Here you will find all scientific publications from the group leader, Daniel Horke. Articles and materials written for a more general audience can be found on the Outreach pages. Recent posters from the group are in the gallery!
Filter Publications:
2023
4.
Wang S, Dauletyarov Y, Horke D A
High-Throughput UV Photoionization and Fragmentation of Neutral Biomolecules as a Structural Fingerprint Journal Article
In: Molecules, vol. 28, no. 13, pp. 5058, 2023, ISSN: 1420-3049.
Abstract | Links | BibTeX | Altmetric | Tags: LBTD, photofragmentation
@article{molecules28135058,
title = {High-Throughput UV Photoionization and Fragmentation of Neutral Biomolecules as a Structural Fingerprint},
author = {Siwen Wang and Yerbolat Dauletyarov and Daniel A. Horke},
doi = {10.3390/molecules28135058},
issn = {1420-3049},
year = {2023},
date = {2023-06-28},
urldate = {2023-06-28},
journal = {Molecules},
volume = {28},
number = {13},
pages = {5058},
abstract = {We present UV photofragmentation studies of the structural isomers paracetamol, 3-Pyridinepropionic acid (3-PPIA) and (R)-(-)-2-Phenylglycine. In particular, we utilized a new laser-based thermal desorption source in combination with femtosecond multiphoton ionization at 343 nm and 257 nm. The continuous nature of our molecule source, combined with the 50 kHz repetition rate of the laser, allowed us to perform these experiments at high throughput. In particular, we present detailed laser intensity dependence studies at both wavelengths, producing 2D mass spectra with highly differential information about the underlying fragmentation processes. We show that UV photofragmentation produces highly isomer-specific mass spectra, and assign all major fragmentation pathways observed. The intensity-dependence measurements, furthermore, allowed us to evaluate the appearance intensities for each fragmentation channel, which helped to distinguish competing from consecutive fragmentation pathways.},
keywords = {LBTD, photofragmentation},
pubstate = {published},
tppubtype = {article}
}
We present UV photofragmentation studies of the structural isomers paracetamol, 3-Pyridinepropionic acid (3-PPIA) and (R)-(-)-2-Phenylglycine. In particular, we utilized a new laser-based thermal desorption source in combination with femtosecond multiphoton ionization at 343 nm and 257 nm. The continuous nature of our molecule source, combined with the 50 kHz repetition rate of the laser, allowed us to perform these experiments at high throughput. In particular, we present detailed laser intensity dependence studies at both wavelengths, producing 2D mass spectra with highly differential information about the underlying fragmentation processes. We show that UV photofragmentation produces highly isomer-specific mass spectra, and assign all major fragmentation pathways observed. The intensity-dependence measurements, furthermore, allowed us to evaluate the appearance intensities for each fragmentation channel, which helped to distinguish competing from consecutive fragmentation pathways.
3.
Dauletyarov Y, Wang S, Horke D A
Vaporization of Intact Neutral Biomolecules Using Laser-Based Thermal Desorption Journal Article
In: J. Am. Soc. Mass Spectrom., vol. 34, pp. 1538, 2023, ISSN: 1044-0305, 1879-1123.
Abstract | Links | BibTeX | Altmetric | Tags: experimental design, LBTD, photofragmentation
@article{dauletyarovVaporizationIntactNeutral2023,
title = {Vaporization of Intact Neutral Biomolecules Using Laser-Based Thermal Desorption},
author = {Yerbolat Dauletyarov and Siwen Wang and Daniel A. Horke},
url = {https://pubs.acs.org/doi/10.1021/jasms.3c00194},
doi = {10.1021/jasms.3c00194},
issn = {1044-0305, 1879-1123},
year = {2023},
date = {2023-06-01},
urldate = {2023-06-01},
journal = {J. Am. Soc. Mass Spectrom.},
volume = {34},
pages = {1538},
abstract = {The production of a clean neutral molecular sample is a crucial step in many gas-phase spectroscopy and reaction dynamics experiments investigating neutral species. Unfortunately, conventional methods based on heating cannot be used with most nonvolatile biomolecules due to their thermal instability. In this paper, we demonstrate the application of laser-based thermal desorption (LBTD) to produce neutral molecular plumes of biomolecules such as dipeptides and lipids. Specifically, we report mass spectra of glycylglycine, glycyl-L-alanine, and cholesterol obtained using LBTD vaporization, followed by soft femtosecond multiphoton ionization (fs-MPI) at 400 nm. For all molecules, the signal from the intact precursor ion was observed, highlighting the softness and applicability of the LBTD and fs-MPI approach. In more detail, cholesterol underwent hardly any fragmentation. Both dipeptides fragmented significantly, although mostly through only a single channel, which we attribute to the fs-MPI process.},
keywords = {experimental design, LBTD, photofragmentation},
pubstate = {published},
tppubtype = {article}
}
The production of a clean neutral molecular sample is a crucial step in many gas-phase spectroscopy and reaction dynamics experiments investigating neutral species. Unfortunately, conventional methods based on heating cannot be used with most nonvolatile biomolecules due to their thermal instability. In this paper, we demonstrate the application of laser-based thermal desorption (LBTD) to produce neutral molecular plumes of biomolecules such as dipeptides and lipids. Specifically, we report mass spectra of glycylglycine, glycyl-L-alanine, and cholesterol obtained using LBTD vaporization, followed by soft femtosecond multiphoton ionization (fs-MPI) at 400 nm. For all molecules, the signal from the intact precursor ion was observed, highlighting the softness and applicability of the LBTD and fs-MPI approach. In more detail, cholesterol underwent hardly any fragmentation. Both dipeptides fragmented significantly, although mostly through only a single channel, which we attribute to the fs-MPI process.
2.
Wang S, Dauletyarov Y, Krüger P, Horke D A
High-throughput UV-photofragmentation studies of thymine and guanine Journal Article
In: Phys. Chem. Chem. Phys., vol. 25, pp. 12322, 2023.
Abstract | Links | BibTeX | Altmetric | Tags: experimental design, LBTD, photofragmentation
@article{D3CP00328K,
title = {High-throughput UV-photofragmentation studies of thymine and guanine},
author = {Siwen Wang and Yerbolat Dauletyarov and Peter Kr\"{u}ger and Daniel A. Horke},
url = {http://dx.doi.org/10.1039/D3CP00328K},
doi = {10.1039/D3CP00328K},
year = {2023},
date = {2023-04-15},
urldate = {2023-01-01},
journal = {Phys. Chem. Chem. Phys.},
volume = {25},
pages = {12322},
publisher = {The Royal Society of Chemistry},
abstract = {High-throughput photofragmentation studies of thymine and guanine were performed at 257 and 343 nm and for a wide range of ionisation laser intensities. Combining a continuous laser-based thermal desorption source with femtosecond multiphoton ionisation using a 50 kHz repetition rate laser allowed us to produce detailed 2D maps of fragmentation as a function of incident laser intensity. The fragmentation was distinctly soft, the parent ions being at least an order of magnitude more abundant than fragment ions. For thymine there was a single dominant fragmentation channel, which involves consecutive HNCO and CO losses. In contrast, for guanine there were several competing ones, the most probable channel corresponding to CH2N2 loss through opening of the pyrimidine ring. The dependence of parent ion abundance on the ionisation laser intensity showed that at 257 nm the ionisation of thymine is a 1 + 1 resonance enhanced process through its open-shell singlet state.},
keywords = {experimental design, LBTD, photofragmentation},
pubstate = {published},
tppubtype = {article}
}
High-throughput photofragmentation studies of thymine and guanine were performed at 257 and 343 nm and for a wide range of ionisation laser intensities. Combining a continuous laser-based thermal desorption source with femtosecond multiphoton ionisation using a 50 kHz repetition rate laser allowed us to produce detailed 2D maps of fragmentation as a function of incident laser intensity. The fragmentation was distinctly soft, the parent ions being at least an order of magnitude more abundant than fragment ions. For thymine there was a single dominant fragmentation channel, which involves consecutive HNCO and CO losses. In contrast, for guanine there were several competing ones, the most probable channel corresponding to CH2N2 loss through opening of the pyrimidine ring. The dependence of parent ion abundance on the ionisation laser intensity showed that at 257 nm the ionisation of thymine is a 1 + 1 resonance enhanced process through its open-shell singlet state.
2022
1.
Wang S, Abma G L, Krüger P, Roij A, Balster M, Janssen N, Horke D A
Comparing Pulsed and Continuous Laser-Induced Acoustic Desorption (LIAD) as Sources for Intact Biomolecules Journal Article
In: Eur. Phys. J. D, vol. 76, no. 7, pp. 128, 2022, ISSN: 1434-6060, 1434-6079.
Abstract | Links | BibTeX | Altmetric | Tags: experimental design, LBTD, photofragmentation
@article{wangComparingPulsedContinuous2022,
title = {Comparing Pulsed and Continuous Laser-Induced Acoustic Desorption (LIAD) as Sources for Intact Biomolecules},
author = {Siwen Wang and Grite L. Abma and Peter Kr\"{u}ger and Andre Roij and Michiel Balster and Niek Janssen and Daniel A. Horke},
url = {https://link.springer.com/10.1140/epjd/s10053-022-00459-7},
doi = {10.1140/epjd/s10053-022-00459-7},
issn = {1434-6060, 1434-6079},
year = {2022},
date = {2022-07-01},
urldate = {2022-07-01},
journal = {Eur. Phys. J. D},
volume = {76},
number = {7},
pages = {128},
abstract = {A major obstacle to the gas-phase study of larger (bio)molecular systems is the vaporisation step, that is, the introduction of intact sample molecules into the gas-phase. A promising approach is the use of laser-induced acoustic desorption (LIAD) sources, which have been demonstrated using both nanosecond pulsed and continuous desorption lasers. We directly compare here both approaches for the first time under otherwise identical conditions using adenine as a prototypical biological molecule, and study the produced molecular plumes using femtosecond multiphoton ionisation. We observe different desorption mechanisms at play for the two different desorption laser sources; however, we find no evidence in either case that the desorption process leads to fragmentation of the target molecule unless excessive desorption energy is applied. This makes LIAD a powerful approach for techniques that require high density and high purity samples in the gas-phase, such as ultrafast dynamics studies or diffraction experiments.},
keywords = {experimental design, LBTD, photofragmentation},
pubstate = {published},
tppubtype = {article}
}
A major obstacle to the gas-phase study of larger (bio)molecular systems is the vaporisation step, that is, the introduction of intact sample molecules into the gas-phase. A promising approach is the use of laser-induced acoustic desorption (LIAD) sources, which have been demonstrated using both nanosecond pulsed and continuous desorption lasers. We directly compare here both approaches for the first time under otherwise identical conditions using adenine as a prototypical biological molecule, and study the produced molecular plumes using femtosecond multiphoton ionisation. We observe different desorption mechanisms at play for the two different desorption laser sources; however, we find no evidence in either case that the desorption process leads to fragmentation of the target molecule unless excessive desorption energy is applied. This makes LIAD a powerful approach for techniques that require high density and high purity samples in the gas-phase, such as ultrafast dynamics studies or diffraction experiments.