de Groot G, Koops R, Hogendoorn E A, Goewie C E, Savelkoul T J, van Vloten P
Laboratory for Residue Analysis, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
J Chromatogr. 1988 Dec 2;456(1):71-81. doi: 10.1016/0021-9673(86)80007-3.
A sensitive method is described for the simultaneous determination of glycyrrhizin and glycyrrhetic acid in human plasma. Quantitation is by high-performance liquid chromatography using ion-pair chromatography on a reversed-phase column. Variable-wavelength ultraviolet detection is employed. For the extraction of both compounds from plasma, a new solid-phase ion-pair extraction procedure using octadecylsilane columns was developed. Because of the strong forces involved in the protein binding of glycyrrhizin, quantitative extraction of this compound from plasma was possible only after an alkaline pH shift. A considerable improvement in selectivity and sensitivity was obtained by automated column switching involving on-line preseparation of the solid-phase extract on a short precolumn and chromatographic analysis of a heart-cut from the precolumn eluate. The limit of detection of both glycyrrhizin and glycyrrhetic acid was 0.1 mg/l in 0.5 ml of plasma. From a preliminary study in human volunteers, it was concluded that glycyrrhetic acid rather than glycyrrhizin is preferred in a study in human volunteers to assess the zero effect level of glycyrrhizin.
本文描述了一种同时测定人血浆中甘草酸和甘草次酸的灵敏方法。采用反相柱上的离子对色谱法通过高效液相色谱法定量。使用可变波长紫外检测。为了从血浆中提取这两种化合物，开发了一种使用十八烷基硅烷柱的新型固相离子对萃取方法。由于甘草酸与蛋白质结合力很强，只有在碱性pH值改变后才可能从血浆中定量提取该化合物。通过自动柱切换实现了选择性和灵敏度的显著提高，包括在短预柱上对固相提取物进行在线预分离以及对预柱洗脱液的中心切割部分进行色谱分析。在0.5 ml血浆中，甘草酸和甘草次酸的检测限均为0.1 mg/l。通过对人类志愿者的初步研究得出结论，在评估甘草酸的零效应水平的人类志愿者研究中，优选甘草次酸而非甘草酸。
