Abstract
Electrosprayed spots of varying thickness were evaluated for use as reproducible, homogenous, high efficiency MALDI samples. Thin samples on stainless steel plates were found to give exceptionally strong signals, as did the last layers of thick samples, when ablated down to the steel substrate. A small enhancement was also observed for thin samples on a gold substrate, and with a few-nanometer gold coating on top of a thick sample. Ion yields and intensity ratios can be understood in the context of the previously described quantitative MALDI model including the matrix-metal interfacial ionization potential reduction effect (Knochenmuss, R.; Anal. Chem. 2004, 76, 3179–3184). The absolute and relative stabilities of ion signals were found to be at least a factor of two better for the thin electrosprayed spots, compared to spots prepared by dried droplet methods.
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Karas, M.; Bachmann, D.; Bähr, U.; Hillenkamp, F. Matrix-Assisted Ultraviolet Laser Desorption of Nonvolatile Compounds. Int. J. Mass Spectrom. Ion Processes 1987, 78, 53–68.
Knochenmuss, R. A Quantitative Model of Ultraviolet Matrix-Assisted Laser Desorption and Ionization. J. Mass Spectrom 2002, 37, 867–877.
Knochenmuss, R. A Quantitative Model of UV-MALDI Including Analyte Ion Generation. Anal. Chem. 2003, 75, 2199.
Knochenmuss, R.; Karbach, V.; Wiesli, U.; Breuker, K.; Zenobi, R. The Matrix Suppression Effect in Matrix-Assisted Laser Desorption/Ionization: Application to Negative Ions and Further Characteristics. Rapid Commun. Mass Spectrom 1998, 12, 529–534.
Knochenmuss, R.; Dubois, F.; Dale, M. J.; Zenobi, R. The Matrix Suppression Effect and Ionization Mechanisms in Matrix-Assisted Laser Desorption/Ionization. Rapid Commun. Mass Spectrom 1996, 10, 871–877.
Knochenmuss, R.; Stortelder, A.; Breuker, K.; Zenobi, R. Secondary Ion-Molecule Reactions in MALDI. J. Mass Spectrom 2000, 35, 1237–1245.
McCombie, G.; Knochenmuss, R. Small-Molecule MADI Using the Matrix Suppression Effect to Reduce or Eliminate Matrix Background Interferences. Anal. Chem. 2004, 76, 4990–4997.
Knochenmuss, R. Photoionization Pathways and Free Electrons in UV-MALDI. Anal. Chem. 2004, 76, 3179–3184.
Frankevich, V. E.; Zhang, J.; Friess, S. D.; Dashtiev, M.; Zenobi, R. Role of Electrons in Laser Desorption/Ionization Mass Spectrometry. Anal. Chem. 2003, 75, 6063–6067.
Karas, M.; Glückmann, M.; Schäfer, J. Ionization in MALDI: Singly Charged Molecular Ions are the Lucky Survivors. J. Mass Spectrom 2000, 35, 1–12.
Hensel, R. R.; King, R. C.; Owens, K. G. Electrospray Sample Preparation for Improved Quantitation in Matrix-Assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry. Rapid Commun. Mass Spectrom 1997, 11, 1785–1793.
Axelsson, J.; Hoberg, A.-M.; Waterson, C.; Myatt, P.; Shield, G. L.; Verney, J.; Haddleton, D. M.; Derrick, P. J. Improved Reproducibility and Increased Signal Intensity in Matrix-assisted Laser Desorption/Ionization as a Result of Electrospray Sample Preparation. Rapid Commun. Mass Spectrom 1997, 11, 209–213.
Stoeckli, M.; Staab, D.; Staufenbiel, M.; Wiederhold, K. H.; Signor, L. Molecular Imaging of Amyloid β Peptides in Mouse Brain Sections Using Mass Spectrometry. Anal. Biochem 2002, 311, 33–39.
Schiller, J.; Müller, K.; Süss, R.; Arnhold, J.; Gey, C.; Herrmann, A.; Lessig, J.; Arnold, K.; Müller, P. Analysis of the Lipid Composition of Bull Spermatozoa by MALDI-TOF Mass Spectrometry—A Cautionary Note. Chem. Phys. Lipids 2003, 126, 85–94.
Bligh, E. G.; Dyer, W. J. A Rapid Method of Total Lipid Extraction and Purification. Can. J. Biochem. Phys. 1959, 37, 911–917.
Cohen, L. H.; Strupat, K.; Hillenkamp, F. Analysis of Quaternary Protein Ensembles by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry. J. Am. Soc. Mass Spectrom 1997, 8, 1046–1052.
Sadeghi, M.; Vertes, A. Crystallite Size Dependence of Volatilization in Matrix-Assisted Laser Desorption Ionization. Appl. Surf. Sci. 1998, 127/129, 226–234.
Fournier, I.; Marinach, C.; Tabet, J.-C.; Bolbach, G. Irradiation Effect in MALDI, Ablation, Ion Production, and Surface Modifications. II: 2,5-Dihydroxybenzoic Acid Monocrystals. J. Am. Soc. Mass Spectrom 2003, 14, 893–899.
Garden, R. W.; Sweedler, J. V. Heterogeneity within MALDI Samples as Revealed by Mass Spectrometric Imaging. Anal. Chem. 2000, 72, 30–36.
Gusev, A. I.; Wilkinson, W. R.; Proctor, A.; Hercules, D. M. Improvement of Signal Reproducibility and Matrix/Comatrix Effects in MALDI Analysis. Anal. Chem. 1995, 67, 1034–1041.
Setz, P. D.; Knochenmuss, R. Exciton Mobility and Trapping in a MALDI Matrix. J. Phys. Chem. 2005, 109, 4030–4037.
Knochenmuss, R.; Zenobi, R. MALDI Ionization: The Role of In-Plume Processes. Chem. Rev. 2003, 103, 441–452.
Hoffmann, R. Solids and Surfacesa Chemist’s View of Bonding in Extended Structures; VCH: Weinheim, 1988; p 142.
Scherl, A.; Zimmermann-Ivol, C. G.; Di Dio, J.; Vaezzadeh, A. R.; Binz, P.-A.; Amez-Droz, M.; Cochard, R.; Sanchez, J.-C.; Glueckmann, M.; Hochstrasser, D. F. Gold Coating of Nonconductive Membranes Before Matrix-Assisted Laser Desorption/Ionization Tandem Mass Spectrometric Analysis Prevents Charging Effect. Rapid Commun. Mass Spectrom 2005, 19, 605–610.
Delcorte, A.; Medard, N.; Bertrand, P. Organic Secondary Ion Mass Spectrometry: Sensitivity Enhancement by Gold Deposition. Anal. Chem. 2002, 74, 4955–4968.
Tanaka, K.; Waki, H.; Ido, Y.; Akita, S.; Yoshida, Y.; Yoshida, T. Protein and Polymer Analyses of up to m/z 100,000 by Laser Ionization Time-of-Flight Mass Spectrometry. Rapid Commun. Mass Spectrom 1988, 2, 151–153.
Sunner, J.; Dratz, E.; Chen, Y.-C. Graphite Surface-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry of Peptides and Proteins from Liquid Solutions. Anal. Chem. 1995, 67, 4335–4342.
Horneffer, V.; Dreisewerd, K.; Lüdemann, H.-C.; Hillenkamp, F.; Lage, M.; Strupat, K. Is the Incorporation of Analytes into Matrix Crystals a Prerequisite for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry? A Study of Five Positional Isomers of Dihydroxybenzoic Acid. Int. J. Mass Spectrom 1999, 185/186/187, 859–870.
Allwood, D. A.; Dreyfus, R. W.; Perera, I. K.; Dyer, P. E. UV Optical-Absorption of Matrices Used for Matrix-Assisted Laser Desorption/Ionization. Rapid Commun. Mass Spectrom 1996, 10, 1575–1578.
Karlsson, B.; Ribbing, C. G. Optical Constants and Spectral Selectivity of Stainless Steel and Its Oxides. J. Appl. Phys. 1982, 53, 6340–6346.
Luxembourg, S. L.; McDonnell, L. A.; Duursma, M. C.; Xinghua, G.; Heeren, R. M. A. Effect of Local Matrix Crystal Variations in Matrix-Assisted Ionization Techniques for Mass Spectrometry. Anal. Chem. 2003, 75, 2333–2341.
Karbach, V.; Knochenmuss, R. Do Single Matrix Molecules Generate Primary Ions in Ultraviolet Matrix-Assisted Laser Desorption/Ionization?. Rapid Commun. Mass Spectrom 1998, 12, 968–974.
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Published online March 20, 2006
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McCombie, G., Knochenmuss, R. Enhanced MALDI ionization efficiency at the metal-matrix interface: Practical and mechanistic consequences of sample thickness and preparation method. The official journal of The American Society for Mass Spectrometry 17, 737–745 (2006). https://doi.org/10.1016/j.jasms.2006.02.005
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DOI: https://doi.org/10.1016/j.jasms.2006.02.005