A star-shaped molecularly imprinted polymer derived from polyhedral oligomeric silsesquioxanes with improved site accessibility and capacity for enantiomeric separation via capillary electrochromatography.

A star-shaped molecularly imprinted coating was prepared starting from octavinyl-modified polyhedral oligomeric silsesquioxanes (Ov-POSS). It possesses a relatively open structure and has good site accessibility and a larger capacity even at lower cross-linking. The imprinted coating was prepared from S-amlodipine (S-AML) as the template and analyte, Ov-POSS as the cross-linker, and methacrylic acid as the functional monomer. The preparation and chromatographic parameters were optimized, including ratio of template to functional monomer, apparent cross-linking degree, pH value, ACN content and salt concentration in the mobile phase. The best resolution in enantiomer separation by means of capillary electrochromatography reaches a value of 33. A good recognition ability (α = 2.60) was obtained and the column efficiency for S-AML was 54,000 plates m-1. The use of Ov-POSS as a cross-linker significantly improves the column capacity and thus the detection sensitivity. The results show that Ov-POSS is an effective cross-linker for the preparation of imprinted polymers with good accessibility and large capacity. Graphical abstract Schematic presentation of the preparation of star-shaped imprinted polymer using octavinyl-modified polyhedral oligomeric silsesquioxanes (Ov-POSS) and by using methacrylic acid (MAA) as functional monomer. The best enantiometric resolution (33) for amlodipine (AML) can be achieved in capillary chromatography (CEC).

A polymer monolith incorporating stellate mesoporous silica nanospheres for use in capillary electrochromatography and solid phase microextraction of polycyclic aromatic hydrocarbons and organic small molecules.

An inorganic-organic hybrid monolith incorporated with stellated mesoporous silica nanoparticles (SMSNs) was prepared. Using binary solvents, deep eutectic solvents and room temperature ionic liquids, an SMSN-incorporated poly(butyl methacrylate-co-ethylene glycol dimethacrylate) monolith demonstrated uniform structure with good column permeability. A systematic investigation of preparation parameter was performed, including SMSN content, crosslinking monomer content, and the component of binary solvent. The optimized monoliths were characterized by field emission scanning electron microscopy, transmission electron microscopy, area scanning energy dispersive spectrometry, and nitrogen adsorption. Column performance was tested by separating four groups of analytes (alkylbenzenes, anilines, naphthalenes and phenols) by capillary electrochromatography (CEC). Baseline separation of all analytes was obtained with column efficiencies of up to 266,000 plates m-1. The performance of the resulting monolith was further investigated in detail by separating mixtures of polycyclic aromatic hydrocarbons (PAHs), nonsteroidal antiinflammatory drugs (NSAIDs), and hydroxybenzoic acid isomers. Compared with the corresponding SMSN-free monolith, the CEC performance was improved by about six times. Successful extraction of PAHs and quinolones (QNs) were also performed using this capillary. Improved extraction efficiency (20.2%) for complex samples, lake water, was also found when the material was applied to solid phase microextraction of fluoranthene. Graphical abstract A poly(butyl methacrylate-co-ethylene glycol dimethacrylate) monolith incorporated with stellated mesoporous silica nanoparticles was prepared. It demonstrated column efficiency up to 266,000 plates m-1 in capillary electrochromatography and ability as solid phase microextraction for organic small molecules with good column permeability.

Green synthesis of monolithic column incorporated with graphene oxide using room temperature ionic liquid and eutectic solvents for capillary electrochromatography.

In this work, a hybrid monolith incorporated with graphene oxide (GO) was prepared in the first time with binary green porogens of deep eutectic solvents (DESs) and room temperature ionic liquids (RTILs). GO was modified with 3-(trimethoxysilyl) propylmethacrylate (γ-MPS), and the resultant GO-MPS can be incorporated into poly (methacrylic acid-co-butylmethacrylate-co-ethylene glycol dimethacrylate) monoliths covalently. A hybrid monolithic column with high permeability and homogeneity can be achieved due to good dispersion of GO-MPS in the green solvents. The GO-MPS incorporated monolith was characterized by transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis and nitrogen adsorption tests. The separation of small organic molecules of alkylphenones and alkylbenzenes was used to evaluate the performance of GO-MPS grafted monolith. The GO-MPS grafted monolith displayed the maximum column efficiency of 147,000 plates/m, about twice higher than the GO-free monolith. In addition, all of the retention and selectivity of small molecules of alkylphenones and alkylbenzenes increased due to the addition of GO-MPS. The results demonstrated that the use of DESs and RTILs is a powerful approach for the preparation of GO incorporated polymer monoliths. The monolith was further applied to the separation of tryptic digests from bovine serum albumin, and the result indicated its potential in the analysis of some complex samples.

A Randomized Multicenter Clinical Trial of RPH With the Simplified Milligan-Morgan Hemorrhoidectomy in the Treatment of Mixed Hemorrhoids.

PURPOSE: To explore the safety and efficacy of Ruiyun procedure for hemorrhoids (RPH) or RPH with the simplified Milligan-Morgan hemorrhoidectomy (sMMH) in the treatment of mixed hemorrhoids. METHODS: This is a randomized, controlled, balanced, multicenter study of 3000 patients with mixed hemorrhoids. The outcomes and postoperative complications were compared between 5 types of surgeries. RESULTS: The efficacy rate was the highest in patients who received RPH+sMMH and decreased in the following order: patients who received RPH alone, MMH alone, procedure for prolapse and hemorrhoids (PPH) alone, and PPH+sMMH ( P < .05). The operation time was the shortest in patients who received RPH alone and increased in the following order: patients who received RPH+sMMH, PPH alone, MMH alone, and PPH+sMMH ( P < .01). The duration of postoperative hospitalization stay was the shortest in patients who received RPH alone and increased in the following order: PPH alone, RPH+sMMH, PPH+sMMH, and MMH alone ( P < .01). The incidence of postoperative hemorrhage, uroschesis, anal fissure, crissum hematoma or thrombosis, and anorectal stenosis was significantly lower in patients who received RPH+sMMH than in patients who received the other 4 types of surgical treatments ( P < .05, P < .01). No significant differences in postoperative rectovaginal fistula and anal incontinence were observed between the 5 groups of patients. CONCLUSIONS: RPH with or without simplified MMH can reduce the incidence of postoperative complications and improve the curative efficacy in the treatment of patients with mixed hemorrhoids.

Molecularly imprinted polymer prepared with polyhedral oligomeric silsesquioxane through reversible addition-fragmentation chain transfer polymerization.

Polyhedral oligomeric silsesquioxane (POSS) was utilized to prepare imprinted polymer through reversible addition-fragmentation chain transfer polymerization (RAFT) successfully. The imprinted polymer was made with a mixture of RAFT agent, 4-vinylpyridine (4-VP), POSS monomer [PSS-(1-propylmethacrylate)-heptaisobutyl substituted, MA 0702], and ethylene glycol dimethacrylate (EDMA), with ketoprofen (KET) as template. The influence of polymerization variables, the amount of RAFT agent and POSS monomer, the ratio of KET to 4-VP, and the ratio of 4-VP to EDMA, were investigated on the retention factor and imprinting effect. The greatest imprinting factor of the RAFT agent-based POSS MIP was 15.2, about 1.5 times higher than the RAFT agent-free agent POSS MIP. The permeability, surface morphology, as well as pore size distribution of POSS MIP monoliths made with RAFT agent and without RAFT agent were also studied. The optimal MIP was applied to solid phase extraction for KET from commercial tablets. The mean recoveries of KET for RAFT-based POSS MIP was 85.2% with a relative standard deviation of 2.6%.

[Treatment of Mixed Hemorrhoids by RPH with the Simplified Milligan-Morgan Surgery: a Multi-center, Randomized, Controlled Clinical Trial].

Objective To observe the safety and efficacy of RPH with the simplified. Milligan-Mor- gan(M-M) surgery on mixed hemorrhoids. Methods Totally 1 200 patients with mixed hemorrhoid were assigned to the control group(600 cases) and the treatment group(600 cases) according to randomized, parallel controlled,multi-center trial design. Patients in the control group received PPH with the simplified M-M surgery, and patients in the treatment group received RPH with the simplified M-M surgery. Postop- erative complications, operation time,the postoperative hospitalization days and the efficacy were ob- served. Results Compared with the control group, the numbers of postoperation hemorrhage, postop- erative uroschesis, anal fissure and anorectal stenosis in treatment group were decreased(P <0. 01 , P < 0. 05), operation time and the postoperative hospitalization days were decreased (P <0. 01 , P <0. 05 ), the cure rate for 3 and 12 months after operation were increased (P <0. 01, P <0. 05). Conclusions RPH with the simplified M-M surgery could reduce the incidence of postoperative complications,improve the clinical cure rate and the curative effect in treatment of mixed hemorrhoids.

Green synthesis of mesoporous molecular sieve incorporated monoliths using room temperature ionic liquid and deep eutectic solvents.

A hybrid monolith incorporated with mesoporous molecular sieve MCM-41 of uniform pore structure and high surface area was prepared with binary green porogens in the first time. With a mixture of room temperature ionic liquids and deep eutectic solvents as porogens, MCM-41 was modified with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and the resulting MCM-41-MPS was incorporated into poly (BMA-co-EDMA) monoliths covalently. Because of good dispersibility of MCM-41-MPS in the green solvent-based polymerization system, high permeability and homogeneity for the resultant hybrid monolithic columns was achieved. The MCM-41-MPS grafted monolith was characterized by scanning electron microscopy, energy dispersive spectrometer area scanning, transmission electron microscopy, FT-IR spectra and nitrogen adsorption tests. Chromatographic performance of MCM-41-MPS grafted monolith was characterized by separating small molecules in capillary electrochromatography, including phenol series, naphthyl substitutes, aniline series and alkyl benzenes. The maximum column efficiency of MCM-41-MPS grafted monolith reached 209,000 plates/m, which was twice higher than the corresponding MCM-41-MPS free monolith. Moreover, successful separation of non-steroidal anti-inflammatory drugs and polycyclic aromatic hydrocarbons demonstrated the capacity in broad-spectrum application of the MCM-41-MPS incorporated monolith. The results indicated that green synthesis using room temperature ionic liquid and deep eutectic solvents is an effective method to prepare molecular sieve-incorporated monolithic column.

Monolithic column incorporated with lanthanide metal-organic framework for capillary electrochromatography.

A new lanthanide metal-organic frameworks NKU-1 have successfully incorporated into poly (BMA-co-EDMA) monolith and evaluated by capillary electrochromatography (CEC). Lanthanide metal-organic frameworks [Eu2(ABTC)1.5(H2O)3(DMA)] (NKU-1) were synthesized by self-assembly of Eu(III) ions and 3,3',5,5'-azo benzene tetracarboxylic acid ligands have been fabricated into poly(BMA-co-EDMA) monoliths. 1-Butyl-3-methylimidazolium tetrafluoroborate and N,N-dimethylformamide were developed as binary porogen obtaining homogeneous dispersibility for NKU-1 and high permeability for monolithic column. The successful incorporation of NKU-1 into poly(BMA-co-EDMA) was confirmed and characterized by FT-IR spectra, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer area scanning, and transmission electron microscopy. Separation ability of the NKU-1-poly (BMA-co-EDMA) monoliths was demonstrated by separating four groups of analytes in CEC, including alkylbenzenes, polycyclic aromatic hydrocarbon, aniline series and naphthyl substitutes. Compared with bare monolithic (column efficiency of 100,000plates/m), the NKU-1-poly (BMA-co-EDMA) monoliths have displayed greater column efficiency (maximum 210,000plates/m) and higher permeability, as well as less peak tailing. The results showed that the NKU-1-poly (BMA-co-EDMA) monoliths are promising stationary phases for CEC separations.

Green synthesis of polymer monoliths incorporated with carbon nanotubes in room temperature ionic liquid and deep eutectic solvents.

In this work, an efficient method to prepare polymer monoliths with incorporated carbon nanotubes in a mixture of room temperature ionic liquid and deep eutectic solvents was developed. With assistance of the binary green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate and choline chloride/ethylene glycol, single-walled carbon nanotubes were dispersed successfully in pre-polymerization mixture without need of oxidative cutting of carbon nanotubes, which may allow depletion of the emission of volatile organic compounds into environment. The novel single-walled carbon nanotubes monolith was evaluated by capillary electrochromatography. Compared with the monolith made without single-walled carbon nanotubes, the monolith with the incorporation of single-walled carbon nanotubes exhibited high column efficiency (251,000plates/m) in the chromatographic separation. The morphology of the monolith can be tuned by the composition of mixture of ionic liquids and deep eutectic solvents to afford good column permeability and excellent separation ability for small molecules of alkyl phenones and alkyl benzenes. The results demonstrated that the method is a green strategy for the fabrication of multifunctional polymer monoliths.

Coatings of molecularly imprinted polymers based on polyhedral oligomeric silsesquioxane for open tubular capillary electrochromatography.

Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic coating for capillary electrochromatography. The imprinted monolithic coating was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), S-amlodipine (template), methacrylic acid (functional monomer), and 2-methacrylamidopropyl methacrylate (crosslinker), in a porogenic mixture of toluene-isooctane. The influence of synthesis parameters on the imprinting effect and separation performance, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest resolution for enantiomers separation on the imprinted monolithic column prepared with MA 0702 was up to 22.3, about 2 times higher than that prepared in absence of the POSS. Column efficiency on the POSS-based MIP coatings was beyond 30,000 plate m(-1). The comparisons between MIP coating synthesized with the POSS and without the POSS were made in terms of selectivity, column efficiency, and resolution. POSS-based MIP capillaries with naproxen or zopiclone was also prepared and separation of enantiomers can be achieved.

Supermacroporous polymer monolith prepared with polymeric porogens via viscoelastic phase separation for capillary electrochromatography.

Supermacroporous poly(methacrylic acid-butyl methacrylate-ethylene glycol dimethacrylate) monoliths with the pore size up to 5-10 µm were successfully prepared in a ternary polymeric porogens utilizing viscoelastic effect. High concentration (over 20 mg/mL) of polystyrene (PS) in porogen was used to achieve the desirable characteristics of the monolithic capillary. Modification of the co-porogen composition, i.e., the content of dimethyl sulfoxide and isooctane, enabled tailoring of the supermacropore structure with a wide range of pore size. The effects of the amount of polymer porogen and molecular weights of PS on the formation of supermacropore were also studied. In preliminary applications, the separations of alkyl phenones and alkylbenzenes were achieved on the supermacropore columns using a mode of capillary electrochromatography. The study demonstrated successfully the ability of polymer porogen to form supermacropore monolith via viscoelastic phase separation.