Simultaneous determination of sulfite, sulfate, and hydroxymethanesulfonate in atmospheric waters by ion-pair HPLC technique

A reversed-phase ion-pair HPLC with indirect photometric detection for the simultaneous determination of sulfite, sulfate, hydroxymethanesulfonate (HMS), and other inorganic anions in atmospheric water has been developed. Separations were accomplished in less than 10 min in a cetylpyridinium-coated C₁₈ column with 0.5 mM potassium hydrogen phthalate-0.015% triethanolamine-3% methanol at pH 7.9 as mobile phase. Quantitation was carried out by the peak area method, with detection limits in the pmol range. UV light absorption responses were linear over a wide concentration range from several hundred μmoles to the detection limits of each anion. The application of the method provides a rapid and efficient technique for the quantitative determination of sulfur and other inorganic species in atmospheric liquids.     

Calycilactone A, a novel hexacyclic alkaloid from Daphniphyllum calycillum

A novel Daphniphyllum alkaloid with a rearranged fused-hexacyclic ring system, calycilactone A, was isolated from the leaves of Daphniphyllum calycillum (Daphniphyllaceae), and the structure and relative stereochemistry of the new compound were elucidated on the basis of spectroscopic data.     

硫化物的生物氧化成手性亚砜

描述了硫化物不对称生物氧化成手性亚砜, 主要为氯过氧化物酶、环己酮单氧酶催化有机硫化物氧化成具有光学活性的亚砜的两条酶促反应途径.     

Agonist–PPARγ interactions: Molecular modeling study with docking approach

Docking simulation of 18 agonists with the ligand binding pocket (LBP) of PPARγ has been performed. The binding conformations and binding affinities of these agonists were obtained by use of the flexible docking protocol FlexX. Test compound calculations indicated that FlexX can reproduce the binding conformation of the crystal structure (root mean square deviation = 1.43 Å); moreover, the predicted binding affinities correlate well with the activities of these agonists. The interaction model and pharmacophore of PPARγ agonists were derived and the difference in biologic activities of these agonists can be well explained. The PPARγ agonists must have both polar head and the hydrophobic tail, which form hydrogen bonds and hydrophobic contacts with hydrophilic and hydrophobic regions of the LBP of PPARγ, respectively. In addition, a suitable linker is also necessary. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 405–410, 2003     

氯化镧对自由基的影响研究

通过检测肠组织丙二醛(MDA)、超氧化物歧化酶(SOD)、髓过氧化物酶(MPO)、过氧化氢酶(CAT)量,表明氯化镧在大鼠伤后1 d提高肠道SOD和CAT的活性、伤后3 d提高SOD的活性、伤后5 d降低MPO的活性,使MDA的量产生减少.     

LBL分子沉积法制备葡萄糖氧化酶电极

采用以静电力为主的逐层分子交替沉积技术制备葡萄糖氧化酶（GOD）电极.通过带有正电荷的聚二甲基二烯丙基铵盐酸盐（PDDA）和带有负电荷的GOD交替沉积在修饰有3-巯基-1-丙基磺酸钠（MPS）的金电极表面.以甲酸二茂铁为电子媒介体,用循环伏安法检测GOD电极对葡萄糖的响应.结果表明,当GOD电极组装层数小于4时,电流响应随着层数的增加而增大,超过4层时电流响应减小.其中4层GOD修饰电极的线性范围为0.55～6.63 mmol•L－1,当pH为7.0时,响应最大.同时电极的检测重现性能良好,相对标准偏差为2.4％.     

X射线荧光光谱法在稀土元素分析中的应用

本文研究了Ｘ射线荧光光谱在混合稀土氧化物和高纯稀土氧化物分析中的应用，并探讨了在常量分析中影响分析准确度和精密度的主要因素；样品及标样制备，基体效应校正方法在痕量分析中降低检测限的方法，选择最佳测量条件，降低背景，与分离富集手段相结合，取得满意的结果。     

Cooperation of reducing species for NO reduction over Ag/Al2O3 under oxidizing conditions

Summary The cooperation effect of reducing species for selective reduction of NO over Ag/Al₂O₃ has been investigated in the presence of excess oxygen. When the combinations of propene or propane and ethanol or methanol were used as reducing agents, NO reduction took place over a wider temperature range, compared with a single hydrocarbon as reducing agent.     

Bis­(ethyl­enedi­amine)copper(II) bis(O,O′‐diethyl di­thio­phosphate)

In the structure of the title compound, [Cu^II­(en)₂][(EtO)₂P(S)S]₂ (en is ethyl­ene­di­amine) or [Cu(C₂H₈N₂)₂](C₄H₁₀O₂PS₂)₂, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethyl­enedi­amine mol­ecules. The diethyl di­thio­phosphate moieties, (EtO)₂P(S)S^?, act as counter‐anions.     

玻璃载体表面脱氧核糖核酸的固定及其化学发光检测

用硅烷化偶联剂把ＤＮＡ直接共价固定在载玻片表面，将辣根过氧化物酶标记的探针与之进行核酸杂交，杂交后用增强的化学发光检测。方法的检出限为７５ｐｇ。研究了ＤＮＡ分子固定在玻璃载体表面的各种条件，并建立了在玻璃载体表面进行核酸杂交的体系，为研究光纤ＤＮＡ生物传感器打下了基础。