The effect of counter ions in matrix-assisted laser desorption/ionization of poly(methyl methacrylate)

Hoberg, Anne-Mette; Haddleton, David M.; Derrick, Peter J.; Jackson, Anthony T.; Scrivens, James H.

doi:10.1255/ejms.268

Cited by 43 publications

(42 citation statements)

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“…Reducing the size of the anionic salt component reduces in the present case the cation attachment. Similar findings have been noted for the cationization of polymers [41]. This counter ion effect correlates roughly with the lattice energies of the salt crystals [30].…”

Section: Counter Ion Effectssupporting

confidence: 86%

Alkali cation attachment to derivatized fullerenes studied by matrix-assisted laser desorption/ionization

Fati

Leeman

Vasil’ev

et al. 2002

J. Am. Soc. Mass Spectrom.

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The complexation of alkali metal ions with amphiphilic fullerene derivatives has been investigated by matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry. The formation of analyte ions occurs via two competing mechanisms including electron transfer from matrix-derived ions and metal ion attachment. The interplay of these processes has been examined by laser fluence dependent sample activation and by variation of the target composition. The attachment of metal ions has been established as the gentler and thus more efficient route towards the formation of intact analyte ions. Investigations into the metal ion complexation have been conducted to reveal the reactivity order of the alkali metals in these reactions and to elucidate the influence of structural differences of the analytes, as well as to unravel effects caused by the anionic counter ion of the metal. The experimental data have been derived by two complementary approaches. Competing reactants were either studied simultaneously, so that the product distribution would provide direct insight into the reactivity pattern, and/or product distributions were obtained in a large variety of separate experiments and normalized for reliable comparison. It has been found that the extent to which complexation is observed follows the charge density order of the alkali metal ions. The structural features of the fullerene-attached ligands were of profound influence on the attachment of the metal ion, inducing enhanced selectivity for the complexation with less reactive metals. The metal ion attachment is reduced with the use of smaller anionic counter ions. Rationalization of these findings is provided within the framework of the mechanisms of ion formation in

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Section: Counter Ion Effectssupporting

confidence: 86%

Alkali cation attachment to derivatized fullerenes studied by matrix-assisted laser desorption/ionization

Fati

Leeman

Vasil’ev

et al. 2002

J. Am. Soc. Mass Spectrom.

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“…The preference for Li þ attachment to matrix and analyte was also found for other porphyrin matrices. Hoberg et al (1998) showed that, when an alkali-metal cationization strategy is pursued with alkalihalide salts, a halide counter anion should be chosen that results in the lowest lattice energy of the alkalihalide salt. For example, when cationization with sodium is pursued, more abundant sodiated signals for the analyte are observed when sodium iodide is used as the cationizing agent compared to sodium chloride.…”

Section: A Protonation Versus Cationizationmentioning

confidence: 99%

Biomedical application of MALDI mass spectrometry for small‐molecule analysis

Kampen

Burgers

Groot

et al. 2010

Mass Spectrometry Reviews

136

102

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Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is an emerging analytical tool for the analysis of molecules with molar masses below 1,000 Da; that is, small molecules. This technique offers rapid analysis, high sensitivity, low sample consumption, a relative high tolerance towards salts and buffers, and the possibility to store sample on the target plate. The successful application of the technique is, however, hampered by low molecular weight (LMW) matrix-derived interference signals and by poor reproducibility of signal intensities during quantitative analyses. In this review, we focus on the biomedical application of MALDI-MS for the analysis of small molecules and discuss its favorable properties and its challenges as well as strategies to improve the performance of the technique. Furthermore, practical aspects and applications are presented.

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“…PEG ions resulting from these distributions should be expected to have the same ionization efficiency and would logically be detected in similar abundance. However, in practice it is difficult to obtain such a result due to the influence of various factors such as matrix concentration, [19 -21] sample morphology, [22] crystallite size, [23] buffer type, [24,25] laser energy, [26] delayed extraction, [27] cation choice, [28,29], and laser fluence [30 -32]. Figure 1 contains MALDI-FTMS spectra obtained for an equimolar mixture of PEG 2K, 4K, 6K, and 8K as a function of relative amount of DHB matrix added.…”

Section: Resultsmentioning

confidence: 99%

Trapping of wide range mass-to-charge ions and dependence on matrix amount in internal source MALDI-FTMS

Jaber

Kaufman

Liyanage

et al. 2005

J. Am. Soc. Mass Spectrom.

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The effect of counter ions in matrix-assisted laser desorption/ionization of poly(methyl methacrylate)

Cited by 43 publications

References 0 publications

Alkali cation attachment to derivatized fullerenes studied by matrix-assisted laser desorption/ionization

Alkali cation attachment to derivatized fullerenes studied by matrix-assisted laser desorption/ionization

Biomedical application of MALDI mass spectrometry for small‐molecule analysis

Trapping of wide range mass-to-charge ions and dependence on matrix amount in internal source MALDI-FTMS

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