Ethylene Dimethacrylate Research Articles

Design and fabrication of acorn-like Janus molecularly imprinted materials for highly specific separation and enrichment of oxytetracycline from restaurant oily wastewater

Molecularly imprinted polymer (MIP) is dedicated to the adsorption of target substances in the aqueous phase, but ignores the adsorption in a more complex environment (oily wastewater). In order to explore the application field of existing MIPs, acorn-like Janus particles were fabricated by photo-initiated seed swelling polymerization. A novel amphiphilic Janus-MIP was prepared with the acorn-like Janus particles as matrix, methacrylic acid, ethylene dimethacrylate and oxytetracycline (OTC) as functional monomers, crosslinking agents and template molecules via surface initiated-atom transfer radical polymerization (SI-ATRP). For comparison, the poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) (poly (GMA-co-EDMA)) microspheres were also utilized as the matrix to prepare common spherical-MIP. The adsorption capacity of Janus-MIP for OTC was 23.8 mg g−1 in oil-water system, while the adsorption capacity of spherical-MIP for OTC was only 12.6 mg g−1 in the same system. At the same time, through high performance liquid chromatography (HPLC) analysis, Janus-MIP can specifically recognize and adsorb trace OTC in restaurant oily wastewater samples, and the proposed method exhibited a lower limit of detection (LOD, 3 ng mL−1) and a higher OTC recovery rate (94.2 %–98.4 %). This work demonstrated great potential for the detection and control of OTC contamination from real samples in an oil-water mixed environment.

Effect of carbon dot on preparation of dual-functional Janus particles via photo-initiated seed swelling polymerization

With the development of industry, the detection and removal of heavy metal ions from water has received much attention. Janus particles are distinguished from many other materials by their unique structure and functionalization. We proposed a simple photo-initiated seed swelling polymerization method for preparing carbon dot-coated dual-functional Janus particles (Janus@CD), using glycyl methacrylate (GMA) as monomer and ethylene dimethacrylate (EDMA) as crosslinker. In order to modulate the particle morphology during the phase separation process, carbon dot (CD) was added to the reaction system. The results demonstrated that the presence of CD had a significant effect on the shape of Janus particles. Furthermore, Janus@CD could be directly applied in the adsorption and detection for MnO4−. The limit of detection (LOD) was 6.39 nmol L−1, and the maximum adsorption capacity was 23.9 mg g−1, in line with the Langmuir adsorption model. The adsorption equilibrium reached within 30 min. The results demonstrated that dual-functional Janus@CD would present great potential in the detection and enrichment for metal ions.

Effect of anionic groups in zwitterionic hydrophilic stationary phases on their chromatographic characteristics

The structure of zwitterion has great impact on the separation properties of zwitterionic hydrophilic stationary phases. To better understand the role of anionic groups of zwitterions, a novel carboxybetaine-based zwitterionic monolithic column was first prepared through thermo-initiated copolymerization of functional monomer (3-acrylamidopropyl)-dimethyl-(2-carboxymethyl) ammonium (CBAA) and crosslinker ethylene dimethacrylate (EDMA) within 100 μm ID capillary. The optimal poly(CBAA-co-EDMA) monolithic column exhibited satisfactory mechanical and chemical stability, good repeatability, high column efficiency (96,000 plates/m), and excellent separation performance for different classes of polar compounds (i.e., phenols, monophosphate nucleotides, urea and allantoin). A comparative study was then performed among three zwitterionic hydrophilic stationary phases containing different anionic groups, i.e. poly(CBAA-co-EDMA) (carboxybetaine), poly(2-{2-(methacryloyloxy) ethyldimethylammonium}ethyl n-butyl phosphate-co-EDMA) (phosphocholine), and poly(N,N-dimethyl-N-(3-methacrylamidopropyl)-N-(3-sulfopropyl) ammonium betaine-co-EDMA) (sulfobetaine) using benzoic acid derivatives, amine compounds, nucleobases and nucleosides as model analytes. The carboxybetaine-based monolithic column exhibited much higher positive zeta-potential and hydrophilicity, which endows it with a stronger retention capacity for acidic and neutral compounds, but sulfobetaine-based monolithic column exhibited much higher selectivity and retention capacity for the amines. Moreover, their enrichment efficiencies for N-glycopeptides were also evaluated based on their different hydrophilicity, and it was observed that the poly(CBAA-co-EDMA) monolithic material captured 4-8 times more N-glycopeptides compared to the other two materials.

Synthesis of micro-crosslinked adamantane-containing matrix resins designed for deep-UV lithography resists and their application in nanoimprint lithography.

A certain type of photoresist used for deep-UV lithography (DUVL) can also be used for other types of photolithography. Thus, to meet the requirements of two or more lithography technologies simultaneously, it is necessary to design a variety of corresponding functional groups in the molecules of materials and obtain the required properties. Herein, we designed four matrix resins based on acrylate for DUVL, employing alkyl sulfide, adamantane, methyladamantane, and hydroxyl as dangling groups and a microcrosslinking network by adding a small amount of crosslinker. These polymers were used in the thermal nanoimprint lithography (NIL) process, and distinct patterns with a resolution of 100 nm were observed. The acrylate copolymers designed for DUVL in this work can be used as thermal NIL resists and to obtain good patterns. It was found that ethylene dimethacrylate (EDMA) and adamantane endowed the matrix resins with good thermal stability and that PMMHM demonstrated the best patterning performance among the four resins. These polymers can be applied in the manufacturing of high-density integrated circuits, nano-transistors, optoelectronic devices and other components in the future.

Simple surface modification of polypropylene pipette tips for anchoring of organic monolithic-based materials for micro-solid-phase extraction

This paper presents a simple method for the surface modification of polypropylene pipette tips by adsorbing a photo-initiator, 2,2-dimethoxy-2-phenylacetophenone (DMPAP), to create reactive sites for the formation of a layer of ethylene dimethacrylate (EDMA) and subsequent monolith polymerization. The types of monomers and the degree of crosslinking dramatically affected the monolith shrinkage and detachment in unmodified tips. Effective surface modification for anchoring monolithic materials to pipette tips was achieved using 15 wt% DMPAP and 10 wt% EDMA in methanol with UV irradiation at 365 nm. The extraction of 5-hydroxyindoleacetic acid, serotonin, and bisphenol A (BPA) using methacrylate and activated charcoal composite monoliths was investigated in terms of breakthrough capacity. The application of monolithic pipette tip micro-solid-phase extraction followed by HPLC-UV was demonstrated for determining BPA leaching from baby-feeding bottles and canned foods. Wide linearity ranging from 0.1 to 100 ng mL−1 (R2 = 0.9998) with good repeatability (% RSD = 3.9 %) and accuracy (% recovery = 93–106 %) was obtained. The limit of detection and limit of quantification were 0.084 and 0.280 ng mL−1, respectively. By varying the sample loading volume from 0.50 to 10.00 mL with eluting volume of 150 μL, a 2-to-52-fold pre-concentration factor was observed.

A novel chiral monolithic nano-column with 50 µm i.d. for the enantioseparation of chiral drugs by nano-liquid chromatography

A novel chiral monolithic nano-column was developed for the enantioseparation of chiral drugs by nano-liquid chromatography (nano-LC). The monolithic capillary with 50 µm i.d. was first prepared by an in-situ polymerization using butyl methacrylate (BuMA), ethylene dimethacrylate (EDMA) and NFMoc-Lysine modified GO nanoparticles. The final monolithic stationary phase was characterized by using FT-IR spectra of synthesized structures, scanning electron microscopy (SEM) and chromatographic analyses. After characterization, the prepared chiral monolithic column was investigated for the chiral separation of pharmaceutical racemates, including anti-inflammatory drugs (e.g., ketoprofen, ibuprofen, naproxen, etodolac and flurbiprofen) and β-blockers (e.g. propranolol, metoprolol and atenolol). It was demonstrated that NFMoc-Lysine modified GO nanoparticles incorporated chiral monolith could be successfully developed while this chiral monolith allowed sensitive chiral separation of chiral drugs. The chiral separation could be mostly achieved via the formation of π-π interactions as well as hydrophilic interactions between chiral stationary phase and enantiomers

Preparation of chiral monoliths with new modulation of the monolith surface chemistry for the enantioseparation of chiral drugs by nano-liquid chromatography

Here, we report the preparation and application of two new chiral monoliths for the enantioseparation of chiral drugs in nano-LC. Using 3‑chloro-2-hydroxypropylmethacrylate (HPMA-Cl, 2) as a precursor monomer, two different chiral monomers namely, Nα-Boc-Lys-HPMA (3A) and Nα-Fmoc-Lys-HPMA (3B) were synthesized and used for the preparation of chiral polymer monoliths. The first monolithic column (referred to as monolith I) was prepared by an in-situ polymerization of Nα-Boc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate while the second monolithic column (referred to as monolith II) was prepared by an in-situ polymerization of Nα-Fmoc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate as the crosslinker. Methanol and 1-propanol were used as the porogenic solvents. The prepared chiral monoliths were investigated for the enantioseparation of chiral drugs, including β-blockers (e.g., atenolol, propranolol, metoprolol) and anti-inflammatory drugs (e.g., ketoprofen, ibuprofen, flurbiprofen, naproxen, etodolac). The enantioseparation could be achieved via the formation of π-π interactions on the aromate-rich and aromate-poor chiral molecules while enantioseparation mechanism of chiral drugs included mostly π-π interactions and hydrogen bonding. Monolith II showed better enantioselectivity than Monolith I and the resolution values up to 2.12 were successfully achieved.

Hydrophobic Cross-Linked Chains Regulate High Wet Tissue Adhesion Hydrogel with Toughness, Anti-hydration for Dynamic Tissue Repair.

Hydrogel adhesion materials are widely reported for tissue engineering repair applications, however, wet tissue surface moisture can reduce the wet-adhesion properties and mechanical strength of hydrogels limiting their application. Here, anti-hydration gelatin-acrylic acid-ethylene dimethacrylate (GAE) hydrogels with hydrophobic cross-linked chains are constructed. The prepared GAE hydrogel is soaked in PBS (3 days) with a volume change of 0.6 times of the original and the adhesive strength, Young's modulus, toughness, and burst pressure are maintained by ≈70% of the original. A simple and universal method is used to introduce hydrophobic chains as cross-linking points to prepare hydrogels with anti-hydration, toughness, and high wet state adhesion. The hydrophobic cross-linked chains not only restrict the movement of molecular chains but also hinder the intrusion of water molecules. Antihydration GAE hydrogels exhibit good biocompatibility, slow drug release, and dynamic oral wet-state tissue repair properties. Therefore, the anti-hydration hydrogel has excellent toughness, wet tissue adhesion properties, and good prospects for biological applications.

Fabrication of a biochar-doped monolithic adsorbent and its application for the extraction and determination of coumarins from Angelicae Pubescentis Radix

A monolithic adsorbent was designed aiming to the structure of osthole and columbianadin, and fabricated using diallyl phthalate as the monomer and ethylene dimethacrylate as the crosslinker with the addition of bamboo biochar, via polymerization reaction in a stainless-steel tube. The prepared composite adsorbent packed in the tube was used as a solid-phase extraction column for the extraction and determination of two coumarins (osthole and columbianadin) in Angelicae Pubescentis Radix, combing with a C18 analytical column through an HPLC instrument, which show excellent matrix-removal ability and good selectivity to osthole and columbianadin. Furthermore, the present adsorbent shows good applicability, which was used for the extraction of osthole from Duhuo Jisheng Pill. Compared to the commercial C18 and phenyl adsorbent, the present adsorbent own better selectivity and higher resolution. These results attributed to the enhanced specific surface area (141 m2/g) and enriched interaction sites of the resulting composite adsorbent, due to the doping of bamboo biochar, which can produce hydrogen bond, dipole-dipole, π-π and hydrophobic force interactions with the osthole and columbianadin. The methodology validation indicated that the present method showed good precision and good accuracy, and the composite adsorbent showed good preparative repeatability, which can be reused for no less than 100 times with the relative standard deviation ≤4.6 % (n = 100). The present work provided a simple and efficient method for the extraction and determination osthole and columbianadin from Angelicae Pubescentis Radix.

Synthesis and characterization of ammonium polymer for anion removal in aqueous solutions

In a one-step thermal process using 2-[(methacryloyloxy)ethyl]trimethylammonium chloride (META), an ammonium polymer was successfully obtained for the removal of anions (nitrates, nitrites, and phosphates) from aqueous solutions. Ethylene dimethacrylate (EDMA) was used as a cross-linking agent. The effect of cross-linking agent, porogen, and polymerization time on the structure and physical properties of the obtained polymer was examined (FTIR, SEM, BET, elemental analysis). The optimal conditions for META synthesis were a monomer to porogen ratio of 20:80, 75% functional monomer content and a 12-hour polymerization time.

Durable and mechanically robust superhydrophobic radiative cooling coating

Passive radiative cooling (PRC) presents a promising strategy for reducing energy consumption by reflecting sunlight and radiating heat through atmospheric windows. Although extensive progresses have been achieved in efficient radiative cooling, it still faces several challenges that hinder its practical implementation, such as susceptibility to contamination, vulnerability to mechanical damage, and poor resistance to aging and corrosion. Herein, we report a robust superhydrophobic porous coating with nano-globules (SHPo-ME) for efficient all-day passive radiative cooling, which is thermal polymerized by Methyl methacrylate (MMA) and Ethylene dimethacrylate (EDMA). Due to the sufficient scattering by the nano-globule structures and the stretching vibration of the chemical bonds in the polymer, the SHPo-ME coating exhibits superior solar reflectance (97.6 %) and long-wave infrared emittance (98.3 %), realizing sub-ambient cooling of 8.4℃ under the solar intensity of 820 W⋅m−2 and 5.8℃ in the night. Moreover, the interconnected nano-globules increase the surface roughness, rendering the surface to exhibit remarkable superhydrophobicity with contact angle of up to 165° and sliding angle lowered to 2.4°. Importantly, the robust SHPo-ME coating possesses excellent self-cleaning ability, mechanical stability, recoverable superhydrophobicity, and anti-aging/anti-corrosion property. The as-prepared SHPo-ME coating can also be milled into powder and used as paint. This paint can be efficiently sprayed onto any arbitrary substrates on a large scale, demonstrating great potential for long-term outdoor application such as buildings, vehicles, electric equipment, and so forth.

Characterization of hybrid organo-silica monoliths for possible application in the gradient elution of peptides.

We characterized thermally polymerized organo-silica hybrid monolithic capillaries to test their applicability in the gradient elution of peptides. We have used a single-pot approach utilizing 3-(methacryloyloxy)propyltrimethoxysilane (MPTMS), ethylene dimethacrylate (EDMA), and n-octadecyl methacrylate (ODM) as functional monomers. The organo-silica monolith containing MPTMS and EDMA was compared with the stationary phase prepared by adding ODM to the original polymerization mixture. Column prepared using a three-monomer system provided a lower accessible volume of flow-through pores, a higher proportion of mesopores, and higher efficiency. We utilized isocratic and gradient elution data to predict peak widths in gradient elution. Both protocols provided comparable results and can be used for peptide peak width prediction. However, applying gradient elution data for peak width prediction seems simpler. Finally, we tested the effect of gradient time on achievable peak capacity in the gradient elution of peptides with a column prepared with a three-monomer system providing a higher peak capacity. However, the performance of hybrid organo-silica monolithic stationary phases in gradient elution of peptides must be improved compared to other monolithic stationary phases. The limiting factor is column efficiency in highly aqueous mobile phases, which needs to be focused on.

Cadmium ion-imprinted polymers for adsorption and detection of cadmium ions

Cadmium is a typical heavy metal ion. Long-term exposure to cadmium can lead to diseases like renal tubular dysfunction and bone degeneration. Therefore, it is necessary to develop efficient separation methods and detection techniques for cadmium ions. In this paper, adsorption enrichment was combined with detection to rapidly detect cadmium ions in water. Cadmium ion imprinted polymers (Cd(II)-IIPs) were prepared by bulk polymerization using Cd(II) as template ion, itaconic acid (IA) as functional monomer, ethylene dimethacrylate (EGDMA) as cross-linker, 4-(2-pyridylazo)-resorcinol (PAR) as chromogenic ligand, and azobisisobutyronitrile (AIBN) as initiator. The preparation conditions were optimized and the prepared Cd(II)-IIPs were characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state 13C nuclear magnetic resonance (13C NMR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS). In the adsorption experiment, the adsorption equilibrium was reached within 10 min in a solution of pH 7.0, and the saturation adsorption capacity of IIPs and NIPs were 50.542 mg·g−1 and 33.762 mg·g−1, respectively. The Cd(II)–IIPs exhibited selectivity for Cd(II) ions in the presence of Ni(II), Fe(II), Co(II), Cu(II), and Pb(II) ions; and after eight adsorption–desorption cycles, the adsorption capacity of Cd(II)-IIPs retained > 90%. In addition, the detection performance of the Cd(II)-IIPs was investigated by digital image colorimetric (DIC) and ultraviolet spectrophotometric methods; the detection limits were 1.46 and 1.74 μg·L−1, respectively, and the quantitative detection range was 8–100 μg·L−1. The Cd(II)-IIPs exhibited excellent adsorption properties and an obvious color gradient variation, which could be used for quantitative colorimetric detection over a range of concentrations.

Fluorescent poly[N‐(2‐hydroxypropyl) methacrylamide] nanogel by dispersion polymerization as a contrast agent for live‐cell imaging

AbstractHere, we report a novel dispersion polymerization for the preparation of cross‐linked poly[N‐(2‐hydroxypropyl) methacrylamide] (PHPMA)‐based nanogels in water/2‐methoxyethanol mixture (H2O/MetCel), initiated with potassium persulfate (KPS), and stabilized with poly(vinyl alcohol) 25/140 (PVA) and sodium dodecyl sulfate (SDS). Obtained nanogels were characterized using transmission (TEM) and cryogenic transmission electron microscopy (cryo‐TEM), dynamic light scattering (DLS), asymmetric flow field‐flow fractionation (A4F), nuclear magnetic resonance spectroscopy (NMR), and Raman spectroscopy methods in terms of size, particle size distribution, morphology, and structure. N‐(2‐hydroxypropyl) methacrylamide (HPMA) was copolymerized with 20 wt% ethylene dimethacrylate (EDMA) resulting in 138 nm poly[N‐(2‐hydroxypropyl) methacrylamide‐co‐ethylene dimethacrylate] (PHPMA‐EDMA) nanogel dispersion with irregular shape and core‐shell type structure. Next, we copolymerized HPMA with 20 wt% EDMA and 10 wt% propargyl methacrylate (PMA) to incorporate reactive functionality into the final core‐shell type 120 nm poly[N‐(2‐hydroxypropyl) methacrylamide‐co‐ethylene dimethacrylate‐co‐propargyl methacrylate] (PHPMA‐EDMA‐PMA) nanogel dispersion. Then, the biocompatibility of PHPMA‐EDMA‐PMA nanogel was proved using rat mesenchymal stem cells (rMSC), and human foreskin fibroblasts (BJ). PHPMA‐EDMA‐PMA nanogel was fluorescently labeled with sulfo‐cyanine3 azide resulting in 131 nm nanogel. We performed in vitro uptake studies with fluorescently labeled PHPMA‐EDMA‐PMA nanogel using rMSC showing that the fluorescently labeled PHPMA‐EDMA‐PMA nanogel was well‐distributed in the cytosol and taken up into lysosomes.

Evaluation of a Resorcinarene-Based Sorbent as a Solid-Phase Extraction Material for the Enrichment of L-Carnitine from Aqueous Solutions

We present five new sorbents for the evaluation of the pre-concentration of L-carnitine. The sorbents were obtained from copolymerization between butylmethacrylate (BuMA) and ethylene dimethacrylate (EDMA), which were physically modified on their surface by each one of the five synthetized resorcinarenes of variable chain length studied, with long-chain resorcinarenes exhibiting better fixation on the copolymer. The characterization of the synthesized resorcinarenes was done using FTIR-ATR, 1H NMR, 13C NMR, and mass spectrometry, while characterization of the sorbents was done using FTIR-ATR and scanning electron micrography (SEM). The molecular interaction between L-carnitine and the synthesized resorcinarenes was studied in DMSO via 1H-NMR spectroscopy and, in the gas phase, via electrospray ionization-mass spectrometry (ESI-MS). The results showed that the short-chain resorcinarenes underwent a stable interaction with the neurotransmitter. Once the sorption of resorcinarenes on the copolymer was accomplished, the best parameters for the evaluation of the L-carnitine preconcentration were established. The solution tests were carried out through LC/MS analysis, obtaining better results for L-carnitine absorption with the short-chain resorcinarenes such as tetra(ethyl)calix[4]resorcinarene and tetra(propyl)calix[4]resorcinarene.

Enhanced performance of ZIF-8 nanocrystals hybrid monolithic composites via an in-situ growth strategy for efficient capillary microextraction of perfluoroalkyl phosphonic acids

Enrichment of perfluoroalkyl phosphonic acids (PFPAs) is of great significance and challenging for environmental monitoring, due to their toxic and persistent nature, highly fluorinated character as well as low concentration. Herein, novel metal-organic frameworks (MOFs) hybrid monolithic composites were prepared via metal oxide-mediated in situ growth strategy and utilized for capillary microextraction (CME) of PFPAs. A porous pristine monolith was initially obtained by copolymerization of the zinc oxide nanoparticles (ZnO-NPs)-dispersed methacrylic acid (MAA) with ethylenedimethacrylate (EDMA) and dodecafluoroheptyl acrylate (DFA). Afterwards, nanoscale-facilitated transformation of ZnO nanocrystals into the zeolitic imidazolate framework-8 (ZIF-8) nanocrystals was successfully realized via the dissolution-precipitation of the embedded ZnO-NPs in the precursor monolith in the presence of 2-methylimidazole. Experimental and spectroscopic results (SEM, N2 adsorption-desorption, FT-IR, XPS) revealed that the coating of ZIF-8 nanocrystals significantly increased the surface area of the obtained ZIF-8 hybrid monolith and endowed the material abundant surface-localized unsaturated zinc sites. The proposed adsorbent showed highly enhanced extraction performance for PFPAs in CME, which was mainly ascribed to the strong fluorine affinity, Lewis acid/base complexing, anion-exchange, and weakly π-CF interaction. The coupling of CME with LC-MS enables effective and sensitive analysis of ultra-trace PFPAs in environment water and human serum. The coupling method demonstrated low detection limits (2.16–4.12 ng L−1) with satisfactory recoveries (82.0–108.0%) and precision (RSDs ≤6.2%). This work offered a versatile route to design and fabricate selective materials for emerging contaminant enrichment in complicated matrices.

Styrene-free unsaturated polyester resins derived from itaconic acid curable by cobalt-free accelerators

A series of polyester prepolymers was synthesized from itaconic acid, phthalic anhydride, propane-1,2-diol and diethylene glycol by condensation polymerization. The use of itaconic acid as a source of unsaturation (instead of more common maleic anhydride giving fumarate moieties) enabled to replace styrene reactive diluent by methyl methacrylate. Room temperature curing of a model polyester resin was initiated by butanone peroxide in combination with several cobalt-, iron- and vanadium-based accelerators. Measurements of gelation time and exothermic behavior in thermally isolated installation revealed very promising catalytic properties for oxidovanadium(IV) dibutylphosphate. In follow-up tests, mechanical properties of the model unsaturated polyester resin were tuned by variation in propane-1,2-diol/diethylene glycol ratio and composition of acrylate/methacrylate reactive diluent. Mixtures of methyl methacrylate with secondary crosslinking agents (e.g., ethylene dimethacrylate, triethyleneglycol dimethacrylate and trimethylolpropane triacrylate) enabled to improve ultimate tensile strength, Young’s modulus, tensile toughness and impact toughness. Reported experimental data indicate that the described styrene- and cobalt-free system is very promising for reduction in health and ecological issues of currently used unsaturated polyester resins curable at room temperature.Graphical

Methacrylate bonded covalent organic framework monolithic column online coupling with high-performance liquid chromatography for analysis of trace estrogens in food

Covalent organic frameworks (COFs) are a burgeoning class of crystalline porous materials with unique properties and have been considered as a promising functional extraction medium in sample pretreatment. In this study, a new methacrylate-bonded COF (TpTh-MA) was well designed and synthesized via the aldehyde-amine condensation reaction, and the TpTh-MA was incorporated into poly (ethylene dimethacrylate) porous monolith by a facile polymerization reaction inside capillary to prepare a novel TpTh-MA monolithic column. The fabricated TpTh-MA monolithic column was characterized with scanning electron microscope, Fourier transform infrared spectrometer, X-ray diffraction, and N2 adsorption–desorption experiments. Then, the homogeneous porous structure, good permeability and high mechanical stability of TpTh-MA monolithic column was used as separation and enrichment media of capillary microextraction, which was coupled with high-performance liquid chromatography fluorescence detection for online enrichment and analysis of trace estrogens. The main experimental parameters influencing the extraction efficiency were systematically investigated. The adsorption mechanism for three estrogens was also explored and discussed based on hydrophobic effect, π-π affinity and hydrogen bonding interaction, which contributed to its strong recognition affinity to target compounds. The enrichment factors of the TpTh-MA monolithic column micro extraction method for the three estrogens were 107–114, indicating a significant preconcentration ability. Under optimal conditions, a new online analysis method was developed and exhibited good sensitivity and wide linearity range of 0.25–100.0 µg·L-1 with a coefficient of determination (R2) higher than 0.9990 and a low limit of detection with 0.05–0.07 µg·L-1. The method was successfully applied for online analysis of three estrogens of milk and shrimp samples and the recoveries obtained from spiking experiments were in range of 81.4–113% and 77.9–111%, with the relative standard deviations of 2.6–7.9% and 2.1–8.3% (n = 5), respectively. The results revealed the great potential for the application of the COFs-bonded monolithic column in the field of sample pretreatment.

Accuracy of Three-Dimensional Printed Dental Models Based on Ethylene Di-Methacrylate-Stereolithography (SLA) vs. Digital Light Processing (DLP)

Additive manufacturing is a technology that has many uses across a variety of fields. Its usage spans many fields, including the fields of art, design, architecture, engineering and medicine, including dentistry. The study aims to evaluate and compare the accuracy of three-dimensional printed dental models based on ethylene di-methacrylate using the SLA and DLP techniques. For evaluation, a reference model containing 16 maxillary permanent molars was chosen. An ATOS Capsule 3D scanner was used to scan the reference model. Using a photo-cured liquid resin, eight three-dimensional printed models were obtained using the reference model as benchmark. Four of the models (A1–A4) were obtained using SLA printing technology and four models (B1–B4) were manufactured using DLP printing technology. A standard best fit method was used to pre-align the reference and the printed model surfaces. The height of the teeth, and the mesial–distal and buccal–lingual distances were analyzed. The assessment of the two manufacturing methods was achieved by using non-parametric tests to compare the mean ranks for the assessed features. The results show that models obtained through DLP had a higher precision but also a higher bias. Both methods still are within the required accuracy range for dental models.

Nano-Liquid Chromatography with a New Monolithic Column for the Analysis of Coenzyme Q10 in Pistachio Samples.

Coenzyme Q10 (CoQ10) is a vital substance found throughout body. It helps convert food into energy and is eaten small amounts in foods. CoQ10 has gained great interest in recent years as a potential candidate for the treatment of various diseases. The content of CoQ10 in food samples is a crucial quality index for foods. Therefore, the development of sensitive separation and quantification method for determining the amount of CoQ10 in various samples, especially in foods, is an important issue, especially for food nutrition. In this study, a new, miniaturized monolithic column was developed and applied for the determination of CoQ10 in pistachio samples by nano-liquid chromatography (nano-LC). The monolithic column with a 50 µm i.d. was prepared by in situ polymerization using laurylmethacrylate (LMA) as the main monomer and ethylene dimethacrylate (EDMA) as the crosslinker. Methanol (MeOH) and polyethyleneglycol (PEG) were used as porogenic solvents. The final monolithic column was characterized by using scanning electron microscopy (SEM) and chromatographic analyses. The monolithic column with a 50 µm i.d. was applied to the analysis of CoQ10 in pistachio samples in nano-LC. This analytical method was validated by means of sensitivity, linearity, precision, recovery, and repeatability. The LOD and LOQ values were 0.05 and 0.48 µg/kg, respectively. The developed method using the monolithic column was optimized to achieve very sensitive analyses of CoQ10 content in the food samples. The applicability of the method was successfully demonstrated by the analysis of CoQ10 in pistachio samples.