imFASP: An integrated approach combining in-situ filter-aided sample pretreatment with microwave-assisted protein digestion for fast and efficient proteome sample preparation

An integrated sample preparation method, termed “imFASP”, which combined in-situ filter-aided sample pretreatment and microwave-assisted trypsin digestion, was developed for preparation of microgram and even nanogram amounts of complex protein samples with high efficiency in 1 h. For imFASP method, proteins dissolved in 8 M urea were loaded onto a filter device with molecular weight cut off (MWCO) as 10 kDa, followed by in-situ protein preconcentration, denaturation, reduction, alkylation, and microwave-assisted tryptic digestion. Compared with traditional in-solution sample preparation method, imFASP method generated more protein and peptide identifications (IDs) from preparation of 45 μg Escherichia coli protein sample due to the higher efficiency, and the sample preparation throughput was significantly improved by 14 times (1 h vs. 15 h). More importantly, when the starting amounts of E. coli cell lysate decreased to nanogram level (50–500 ng), the protein and peptide identified by imFASP method were improved at least 30% and 44%, compared with traditional in-solution preparation method, suggesting dramatically higher peptide recovery of imFASP method for trace amounts of complex proteome samples. All these results demonstrate that the imFASP method developed here is of high potential for high efficient and high throughput preparation of trace amounts of complex proteome samples.     

Highly efficient microwave-accelerated preparation of β-ketoimines

We present here a new and efficient methodology for the β-ketoimine ligand with microwave heating system. The new method showed faster reaction rates, higher yields, and selectivities of the desired compounds in the absence of solvents.     

Highly efficient template-based preparation of shape-persistent macrocyclics

The synthesis of shape-persistent macrocycles via oxidative dimerization or trimerization of rigid bisacetylenes (via Glaser coupling) is described. To enhance the yield of the desired target structures, the precursors are temporarily covalently bound to a template resulting in an intramolecular coupling instead of an intermolecular coupling. As a result, product yields up to over 90 % are observed.     

Highly efficient methods for the preparation of shape-persistent macrocyclics

It has been about 25 years since Staab prepared a hexameric phenyl–ethynyl macrocycle by the statistical cyclization of the copper salt of m-iodo-phenylacetylene in 4.6% yield. Since that time, different methodologies have been investigated that allow not only the preparation of selectively functionalized structures, but also their formation in high yields. The repetitive formation of precursors followed by an intramolecular cyclization is only one approach to these structures. Alternatives include the use of covalently or noncovalently bound templates, as well as cyclization under thermodynamic control. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2685–2698, 1999     

Highly efficient adsorbing noble metal ions by 3,4-dihydroxycinnamic acid-modified activated carbon

A method was established for the preconcentration of trace Au(III), Pd(II) and Pt(IV) by activated carbon modified with 3,4-dihydroxycinnamic acid. The separation and preconcentration conditions of analytes were investigated, such as effects of pH, the contacting time, the sample ?ow rate and volume, the elution condition and the interfering ions. At a pH of 1.0, the maximum static sorption capacity of the sorbent was found to be 374.8, 96.6 and 137.5 mg g^?1 for Au(III), Pd(II) and Pt(IV), respectively. The adsorbed metal ions were effectively eluted with 2.0 mL of 4% thiourea in 0.5 M HCl solution and determined by inductively coupled plasma optical emission spectrometry. The detection limit (3σ) of this method defined by IUPAC was found to be 0.12, 0.18 and 0.32 ?g L^?1 for Au(III), Pd(II) and Pt(IV), respectively. The relative standard deviation (RSD) was lower than 3.0% (n = 8) towards standard solutions. The method has been validated by analysing certified reference materials and successfully applied to the determination of trace Au(III), Pd(II) and Pt(IV) in road sediments samples.     

Highly efficient chemical fixations of carbon dioxide and carbon disulfide by cycloaddition to aziridine under atmospheric pressure

Cycloaddition of aziridine with carbon dioxide was successfully catalyzed by alkali metal halide or tetraalkylammonium halide to give the corresponding 5-membered cyclic urethane, 1,3-oxazolidin-2-one, selectively. The reaction can be performed at ambient temperature under atmospheric pressure. Analoguous reaction of aziridine with carbon disulfide also successfully gave the corresponding 5-membered cyclic dithiourethane, 1,3-thioxazolidine-2-thione.     

FeCo alloy@N-doped graphitized carbon as an efficient cocatalyst for enhanced photocatalytic H_2 evolution by inducing accelerated charge transfer

Cocatalysts play important roles in improving the activity and stability of most photocatalysts.It is of great significance to develop economical,efficient and stable cocatalysts.Herein,using Na2CoFe(CN)6 complex as precursor,a novel noble-metal-free FeCo@NGC cocatalyst(nano-FeCo alloy@N-doped graphitized carbon) is fabricated by a simple pyrolysis method.Coupling with g-C3 N4, the optimal FeCo@NGC/g-C3N4 receives a boosted visible light driven photocatalytic H2 evolution rate of 42.2 μmol h-1, which is even higher than that of 1.0 wt% Pt modified g-C3N4 photocatalyst.Based on the results of density functional theory(DFT) calculations and practical experiment measurements,such outstanding photocatalytic performance of FeCo@NGC/g-C3N4 is mainly attributed to two aspects.One is the accelerated charge transfer behavior,induced by a photogene rated electrons secondary transfer performance on the surface of FeCo alloy nanoparticles.The other is related to the adjustment of H adsorption energy(approaching the standard hydrogen electrode potential) by the presence of external NGC thin layer.Both factors play key roles in the H2 evolution reaction.Such outstanding performance highlights an enormous potential of developing noble-metal-free bimetallic nano-alloy as inexpensive and efficient cocatalysts for solar applications.     

Highly efficient preparation of aryl beta-diketo acids with tert-butyl methyl oxalate

An improved and efficient oxalylation of aryl methyl ketones was accomplished with tert-butyl methyl oxalate. This is the key step in constructing the pharmacophore of aryl beta-diketo acids, which represent a promising new class of HIV-1 integrase inhibitors. Structurally diverse aryl beta-diketo acids, including bisdiketo acids, can be prepared rapidly in impressive yields under mild conditions with this method. Advantages over conventional methods with dimethyl (or diethyl) oxalate were observed in both yield and reaction time.     

A soluble hybrid material combining carbon nanohorns and C60

A soluble hybrid nanomaterial that combines fullerenes and carbon nanohorns (CNHs) has been prepared and fully characterized. Electrochemical investigations revealed that the CNHs modify the electron accepting ability of C(60) in the hybrid material.     

Comparison of physical and gas chromatographic properties of sterling FT and carbopack C graphitized carbon blacks

A comparison of Sterling FT, a graphitized carbon black used widely in ad- sorption and gas chromatography, and Carbopack C, a commercially available graphitized carbon black, was made in terms of retention parameters, heats of adsorption and their behaviour at various coating percentages.

The effects induced by hydrogen treatment at high temperature are compared, and it is shown that graphs of the heat of adsorption versus percentage of liquid phase added are very useful in understanding the difference in the surface properties of the two materials. The advantages of the two carbon blacks in practical gas chromato- graphy are discussed.     

Highly efficient route for enantioselective preparation of chlorohydrins via dynamic kinetic resolution

Dynamic kinetic resolution (DKR) of various aromatic chlorohydrins with the use of Pseudomonas cepacia lipase (PS-C "Amano" II) and ruthenium catalyst 1 afforded chlorohydrin acetates in high yields and high enantiomeric excesses. These optically pure chlorohydrin acetates are useful synthetic intermediates and can be transformed to a range of important chiral compounds.     

Extended SIMS capabilities by sample preparation

Summary Two situations are referred to, in which the application of SIMS is limited by sample- and instrument-related effects, namely the analysis close to sample edges and the depth profiling over a high dynamic range (in excess of 5 orders of magnitude). Methods of sample preparation are described which result in a pronounced extension of the range of applicability of SIMS in these situations. In terms of detection sensitivity, on boron-implanted silicon between one and two orders of magnitude may be gained as compared to non-preparative direct measurements.     

Synthesis and surface photochemistry of graphitized carbon quantum dots

Graphitized carbon quantum dots (CQDs) were synthesized by a simple hydrothermal process with cetyltrimethylammonium bromide (CTAB) as the starting material and nitric acid as surface oxidant. The photoluminescent quantum yield (QY) of CQDs could be greatly enhanced through surface esterification with glycol. Based on the structure characterization, we proposed that the CQDs consisted of the stack of graphene sheets sized several nanometers and their excitation-dependent photoluminescence (PL) should be attributed to the n→π* transition of CO bond of surface carboxylic groups. And the PL of CQDs was obviously enhanced by the esterification of carboxylic groups, possibly due to the increase of the molecular coplanarity or the rigidity.