The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly tim...The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly times and concentration were also investigated.A two-step adsorption kinetics has been confirmed:the fast adsorption process and the following long-term reorganization.The equilibrium constant(K)for the adsorptioon and the interaction factor between adsorbate-adsorbate molecules () were evaluated based on the Frumkin isotherm and determined to be (3. 17±0. 13)× 106 mol.L(-1) and -0.34±0.04, respectively The Gibbs free energy (G)of SAM was determined to be -(37. 07±0. 13)kJ.mol(-1)展开更多
采用紫外光谱定性定量分析野生植物茅莓主要有效成分黄酮化合物,并对其进行液相色谱-电喷雾质谱联用、薄层色谱原位表面增强拉曼散射研究。液相色谱流动相A:CH3OH,B:H2O+1%乙酸,液相色谱流出时间16.21 m in的化合物为六羟基双氢黄酮醇...采用紫外光谱定性定量分析野生植物茅莓主要有效成分黄酮化合物,并对其进行液相色谱-电喷雾质谱联用、薄层色谱原位表面增强拉曼散射研究。液相色谱流动相A:CH3OH,B:H2O+1%乙酸,液相色谱流出时间16.21 m in的化合物为六羟基双氢黄酮醇二聚体形式,分子量640,占总黄酮的91.71%;流出时间19.61 m in的化合物分子量448,为槲皮甙,占总黄酮的8.29%。茅莓总黄酮经聚酰胺薄层色谱板分离,获得两个斑点:R f1=0.14,R f2=0.47;分别制备灰银胶和溴化银光致还原银溶胶表面增强基底,在样品薄层色谱两个斑点原位分别获得2种黄酮化合物的表面增强拉曼光谱,在2种表面增强基底作用下,都能观察到μg量黄酮化合物特征拉曼光谱,并比较了2种色谱分离与指纹检测联用技术。展开更多
文摘The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly times and concentration were also investigated.A two-step adsorption kinetics has been confirmed:the fast adsorption process and the following long-term reorganization.The equilibrium constant(K)for the adsorptioon and the interaction factor between adsorbate-adsorbate molecules () were evaluated based on the Frumkin isotherm and determined to be (3. 17±0. 13)× 106 mol.L(-1) and -0.34±0.04, respectively The Gibbs free energy (G)of SAM was determined to be -(37. 07±0. 13)kJ.mol(-1)
文摘采用紫外光谱定性定量分析野生植物茅莓主要有效成分黄酮化合物,并对其进行液相色谱-电喷雾质谱联用、薄层色谱原位表面增强拉曼散射研究。液相色谱流动相A:CH3OH,B:H2O+1%乙酸,液相色谱流出时间16.21 m in的化合物为六羟基双氢黄酮醇二聚体形式,分子量640,占总黄酮的91.71%;流出时间19.61 m in的化合物分子量448,为槲皮甙,占总黄酮的8.29%。茅莓总黄酮经聚酰胺薄层色谱板分离,获得两个斑点:R f1=0.14,R f2=0.47;分别制备灰银胶和溴化银光致还原银溶胶表面增强基底,在样品薄层色谱两个斑点原位分别获得2种黄酮化合物的表面增强拉曼光谱,在2种表面增强基底作用下,都能观察到μg量黄酮化合物特征拉曼光谱,并比较了2种色谱分离与指纹检测联用技术。
