Abstract The elution behavior of four sesquiterpenoids in volatile oil of Curcumae Rhizoma on reverse-phase high-performance liquid chromatography with methyl-β-cyclodextrin as mobile phase additive was studied, including germacrone, curzerene, furanodiene, and β-elemene. Stoichiometric ratio and apparent formation constants of inclusion complex formed by methyl-β-cyclodextrin and each analyte were calculated by varying the concentration of the additive in the mobile phase composed of methanol and water (90:10, v/v), in which the association constant for inclusion complex formed by the organic modifier methanol and methyl-β-cyclodextrin was also determined. Results showed that the stoichiometric ratio of all the inclusion complex was 1:1 when 0–9 mmol L−1 of methyl-β-cyclodextrin was added in the mobile phase. Unusual retention behavior of the analyte germacrone was found, which was further investigated by the calculation of thermodynamic parameters. Meanwhile, enthalpy and entropy of the inclusion complexes and solute-stationary phase interactions were determined by linear van’t Hoff plots. Graphical Abstract

中文翻译：

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以甲基-β-环糊精为流动添加剂的反相固定相上莪术挥发油中四种倍半萜类化合物的色谱研究

摘要 以甲基-β-环糊精为流动相添加剂，研究了姜黄酮、莪术烯、呋喃二烯和β-榄香烯四种倍半萜类化合物在莪术挥发油中的洗脱行为。通过改变由甲醇和水 (90:10, v/v) 组成的流动相中添加剂的浓度，计算了由甲基-β-环糊精与每种分析物形成的包合物的化学计量比和表观形成常数，其中还测定了由有机改性剂甲醇和甲基-β-环糊精形成的包合物的缔合常数。结果表明，当流动相中加入 0-9 mmol L-1 甲基-β-环糊精时，所有包合物的化学计量比为 1:1。发现分析物germacrone 的异常保留行为，通过热力学参数的计算进一步研究。同时，包合物的焓和熵以及溶质-固定相相互作用由线性范特霍夫图确定。图形概要