Analyte distributions in MALDI samples using MALDI imaging mass spectrometry

Qiao, Hui; Piyadasa, C. K. G.; Spicer, Victor; Ens, Werner

doi:10.1016/j.ijms.2008.11.015

Cited by 22 publications

(23 citation statements)

References 32 publications

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“…These data suggest that the DHB crystal may have grown from bottom to top and right to left and that the hydrophilic vasopressin was preferentially incorporated first. Generally, the hydrophobicity of analyte and matrix, the solvent composition, the mass of the analyte, and the speed of the crystallization will all influence fine details of the incorporation [15]. The observation of these segregation effects between peptides with different hydrophobicities in a DHB crystal is in agreement with the previous MALDI-MSI studies that incorporated the same or similar analytes into the matrices [14,15].…”

Section: Segregation Effectssupporting

confidence: 87%

“…A very minor decline of both signals (within a factor of 2-3) with increasing sputter time is probably caused by the changes in the matrix diameter, or possibly some spatial segregation effect, rather than by an Ar beam-induced degradation of matrix or analytes. This differentiates the method from the MALDI analysis of cinnamic acid derivatives, where laser-induced thermal-/photochemical modifications degrade the matrix performance [15][16][17][18][19]. Figure 2 shows the 2D distribution of bradykinin across the initial top crystal surface and at approximately 1/3 depth.…”

Section: Integral Depth Profilesmentioning

confidence: 99%

“…For example, Spengler and Hubert [13], and Bouschen and Spengler [14] used scanning microprobe MALDI-MS imaging to visualize the peptide distribution in surface areas of 2,5-dihydroxybenzoic acid (DHB) matrix crystals with a lateral resolution of~1 μm, and Qiao et al investigated-next to DHB preparations-two common cinnamic acid derivative matrices, α-cyano-4-hydroxy cinnamic acid (HCCA) and sinapic acid with a 10 μm-wide laser beam [15]. Both the Spengler and the Ens groups also explored the potential of their method for recording 3D profiles of the analyte distributions.…”

Section: Introductionmentioning

confidence: 99%

“…This has been attributed to laser-induced thermal and photochemical modifications of the matrix compounds [18,19]. Despite these limitations, the above MALDI-MS imaging studies clearly indicated the occurrence of analyte segregation within the analytematrix crystals; in particular the hydrophobicity of a compound seems to affect the overall co-crystallization process [14,15]. Not least of such effects can have implications for MALDI-MS imaging and quantitative MALDI-MS analyses, because they can potentially affect the total ion signals obtained from a given pixel and within a given number of laser shots.…”

Section: Introductionmentioning

confidence: 99%

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3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution

Körsgen

Pelster

Dreisewerd

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. The analytical sensitivity in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is largely affected by the specific analyte-matrix interaction, in particular by the possible incorporation of the analytes into crystalline MALDI matrices. Here we used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to visualize the incorporation of three peptides with different hydrophobicities, bradykinin, Substance P, and vasopressin, into two classic MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (HCCA). For depth profiling, an Ar cluster ion beam was used to gradually sputter through the matrix crystals without causing significant degradation of matrix or biomolecules. A pulsed Bi 3 ion cluster beam was used to image the lateral analyte distribution in the center of the sputter crater. Using this dual beam technique, the 3D distribution of the analytes and spatial segregation effects within the matrix crystals were imaged with sub-μm resolution. The technique could in the future enable matrix-enhanced (ME)-ToF-SIMS imaging of peptides in tissue slices at ultra-high resolution.

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Section: Segregation Effectssupporting

confidence: 87%

Section: Integral Depth Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution

Körsgen

Pelster

Dreisewerd

et al. 2015

J. Am. Soc. Mass Spectrom.

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“…8) On the other hand, to the contrary, several mass spectrometric imaging studies have clearly demonstrated the inhomogeneous distribution of analyte molecules in 2,5-DHBA crystals. [9][10][11][12] In particular, Bouschen & Spengler 11) and Qiao et al 12) used MALDI imaging at better than a 10 μm spatial resolution to investigate analyte distribution and showed that analytes were segregated in small DHBA crystals in dried-droplet preparations. Such an uneven distribution of analyte would be directly related to the observed signal inhomogeneity.…”

Section: Introductionmentioning

confidence: 99%

Correlation between Sweet Spots of Glycopeptides and Polymorphism of the Matrix Crystal in MALDI Samples

Nishikaze¹,

Okumura²,

Jinmei³

et al. 2012

Mass Spectrometry

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A standard dried-droplet preparation using 2,5-dihydroxybenzoic acid (2,5-DHBA) as the matrix results in a large variation in signal intensity and poor shot-to-shot reproducibility in matrix-assisted laser desorption/ionization (MALDI). We expected that the di erences can be attributed to the nature of the crystal structures in the region of the "sweet spot" within the MALDI samples. 2,5-DHBA crystals with and without analytes on a target plate obtained by means of a dried-droplet preparation contain two polymorphs, which can be distinguished by Raman spectra. In comparing the Raman image with the MS image, a clear correlation between the signal distribution of glycopeptides and hydrophilic peptides and the speci c crystal form of 2,5-DHBA could be made. e ionization of hydrophobic peptides appears to proceed in both types of polymorphic crystals. In addition, the derivatization of glycopeptides with a pyrene group enabled us to detect glycopeptides regardless the crystal form. As the result, the number of sweet spots increased and MS spectra with a high signal intensity were obtained. e results suggest that the introduction of a hydrophobic/aromatic moiety to glycopeptides results in a more successful MALDI analysis due to the e ective incorporation of the analyte into matrix crystals.

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