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Direct inlet probe atmospheric pressure photo and chemical ionization coupled to ultra-high resolution mass spectrometry for the description of lignocellulosic biomass
摘要： Lignocellulosic biomass, in particular wood, is a complex mixture containing cellulose, hemicellulose, lignin, and other trace compounds. Chemical analysis of these biomasses, especially lignin components, is a challenge. Lignin is a highly reticulated polymer that is poorly soluble and usually requires chemical, enzymatic, or thermal degradation for its analysis. Here, we studied the thermal degradation of lignocellulosic biomass using a direct insertion probe (DIP). DIP was used with two ionization sources: atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) coupled to ultra-high-resolution mass spectrometry. Beech lignocellulosic biomass sample were used to develop the DIP-APCI/APPI methodology. Two other wood species (maple and oak) were analyzed after optimization of DIP parameters. The two ionization sources were compared at first and showed different response towards beech sample, according to the source specificity. APPI was more specific to lignin degradation compounds, whereas APCI covered a larger variety of oxygenated compounds, e.g., fatty acids, polyphenolics compounds, in addition to lignin degradation products. The study of the thermo-desorption profile gave information on the different steps of lignocellulosic biomass pyrolysis. The comparison of the three feed sample types (oak, maple, and beech), using principal component analysis (PCA) with DIP-APCI experiments, showed molecular level differences between beech wood pellets and the two others wood species (maple and oak).
关键词： high-resolution mass spectrometry,APPI,APCI,direct inlet probe,biomass
更新于2025-09-19 17:13:59
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Quantitative spatially resolved <i>post-mortem</i> analysis of lithium distribution and transition metal depositions on cycled electrodes <i>via</i> a laser ablation-inductively coupled plasma-optical emission spectrometry method
摘要： Diminishing the loss of performance of lithium ion batteries (LIBs) is a challenge that is yet to be ful?lled. Understanding of deterioration processes and mechanisms (i.e., so-called aging) requires analytically accurate examination of aged cells. Changes in the distribution of lithium or transition metals in the LIB cells can in?uence their cycle and calendar life signi?cantly. As electrochemically treated cells and especially their electrodes do not age homogeneously and the local electrochemistry (e.g. deposition patterns) is strongly dependent on surface properties, bulk analysis is not a satisfactory investigation method. Therefore, a surface sensitive method, namely laser ablation-inductively coupled plasma-optical emission spectrometry (LA-ICP-OES) is presented. LIB cells with lithium metal oxide LiNi1/3Co1/3Mn1/3O2 (NCM111) as cathode material and graphite as anode material are investigated using a 213 nm Nd:YAG laser.
关键词： graphite,aging,laser ablation-inductively coupled plasma-optical emission spectrometry,NCM111,LA-ICP-OES,LIBs,Nd:YAG laser,lithium ion batteries
更新于2025-09-19 17:13:59
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Development and validation of an analytical methodology for the determination of ?′2H and ?′18O in formation water based on Laser-Based infrared absorption spectroscopy
摘要： The present work describes the application of the Eurachem validation method to the determination of δ2H and δ18O in high-salinity petroleum using near-infrared laser spectrometry from Los Gatos Research (laser water isotopic analyzer). The validation protocol involved selectivity, linearity, trueness, precision and ruggedness. Although the method is not selective for methanol and ethanol, it was selective for formic acid and acetic acid, which are additives applied by the petroleum industry. The linearity for δ2H in the range of -2.74‰ to -427.5‰ and for δ18O from -0.98‰ to -55.5‰, with a determination coefficient of 1.00, has been reached. Trueness was verified by the participation in an interlaboratory exercise promoted by the International Atomic Energy Agency (IAEA) and by paired formation water sample analysis applying laser spectrometry and isotopic ratio mass spectrometry (IRMS). The achieved precision fits with the equipment specification, and both repeatability and intermediary precision were equal to 0.50 ‰ and 0.10 ‰ for δ2H and δ18O, respectively. An effect of salinity and MgCl2 up to 250 g L-1 and 50 g L-1, respectively, was not observed. The developed protocol was applied to ten petroleum water samples with salinity in the range of 28-217 g L-1. One of the samples fit the global meteoric water line (GMWL), and the others were found below the GMWL.
关键词： formation water,Oil exploration,laser spectrometry,isotopic analysis
更新于2025-09-19 17:13:59
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Mass spectrometry imaging of thin-layer chromatography plates using laser desorption/low-temperature plasma ionisation
摘要： Thin-layer chromatography (TLC) is a classic method for the separation and analysis of complex mixtures. Biological assays, chemical derivatisation and spectroscopy techniques are compatible with TLC and provide extra information about isolated compounds. However, coupling TLC to mass spectrometry is hampered by the difficulty to desorb the analytes from the silica surfaces. In this study, we used a multimodal ion source for laser desorption (LD) and low-temperature plasma (LTP) post-ionisation. Efficient desorption was reached by covering the TLC plates with activated carbon. Regions of interest can be analysed by spots, by lines or by area. We show the separation of methylxanthines from coffee, tea and cocoa preparations by TLC, with subsequent mass spectrometry imaging (MSI). Using a lateral resolution of 400 mm × 400 mm, allowed the acquisition of 21,895 spectra in 2.4 h (2.5 pixels/s). Further, we demonstrate the possibility of direct mass fragmentation studies and quantification. We mounted the system on an Open LabBot with a theoretical lateral resolution of 12.5 mm and performed the visualisation of ions of interest and the pixel-wise review of mass spectra with our free software RmsiGUI (https://bitbucket.org/lababi/rmsigui). This non-proprietary and modular platform enables the cost-efficient adaption of the system and further development by the community.
关键词： mass spectrometry imaging,thin-layer chromatography,low-temperature plasma,laser desorption,ambient ionisation
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - Bangkok, Thailand (2019.6.12-2019.6.14)] 2019 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - Development of Automated LED Light Compensation System for Lycopersicon Esculentum
摘要： The cells in an organism emit different amounts of proteins according to their clinical state (healthy/pathological, for instance). The resulting proteomic pro?le can be used for early detection, diagnosis, and therapy planning. In this paper, we study the classi?cation of a proteomic sample from the point of view of an inverse problem with a joint Bayesian solution, called inversion-classi?cation. We propose a hierarchical physical forward model and present encouraging results from both simulation and clinical data.
关键词： proteins,classi?cation algorithms,proteomics,Statistical signal processing,probability,liquid chromatography,mass spectrometry,selective reaction monitoring,inverse problems,mathematical modelling
更新于2025-09-19 17:13:59
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The Smallest Aromatic Tetracation Produced in Gas Phase by Intense Femtosecond Laser Pulses
摘要： We report the production of long-lived tetracation, which is the smallest aromatic tetracation hexafluorobenzene ever investigated, by 0.8 μm femtosecond laser pulses. The tetracation yield relative to that of trication radical is 0.11. Using the time-of-flight mass spectrometer equipped with the fast ion gate and the curved field reflectron, we estimate the lower limit of the lifetime of tetracation to be 9 μs. Confinement of multiple positive charges in a small organic molecule is unexpected; however, our finding is an answer of this fundamental concern.
关键词： multiply charged ion,tunnel ionization,time-of-flight mass spectrometry
更新于2025-09-19 17:13:59
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Quantifying and improving the optical performance of the Laser Ablation Aerosol Particle Time of Flight Mass Spectrometer (LAAPToF) instrument
摘要： Single particle mass spectrometer (SPMS) instruments have been used for in-situ chemical characterization of atmospheric aerosols, both in the field and laboratory, for over two decades. SPMSs typically combine precise optical particle sizing with laser desorption and ionization followed by time of flight mass spectrometry. Among the advantages of SPMSs over other aerosol chemistry measurement techniques are their single particle resolution and high sensitivity counting efficiency in the size range 500-2000 nm vacuum aerodynamic diameter. We also present mass spectral performance for characterizing atmospherically-relevant particles in a comparison to a current SPMS design, the Particle Analysis by Laser Mass Spectrometry. The AeroMegt Laser Ablation Aerosol Particle Time of Flight Mass Spectrometer (LAAPToF) is a commercially available member of this instrument class, aiming for a compact size and simplicity for the end user. This paper quantifies the performance of LAAPToF with an emphasis on optical counting efficiency. Recommendations for improving detection compared to the base LAAPToF hardware are described. Our results show that changes to the optical detection scheme can lead to over two orders of magnitude improvement in optical counting efficiency.
关键词： aerosol chemistry,LAAPToF,Single particle mass spectrometer,optical counting efficiency,time of flight mass spectrometry
更新于2025-09-19 17:13:59
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Nanocytotoxicity using matrix-assisted laser desorption ionization mass spectrometry
摘要： The analysis of bacteria species using MALDI-MS is simple and fast compared with traditional analysis methods such as cell culture, which requires days and sometime weeks.
关键词： nanocytotoxicity,matrix-assisted laser desorption ionization mass spectrometry,nanomedicine,antibacterials
更新于2025-09-19 17:13:59
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Silicon‐Based Laser Desorption Ionization Mass Spectrometry for the Analysis of Biomolecules: A Progress Report
摘要： Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used in the biomedical field for the label-free analysis of molecules such as drugs, lipids, peptides, proteins, and biological tissues for molecular imaging. However, organic matrices used in traditional MALDI-MS applications introduce excessive interferences in the low m/z range. For this reason, nanostructured materials—and in particular silicon-based LDI strategies—have become a promising alternative, since they provide a much weaker background. Herein, the recent developments in fabrication, functionalization, and practical applications of silicon-based LDI-MS methods are reviewed. Also the basic requirements of silicon-based substrates for optimal LDI analysis by providing an overview of the LDI mechanisms that use silicon-based substrates instead of organic matrices are reported. Finally, the considerable potential of silicon-based substrates is discussed, giving suggestions for topics for future research.
关键词： silicon nanostructures,laser desorption ionization (LDI),surface functionalization,mass spectrometry imaging (MSI)
更新于2025-09-19 17:13:59
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Dual Laser and Desorption Electrospray Ionization Mass Spectrometry Imaging Using the Same Interface
摘要： For a more comprehensive characterization of molecular heterogeneities of matter, multi-modal mass spectrometry imaging must be developed to take advantage of the complementarity of information available through different ionization mechanisms. We report the design, implementation, and performance validation of a laser desorption imaging interface comprised of add-on components that adapt a commercial Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) imaging interface for dual imaging of Picosecond Infrared Laser Mass Spectrometry (PIRL-MS) with DESI-MS. The interface utilizes hardware elements and data analysis pipelines already established for DESI-MS imaging, and was further validated in cancer margin assessments using human medulloblastoma cancers. The PIRL-MS images were robust and reproducible across multiple experimental runs on independently prepared xenograft tumours, and could be segmented into cancer and healthy regions in concordance with pathology using a variety of supervised and unsupervised clustering methods. The spectral quality and complexity obtained with this interface were examined with infiltrating and non-infiltrating tumours, and were comparable to other mass spectrometry analysis interfaces. The average PIRL-MS spectra from spatially resolved images could be used for robust cancer m/z model building to classify medulloblastoma cancer from healthy tissue without any misclassifications, an observation that held true over close to 70 sampling data points. While the unsupervised spectral analysis methods suggested a slight suppression of signal in the phospholipid range compared to the hand-held configuration, these changes were insufficient to hamper utility in cancer margin assessment with spatially resolved data obtained with our interface. Dual PIRL-MS and DESI-MS imaging of consecutive sections, as suggested by multivariate loading plots, revealed highly complementary molecular information with m/z values identifiable with one desorption method sufficient to reveal cancer regions being absent in another, further emphasising the need for effective hardware and software interfaces for dual mass spectrometry imaging.
关键词： mass spectrometry imaging,laser desorption,DESI-MS,PIRL-MS,medulloblastoma,cancer margin assessment
更新于2025-09-19 17:13:59