Sample Extraction for Tannates

Hi Guys, I am trying to extract tannates in liquid suspension. I tried different solvents like Phosphate buffer/ACN/MeOH , 0.01NHACL/ACN, 0.2%TFA/ACN/MeOH.......but i only extract 90% of phenyl product....other actives come out 100% no matter which solvent i use....any suggestions....i am using HPLC BEH C18 column.Thanks,Sandeep

Answers

  • Greetings Sandeep,

    I don't know if you have gotten tired waiting for an answer or not, but I feel badly that no one has responded to you. I am, basically, out of my league in offering any advice on this question. I was once (a long time ago) educated as a chemist, but I am now much more involved in instrument development and engineering. None the less, just because I don't know what I'm talking about never stops me from having an opinion You seem to be in a scouting mode, anyway. Have you tried any solvents with slightly lower polarity such as 2-propanol, THF or methyl ethyl ketone? Maybe just a touch of one of these would be enough to tip the partition coefficient in your favor. You seem to have tried both sides of the pH spectrum, but did you try NaOH? It might have a specific affinity for the hydroxyl moiaties.

    Regards,

    pcb

  • PCB,

    Thanks for the reply and suggestions. I am actually trying NaOH to see if that works. i will also give a shot with solvents which you have mentioned. Will keep you posted with the results.

    Sandeep

  • This answer has been relayed from one of our chemists in Chemical Analysis Marketing,

    They think the first thing to check is the pKa of tannates and pH of the extraction solvent. The pH of the solution needs to be at least 2 units below the pKa of tannates.

    Good luck.

    Edited by: Elizabeth Hodgdon on Jan 13, 2009

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