protein precipitation: organic ratio vs plasma volume
Posted: Thu Feb 25, 2016 4:12 pm
Hello,
For usual plasma volumes (50-200 ul), the solvent:plasma ratio is often 3:1 (at least with acetonitrile). Now I have read here and there that if one uses lower plasma volumes, for instance 5 or 10 ul, a higher ratio should be used, typically 6:1 or 10:1. Do you know why? I wonder if this is related to differential precipitation efficiency or simply for allowing better recovery of the supernatant after centrifugation.
And I wonder another thing: if I would mix 15ul ACN on 5 ul plasma, then add 50 ul water without prior centrifugation, would proteins redissolve or their denaturation would prevent resolubilisation?
Thanks for your comments
For usual plasma volumes (50-200 ul), the solvent:plasma ratio is often 3:1 (at least with acetonitrile). Now I have read here and there that if one uses lower plasma volumes, for instance 5 or 10 ul, a higher ratio should be used, typically 6:1 or 10:1. Do you know why? I wonder if this is related to differential precipitation efficiency or simply for allowing better recovery of the supernatant after centrifugation.
And I wonder another thing: if I would mix 15ul ACN on 5 ul plasma, then add 50 ul water without prior centrifugation, would proteins redissolve or their denaturation would prevent resolubilisation?
Thanks for your comments