Institute of Chemical Methodologies, Italian National Council of Research, Area della Ricerca di Roma, Via Salaria Km 29, 300-00015 Monterotondo Scalo, Rome, Italy.
J Chromatogr A. 2010 Feb 12;1217(7):1175-82. doi: 10.1016/j.chroma.2009.07.053. Epub 2009 Aug 3.
In this paper a phenyl-carbamate-propyl-beta-cyclodextrin stationary phase was employed for the enantioseparation of several flavonoids, including flavanones and methoxyflavanones by using nano-liquid chromatography (nano-LC). The same stationary phase was also used for the diastereoisomeric separation of two flavanone glycosides. The compounds: flavanone, 2'-hydroxyflavanone, 4'-hydroxyflavanone, 6-hydroxyflavanone, 7-hydroxyflavanone, 4'-methoxyflavanone, 6-methoxyflavanone, 7-methoxyflavanone, hesperetin, hesperidin, naringenin and naringin were studied using reversed, polar organic and normal elution modes. The effect of the nature and composition of the mobile phase (organic modifier type, buffer and water content in the reversed phase mode) on the enantioresolution (R(s)), retention factor (k) and enantioselectivity (alpha) were investigated. Baseline resolution of all studied flavonoids, with the exception of 2'-hydroxyflavanone and naringin, was achieved in reversed phase mode using a mixture of MeOH/H(2)O at different ratios as mobile phase. Good results, in terms of peak efficiency and short analysis time, were obtained adding 1% triethylammonium acetate pH 4.5 buffer to MeOH/H(2)O mixture. The separation of the studied compounds was also performed in polar organic mode. By using 100% of MeOH as mobile phase, the resolution was achieved for the studied analytes, except for 7-hydroxyflavanone, 2'-hydroxyflavanone, naringenin, hesperidin and naringin. Normal mode was tested employing a mixture of EtOH/hexane/TFA as mobile phase achieving the enantiomeric and diastereomeric separation of only hesperetin and hesperidin, respectively. The use of nano-LC technique for the resolution of flavanones optical isomers allowed to achieve good resolutions in shorter analysis time compared to the results reported in literature with conventional HPLC.
本文采用苯甲酰基-β-环糊精手性固定相，通过纳流液相色谱（nano-LC）对手性分离几种黄酮类化合物，包括黄酮和甲氧基黄酮。同一固定相也用于两种黄酮糖苷的非对映异构体分离。所研究的化合物有：黄酮、2'-羟基黄酮、4'-羟基黄酮、6-羟基黄酮、7-羟基黄酮、4'-甲氧基黄酮、6-甲氧基黄酮、7-甲氧基黄酮、橙皮素、橙皮苷、柚皮苷和柚皮苷。采用反相、极性有机和正相洗脱模式研究了这些化合物。考察了流动相的性质和组成（反相模式中的有机改性剂类型、缓冲液和水含量）对映体拆分（R(s)）、保留因子（k）和对映选择性（α）的影响。除 2'-羟基黄酮和柚皮苷外，所有研究的黄酮类化合物在反相模式下均采用不同比例的甲醇/水作为流动相混合物实现了基线分离。在甲醇/水混合物中加入 1%三乙胺乙酸盐 pH4.5 缓冲液，可获得良好的峰效率和短分析时间的结果。在极性有机模式下也进行了研究化合物的分离。采用 100%甲醇作为流动相，除 7-羟基黄酮、2'-羟基黄酮、柚皮苷、橙皮苷和柚皮苷外，研究的分析物也实现了分离。采用乙醇/己烷/TFA 作为流动相的正相模式仅实现了橙皮素和橙皮苷的对映体和非对映体分离。与传统 HPLC 相比，纳流液相色谱技术用于分离黄酮类光学异构体可以在更短的分析时间内实现良好的分辨率。
