改变相比/顶空气相色谱法测定水中苯的分配常数及其含量

Determination of Partition Coefficient of Benzene in Water and Its Content Using Phase Ratio Variation Method with Static Headspace Gas Chromatography

推导了改变气液相比/顶空气相色谱法测定水中苯的分配常数及其含量的基本关系式。采用全挥发技术制备气体标样测定校正因子。通过测定3个不同相比的顶空浓度,计算顶空浓度倒数与相比之间的线性回归方程,测定了23℃时苯在纯水中的分配常数为5 878(亨利常数为0 170),与文献值的误差为5 22%。实际测定水样中苯的质量浓度为0 348mg/L,与配制值0 357mg/L的相对误差为2 52%。方法检出限可达3 5×10-3mg/L。

A novel accurate and experimentally simple method has been developed to determine dimensionless partition coefficient and concentration of benzene in water using various phase ratios with the static headspace gas chromatographic method. The method used three different gasliquid volume ratios in the headspace vials to achieve different equilibrium concentrations in the gas phase. The partition coefficient and concentration of benzene in water were determined by using regression analysis of a headspace system based on mass balance principle. Linear equation between reciprocal of headspace peak area and phase ratio was 1/A=1931×10-6R+1135×10-5 with correlation coefficient of 0999?6. The partition coefficient for benzene in water was 5878 (Henry Law Constant was 0170) at 23 ℃ with a relative error of 522% compared with literature data. Limit of detection for the method was 35×10-3 mg/L. Standard vapor sample of benzene was prepared by full volatile technique. 