排序方式: 共有13条查询结果,搜索用时 62 毫秒
11.
利用茎环结构DNA的循环杂交放大作用和碱基C与Ag~+之间的稳定结构,设计了一种高灵敏性的表面增强拉曼生物传感器用于水样中Ag~+的检测。首先制备了携带有大量拉曼信号分子的纳米金生物条码作为拉曼信号探针。然后通过酰胺键将捕获DNA固载在磁珠表面上,利用C-Ag~+-C形成的稳定结构和链式循环杂交反应放大技术,将含有大量拉曼信号DNA分子的纳米金颗粒通过生物素和链霉亲和素的特异性结合到磁珠上,最后通过SERS技术实现了溶液中Ag~+的检测。最佳实验条件下,当固定磁珠捕获DNA浓度为1.0×10~(-7)M,Tris-HCl缓冲溶液为pH7.4,37℃下杂交反应2.5 h后,Ag~+的浓度与拉曼信号强度呈良好的线性关系,测定线性范围为1.0×10~(-7)~1.0×10~(-12)M,检测限1.0×10~(-12)M(S/N=3)。该传感器用于海产品中Ag~+的测定,测定值与ICP-AES的测定值基本一致。 相似文献
12.
13.
Asymmetric reduction of acetophenone O-methyloxime with reagents in situ prepared from L-pronne and borane has been investigated. A series of conditions opfimiTation were made, including an examination of the effect of the temperature of ratalyst pretreatment, the temperature of reduction, the amount of borane, the additive, the solvent, the reducing agent and various chiral anxiHaries on the enanfioselecfivlty. Under the opti-mal condition, (S)-a-phenylethylamlne was obtained in 53% yield with 83.1% ee in the presence of 25 mol% L-proline. 相似文献