Electrochemical behavior of p-dihydroxybenzene in DMPC biomimetic membrane

在金电极上构筑一种双肉豆蔻磷脂酰胆碱(DMPC)仿生浇铸膜。经椭圆偏振仪和电化学方法测量证实, DMPC仿生膜是较为致密的多层膜,同时对苯二酚能够透过DMPC仿生膜到达金电极表面进行氧化反应。结果表明,对苯二酚不仅可在脂质膜中进行电子转移,而且是一种重要的生物分子。反应在仿生环境内进行,也为研究生物小分子在真正的生物体内的反应提供有益的帮助。本文探讨对苯二酚在仿生膜修饰电极上的电化学行为,为生物膜中的电子转移过程提供了十分重要的信息。The casting method to form dimyristoyl phosphatidyl choline(DMPC)mimetic biomembrane on an Au electrode is proposed.The results of ellipsometer and electrochemical methods confirmed that the film is a compact membrane that can block the electron transferring process,p-Dihydroxybenzene can reach the electrode surface and occur redox reactions by passing through transient defects in individual bilayers.Such defects occur in biomembranes and are accentuated by relatively small electric fields.The electrochemical behavior of p-dihydroxybenzene in this membrane was also investigated,p-Dihydroxybenzene is biologically important molecule because of its function of transferring electrons in lipid layers.This reaction occur in the bionic environment,which provide the useful help to study the real reaction of small molecules in the biological organisms.Studies on the electrochemical behavior of p-dihydroxybenzene in the DMPC biomimetic membrane provide useful information for elucidating biological electron transfer processes concerning lipid layers.国家自然科学基金项目(20833005,20873116)。~

Adsorption and Oxidation of L-Lysine on Nanometer Scale Au Film Electrodes in Alkaline Solution

采用原位红外反射光谱(in situFTIRS)和循环伏安法(CV)研究了碱性介质中L-赖氨酸在纳米金膜电极(nm-Au/GC)上的解离吸附和氧化过程.研究结果表明,在碱性溶液中以阴离子形式存在的赖氨酸[-OOC—CH—NH2—(CH2)4—NH2]在低电位区间(-0.95~-0.80 V,vs.SCE)发生部分解离,生成AuCN-物种(约2110 cm-1),同时赖氨酸阴离子的羧基侧还可通过两个氧原子与金电极表面相互作用.随着电位的升高,吸附态CN-氧化产生NCO-,OCN-和AuCN,其对应的红外吸收峰分别位于2254,2168和2226 cm-1附近.Amino acids are the building blocks of peptides and proteins.An amino acid molecule contains multi-functional groups such as —COOH,—NH2,—OH and —CHx,which leads to the amino acids to be used often as model reagents in surface electrochemistry and electrocatalysis,for the purpose of obtaining information about the interaction of different functional groups with electrocatalyst surfaces and the role of these functional groups in electrocatalysis of small organic fuels.Up to now,the reaction mechanism of amino acid electrooxidation is still far to be well understood.In this study,adsorption and oxidation of L-lysine on electrodes of nanometer scale thin film of gold in alkaline solutions were investigated using in situ FTIR reflection spectroscopy and electrochemical methods.The FTIRS result demonstrate that the dissociative adsorption of lysine on Au surface can occur in a low potential region,and the chemisorbed species were identified as adsorbed CN-species(cyanide,2110 cm-1).Another reversibly(or loosely) adsorbed species may be the deprotonated amino acids,which were bound to the surface by both oxygen atoms of carboxyl group.When electrode potential is higher than 0.1 V,the adsorbed CN-can be oxidized to NCO-(2254 cm-1);when electrode potential is above 0.3 V,OCN-(cyanate,2168 cm-1) appeared as oxidative species;and when the potential is increased further up to 0.5 V,another further oxidative species,the AuCN species(gold cyanide,2226 cm-1) appeared.This study is of importance in understanding the interaction between amino acids and Au film electrodes.国家自然科学基金(批准号:20673091,20423002)资

in situ FTIR Spectroscopic Studies of Adsorption and Oxidation of L-Serine on Pt Electrodes in Neutral Solutions

运用电化学循环伏安(CV)和原位红外反射光谱(In SITufTIrS)研究了中性介质中l-丝氨酸在PT电极上的解离吸附和氧化过程.结果表明,在中性溶液中,以两性离子形式存在的丝氨酸可以在很低的电位下(-0.6 V,VS.SCE)在PT电极表面发生解离吸附,生成强吸物种一氧化碳(COl)、(COb)和氰负离子(Cn-).研究结果还表明,当电位低于0.7 V(VS.SCE)时,Cn-能稳定存在于电极表面,抑制丝氨酸的进一步反应.在更高电位时则主要为丝氨酸分子的氧化过程.The dissociative adsorption and oxidation of L-serine on platinum electrode in neutral solutions were studied via in situ FTIR reflection spectroscopy and electrochemical methods.The FTIRS results demonstrate that the serine can be easily dissociated on Pt surface at potentials below-0.6 V(vs.SCE) to form cyanide(--2100 cm-1) and carbon monoxide(COL,--2034 cm-1;COB,--1870 cm-1).The observation of an absorption band at 2343 cm-1 is ascribed to CO2,which implies the cleavage of the C—C bond during the dissociative adsorption of serine.It has determined that the cyanide was strongly adsorbed on electrode surface in a wide potential region below 0.7 V(vs.SCE) and inhibited the oxidation of serine.At higher potentials,the serine molecules could be oxidized directly to yield the main product CO2 species.As the pH decreased in the spectroelectrochemical cell during serine reactions,the acidic serine species also detected.The present study revealed the interaction of serine with Pt electrode surface,and suggested a possible reaction mechanism of serine on Pt electrode surface in neutral solutions.国家自然科学基金(批准号:20673091;20833005)资

飞行质谱鉴定临床分离真菌准确度的Meta分析

目的基于循证医学系统性评价飞行质谱鉴定临床分离真菌的准确度,并与常规方法准确度进行比较。方法检索主要英文数据库PubMed、Cochrane、Web of Science,以及中文数据库CBM、万方、维普、知网数...甘肃省卫生行业科研计划(No.GSWST2012-04

Adsorption and oxidation of L-lysine on nanometer scale an film electrodes in alkaline solution

Amino acids are the building blocks of peptides and proteins. An amino acid molecule contains multi-functional groups such as -COOH, -NH2, -OH and -CHx, which leads to the amino acids to be used often as model reagents in surface electrochemistry and electrocatalysis, for the purpose of obtaining information about the interaction of different functional groups with electrocatalyst surfaces and the role of these functional groups in electrocatalysis of small organic fuels. Up to now, the reaction mechanism of amino acid electrooxidation is still far to be well understood. In this study, adsorption and oxidation of L-lysine on electrodes, of nanometer scale thin film of gold in alkaline solutions were investigated using in situ FTIR reflection spectroscopy and electrochemical methods. The FTIRS result demonstrate that the dissociative adsorption of lysine on An surface can occur in a low potential region, and the chemisorbed species were identified as adsorbed CN- species(cyanide, 2110 cm(-1)). Another reversibly( or loosely) adsorbed species may be the deprotonaled amino acids, which were bound to the surface by both oxygen atoms of carboxyl group. When electrode potential is higher than 0.1 V, the adsorbed CN- can be oxidized to NCO- (2254 cm(-1)); when electrode potential is above 0.3 V, OCN- (cyanate, 2168 cm(-1)) appeared as oxidative species; and when the potential is increased further up to 0.5 V, another further oxidative species, the AuCN species( gold cyanide, 2226 cm(-1)) appeared. This study is of importance in understanding the interaction between amino acids and Au film electrodes