Department of Chemistry and Center of Excellence for Innovation in Chemistry and Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand.
Analytical Sciences and National Doping Test Institute, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand.
J Chromatogr A. 2020 Dec 20;1634:461668. doi: 10.1016/j.chroma.2020.461668. Epub 2020 Nov 2.
This work proposes an experimental method for the estimation of the phase ratio of reversed-phase C8 columns by employing the equation log(k)=alog(K)+log(Φ), where k is the retention factor, Kis the octane-mobile phase partition coefficient, a is a proportionality constant and Φ is the phase ratio (defined as volume ratio of the stationary phase to the mobile phase). The immiscible liquid octane and mobile phase are chosen as the surrogate model for the C8 stationary phase and mobile phase of the chromatographic system. The octane-mobile phase is used for measuring the partition coefficient K of six compounds of the homologous series of linear alkylbenzenes, viz. benzene, toluene, ethylbenzene, propylbenzene, butylbenzene and pentylbenzene. The distribution of a compound between the octane and mobile phase is proposed to simulate the partitioning process in the chromatography. The retention factor k of each compound is measured using the same mobile phase for two C8 columns (Zorbax Eclipse XDB-C8 and Symmetry C8). The set of data of k and K is fitted to the above linear equation to give the best-fit values of a and log(Φ) for each column and various mobile phase compositions (methanol-water or acetonitrile-water). The regression analyses have coefficients of determination r > 0.992. This observed linear relationship can therefore be expressed as k=KΦ. The experimental values of Φ for the C8 columns are in the range of 0.206 to 0.842, with a from 0.544 to 0.811, respectively.
本工作提出了一种通过方程 log(k)=alog(K)+log(Φ) 来估计反相 C8 柱的相比的实验方法，其中 k 是保留因子，K 是辛烷-流动相分配系数，a 是比例常数，Φ 是相比（定义为固定相和流动相的体积比）。不混溶的辛烷和流动相被选为 C8 固定相和色谱系统的流动相的替代模型。辛烷-流动相用于测量六个直链烷基苯同系物的化合物的分配系数 K，即苯、甲苯、乙苯、丙苯、丁苯和戊苯。建议将化合物在辛烷和流动相之间的分布模拟色谱中的分配过程。使用相同的流动相测量每种化合物的保留因子 k 对于两个 C8 柱（Zorbax Eclipse XDB-C8 和 Symmetry C8）。将 k 和 K 的数据集拟合到上述线性方程中，以获得每个柱和各种流动相组成（甲醇-水或乙腈-水）的最佳拟合值 a 和 log(Φ)。回归分析的确定系数 r > 0.992。因此，可以将观察到的线性关系表示为 k=KΦ。C8 柱的实验值 Φ 范围为 0.206 至 0.842，a 值范围为 0.544 至 0.811。
