Daowu Yang

Mesoporous silica hollow sphere (MSHS) for the bioelectrochemistry of horseradish peroxidase

In this work, novel mesoporous silica hollow spheres (MSHS) were chosen as an immobilization matrix, to construct a mediator-free third-generation HRP biosensor. UV-vis spectroscopy revealed that horseradish peroxidase (HRP) entrapped in MSHS could retain its native structure. FTIR spectroscopy and nitrogen adsorption-desorption isotherms indicated that HRP are intercalated into the mesopores. The direct electron transfer of HRP entrapped in MSHS was observed. A pair of stable and well-defined redox peaks of HRP with a formal potential of about -0.150 V (vs. Ag/AgCl) in 0.1M pH 7.0 phosphate-buffered solution (PBS) were obtained. The biosensor exhibited a fast amperometric response to H(2)O(2) with a linear range of 3.9 x 10(-6) to 1.4 x 10(-4)M (R=0.997, N=20). The detection limit was 1.2 x 10(-6)M based S/N=3.

Triaqua(2-{[(E)-5-formyl-2-oxidobenzyl­idene]amino}ethanesulfonato)cobalt(II) dihydrate

The title compound, [Co(C10H9NO5S)(H2O)3]·2H2O, is a cobalt–Schiff base complex derived from taurine. There are two complex molecules and four solvent water molecules in the asymmetric unit. The central Co atom is six coordinated by two O atoms and one N atom of the ligand and three O atoms of water molecules, forming a slightly distorted octahedral geometry. The crystal structure is stabilized by several O—H⋯O hydrogen bonds.

Corrosion Behaviors on Polycrystalline Gold Substrates in Self‐Assembled Processes of Alkanethiol Monolayers

Abstract The adsorption response behaviors with n‐alkanethiol self‐assembled monolayers (SAMs) formed on the surface of polycrystalline gold grains have been investigated in nitrogen and oxygen saturated tetrahydrofuran (THF) solutions by using in situ quartz crystal microbalance (QCM) and atomic force microscopy (AFM). Comparing with frequency‐decreased process in the nitrogen saturated solution, the response behavior shows a frequency increased process in the oxygen saturated solution, indicating that the gold corrosion is accompanied to occur in the self‐assembled process of organothiol that is due to the thiol induction and oxygen oxidation. In the presence of thiol and oxygen, the corrosion effect is stronger than the adsorption effect of organothiols, such as n‐dodecanethiol molecules on gold, which causes gold loss from the QCM surface, made evident from the observation of many corrosive defects or holes produced on the surface of gold grains by AFM image. Furthermore, the kinetic behavior on the corrosion rate of gold dissolved in the organothiol solution with time has been examined. The maximum quantity of gold dissolved into the thiol solution can be calculated to be approximately 8.7×1013 Au atoms cm−2 from the QCM data during the strong corrosion process in the oxygen saturated solution. The corresponding gold corrosion rates at fast and slow stages can be estimated to be 9.2×1011 and 5.4×1010 Au atoms cm−2 s−1, respectively. The surface coverage of SAMs increases from 3.2 to 31.2%, while the gold loss decreases from about 6 to 0.6% of an Au monolayer in the self‐assembled process.