@article{ROTH2024168820,

title = {New aerodynamic lens injector for single particle diffractive imaging},

author = {Nils Roth and Daniel A. Horke and Jannik L\"{u}bke and Amit K. Samanta and Armando D. Estillore and Lena Worbs and Nicolai Pohlman and Kartik Ayyer and Andrew Morgan and Holger Fleckenstein and Martin Domaracky and Benjamin Erk and Christopher Passow and Jonathan Correa and Oleksandr Yefanov and Anton Barty and Sa\v{s}a Bajt and Richard A. Kirian and Henry N. Chapman and Jochen K\"{u}pper},

url = {https://www.sciencedirect.com/science/article/pii/S0168900223008112},

doi = {https://doi.org/10.1016/j.nima.2023.168820},

issn = {0168-9002},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},

volume = {1058},

pages = {168820},

abstract = {An aerodynamic lens injector was developed specifically for the needs of single-particle diffractive imaging experiments at free-electron lasers. Its design allows for quick changes of injector geometries and focusing properties in order to optimize injection for specific individual samples. Here, we present results of its first use at the FLASH free-electron-laser facility. Recorded diffraction patterns of polystyrene spheres are modeled using Mie scattering, which allowed for the characterization of the particle beam under diffractive-imaging conditions and yielded good agreement with particle-trajectory simulations. The complex refractive index of polystyrene at λ=4.5nm was determined as m=0.976−0.001i.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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 = {},

pubstate = {published},

tppubtype = {article}

}

@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 = {},

pubstate = {published},

tppubtype = {article}

}