排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
高效液相色谱切换波长法测定油菜内源激素 总被引:1,自引:0,他引:1
采用反相高效液相色谱法(HPLC)切换波长法同时测定油菜中的内源激素赤霉素(GA3)、3-吲哚乙酸(IAA)和脱落酸(ABA),以甲醇:水:乙腈(20:60:20)为流动相,结果显示其检出限分别为GA3:0.08mg/L;IAA:0.015mg/L;ABA:0.025mg/L,比单波长检测的检出限提高了4-10倍;相对标准偏差(RSD)分别为GA3:6.3%,IAA:4.34%,ABA:7.95%.本实验采用切换波长法,显著减低了各组分的检出限,建立了一种以高灵敏度对多组分体系同时进行检测的方法.同时为快速、准确测定油菜内源激素提供了可靠方法. 相似文献
2.
3.
4.
采用饱和水溶液法制备了大豆苷元分别与两种氨基修饰β-环糊精(ACD) 即单-6-氨基-β-环糊精(NCD) 和单-6-乙二胺基-β-环糊精(ENCD) 的固体包合物,并获得最佳包合条件:大豆苷元与环糊精投料比为3∶1(n/n) ,搅拌时间为72 h,分别获得83%和67%的产率.利用X-射线粉末衍射和热重分析对其进行了表征,证实了两种包合物的形成.利用Job′s曲线法确定了主客体的包合比为1∶1,并利用荧光光谱滴定分析测得其包合稳定常数KS分别为899.2和203.8 L/mol.水溶性实验表明,通过与NCD和ENCD形成包合物,25℃下大豆苷元在水中的溶解度由原来的8.31 μg/mL增至15.2和13.2 mg/mL,分别提高了约1800和1500倍. 相似文献
5.
Wei Zhang Meng-Yun Rao Zhong-Jun Cheng Xiao-Yan Zhu Kai Gao Jian Yang Bo Yang Xia-Li Liao 《Chemical Papers》2015,69(5):716-721
The practical synthetic preparation of glutaric acid has remained a major challenge to date. In the present study, glutaric acid was synthesised by way of one-pot diazoniation/hydrogenation of the readily available l-glutamic acid under aqueous conditions on a gram-scale with good yields. This is the first example of the deamination of the aliphatic primary amine via diazoniation and could afford a practical approach to the production of glutaric acid. 相似文献
6.
7.
8.
Xia-Li Liao Xiao-Ying Xu Chun Wang Zhi-Jun Wu Dong-Mei Fang Guo-Lin Zhang Shi-Wei Luo 《Monatshefte für Chemie / Chemical Monthly》2011,2(4):1105-1109
Abstract
The MS n spectra of three bimetallic oxovanadium complexes were obtained using an ion trap. The fragmentation pathways were elucidated. Common features and major differences between ESI–QTOF–MS/MS and ESI–IT–MS n spectra were compared. Electron affinities of several radical molecular anions were calculated by DFT and these could be used as an indicator of the ions’ stability. 相似文献9.
Xia-Li Ding Yuan-Qi Zhai Dr. Tian Han Dr. Wei-Peng Chen Dr. You-Song Ding Prof. Dr. Yan-Zhen Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(8):2623-2627
Three six-coordinate DyIII single-molecule magnets (SMMs) [Dy(OtBu)2(L)4]+ with local D4h symmetry are obtained by optimizing the equatorial ligands. One of the compounds with L=4-phenylpyridine shows an energy barrier (Ueff) of 2075(11) K, which is the third largest Ueff, and the first Ueff>2000 K for SMMs with axial-type symmetry so far. Ab initio analysis indicates that the exceptional uniaxial magnetic anisotropy is deeply related to the axially compressed octahedral geometry. This work provides a new insight into the local D4h symmetry for high-performance SMMs. 相似文献
10.
Dan Xiao Bo Yang Yu-Lin Zhao Xia-Li Liao Xue-Min Yang Fen Wang Yun-Jian Chen Rong-Guang Zhou 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(3-4):349-356
The characterization, inclusion complexation behavior and binding ability of the inclusion complexes of dihydroartemisinin with β-cyclodextrin and its derivatives, sulfobutyl ether β-cyclodextrin (SBE-β-CD), mono[6-(2-aminoethylamino)-6-deoxy]-β-cyclodextrin (en-β-CD) and mono{6-[2-(2-aminoethylamino)ethylamino]-6-deoxy}-β-cyclodextrin (dien-β-CD), were studied using phenolphthalein as a spectral probe. Spectral titration was performed in aqueous buffer solution (pH ca. 10.5) at 25 °C to determine the binding constants. The inclusion complexation behaviors were investigated in both solution and solid state by means of NMR, TG, XRD. The results showed that the water solubility and thermal stability of dihydroartemisinin were significantly increased in the inclusion complex with cyclodextrins (CDs). According to 1H NMR and 2D NMR spectroscopy (ROESY), the A, B rings of dihydroartemisinin can be included into the cavity of CDs. The enhanced binding ability of CDs towards dihydroartemisinin was discussed from the viewpoint of the size/shape-fit concept and multiple recognition mechanism between host and guest. 相似文献