Gas-phase Separation Research Articles

Oriented MFI films for gas phase separation, catalysis, and sensing: A review of crystal growth, design, and function enabling

Oriented MFI films for gas phase separation, catalysis, and sensing: A review of crystal growth, design, and function enabling

Oxide unlocking electron beam melting to separate boron for impurities co-removal of metallurgical grade silicon

Removing stubborn B from Si efficiently and simplifying the purification process are critical challenges that must be addressed in the manufacture of solar grade silicon (SoG-Si) via metallurgical routes. Herein, B is flexibly coupled with other impurities separation procedure, so that metallurgical grade silicon (MG-Si) is purified through simplified electron beam melting (EBM) unlocked by a few oxides (0.1 wt%). EBM fulfills three functions including promotion of oxidation, evaporation of impurities, and induction of directional solidification, giving high-temperature field, high vacuum field, and intense melt convection, which not only ensures the smooth process of B oxidation but also favors the co-removal of other impurities, obtaining high purity Si. As a result, purified Si ingot exhibits a low content of B (from 12.76 ppmw to 2.92 ppmw), and the total content of major impurities is reduced from 1217.24 ppmw to 5.66 ppmw. Significantly, pure SiO2 could more readily access the high-temperature region of Si melt during EBM, offering distinct advantages for the oxidation gas phase separation of B. This work provides an efficient and robust method for expanding ideas of B removal and simplifying metallurgical routes.

Separation and Simultaneous Trapping of Multiply Charged and Singly Charged Ions for Mass Spectrometry: Application to Lipid Mixtures.

Conventional electrospray ionization (ESI) of mixtures can give rise to singly and multiply charged analyte species that overlap in mass-to-charge (m/z) ratios, which can complicate the analysis of individual components. The overlap in m/z for ions of different mass and charge is particularly problematic when ions of low relative abundance are of interest. For example, cardiolipins (CLs) are structurally complex phospholipids present in low relative abundance in the lipidome but play crucial roles in mitochondrial metabolism and various regulatory processes. ESI of CLs in negative ion mode shows abundant doubly deprotonated ions and minor singly deprotonated ions. In the ESI of lipid extracts, highly abundant singly charged phospholipids extensively overlap in m/z space with CL dianions of much lesser abundance, thereby complicating the study of the CLs. To address this challenge, we employed a gas-phase approach to separate singly charged ions from a population of ions of mixed charge states while allowing for the storage of one or both of the separated ion populations. Herein, we describe the considerations for applying enhanced singly charged (ESC) and enhanced multiply charged (EMC) scans to perform a gas-phase separation of singly charged lipids from doubly charged lipids in an Escherichia coli extract. This method allows for improved signal-to-noise (S/N) ratio of low abundance ions with minimal overall signal loss, removal of "chemical noise" arising from singly charged ions, and allows for retention of spatially separated ions within a mass spectrometer.

Molecular and Structural Characterization of Isomeric Compounds in Atmospheric Organic Aerosol Using Ion Mobility-Mass Spectrometry.

Secondary organic aerosol (SOA) formed through multiphase atmospheric chemistry makes up a large fraction of airborne particles. The chemical composition and molecular structures of SOA constituents vary between different emission sources and aging processes in the atmosphere, which complicates their identification. In this work, we employ drift tube ion mobility spectrometry with quadrupole time-of-flight mass spectrometry (IM-MS) detection for rapid gas-phase separation and multidimensional characterization of isomers in two biogenic SOAs produced from ozonolysis of isomeric monoterpenes, d-limonene (LSOA) and α-pinene (PSOA). SOA samples were ionized using electrospray ionization (ESI) and characterized using IM-MS in both positive and negative ionization modes. The IM-derived collision cross sections in nitrogen gas (DTCCSN2 ) for individual SOA components were obtained using multifield and single-field measurements. A novel application of IM multiplexing/high-resolution demultiplexing methodology was employed to increase sensitivity, improve peak shapes, and augment mobility baseline resolution, which revealed several isomeric structures for the measured ions. For LSOA and PSOA samples, we report significant structural differences of the isomer structures. Molecular structural calculations using density functional theory combined with the theoretical modeling of CCS values provide insights into the structural differences between LSOA and PSOA constituents. The average DTCCSN2 values for monomeric SOA components observed as [M + Na]+ ions are 3-6% higher than those of their [M - H]- counterparts. Meanwhile, dimeric and trimeric isomer components in both samples showed an inverse trend with the relevant values of [M - H]- ions being 3-7% higher than their [M + Na]+ counterparts, respectively. The results indicate that the structures of Na+-coordinated oligomeric ions are more compact than those of the corresponding deprotonated species. The coordination with Na+ occurs on the oxygen atoms of the carbonyl groups leading to a compact configuration. Meanwhile, deprotonated molecules have higher DTCCSN2 values due to their elongated structures in the gas phase. Therefore, DTCCSN2 values of isomers in SOA mixtures depend strongly on the mode of ionization in ESI. Additionally, PSOA monomers and dimers exhibit larger DTCCSN2 values (1-4%) than their LSOA counterparts owing to more rigid structures. A cyclobutane ring is present with functional groups pointing in opposite directions in PSOA compounds, as compared to noncyclic flexible LSOA structures, forming more compact ions in the gas phase. Lastly, we investigated the effects of direct photolysis on the chemical transformations of selected individual PSOA components. We use IM-MS to reveal structural changes associated with aerosol aging by photolysis. This study illustrates the detailed molecular and structural descriptors for the detection and annotation of structural isomers in complex SOA mixtures.

Membrane Permeation and Separation in Gas and Liquid Phase

Membrane Permeation and Separation in Gas and Liquid Phase

The polar and nonpolar interfaces influenced of magnetism in LaMnO3-based superlattices.

The interface of perovskite heterostructures has been shown to exhibit various electronic and magnetic phases such as two-dimensional electron gas, magnetism, superconductivity, and electronic phase separation. These rich phases are expected due to the strong interplay between spin, charge, and orbital degree of freedom at the interface. In this work, the polar and nonpolar interfaces are designed in LaMnO3-based (LMO) superlattices to investigate the difference in magnetic and transport properties. For the polar interface in a LMO/SrMnO3 superlattice, a novel robust ferromagnetism, exchange bias effect, vertical magnetization shift, and metallic behaviors coexist due to the polar catastrophe, which results in a double exchange coupling effect in the interface. For the nonpolar interface in a LMO/LaNiO3 superlattice, only the ferromagnetism and exchange bias effect characteristics exist due to the polar continuous interface. This is attributed to the charge transfer between Mn3+ and Ni3+ ions at the interface. Therefore, transition metal oxides exhibit various novel physical properties due to the strong correlation of d electrons and the polar and nonpolar interfaces. Our observations may provide an approach to further tune the properties using the selected polar and nonpolar oxide interfaces.

MALDI TIMS IMS of Disialoganglioside Isomers─GD1a and GD1b in Murine Brain Tissue.

Gangliosides are acidic glycosphingolipids, containing ceramide moieties and oligosaccharide chains with one or more sialic acid residue(s) and are highly diverse isomeric structures with distinct biological roles. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) enables the untargeted spatial analysis of gangliosides, among other biomolecules, directly from tissue sections. Integrating trapped ion mobility spectrometry with MALDI IMS allows for the analysis of isomeric lipid structures in situ. Here, we demonstrate the gas-phase separation and identification of disialoganglioside isomers GD1a and GD1b that differ in the position of a sialic acid residue, in multiple samples, including a standard mixture of both isomers, a biological extract, and directly from thin tissue sections. The unique spatial distributions of GD1a/b (d36:1) and GD1a/b (d38:1) isomers were determined in rat hippocampus and spinal cord tissue sections, demonstrating the ability to structurally characterize and spatially map gangliosides based on both the carbohydrate chain and ceramide moieties.

Separation techniques for intact antibody analysis by mass spectrometry

The possibilities to directly couple different separation methods with mass spectrometry (MS) for the analysis of intact proteins has attracted significant attention over the last decade. While sample preparation is critical for MS analyses, coupling an efficient separation method before MS can significantly improve the ability to resolve protein heterogeneity and reveal intact masses or higher-order structure information (e.g., PTM or conformation changes). To that end, this review focuses on common online separation techniques coupled with MS detection to detect antibodies or large proteins with a focus on biopharmaceutical applications. An overview of liquid chromatography modes, such as reversed-phase, size-exclusion, mixed-mode, hydrophobic interaction, and ion-exchange chromatography will be discussed, along with electrophoretic separation, gas-phase separation using ion-mobility and other next-generation tools. Finally, the application space within the biopharmaceutical industry will be discussed along with how improvements for separation techniques before MS detection can ultimately help characterize charge-, size-, or hydrophobic variants of novel biotherapeutics throughout all stages of drug development.

Optimization of converting process for matte of oxidized nickel ores and sulfide copper ores joint smelting based on thermodynamic simulation

The paper presents the results obtained in the thermodynamic modeling of converting copper-nickel matte (11.3 wt.% Ni + Cu + + Co, 61.5 wt.% Fe, 25.9 wt.% S) produced by joint smelting of oxidized nickel ore and sulfide copper ore. Calculations were made in the approximation of ideal molecular solutions using the HSC Chemistry software package (Outotec Research Oy, Finland). The possibility of low-iron matte, converter slag and gas phase separation was shown. Estimated conditional equilibrium constants of exchange reactions between low-iron matte and slag (KNi/Fe = 0.004÷0.005, KCo/Fe = 0.056÷0.099) are close to ideal values. Statistical data processing was carried out using the mathematical experiment planning method. The converting temperature (t = 1100÷1300 °C) and iron and sulfur oxidation completeness level (q = 0.9÷1.0) determining the air and flux (SiO2) consumption were chosen as the factors to study. Obtained mathematical models of the process were used for its optimization. It was shown that the best converting performance can be achieved at t = 1150 °С and q = 0.950 when the low-iron matte contains 70.7 wt.% Ni + Cu + Co. At a yield of 8.74 % of the charge mass, the nickel, copper and cobalt recovery rates are 67.9, 97.9 and 9.1 %, respectively. The supposed air consumption (145.1 m3 (under normal conditions) per 100 kg of matte) and SiO2 (34.4 kg per 100 kg of matte) as well as slag yield (89.1 % of the charge mass) are close to working regime parameters. The results of the study confirm the possibility of cost-effective processing of poor copper-nickel matte and after experimental verification they can be used to develop automation flowcharts for converter departments at existing and designed production facilities.

Improving Ion Mobility Mass Spectrometry of Proteins through Tristate Gating and Optimization of Multiplexing Parameters.

Coupling drift tube ion mobility (IM) to Fourier transform mass spectrometry (FT-MS) affords the opportunity for gas-phase separation of ions based on size and conformation with high-resolution mass analysis. However, combining IM and FT-MS is challenging because ions exit the drift tube on a much faster time scale than the rate of mass analysis. Fourier transform (FT) and Hadamard transform multiplexing methods have been implemented to overcome the duty-cycle mismatch, offering new avenues for obtaining high-resolution, high-mass-accuracy analysis of mobility-selected ions. The gating methods used to integrate the drift tube with the FT mass analyzer discriminate against the transmission of large, low-mobility ions owing to the well-known gate depletion effect. Tristate gating strategies have been shown to increase ion transmission for drift tube IM-FT-MS systems through implementation of dual ion gating, controlling the quantity and timing of ions through the drift tube to reduce losses of slow-moving ions. Here we present an optimized set of multiplexing parameters for tristate gating ion mobility of several proteins on an Orbitrap mass spectrometer and further report parameters for increased ion transmission and mobility resolution as well as decreased experimental times from 15 min down to 30 s. On average, peak intensities in the arrival time distributions (ATDs) for ubiquitin increased 2.1× on average, while those of myoglobin increased by 1.5× with a resolving power increase on average of 11%.

High-Field Asymmetric Waveform Ion Mobility Spectrometry Interface Enhances Parallel Reaction Monitoring on an Orbitrap Mass Spectrometer.

High-field asymmetric waveform ion mobility spectrometry (FAIMS) enables gas-phase separations on a chromatographic time scale and has become a useful tool for proteomic applications. Despite its emerging utility, however, the molecular determinants underlying peptide separation by FAIMS have not been systematically investigated. Here, we characterize peptide transmission in a FAIMS device across a broad range of compensation voltages (CVs) and used machine learning to identify charge state and three-dimensional (3D) electrostatic peptide potential as major contributors to peptide intensity at a given CV. We also demonstrate that the machine learning model can be used to predict optimized CV values for peptides, which significantly improves parallel reaction monitoring workflows. Together, these data provide insight into peptide separation by FAIMS and highlight its utility in targeted proteomic applications.

Effect of produced carbon dioxide on multiphase fluid flow modeling of carbonate acidizing

A two-scale continuum (TSC) numerical model is used at pore and Darcy scales to model and optimize the matrix acidizing dissolution process. During matrix acidizing process in carbonate reservoir, the solubility of carbon dioxide, as one of the hydrochloric acid/calcite reaction products, is limited, which leads to the formation of a separate gas phase in the reservoir based on pressure and temperature. The presence of this free gas has nonlinear effect on the fluid flow and phase distribution in porous media due to the alteration in the relative permeability of the injected/spent acid. Density and viscosity of the spent acid will also be changed. Ignoring these effects on TSC model can reduce the accuracy of the final results compared to similar laboratory studies. The significance of our study is to examine and apply the nonlinear effects of produced carbon dioxide on wormhole propagation, dissolution patterns, and breakthrough curves at different injection rates of the acid. The innovation presented in this study is the evaluation of the effect of the presence of the gaseous carbon dioxide produced during the hydrochloric acid and calcite reaction on the relative permeability of the injected acid. This effect has been numerically investigated and solved along with the governing equations of the matrix acidizing at different time steps. In our work, The TSC model is coupled with a nonlinear relative permeability model to consider the effect of free carbon dioxide. Density, viscosity, and solubility correlations are also coupled with TSC model to update fluid properties during acid propagation and acid/rock interactions. The final results show that the neglecting of free gas affects the accuracy of wormhole propagation estimation. The model shows better agreement with the experimental data to predict the rock dissolution patterns and wormhole breakthrough. By considering free gas, the model can track thicker wormholes due to the free gas blockage and the slower acid/rock reaction rate. Our approach showed that isothermal models are not accurate enough to predict the change in carbon dioxide solubility at higher temperatures. Reduction in solubility affects the acid's relative permeability and increases the volume of acid required for the breakthrough. Hence, the developed model improves our knowledge of wormhole propagation during carbonate acidizing.

Dry ice propellant for electric propulsion with triple-point storage

Dry ice has been proposed as a propellant for electric propulsion, as its use may facilitate the realization of a low-cost propulsion system compared to that based on a xenon propellant. In addition, dry ice can be obtained from space (e.g., from the atmosphere of Mars) and human exhalation. This study thus conducted experiments with dry ice storage and carbon dioxide gas supply using triple-point storage. With this method, a constant tank pressure and flow rate was achieved without the application of regulators or control valves. However, the triple-point state was unexpectedly halted, even though solid dry ice remained in the tank. An internal visual observation revealed that the solid phase was surrounded by the liquid phase, which prevented the solid phase from melting. Therefore, heat conduction fins were installed in the tank to enhance the melting process, which successfully extended the triple-point duration. The supply system was applied successfully to the operation of a 1 kW Hall thruster. Furthermore, a mathematical model for estimating the phase characteristics in the tank was developed, with an in-orbit operation analyzed based on the experimental results. The heat input to the tank and the mass flow rate or enthalpy to the thruster determined the phase characteristics in the tank, which means that implementing a thermal design that considers the flow rate to the thruster is crucial. The simulation demonstrated that dry ice can be consumed by controlling the three phases in the tank using an electrical heater. A gas phase separator concept consisting of the heat conduction fins and capillary screen mesh was proposed for orbital microgravity operation.

Size-Based Proteome Fractionation through Polyacrylamide Gel Electrophoresis Combined with LC-FAIMS-MS for In-Depth Top-Down Proteomics.

The combination of liquid chromatography (LC) and gas-phase separation by field-asymmetric ion mobility spectrometry (FAIMS) is a powerful proteoform separation system for top-down proteomics. Here, we present an in-depth top-down proteomics workflow, GeLC-FAIMS-MS, in which a molecular-weight-based proteome fractionation approach using SDS-polyacrylamide gel electrophoresis is performed prior to LC-FAIMS-MS. Since individual bands and their corresponding mass ranges require different compensating voltages (CVs), the MS parameters for each gel band and CV were optimized to increase the number and reliability of proteoform identifications further. We developed an easy-to-implement and inexpensive procedure combining the earlier established Passively Eluting Proteins from Polyacrylamide gels as Intact species (PEPPI) protocol with an optimized Anion-Exchange disk-assisted Sequential sample Preparation (AnExSP) method for the removal of stains and SDS. The protocol was compared with a methanol-chloroform-water (MCW)-based protein precipitation protocol. The results show that the PEPPI-AnExSP procedure is better suited for the identification of low-molecular-weight proteoforms, whereas the MCW-based protocol showed advantages for higher-molecular-weight proteoforms. Moreover, complementary results were observed with the two methods in terms of hydrophobicity and isoelectric points of the identified proteoforms. In total, 8500 proteoforms could be identified in a human proteome standard, showing the effectiveness of the gel-based sample fractionation approaches in combination with LC-FAIMS-MS.

Novel Online Three-Dimensional Separation Expands the Detectable Functional Landscape of Cellular Phosphoproteome.

Protein phosphorylation is a prevalent post-translational modification that regulates essentially every aspect of cellular processes. Currently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an extensive offline sample fractionation and a phosphopeptide enrichment method is a best practice for deep phosphoproteome profiling, but balancing throughput and profiling depth remains a practical challenge. We present an online three-dimensional separation method for ultradeep phosphoproteome profiling that combines an online two-dimensional liquid chromatography separation and an additional gas-phase separation. This method identified over 100,000 phosphopeptides (>60,000 phosphosites) in HeLa cells during 1.5 days of data acquisition, and the largest HeLa cell phosphoproteome significantly expanded the detectable functional landscape of cellular phosphoproteome.

Numerical Model of Heat- and Mass-Transfer and Disperse Phase Separation in High-Speed Dispersed-Annular Gas and Liquid Flows

Numerical Model of Heat- and Mass-Transfer and Disperse Phase Separation in High-Speed Dispersed-Annular Gas and Liquid Flows

Molecular networking and collision cross section prediction for structural isomer and unknown compound identification in plant metabolomics: a case study applied to Zhanthoxylum heitzii extracts

Mass spectrometry-based plant metabolomics allow large-scale analysis of a wide range of compounds and the discovery of potential new active metabolites with minimal sample preparation. Despite recent tools for molecular networking, many metabolites remain unknown. Our objective is to show the complementarity of collision cross section (CCS) measurements and calculations for metabolite annotation in a real case study. Thus, a systematic and high-throughput investigation of root, bark, branch, and leaf of the Gabonese plant Zhanthoxylum heitzii was performed through ultra-high performance liquid chromatography high-resolution tandem mass spectrometry (UHPLC-QTOF/MS). A feature-based molecular network (FBMN) was employed to study the distribution of metabolites in the organs of the plants and discover potential new components. In total, 143 metabolites belonging to the family of alkaloids, lignans, polyphenols, fatty acids, and amino acids were detected and a semi-quantitative analysis in the different organs was performed. A large proportion of medical plant phytochemicals is often characterized by isomerism and, in the absence of reference compounds, an additional dimension of gas phase separation can result in improvements to both quantitation and compound annotation. The inclusion of ion mobility in the ultra-high performance liquid chromatography mass spectrometry workflow (UHPLC-IMS-MS) has been used to collect experimental CCS values in nitrogen and helium (CCSN2 and CCSHe) of Zhanthoxylum heitzii features. Due to a lack of reference data, the investigation of predicted collision cross section has enabled comparison with the experimental values, helping in dereplication and isomer identification. Moreover, in combination with mass spectra interpretation, the comparison of experimental and theoretical CCS values allowed annotation of unknown features. The study represents a practical example of the potential of modern mass spectrometry strategies in the identification of medicinal plant phytochemical components.

Equal Quality Distribution of Two-Phase Fluid by Isokinetic Principle

Summary In thermal recovery of heavy oil, phase separation often occurs when a steam-water stream turns to branches in a junction and distributor, thereby resulting in a significant quality deviation between branches. Although a lot of efforts have been made during the past decades, the problem is still not well solved. Inspired by the principle of the isokinetic probe, this paper builds a new model of distribution. The major change is that the inner space of the main pipe is isolated into fan-shaped isokinetic flow channels, each connecting to a side branch. Flow control devices are installed at the outlet of each branch. Moreover, a swirler is used to convert the incoming flow pattern into a uniform swirling gas core-annular flow before the new isokinetic dividing system. Computational fluid dynamics (CFD) simulations were conducted to reveal the characteristics of gas-liquid two-phase flow within the distributor. The characteristics of both under isokinetic and nonisokinetic flow conditions were analyzed. The most interesting result is that once the uniform swirling gas core-annular flow is formed, liquid film flow becomes very stable and is almost unaffected by the operation deviations from the isokinetic condition, whereas gas flow is much more sensitive to the deviations. The more deviation of isokinetic condition, the more deflection of gas flow or phase separation will take place and the greater quality deviation will be. Air-water two-phase flow experiments were also conducted to verify the CFD results.

Ultra-fast screening of free fatty acids in human plasma using ion mobility mass spectrometry.

Free fatty acids are involved in many metabolic regulations in the human body. In this work, an ultra-fast screening method was developed for the analysis of free fatty acids using trapped ion mobility spectrometry coupled with mass spectrometry. Thirty-three free fatty acids possessing different unsaturation degrees and different carbon chain lengths were baseline separated and characterized within milliseconds. Saturated, monounsaturated, and polyunsaturated free fatty acids showed different linearities between collision cross-section values and m/z. The establishment of correlations between structures and collision cross-section values provided additional qualitative information and made it possible to determine free fatty acids which were out of the standards pool but possessed the confirmed linearity. The gas-phase separation made the quantitative analysis reliable and repeatable at a much lower time cost than chromatographic methods. The sensitivity was comparable to and even better than the reported results. The method was validated and applied to profiling free fatty acids in human plasma. Saturated free fatty acids abundance in the fasting state was found to be lower than that in the postprandial state, while unsaturated species abundance was found higher. The method was fast and robust with minimum sample pretreatment, so it was promising in the high-throughput screening of free fatty acids.

Leveraging Parameter Dependencies in High-Field Asymmetric Waveform Ion-Mobility Spectrometry and Size Exclusion Chromatography for Proteome-wide Cross-Linking Mass Spectrometry.

Ion-mobility spectrometry shows great promise to tackle analytically challenging research questions by adding another separation dimension to liquid chromatography–mass spectrometry. The understanding of how analyte properties influence ion mobility has increased through recent studies, but no clear rationale for the design of customized experimental settings has emerged. Here, we leverage machine learning to deepen our understanding of field asymmetric waveform ion-mobility spectrometry for the analysis of cross-linked peptides. Knowing that predominantly m/z and then the size and charge state of an analyte influence the separation, we found ideal compensation voltages correlating with the size exclusion chromatography fraction number. The effect of this relationship on the analytical depth can be substantial as exploiting it allowed us to almost double unique residue pair detections in a proteome-wide cross-linking experiment. Other applications involving liquid- and gas-phase separation may also benefit from considering such parameter dependencies.