The retention mechanism of four major carotenoids, two xanthophylls (i.e., lutein and zeaxanthin) and two carotenes (i.e., lycopene and β-carotene), was investigated in reversed-phase liquid chromatography with the aim of thermodynamic analysis. The experimental variables considered in this study were the composition of mobile phase (MP) and the temperature. Chromatographic elutions were undertaken under linear, isocratic conditions by using a C18 stationary phase, four different MP compositions (by varying the ratio methanol/acetonitrile from 66.5/28.5 to 47.5/47.5 v/v), and column temperatures in the range 283–313 K. Traditional Van't Hoff analysis has been used to estimate changes of standard enthalpy (ΔH°) and Gibbs free energy (ΔG°) associated with the solute transfer from the mobile to the stationary phase at each mobile phase composition. The thermodynamic quantities have been correlated to the structure of investigated carotenoids and their interaction with the octadecyl silica stationary phase.
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机译：为了进行热力学分析，在反相液相色谱中研究了四种主要类胡萝卜素（两种叶黄素（即叶黄素和玉米黄质）和两种胡萝卜素（即番茄红素和β-胡萝卜素）的保留机理。本研究中考虑的实验变量是流动相（MP）的组成和温度。色谱洗脱是在线性，等度条件下进行的，使用C18固定相，四种不同的MP组成（通过将甲醇/乙腈的比率从66.5 / 28.5更改为47.5 / 47.5 v / v），柱温在283-313范围内K.传统的Van't Hoff分析已用于估算与在每种流动相组成下从溶质向固定相转移的溶质相关的标准焓（ΔH°）和吉布斯自由能（ΔG°）的变化。热力学量已经与所研究的类胡萝卜素的结构及其与十八烷基二氧化硅固定相的相互作用相关。
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