The thermodynamic partitioning behavior of solutes into immobilized artificial membrane(IAM) and n-octanol/water systems was investigated, including acidic,basic,and amphoteric substances.In an n-octanol/buffer system...The thermodynamic partitioning behavior of solutes into immobilized artificial membrane(IAM) and n-octanol/water systems was investigated, including acidic,basic,and amphoteric substances.In an n-octanol/buffer system,partitioning process was entropy-dominated for the most studied drugs,while partitioning of oxolinic and nalidixic acids into n-octanol phase was enthalpy-driven.In IAM chromatography,partitioning into membrane for the studied solutes was enthalpy-driven and an exothermal process.In conclusion,there is a significant difference of solutes′ partitioning mechanism into either IAM or an n-octanol phase,therefore,presenting the theoretical basis for differing lipophilicity measuring scale.展开更多
文摘The thermodynamic partitioning behavior of solutes into immobilized artificial membrane(IAM) and n-octanol/water systems was investigated, including acidic,basic,and amphoteric substances.In an n-octanol/buffer system,partitioning process was entropy-dominated for the most studied drugs,while partitioning of oxolinic and nalidixic acids into n-octanol phase was enthalpy-driven.In IAM chromatography,partitioning into membrane for the studied solutes was enthalpy-driven and an exothermal process.In conclusion,there is a significant difference of solutes′ partitioning mechanism into either IAM or an n-octanol phase,therefore,presenting the theoretical basis for differing lipophilicity measuring scale.
文摘讨论了蒸汽顶空富集时,水中目标有机物的回收率与正辛醇/水分配系数和蒸气压之间的联系,结果表明氯苯类挥发性有机污染物在水中的回收率与正辛醇/水分配系数(lg Kow)间存在一定的规律:当lg Kow值<5.5时,回收率随lg Kow值的增大而增大;当lg Kow值>5.5时,回收率随lg Kow值的增大而降低。回收率与1.0 k Pa蒸气压温度的关系分析可以得出相似的规律,回收率值有一个拐点,当1.0 k Pa蒸气压温度<120℃时,回收率随着有机物蒸气压增大而增大,1.0 k Pa蒸气压温度>120℃时,回收率反而随着有机物蒸气压增大而降低。氯苯类有机物的回收率既与有机物的lg Kow值、蒸气压正相关,又受到lg Kow值、蒸气压的制约。
