Isomer Separation? Welch columns bring help
It’s usually very difficult to identify the twins, but mothers can easily identify their twins according to habits and characteristics.
Isomer
In Chemical world, there also exist some compounds with similar structure and properties like isomer and enantiomer. It’s very hard to operate chromatography separation on these compounds, for example, Oleanolic acid and Ursolic acid.
To separate these compounds, we need to identity their own characters and choose the right column with unique selectivity. Enantiomer usually can get separation on chiral columns, but today, we will talk about the separation of isomers.
Welch columns with steric hindrance to separate isomers:
Ultisil XS-C18、Ultisil PFP、Ultisil PAH and Ultisil XB-C30
Separation of Oleanolic acid and Ursolic acid on Ultisil XS-C18 and Ultisil XB-C30
Chromatography condition:
Mobile Phase: Acetonitrile: water=93:7
Detector: 210nm
Temperature: 20℃
Flow Rate: 1ml/min
Injection Volume: 10μl
Chromatogram of reference solution on Ultisil XS-C18
Chromatogram of reference solution on Ultisil XB-C30
Conclusion: Ultisil XS-C18 and Ultisil XB-C30 can satisfy the test requirements on separation of Oleanolic acid and Ursolic acid.
Separation of α, β, γ, δ tocopherol on Ultisil PFP
Tocopherol is a hydrolysate of vitamin E. Natural tocopherol is d-tocopherol and it has many isomers like α, β, γ, δ.
Chromatography condition:
Mobile Phase: Methanol/water(Gradient Elution)
Detector: 294nm/325nm
Temperature: 20℃
Flow Rate: 0.8ml/min
Injection Volume: 10μl
Mixed Reference Chromatogram
Conclusion: The fluorine-containing stationary phase of Ultisil PFP has strong geometry and stereo shape selectivity, which can easily help to separate compound with similar structure. It perfectly meets the requirement in this experiment.
Separation of main component and isomer impurities on Ultisil PAH
Chromatography condition:
Mobile Phase: Acetonitrile/water=57/43
Detector: 266nm
Temperature: 35℃
Flow Rate: 1.0ml/min
Injection Volume: 10μl
Mixed Reference Chromatogram
Conclusion: Ultisil PAH(4.6x250mm,5um) can meet the test requirement.