气相色谱中保留值与进样量的关系

Relationship between Retention and Sample Size in Gas Chromatography

提出了测量气相色谱中吸附等温线的新方法 ,用不同进样量下测定的容量因子计算平衡时气 固两相组分浓度。利用建立的方法分别测量了正 己烷、正 壬烷和正 十一烷在邻苯二甲酸二辛酯 (DOP)、阿皮松 L(Apiezon)和 β ,β′ 氧二丙腈 (ODPN)柱上的吸附等温线 ,讨论了色谱峰形状与吸附等温线的对应关系。研究了气相色谱中进样量对保留值的影响 ,利用佛伦德利希 (Freundlich)吸附等温式导出了描述保留值与进样量关系的数学表达式。理论和实验证明 ,保留值与进样量具有良好的对数线性关系。

A new method used to measure the adsorption isotherm has been proposed in gas chromatography. It is based on the constituent concentration of gas phase and stationary phase at the equilibrium can be calculated by using capacity factor determined under injecting different sample size. The adsorption isotherms of n-bexane, n-nonane and n-undecane on dioctyl phthalate(DOP), Apiezon-L and beta,beta'-oxydipropionitrile (ODPN) column were determined using the established method, respectively. The corresponding relation between the chromatographic peak shape and adsorption isotherm type was also discussed. The influence of sample size on the retention was investigated in gas chromatography. A mathematical expression describing the relationship of the retention and sample size was derived from Freundlich adsorption isotherm equation. The theory and experiment show that the logarithm of the capacity factor and sample size has good linear relation.