Li can find itself a wide range of applications since it is the lightest metal. However, Li detection by microscopy-based techniques is problematic because of the highly susceptible nature during electron beam irradiation. ToF-SIMS is a versatile technique to detect Li but the detection of light materials is also problematic due to the large ion contaminated zone and low sputtering yield. By combining ToF-SIMS with a recently launched Xe ion source FIB-SEM, which has small ion contamination and high sputtering yield features, can produce more realistic data at near surface and below the surface region especially for the detection of lightweight materials such as Li. In this study, Li detection and mapping capabilities of ToF-SIMS attached to the FIB-SEM with Ga and Xe ion sources were discussed for Al incorporated Li7 La3 Zr2 O12 solid electrolyte sample that contains Li and Al rich regions at triple junctions. In spite of smoother milling from Ga source, Xe performs more precisely in Li mapping. Low ion contaminated zone, high sputtering yield and low straggling obtained from Monte Carlo simulations are the main advantages of Xe ion sources. The Li detection efficiency for Xe is higher than Ga source discriminating the LiAlO2 phase placed at the triple junctions of grains and La2 Zr2 O7 regions placed at the outer side of LLZO neighbouring the LiAlO2 phase. LAY DESCRIPTION: Li can find itself a wide range of applications since it is the lightest metal. However, Li detection by microscopy-based techniques is problematic because of the highly susceptible nature during electron beam irradiation. ToF-SIMS is a versatile technique to detect Li but the detection of light materials is also problematic due to the large ion contaminated zone and low sputtering yield. By combining ToF-SIMS with a recently launched Xe ion source FIB-SEM, which has small ion contamination and high sputtering yield features, can produce more realistic data at near surface and below the surface region especially for the detection of lightweight materials such as Li. In this study, Li detection and mapping capabilities of ToF-SIMS attached to the FIB-SEM with Ga and Xe ion sources were discussed for Al incorporated Li7 La3 Zr2 O12 solid electrolyte sample that contains Li and Al rich regions at triple junctions. In spite of smoother milling from Ga source, Xe performs more precisely in Li mapping. Results were also supported from Monte Carlo simulations of ion-atom interactions. The Li detection resolution of xenon is much higher than gallium source discriminating the LiAlO2 phase placed at the triple junctions of grains and La2 Zr2 O7 regions placed at the outer side of LLZO neighbouring the LiAlO2 phase.

• Klíčová slova
• FIB-SEM, Ga ion source, Li detection, ToF-SIMS, Xe ion source,
• Publikační typ
• časopisecké články MeSH

We describe the optimization and application of an ion-atomic beam source for ion-beam-assisted deposition of ultrathin films in ultrahigh vacuum. The device combines an effusion cell and electron-impact ion beam source to produce ultra-low energy (20-200 eV) ion beams and thermal atomic beams simultaneously. The source was equipped with a focusing system of electrostatic electrodes increasing the maximum nitrogen ion current density in the beam of a diameter of ≈15 mm by one order of magnitude (j ≈ 1000 nA/cm(2)). Hence, a successful growth of GaN ultrathin films on Si(111) 7 × 7 substrate surfaces at reasonable times and temperatures significantly lower (RT, 300 °C) than in conventional metalorganic chemical vapor deposition technologies (≈1000 °C) was achieved. The chemical composition of these films was characterized in situ by X-ray Photoelectron Spectroscopy and morphology ex situ using Scanning Electron Microscopy. It has been shown that the morphology of GaN layers strongly depends on the relative Ga-N bond concentration in the layers.

• Publikační typ
• časopisecké články MeSH

For low emission currents from around 1 microA Ga liquid-metal ion sources (LMIS) produce fine optically bright ion beams that are strongly limited by the Coulomb particle-particle interactions. We present computations of the energy spread, the beam virtual crossover size, and beam brightness based on direct numerical integration of the equation of motion in a numerically calculated field for a number of dimensions of the emission tip. The Coulomb particle-particle interactions are included into the calculation of ion beam evolution. A comparison with experimental data allows to estimate the tip size.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Dielectric barrier discharge ionization (DBDI) sources, employing low-temperature plasma, have emerged as sensitive and efficient ionization tools with various atmospheric pressure ionization processes. In this review, we summarize a historical overview of the development of DBDI, highlighting key principles of gas-phase ion chemistry and the mechanisms underlying the ionization processes within the DBDI source. These processes start with the formation of reagent ions or metastable atoms from the discharge gas, which depends on the nature of the gas (helium, nitrogen, air) and on the presence of water vapor or other compounds or dopants. The processes of ionizing the analyte molecules are summarized, including Penning ionization, electron transfer, proton transfer and ligand switching from secondary hydrated hydronium ions. Presently, the DBDI-MS methods face a challenge in the accurate quantification of gaseous analytes, limiting its broader application in biological, environmental, and medical realms where relative quantification using standards is inherently complex for gaseous matrices. Finally, we propose future avenues of research to enhance the analytical capabilities of DBDI-MS.

• Klíčová slova
• dielectric barrier discharge ionization, direct analyses, gas phase, ion chemistry,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

RATIONALE: In soft chemical ionization mass spectrometry, analyte ions are produced via ion-molecule reactions in the reactor. When an electric field E is imposed, the ion drift velocity vd determines the reaction time and the effective ion temperature. Agreement between experimental ion mobilities and theoretical predictions confirms the accuracy of the ion residence time measurement procedure. METHODS: A selected ion flow-drift tube (SIFDT), an instrument with a chemical ionization source, was used to produce protonated aldehydes and selectively inject them into the resistive glass drift tube filled with He. Arrival-time distributions of ions were obtained using the Hadamard modulation. Reduced ion mobilities were then obtained at a pressure of 2 hPa in the E/N range of 5-15 Td. Theoretical ion mobility values were calculated using two methods: hard-sphere approximation and trajectory modelling. RESULTS: The measured mobilities of three saturated and three unsaturated protonated aldehydes do not show substantial variation across the studied E/N range. Effective temperatures calculated using the Wannier formula from measured gas temperatures ranged from 300 to 315 K. Experimentally obtained values of the near-zero- E/N-reduced ion mobilities agree with both methods of calculations typically within ±3% standard deviation (maximum ±5%). CONCLUSIONS: The experimental SIFDT values of reduced mobilities in He of protonated aldehyde molecules generated from a chemical ionization source are in close agreement with two different theoretical methods based on the density functional theory calculations of ion geometries and partial atomic charges. Besides its fundamental importance, the ion mobility results validate the correct operation of the drift tube reactor and the ion residence time measurement procedure. Diffusion losses can also be determined from these results.

• Publikační typ
• časopisecké články MeSH

Soft chemical ionization mass spectrometry techniques, particularly the well-established proton transfer reaction mass spectrometry, PTR-MS, and selected ion flow tube mass spectrometry, SIFT-MS, are widely used for real-time quantification of volatile organic compounds in ambient air and exhaled breath with applications ranging from environmental science to medicine. The most common reagent ions H3O+, NO+, or O2+• can be selected either by quadrupole mass filtering from a discharge ion source, which is relatively inefficient, or by switching the gas/vapor in the ion source, which is relatively slow. The chosen reagent ions are introduced into a flow tube or flow-drift tube reactor where they react with analyte molecules in sample gas. This article describes a new electrostatic reagent ion switching, ERIS, technique by which H3O+, NO+, and O2+• reagent ions, produced simultaneously in three separate gas discharges, can be purified in post-discharge source drift tubes, switched rapidly, and selected for transport into a flow-drift tube reactor. The construction of the device and the ion-molecule chemistry exploited to purify the individual reagent ions are described. The speed and sensitivity of ERIS coupled to a selected ion flow-drift tube mass spectrometry, SIFDT-MS, is demonstrated by the simultaneous quantification of methanol with H3O+, acetone with NO+, and dimethyl sulfide with O2+• reagent ions in single breath exhalations. The present ERIS approach is shown to be preferable to the previously used quadrupole filtering, as it increases analytical sensitivity of the SIFDT-MS instrument while reducing its size and the required number of vacuum pumps.

• MeSH
• dechové testy * MeSH
• hmotnostní spektrometrie přístrojové vybavení   MeSH
• indikátory a reagencie analýza   MeSH
• ionty analýza   MeSH
• kyslík analýza   MeSH
• lidé MeSH
• oniové sloučeniny analýza   MeSH
• oxid dusnatý analýza   MeSH
• plyny chemie   MeSH
• statická elektřina MeSH
• tělesné tekutiny chemie   MeSH
• vzduch MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hydronium ion MeSH Prohlížeč
• indikátory a reagencie MeSH
• ionty MeSH
• kyslík MeSH
• oniové sloučeniny MeSH
• oxid dusnatý MeSH
• plyny MeSH

This study demonstrates the use of nanoparticles prepared by a gas aggregation source for fabricating structures by combining laser sintering and ablation. At first, the morphology and optical properties of prepared nanoparticle coatings were characterized. Then, the response of coatings to laser irradiation at different powers or exposure times was studied by in situ time-of-flight mass spectrometry, followed by scanning electron microscopy measurements of the resulting structures. By comparing the numbers of detected Ag ions, that were ablated and desorbed, with changes in morphology after irradiation, the optimum conditions for laser sintering and ablation of Ag nanoparticle coatings were found. As a proof of concept we fabricated micromirrors from sintered metal, microwires from both sintered metal and interconnected nanoparticles, and arbitrary metallic bulky or nanoparticle patterns. Vacuum compatibility and the possibility of fabrication of both metallic and nanoparticle structures in one step predetermines applications of developed method in electronics or sensing.

• Klíčová slova
• additive manufacturing, gas aggregation, laser sintering, metal printing, nanoparticles,
• Publikační typ
• časopisecké články MeSH

Prismatic lithium-ion batteries (LIBs) are considered promising electric energy sources in electromobility applications due to their efficient space utilization. However, their sensitivity to external and internal influences and reduced durability lead to inflation risk and potential explosions throughout their lifecycle. These critical processes are strongly influenced by the inner construction of the cell, especially concerning the coating and mechanical fixation. This study subjects a commercially available prismatic LIB cell to comprehensive, correlative analysis employing various imaging techniques. The inner structure of the entire cell is visualized non-destructively by X-ray computed tomography (CT), enabling the identification of critical design flaws prior to electrochemical cycling. Electrochemical cycling simulates the battery lifecycle, and the cell is subsequently disassembled in the fully charged state. The usage of the inert-gas transfer system allowed the preparation of Broad Ion Beam (BIB) electrodes cross-sections in a fully native state and for the first time to observe the tearing of graphite particles due to over-lithiation. Established region labeling system allowed to use CT and scanning electron microscopy (SEM) correlatively to identify critical regions. After 100 cycles, a 40% capacity loss was observed and event diagram describing deagradation mechanisms, related both to the cell design and to the processes occurring at high load, was created.

• Klíčová slova
• Lithium plating, Lithium-ion battery, Prismatic cell, SEM, X-ray computed tomography,
• Publikační typ
• časopisecké články MeSH

Untargeted mass spectrometry (MS) experiments produce complex, multidimensional data that are practically impossible to investigate manually. For this reason, computational pipelines are needed to extract relevant information from raw spectral data and convert it into a more comprehensible format. Depending on the sample type and/or goal of the study, a variety of MS platforms can be used for such analysis. MZmine is an open-source software for the processing of raw spectral data generated by different MS platforms. Examples include liquid chromatography-MS, gas chromatography-MS and MS-imaging. These data might typically be associated with various applications including metabolomics and lipidomics. Moreover, the third version of the software, described herein, supports the processing of ion mobility spectrometry (IMS) data. The present protocol provides three distinct procedures to perform feature detection and annotation of untargeted MS data produced by different instrumental setups: liquid chromatography-(IMS-)MS, gas chromatography-MS and (IMS-)MS imaging. For training purposes, example datasets are provided together with configuration batch files (i.e., list of processing steps and parameters) to allow new users to easily replicate the described workflows. Depending on the number of data files and available computing resources, we anticipate this to take between 2 and 24 h for new MZmine users and nonexperts. Within each procedure, we provide a detailed description for all processing parameters together with instructions/recommendations for their optimization. The main generated outputs are represented by aligned feature tables and fragmentation spectra lists that can be used by other third-party tools for further downstream analysis.

• MeSH
• chromatografie kapalinová metody   MeSH
• hmotnostní spektrometrie * metody   MeSH
• iontová mobilní spektrometrie metody   MeSH
• metabolomika metody   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• reprodukovatelnost výsledků MeSH
• software * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

RATIONALE: Secondary electrospray ionization (SESI) in a water spray environment at atmospheric pressure involves the reactions of hydrated hydronium reagent ions, H3 O+ (H2 O)n , with trace analyte compounds in air samples. Understanding the formation and dehydration of reagent and analyte ions is the foundation for meaningful quantification of trace compounds by SESI-mass spectrometry (MS). METHODS: A numerical model based on gas-phase ion thermochemistry is developed that describes equilibria in H3 O+ (H2 O)n reagent cluster ion distributions and ligand switching reactions with polar NH3 molecules leading to equilibrated hydrated ammonium ions NH4 + (H2 O)m . The model predictions are compared with experimental results obtained using a cylindrical SESI source coupled to an ion-trap mass spectrometer via a heated ion transfer capillary. Non-polar isoprene, C5 H8 , was used to further probe the nature of the reagent ions. RESULTS: Equilibrium distributions of H3 O+ (H2 O)n ions and their reactions with NH3 molecules have been characterized by the model in the near-atmospheric pressure SESI source. NH3 analyte molecules displace H2 O ligands from the H3 O+ (H2 O)n ions at the collisional rate forming NH4 + (H2 O)m ions, which travel through the heated ion transfer capillary losing H2 O molecules. The data for variable NH3 concentrations match the model predictions and the C5 H8 test substantiates the notion of dehydration in the heated capillary. CONCLUSIONS: Large cluster ions formed in the SESI region are dehydrated to H3 O+ (H2 O)1,2,3 and NH4 + (H2 O)1,2 while passing through the heated capillary, and considerable diffusion losses also occur. This phenomenon is also predicted for other polar analyte molecules, A, that can undergo similar switching reactions, thus forming AH+ and AH+ (H2 O)m analyte ions.

• Publikační typ
• časopisecké články MeSH