I am isolating compounds from BuOH fraction and initially I did Silica gel column with mobile solvent was (EMW in 100:20:1) now I have plan to proceed with Sephadex LH-20 column. I want to know that can I use the same solve (EMW in 100:20:1) for Sephadex LH-20 column or I can only use MeOH for sephadex. For researcher information my fraction contained highly polar compounds and whenever I checked RP TLC with 10% MeOH the spots move faster and travelled a long distance towards upper end, so I cannot use MeOH as mobile phase if someone know other solvents which can be used with sephadex LH-20 please share with me.
Thanking in advance
Yes, you can use that solvent system for Sephadex LH-20.
The link goes to a PDF file; table 2 lists solvents used with LH-20: https://www.gelifesciences.com/gehcls_images/GELS/Related%20Content/Files/1314716762536/litdoc18110722AB_20110830184615.pdf
Hello,
I have already used the Sephadex LH-20 to isolate saponins (from a VLC fraction MeOH / H2O 40/60) with an elution with MEOH / H2O 0/100; 25/75; 50/50 and 100/0. For me it did not work because I had a lot of tannins.
I have always used only Methanol and water as solvent for LH20 columns and that's what they recommend too. and as you are suggesting your compounds are polar, you should be fine using just these two.
Hope you isolate your compound to the purest form. Good luck
Hello Zaheer,
Yes, you can use the EMW system you have mentioned for your separations. I have used this very effectively for many separations. This is specially useful for polar compounds.
More common solvents that are used with LH 20 are methanol and mixtures of methanol with dichloromethane and CHCl3 etc. With these solvents separations are mainly by size-exclusion (larger molecules eluting faster than smaller ones) However, with the EMW system in addition to the size-exclusion there is also a partitioning effect. Therefore with this system, polar compounds are retained more than the non-polar compounds.
I usually first separate my mixtures on LH 20 with methanol and analyse the fractions by TLC. For fractions that have compounds of different polarities I use the EWM system. Your compounds may take a longer time to elute with this system
Dilip de Silva
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