Developing oxaliplatin and IL-15 Co-carried gels as drug depots to enable triple-interlocked combination therapy for colorectal cancer.

Chemo-immunotherapy, which involves the simultaneous use of chemotherapy drug and immunotherapeutic agent to achieve synergistic effects, plays a crucial role in cancer treatment. However, the immunosuppressive microenvironment, insufficient tumor specificity, and serious systemic side effects hinder their synergistic therapeutic effects and clinical applications. Herein, T cell and natural killer (NK) cell, which are the most important immune effector cells, were both activated to reverse the immunosuppressive microenvironment. To simplify drug carriers, oxaliplatin was selected as the chemotherapy drug which can both induce the ICD effect and activate T cells. IL-15 was selected to activate NK cells. To enhance the productivity of the carrier and reduce side effects, the easy-prepared thermosensitive hydrogel (OXL/IL-15 TG) was developed to co-load oxaliplatin-loaded liposomes (OXL) and IL-15. Colorectal cancer, suitable for in situ administration, was selected as model cancer. The resulting novel triple-interlocked combination therapy could directly kill the tumor cells, induces ICD effect and activate NK cells. After administration, OXL/IL-15 TG was formed serving as a drug depot, slowing releasing OXL and IL-15 non-interferencely. OXL around 165.47±7.04 nm was passively delivered to tumor tissue, killing tumor cells and inducing ICD effect. The results demonstrated that IL-15 stimulated the activation of NK cells. In tumor-bearing mice models, OXL/IL-15 TG exhibited a remarkable and noteworthy anti-tumor efficacy, and expanded survival rate. Notably, OXL/IL-15 TG led to an enhanced infiltration of CD3+CD8+ T cells and CD3-CD49+ NK cells within the tumor tissue. Overall, the triple-interlocked combination therapy provided a new idea for colorectal cancer therapy.

Safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat: A randomized, double-blind, placebo-controlled single- and multiple-dose escalation study in Chinese healthy subjects.

BACKGROUND AND OBJECTIVE: Neutrophil elastase has been identified as a potential therapeutic target for acute lung injury or acute respiratory distress syndrome, and Sivelestat is a selective, reversible and competitive neutrophil elastase inhibitor. This study was designed to investigate the safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat in healthy Chinese subjects. METHODS: A randomized, double-blind, placebo-controlled single- and multiple-dose escalation clinical trial was carried out. Briefly, healthy volunteers in twelve cohorts with 8 per cohort received 1.0-20.2 mg/kg/h Sivelestat or placebo in an intravenous infusion manner for two hours, and healthy volunteers in four cohorts received two hours intravenous infusion of 2.0-5.0 mg/kg/h Sivelestat or placebo with an interval of twelve hours for seven times. The safety and tolerability were evaluated and serial blood samples were collected for pharmacokinetics and neutrophil elastase inhibitory effects analysis at the specified time-point. RESULTS: A total of 128 subjects were enrolled and all participants completed the study except one. Sivelestat exhibited satisfactory safety and tolerability up to 20.2 mg/kg/h in single-dose cohorts and 5.0 mg/kg/h in multiple-dose cohorts. Even so, more attention should be paid to the safety risks when using high doses. The Cmax and AUC of Sivelestat increased in a dose dependent manner, and Tmax was similar for different dose cohorts. In multiple-dose cohorts, the plasma concentrations reached steady state 48 h after first administration and the accumulation of Cmax and AUC was not obvious. Furthermore, the Cmin_ss of 5.0 mg/kg/h dose cohort could meet the needs of clinical treatment. For some reason, the pharmacodynamics data revealed that the inhibitory effect of Sivelestat on neutrophil elastase content in healthy subjects was inconclusive. CONCLUSION: Sivelestat was safe and well tolerated with appropriate pharmacokinetic parameters, which provided support for more diverse dosing regimen in clinical application. CLINICAL TRIAL REGISTRATION: www.chinadrugtrials.org.cn identifier is CTR20210072.

Itaconic Acid-Based Organic-Polymer Monolithic Column for Hydrophilic Capillary Electrochromatography and Its Application in Pharmaceutical Analysis.

Itaconic acid is an excellent hydrophilic monomer owing to the dicarboxylic group possessing strong polarity. This study reports on the preparation of a new organic-polymer monolithic column poly(itaconic acid-co-3-(acryloyloxy)-2-hydroxypropyl methacrylate) (poly(IA-co-AHM)) featuring excellent hydrophilic chromatography ability and its application in pharmaceutical analysis. The monolithic column was successfully synthesized by using the monomer itaconic acid and the cross-linker AHM through an in situ copolymerization method. Optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were employed for the characterization of the poly(IA-co-AHM) monolithic column, and all of these demonstrated that the prepared itaconic acid-based monolithic column exhibited satisfactory permeability and a homogeneous porous structure. Owing to the carboxylic groups of itaconic acid, a cathodic electroosmotic flow (EOF) was generated on the itaconic acid-based monolithic column among the pH ranges of the mobile phase from 4.0 to 9.0. Depending on the powerful hydrophilic interactions, different kinds of polar substances, including thioureas, nucleoside drugs, sulfonamides, and polypeptides, were separated efficiently by the itaconic acid-based monoliths poly(IA-co-AHM). The separations of polar compounds were successfully realized, even at a lower level of 50% acetonitrile content on this monolithic column. The highest column efficiencies corresponding to N,N'-dimethylthiourea and idoxuridine were 102 720 and 124 267 N/m, respectively. The poly(IA-co-AHM) monolithic column displayed excellent repeatability, whose relative standard deviations (RSDs) of the retention time and peak area were both lower than 5.0%. All experimental results demonstrated that the new itaconic acid-functionalized monolithic column was greatly appropriate to separate the polar compounds under the HILIC mode.

Driving natural killer cell-based cancer immunotherapy for cancer treatment: An arduous journey to promising ground.

Immunotherapy represents one of the most effective strategies for cancer treatment. Recently, progress has been made in using natural killer (NK) cells for cancer therapy. NK cells can directly kill tumor cells without pre-sensitization and thus show promise in clinical applications, distinct from the use of T cells. Whereas, research and development on NK cell-based immunotherapy is still in its infancy, and enhancing the therapeutic effects of NK cells remains a key problem to be solved. An incompletely understanding of the mechanisms of action of NK cells, immune resistance in the tumor microenvironment, and obstacles associated with the delivery of therapeutic agents in vivo, represent three mountains that need to be scaled. Here, we firstly describe the mechanisms underlying the development, activity, and maturation of NK cells, and the formation of NK­cell immunological synapses. Secondly, we discuss strategies for NK cell-based immunotherapy strategies, including adoptive transfer of NK cell therapy and treatment with cytokines, monoclonal antibodies, and immune checkpoint inhibitors targeting NK cells. Finally, we review the use of nanotechnology to overcome immune resistance, including enhancing the anti-tumor efficiency of chimeric antigen receptor-NK, cytokines and immunosuppressive-pathways inhibitors, promoting NK cell homing and developing NK cell-based nano-engagers.

Benzoic acid-modified monolithic column for separation of hydrophilic compounds by capillary electrochromatography with high content of water in mobile phase.

Hydrophilic column combined with mobile phase containing high content of water is a green method for the separation of polar compounds, but there are few related studies, and the separation efficiency and performance of existing columns still needs to be improved. In this work, a novel monolithic column for separation of hydrophilic compounds under both high water content and HILIC condition, was prepared by in-situ polymerization using 4-vinylbenzoic acid (VBA) and 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol (AMAP) as functional monomers. The poly(VBA-co-AMAP) monolithic column showed good separation performance towards various polar compounds under different chromatographic conditions based on the π-interaction, hydrophobic and hydrogen bonding interactions provided by 4-vinylbenzoic acid functional monomer. The highest column efficiency for adenine was over 2.15 × 105 plates m-1 (theoretical plate, N). In addition, the monolith showed good stability and reproducibility, the relative standard deviations (RSDs) of retention times within days (n = 5), between days (n = 5), between columns (n = 3) and between batches (n = 3) were 0.47-1.13%, 1.20-2.68%, 0.59-1.78% and 1.54-3.60%, respectively. This novel type of monolith has great application potential in the separation of hydrophilic compounds.

Glycine-modified organic polymer monolith featuring zwitterionic functionalities for hydrophilic capillary electrochromatography.

Allylglycine, a conventional amino acid derivative, possesses typical zwitterionic and hydrophilic functionalities deriving from the carboxyl and amino groups in its structure. A novel monolithic column poly(allylglycine-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (AGly-co-TAT) with powerful hydrophilic selectivity and obvious zwitterionic feature was synthesized successfully with the monomer allyglycine and the cross-linker 1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine through in-situ copolymerization for capillary electrochromatography. The obtained monolithic column has good permeability. Due to the zwitterionic functional groups of allylglycine, the poly(AGly-co-TAT) monolithic column can generate a cathodic and anodic electroosmotic flow (EOF) by changing the mobile phase pH, which is beneficial to expand its application range. The separations of different series of polar analytes, thioureas, xanthines, phenols, peptides and acidic compounds are achieved on this hydrophilic monolithic column due to the powerful hydrophilic, electrostatic and hydrogen bond interactions. Using this monolithic column, hydrophilic separations are achieved even at a lower level of 50% organic solvent. The separation efficiency up to 1.41 × 105 N m-1 and 1.19 × 105 N m-1 is achieved for the separation of theophylline and phenol, respectively. For a real sample, cytochrome C digestion, the monolithic column shows good separation performance, which offers the potential application of the monolithic column on proteomics study.

γ-Cyclodextrin metal-organic framework supported by polydopamine as stationary phases for electrochromatographic enantioseparation.

Metal-organic frameworks (MOFs) are a novel class of porous nanomaterials composed of metals and organic linkers that have been used in many fields. A novel stereoselective stationary phase for capillary electrochromatography (CEC) has been developed in this work by employing a biodegradable, easier-to-prepare and green homochiral MOFs (Cu-SD), which composed of octakis-[6-deoxy-6-(3-mercaptopropanoic sodium)]-γ-cyclodextrin (SD, sugammadex) and transition metal ion (Cu2+) supported by polydopamine as linker. The modified capillary was characterized by scanning electron microscopy (SEM), X-ray spectrometry (XRD), energy dispersive (EDS) and Fourier transform infrared spectroscopy (FT-IR). The Cu-SD modified capillary column exhibited outstanding chiral recognition separation for five Dns-DL-amino acids (the DL-forms of phenylalanine, leucine, valine, threonine, serine). In addition, the modified column showed excellent stability and reproducibility. The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) and between columns (n = 3) enantioseparations were less than 0.27, 1.45 and 4.88%, respectively. Conceivably, this new-type of γ-CD-MOF represents a useful chiral stationary phase in electrochromatographic separations, and it has great potential in chiral separation field.

Fluoro-functionalized stationary phases for electrochromatographic separation of organic fluorides.

Fluorous affinity means remarkably specific interaction between highly organic fluorides. This work aims to explore the potential of fluoro-functionalized stationary phase for the separation of organic fluorides by means of fluorous-fluorous interaction. Here, by using the Michael addition strategy between 1H,1H,2H,2H-perfluorodecanethiol (PFDT) and polydopamine (PD), a novel fluoro-functionalized stationary phase was synthesized for open-tubular capillary electrochromatography (OT-CEC). The PFDT@PD was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray Photoelectron Spectrometer (XPS). The PFDT@PD@capillary exhibited outstanding separation performance towards neutral compounds (such as alkylbenzenes and chlorobenzenes) and organic fluorides (such as fluorobenzenes and perfluoroalkyl methacrylates etc.) with high resolution and high separation efficiency by hydrophobic interaction and fluorous-fluorous interaction. In addition, the column shows good stability and reproducibility. The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) runs and between columns (n = 3) are less than 0.39%, 1.22% and 3.87%, respectively. This novel type of fluoro-functionalized stationary phase represents a great application potential in organic fluorides separation field.

Strong hydrophilic monolithic column functionalized with amphiphilic benzyl quinine for capillary electrochromatography and application in pharmaceutical analysis.

An innovative strong hydrophilic organic polymer monolithic column of poly(N-benzylquininium chloride-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (poly(NBQ-co-TAT)) has been successfully synthesized through in situ copolymerization for capillary electrochromatography. The amphiphilic monomer NBQ and the strong polar cross-linker TAT are firstly used in hydrophilic electrochromatography by taking advantage of the exhibition of hydrophilicity at lower levels of organic solvent and ease formation of porous structure. The monolithic column poly(NBQ-co-TAT) shows powerful hydrophilic selectivity with mobile phase containing more than 60% organic solvent. The introduction of NBQ and TAT enlarges the sources of functional monomers and cross-linkers for HILIC. Due to the presence of the positively charged group in NBQ, an anodic electroosmotic flow is generated with the change of pH values from 2.0 to 12.0. The monolithic column was used for the separations of thioureas, phenols, xanthines, nucleobases, acidic substances and pharmaceuticals. The highest column efficiency for N, N'-dimethylthiourea is 1.15 × 105 N m-1. The application of the monolithic column for a real sample, cytochrome C digestion indicates its great potential in practical application.

Ionic liquid-copolymerized monolith based porous layer open tubular column for CEC-MS analysis.

Developing novel capillary electrochromatography (CEC) column with high separation efficiency and capacity is an essential work in CEC. In this work, porous layer open tubular (PLOT) column has been developed by co-polymerization of quaternary ammonium typed ionic liquid (IL), 1-allyl-methylimidazolium chloride (AlMeIm+Cl-) with styrene (IL-styrene) and ethylene dimethacrylate (EDMA) for CEC-MS analysis. The PLOT-CEC column possesses high separation efficiency and capacity while keeping the inherent advantages of open tubular (OT) column unaltered, which is suitable for CEC analysis. Due to the uniform branch-like structure with large specific surface area, the IL-styrene based PLOT-CEC column showed excellent separation efficiency towards multiple kinds of analytes with theoretical plates up to N = 322,277 N/m for phloroglucinol. And thanks to the high permeability and large EOF mobility generated by positively charged ionic liquid, the PLOT-CEC column showed good performance in CEC-MS analysis of parabens, amino acids and peptides with stable separation and ESI spray. Good repeatability with relative standard deviations for intra-day, inter-day runs and between tubes less than 4.94% was obtained.

Incorporation of homochiral metal-organic cage into ionic liquid based monolithic column for capillary electrochromatography.

Metal-organic cages (MOCs) are a novel kind of porous materials which have three dimensional structures with perpetual and well-defined holes. They have attracted wide consideration for relatively simple synthesis and potential applications such as separation, sensing, microreactor and catalysis etc. In this study, a homochiral MOC [Zn3L2] was prepared as a novel stereoselective stationary phase and added into poly (ionic liquid-co-ethylene dimethacrylate) (Zn3L2@poly(IL-co-EDMA)) monolith for capillary electrochromatography (CEC). The chiral analytes comprising mandelic acid, benzoin and furoin enantiomer were separated perfectly using the monolithic column Zn3L2@poly(IL-co-EDMA), and the effects of buffer pH, acetonitrile percentage and buffer concentration on enantiomers separation were confirmed. Moreover, incorporation of MOC [Zn3L2] into IL polymer monolith strengthened obviously the stereoselective isolation of some positional isomers (such as nitrophenols, nitrotoluenes, xylenes, and ionones). The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) and column-to-column (n = 3) enantioseparations were all below 5.0%. This novel monolithic column combined distinct features of the stereoselective materials with the eminent traits of ionic liquid matrix, it has great application potential in CEC.

Advances in capillary electro-chromatography.

Capillary electrochromatography (CEC) is a micro-scale separation technique which is a hybrid between capillary electrophoresis (CE) and liquid chromatography (LC). CEC can be performed in packed, monolithic and open-tubular columns. In recent three years (from 2016 to 2018), enormous attention for CEC has been the development of novel stationary phases. This review mainly covers the development of novel stationary phases for open-tubular and monolithic columns. In particular, some biomaterials attracted increasing interest. There are no significant breakthroughs in technology and principles in CEC. The typical CEC applications, especially chiral separations are described.

Analysis of Evodiae Fructus by capillary electrochromatography-mass spectrometry with methyl-vinylimidazole functionalized organic polymer monolilth as stationary phases.

Evodiae Fructus is used as a traditional Chinese medicine for the treatment of several kinds of diseases with its bioactive constituents. In this study, a capillary electrochromatography-mass spectrometry (CEC-MS) method was developed to determine three bioactive compounds including evodiamine, rutaecarpine and limonin in Evodiae Fructus fruit. Home-developed monolithic columns with methyl-vinylimidazole functionalized organic polymer monolilth as stationary phases were used in CEC-MS with excellent separation selectivity and high efficiency. The CEC-MS methods provided 4-16 folds improvement of LODs when compared with CEC-UV method. The conditions, which could affect separation efficiency and detection sensitivity, were optimized. Under optimum conditions, baseline separation with high detection sensitivity was obtained. The method showed good linearity (R2 >0.99) of 0.8-160 µg mL-1 with low limits of detection of 0.15-0.31 µg mL-1. Relative standard deviations of migration time and relative peak areas were <13.89%. Recoveries of evodiamine, rutaecarpine and limonin in Evodiae Fructus fruit were tested and calculated, which ranged from 102% to 113%. Finally, the three bioactive compounds in Evodiae Fructus herb samples from different regions were analyzed and studied. It has been demonstrated that the developed method has great potential for quality control of Evodiae Fructus herb.

A reversed-phase/hydrophilic bifunctional interaction mixed-mode monolithic column with biphenyl and quaternary ammonium stationary phases for capillary electrochromatography.

A novel organic polymer monolithic column with reversed-phase/hydrophilic (RPLC/HILIC) bifunctional interaction mixed-mode was successfully synthesized with the monomers 4-vinylbiphenyl and vinylbenzyl trimethylammonium chloride and the cross-linker ethylene dimethacrylate by in situ copolymerization in a binary porogenic solvent consisting of cyclohexanol and dodecanol for capillary electrochromatography. The stationary phases formed by styrene-based monomers can allow powerful π-π, hydrophobic and hydrophilic interactions, which is beneficial for the chromatographic separation with high resolution and high column efficiency. One mixed-mode monolithic column can work as two individual mode columns based on the combination of binary RPLC and HILIC separation mechanisms. Vanillin substances and neutral and alkaline compounds can be separated perfectly on the monolithic column in different chromatographic modes which can be switched by changing the content of the organic modifier in the running phase. For benzene, the highest column efficiency was 3.49 × 105 plates per m (theoretical plates, N). The relative standard deviations of retention time of different test analytes for intra-day (n = 5), inter-day (n = 5), column-to-column (n = 3) and batch-to-batch (n = 3) reproducibility were all less than 5.0%. All these results demonstrate that the monolithic column with RPLC/HILIC mixed-mode has great application potential.

Polydopamine-assisted immobilization of a zinc(II)-derived metal-organic cage as a stationary phase for open-tubular capillary electrochromatography.

A capillary column was modified with a soluble zinc(II)-derived metal-organic cage (MOC) [Zn2L] as the stationary phase to obtain a new coating layer for use in open-tubular capillary electrochromatography. The inner surface of the capillary was first coated with a layer of polydopamine. Then, a solution of the MOC in dichloromethane was introduced into the capillary upon which it is bonded both covalently and non-covalently. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results demonstrated the successful formation of the [Zn2L] modified open-tubular column. The column showed good separation performance towards neutral compounds (such as methylbenzene, ethylbenzene, n-propylbenzene and n-butylbenzene), acidic drugs (such as ibuprofen, ketoprofen, flurbiprofen and diclofenac sodium), food additives (such as parabens, vanillin and related phenolic compounds) and small biomolecules (such as nucleosides and nucleotide bases) by π-interaction and hydrophobic interaction. It also exhibited good precision, the relative standard deviations of the retention time for intra-day, inter-day runs and column-to-column being <1.6%, 2.8%, and 4.0%, respectively. Graphical abstract Schematic presentation of the open-tubular column modified with zinc(II)-derived metal-organic cage by polydopamine-assisted strategy onto the inner wall of capillary for electrochromatographic separations.

In-situ growth of a metal organic framework composed of zinc(II), adeninate and biphenyldicarboxylate as a stationary phase for open-tubular capillary electrochromatography.

This work reports on the in-situ growth of a metal organic framework (MOF) composed of zinc(II), adeninate and biphenyldicarboxylate on the inner wall of a capillary, and the use of this MOF as a stationary phases in open-tubular capillary electrochromatography. The inner wall of a fused-silica capillary was first modified with 3-aminopropyltriethoxysilane to create surface amino sites, and then the MOF was synthesized by in-situ growth. The modified capillary was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results proved the successful growth of the MOF. The resultant open-tubular column showed good separation selectivity towards neutral compounds, acidic and basic compounds including nonsteroidal anti-inflammatory drugs, sulfa drugs and small biomolecules. In addition, the modified column is stable and repeatable. The precisions (expressed as RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 5) separations and between columns (n = 3) are less than 0.5, 1.6 and 4.7%, respectively. Conceivably, this new kind of MOF represents a most useful novel stationary phase in electrochromatographic separations. Graphical abstract Schematic presentation of the open-tubular column modified with bio-MOF-1 by in situ hydrothermal reaction with adeninate, Zn(II) and biphenyldicarboxylate for capillary electrochromatographic separations.

Rapid proteolytic digestion and peptide separation using monolithic enzyme microreactor coupled with capillary electrophoresis.

Proteolytic digestion and peptide separation are key steps in proteomic study, which has attracted much attention. A novel immobilized trypsin microreactor based on monolithic capillary column was developed for rapid proteolytic digestion in this work. The monolithic support was prepared using itaconic acid as functional monomer within a silanized fused-silica capillary. By taking advantage of itaconic acid with two carboxylic functional groups, trypsin was covalently immobilized onto the monolithic support by condensation reaction. The performance of proteolytic digestion by the microreactor was evaluated with cytochrome C and bovine serum albumin, and the digests were further analyzed by CE and HPLC. Compared to those obtained by conventional in-solution digestion, the digestion time was shortened from 12 h to 40 s, demonstrating the high digestion efficiency of the prepared microreactor. Difference of protein separation results obtained by CE and HPLC highlighted the potential of CE in fast and highly efficient peptide separation in proteomic study. All the results demonstrated that the microreactor combined with CE could be a promising tool in workflow of proteomic analysis.

Ionic liquid-copolymerized monolith incorporated with zeolitic imidazolate framework-8 as stationary phases for enhancing reversed phase selectivity in capillary electrochromatography.

A novel ionic liquid (1-allyl-methylimidazolium chloride, AlMeIm+Cl-) polymer monolith poly(ionic liquid-co-ethylene dimethacrylate) incorporated with zeolitic imidazolate framework-8 (ZIF-8-poly(IL-co-EDMA)) was firstly synthesized as stationary phases of monolithic column for capillary electrochromatography by one-step copolymerization. Incorporation of ZIF-8 into ionic liquid polymer monolith evidently enhanced the separation selectivity for four alkylbenzenes in reversed phase capillary electrochromatography (CEC), due to the synergistic effect derived from the same imidazole ring structure of ionic liquid and organic ligands of ZIF-8. Meanwhile, electroosmotic flow (EOF) was generated by ionic liquid in a wide range of pH values from 2.0 to 12.0. The resultant monolithic columns were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The results indicated that the prepared monolithic columns had good permeability and mechanism stability. The resultant monolithic columns were applied for the separation of neutral compounds, anilines and phenols. The highest column efficiency was 2.07 × 105 plates m-1 (theoretical plates, N) for toluene. Under optimal conditions, reproducibility was obtained with relative standard deviations (RSDs) of the retention time for run-to-run, day-to-day, column-to-column and batch-to-batch were in the range of 1.58 - 3.19%, 1.92 - 3.87%, 3.84 - 4.96% and 2.63 - 4.33%, respectively. Incorporation ZIF-8 into ionic liquid polymer monolith was a promising way for the application of new materials in the fabrication of novel monolithic columns.

Monolithic column with polymeric deep eutectic solvent as stationary phase for capillary electrochromatography.

A novel monolithic column based on the copolymerization of ethylene dimethacrylate and a deep eutectic solvent (DES), which composed of chlorocholine chloride and itaconic acid, was developed for capillary electrochromatography (CEC). The structure and morphology of the obtained monolithic column was characterized by Fourier transform infrared spectra and scanning electron microscopy, which showed a porous monolithic structure with good permeability. The influence of pH value and acetonitrile content on electroosmotic flow (EOF) of DES-based monolithic column was investigated. The DES-based monolithic column was used as the separation column of CEC and exhibited excellent performance for the separation of neutral compounds, phenols, toluidines, nucleosides, nucleotide bases and alkaloids. The retention mechanism might be attributed to synergistic effect of hydrophobic interaction, hydrogen bond interaction and electronic interaction. The DES-based monolithic column showed good repeatability with relative standard deviations of migration time less than 0.80%, 2.15%, 4.26% and 3.08% for intra-day, inter-day, column-to-column and batch-to-batch, respectively. Thus, organic polymer monolithic columns with DESs as functional monomers are a promising option in chromatographic separation.

Monolithic column functionalized with quinine derivative for anion-exchange capillary electrochromatography.

A novel anion-exchange organic polymer monolithic column based on monomers N-benzylquininium chloride and acrylamide were firstly prepared by in situ copolymerization for capillary electrochromatography. Moreover, N-benzylquininium was firstly introduced as a strong anion-exchange functional group. A relatively strong anodic EOF was obtained in the pH values from 4.0 to 9.0, which was in the same direction with the electrophoretic mobility of acid compounds. Hence, the anion-exchange monolithic column was very suitable for the rapid separation of acid compounds. Eight acid compounds (2-chlorobenzoic acid, mandelic acid, 4-hydroxybenzoic acid, indole-3-acetic acid, 2-aminoterephthalic acid, 3,5-pyridinedicarboxylic acid, benzoic acid, and 4-aminobenzoic acid) were successfully separated on the monolithic column. The highest column efficiency was 4.60 × 105 plates/m (theoretical plates, N) for 3,5-pyridinedicarboxylic acid. The proposed monolithic column was characterized by SEM and FT-IR. The RSDs of the acid compounds migration time for run-to-run, day-to-day, and column-to-column were all less than 5.0%.