Separation Column Research Articles

Rapid and simultaneous determination of ultrashort-, short- and long- chain perfluoroalkyl substances by a novel liquid chromatography mass spectrometry method

Per- and Polyfluoroalkyl Substances (PFAS) are a group of persistent organic pollutants that have received considerable attention from public and regulatory groups. Due to regulations of long-chain PFAS, the use of short-chain and ultrashort-chain PFAS is rapidly growing. Thus, there is an urgent need to develop quantitative methods for determining PFAS with different chain lengths in various environmental matrices. This study introduces an innovative liquid chromatography-mass spectrometry (LC-MS) system combining large volume injection (LVI) and online solid phase extraction (SPE). This system incorporates three columns: a reverse-phase (RP) column, a weak anion exchange (WAX) trap column, and a hybrid HILIC/ion-exchange (HILIC/IE) column, controlled by two valves. With valve switching, ultrashort-chain PFAS that are not retained by the RP column are enriched by the trap column, while other PFAS are separated by the RP column. The trapped ultrashort PFAS are then transferred to the HILIC/IE column for further separation. The LVI significantly enhances the method's sensitivity, allowing for rapid and simultaneous determination of ultrashort-, short- and long- chain PFAS in aqueous samples. The matrix effects from various environmental samples were evaluated, and the results indicate that this unique LC-MS method is suitable for analyzing all chain-length PFAS in various matrices, including surface water, sewage effluent, and seawater. Finally, this novel LC-MS method was applied to quantify PFAS in various water samples.

Tribal mobilization for religious identity and political space: ongoing demand for inclusion of Sarna-Tribal religion in the census of India

ABSTRACT The public mobilization of religious communities to acquire political space has been a heated discussion among scholars worldwide. Research reveals a long history of religious communities participating in political movements. However, in India, the debate on the recognition and protection of religious identity has been reduced to a discourse of minority versus majority religion. This paper examines the ongoing political mobilization by tribal communities in the state of Jharkhand and its demand for a separate religious column in the census of India. The underlying motive of this mobilization is to establish their religious identity, which is separate from both Hinduism and Christianity, and to resist the encroachment of tribal land by campaigning for tribal control over state resources through strengthening the constitutional provisions. The study focuses on tribal protests on social media platforms, in addition to the 2019 protest at Jantar Mantar, New Delhi, initiated by tribal groups demanding the Sarna-tribal religion as a legitimate religious choice in the census of India. The study used qualitative inductive analysis on data sourced through participant observation and 50 semi-structured interviews. The results prove that the ongoing protest for the recognition of the Sarna-tribal religion is stimulated by the threat to their religious identity and land rights. Additionally, social media played a crucial role in informing, mobilizing, and stimulating feelings of collective group identity.

Sequencing of Phosphorodiamidate Morpholino Oligomers by Hydrophilic Interaction Chromatography Coupled to Tandem Mass Spectrometry.

Sequencing of phosphorodiamidate morpholino oligomers (PMOs) by hydrophilic interaction chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS) is reported. The MS/MS analysis was performed using a quadrupole/time-of-flight (Q-ToF) mass analyzer and collision induced dissociation (CID) in negative ion mode. To improve MS sensitivity in negative ion mode, HILIC conditions, including the separation column, mobile phases, and MS parameters, were optimized. Using the developed HILIC-CID-MS/MS method, 100% sequence coverage was achieved for PMOs ranging from 18-mer to 25-mer. Additionally, the method was successfully applied to identifying positional isomers of n - 1 deletion impurities present in PMO drug substances.

Mitigating In-Column Artificial Modifications in High-Temperature LC-MS for Bottom-Up Proteomics and Quality Control of Protein Biopharmaceuticals.

Elevating the column temperature is an effective strategy for improving the chromatographic separation of peptides. However, high temperatures induce artificial modifications that compromise the quality of the peptide analysis. Here, we present a novel high-temperature LC-MS method that retains the benefits of a high column temperature while significantly reducing peptide modification and degradation during reversed-phase liquid chromatography. Our approach leverages a short inline trap column maintained at a near-ambient temperature installed upstream of a separation column. The retentivity and dimensions of the trap column were optimized to shorten the residence time of peptides in the heated separation column without compromising the separation performance. This easy-to-implement approach increased peak capacity by 1.4-fold within a 110 min peptide mapping of trastuzumab and provided 10% more peptide identifications in exploratory LC-MS proteomic analyses compared with analyses conducted at 30 °C while maintaining the extent of modifications close to the background level. In the peptide mapping of biopharmaceuticals, where in-column modifications can falsely elevate the levels of some critical quality attributes, the method reduced temperature-related artifacts by 66% for N-terminal pyroGlu and 63% for oxidized Met compared to direct injection at 60 °C, thus improving reliability in quality control of protein drugs. Our findings represent a promising advancement in LC-MS methodology, providing researchers and industry professionals with a valuable tool for improving the chromatographic separation of peptides while significantly reducing the unwanted modifications.

Adaptive generic model control scheme for an optimized external heat integrated air separation column using unscented kalman filter

An External Heat-Integrated Air Separation Column (E-HIASC) process is a promising air separation technology. This study focuses on the operational stability of the optimized E-HIASC process for separating nitrogen, oxygen, and argon mixtures. The operation stability of process is achieved through an Adaptive Generic Model Control (AGMC) scheme which is designed by incorporating the identified E-HIASC state-space dynamic model into the controller algorithm. The controller synthesizes the Generic Model Control (GMC) algorithm, decoupled ARX model, and Unscented Kalman Filter (UKF) algorithm to enable the auto-regression and exogenous (ARX) for model identification and the UKF algorithm to estimate time-varying parameters and compute unmeasured E-HIASC state parameters required in the GMC algorithm. A Generic Model Control (GMC) and Multivariable PID (M-PID) control schemes were also designed for benchmarking study. Simulation results show that an AGMC scheme performs better than the GMC and M-PID schemes in tracking the product concentration set point and disturbances rejection.

Computer aided flow investigation of liquid agricultural wastes

Liquid agricultural wastes serve as important fertilizers in modern agriculture but pose environmental and health risks due to high nitrogen compound content. To prevent soil and groundwater contamination, ammonia separation is required before waste application on fields. Conventional separation by stripping is difficult because of column clogging by solid waste loads. This work investigates, both experimentally and numerically, the flow behaviour of liquid agricultural waste to support the development of innovative separators based on inclined plates. The measurements were carried out in a newly developed experimental setup consisting of a liquid distributor over a plate with variable inclination angles. The influence of volumetric flow rate and inclination angles on the flow topology and liquid detachment from the edge of the plate was studied. While the impact of the flow rate was significant, no influence of the plate inclination angle could be observed. A CFD model was developed to support experimental work. Its validation with experimental data was successful, yet with some systematic deviation due to the model simplifications. The developed experimental setup and CFD model offer optimization potential for separation column internals designed for liquid agricultural wastes, with experiments providing higher accuracy and simulations offering flexibility.

Multi-targets detection via combination of multi-stimulus-response engineered bacteria and hydrogel-based separation platform

Establishing a method similar to ICP-MS that can quantitatively analyze multiple heavy metals simultaneously, conveniently, and in situ is highly anticipated. In this study, we integrated the sensing elements of multiple targets and different fluorescence reporting elements to construct an engineered Escherichia coli. When these targets are present, the engineered bacteria can emit a fluorescent signal at the corresponding wavelength. To avoid the inability to accurately distinguish and quantify the content of each target due to the overlap of fluorescence signals when multiple targets coexist, a hydrogel-based separation platform similar to a separation column was constructed. The hydrogel platform can change the detection limit (LOD) and sensitivity by adjusting the adsorption strength towards different targets, so as to realize the differentiation and recognition of their respective detection signals. The LODs of this new detection method for Cd(II), Hg(II), As(III), and Pb(II) are 1.249, 0.380, 3.917, and 0.755 μg/L, respectively. In addition, this biosensor system was applied to detect coexisting Cd(II), Hg(II), As(III), and Pb(II) in actual samples with a recovery rate of 85.61–110.30 %, which is consistent with the classical ICP-MS detection results, confirming the accuracy and reliability of the method for detecting multiple heavy metal coexisting samples.

Separation of iodate, bromide, nitrite, nitrate, and iodide in seawater by ion chromatography using 1-aminoundecyl group chemically bonded silica columns.

The separation and detection of six common inorganic anions (iodate (IO3-), bromate (BrO3-), bromide (Br-), nitrite (NO2-), nitrate (NO3-), and iodide (I-)) in pure water and 35 ‰ artificial seawater were examined by ion chromatography (IC). As packing materials of separation columns, 1-aminoundecyl group chemically bonded silica (AUS) gels were prepared. Separation of the anions in pure water was achieved using separation columns (150mm × 4.6mm i.d.) packed with the AUS gels, 0.1M NaCl + 5mM phosphate buffer (pH 4.5) as eluent, and a UV detector (wavelength 225nm). The anions in artificial seawater were separated and detected with a 300mm-long column without interferences by matrix anions such as chloride (Cl-) and sulfate (SO42-). The stationary phases have high-capacity anion-exchange/hydrophilic/hydrophobic interaction mixed-modes. The IC system was applied to five inorganic anions, IO3-, Br-, NO2-, NO3-, and I- in seawater of the Seto-Inland Sea, Japan. The detection limits (DLs, S/N = 3) were 11µgL-1 (IO3-), 93 (Br-), 1.3 (NO2-), 1.4 (NO3-), and 1.1 (I-) for a 100-µL sample injection.

Adaptive model predictive control scheme for partially internal thermally coupled air separation column

Partially Internal Thermally Coupled Air Separation Column (P-ITCASC) is a highly energy-efficient and cost-effective technology. However, its complex dynamics resulting from thermal coupling pose a challenge to the operating stability of this technology. This article, therefore, proposes an adaptive model predictive control (AMPC) scheme for the P-ITCASC process. The controller incorporates an auto-regressive and exogenous inputs (ARX) model, a linear time-varying Kalman filter, and a recursive polynomial model estimator (RPME) algorithm. Within RPME, ARX polynomial models are identified and utilized to estimate the time-varying parameters and update the prediction model of the process. The process states are observed through the Kalman filter, and the constrained receding horizon optimization problem is solved using quadratic programming. This control scheme ensures the closed-loop system's feasibility and stability in the presence of output/input constraints. An adaptive generic model control, model predictive control, and adaptive internal model control schemes were also designed for benchmarking study. Numerical simulations show that AMPC is more efficient in handling nonlinear dynamics and maintaining product concentration to desired set points compared to other control schemes.

Performance of structural insulation panels under eccentric axial and racking loads with varying opening ratios

Structural insulation panels, which are actively applied in the housing market in North America and Europe by utilizing wood, an eco-friendly material, as the main material, are composed of OSB (Oriented Strand Board), EPS (Expanded Polystyrene), and SPF (Spruce-Pine-Fir), which is used as a connection between the panels. Structural insulated panels are used as a load-bearing wall to resist external forces without installing separate columns. The production of structural insulation panels consists of applying adhesive to both sides of EPS, which acts as an insulation material, and pressing wood boards (OSB), which exert strength as a structural material. The OSB on the outside resists compressive and tensile forces, while the EPS on the inside resists shear forces. The joints and openings of the structural insulation panels are reinforced with SPF (Spruce-Pine-Fir) structural wood. When structural insulated panels are used as an exterior wall structure, the installation of openings is essential. Based on the opening size that is popularly used in wooden structures, the performance evaluation of structural insulation panels under eccentric axial load and repeated lateral load due to the reduction of the cross-sectional area by installing the opening was carried out, and the behavior analysis through variable analysis and comparison analysis with the design equation was carried out.

Effect of liquid elasticity on transient cavitation bubbles in the tube

We investigate the effect of liquid elasticity on the transient cavitation bubbles confined in a tube both experimentally and theoretically. In experiments, the tube-arrest apparatus is used to generate cavitation bubbles near the tube bottom with various polyethylene oxide solutions. Our experiments show that bubble dynamics, particularly the maximum bubble length, are significantly influenced by liquid elasticity. We establish a double oscillator model for the liquid column to explain the experimental results and predict the bubble dynamics over a broader range. Finally, we propose that the reciprocal of the cavitation number Ca2 and prR/k determine the regimes of the liquid column separation, where pr is the reference pressure, R is tube radius, and k is the “stiffness coefficient” of the liquid column. Our work provides a quantitative scaling of the dynamics of large cylindrical cavitation bubbles in viscoelastic liquids during the transient process.

Numerical modeling of cavity collapse water hammer in pipeline systems: Internal mechanisms and influential factors of transient flow and secondary pressure rise dynamics

This study explores the dynamics of pressure wave propagation and cavitation in pressurized pipelines during and after the rapid closure of the pipeline's end ball valve, utilizing a three-dimensional computational fluid dynamics approach with the method of characteristics, validated against Bergant and Simpson's experimental data of three degrees of cavitation. It innovatively examines transient pressure dynamics through both energy transformation and wave propagation perspectives, focusing on the phases of water column separation and coalescence, and the dynamics of flow interruption bubbles. The research delves into the detailed mechanisms of pressure wave propagation and further assesses the effects of physical factors. Key findings include: (1) As initial inlet velocities increase, cavitation starts earlier, extends further, and intensifies, with higher final volume fractions near the valve, indicating that higher velocities exacerbate cavitation. Higher inlet velocities also correlate with more intricate and expansive vortex formations. (2) Secondary pressure surges in water hammer result from the superposition of two-stage positive pressure waves. Initially, positive pressure waves within the conduit reflect twice from air pockets and the upstream boundary, remaining positive. Subsequently, they interact with secondary positive pressure waves reflected by the valve, causing a secondary pressure surge. (3) The fluid flow is laterally symmetry in the pipe cross section, except for minor local asymmetrical spikes in areas with vapor bubbles. Velocity discrepancies are notable near the pipe walls due to vapor accumulation, primarily on the upper wall due to buoyancy. This accumulation may narrow the flow area, possibly accelerating the water passing by. (4) Lower flow velocities, downward inclines, and slower valve closures diminish secondary pressure rise amplitudes in water hammer events, while reduced static heads intensify cavitation despite lessening pulse amplitudes. These findings offer valuable insights for the design and operational guidance of complex hydraulic systems during transient processes in urban water supplies.

Development of a HPLC system using a phase-separation multiphase flow as an eluent: an influence of column pressure on phase separation and chromatogram at room temperature.

We have developed a HPLC system where phase-separation multiphase flow works in the separation column as an eluent. We call the novel separation mechanism a phase-separation mode. The ternary mixed solution of water/acetonitrile/ethyl acetate, which is one of the two-phase-separation mixed solutions, caused the phase-separation multiphase flow via phase change from homogeneous to heterogeneous with the temperature effect (from 20 to 0°C). In this study, we tried to perform phase-separation multiphase flow with the pressure effect instead of the temperature one. The fused-silica capillary tube (50cm length and 50µm inner diameter) was allied to the downstream of the column to apply the pressure of 5.5MPa to the system. Model analytes of 2,6-naphthalenedisulfonic acid (2,6-NDS) and 1-naphthol (1-NA) were examined. For example, solutions (the volume% of water/acetonitrile/ethyl acetate; 20:55:25, organic-rich) and (60:30:10, water-rich) were used as eluent. The model analytes were not separated with both solutions at the pressure of 1.5MPa and 20°C. But with the organic-rich solution, 1-NA and 2,6-NDS were separated in this order and with the water-rich solution, they were separated in the reverse order at the pressure of 5.5MPa and 20°C. The phase-separation mode could be performed at the high pressure even at the room temperature.

An experimental and mechanism study on the pyrolysis of sulfur mustard

Experimental studies on the pyrolysis of sulfur mustard (HD) were conducted from 673 to 1473 K using Py-GC/MS combined with two separate columns. The HD pyrolysis rate exceeded 99 % at a pyrolysis time of approximately 2 seconds above 1073 K. The pyrolysis products of HD mainly include ethylene, vinyl chloride, carbon disulfide, thiophene, hydrogen chloride and hydrogen sulfide. The main reaction mechanism of HD pyrolysis was investigated using quantum chemistry methods combined with the TST/VTST theory. At 673 K, the initial reaction pathway of HD primarily involves an intramolecular HCl elimination and the cleavage of the C-S bond. The radical reactions will dominate the pyrolysis of HD once radical pool is formed. The reaction pathways of the important radical intermediates were analyzed, and the formation mechanisms of the main pyrolysis products were investigated. Theoretically, the high-pressure limit rate constants for the major reactions were calculated. This study contributes to a deeper understanding of the HD pyrolysis mechanism and provides a theoretical and data foundation for the destruction of HD.

Periodic Open Cellular Structures in Chemical Engineering: Application in Catalysis and Separation Processes.

Periodic open cellular structures (POCS) represent a promising new class of structured internals as next-generation catalyst supports in reactors or structured packing elements in separation columns. POCS feature a well-defined morphology and can be fabricated with high reproducibility even for complex geometries by means of additive manufacturing. This results in a uniform and easily controllable flow field, which allows for adjusting the heat and mass transport processes to realize optimal process conditions. We review the fundamentals of POCS, including design and manufacturing as well as transport phenomena for single- and multiphase systems. Moreover, we review recent POCS applications in reaction and separation processes and consider promising future application fields. The exceptional transport characteristics of POCS facilitate the design of highly efficient, flexible, resilient, and safe processes, which is key for achieving process intensification toward a sustainable future.

SMMP: A Deep-Coverage Marine Metaproteome Method for Microbial Community Analysis throughout the Water Column Using 1 L of Seawater.

Marine microbes drive pivotal transformations in planetary-scale elemental cycles and have crucial impacts on global biogeochemical processes. Metaproteomics is a powerful tool for assessing the metabolic diversity and function of marine microbes. However, hundreds of liters of seawater are required for normal metaproteomic analysis due to the sparsity of microbial populations in seawater, which poses a substantial challenge to the widespread application of marine metaproteomics, particularly for deep seawater. Herein, a sensitive marine metaproteomics workflow, named sensitive marine metaproteome analysis (SMMP), was developed by integrating polycarbonate filter-assisted microbial enrichment, solid-phase alkylation-based anti-interference sample preparation, and narrow-bore nanoLC column for trace peptide separation and characterization. The method provided more than 8500 proteins from 1 L of bathypelagic seawater samples, which covered diverse microorganisms and crucial functions, e.g., the detection of key enzymes associated with the Wood-Ljungdahl pathway. Then, we applied SMMP to investigate vertical variations in the metabolic expression patterns of marine microorganisms from the euphotic zone to the bathypelagic zone. Methane oxidation and carbon monoxide (CO) oxidation were active processes, especially in the bathypelagic zone, which provided a remarkable energy supply for the growth and proliferation of heterotrophic microorganisms. In addition, marker protein profiles detected related to ammonia transport, ammonia oxidation, and carbon fixation highlighted that Thaumarchaeota played a critical role in primary production based on the coupled carbon-nitrogen process, contributing to the storage of carbon and nitrogen in the bathypelagic regions. SMMP has low microbial input requirements and yields in-depth metaproteome analysis, making it a prospective approach for comprehensive marine metaproteomic investigations.

Development of LC-MS/MS method for quantification of Lurasidone using volumetric absorptive microsampling (VAMS); a comparative study between dried blood and plasma samples

The ecological impact of biological, chemical, and analytical research practices, including toxic reagents and biohazardous waste, has led to the development of alternative sampling and extraction techniques for bioanalysis. Microsampling (sample volume < 50 µL) aligns with the 3Rs principle, allowing multiple sampling points from the same animal at different time points and improving animal welfare. A bioanalytical method was developed to investigate factors related to bioanalytical challenges and the implementation of microsampling techniques. An LC-MS/MS method for Volumetric Absorptive Microsampling (VAMS), 20 µL, was developed for quantifying Lurasidone using a liquid–liquid extraction technique. The method uses a C18, Phenomenex column for chromatographic separation and a mobile phase composition of Methanol, Acetonitrile, and Water with 0.1 % HFBA. The method was validated over a concentration range of 5.0 to 1200.0 ng/mL and achieved acceptable precision and accuracy. The recovery for analyte from VAMS was approximately 40% at four different concentrations and is consistent (%CV < 15), with no significant differences among HCT levels. The matrix factor ranged between 85.00 and 115.00 %, showing no substantial issues with reduced or enhanced signal. The stability data showed no significant degradation of LUR in VAMS samples when stored at room temperature for 15 days. The newly established method for Lurasidone confirmed the use of VAMS sampling method and its analysis on LC-MS/MS. Further, the data obtained from microsampling techniques was compared with conventional (plasma) technique, as proof-of-concept, and it confirms the agreement between the two methods. The study supports the advantages of microsampling in protecting the environment and animals while maintaining scientific judgement.

Determination of Rare Earth Elements, Zirconium, Hafnium, Thorium and Uranium in Ultramafic Rocks by ICP‐MS after RE‐UTEVA Resin Columns for Separation and Pre‐Concentration

A simple method was developed for the determination of REEs, Zr, Hf, Th and U in ultramafic rocks by inductively coupled plasma‐mass spectrometry with a combination of RE and UTEVA extraction resins for their separation and pre‐concentration. Ultramafic rocks were digested with HNO3‐HF‐HClO4 and finally turned into 11 mol l−1 HCl solutions together with H3BO3 to remove insoluble fluorides. The removal of matrix elements was achieved during the loading procedure. Following this, REEs on RE resin, and Zr, Hf, Th and U on UTEVA resin were eluted with 10 ml of 0.24 mol l−1 HCl, with recoveries better than 94.4%. This method was validated using reference materials JP‐1, DTS‐2B, OKUM, UB‐N, MUH‐1 and DZΣ‐2, and the measurement results for target analytes were comparable to literature values, indicating its applicability to the determination of REEs, Zr, Hf, Th and U at ultra‐trace level in ultramafic rocks.

“It's going to get pretty tippy”: Stakeholder perspectives on the (dys)function of a four pillars drug strategy

A ‘drug strategy’ is a policy document that structures the priorities and directions for interventions for drug related issues within a particular jurisdiction and/or context. A ‘pillars’ drug strategy concentrates efforts through clustering separated columns of activity, such as law enforcement, harm reduction, treatment, and prevention. In this study, we examined drug policy stakeholders’ perspectives on the structure, function, and fit of a four pillar drug strategy framework in Vancouver, Canada. Utilizing qualitative interview data from fifteen drug policy stakeholders, we examine perspectives on Vancouver's four pillar drug strategy that was implemented over 20 years ago. Our findings are organized under three main themes: (1) the notion of ‘balance’ of efforts, resources, and attention across the pillars; (2) how the pillars function as a cohesive whole; (3) whether the pillars’ architecture is still fit-for-purpose. The architecture of four discrete pillars did not enable a sense of cohesion and collaboration of efforts, and instead elicited a sense of competition, conflict, fragmentation, simplicity, and rigidity of the strategy as a whole. These findings suggest that, in practice, a four pillars framework may be structurally dysfunctional in working towards a common goal. Our study questions the effectiveness of a commonly used 'pillars' framework and whether it needs to be reenvisaged.

Economic Optimization of Internal Thermally Coupled Air Separation Column Configurations

AbstractAn internal thermally coupled air separation column (ITCASC) process is an effective energy‐saving technology in the air separation process. However, a large economic investment is a crucial factor for the widespread use of this technology in practical applications. In this article, an alternative configuration design, namely, top‐integrated (T‐ITCASC), bottom‐integrated (B‐ITCASC), and top‐bottom‐integrated ITCASC (T‐B‐ITCASC) with a focus on energy savings and economic feasibility are studied. A rigorous optimization based on a nonlinear interior‐point algorithm was developed by integrating the dynamic model into the optimization formulation. In the context of ITCASC process design and optimization, numerical simulations demonstrated that T‐ITCASC, B‐ITCASC, and T‐B‐ITCASC configurations improved energy‐saving potential and reduced capital investment, compared to the F‐ITCASC and conventional air separation column (CASC) configurations. Among these optimized configurations, the T‐B‐ITCASC configuration is preferred.