Solid-phase Preparation Research Articles

Characterization and biological activity evaluation of water-soluble resveratrol complexes obtained by spray drying, ball milling and jet milling

To increase the water solubility of resveratrol (RES) and explore the possibility of solid-phase preparation technology as an alternative to traditional spray drying technology. In this study, herein, three resveratrol-stevia glycoside-hydroxypropyl-β-cyclodextrin (RES-STE-HP-β-CD) complexes were prepared by jet milling, ball milling and spray drying. The three complexes were subjected to saturation solubility determination, characterization (SEM, XRD, FT-IR and 1H NMR), antioxidant activity evaluation and in vitro cytotoxicity assay. The results demonstrated that RES was successfully complexed with STE and HP-β-CD, and the crystalline state of RES was changed after the complexation. The water solubility of RES increased about 30 times, and the saturated solubility of the complexes prepared by jet milling reached the highest of 993.32 μg/mL. Meanwhile, RES could interact with STE through hydrogen bonding, and also could be probably inserted into the cavities of HP-β-CD. Moreover, the complexes prepared by different methods possessed good antioxidant activity and did not exhibit significant cytotoxicity. In conclusion, STE&HP-β-CD can effectively solubilize RES, and solid-phase preparation technologies (e.g., jet milling) have the potential to prepare water-soluble complexes. The complex powders can be used as raw materials for nutraceuticals or pharmaceuticals.

Solid-phase preparation of defective carbon supported PtNi alloy electrocatalyst and analysis of its oxygen reduction mechanism

In the present work, PtNi-loaded defective carbon (Pt/ZnPPC) was prepared by solid-phase method. Carbon support with specific defect types, such as Zn metal nitrogen carbon (ZnPPC850), N-doped carbon (ZnPPC950) and defective carbon (ZnPPC1050), were selectively obtained by optimizing the pyrolysis temperature to explore the effect of defect types on oxygen reduction reactions (ORR). Electrochemical measurements showed that the half-wave potential of the PtNi metal nanoparticle-loaded ZnPPC1050 catalyst (PtNi-ZnPPC1050) outperformed the commercial JM-Pt/C by 35 mV, and by 45 mV compared to the PtNi-loaded ZnPPC950 catalyst (PtNi-ZnPPC950), suggesting that the defects in the ZnPPC1050 support resulting from the evaporation of N by pyrolysis can interact well with Pt metal electrically, allowing the PtNi nanoparticles to be uniformly distributed. Meanwhile, the defects lead to the carrier containing a large number of active sites making its catalytic performance even much better than the pyridine nitrogen sites in ZnPPC950. The carbon defect structure is loosened and porous with high specific surface area, which can effectively load PtNi nanoparticles and enhance the mass transfer. We obtained a new bimetallic oxygen reduction catalyst loaded with PtNi on defective carbon and elucidated the effect of five-membered ring carbon defect structure and N-doped structure on metal-carrier interaction.

Low temperature synthesis of Cu1−xAl2.5 spinel solid solution as sustained release catalyst for methanol to hydrogen

In order to find a method to synthesize spinel solid solution at low temperature, in this paper, pseudo-boehmite and copper nitrate were used as raw materials, and citric acid was used as accelerator for the first time, the Cu1−xAl2.5 spinel solid solutions were synthesized by ball milling treatment of the solid mixture and then calcined at elevated temperatures. The obtained materials were characterized by X-ray diffraction (XRD), Brunner−Emmett−Teller (BET) measurements, H2-temperature programmed reduction (H2-TPR), infrared (IR) and thermogravimetric methods (TG), and the mechanism of citric acid promoting the synthesis of the spinel solid solution was suggested. The results show that an optimal amount of citric acid can significantly promote the formation of the spinel structure, thus substantially decreasing the synthetic temperature from the above 900 °C–700 °C. At 700 °C, the preparation without the accelerator resulted in small amount of the spinel solid solution, while the use of accelerator gave rise to 82.96% spinel solid solution. Importantly, the Cu1−xAl2.5 spinel solid solution prepared at 700 °C demonstrates the best sustained release catalytic performance, and the catalytic activity reached more than 90% and remained stable within 50 h. The findings of this report might be provide guidance for the solid phase preparation of catalysts at relatively lower temperatures, thus facilitating the commercialization of the sustained release catalyst system.

Large-scale preparation of cobalt niobate/reduced graphene oxide composite materials for high-performance lithium-ion battery anodes

In the field of nanotechnology, the electrodes have received widespread attention as they are a key factor affecting the performance of lithium-ion batteries (LIBs). In this study, a cobalt niobate/reduced graphene oxide composite material (CoNb 2 O 6 /rGO) was prepared using ball-milling-assisted high-temperature calcination and used as an anode for LIBs for the first time. We studied the effects of calcination temperature on the morphology, structure, and electrochemical performance of CoNb 2 O 6 /rGO. The experimental results showed that rGO wrapped around the sphere-like CoNb 2 O 6 particles of nanoscale size. With increasing calcination temperature, the crystallinity of CoNb 2 O 6 increased, while the number of defects in rGO decreased, thus improving the conductivity of CoNb 2 O 6 /rGO. CoNb 2 O 6 exhibits a higher specific capacity—the discharge capacity of CoNb 2 O 6 /rGO-900 is 540.9 mAh/g initially and 457.3 mAh/g after 200 cycles—than that exhibited by graphite (370 mAh/g) at low current densities (0.1 A/g). Furthermore, CoNb 2 O 6 exhibits excellent cyclic stability—the discharge capacity is 130.6 mAh/g initially and 102.8 mAh/g after 4000 cycles, with a capacity retention rate of 78.7%—under a high current density of 5 A/g. The preparation method is a solid-phase technique suitable for large-scale preparation and industrial production. • Cobalt niobate/reduced graphene oxide composite material (CoNb 2 O 6 /rGO) is designed. • The application of CoNb 2 O 6 /rGO as anode of lithium ion battery is studied for the first time. • Graphene can inhibit particle growth, prevent agglomeration and improve electrical conductivity. • The solid-phase preparation method is beneficial to large-scale production and industrial application. • CoNb 2 O 6 /rGO has a higher specific capacity than graphite at low current densities (0.1 A g −1 ). • CoNb 2 O 6 /rGO has excellent cyclic stability under high current density (5 A g −1 ).

Solid-Phase Synthesis of Red Fluorescent Carbon Dots for the Dual-Mode Detection of Hexavalent Chromium and Cell Imaging.

The excellent optical properties and biocompatibility of red fluorescence carbon dots (R-CDs) provide a new approach for the effective analysis of hexavalent chromium Cr(VI) in environmental and biological samples. However, the application of R-CDs is still limited by low yield and unfriendly synthesis route. In this study, we developed a new type of R-CDs based on a simple and green solid-phase preparation strategy. The synthesized R-CDs can emit bright red fluorescence with an emission wavelength of 625 nm and also have an obvious visible light absorption capacity. Furthermore, the absorption and fluorescence signals of the R-CDs aqueous solution are sensitive to Cr(VI), which is reflected in color change and fluorescence quenching. Based on that, a scanometric and fluorescent dual-mode analysis system for the rapid and accurate detection of Cr(VI) was established well within the limit of detection at 80 nM and 9.1 nM, respectively. The proposed methods also possess high specificity and were applied for the detection of Cr(VI) in real water samples. More importantly, the synthesized R-CDs with good biocompatibility were further successfully applied for visualizing intracellular Cr(VI) in Hela cells.

High performance Fe–N–C oxygen reduction electrocatalysts by solid-phase preparation of metal–organic frameworks

Iron-nitrogen-carbon (Fe–N–C) compounds have been regarded as efficient and non-precious metal electrocatalysts for oxygen reduction reaction (ORR). The environmentally friendly preparation of Fe–N–C electrocatalysts is desirable but still challenging. Here, several Fe–N–C catalysts incorporated by ZIF-8 has been simply prepared by solid state reaction method. Fe–N–C containing 2% mole percentage Fe electrocatalysts fired at 900 °C exhibited superior intrinsic activities in oxygen saturated-0.1 M KOH for ORR with half wave potential of 0.831 V (versus RHE), comparable with Pt/C from JM (0.838 V). It also exhibited higher stability than those of Pt–C in alkaline condition. The higher intrinsic ORR activity and remarkable stability can be due to the more dispersed Fe–Nx active sites, which indicate that Fe–N–C by 2% mole percentage Fe electrocatalyst is an excellent alternative electrocatalyst for energy applications.

Synthesis of BaTiO3 nanoparticles by sol-gel assisted solid phase method and its formation mechanism and photocatalytic activity

In this paper, a new sol-gel assisted solid-phase method for the preparation of nano BaTiO3 ceramics is proposed to solve the shortcomings of too high temperature in solid-phase preparation and NO2 pollution produced by sol-gel method. The TiO2 precursor gel is used to encapsulate BaCO3, which can effectively reduce the temperature during calcination. In this study, XRD, FT-IR, XPS, TEM, SEM and TG-DSC were used to explore the structure and evolution of samples at different stages. In addition, the crystallization and growth process of BaTiO3 were further studied. Then the energy band structure and electron hole recombination of different samples were analyzed by UV–Vis and PL spectra. Finally, the photocatalytic activity of different samples was investigated by photolytic water experiment. The results showed that BaTiO3 was initially generated at 600 °C and pure phase BaTiO3 was generated at 800 °C. In the photolytic water experiment, the samples calcined at 700 °C showed the best photocatalytic performance, with a hydrogen production rate of 43.74 μmol/g/h.

A fast and convenient solid phase preparation method for releasing N-glycans from glycoproteins using trypsin- and peptide-N-glycosidase F (PNGase F)-impregnated polyacrylamide gels fabricated in a pipette tip

An efficient deglycosylation process is a key requirement for the identification and characterization of glycosylation during the production and purification of therapeutic antibodies. PNGase F is widely used for the deglycosylation of N-linked glycans. The commonly-used in-solution deglycosylation method is relatively time-consuming and requires several hours up to overnight for complete removal of all N-linked glycans. In order to develop a simple and efficient method for the rapid release of N-linked glycans from glycoproteins, we fabricated trypsin- and PNGase F-impregnated polyacrylamide gels in a commercial 200 μL volume pipette tip. Our enzyme reactor is based on simple photochemical copolymerization of monomers using the following procedure: (1) a pipette tip was filled with a gel solution comprising acrylamide, N,N’-methylene-bis-acrylamide containing PNGase F or trypsin with 2,2-azobis(2-methyl-N-(2-hydroxyethyl) propionamide) as a photocatalytic initiator; and (2) in situ polymerization of gel solution approximately 30 mm from the tip was performed by irradiation with a 365 nm blue LED beam from a distance 10 mm. The fixed enzymes maintained their activities in the polyacrylamide gel and the reaction was completed by 40 iterations of suction and discharge with a pipette (hereafter referred to as manual pipetting times) for 8 min with each enzyme digestion. Capillary electrophoresis (CE) of released glycans labeled with 8-aminopyrene-1,3,6-trisulfonate (APTS) demonstrated quantitative recovery of glycans from selected glycoproteins.

Solid-Phase Preparation of Al-TiO2 for Efficient Separation of Bioderived Product Danshensu

Four kinds of Al-TiO2 solid samples with different Ti/Al ratios of 1 : 0.1, 1 : 0.09, 1 : 0.07, and 1 : 0.05 were synthesized via a solid-phase synthesis method and characterized by XRD, SEM, EDS, BET, and other techniques. The prepared solids were used for separation of the bioderived product danshensu, the content of which was determined by UV spectrophotometry. Moreover, the effects of extract concentration, PH value, adsorption time, and ethanol elution volume were investigated. The results showed that these Al-TiO2 samples had good adsorption and desorption ability. Especially, the solid Al-TiO2 with a Ti/Al ratio of 1 : 0.05 is more suitable for the separation of danshensu, exhibiting a higher adsorption (77.70%) under 2 h adsorption time and pH = 3; meanwhile, the high desorption rate (70.29%）was received under 80% ethanol and the sample concentration of 3.0 mg/mL.

Non-equilibrium thermodynamics and stoichiography in studying solid-phase preparation processes of functional materials

The application of the general principles of the non-equilibrium thermodynamics and stoichiography allows obtaining novel information on the solid-phase transformations happening in multielement and heterophase substances and materials. Without the solid-phase standards, the use of stoichiography allows detecting, identifying and quantitative determining known and unknown crystalline and amorphous phases being of constant or variable composition. For the first time, reliable results concerning evolution of solid products during preparation of the Mo-V-Te-Nb-O catalyst of propane ammoxidation are presented.

Formation of Mn5Ge3 by thermal annealing of evaporated Mn on doped Ge on Si(111)

Mn5Ge3 can be used as a ferromagnetic contact material to fabricate spintronic devices. Here, we show that Mn5Ge3 can be fabricated with a simple germanidation process by evaporating Mn on undoped and doped Ge on Si followed by a thermal annealing step to form the ferromagnetic Mn5Ge3 phase. This solid phase preparation of Mn5Ge3 is a robust process with a minor dependence on the annealing parameters. The formation of Mn5Ge3 can be realized using undoped as well as highly doped p-Ge and n-Ge with different doping levels. The interface of Mn5Ge3 is atomically sharp which leads to very low contact resistivities < 1 × 10−7 Ω cm2.

Improved Ferroelectric and Ferromagnetic Properties of 1 − xBiFeO3-xBaTiO3 Ceramics

This paper introduces the solid-phase preparation of bismuth ferrite-based multiferroic ceramics (1 − x BiFeO3-x BaTiO3). After the Ba and Ti doping, it can be observed from the XRD pattern that the crystal structure of the sample changes obviously. From the picture obtained from the SEM test, the grain size of the doped samples was significantly reduced. Pure BiFeO3 (BFO) showed a large leakage current, and in the leakage current test, we found that the leakage current of Ba, Ti-doped samples decreased significantly, which may be related to doping, leading to oxygen vacancy reduction. From the magnetization hysteresis loops, we can see that the ferromagnetism of the doped samples was significantly improved compared to pure BFO, because Ba, Ti doping destroys the G-type antiferromagnetic sequence of pure BFO, thereby enhancing the ferromagnetic properties.

High reactive sulphide chemically supported on silica surface to prepare functional nanoparticle

A solid-phase preparation method was applied to obtain a novel, green and effective functional nanoparticle, silica-supported sulfur monochloride (silica-s-S2Cl2), by the chemical reaction between chlorine atom and silicon hydroxyl on the silica surface. Through this chemical reaction, silica surface supported with high content of sulfur, and the functional nanoparticles can not only vulcanize the rubber instead of sulfur or other vulcanizing agent with high performance, but also improve the filler-rubber interaction as a modifier due to the improved modification effect. 29Si NMR, Raman spectroscopy, Element analysis and TGA confirm that the sulfur monochloride is chemically bonded on the silica surface. Cure properties measurement, morphology of filler dispersion, mechanical properties measurement, immobilized polymer layer and oxidation induction time increment together show that the novel vulcanizing agent silica-s-S2Cl2 instead of sulfur in rubber vulcanization gives rise to significant improvement in the crosslinking density and the interfacial adhesion between silica particles and the rubber matrix, which is on account of the promoted vulcanizing on the functional silica nanoparticles surface with the supported sulfur.

The Preparation of Cu - doped Ca3Co4O9 Thermoelectric Materials

In this paper, CaCO3, CoO, CuO as raw materials, using solid phase preparation of Ca3Co4O9-based thermoelectric materials doping Cu. The Ca3Co4O9-based thermoelectric material intermediates were prepared according to the stoichiometric ratio x=0.01, and the sintered crystals were prepared by using muffle furnace under different temperature setting conditions. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were used to analyze the crystallinity and morphology of the samples after sintering. The results show that the crystallinity of Ca3Co4O9-based thermoelectric materials is best when sintered at 800-850°C, and the crystallinity of samples sintered at 850°C is better than that at 800°C, The diffraction intensity ratio is stronger than 800°C. Continue to raise the temperature, Ca3Co4O9-based thermoelectric materials phase transition to Ca3Co2O6-based thermoelectric materials, When the sintering temperature is 1000°C, the product is Cu-doped Ca3Co2O6-based thermoelectric materials.

Selective conversion of methane to aromatic hydrocarbons on large crystallite zeolite catalysts with mesoporous structure

Large crystallite mesoporous MFI (ZSM-5) zeolite was synthesized by using carbon nano-powder as a secondary template. The surface properties, morphological and phase composition of the synthesized material and of the commercial ZSM-5 (Zeolyst) zeolite were studied by nitrogen porosimetry, XRD and scanning electron microscopy. The results showed that the volume of mesopores volume increases with development of a secondary mesoporosity in the structure of zeolite. The obtained zeolite supports were used to prepare molybdenum-containing catalysts for the methane aromatization by solid phase preparation technique. Based on the XPS data, molybdenum particles in these catalysts are characterized by more uniform size distribution. The formation of a secondary pore structure restrains the carbon deposit formation as well as increases the methane conversion and the yield of the aromatic compounds.

Silver-Doped Calcium Phosphate Bone Cements with Antibacterial Properties.

Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO3)3 was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content.

Solid-phase synthesis of fusaricidin/LI-F class of cyclic lipopeptides: Guanidinylation of resin-bound peptidyl amines.

Fusaricidins/LI-Fs and related cyclic lipopeptides represent an interesting new class of antibacterial peptides with the potential to meet the challenge of antibiotic resistance in bacteria. Our previous study (Bionda et al. ChemMedChem 2012, 7, 871-882) revealed the significance of the guanidinium group located at the termini of the lipidic tails of these cyclic lipopeptides for their antibacterial activities. Therefore, devising a synthetic strategy that will allow incorporation of guanidinium functionality into their structure is of particular practical importance. Since appropriately protected guanidino fatty acid building blocks are not commercially available, our strategy toward guanidinylated fusaricidin/LI-F analogs include solid-phase synthesis of a cyclic lipopeptide precursor possessing a lipidic tail with a terminal amino group followed by its conversion into corresponding guanidine. To find the optimal method for this conversion, we have examined commonly used guanidinylation reagents under the conditions compatible with standard solid-phase peptide synthesis. Described experimental results demonstrated superiority of N,N'-di-Boc-N″-triflylguanidine in solid-phase preparation of fusaricidin/LI-F class of cyclic lipopeptides. The triflylguanidine reagent gave a single monoguanidinylated product in excellent yield independently of the type of solid-support.

Influence of Liquid or Solid Phase Preparation of Cationic Hemicelluloses on Physical Properties of Paper

Cationizations of galactomannan- and xylan-type hemicelluloses were performed in a solid state, with 2,3-epoxypropyltrimethylammonium chloride (ETA) as the cationic reagent under alkaline conditions. By this method, the reaction efficiency was significantly increased for all hemicellulose types, up to 90% in the case of xylan. The consumption of reagents was reduced by a factor of ten when compared to the reaction in liquid phase, while comparable values of the degree of substitution (DS) were obtained. By reducing the number of purification steps, the consumption of solvents was limited, and high mass yields were preserved. By all aspects, this method constitutes an economical and environmental gain for the cationization reaction of hemicelluloses. Native hemicelluloses and their cationic derivatives were tested as additives to the pulp slurry in order to increase the dry strength of the paper formed. The cationization of hemicelluloses had a beneficial effect on the mechanical properties of paper, with a supplementary gain of properties compared to the unmodified polysaccharides. Cationic derivatives of a DS 0.3 gave the best results for both polysaccharides, with the galactomannan-type being more efficient than the xylan-type with a 90% increase of the burst index.

Simple and Efficient Solid-Phase Preparation of Azido-peptides

A shelf-stable and easily prepared diazotransfer reagent, imidazole-1-sulfonyl azide hydrochloride, was used to transform the N-terminus of a model peptide on solid phase into an azide moiety. It is demonstrated that this conversion was accomplished within 30 min with high efficiency under aqueous conditions on a NovaPEG resin or in DMF on polystyrene beads.

Samplers for VOCs in air based on cyclodextrin–silica hybrid microporous solid phases

Samplers for VOCs in air based on cyclodextrin-silica hybrid microporous solid phases are proposed. The solid phase preparation is very easy and inexpensive. Proposed samplers compared with other solid phases present the advantages of a wider range of operative conditions for VOCs desorption. Samplers are tested based on results for the determination of benzene, toluene, ethylbenzene and o-xylene, m-xylene and p-xylene (BTEX) in air. Operational parameters are optimized and quantitative recovery is obtained using a solid phase from 2-hydroxypropyl-β-cyclodextrin and acetonitrile as the extraction solvent. The recoveries obtained are 89 ± 4%, 90 ± 6%, 91 ± 2%, 87.0 ± 0.9%, 88 ± 4%, and 88 ± 4% for benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, respectively. Moreover results indicate a good reproducibility with a coefficient of variation below 6% and no significant difference between the reproducibility intra-synthesis and inter-synthesis. The proposed procedure has been applied to the determination of BTEX in several contaminated air samples and compared with results provided by a reference method.