Factors affecting the resolution in matrix-assisted laser desorption—ionization mass spectrometry

Ingendoh, Arnd; Karas, Michael; Hillenkamp, Franz; Giessmann, U.

doi:10.1016/0168-1176(93)03873-k

Cited by 61 publications

(35 citation statements)

References 31 publications

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“…In particular, we look at some physical factors that affect the mass resolution (Ingendoh et al, 1994; Barbacci et al, 1997, Vestal and Juhasz, 1998), at limits on the accuracy of mass calibration (Christian et al, 2000; Hack and Benner, 2002), at the role of isotope distributions (Zhang et al, 1997), and at implications for the normalization and quantification of MALDI-TOF data.…”

Section: Resultsmentioning

confidence: 99%

Understanding the Characteristics of Mass Spectrometry Data through the use of Simulation

et al. 2005

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Abstract:Background: Mass spectrometry is actively being used to discover disease-related proteomic patterns in complex mixtures of proteins derived from tissue samples or from easily obtained biological fluids. The potential importance of these clinical applications has made the development of better methods for processing and analyzing the data an active area of research. It is, however, difficult to determine which methods are better without knowing the true biochemical composition of the samples used in the experiments. Methods: We developed a mathematical model based on the physics of a simple MALDI-TOF mass spectrometer with time-lag focusing. Using this model, we implemented a statistical simulation of mass spectra. We used the simulation to explore some of the basic operating characteristics of MALDI or SELDI instruments. Results: The simulation reproduced several characteristics of actual instruments. We found that the relative mass error is affected by the time discretization of the detector (about 0.01%) and the spread of initial velocities (about 0.1%). The accuracy of calibration based on external standards decays rapidly outside the range spanned by the calibrants. Natural isotope distributions play a major role in broadening peaks associated with individual proteins. The area of a peak is a more accurate measure of its size than the height. Conclusions: The model described here is capable of simulating realistic mass spectra. The simulation should become a useful tool for generating spectra where the true inputs are known, allowing researchers to evaluate the performance of new methods for processing and analyzing mass spectra. Availability: http://bioinformatics.mdanderson.org/cromwell.html

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Section: Resultsmentioning

confidence: 99%

Understanding the Characteristics of Mass Spectrometry Data through the use of Simulation

et al. 2005

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“…Unfortunately, the shortage of comprehensive knowledge about ionization mechanisms makes MALDI a highly empirical method [2]. Changes in both sample preparation protocols [3][4][5] and photoexcitation parameters [6][7][8][9] critically influence the quality of resulted mass spectra.…”

Section: Introductionmentioning

confidence: 99%

Desorption dynamics of neutral molecules in matrix-assisted laser desorption/ionization

Tsai¹,

Chen²,

Lee³

et al. 2008

Molecular Physics

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This work studies the expansion dynamics of molecules ejected from sample crystals in matrix-assisted laser desorption/ionization (MALDI) reaction. Measurements were made in two steps -sample desorption using a 355 nm pulsed laser beam and gas-phase postionization using a 266 nm laser at various delays. The estimated ion production yield is approximately 10 4 times better than that obtained using conventional MALDI methods. A model system of co-crystallized tryptophan (Trp) analyte and 2,4,6-trihydroxyacetophenone (THAP) matrix yielded overlapping time-of-arrival profiles. This result suggests that translational behaviours of gas-phase Trp and THAP are thermalized during expansion. The observed plume velocity depends strongly on the matrix and analyte composition: the most probable velocity is 214 m/s for pure Trp and 450 m/s for pure THAP. The incorporation of Trp into THAP makes both their velocities fall between the two extreme cases. Multiple half-space Maxwellian curves adequately describe the observed desorption velocity profile, implying that MALDI consists of multiple desorption components.

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“…Thus an ideal internal standard would be an isotopically labeled analog of the analyte. However, insufficient mass resolution of the TOF instrument [16,[24][25][26] and metastable ion decay [15] does not allow one to use such an internal standard in practice. So what is generally used is a compromise between these requirements [23].…”

Section: Resultsmentioning

confidence: 99%

“…Sample preparation, matrix crystallization and the conditions of the substrate surface lead to poor intra and inter sample signal reproducibility. In addition low efficiency of the detector ion-to-electron conversion [14], metastable decay in time-of-flight (TOF) instruments [15] and formation of matrix and cationized adducts inducing poor MALDI resolution [16] and sensitivity, all cause both systematic and random measurement errors. Quantitative measurements require a highly linear data acquisition system.…”

Section: Introductionmentioning

confidence: 99%

Direct quantitative analysis of peptides using matrix assisted laser desorption ionization

Gusev

Wilkinson

Proctor

et al. 1996

Analytical and Bioanalytical Chemistry

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The protocol and various matrices were examined for quantification of biomolecules in both the low ca. 1200 amu and mid mass 6000-12000 amu ranges using an internal standard. Comparative studies of different matrices of MALDI quantitative analysis showed that the best accuracy and standard curve linearity were obtained for two matrices: (a) 2,5-dihydroxybenzoic acid (DHB) combined with a comatrix of fucose and 5-methoxysalicylic acid (MSA) and (b) ferulic acid/fucose. In the low mass range, the quantitative limit was in the 30 fmol range and in the mid mass range the quantitative limit was in the 250 fmol range. Linear response was observed over 2-3 decades of analyte concentration. The relative error of the standard curve slope was 1.3-1.8% with correlation coefficients of 0.996-0.998.The main problem for quantitative measurement was suppression of the signal of the less concentrated component (analyte or internal standard) by the more concentrated component. The effect was identified with saturation of the matrix by the analyte. The threshold of matrix saturation was found to be in the range of 1/(3000-5000) analyte/matrix molar ratio. To avoid matrix saturation the (analyte+internal standard) to matrix molar ratio should be below this threshold. Thus the internal standard concentration should be as low as possible.DHB/MSA/fucose and ferulic acid/fucose matrices demonstrated good accuracy and linearity for standard curves even when the internal standard had chemical properties different from the analyte. However, use of an internal standard with different chemical properties requires highly stable instrumental parameters as well as constant (analyte+internal standard)/matrix molar ratio for all samples.

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Factors affecting the resolution in matrix-assisted laser desorption—ionization mass spectrometry

Cited by 61 publications

References 31 publications

Understanding the Characteristics of Mass Spectrometry Data through the use of Simulation

Understanding the Characteristics of Mass Spectrometry Data through the use of Simulation

Desorption dynamics of neutral molecules in matrix-assisted laser desorption/ionization

Direct quantitative analysis of peptides using matrix assisted laser desorption ionization

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