Fundamentals of matrix-assisted laser desorption/ionization mass spectrometry with pulsed infrared lasers

Dreisewerd, Klaus; Berkenkamp, Stefan; Leisner, Arne; Rohlfing, Andreas; Menzel, Christoph

doi:10.1016/s1387-3806(02)00977-6

Cited by 112 publications

(117 citation statements)

References 57 publications

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“…In contrast, the greater material removal of IR lasers is an advantage for ambient ionization techniques such as MALDESI and the related LAESI technique [19][20][21]. The volumetric energy deposition with a mid-IR laser is comparable to that of UV lasers, but the depth of laser penetration is an order of magnitude larger [22]. The greater penetration depth of IR lasers can be an advantage in removing deeply embedded materials such as biomolecules in polyacrylimide gels [23,24] and in tissue samples [25].…”

Section: Introductionmentioning

confidence: 99%

Infrared Laser Ablation Sample Transfer for MALDI and Electrospray

Park

Murray

2011

J. Am. Soc. Mass Spectrom.

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We have used an infrared laser to ablate materials under ambient conditions that were captured in solvent droplets. The droplets were either deposited on a MALDI target for off-line analysis by MALDI time-of-flight mass spectrometry or flow-injected into a nanoelectrospray source of an ion trap mass spectrometer. An infrared optical parametric oscillator (OPO) laser system at 2.94 μm wavelength and approximately 1 mJ pulse energy was focused onto samples for ablation at atmospheric pressure. The ablated material was captured in a solvent droplet 1-2 mm in diameter that was suspended from a silica capillary a few millimeters above the sample target. Once the sample was transferred to the droplet by ablation, the droplet was deposited on a MALDI target. A saturated matrix solution was added to the deposited sample, or in some cases, the suspended capture droplet contained the matrix. Peptide and protein standards were used to assess the effects of the number of IR laser ablation shots, sample to droplet distance, capture droplet size, droplet solvent, and laser pulse energy. Droplet collected samples were also injected into a nanoelectrospray source of an ion trap mass spectrometer with a 500 nL injection loop. It is estimated that pmol quantities of material were transferred to the droplet with an efficiency of approximately 1%. The direct analysis of biological fluids for off-line MALDI and electrospray was demonstrated with blood, milk, and egg. The implications of this IR ablation sample transfer approach for ambient imaging are discussed.

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Section: Introductionmentioning

confidence: 99%

Infrared Laser Ablation Sample Transfer for MALDI and Electrospray

Park

Murray

2011

J. Am. Soc. Mass Spectrom.

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“…These observations are reminiscent of studies of IR-MALDI using glycerol as a matrix where resolution characteristics typically two to three times lower than solid state matrices were observed. There, the poor resolution has been attributed to changes in plume dynamics [24] and thus, in our case, a similar effect may have occurred when the quantity of glycerol present increased.…”

Section: The Role Of a Surface Tension Modifier On Sample Spot Preparmentioning

confidence: 50%

“…Collections of droplets (1,24,50, and 100) prepared by rapid deposition from a methanol solution containing 10 M lysozyme and 0.9% glycerol (Solution II) were analyzed and compared to a sample of the same solution prepared as a 0.5 L dried droplet ( Figure 5). Using the same laser power setting, the ion signals detected from consecutive sets of eight laser shots were averaged to produce the mass spectra shown.…”

Section: The Role Of Multiple Droplet Co-depositionmentioning

confidence: 99%

“…The most intriguing set of candidates at this point is the suite of ionic liquid matrices for MALDI that were recently introduced [27]. Alternatively, glycerol is commonly used as a matrix for IR-MALDI [24], suggesting another avenue of future application for m-sized glycerol containing sample spots created by WaSP.…”

Section: Detection Of Fmol Quantities Of a Peptide Or Protein From M-mentioning

confidence: 99%

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Wall-less sample preparation of μm-sized sample spots for femtomole detection limits of proteins from liquid based UV-MALDI matrices

Bogan

Agnes

2004

J. Am. Soc. Mass Spectrom.

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Previously, we introduced wall-less sample preparation (WaSP), technology that involves the use of an electrodynamic balance (EDB) to prepare m-sized sample spots for analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In that work we demonstrated the detection of femtomole quantities of a low molecular weight peptide and a hydrophobic ester (both Ͻ600 Da). Here we use WaSP to test the hypothesis that the use of small sample spot sizes and an instrument equipped with delayed extraction would increase the analytical utility of liquid sample spots for peptide and protein (Ͼ2500 Da) analysis by UV-MALDI-TOF-MS (Sze et al.; J. Am. Soc. Mass Spectrom. 1998, 9, 166 -174). To aid the optimization of preparing m-sized sample spots by WaSP, optical microscopy and mass spectrometry were used to investigate nonvolatile solute concentration effects on droplet fission and sample spot size, modifications of the EDB electric field to control droplet ejection, and the use of multiple droplet deposition to increase sample loading. Also described is a rapid deposition mode of operation for WaSP that allows single droplets generated at 1 Hz to be levitated briefly (ϳ500 ms) before being ejected autonomously and deposited as a concentrated sample spot with a spatial accuracy of Ϯ5 m. To test the sensitivity of the method, one hundred glycerol droplets (270 pL each, 27 nL total) each containing 32 amol lysozyme were deposited on top of each other one-at-a-time to create a single sample spot. Using a mass spectrometer equipped with delayed extraction to analyze this sample spot, we verified the hypothesis of Sze et al. by achieving detection limits three orders of magnitude below that previously observed for the detection of a protein by UV-MALDI-TOF-MS with a chemical-doped liquid matrix sample preparation. (J Am Soc Mass Spectrom 2004, 15, 486 -495)

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“…Over the last three decades, fundamental ionization mechanisms have been systematically studied by manipulating one or more parameters among di erent matrix systems. 22,35) E ects of the incorporation of analytes into matrix solid, [36][37][38][39][40] matrix-to-analyte ratio, 41,42) solvent constituents, [43][44][45][46][47] laser excitation conditions, 22,48,49) and the crystal morphology of samples 47,[50][51][52][53][54][55] on ion production were investigated. A prerequisite of successful MALDI processes is absorption of laser energy by matrices.…”

Section: Ion Production In Maldimentioning

confidence: 99%

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry: Mechanistic Studies and Methods for Improving the Structural Identification of Carbohydrates

Lai

Wang

2017

Mass Spectrometry

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Although matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is one of the most widely used so ionization methods for biomolecules, the lack of detailed understanding of ionization mechanisms restricts its application in the analysis of carbohydrates. Structural identi cation of carbohydrates achieved by MALDI mass spectrometry helps us to gain insights into biological functions and pathogenesis of disease. In this review, we highlight mechanistic details of MALDI, including both ionization and desorption. Strategies to improve the ion yield of carbohydrates are also reviewed. Furthermore, commonly used fragmentation methods to identify the structure are discussed.

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Fundamentals of matrix-assisted laser desorption/ionization mass spectrometry with pulsed infrared lasers

Cited by 112 publications

References 57 publications

Infrared Laser Ablation Sample Transfer for MALDI and Electrospray

Infrared Laser Ablation Sample Transfer for MALDI and Electrospray

Wall-less sample preparation of μm-sized sample spots for femtomole detection limits of proteins from liquid based UV-MALDI matrices

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry: Mechanistic Studies and Methods for Improving the Structural Identification of Carbohydrates

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