but a recent report of pure exponential fluorescence decay at MALDI-relevant laser fluences suggested that 2,4,6-trihydroxy-acetophenone (THAP) may be an example of a matrix in which pooling does not occur (Lin et al., Rapid Commun. Mass Spectrom. 2014, 28, 77). However, those data were instrumentally limited in dynamic range and signal/noise ratio, and the conclusion does not take into account several aspects of THAP excited state dynamics. METHODS Using time-correlated single photon counting, and absorption and emission spectroscopies, the excited state dynamics of THAP are reexamined. RESULTS Like many other aromatic ketones and acetophenone, isolated THAP molecules undergo very efficient intersystem crossing. No fluorescence is observed in dilute solution. In the solid state, efficient fluorescence reappears, but is non-exponential even at very low excitation intensity. The solvent used for sample preparation was found to have a large effect on the spectra and decay curves. Needle-like crystals seem to be correlated with reduced intersystem crossing. CONCLUSIONS THAP solid state fluorescence is entirely due to intermolecular interactions. Activation of fluorescence, instead of quenching, is a clear indicator of delocalized excited state phenomena in THAP. Contrary to the conclusions of Lin et al., the greatly increased singlet lifetime in the solid state substantially increases the probability that pooling-type reactions are indeed involved in ionization processes. The sensitivity of fluorescence and phosphorescence on sample morphology appears to reflect changes in intermolecular interactions due to crystal packing. Pooling charge separation pathways based on known triplet-triplet ionization reactions of aromatic ketones are proposed.
Collapse
Affiliation(s)
- Kristopher M Kirmess
- Department of Chemistry and Biochemistry, Southern Illinois University at Carbondale, Carbondale, IL, 62901, USA
| | | | | | | |
Collapse
|
27
|
Knochenmuss R. Energetics and kinetics of thermal ionization models of MALDI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1521-1527. [PMID: 24912435 DOI: 10.1007/s13361-014-0931-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 04/10/2014] [Accepted: 05/12/2014] [Indexed: 06/03/2023]
Abstract
Thermal models of ultraviolet MALDI ionization based on the polar fluid concept are re-examined. Key components are very high solvating power of the fluidized matrix and consequent low reaction-free energy, attainment of thermal equilibrium in the fluid, and negligible recombination losses. None of these are found to hold in a MALDI event. The reaction-free energy in the hot matrix must be near the gas phase value, ion formation is too slow to approach equilibrium, and geminate recombination of autoprotolysis pairs greatly increases the initial loss rate. The maximum thermal ion yield is estimated to be many orders of magnitude below experimental values.
Collapse
|
28
|
Recent methodological advances in MALDI mass spectrometry. Anal Bioanal Chem 2014; 406:2261-78. [PMID: 24652146 DOI: 10.1007/s00216-014-7646-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used for characterization of large, thermally labile biomolecules. Advantages of this analytical technique are high sensitivity, robustness, high-throughput capacity, and applicability to a wide range of compound classes. For some years, MALDI-MS has also been increasingly used for mass spectrometric imaging as well as in other areas of clinical research. Recently, several new concepts have been presented that have the potential to further advance the performance characteristics of MALDI. Among these innovations are novel matrices with low proton affinities for particularly efficient protonation of analyte molecules, use of wavelength-tunable lasers to achieve optimum excitation conditions, and use of liquid matrices for improved quantification. Instrumental modifications have also made possible MALDI-MS imaging with cellular resolution as well as an efficient generation of multiply charged MALDI ions by use of heated vacuum interfaces. This article reviews these recent innovations and gives the author's personal outlook of possible future developments.
Collapse
|
29
|
Diologent L, Franck J, Wisztorski M, Treizebre A, Focsa C, Fournier I, Ziskind M. On the Origin of Increased Sensitivity and Mass Resolution Using Silicon Masks in MALDI. Anal Chem 2014; 86:1404-13. [DOI: 10.1021/ac401329r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Laurent Diologent
- Laboratoire de
Spectrométrie de Masse Biologique Fondamentale et Appliquée
- EA 4550, Bât SN3, Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
- Laboratoire
de Physique des Lasers, Atomes et Molécules - CNRS UMR 8523, Bât P5,Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Julien Franck
- Laboratoire de
Spectrométrie de Masse Biologique Fondamentale et Appliquée
- EA 4550, Bât SN3, Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Maxence Wisztorski
- Laboratoire de
Spectrométrie de Masse Biologique Fondamentale et Appliquée
- EA 4550, Bât SN3, Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Anthony Treizebre
- Institute of Electronics,
Microelectronics and Nanotechnology - UMR-CNRS 8520, Université Lille 1, F59655 Villeneuve d’Ascq, France
| | - Cristian Focsa
- Laboratoire
de Physique des Lasers, Atomes et Molécules - CNRS UMR 8523, Bât P5,Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Isabelle Fournier
- Laboratoire de
Spectrométrie de Masse Biologique Fondamentale et Appliquée
- EA 4550, Bât SN3, Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Michael Ziskind
- Laboratoire
de Physique des Lasers, Atomes et Molécules - CNRS UMR 8523, Bât P5,Université Lille 1, F-59655 Villeneuve
d’Ascq Cedex, France
| |
Collapse
|
30
|
Monopoli A, Calvano CD, Nacci A, Palmisano F. Boronic acid chemistry in MALDI MS: a step forward in designing a reactive matrix with molecular recognition capabilities. Chem Commun (Camb) 2014; 50:4322-4. [DOI: 10.1039/c4cc01185f] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|