By Anonymous on Monday, January 20, 2003 - 09:20 am:
Hi,
we're doing a determination of vitamins in blood,but the deproteination step is not so efficient (the pressure is increasing ,we use a 3µm C18 column)
can I remove the proteins already adsorbed?
someone already did this?
I thought in use sodium dodecyl sulfate overnight with some organic .
By Gerhard Kratz on Monday, January 20, 2003 - 12:11 pm:
Hi, do you use SPE to clean-up your blood samples? You should do it. For your C18 column try a gradient from 10% -100% Acetonitrile in 0,5% trifluoroacetic acid. Otherwise ask the manufacturer of your column. They should have some guidelines on how to clean the column. We call them OCS sheets. Do you use a guard column? Good luck. Gerhard
By Anonymous on Monday, January 20, 2003 - 12:20 pm:
yes,we use a guard column but no SPE,we use a EtOH deproteination.
I already wash the column with ACN.and the pressure is still high .
Fabiano
By Anonymous on Monday, January 20, 2003 - 03:38 pm:
It is close to impossible to remove the junk that comes from blood samples. You can use a guard column, or you can do more efficient sample clean-up, eg.g. SPE. Also, for protein precipitation, EtOH is not as efficient as MeCN.
By H W Mueller on Monday, January 20, 2003 - 11:22 pm:
We have been through this before. Cleaning out proteins which have been deposited there by MeCN, etc., is difficult. An aqu. solution of Li dodecylsulfate and dithiothreitol has done a good job of rejuvenating columns, but is tedious. I agree with most respondents above: prevention is best. Ultrafiltratin is one of the most efficient ways to get rid of proteins.