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hello members,
i am working with ellagic acid method development on lc-ms/ms
API-4000. I have developed the mass methodology but facing problem
with the extraction of ellagic acid from blood. ellagic acid is a weak
acid with 4 phenolic OH groups. The method is in -ve mode. Mobile
phase i am using is isochratic with A -2%Acetic acid in Methanol-90parts
B-2% Acetic acid in Water-10 parts.
Kindly provide suggestions, details, literature for the extraction
methodology. I have tried LLE with Diethyl ether,Ethyl acetate, TBME.
regards,
gagan
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The following message was posted to: PharmPK
You can try to add 2% acetic acid into the extraction solvent to
minimize the ionization of ellagic acid in blood. Or try to use 10%
trichloroacetic acid to precipitate the protein.
Chunling
Sloan-Kettering Institute
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Dear Gagan sing
I have work earlier on valproic acid.
You can try 1% NH3 at 30% with ACN in mobile phase also can be work
out if you are using pseudo MRM. You can try Oasis HLB cartridges by
giving wash of 1% or 2%NH3 to cartridge and then elution with
Meoh:water 70:30.
Try this it may work out for acid molecule
Regards
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hello members,
Thanks Mr. Chunling for your suggestion.
i tried with 2% acetic acid in methanol(500ul) and then evaported
it and finally reconstitued in 100ul of methanol. The height i am
getthig for a 100ng/ml spiked conc. was 100. Still recovery is the
issue in my estimation which is coming to 2%. Similarly i tried 200ul
spiked conc. +100ul of 2% acetic acid in water and then tried to
extract with LLE using diethyl ether and reconstituting with 100ul of
methanol and obtained same height.
So the real problem is with the recovery of ellagic acid. If i use a
strong acid then there occurs protonation and subsequent precipitation
of ellagic acid .
Kindly pour in some suggestions regarding the recovery/extraction
technique for ellaagic acid.
thanks and regards,
gagan
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