sometimes i have problem with fat in my extracted alkaloids using ethanol and chloroform for extraction. Also my alkaloids are not well dissolved in acidic water, so acid-base precipitation doesn't help me much with purification. any suggestions?
1- add HCL to alkaloid layer ph 2, then add chloroform 3 time to separate fat (occur in separator funnel )
2- add ammonia to aqueous alkaloid layer to make alkaloid free
3- add chloroform to alkaloids layers
4- the chloroform layer contain alkaloid
best regards
You can try triturating the extract into hexanes, petroleum ether, or cyclohexane. Dissolve the sample in a minimum volume of ethanol or dichloromethane. Add the solution dropwise to to the chosen non-polar solvent with vigorous stirring- use a magnetic stirrer. you want to break up the drops upon addition. The alkaloid should be a solid which can be filtered.
Consider ion exchange for purification of alkaloids (cation exchange):
https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Application%20Notes/Purification%20of%20Alkaloids%20with%20RediSep%20Rf%20SCX%20Columns%20App%20Note.pdf#search=alkaloid
https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Posters/Alkaloid%20Purification%20Strategies%20Using%20Flash%20Chromatography%20Poster.pdf#search=alkaloid
You should be use apolar solvent such as (methanol; hexane; ether....).
1- add HCL to alkaloid layer ph 2, then add chloroform 3 time to separate fat (occur in separator funnel )
2- add ammonia to aqueous alkaloid layer to make alkaloid free
3- add chloroform to alkaloids layers
4- the chloroform layer contain alkaloid
best regards
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