反相高效液相色谱法快速测定长春花中4种生物碱

采用反相高效液相色谱法同时分离测定4种长春花吲哚类生物碱。以水：二乙胺=986：14，用磷酸调节pH=7．2(溶液A)，甲醇：乙腈=4：1(溶液B)，380mL A和620mL B混合作为流动相，流速2mL／min，进样量10μL，220nm下检测，以恒流洗脱方式在25min内分离了长春碱等4种成分。同时还研究了流动相组成、pH值等对分离效果的影响。对实际样品分析，取得了较好结果。     

阻抑动力学光度法测定环境水样中的痕量苯酚

基于在稀硫酸介质中，痕量苯酚能灵敏地阻抑高碘酸氧化苯胺蓝褪色，研究了该阻抑褪色反应的最佳条件及动力学参数，建立了测定痕量苯酚的新方法。该方法的线性范围为0-40.0μg/L，线性回归方程为1g(A1/A2)=0.638c 0.00117，相关系数r=0.9996，检出限为1.2μg/L。该方法简便，灵敏，选择性好，用于环境水样中痕量苯酚的测定，结果准确。     

Some possible surface processes involved in production of superacidity in sulfate promoted zirconium oxide

A series of samples has been prepared by impregnating zirconium oxide with ammonium sulfate and then calcining at different temperatures. The samples are characterized by XPS and IR spectroscopy. The results from the characterization reveal that the production of the surface superacidity of sulfate promoted zirconium oxide may involve some surface chemical processes: dispersion onto and interaction with, of ammonium sulfate, the surfaces of zirconium oxide; formation of the surface sulfato complex of zirconium and its gradual decomposition at even higher temperatures.The Project Supported by the National Natural Science Foundation of China.     

A New Sesquiterpene Lactone from Scorzonera austriaca

A new guaianolide was isolated from the roots of Scorzonera austriaca. The structurewas elucidated on the basis of spectral methods including 2D NMR.     

Synthesis and Potential Application of Novel C2-Symmetrical Bis（ferrocenyl） P2N Ligand

A novel chiral bis(ferrocenyl) P2N ligand 1 with C2-symmetry was synthesized through a four-step procedure from (R)-N,N-dimethyl-l-ferrocenylethylamine. In a model reaction of Pdcatalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate 6 with dimethyl malonate, good enantioselectivity (86% e.e.) was obtained.     

氨基酸和多肽在碱性硅胶载体上的固相衍生研究

为进行复杂体系中痕量生理活性物质 (如氨基酸和多肽等 )的高灵敏度分析 ,往往需要对其进行柱前或柱后的荧光衍生 -高效液相色谱或毛细管电泳分析 [1] .在一个存在着竞争反应的体系中 ,为保证样品有足够的反应产率 ,往往需使衍生试剂过量很多 ,这就使得衍生后的样品中必然含有高浓度的衍生试剂及其水解后形成的副产物 ,从而大大地干扰了分离与分析 .为解决这一问题 ,通常可采取溶剂萃取[2～ 5] 或加入 1 -金刚烷胺 [6 ,7] 或羟胺 [8,9] 等方法除去过量试剂 .但这些额外的处理使衍生方法更加烦琐 ,有时还导致收率的降低 .也有使用固相化的衍…     

Two New Polyoxygenated Cyclohexenes from Uvaria calamistrata

Inourearlierworkonthephytochemicalinvestigationoftheannonaceousplants,wehavereportedthepresenceofanarrayofpolyoxygenatedcyclohexenesinUvariagrandlpora,U.bonianaand,Annonamuricata,inwhichsomecyclohexenesandtheirderivatives,especiallysomea6-unsaturatedcyclohexenonesexistednaturallysuchasAM-landproducedbytheoxidationofallylichyhroxylg,,,p.incyclohexeneswithCrop/Py,havestrongactivityagainsthumancancercellh.es'-3.Inourcontinuousinvestigationofthemethanolextractoftherhizomeofanotherplant,Uvariacal…     

CH4/CO2 reforming over highly active catalysts that is Ce-promoted Ni supported on KIT-1 with wormlike pore structure

Russian Journal of Applied Chemistry - A new type of Ce-promoted Ni catalyst with KIT-1 as the support is prepared by using a sol-gel method. The catalyst exhibits excellent catalytic activity and...     

What Caused the Formation of the Absorption Maximum at 421 nm in vivo Spectra of Rhodopseudomonas palustris

A spectral peak at ~421 nm appeared in vivo spectrum of Rhodopseudomonas palustris CQV97 cultured in acetate–glutamate medium (M1) but not in acetate–ammonium sulfate medium (M2). However, the spectral origin of 421 nm peak was not clear and frequently attributed to carotenoid component(s). In this study, comparative analysis of the extracted components showed that magnesium protoporphyrin IX monomethylester (MPE) was accumulated as one of the predominate components in M1 culture. The amounts of bacteriochlorophyll a in M1 culture were higher than that in M2, whereas the amounts of carotenoids were nearly identical in both cultures. A simple, rapid and minimum interference with carotenoid and bacteriochlorophyll method to efficiently extract the compounds involving in the formation of 421 nm peak was developed in this study. Assembly of purified MPE with protein components from R. palustris in vitro demonstrated that MPE caused the formation of 421 nm peak. The localization analysis in vivo demonstrated it is MPE associating to protein components and accounting for the peak at ~421 nm. This work clarified the 421 nm peak in vivo mainly originated from MPE accumulation, and will be very helpful to further explore the physiological roles of MPE or its derivatives in photosynthesis.     

圆盘绕流近尾迹相干结构大涡模拟

对Re=22000圆盘近尾迹进行大涡模拟数值研究,通过对x/D=1,4处径向多点脉动速度进行快速傅里叶变换(FFT),发现三个特征频率,其对应的Strouhal数分别为0.035、0.123和1.3~1.7。分析表明,St_2=0.123为涡旋自然脱落频率,与文献结果相符;较小频率St_1=0.035,可能与回流区伸缩和剪切层附近涡旋脱落点周向旋转共同作用相关;而高频率St_3=1.3~1.7则与剪切层结构相关。最后对圆盘近尾迹流场作特征正交分解(POD),根据1~6模态的分布,分析大尺度结构的可能存在形式。