Shell-like Xenon Nano-Traps within Angular Anion-Pillared Layered Porous Materials for Boosting Xe/Kr Separation.

Adsorptive separation of xenon (Xe) and krypton (Kr) is a promising technique but remains a daunting challenge since they are atomic gases without dipole or quadruple moments. Herein we report a strategy for fabricating angular anion-pillared materials featuring shell-like Xe nano-traps, which provide a cooperative effect conferred by the pore confinement and multiple specific interactions. The perfect permanent pore channel (4-5 Å) of Ni(4-DPDS)2 MO4 (M=Cr, Mo, W) can host Xe atoms efficiently even at ultra-low concentration (400 ppm Xe), showing the second-highest selectivity of 30.2 in Ni(4-DPDS)2 WO4 and excellent Xe adsorption capacity in Ni(4-DPDS)2 CrO4 (15.0 mmol kg-1 ). Crystallography studies and DFT-D calculations revealed the energy favorable binding sites and angular anions enable the synergism between optimal pore size and polar porosity for boosting Xe affinity. Dynamic breakthrough experiments demonstrated three MOFs as efficient adsorbents for Xe/Kr separation.

Enhanced self-assembly for the solubilization of cholesterol in molecular solvent/ionic liquid mixtures.

The development of new solvents combining greatly enhanced solubility for sparingly soluble compounds and good kinetic properties is challenging. In this study, we constructed a family of new molecular solvent/ionic liquid (IL) mixtures with amphiphilic, anionic functional long-chain carboxylate ionic liquids (LCC-ILs) as a key component for the solubilization of sparingly soluble compounds, using cholesterol as a model solute. Polarized optical microscopy (POM), wide angle X-ray diffraction (WAXD), Fourier-transform infrared (FTIR) spectra and 1H NMR showed that ordered mesoscopic structures, such as liquid crystals (LCs), were formed when cholesterol was dissolved in the mixtures, presenting a self-assembly induced dissolution mechanism driven by H-bond interaction and van der Waals forces in the mixtures. A synergistic effect between the molecular solvents and LCC-ILs was revealed, which contributed to enhanced solute-solvent self-assembly in dissolution over pure LCC-ILs and thus elevated solubility. Additionally, the effect of IL concentration, solvent type and anionic alkyl-chain length on self-assembly and solubility was investigated. These mixtures showed unparalleled solubilities for cholesterol, while maintaining a low viscosity. The quantitative solubilities (g g-1) of cholesterol were as high as 0.70, 0.84 and 0.82, respectively, at 25 °C in ethyl acetate/[P4444][C15H31COO] (50 wt%), n-heptane/[P4444][C15H31COO] (40 wt%) and ethyl acetate/[P4444][C17H35COO] (50 wt%) mixtures, which were the highest solubilities of cholesterol ever reported, six- to 980-fold higher than traditional molecular solvents and even one- to seven-fold higher compared to pure LCC-ILs. These results demonstrated the considerable potential of molecular solvent/LCC-ILs mixtures as promising solvents for solubilization and advanced separation processes.

Incorporation of N-Methyl-d-glucamine Functionalized Oligomer into MIL-101(Cr) for Highly Efficient Removal of Boric Acid from Water.

Polymeric resins are practically important adsorbents in a wide variety of applications, but they generally suffer from low surface areas and limited functionalized adsorption sites owing to their closely compacted and tangled polymeric chains. A metal-organic framework (MOF)-polymer composite with enhanced adsorption capacity against the compacted polymeric resins was reported. The strategy to incorporate functionalized oligomer within the cavities of the MOF was demonstrated by the preparation of MIL-101(Cr) incorporated with N-methyl-d-glucamine-based organosiloxane polymer. The resulting MOF composite shows high efficiency for the removal of boric acid from water because of exceptionally high loading of functional groups responsible for the boron adsorption. This material offers promising perspectives for boron removal applications in seawater desalination.

Nonaqueous lyotropic ionic liquid crystals: preparation, characterization, and application in extraction.

A class of new ionic liquid (IL)-based nonaqueous lyotropic liquid crystals (LLCs) and the development of an efficient IL extraction process based on LC chemistry are reported. The nonaqueous LLCs feature extraordinarily high extraction capacity, excellent separation selectivity, easy recovery, and biocompatibility. This work also demonstrates that the introduction of self-assembled anisotropic nanostructures into an IL system is an efficient way to overcome the intrinsically strong polarity of ILs and enhances the molecular recognition ability of ILs. The distribution coefficients of IL-based LLCs for organic compounds with H-bond donors reached unprecedented values of 50-60 at very high feed concentrations (>100 mg mL(-1) ), which are 800-1000 times greater than those of common ILs as well as traditional organic and polymer extractants. The IL-based nonaqueous LLCs combining the unique properties of ILs and LCs open a new avenue for the development of high-performance extraction methods.

Optimizing Trace Acetylene Removal from Acetylene/Ethylene Mixture in a Flexible Metal-Organic Framework by Crystal Downsizing.

Improving the gas separation performance of metal-organic frameworks (MOFs) by crystal downsizing is an important but often overlooked issue. Here, we report three different-sized flexible ZUL-520 MOFs (according to the crystal size from large to small, the three samples are, respectively, named ZUL-520-0, ZUL-520-1, and ZUL-520-2) with the same chemical structure for optimizing trace acetylene (C2H2) removal from acetylene/ethylene (C2H2/C2H4) mixture. The three differently sized activated ZUL-520 (denoted as ZUL-520a) exhibited almost identical C2H2 uptake of 4.8 mmol/g at 100 kPa, while the C2H2 uptake at 1 kPa increased with a downsizing crystal. The C2H2 uptake of activated ZUL-520-2 (denoted as ZUL-520-2a) at 1 kPa was ∼55% higher than that of activated ZUL-520-0 (denoted as ZUL-520-0a). The adsorption isotherms and adsorption kinetics validated that gas adsorptive separation is governed not only by adsorption thermodynamics but also by adsorption kinetics. In addition, all three different-sized ZUL-520a MOFs showed high C2H2/C2H4 selectivity. Grand canonical Monte Carlo (GCMC) simulations and dispersion-corrected density functional theory (DFT-D) computations illustrated a plausible mechanism of C2H2 adsorption in MOFs. Importantly, breakthrough experiments demonstrated that ZUL-520a can effectively separate the C2H2/C2H4 (1/99, v/v) mixture and the C2H4 productivity obtained by ZUL-520-2a was much higher than that by ZUL-520-0a. Our work may provide an easy but powerful strategy for upgrading the performance of gas adsorptive separation in MOFs.

Enantiomeric separation of citalopram base by supercritical fluid chromatography.

The chiral separation of citalopram base by supercritical fluid chromatography on a semipreparative Chiralpak AD column was studied with the use of three alcohol-type modifiers (methanol, ethanol, and 2-propanol) with different volume percentages (5, 10, and 15%). The best separation was achieved when 10% 2-propanol was used in the presence of 0.1% diethylamine as additive. Under these conditions, the resolution reached 2.15 and the selectivity was 1.388. In addition, other parameters that affected the retention and separation properties, i.e. temperature, pressure, and density, were studied in detail. At the same pressure, a decrease in the temperature improved the enantioselectivity as the experimental temperature range was below the isoelution temperature. However, the temperature dependence of the retention factor was complicated. As a rule, the retention factor decreased when the temperature increased at the same density. A satisfactory regression of the logarithm of the retention factor versus density and temperature was obtained using a simplified lattice-fluid model. Surprisingly, the relationship between the Henry constant and density can be accurately correlated by using the same quadratic equation.

Supramolecular Assembly of One-Dimensional Coordination Polymers for Efficient Separation of Xenon and Krypton.

Efficient separation and purification of xenon (Xe) from krypton (Kr) represent an industrially crucial but challenging process. While the adsorption-based separation of these atomic gases represents an energy-efficient process, achieving highly selective adsorbents remains a difficult task. Here, we demonstrate a supramolecular assembly of coordination polymers, termed as M(II)-dhbq (M = Mg, Mn, Co, and Zn; dhbq = 2,5-dihydroxy-1,4-benzoquinone), with high-density open metal sites (5.3 nm-3) and optimal pore size (5.5 Å), which are able to selectively capture Xe among other chemically inert gases including Kr, Ar, N2, and O2. Among M(II)-dhbq materials, Mn-dhbq exhibits the highest Xe uptake capacity of 3.1 mmol/g and a Xe/Kr selectivity of 11.2 at 298 K and 1.0 bar, outperforming many state-of-the-art adsorbents reported so far. Remarkably, the adsorption selectivity of Mn-dhbq for Xe/O2, Xe/N2, and Xe/Ar at ambient conditions reaches as high as 70.0, 139.3, and 64.0, respectively. Direct breakthrough experiments further confirm that all M(II)-dhbq materials can efficiently discriminate Xe atoms from other inert gases. It is revealed from the density functional theory calculations that the strong affinity between Xe and the coordination polymer is mainly attributed to the polarization by open metal sites.

Mathematical modeling of the impact of actin and keratin filaments on keratinocyte cell spreading.

Keratin intermediate filaments (IFs) form cross-linked arrays to fulfill their structural support function in epithelial cells and tissues subjected to external stress. How the cross-linking of keratin IFs impacts the morphology and differentiation of keratinocytes in the epidermis and related surface epithelia remains an open question. Experimental measurements have established that keratinocyte spreading area is inversely correlated to the extent of keratin IF bundling in two-dimensional culture. In an effort to quantitatively explain this relationship, we developed a mathematical model in which isotropic cell spreading is considered as a first approximation. Relevant physical properties such as actin protrusion, adhesion events, and the corresponding response of lamellum formation at the cell periphery are included in this model. Through optimization with experimental data that relate time-dependent changes in keratinocyte surface area during spreading, our simulation results confirm the notion that the organization and mechanical properties of cross-linked keratin filaments affect cell spreading; in addition, our results provide details of the kinetics of this effect. These in silico findings provide further support for the notion that differentiation-related changes in the density and intracellular organization of keratin IFs affect tissue architecture in epidermis and related stratified epithelia.

Accurate measurements of infinite dilution activity coefficients using gas chromatography with static-wall-coated open-tubular columns.

Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (γ(∞)) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n(2)) in WCOT columns raise large errors. By rationally revising the γ(∞)-calculation equation for static-wall-coated open-tubular column, we observed that U and n(2) are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate γ(∞) determination. In this study, we validate our revised γ(∞)-calculation equation by measuring γ(∞) in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their γ(∞) values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common γ(∞)-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined γ(∞) values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches.

Increased endothelial exocytosis and generation of endothelin-1 contributes to constriction of aged arteries.

RATIONALE: Circulating levels of endothelin (ET)-1 and endogenous ET(A)-mediated constriction are increased in human aging. The mechanisms responsible are not known. OBJECTIVE: Investigate the storage, release, and activity of ET-1 system in arteries from young and aged Fischer-344 rats. METHODS AND RESULTS: After NO synthase inhibition (L-NAME), thrombin contracted aged arteries, which was inhibited by endothelial denudation, ET(A) receptor antagonism (BQ123), and ECE inhibition (phosphoramidon, SM19712) or by inhibiting exocytosis (TAT-NSF, N-ethylmaleimide-sensitive factor inhibitor). Thrombin did not cause endothelium-dependent contraction of young arteries. In aged but not young arteries, thrombin rapidly increased ET-1 release, which was abolished by endothelium denudation or TAT-NSF. L-NAME did not affect ET-1 release. ET-1 immunofluorescent staining was punctate and distinct from von Willebrand factor (VWF). VWF and ET-1 immunofluorescent intensity was similar in young and aged quiescent arteries. Thrombin rapidly increased ET-1 staining and decreased VWF staining in aged but had no effect in young aortas. After L-NAME, thrombin decreased VWF staining in young aortas. NO donor DEA-NONOate (1 to 100 nmol/L) reversed thrombin-induced exocytosis in young (VWF) but not aged L-NAME-treated aortas (VWF, ET-1). Expression of preproET-1 mRNA and ECE-1 mRNA were increased in aged compared to young endothelium. BigET-1 levels and contraction to exogenous BigET-1 (but not ET-1) were also increased in aged compared to young arteries. CONCLUSIONS: The stimulated exocytotic release of ET-1 is dramatically increased in aged endothelium. This reflects increased reactivity of exocytosis, increased expression and storage of ET-1 precursor peptides, and increased expression of ECE-1. Altered endothelial exocytosis of ET-1 and other mediators may contribute to cardiovascular pathology in aging.

Cyclic stretch stimulates vascular smooth muscle cell alignment by redox-dependent activation of Notch3.

Mice deficient in Notch3 have defects in arterial vascular smooth muscle cell (VSMC) mechanosensitivity, including impaired myogenic responses and autoregulation, and inappropriate VMSC orientation. Experiments were performed to determine if Notch3 is activated by mechanical stimulation and contributes to mechanosensitive responses of VSMCs, including cell realignment. Cyclic, uniaxial stretch (10%, 1 Hz) of human VSMCs caused Notch3 activation, demonstrated by a stretch-induced increase in hairy and enhancer of split 1/hairy-related transcription factor-1 expression, translocation of Notch3 to the nucleus, and a decrease in the Notch3 extracellular domain. These effects were prevented by inhibiting the expression [small interfering (si)RNA] or proteolytic activation of Notch3 {N-(R)-[2-(hydroxyaminocarbonyl)methyl]-4-methylpentanoyl-l-naphthylalanyl-l-alanine-2-aminoethyl amide (TAPI-1; 50 µmol/l) to inhibit TNF-α-converting enzyme (TACE) or N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester (DAPT; 20 µmol/l) to inhibit γ-secretase}. Stretch increased the activity of ROS within VSMCs, determined using dichlorodihydrofluorescein fluorescence. Catalase (1,200 U/ml), which degrades H2O2, inhibited the stretch-induced activation of Notch3, whereas in nonstretched cells, increasing H2O2 activity [H2O2 or manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin] caused activation of Notch3. Stretch increased the activity of TACE, which was prevented by catalase. Stretch-induced activation of p38 MAPK in VSMCs was inhibited either by catalase or by inhibiting Notch3 expression (siRNA). Stretch caused VSMCs to realign perpendicular to the direction of the mechanical stimulus, which was significantly inhibited by catalase or by inhibiting the expression (siRNA) or activation of Notch3 (TAPI-1 or DAPT). Therefore, cyclic uniaxial stretch activates Notch3 signaling through a ROS-mediated mechanism, and the presence of Notch3 is necessary for proper stretch-induced cell alignment in VSMCs. This mechanism may contribute to the physiological role of Notch3 in mediating developmental maturation of VSMCs.

Enantioseparation of racemic paroxol on an amylose-based chiral stationary phase by supercritical fluid chromatography.

The separation of racemic paroxol, a key precursor of trans-(-)-paroxetine, on Chiralpak AD-H, an amylose-based chiral stationary phase, by supercritical fluid chromatography was studied. Pulse experiments were investigated using supercritical carbon dioxide modified with methanol (MeOH), ethanol and 2-propanol at 35°C and 15 MPa. Retention and separation factors were determined under analytical conditions for different mobile phase compositions. Among the modifiers used, MeOH was shown to be the best additive, and 5% v/v of MeOH was the preferable concentration at which selectivity of 1.14 and resolution of 3.0 was obtained. In order to evaluate the potential with respect to preparative separations, the adsorption isotherms of individual enantiomers of paroxol were estimated using the elution by characteristic point method. Isotherm parameters were determined from the overloaded elution profiles that were collected at pressure ranging from 15 to 24 MPa. The isotherms obtained were further validated by comparing experimentally recorded elution profiles with the predictions based on the equilibrium-dispersive model. The results are important to the process design and optimization of preparative supercritical fluid chromatography application.

Microgeometry-independent equation for measuring infinite dilution activity coefficients using gas-liquid chromatography with static-wall-coated open-tubular columns.

Gas-liquid chromatography is an effective method to determine infinite dilution activity coefficients (γ∞). Wall-coated open-tubular (WCOT) column which offers more advantages over packed column should be a preferable column type; however, the small carrier gas flow rate and stationary phase amount in WCOT columns limit its application in the determination of γ∞. Mathematical strategy made some progress to avoid the quantification problem in the determination of γ∞ by static-wall-coated open-tubular (SWCOT) columns. However, the previously reported strategy was based on the assumption that SWCOT column was geometrically an ideal hollow cylinder, which indeed deviates from the reality. In this study, without that assumption, we derived a new microgeometry-independent equation by using the relationship between the hold-up volume (VM) and the volume of stationary phase (VL), and used it to measure the γ∞ of various organic solutes in two ionic liquids (ILs) 1­butyl­3-methylimidazolium dicyanamide and 1,3-dibutyronitrile-imidazolium bis((trifluoromethyl)sulfonyl)imide, both of which contain double cyano groups in the anion or cation. Phase loading study was adopted to eliminate the influence of interfacial adsorption to partition. The infinite dilution partial molar excess enthalpy, selectivity and capacity were directly calculated from the experimental γ∞ values, and the linear solvation energy relationship (LSER) model was used to characterize the specific properties of both ILs. This new established equation will promote the application of SWCOT columns in thermodynamic measurement and benefit the fast screening of novel solvents for chemical separation processes.

Highly efficient treatment of textile dyeing sludge by CO2 thermal plasma gasification.

Textile dyeing sludge is complex hazardous material with increasing amount year by year, and the conventional treatment techniques are limited by many drawbacks such as water/soil contamination, incomplete degradation of hazardous organics or inefficient fixation of toxic heavy metals. This work reported the first example of thermal plasma gasification treatment of textile dyeing sludge in a homemade rotating arc plasma reactor, which not only significantly reduced the volume and eliminated the safety risk of textile dyeing sludge, but also produced valuable syngas that can be used for chemical industry. At a feed rate of 36 g/min and a CO2 flow rate of 0.43 Nm3/h (14.08 g/min), the carbon conversion efficiency of gasification was 99.9%; and the energy conversion efficiency could reach 71.8%; and the lower heating value of syngas-rich produced gas was 8.91 MJ/Nm3. At the same time, the volume reduction ratio of sludge was 41.19% and the fixing efficiency of the heavy metals in solid products reached above 99%. Toxicity characteristic leaching procedure confirmed the solid products were harmless in a wide environmental pH range. The proposed method exhibits its great potential of simultaneously realizing harmless, minimization and reclamation of textile dyeing sludge and even other hazardous solid waste.

Inverse Adsorption Separation of CO2/C2H2 Mixture in Cyclodextrin-Based Metal-Organic Frameworks.

The demand for CO2/C2H2 separation, especially the removal of CO2 impurity, continues to grow because of the high-purity C2H2 required for various industrial applications. The adsorption separation of C2H2 and CO2 via porous materials is gaining a considerable attention as it is more energy-efficient compared with cryogenic distillation. The ideal porous materials are those that preferentially adsorb CO2 over C2H2; however, very few adsorbents meet such requirement. Herein, two isostructural cyclodextrin-based CD-MOFs (CD-MOF-1 and CD-MOF-2) were demonstrated to have an inverse ability to selectively capture CO2 from C2H2 by single-component adsorption isotherms and dynamic breakthrough experiments. These two MOFs showed excellent adsorption capacity and benchmark selectivity (118.7) for CO2/C2H2 mixture at room temperature, enabling the pure C2H2 to be obtained in only one step. This work revealed that these materials were promising adsorbents for obtaining high-purity C2H2 via selectively capturing CO2 from C2H2.

Engineering the Pore Size of Pillared-Layer Coordination Polymers Enables Highly Efficient Adsorption Separation of Acetylene from Ethylene.

The pore size of adsorbents plays a vital role in determining the overall separation performance of gas separation and purification by adsorption. In this work, the pore apertures of the coordination pillared layer (CPL) was systematically controlled by adjusting the length of pillared ligands. We used pyrazine, 4,4'-bipyridine, and 1,2-di(4-pyridyl)-ethylene with increased length to synthesize CPL-1 (L = pyrazine), CPL-2 (L = 4,4'-bipyridine), and CPL-5 [L = 1,2-di(4-pyridyl)-ethylene], respectively. The aperture size of these CPLs varies from 4 to 11 Å: CPL-1 (4 × 6 Å2), CPL-2 (9 × 6 Å2), and CPL-5 (11 × 6 Å2). Among the three frameworks, CPL-2 exhibits the highest C2H2 uptake at ambient conditions as it has moderate pore size and porosity. However, CPL-1 has the best separation performance in the breakthrough experiments with binary gas mixture of C2H2/C2H4, thanks to the optimal pore size nearly excluding C2H4, which is only observed in the state-of-the-art UTSA-300a so far. The DFT calculations were carried out to elucidate the specific adsorption sites for both acetylene and ethylene among these frameworks. The modeling results suggest that binding strength is highly related to aperture size and that CPL-1 shows the highest adsorption selectivity owing to the optimal pore size. This work demonstrates that engineering pore size enables us to fabricate the highly efficient metal-organic framework (MOF)-based adsorbents for specific gas separation on the basis of the isoreticular chemistry.

Cloning and functional analysis of the swine eNOS promoter.

We have cloned the swine eNOS promoter and analyzed its function in newborn swine pulmonary artery endothelial cells (PAECs). Analysis of the 2.1 kb 5' flanking region revealed that the swine eNOS promoter is, like its counterparts in human and other species, a TATA-less promoter. The transcription start site, determined by 5' RLM-RACE, was located 62 bp upstream of the translation start codon. Promoter activity was demonstrated by transient transfection of 5' deletion promoter/luciferase constructs into swine PAECs, and indicated that the proximal region from -227 to -82 was necessary for basal promoter activity. Positive cis-regulatory elements were present from -227 to -1290, while negative cis-regulatory elements may be present from -1290 to -1926 bp. Electrophoretic mobility shift assay (EMSA) of the proximal region demonstrated that multiprotein complexes were formed in the conserved proximal region of the swine eNOS promoter and a novel Spl site at -68/-59 was involved in the formation of these complexes.

Determination of soyasaponins Ba and Bb in human serum by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS-MS) has been developed and validated for the determination of soyasaponins Ba and Bb in human serum using glycyrrhizin as internal standard (I.S.). Soyasaponins Ba and Bb were extracted from human serum by liquid-liquid extraction and cleaned up by C(18) solid-phase extraction (SPE), followed by separation on a C(18) reversed-phase column using acetonitrile/water containing 0.025% acetic acid as a mobile phase for gradient elution. Soyasaponins Ba and Bb, and I.S. were ionized by negative ion pneumatically assisted electrospray and detected by HPLC-MS-MS in the multiple-reaction monitoring (MRM) mode using precursor-->product ion combinations at m/z 958-->940, 942-->924 and 822-->351, respectively. The calibration curves were linear (r(2)>0.991) in the concentration range of 0.5-100.0 ng/mL, with lower limits of quantification of 0.5 and 0.3 ng/mL for soyasaponins Ba and Bb, respectively, in human serum. Intra-day and inter-day relative standard deviations (R.S.D.) were less than 7.9 and 11.3%, respectively. The mean recoveries of soyasaponins Ba and Bb ranged from 92 to 101% and from 85 to 94%, respectively.

Hybrid Deep Eutectic Solvents with Flexible Hydrogen-Bonded Supramolecular Networks for Highly Efficient Uptake of NH3.

Serious environmental concerns have led to a great demand for efficient uptake of NH3 by solvents. However, traditional aqueous absorbents have many shortcomings and efforts to use ionic liquids have met with limited success. A hybrid deep eutectic solvents (DESs) designed with a flexible hydrogen-bonded supramolecular network exhibits both exceptional NH3 uptake capacity and superior desorption-regeneration performance, along with superb NH3 /CO2 selectivity and environmental merit. Elucidated by molecular dynamic simulations and spectroscopic analysis, the abundant hydrogen-bonding sites in the hybrid DESs bind every atom of the NH3 molecule and enable strong physical reversible solvation, whereas the multiple interactions among the hybrid components create a flexible hydrogen-bonded supramolecular network and allow for solvent-unbreaking absorption to ensure the full participation of the solvent and process stability. A mass solubility of NH3 up to 0.13 g g-1 was achieved at 313 K and 101 kPa by the hybrid DES choline chloride/resorcinol/glycerol (1:3:5), which is higher than all reported ionic liquids and ordinary DESs. Moreover, the performance remained the same after ten absorption-desorption cycles and the DESs could be easily regenerated.

Rapid quantification and characterization of soyasaponins by high-performance liquid chromatography coupled with electrospray mass spectrometry.

A method using high-performance liquid chromatography (HPLC) with electrospray ionization mass spectrometry (ESI-MS) in the negative mode is presented for the quantification and characterization of different soyasaponins using six authentic soyasaponin standards. This method was successfully applied to the rapid separation of diverse soyasaponins, more than 50, including soyasaponins A in different degrees of acetylation, and soyasaponins B in both their 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated and non-conjugated forms in different samples in one single run for only 30 min. Standard calibration curve was linear over the concentration range of 0.010-1.0 mg/L for each soyasaponin. Within-day and day-to-day relative standard deviations were less than 9.2 and 13.1%, respectively.