Porous Column Research Articles

Deep Single-Shot NanoLC-MS Proteome Profiling with a 1500 Bar UHPLC System, Long Fully Porous Columns, and HRAM MS.

This study demonstrates how the latest ultrahigh-performance liquid chromatography (UHPLC) technology can be combined with high-resolution accurate-mass (HRAM) mass spectrometry (MS) and long columns packed with fully porous particles to improve bottom-up proteomics analysis with nanoflow liquid chromatography–mass spectrometry (nanoLC-MS) methods. The increased back pressures from the UHPLC system enabled the use of 75 μm I.D. × 75 cm columns packed with 2 μm particles at a typical 300 nL/min flow rate as well as elevated and reduced flow rates. The constant pressure pump operation at 1500 bar reduced sample loading and column washing/equilibration stages and overall overhead time, which maximizes MS utilization time. The versatility of flow rate optimization to balance the sensitivity, throughput with sample loading amount, and capability of using longer gradients contributes to a greater number of peptide and protein identifications for single-shot bottom-up proteomics experiments. The routine proteome profiling and precise quantification of >7000 proteins with single-shot nanoLC-MS analysis open possibilities for large-scale discovery studies with a deep dive into the protein level alterations. Data are available via ProteomeXchange with identifier PXD035665.

Comparative analysis of trilobal capillary-channeled polymer fiber columns with superficially porous and monolithic phases toward reversed-phase protein separations.

A trilobal capillary-channeled polymer fiber stationary phase is evaluated for its performance for intact protein separations under reversed-phase high-performance liquid chromatography conditions. The separation quality, operational characteristics, and protein dynamic loading capacity on the fiber phases are compared to commercially-available superficially porous and monolithic columns. The trilobal or "y-shaped" polypropylene fiber phase was employed to separate a synthetic mixture of five proteins (having diverse chemistries and molecular weights). The separation quality was evaluated based on the resolution, peak heights/recoveries, peak widths, and peak areas. The present work illustrates the unique ability to operate at higher linear velocities (47.5mm/s) while maintaining lower back pressures (∼4 MPa), faster separation times (<8 min), and faster gradient rates using the fiber columns while yielding comparable chromatographic performance to the commercial columns. The separations employing the commercial stationary phases operate at lower linear velocities (∼3.0 mm/s), higher back pressures (∼9 MPa), require longer separation times (10 min), and require slightly higher compositions of organic mobile phase to effect protein elution. Likewise, based on breakthrough loading analysis of lysozyme and bovine serum albumin, the trilobal, polypropylene C-CP fiber column stationary phases demonstrate 3-9X greater binding capacities on a bed volume basis versus the commercial columns.

Porous capillary monolithic column coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry for fast and effective separation and determination of estrogens

In this work, a porous capillary monolithic column was simply prepared by in situ thiol-alkyne click polymerization of dipentaerythritol hexakis (3-mercaptopropionate) and dimethyl dipropargylmalonate in fused-silica capillary. The capillary monolithic column shows excellent permeability, high porosity, and thoiether-rich groups, thereby, a high-efficient capacity for trace estrogens from complex samples are obtained via electron-donor-acceptor π-π interaction and hydrophobic interaction. The highest adsorption efficiency for estrogens is achieved at pH = 7.0 with a flow rate of 0.200 mL min−1. The superior adsorption capacities of the as-prepared capillary column for eight estrogens range from 0.092 mg m−1 to 0.31 mg m−1. A simple, reliable, and sensitive method for the determination of eight estrogens in biological and environmental samples is developed using the monolithic polymer as in-tube solid-phase microextraction coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS), and the total instrumental analysis time for the SPME-UPLC-MS/MS procedures was about 60 min per sample. The developed method shows a wide linear range (0.0500–5.00 μg L−1), and low limits of detection (5.34–9.63 ng L−1) for estrogens. The concentrations of estrogens in serum, urine, and pond water samples are found to be no more than 3.69, 0.741, and 1.04 μg L−1, respectively, and the satisfying recoveries for the eight estrogens range from 80.3% to 113% with relative standard deviations (n = 5) of 1.5–9.4%. The established method is highly potential for extraction and analysis of ultratrace target estrogens in complex matrices, such as biological and environmental samples.

A simple UPLC-MS/MS assay with a core-shell column for the determination of exemestane in human plasma for clinical application.

Exemestane is one of the aromatase inhibitors and has been used to treat breast cancer by lowering estrogen levels. Accurate quantification of exemestane is important to set an optimal dose, and thus a simple assay for exemestane is developed by ultra-performance liquid chromatography with tandem mass spectrometer. Exemestane was extracted from human plasma samples (100 μL) by simple protein precipitation with acetonitrile/methanol (1/1, v/v). Interference peaks observed close to the elution of exemestane led us to use a core shell column for higher selectivity instead of totally porous columns. The extracts were chromatographed on CORTECS UPLC C18, under a gradient elution at a flow rate of 0.25 mL/min and detected in the selected reaction monitoring. Validation parameters were assessed in accordance with the bioanalytical guidelines using quality control samples. Exemestane in human plasma was quantifiable from 0.5 to 50 ng/mL with high extraction recovery and minimal matrix effects. Hemolyzed or hyperlipemic plasma did not impact the exemestane assay. Exemestane was stable in human plasma for 392 days at -15°C or below. The developed assay was robust and successfully applied to quantifying exemestane concentrations in human plasma to support a clinical trial.

Arsenic extraction from seriously contaminated paddy soils with ferrihydrite-loaded sand columns

Reductive dissolution of iron oxides in flooded paddy soils is the most important cause of arsenic (As) release into soil aqueous solution and thus entry into rice. From the perspective of soil cleanup, however, As release under flooded condition could facilitate labile As removal. In this study, a porous column pre-loaded with ferrihydrite (Fh) was constructed, and its efficiency of soil As extraction was investigated using a purpose-designed mesocosm coupled with diffusive gradients in thin films (DGT) for in situ visualization. With Fh-column deployed in aqueous solution, >90% removal of As(III) was achieved within 5 days at initial As (100 mg L−1) of two orders of magnitude higher than in most paddy soil solutions (1–1538 μg L−1). By applying Fh-column in a seriously contaminated paddy soil (102 mg As kg−1), porewater As showed stepwise decreases from 2727 μg L−1 to 129–1455 μg L−1 at a distance-dependent manner over four intermittent extractions during 91 days. Soil DGT-As exhibited similar spatiotemporal changes to porewater As. After four extractions, 17.8% of total soil As was removed by Fh-column in a 10 cm radius range on average and ∼1/3 of As bound to amorphous and crystalline Fe/Al oxides was depleted, which accounted for 88.7% of decline in total soil As. With the post-extracted soil, a 48% lower As accumulation in rice seedlings and a 65% decline in bulk soil DGT-As were attained. This study provides a conceptual foundation for rapid removal of high soluble As by Fh-columns from flooded soils, improving seriously As-contaminated paddies to sustainable resources for safe food production.

A new stationary phase based on porous graphene for capillary gas chromatography

AbstractThis work reported the preparation and evaluation of a 2D porous graphene as the stationary phase for gas chromatography with high‐resolution performance from non‐polar to polar structural isomers. As a result, the dynamically coated porous graphene capillary column has a film thickness of about 16 μm. After aging treatment at different temperatures, the porous graphene capillary column exhibited high thermal stability up to 300°C. In addition, the porous graphene capillary column has good column repeatability and reproducibility. The retention time RSDs are 2.61–3.90% (n = 3) during the days and 4.58–4.78% (n = 3) column‐to‐column. This work demonstrates the advantageous separation performance of a good potential for the porous graphene as a new stationary phase for gas chromatography analysis.

The Synthesis of FeCl3-Modified Char from Phoenix Tree Fruit and Its Application for Hg0 Adsorption in Flue Gas

A sample of FeCl3-modified phoenix tree fruit char (MPTFC) was prepared using pyrolysis and a facile chemical immersion method; it was proposed as an effective sorbent for Hg0 adsorption in flue gas. The BET, SEM, FTIR, and XPS methods were adopted for the characterizations of the sorbents, and a series of Hg0 adsorption tests were conducted on a bench-scale Hg0 removal setup in the lab. The morphological analysis of the sorbent indicated that the hollow fiber in phoenix tree fruit (PTF) shifted to organized directional porous tubular columns in phoenix tree fruit char (PTFC) after pyrolysis. The surface area of MPTFC increased slightly in comparison with PTF and PTFC. The MPTFC showed excellent performance for Hg0 adsorption at 200 °C in flue gas ambiance, and the Hg0 removal efficiency approached 95% with 5% (wt.%) FeCl3 modification. The presence of O2 may help to activate the MPTFC for Hg0 adsorption in flue gas, thus greatly promoting Hg0 adsorption capability. NO had a positive effect on Hg0 adsorption, while the presence of SO2 in flue gas restrained Hg0 adsorption by MPTFC. Functional groups, such as C-Cl and Fe-O, were successfully decorated on the surface of PTFC by FeCl3 modification, which contributed greatly to Hg0 adsorption. In addition, C=O, lattice oxygen (Oα), and adsorbed oxygen (Oβ) also contributed to Hg0 adsorption and oxidization.

Effects of humic acid and kaolinite on copper transport in water‐saturated porous media

AbstractMobile organic macromolecules and inorganic particles may act as carriers of strongly sorbing contaminants in subsurface materials, posing a potential facilitated transport risk. This study examined the influence of humic acid (HA) and kaolinite colloid on copper ion transport in saturated porous media. Column experiments were conducted to investigate the migration behavior and interactions of HA, kaolinite and copper under different experimental conditions in saturated porous media. The results showed that the individual presence of HA promoted the transport of Cu. However, the mixture of kaolinite and HA has less effect on Cu migration than HA alone. The presence of Cu reduced the mobility of kaolinite through the saturated porous media sand column by increasing the deposition rate of kaolinite. The transport of kaolinite increased significantly in the presence of HA, while kaolinite slightly decreased HA transport in the sand column. Compared with kaolinite, HA has a stronger ability to desorb copper from copper‐bearing sand. Considering the presence of kaolinite and HA, this study provides a reference for the fate, migration and risk assessment of heavy metal pollutants.

Targeted analysis of sugar phosphates from glycolysis pathway by phosphate methylation with liquid chromatography coupled to tandem mass spectrometry

Monitoring the glycolysis pathway remains an analytical challenge as most metabolites involved are sugar phosphates. Structural similarity, instability, high polarity, and rich negative charges of sugar phosphates make LC-MS based analysis challenging. Here, we developed an improved workflow integrating uniformly 13C-labeled yeast metabolite extract, TiO2-based enrichment, differential stable isotope labeling phosphate methylation, porous graphic carbon column, and selected reaction monitoring acquisition. Uniformly 13C labeled yeast metabolite extract was used as internal standards while differential stable isotope labeled sugar phosphates worked as calibrants. The established method was validated in human plasma, platelet and cultured HeLa cells. The limits of quantification ranged between 0.25 and 0.54 pmol on column. The method was adapted and its applicability tested for human platelets in which activation with collagen-related peptide (CRP) clearly showed the upregulation of some SPx metabolites. The results document that this newly established method can be successfully used to monitor glycolysis in different biological samples. As an extension, more phosphorylated and carboxylated metabolites from the central carbon metabolism (pentose phosphate cycle, TCA cycle) were tested as well. This method showed superior performance, especially for multiple phosphorylated and carboxylated metabolites. For quantitative purpose, the concept of SPx in three sets (12C-analytes, U-13C-IS, deuterated calibrants) has the potential to be adapted for more anionic metabolites.

Kinetic performance comparison of superficially porous, fully porous and monolithic reversed-phase columns by gradient kinetic plots for the separation of protein biopharmaceuticals

To find the best performing column for the analysis of protein-based biopharmaceuticals is a significant challenge as meanwhile numerous modern columns with distinct stationary phase morphologies are available for reversed-phase liquid chromatography. Especially when besides morphology also several other column factors are different, it is hard to decide about the best performing column a priori. To cope with this problem, in the present work 13 different reversed-phase columns dedicated for protein separations were systematically tested by the gradient kinetic plot method. A comprehensive comparison of columns with different morphologies (monolithic, fully porous and superficially porous particle columns), particle sizes and pore diameters as well as column length was performed. Specific consideration was also given to various monolithic columns which recently shifted a bit out of the prime focus in the scientific literature. The test proteins ranged from small proteins starting from 12 kDa, to medium sized proteins (antibody subunits obtained after IdeS-digestion and disulphide reduction) and an intact antibody. The small proteins cytochrome c, lysozyme and β-lactoglobulin could be analysed with similar performance by the best columns of all three column morphologies while for the antibody fragments specific fully porous and superficially porous particle columns were superior. A 450 Å 3,5 µm superficially porous particle column showed the best performance for the intact antibody while a 1.7 µm fully porous particle column with 300 Å showed equivalent performance to the best superficially porous column with thin shell and 400 Å pore size for proteins between 12 and 25 kDa. While the majority of the columns had C4 bonding chemistry, the silica monolith with C18 bonding and 300 Å mesopore size approximated the best performing particle columns and outperformed a C4 300 Å wide-pore monolith. The current work can support the preferred choice for the most suitable reversed-phase column for protein separations.

Optimization of flow in additively manufactured porous columns with graded permeability

AbstractChemical engineering systems often involve a functional porous medium, such as in catalyzed reactive flows, fluid purifiers, and chromatographic separations. Ideally, the flow rates throughout the porous medium are uniform, and all portions of the medium contribute efficiently to its function. The permeability is a property of a porous medium that depends on pore geometry and relates flow rate to pressure drop. Additive manufacturing techniques raise the possibilities that permeability can be arbitrarily specified in three dimensions, and that a broader range of permeabilities can be achieved than by traditional manufacturing methods. Using numerical optimization methods, we show that designs with spatially varying permeability can achieve greater flow uniformity than designs with uniform permeability. We consider geometries involving hemispherical regions that distribute flow, as in many glass chromatography columns. By several measures, significant improvements in flow uniformity can be obtained by modifying permeability only near the inlet and outlet.

Molecular parameters including fluorination program order during hierarchical helical self-organization of self-assembling dendrons

Primary structure endows tertiary structure while tertiary structure determines function. This fundamental principle is responsible for the generation of high order and precise functions in both biological assemblies including giant and mega proteins and nucleic acids as well as in metals generated from only few atoms. However, this size-independent ability to generate high order and very precise functions is not yet accessible in non-biological assemblies that use the same principles for their hierarchical self-organization. Here we report a study investigating the role of the molecular parameters on the hierarchical self-organizations of helical columnar assemblies produced from the column-forming self-assembling dendron (4-3,4-3,5)-X with a linear or branched hydrogenated or linear semifluorinated alkyl groups while apex is -CO2CH3 or -CH2OH. A combination of differential scanning calorimetry, small and wide-angle powder and oriented fiber X-ray diffraction experiments together with helical diffraction theory, 2-D and 3-D electron density maps were employed in these structural analysis experiments. They demonstrated that H-bonding at the apex of the self-assembling dendron enhanced the order of the helical columns by comparison with the order of supramolecular helical columns based on dendrons containing an ester group at their apex. This was the case for both linear and branched alkyl groups at the periphery of the self-assembling dendron. Unexpectedly, self-assembling dendrons containing semifluorinated alkyl groups on their periphery and H-bonding groups at their apex increase even more the order of their supramolecular perfluorinated porous helical column. In all cases helix is mediated by the aromatic part of the dendron but hierarchically influenced both by the apex and peripheral groups. A combination of branched alkyl groups with H-bonding at the apex produced a new mechanism to transform helical columns assembled from the column-forming (4-3,4-3,5)-X self-assembling dendron into spherical assemblies, organized from conical dendron conformers, forming an A15 Frank-Kasper phase.

Porous layer open tubular nano liquid chromatography directly coupled to electron ionization mass spectrometry

A 25 µm i.d x 1.2 m length PS-DVB porous layer open tubular column (PLOT) was prepared and assessed in the configuration of a nano liquid chromatography coupled to an electron ionization mass spectrometry system (OT-nanoLC-EI-Ms), via the direct insertion of the column outlet into the ionization source. The developed system's operational parameters were comprehensively studied, and the setup performance was investigated employing both unidimensional and column switching configurations. As a result, the OT-nanoLC-EI-MS system demonstrated competitive applicability in separating non-amenable ESI compounds, such as polyaromatic hydrocarbons (PAHs) and non-amenable GC compounds such as thermolabile pesticides. Furthermore, with excellent chromatographic performance, the PLOT columns can work under more compatible EI-detection conditions — such as the elution with 100% organic solvent. For example, PAHs retention factors ranged between 1.5 and 2.2 for 100% MeCN mobile phase, and more than 33,000 plates per meter for naphthalene at 50 nL/min flow rate. In analyzing thermolabile pesticides, the column switching PLOT-nanoLC-EI-MS system provided LODs of 25 µg/L, demonstrating suitable intra e interday reproducibility (% RSD < 13%, n = 3), and possibilities the direct injection of raw samples with suitable robustness.

Development and application of a fast ultra-high performance liquid chromatography-trapped ion mobility mass spectrometry method for untargeted lipidomics

The alteration of lipid profile in biological specimens, such as plasma, mirrors abnormalities in their homeostasis and offers pivotal information for disease comprehension. Fast analytical methods are needed to highlight changes in plasma lipid profile and deliver rapid results. In this study we developed a fast reversed phase ultra high performance liquid chromatography-trapped ion mobility mass spectrometry (RP-UHPLC-TIMS-MS) method for untargeted lipidomics. A short, narrow-bore fully porous particle CSH column (50 mm × 2.1 mm, 1.7 µm) was used, and by selecting appropriate flow rate, temperature and gradient conditions, the total analysis time was reduced from 20 to 4 min. TIMS was operated in parallel accumulation serial fragmentation mode (PASEF) which allowed to select multiple precursors for MS/MS and separate co-eluting lipids based on their different mobility. Lipid annotation was performed by rule-based approach, comparison with LipidBlast spectral library and manual data curation, by taking into account class-specific fragmentation pattern, accurate mass, adduct form, retention behavior in RP and comparison of their collision cross-section (CCS) values for increased confidence. 306 unique lipids from 21 subclasses were annotated from 20 µL of plasma, while their concentration was estimated by class-specific deuterated internal standards. The analytical method was validated and finally applied to elucidate the alteration of plasma lipid profiles in a small cohort of amyotrophic lateral sclerosis (ALS) patients. Univariate and multivariate statistics evidenced significant differences with respect to control patients, particularly in the levels of ether linked lipids (PC-O, PE-O, PE-P and LPC-O), sphingolipids (Ceramides), and triacylglycerols, showing the usefulness of this fast approach in providing accurate and rapid results with respect to longer (≥15 min) untargeted UHPLC-HRMS methods.

Visualization research on influencing factors of flat heat pipes

Flat heat pipes can effectively spread a concentrated high power heat source in a small region into a larger heat dissipation area, which is widely used in the thermal management of electronic devices. In this paper, two different sintered copper powder wick structures are designed to study the effect of porous column height on the heat transfer performance. The results show that the best performance is achieved at the 30% filling ratio under the 15 ℃ cooling water with all the porous columns contacting with the condenser. The heat power is 312.7 W and the thermal resistance is 0.192 ℃/W. As the cooling water temperature increases, the evaporation rate increases, resulting in a decrease in the thermal resistance. But the decrease in temperature difference causes the decline in heat dissipation power. Through the visual observation, it is found that the porous column contacting with the condenser can not only play the role of support and liquid reflow pathway, but also serve as an effective evaporation area to improve the heat transfer performance. While the low porous column cannot transport the condensed liquid and is completely immersed by the liquid under the high filling ratio, which is difficult to promote evaporation rate. In order to improve the performance at air cooling situation, an integrated heat pipe combined the flat heat pipe and fin tubes is designed, which can achieve a heat power of 259.8 W and present excellent temperature uniformity. This research provides the guidelines to optimize the heat transfer performance of porous column wick structures.

Front Cover: Comparison of the separation of proteins of wide‐ranging molecular weight via trilobal polypropylene capillary‐channeled polymer fiber, commercial superficiously porous, and commercial size exclusion columns

DOI: 10.1002/jssc.202100891 The reversed-phase (RP) separation of proteins, without size-exclusion contributions, is affected on capillary-channeled polymer (C-CP) fiber stationary phases. Polyester C-CP fibers are demonstrated to perform the rapid RP separation of peptides and proteins ranging in molecule weight of 1.44-to-660 kDa. Comparisons with commercial RP superficially porous and size exclusion columns designed for protein separations show that the across-the-board separation quality realized by the fibers is superior to the other column formats, with column material costs being far less than the standard columns.

Evaporative Drying from Hydrophilic or Hydrophobic Homogeneous Porous Columns: Consequences of Wettability, Porous Structure and Hydraulic Connectivity

Evaporative Drying from Hydrophilic or Hydrophobic Homogeneous Porous Columns: Consequences of Wettability, Porous Structure and Hydraulic Connectivity

An annular porous column (5) aromatics as anode material for lithium-ion batteries

An annular porous column (5) aromatics as anode material for lithium-ion batteries

Preparation and application of porous organic cage capillary electrochromatographic chiral column

多孔有机笼(POCs)是一种新型的具有稳定有序三维空腔结构的多孔材料。通过2-羟基-1,3,5-均苯三甲醛与1R,2R-1,2-二苯基乙二胺发生席夫碱的缩合反应,合成了一种具有羟基功能基团的单一手性POCs材料;将其均匀涂敷在毛细管壁上制成色谱柱,利用电色谱柱成功拆分了二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺4种手性化合物。探究了分离电压、缓冲溶液浓度及其pH值等因素对手性拆分的影响,获得了4种手性物质在POCs色谱柱上的最佳拆分条件。实验研究表明,二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺获得优化分离效果所需的工作电压分别为13、14、14和12 kV;二氢黄酮适宜Tris-H3PO4缓冲溶液浓度为0.075 mol/L,吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺适宜Tris-H3PO4缓冲溶液浓度为0.100 mol/L; 4种手性物质得到最佳分离效果时的pH值均为3.51。二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺均达到基线分离,分离度分别为2.99、2.10、2.58和3.59。该POCs色谱柱还成功拆分了o,m,p-碘苯胺、o,m,p-硝基苯胺两种位置异构体。该研究表明POCs手性电色谱柱具有良好的手性识别能力,是一种优秀的手性分离材料,具有很大的电色谱手性分离应用前景。

Concentration dependency of dispersion coefficient of aqueous solutions of urea and ethyl acetate in porous media

AbstractWe report new measurements of the concentration‐dependent longitudinal dispersion coefficient of aqueous urea and ethyl acetate solutions in a porous medium at a wide range of concentrations. The longitudinal dispersion coefficient was obtained by injection of a pulse of an aqueous solution of urea (or ethyl acetate) into a carrier phase flowing through a porous column and analysis of the effluent peak using the Taylor dispersion theory. The measured longitudinal dispersion coefficients for different velocities and concentrations showed an increasing trend with concentration and pore velocity. The longitudinal dispersion coefficient measurements show a power‐law relationship with the Peclet number . The results are compared with experimental data and empirical formulas available in the literature, and a reasonable agreement is achieved over the range of Peclet numbers studied.