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多色蓝在核酸分子上的Langmuir聚集吸附 总被引:4,自引:0,他引:4
用微相吸附-光谱修正(MPASC)新技术研究核酸与多色蓝(PCB)探针分子间的相互作用,分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究,测定了结合产物的物理化学参数:结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104, KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103(mo1-1•L )•cm-1, ε(RNA-PCB, 625 nm)=3.85×103 (mol-1•L)•cm-1.结果表明, RNA分子仅形成约60%双螺旋结构链,核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定,结果良好. 相似文献
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956.
Jin‐Tang Cheng Juan He Xing‐Yao Li Xing‐De Wu Li‐Dong Shao Liao‐Bin Dong Xu Deng Xiu Gao Li‐Yan Peng Xiao Cheng Yan Li Qin‐Shi Zhao 《Helvetica chimica acta》2012,95(7):1158-1163
Three new monosubstituted sucrose fatty acid esters, 1 – 3 , were isolated from Equisetum hiemale L., together with nine known compounds, 4 – 12 . Their structures were elucidated by spectroscopic analyses. Compounds 5, 6 , and 10 – 12 were isolated from the title plant for the first time. All these compounds were evaluated for their cytotoxic activity. However, none of them was cytotoxic. 相似文献
957.
Two new 4‐hydroxyisoflavanes, cordifoliflavanes A and B (1 and 2), were isolated from the roots of Codonopsis cordifolioidea. Their structures were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR techniques. Compounds 1 and 2 were tested for their anti‐HIV‐1 activities and anti‐tobacco mosaic virus activities. The results showed that compounds 1 and 2 have modest anti‐HIV‐1 activities and anti‐tobacco mosaic virus activities, respectively. 相似文献
958.
A new method using a column packed with graphene as adsorbent was developed for the preconcentration of trace amounts of cobalt (Co) and nickel (Ni) prior to their determinations by flame atomic absorption spectrometry. Several factors influencing the extraction efficiency of Co and Ni and their subsequent determinations, such as pH, amounts of the chelating agent, flow rates of sample and eluent solution, eluent type and its volume, breakthrough volume, and adsorption capacity were established. Under the optimum conditions, the calibration graphs were linear in the range of 4.0‐200.0 μg L?1 and 5.0‐200.0 μg L?1 with detection limits of 0.36 μg L?1 and 0.51 μg L?1 for Co and Ni, respectively. Good relative standard deviations for ten determinations of 100.0 μg L?1 of Co and Ni were 3.2 and 3.6%, respectively. The results for determination of Co and Ni in tap water, river water, sea water, vegetable and spiked samples have demonstrated the accuracy and applicability of the proposed method. To validate the proposed method, three certified reference materials of environment water (GSBZ 50030‐94 and GSB 07‐1186‐2000) and tomato leaf (GSBZ 51001‐94) were analyzed, and the determined values were in good agreement with the certified values. 相似文献
959.
E‐Hu Liu Ting Zhou Guo‐Bin Li Jing Li Xiu‐Ning Huang Feng Pan Ning Gao 《Journal of separation science》2012,35(2):263-272
The multiple bioactive constituents in Hedyotis diffusa Willd. (H. diffusa) were extracted and characterized by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC‐ESI‐MSn). The optimized separation condition was obtained using an Agilent ZorBax SB‐C18 column (4.6×150 mm, 5 μm) and gradient elution with water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid), under which baseline separation for the majority of compounds was achieved. Among the compounds detected, 14 iridoid glucosides, 10 flavonoids, 7 anthraquinones, 1 coumarin and 1 triterpene were unambiguously identified or tentatively characterized based on their retention times and mass spectra in comparison with the data from standards or references. The fragmentation behavior for different types of constituents was also investigated, which could contribute to the elucidation of these constituents in H. diffusa. The present study reveals that even more iridoid glycosides were found in H. diffusa than hitherto assumed. The occurrence of two iridoid glucosides and five flavonoids in particular has not yet been described. This paper marks the first report on the structural characterization of chemical compounds in H. diffusa by a developed HPLC‐ESI‐MSn method. 相似文献
960.
Yi‐Wen Chen Hai‐Xia Wei Xiu‐Guang Wang Prof. Dr. Dong‐Zhao Gao Ya‐Qiu Sun Guo‐Ying Zhang Yan‐Yan Xu 《无机化学与普通化学杂志》2012,638(9):1328-1334
Three new one‐dimensional (1D) chain metal–nitroxide complexes {[Cu(NIT4Py)2(suc)(H2O)] · 3H2O}n ( 1 ), {[Cd(NIT4Py)2(suc)(H2O)] · [Cd(NIT4Py)2(suc)(H2O)2] · 3H2O}n ( 2 ), and {[Zn(NIT4Py)(glu)(H2O)] · H2O}n ( 3 ) [NIT4Py = 2‐(4′‐pyridyl)‐4, 4, 5, 5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, suc = succinate anion and glu = glutarate anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that the three complexes crystallize in neutral 1D chains in which the metal‐nitroxide units are linked by flexible dicarboxylate anions. The succinate anions only adopt trans configuration in complexes 1 and 2 , whereas the glutarate anion has gauche/anti conformation in complex 3 . Magnetic measurements show that complex 1 exhibits weak antiferromagnetic interactions between the copper ions and the nitroxides. 相似文献