Three polysaccharide-based chiral stationary phases, Sepapak®1, Sepapak®2 and Sepapak®3 have been evaluated in the present work for the stereoisomer separation of a group of 12 flavonoids including flavanones (flavanone, 4-methoxyflavanone, 6-methoxyflavanone, 7-methoxyflavanone, 2-hydroxyflavanone, 4-hydroxyflavanone, 6-hydroxyflavanone, 7-hydroxyflavanone, hesperetin, narin-genin) and flavanone glycosides (hesperidin, naringin) by nano-liquid chromatography (nano-LC). The behaviour of these chiral stationary phases (CSPs) towards the selected compounds was studied in capil-lary columns (100 m internal diameter (i.d.)) packed with the above mentioned CSPs using polar organic, reversed and normal elution modes. The influence of nature and composition of the mobile phase in terms of concentration and type of organic modifier, buffer type and water content (reversed phase elu-tion mode) on the enantioresolution (Rs), retention factor (k) and enantioselectivity (?) was evaluated. Sepapak®3 showed the best chromatographic results in terms of enantioresolution, enantioselectiv-ity and short analysis time, employing a polar organic phase mode. A mixture of methanol/isopropanol (20/80, v/v) as mobile phase enabled the chiral separation of eight flavanones with enantioresolution factor (Rs) in the range 1.15-4.18. The same analytes were also resolved employing reversed and nor-mal phase modes with mixtures of methanol/water and hexane/ethanol at different ratios as mobile phases, respectively. Loss in resolution for some compounds, broaden peaks and longer analysis times were observed with these last two chromatographic elution modes. Afterwards, a comparison with the other two CSPs was performed. A lower discrimination ability of Sepapak®1 and Sepapak®2 towards all the studied flavanoids was observed. However, Sepapak®1 allowed the separation of naringenin enantiomers and naringin stereoisomers in polar organic phase which were not resolved with the other two CSPs.
Evaluation of novel amylose and cellulose-based chiral stationary phases for the stereoisomer separation of flavanones by means of nano-liquid chromatography
Z Aturki;S Fanali
2012
Abstract
Three polysaccharide-based chiral stationary phases, Sepapak®1, Sepapak®2 and Sepapak®3 have been evaluated in the present work for the stereoisomer separation of a group of 12 flavonoids including flavanones (flavanone, 4-methoxyflavanone, 6-methoxyflavanone, 7-methoxyflavanone, 2-hydroxyflavanone, 4-hydroxyflavanone, 6-hydroxyflavanone, 7-hydroxyflavanone, hesperetin, narin-genin) and flavanone glycosides (hesperidin, naringin) by nano-liquid chromatography (nano-LC). The behaviour of these chiral stationary phases (CSPs) towards the selected compounds was studied in capil-lary columns (100 m internal diameter (i.d.)) packed with the above mentioned CSPs using polar organic, reversed and normal elution modes. The influence of nature and composition of the mobile phase in terms of concentration and type of organic modifier, buffer type and water content (reversed phase elu-tion mode) on the enantioresolution (Rs), retention factor (k) and enantioselectivity (?) was evaluated. Sepapak®3 showed the best chromatographic results in terms of enantioresolution, enantioselectiv-ity and short analysis time, employing a polar organic phase mode. A mixture of methanol/isopropanol (20/80, v/v) as mobile phase enabled the chiral separation of eight flavanones with enantioresolution factor (Rs) in the range 1.15-4.18. The same analytes were also resolved employing reversed and nor-mal phase modes with mixtures of methanol/water and hexane/ethanol at different ratios as mobile phases, respectively. Loss in resolution for some compounds, broaden peaks and longer analysis times were observed with these last two chromatographic elution modes. Afterwards, a comparison with the other two CSPs was performed. A lower discrimination ability of Sepapak®1 and Sepapak®2 towards all the studied flavanoids was observed. However, Sepapak®1 allowed the separation of naringenin enantiomers and naringin stereoisomers in polar organic phase which were not resolved with the other two CSPs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
