基于分子参数的药物小肠吸收预测模型

选择100个化合物作为数据集,随机选取其中80个为训练集,其他分子为验证集,并为每个化合物分子计算了30个参数.通过采用五种不同多元线性回归分析方法对其训练模拟,建立了数学模型,并用验证集检验了所建模型的预测能力.结果发现向后筛选法为最优小肠吸收建模方法.由该法所建模型的统计结果良好(R2>0.80),应用于验证集时也表现出较强预测能力.该模型确定了对小肠吸收影响较大的分子参数,有助于指导进一步的新药筛选和开发.     

高效液相色谱法同时测定化工废水中乙醇酸、乙醛酸和草酸的含量

水样经0.22μm亲水针筒式过滤器过滤,根据需要进行稀释后,在Acclaim MixedMode WAX-1色谱柱(4.6mm×150mm,5μm)上进行分离,以90mmol·L~(-1)磷酸盐缓冲溶液[pH 6.0,溶剂为10%(体积分数)乙腈溶液]为流动相进行等度洗脱,在波长210nm处进行紫外检测。结果表明:乙醇酸、乙醛酸和草酸的质量浓度分别在3.51～2 500,4.20～8 000,18.0～800mg·L~(-1)内与对应的峰面积呈现线性关系,检出限(3S/N)分别为1.00,1.24,4.82mg·L~(-1),测定下限(10S/N)分别为3.32,4.15,16.1mg·L~(-1)。对实际样品进行加标回收试验,乙醇酸、乙醛酸和草酸的回收率分别在98.2%～101%,99.6%～103%,99.2%～101%之间,测定值的相对标准偏差(n=6)分别为0.77%,0.65%,1.1%。     

柱前衍生高效液相色谱法测定化工废水中乙二胺

建立了化工废水中乙二胺含量的柱前衍生高效液相色谱分析方法。利用N-(苄氧羰基氧基)琥珀酰亚胺(CBZ-OSu)与乙二胺在80℃下反应5 min后,由高效液相色谱-二极管阵列检测器进行分离检测,色谱分析时间为5 min。色谱柱为Waters Xbridge C18(150×4.6 mm,5μm);流动相为60%乙腈水溶液;1.0 m L/min流速下,等度洗脱;210 nm波长处检测。结果表明,乙二胺质量浓度在0.60~100 mg/L范围内,与对应的峰面积呈现良好的线性关系,相关系数为0.9989;方法的检测限为0.17 mg/L(S/N=3),定量限为0.58 mg/L(S/N=10);实际样品的加标回收率为95.5%~102.1%,相对标准偏差为0.14%;已用于测定化工废水中乙二胺。     

Structure and dynamics of ordered water in a thick nanofilm on ionic surfaces

The structure and dynamics of water in a thick film on an ionic surface are studied by molecular dynamic simulations. We find that there is a dense monolayer of water molecules in the vicinity of the surface. Water molecules within this layer not only show an upright hydrogen-down orientation, but also an upright hydrogen-up orientation. Thus, water molecules in this layer can form hydrogen bonds with water molecules in the next layer. Therefore, the two-dimensional hydrogen bond network of the first layer is disrupted, mainly due to the O atoms in this layer, which are affected by the next layer and are unstable. Moreover, these water molecules exhibit delayed dynamic behavior with relatively long residence time compared with those bulk-like molecules in the other layers. Our study should be helpful to further understand the influence of water film thickness on the interfacial water at the solid-liquid interface.