Capillary isoelectric focusing in pseudo-closed channel coupled to matrix assisted laser desorption/ionization mass spectrometry for protein analysis

Capillary isoelectric focusing (CIEF) was performed in pseudo-closed channel to separate proteins on a plastic chip. Pseudo-closed channel provided a novel way to couple protein separation by CIEF to MALDI mass spectrometry without eluting the focused proteins.     

SIA spotlight on Asia

There has been rapid development in science and technology in Asia in recent decades, including in the fields of surface and interface sciences. This has been facilitated by the sustained economic growth in the region, especially the growth of the semiconductor, electronic, chemical, coating and biomedical industries. Accompanying this growth is the increased use of more sophisticated analytical techniques, especially in the field of surface and interface analysis. This article reviews a selection of papers from Asia, published in major international journals in the last two years. Short reviews of each paper are presented in three sections: (i) Characterization and techniques, (ii) Materials and processing and (iii) Nanoscience and nanotechnology. Copyright © 2007 John Wiley & Sons, Ltd.     

Room-temperature heterogeneous hydroxylation of phenol with hydrogen peroxide over Fe2+, Co2+ ion-exchanged Na beta zeolite

Ion-exchanged Na beta zeolite with Fe2+ and Co2+ cations shows high catalytic activity at room temperature in phenol hydroxylation with H2O2, where the conversion of phenol is ca. 21% and the selectivity of benzoquinone is below 3% at a molar ratio of phenol to H2O2 of 3 in the starting aqueous reaction medium.     

High performance liquid chromatographic determination of aluminium in natural waters in the form of its lumogallion chelate

A high performance liquid chromatographic method for the determination of ultra trace amount of aluminium in natural waters has been developed using lumogallion as a precolumn reagent for fluorimetric detection. The highly fluorescent Al-lumogallion chelate (lambda(ex) 500 nm, lambda(em) 574 nm) was separated on a LiChrosorb RP 18 column with an eluent containing 3:7 acetonitrile/0.02M potassium hydrogen phthalate buffer (pH 4.7) containing 10(-5)M lumogallion. The proposed system provides a simple, quick, selective and sensitive method for the determination of ultra-trace amount of aluminium in water samples. The detection limit defined as three times the standard deviation of the blank signal, was 0.05 mug/l. in water samples for 100 mul injection. The tolerance limits were 5 mg/l. for Fe(III) and F(-) and over 10 mg/l. for other foreign ions. The sensitivity of the method was independent of salinity. This method had been used for the direct determination of aluminium in both tap and coastal sea-waters without any preconcentration steps.     

Synthetic, X-ray structural and protonation studies of CpCr(CO)2SPy and CpCr(CO)2SPym (SPy = C5H4NS, SPym = C4H3N2S)

The facile reaction of [CpCr(CO)₃]₂ (Cp = η⁵-C₅H₅) (1) with one mole equivalent of 2,2′-dithiodipyridine ((C₅H₄NS)₂(SPy)₂) at ambient temperature led to the isolation of dark brown crystalline solids of CpCr(CO)₂(η²-SPy) (2) in ca. 72% yield. 2 undergoes quantitative conversion to CpCrCl₂(η¹-SPyH) (3) with HCl. The reaction 1 with one mole equivalent of 2-mercaptopyrimidine (C₄H₃N₂SHHSPym) at ambient temperature led to the isolation of reddish-brown crystalline solids of CpCr(CO)₂(η²-SPym) (4) and green solids of CpCr(CO)₃H (5) in yields of ca. 42% and 46%, respectively. Reaction of 4 with HCl and subsequent workup in acetonitrile resulted in the cleavage of the thiolate ligand, giving the 15-electron chromium(III) species CpCrCl₂(CH₃CN) (6) and free 2-mercaptopyrimidine. The complexes 2-4 have been determined by single X-ray diffraction analysis.     

Lactic acid production through cell-recycle repeated-batch bioreactor

The effect of various nitrogen sources on cell growth and lactic acid production was investigated. The most effective nitrogen source was yeast extract; more yeast extract gave higher cell growth and lactic acid productivity. Yeast extract dosage and cell growth were proportional up to a yeast extract concentration of 30 g/L, and lactic acid productivity was linearly correlated up to a yeast extract dosage of 25 g/L. However, increasing the yeast extract content raises the total production cost of lactic acid. Therefore, we attempted to find the optimum yeast extract dosage for a repeated-batch operation with cell recycling. The results show that when using Enterococcus faecalis RKY1 only 26% of the yeast extract dosage for a conventional batch fermentation was sufficient to produce the same amount of lactic acid, whereas the lactic acid concentration in the product stream (92–94 g/L) and lactic acid productivity (6.03–6.20 g/[L·h]) were similar to those of a batch operation. Furthermore, long-term stability was established.     

Nanoparticle dispersion on reconstructed carbon nanomeshes

A nanoporous template which can be used for the preparation of monodispersed metal nanoparticles can have wide-ranging applications in the catalyzed growth of single-walled nanotubes, as well as the preparation of energetic, nanostructured ferromagnetic particle arrays. Here, we found that a honeycomb-like carbon nanomesh with periodically arranged pores of approximately 2-nm dimension could be fabricated on the reconstructed 6H-SiC(0001) surface. The carbon nanomesh arises from the periodic arrangement of segregated carbon clusters on the 6H-SiC surface to form a highly regular, nanoporous film. The carbon nanomesh can be dynamically structured to control the periodicity and depth of the pores by annealing in a vacuum. We evaporated cobalt on the surface of the nanomesh and investigated the diffusion and agglomeration behavior of cobalt clusters using in situ scanning tunneling microscopy. It is found that monodispersed Co nanoclusters that resist aggregation up to a temperature of 500 degrees C can be fabricated on this template.