对二甲苯正辛醇-水分配系数的测定

Determination of n-Octanol-Water Partition Coefficient of p-Xylene

采用摇瓶法对对二甲苯正辛醇-水分配系数进行测定,首先进行波长扫描,确定对二甲苯的测定波长为227nm。在此波长条件下,对5种不同浓度的对二甲苯标样进行测定,得到对二甲苯的校准曲线:y=0.0065x-0.0178,可决系数R2=0.9925。振荡2.5h后,对二甲苯在两相中达到一个平衡状态,此时lgKow为3.09。该方法所需仪器简单,精密度较高,可用于高脂溶性有机化合物的正辛醇-水分配系数的测定。

Shake flask method was used to determinate （Kow） of the n-octanol-water partition coefficient of p-xylene. Firstly, the detection wavelength of p-xylene was 227nm by ultraviolet scanning. Standard curve was drew by analysis of different concentration five standards under the same conditions,and regression equation was y=0. 0065x-0. 0178 with determination coefficients of 0. 9925. The biphase distributions of p-xylene reached equilibrium after shaking 2.5h,and lgKow was 3. 09. The method is accurate, simple with easy operation and high precision, which is applied to determination of the n-octanol/water partition coefficient of organic compound with high fat-soluble.