Laser desorption mass spectrometry with thermospray sample deposition for determination of nonvolatile biomolecules

Hardin, E. D.; Fan, Terry; Blakley, C. R.; Vestal, Marvin L.

doi:10.1021/ac00265a003

Cited by 53 publications

(12 citation statements)

References 25 publications

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“…Vestal and coworkers reported that non-resonant desorption/ionization of non-volatile compounds led to a dominance of alkali cationized species over protonated ones. 27,28 In practical MALDI experiments, the two processes usually coexist and compete. The competition between protonation and cationization is evident in the so-called 'matrix suppression effect'.…”

Section: Introductionmentioning

confidence: 99%

Matrix‐dependent cationization in MALDI mass spectrometry

Zhang¹,

Zenobi²

2004

J. Mass Spectrom.

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The matrix dependence in cationization processes, the competition between cationization and protonation and the question of whether gas-phase cation transfer or attachment of free cations dominates in matrix-assisted laser desorption/ionization mass spectrometry were studied. Two different sample preparation methods were employed, the dried-droplet sample preparation and a mixture of solid matrix, analyte and salt. The latter ensures that the formation of cation adducts takes place in the gas phase. By monitoring the suppression of matrix signals for different matrices, it was found that matrices with high gas-phase metal ion binding energies require high analyte concentrations for matrix suppression to occur. By comparing the mass spectra obtained using sinapinic acid or sinapinic methyl ester as a matrix, a correlation between cationization and deprotonation of matrix molecules was found. It is also demonstrated that attachment of free gas-phase cations, rather than cation transfer from the cationized matrix, is the predominant process in cationization.

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Section: Introductionmentioning

confidence: 99%

Matrix‐dependent cationization in MALDI mass spectrometry

Zhang¹,

Zenobi²

2004

J. Mass Spectrom.

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“…Namely: fast atom bombardment (FAB) [1], field desorption (FD) [2], laser desorption (LD) [3], plasma desorption mass spectrometry (PDMS) [4] and secondary ion mass spectrometry (SIMS) [5]. In spite of the significant improvement and extended applicability of these methods they all suffer of the same limitation derived from the fact that both desorption and ionisation cannot be separately optimised, which, obviously, may be critical for many real applications.…”

mentioning

confidence: 99%

Non-volatile analysis in fruits by laser resonant ionization spectrometry: application to resveratrol (3,5,4′-trihydroxystilbene) in grapes

Montero

Orea

Muñoz

et al. 2000

Applied Physics B: Lasers and Optics

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Abstract.A laser desorption (LD) coupled with resonanceenhanced multiphoton ionisation (REMPI) and time-of-flight mass spectrometry (TOFMS) technique for non-volatile trace analysis compounds is presented. Essential features are: (a) an enhanced desorption yield due to the mixing of metal powder with the analyte in the sample preparation, (b) a high resolution, great sensitivity and low detection limit due to laser resonant ionisation and mass spectrometry detection. Application to resveratrol content in grapes demonstrated the capability of the analytical method with a sensitivity of 0.2 pg per single laser shot and a detection limit of 5 ppb. 42.62.Fi; 82.80.Ms One of the crucial problems in the development of new analytical methods, specially in the case of food samples, is the detection and identification of non-volatile organic compounds present at low concentration levels. Although mass spectrometry nowadays is widely used in the analysis of such compounds providing exact mass identification, the difficulty lies in their volatilisation into the gas phase prior to injection into the analyser. This first-step requirement is particularly a problem for thermally labile samples as they rapidly decompose upon heating. PACS:To circumvent this difficulty a wide range of techniques have been developed for non-volatile analysis. Namely:, plasma desorption mass spectrometry (PDMS) [4] and secondary ion mass spectrometry (SIMS) [5]. In spite of the significant improvement and extended applicability of these methods they all suffer of the same limitation derived from the fact that both desorption and ionisation cannot be separately optimised, which, obviously, may be critical for many real applications. matrix-assisted laser desorption/ionisation (MALDI) technique is widely used for ion generation in many mass spectrometric analytical applications [6]. This is accomplished by mixing the analyte with an excess of cromophore matrix so as to improve both the desorption and ionisation processes, especially in the case of protein and polymer analysis. However, due to the complexity of the process, finding the best cromophore or matrix for a particular analyte is not always straightforward. A significant improvement using the MALDI technique was obtained by the so-called ultra fine metal plus liquid matrix method (UFP) for sample preparation [7]. This procedure increases the yield of high-mass ions and prolongs their production time.More recently, laser desorption methods have been developed in which volatilisation and ionisation steps are separated and so higher sample sensitivity is achieved. While all them have in common the laser desorption step they differ in their ionisation method. Within this category the laser multiphoton ionisation coupled with time-of-flight mass spectrometry, and in particular resonance-enhanced multiphoton ionisation (REMPI)-time-of-flight mass spectrometry (TOFMS) can be considered as one of the most powerful methods for the analysis of trace components in complex matrix [8][9][10][11][12][1...

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“…Even considered that the terms "thermal" and "equilibrium process" are used with somewhat different meanings by different authors, the fundamental questio remains. Observation of "non volatile", large organic parent molecular ions with relative molecular masses above 1000 [18,21,22,29,31,36)and often very limited fragmentation supports the notion of a nonequilibrium process.Ver little is on the other hand known about the true volatility of most substances investigated and some of the improvements in the range of detected large ions also result from increased sensitivities of the instruments used. The prolonge ion emission over tens of microseconds as reported by COTTER(17, 18J, on the other hand, seems to rather support a therma1 model.…”

Section: Mechanisms Of Laser Desorptionmentioning

confidence: 72%

“…LD had a rather slow start, but considering the limited number of investigators, progress has been quite remarkable nonetheless. A variety of bioorganic molecules with relative molecular masses in the range of 1000-2000 have been detected with all the different techniques [18,21,22,29,31,36] . Fig.…”

Section: Status and Outlookmentioning

confidence: 99%

Laser Desorption Mass Spectrometry. A Review

Hillenkamp

1986

Springer Series in Chemical Physics

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Laser desorption mass spectrometry with thermospray sample deposition for determination of nonvolatile biomolecules

Cited by 53 publications

References 25 publications

Matrix‐dependent cationization in MALDI mass spectrometry

Matrix‐dependent cationization in MALDI mass spectrometry

Non-volatile analysis in fruits by laser resonant ionization spectrometry: application to resveratrol (3,5,4′-trihydroxystilbene) in grapes

Laser Desorption Mass Spectrometry. A Review

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